Axiome 70EP Build Log
 

Hi all! I decided to start a new thread specifically for the build to help organize the information a little better.

Several weeks ago, I was given the opportunity to put together the new Axiome 70EP from Winner’s Model, distributed by F3A Unlimited.

You can find the airplane here: http://bit.ly/1eOZ2iO

Because of the nature of this airplane being one that can both serve as an excellent, cost-effective airplane in which to enter pattern, as well as an incredible smaller airplane for the more experienced pattern guy, I thought it would be a good idea to document the build and setup of this airplane for those who may be looking to get their feet wet in pattern, but don’t quite know how to do it. There are a lot of intangibles that don’t come across in an instruction manual but are paramount to a pattern airplane that’s easy to fly, flies consistently the same, and doesn’t break unless you stick it in the dirt. Optimizing variables (term stolen from a build thread Rusty Dose did several years back) are key to reducing pilot workload, and allowing him to concentrate more on flying, and less on fighting the airplane.

I’ll start off the thread by giving a little background information on the Axiome as well as going over component selection and why I’ve chosen what I’ve chosen. Understand that this isn’t the only way to skin this cat, but these products are those that I buy and use because I truly believe in them, not just because that’s what gets handed to me. I’m a modeler, not a commissioned sales representative. Deduce accordingly.

THE AXIOME

Christophe Paysant-le Roux is a man that needs no introduction. He has matched the great Hanno Prettner with the most number of F3A World Championship wins with seven under his belt as of this writing. After placing second to Giichi Naruke in Poland in 1997, CPLR earned top billing in 1999 in Pensacola, and began his decisive winning streak at a world level, save for a brief dethroning to Quique Somenzini in 2007. In addition to his accomplishments at the world level, Christophe has been European F3A Champion eight times, and according to the best information that I can find, 20+ times as French F3A national champion. Quite the impressive list of achievements, no?

It would stand to reason that a man that can fly at that level could design an airplane that flies pretty well, given that he has designed every airplane with which he has competed. Christophe follows a very logical progression from design to design, and one can easily trace the lineage of his designs. He turned the F3A world on its ear by showing up with a funny-looking appendage on his airplane at the 2005 worlds in France which would later become a trademark design feature of his. That appendage in question, is the canalizer and since then has become one of the most copied parts put on a pattern airplane aside from wings. In 2009, Christophe showed up in Portugal with a new design with a new style. The Oxai Axiome featured a canalizer so large that people began to joke about his airplane being a sesquiplane (one and half wings) instead of a monoplane. After regaining the top spot in Portugal with the Axiome, the airplane has gone one to become one of the most popular F3A airplanes worldwide in the past several years. For an airplane that retails at nearly $5K, that’s no small feat. Its popularity is well-deserved; the airplane flies incredible. Chip Hyde walked away from the competition at the Nats in 2013 flying a pair of Axiomes, and there were quite a few peppering the F3A semi-finals as well.

Luckily for the rest of us mere mortals, there is a slightly more viable option than spending a few mortgage payments for the chance to fly an Axiome. CPLR has shrunk his winning design to an electric-only, 70-sized electric model that has been engineered such that it retains all of the good flight characteristics of the real Axiome albeit in a smaller package. That in itself is no small feat, and to be honest is probably harder to do than to design the original airplane because one has to be mindful not only of the aerodynamics to make a smaller airplane fly like a larger one, but it has to actually look like the airplane as well. The smaller you go, the harder it gets.

EQUIPMENT SELECTION

Asking a pattern flyer what the most important hardware component is in a pattern airplane is much like asking a parent which child is their favorite. Everything in a pattern plane has a function, and in order to have a great flying airplane, all the parts have to work well with one another. A simple break in the system can cause one to chase problems in an airplane for months. I don’t mean to seem dramatic, but the best, most consistent fliers are also the ones that fully understand aircraft setup and use it to their advantage. You can build the most beautiful building in the world, but if you fail to verify the soil condition before construction, you yield a compromised structure that will badly degrade over time.


A. Radio

I have been a loyal JR user from the beginning of my involvement in this hobby. I could extol this companies virtues for hours on end, but I’ll spare everyone the misery and simply state that they are top notch. Their quality is the yardstick by which other companies measure their products and the performance of their radio equipment rivals anything in the marketplace. I won’t go on record as saying “it’s the best” as “best” is very subjective, but I will say that I have preferred JR in every instance over another brand’s equipment. People at the level of flying this type of airplane should have a very clear opinion on where they stand with regard to brand preferences, so I’m not here to try to change anyone’s mind. I’ll provide some comparable equipment at the end of the article for those that prefer different servos.

For the ailerons and elevator, I’m using JR DS3517s. These are mini-sized digital FET servos that have incredible centering and excellent overall performance. There is a higher torque version of this servo called the DS34321, but its torque comes at a speed penalty. I have used both in the same applications before and have been happy with both; I just happened to have a few sitting around and was too cheap to get more. Some fliers more skilled than I can feel a discernable difference in speed, the best I can muster is feeling blowback when the torque of a servo isn’t quite enough to power a control surface.

The rudder is also sized for a mini servo, and I opted for a little more torque and the expense of speed and used a DS3421.

For transmitter, I’ll be using the relatively new JR XG14. This is a really cool little radio and has a lot of great features. One of the first things people notice about the radio are the gimbals; they have been completely redesigned from the other XG-series radios and not only do they feature quad ball bearings, but the entire assembly is supported by a metal strap so that there is no flexibility of the gimbals for a smooth, solid feel normally felt in radios costing over twice as much.
Programming features in this radio are extensive and it can support up to six flight modes for ultimate flexibility for setting up flight conditions for different maneuvers. It also features (6) seven point curve mixes for fine tuning flight performance, a powerful balance function to match servo movement, versatile preformatted wing and tail type programming, dual servo matching, telemetry, and serial bus communication through their proprietary XBus components. With the exception of XBus, all of the aforementioned features are critical to extracting the last shreds of performance out of a pattern airplane. For modelers looking to upgrade from a sport-grade radio, I can’t recommend this one highly enough.

About three years ago, JR released their proprietary RF protocol, DMSS which stands for Dual Modulation Spread Spectrum. This is a hybrid frequency hopping protocol which combines the attributes of a direct sequence modulation system which transmits wide band signal packets across the entire band of 80 channels to give the ultimate in signal diversity. Being a wide-band signal, DMSS is much more impervious to signal blanking than other narrow-band FHSS systems on the market. That means more complete signal packets get transmitted to your model.

Neglecting the irrelevant tech talk, the cool thing that makes DMSS so unique is that it supports telemetry automatically. There are no additional modules to purchase to access the telemetry; every transmitter and every receiver supports it by design. Receiver voltage is standard for all DMSS systems, and additional modules can be purchased to give one insight on virtually every metric related to a model’s operation. The voltage is excellent peace of mind for ANY model. It’s never fun to be a spectator because your receiver battery died.

Receiver selection is the RG631B, which is a full-range receiver. There’s nothing too special about the receiver selection, pick one that’s full range and the highest speed you can. The size, weight, price, and performance were spot on with this receiver relative to the requirements I had.

Radio equipment is the most tangible link to your model, so be sure not to skimp here.


B. Powerplant

For the business end of this airplane, I have chosen a Hacker A50-14XS motor, Castle Creations Phoenix EDGE 100 Lite, and a mixture of Thunder Power 5S 4400 45C and Power Unlimited 5S 4500 35C batteries. I chose these accessories because I have used the brands for a very long time and have been a satisfied customer for years. These companies have been pioneers of their respective categories and are leaders in innovation and give more back to the hobby in terms of donations, support, and technological advances than any other companies that I’ve seen. The levels of quality of these products is unparalleled by their competitors and any of the budget-branded items in the market today. What’s more, if you have a problem with your product, their service is quite literally next to none, and I’ve never felt dissatisfied with any of my dealings with these companies. They are not always the least expensive options, however I’ve been a firm believer of buying once and that you get what you pay for.

The motor choice dictated the specific requirements for the rest of the components for the airplane. With an advertised empty weight of 2100-2200 grams, the heavy range for 5S 4400 batteries being 600 grams, the most this airplane should weigh is 2800 grams or 6 pounds, 3 ounces. In order to have truly unlimited performance, one needs to have over 150 watts of power per pound. Delivering 1250 watts on 5S, the A50-14XS gives us 202 watts per pound…more than enough. This is a little hotter wind motor, but it is still recommended to turn a 15x8 propeller on 5S. I will do more experimenting when I fly the airplane more, but 15x8 should be in the ballpark.

Quality and design are the two main things that set this motor apart from the more prevalent, cheaper motors in the marketplace. The basic specs of the motor (14 pole, 520Kv) are pretty easily attainable at a lower cost than the Hacker. Some of the advantages the Hacker has over cheaper motors are:

1. Much higher quality machining. The German standard for machine work has always been exceptionally high. The door hinges on my Volkswagen Passat are a thing of beauty compared to the hinges in my last car, which was a Ford Explorer. The machining tolerances are much closer, there is a much better finish to the parts with no apparent tool marks, no burrs or other defects, and a much higher quality raw bar stock. This translates into a much truer running outrunner motor that stays balanced and whose performance will not change as the motor heats and cools during the flight.

2. Curved magnets. A curved magnet allows closer placement to the stator, increasing the magnetic flux because of more complete surface “contact”, thus creating more torque. This, combined with an optimum stator design, means more power for a given size motor than one with flat magnets.

3. Oversized bearings. This design drastically reduces the amount of vibration in the motor (which is close to nil anyway since these are electric motors and are dynamically balanced), gives much better support to the main shaft, and dissipates heat better.

4. Integrated fan. Not many other motors in the market that are this size feature an integrated fan. The benefits of this one are obvious; it moves much more cooling air through the motor. The less drastic a temperature change a motor undergoes, the better it will run.

With motor selection sorted, the next order of business was to get the ESC. I have been a Castle Creations customer for many years now, so there was never a question of NOT putting a Castle ESC in my airplane, the question was simply, “which one?” Castle recently announced their new Phoenix EDGE series of controllers that are a replacement to their ICE controllers. The EDGE series controllers have some pretty cool features like integrated data logging, powerful programming interface (completely free; the download is free and there is a coupon included in the box for a free Castle Link), and my favorite, adjustable BEC voltage that’s programmable from 4.8-8.4v. I think that’s really cool, most other controllers that I’ve seen/used only have non-selectable 5.5v BEC output. I always like running my servos at 6v for better performance. I’ve never found myself wanting less torque or slower transit times. I went a little overkill on the amp rating of the controller for a few reasons.

1. The max burst current for the Hacker is 70A, which is less than the 75A continuous rating of the EDGE 75 controller. Unloaded in the air, the value will likely be substantially lower, but to offset the fact that this controller doesn’t have the second, larger heat sink, I wanted to ensure that heat dissipation would be a non-issue.

2. With this controller featuring a switch mode BEC, I didn’t want to skirt too close to the total power demands that the entire system (motor and servos) would put on it. I shouldn’t even come close to half of the 5A peak output of the BEC in a power hungry maneuver such as a snap roll, so the controller will not be overworked. That said, the instant digital servos move from center, they can peak at 2-3A each, but soon settle down to their normal 200-250mAh levels. Normal inline current meters cannot measure this; it must be viewed on an oscilloscope. A good test to determine whether or not you will have any issues with your setup is to “stir” the sticks, meaning move all of the control surfaces at the same time. I did this with the engine off and at full throttle (with someone holding the airplane, of course) and noted no issues.

Looking at the construction of the Castle controllers is quite reassuring that you’re getting a quality product. The boards have a very nice appearance and are very well laid out. All of the solder connections are beautiful and nothing looks like it was ever too hot, nor are there any traces of a cold solder joint. I am overly critical of the performance of ESCs when I’m not using external power as it truly is the heartbeat of the model. If it fails, it doesn’t matter how good your radio system is, there is nothing to power it. As stated before, I don’t like to be a spectator.

The last piece of the power puzzle are the batteries. Again, I’ve been a Thunder Power customer from my first LiPo battery, and have enjoyed a wonderful relationship with them over the years. Thunder Power was formed back in 2003 and was one of (if not) the first manufacturers to bring LiPo batteries to market in the hobby industry. They continue to be pioneers in the industry aggressively developing newer chemistries that provide for even higher discharge capacity, lower weight, and better stability than ever before. Furthermore, the new G8 packs can be charged at a higher rate, have matched IR during assembly, and have a very long lifespan. Not many other battery manufacturers work so hard to develop and improve their product. Thunder Power don’t simply sit idly by, they truly push the bounds of quality and performance and have long been the yardstick by which other batteries compare. In addition to all of this, they feature a 50% off crash warranty, so it reduces your burden substantially if you lose a pack to crash damage. I chose their 4400mAh pack for a good balance between weight and flight time, and obviously chose 5S for the voltage.

When I picked the airplane up from Mike a few weeks ago, he slipped an extra surprise in with my stuff- one of his Power Unlimited 4500mAh 35C 5S packs. Mike and I have grown to be great friends and flew together quite a bit last year. Mike has been very proud of his Power Unlimited packs, and rightly so. He loves to pull them out of an airplane and hand them to an unsuspecting bystander. In the middle of the summer after a Master’s flight, they were downright cool. I’ve even handled some of Brandon Sobolewski’s packs after a flight and they were equally cool, equally firm and didn’t appear to be lacking in power at all…and Brandon flies a lot. One thing about Mike, is that he’s an honest guy. I measured the weight of my battery pack and checked it against his published spec on the website and there was a discrepancy of 8g…the difference between the battery with no connector, and the weight of my Dean’s Ultra with extra heat shrink. Pretty cool. His batteries are really on the lightweight end of the spectrum and I’m looking forward to flying it more. They no doubt have performance to back up their claims. I like also that the batteries feature the Thunder Power balance connectors. They are much smaller, streamlined, and a lot better design than the normal JST-XH connectors you find on other batteries. Plus, I don’t need any special balance board adapter since I’m totally invested in Thunder Power packs.

At the end of the day, caveat emptor. I don’t mean to come across as being overly dramatic, but there is a big difference in performance when you use quality products over the cheapest things you can find. Contrary to popular belief, I’m cheap. I have enough things in my life that don’t go according to any plan I may have had, so when I unwind and enjoy my hobby, I like the peace of mind knowing that my equipment choices won’t prevent me from enjoying my time at the field. I also like knowing I didn’t throw money away with any of these companies as their support and warranties are second to none. In fact, you’re lucky to get a 30-day limited warranty with many companies. JR features a three year warranty, Thunder Power and Hacker a two-year warranty, and Castle a one-year warranty. I can happily say that I’ve never had to use any of them, but I like knowing that they are available to me should the need arise. I like to support companies that will support me in return.


C. Miscellaneous Accessories

I hate Phillips head screws. Despise them. I can’t stand them. I’m repulsed by them. Any opportunity that arises where I can substitute a Philips head screw for a socket head, I jump all over it. You may notice in the pictures that I have some purple screws for my servo mounting and output shaft screws. These are some really nice anodized aluminum screws from a company called Fastener Express (www.fastener-express.com) out in California. I think I first started ordering from them in 2008 when I started looking for a replacement servo mounting screw. I didn’t really care for the DuBro steel hex head screws as they were too small. JR servo grommets can support up to a #4 screw versus the smaller grommets for Futaba servos, so a quick Google search yielded this place, and I’ve been doing my part to keep them in business ever since. The standard offering for an aluminum servo mounting screw from them is #4x5/8” and can either be plain aluminum, or a variety of other colors. I always go for purple; it’s just become my “standard” color. All of my pattern airplanes have featured red/yellow/purple/silver trim, and I’ve always just been drawn to the color. The M3x6 aluminum button socket head screws work beautifully in the servo output shafts for JR metal gear servos. Finally, I had been looking for a smaller anodized aluminum solution for mid-sized and micro servos as they do not support a #4 screw. Some thought and experimentation has yielded using their #2 anodized aluminum machine screws for this purpose. I use a 3/8” length screw and have been very happy with the results so far. Because the socket is so small and the aluminum is so soft, it’s imperative to use a hardened steel hex driver and solid pressure on the screw when you are installing. In fact, I actually use a 2-56 tap to tap the mounting holes, harden with thin CA, and then run the tap through again. This setup is every bit as solid as using the standard steel screws from my experience. There is the “cool” factor of the anodized screws, but there is also some weight savings going from steel to aluminum. Every little bit counts!

For servo arms, I’m using Hangar 9 offerings with the aileron and elevator horns being their standard half arms, and the rudder utilizing their 35mm pull-pull wheel. The standard half arms feature 2mm threads which are standard for ball links in ARFs, MK hardware, etc. and are of very nice construction. I’ve always used pull-pull wheels in my pattern airplanes because I love the performance. The opposite cable never goes slack because of the geometry of the wheel, and there isn’t any sort of compound pressure during the travel of the wheel because there is always perfect geometry. I haven’t found the distance from the hinge line to the linkage attachment point on the rudder to be hugely critical for the wheel. Certainly, they need to be relatively closely matched, but if the total width in the rear is greater than the width of the wheel, then you can simply cross the cables to compensate. All this was figured out by flyers much smarter than I; I’m simply dumb enough to not mess with a proven system.

BEFORE ASSEMBLY

Because of my prior employment as a product developer at Horizon Hobby, I have gotten in the habit of weighing everything with ARFs. As the person simply assembling the parts, there is little in your power to control the weight of the individual components, but it helps arm yourself with knowledge so that you can make appropriate equipment choices, and have a much better idea of what to expect out of the finished model. Normally, I’ll do a weight buildup to include the weights of all hardware items, but for this airplane, it’s not as critical, and I doubt many of you here would care to hear the weights of screws and washers. I tend to weigh and measure model airplane construction in the metric system as a ten base is much easier for me to calculate and decipher. That said; the individual component weights are as follows.

Fuselage: 614g
Canalizer: 32g
Canopy: 80g
Cowling: 66g
Left wing panel: 172g
Left aileron: 30g
Right wing panel: 166g
Right aileron: 32g
Horizontal stabilizer: 78g
Elevators with joiner: 26g
Rudder: 32g
Wing tube: 46g
Landing gear legs (both): 60g
Wheelpants (both): 32g

Not too shabby. The engineering of this airplane is among some of the best I’ve seen among the different manufacturers over in Asia. I didn’t bother to get hardware weights as they aren’t something that can really be controlled. If you prefer, substitute lighter weight aluminum hardware or do like I do, trim any excess bolt length, if applicable.

If you wish, take this time to go over your airplane with a heat gun and/or covering iron. I’ll warn you, your airplane will probably wrinkle again, so I don’t spend too much time on shrinking covering at this stage in the game. Rather, I keep my covering iron handy to iron down covering on a specific part that I’m working on, such as the horizontal stabilizer after I trim the covering for installation, and the fuselage around the stab saddle before I glue the stab in. Also, a covering iron is just as important to my hinging technique as glue is.

I do, however, take the time to neatly open any and all holes in the covering for wing tubes, servo leads, pull-pull cables, cooling exits, etc. That said, I don’t simply cut the covering flush with the edge, or use a soldering iron to melt the covering (yuck!). I will fold the covering into the holes, unless it’s something like a tube socket, in which case I will cut flush with the edge. Folding the covering in yields a much nicer finished appearance, and will not lift during normal use. Furthermore, it will not pull away when you try to shrink covering adjacent to it. It takes very little extra time to fold the covering into an opening, but the professional appearance and better performance gained is well worth the extra effort.

As stated, I do not like to melt covering with a soldering iron. First of all, it will trash tips in a heartbeat and leave pigment and residue that can bleed to other colors. Temperature control is critical with this method; most covering begins to shrink at 300 degrees, so unless you have a higher end soldering station, chances are you are going to burn the covering and make a big mess. Extra finish work is required with this method as it leaves a ridge of burned, discolored plastic around the edge of the hole you were trying to open, so you still have to try to trim that away with a #11 blade. Because this lump of melted plastic is so much harder than the surrounding balsa wood, it’s easy to nick the edges of the part. I will say, it’s a much quicker method to open holes, but the final appearance makes it look like you spend even less time than you did to open the holes. Remember this; there are no points for building your airplane the quickest.

LANDING GEAR INSTALLATION

The first thing I like to do when assembling a model is to install the landing gear. I don’t really like to work with the airplane on stands just as a personal preference. Also, it’s nice to be able to set the model aside without damaging the finish. For these reasons, all of my ARF assemblies begin with landing gear installation. I will start by installing the axles and tires onto the landing gear legs and then install the finished assemblies onto the model. To install the wheels and tires, you’ll need:

(1) left and right landing gear leg
(2) tires; the tires were missing from the hardware pack in my model, I simply substituted with 2-inch lightweight Du-Bro
(2) M4x30 socket head cap screws
(4) M4 flat washers
(4) M4 lock nuts

For tools and materials, you’ll require:
Light oil
3mm hex head driver
7mm wrench
Needle nose pliers

Begin by generously oiling the M4 bolts near the head. I’m a stickler for wheels that rotate freely and don’t squeak, so this is something that I do on every airplane, regardless of type. Because this airplane isn’t a glow model, there is no concern of the model taxiing away from you on a hard surface at idle. I’ve found that wheels that spin freely will make ground control, particularly at the beginning of the takeoff roll and the end of the landing roll, much easier as you don’t have one wheel grabbing. I find that the model doesn’t roll any appreciably longer on rollout having lubricated axles, and it most certainly doesn’t squeak. If you fly off of grass, this is a little bit less of a concern, but unfortunately 90% of my flying is done off of a hard surface, therefore this has become more or less a necessity.

Slide the wheel onto the bolt, and thread one of the M4 locknuts onto the bolt. Using your 7mm wrench and 3mm hex driver, tighten the nut down until it is tight against the tire. Not so tight that it compresses the wheel, but tight enough that it doesn’t rotate. Now, back the locknut off of the wheel ¼ of a turn or until the tire moves freely, and repeat this process with the other wheel and axle.
Once this is complete, slide an M4 flat washer onto the axle, push the axle through the hole in the landing gear strut, slide another M4 washer on the axle on the back side of the landing gear strut, and then begin to thread the other M4 locknut onto the bolt, threading as far as you can with your fingers. Repeat this process for the other landing gear leg.

Take your 7mm wrench and 3mm hex driver and again tighten the locknut. This operation takes a little finesse so that you don’t start to tighten the first bolt back down, so I find it easy to take a pair of needle nose pliers (as I don’t have a second 7mm wrench) and hold the nut nearest the tire with the same hand that is holding the 3mm wrench to prevent that nut from moving while I snug the retaining M4 nut down. Ensure that the axle is tight against the gear leg and that your wheel still spins freely without having any lateral play. Repeat for the other gear leg.

To install the complete gear leg assemblies, you’ll need:
(1) left and right landing gear assembly
(6) M3x15 socket head cap screws
(6) M3 flat washers

Slide one of the gear legs into the fuselage and verify alignment with the preinstalled blind nuts. I noticed that my outer two holes would not align perfectly, so I had to slot them slightly. The innermost hole (single hole) aligned well, so it did not need to be modified. Carefully slot the holes as necessary, ensuring not to elongate them laterally, only longitudinally. You do not want to introduce any play into the system. Ordinarily this adjustment would be the other way around…on the fuselage and not on the gear leg. Functionally they are the same, but there is a little more room for error on the gear leg. Once satisfied with the alignment, slide the gear leg into place (with the sweep aft!) and put your first bolt in.

Because the gear plate is underneath the battery tray, save yourself some curse words and frustration and install the bolts with a telescoping magnet. The magnet I have has a head that is about 3/16” diameter, so it fit through the slots for the battery straps easily. Also, it’s strong enough that the M3 washer will not fall off, but not so strong that you can’t break the attraction after you have the bolt seated in the hole. Alternatively, you can magnetize a 2.5mm hex driver. Put a generous few drops of blue threadlock on the bolts and tighten them down.

Now that the airplane is sitting on its own two feet, you can go ahead and install the wheelpants. There are many different ways to skin this cat, however I’ll detail the method I used on this build. The process is pretty straightforward as the pants are pre-slotted for the axles. If you care to, ensure that the slots are the same elevation into the pant; on my airplane I found that they were even with one another, so no adjustment was necessary for them to fit properly.

First, put a piece of tape lengthwise down the outside edge of each pant and sit it down on a flat surface. Because these wheelpants have a flat bottom, you can simply measure up some arbitrary amount on the front and rear of the pant and make a dot, then draw a line connecting the two. This will be your level line. Next, block the fuselage up to the angle at which it will fly (I simply used the canopy frame as a zero line, it was close enough) and set one of the wheelpants on the axle. Level the line with your table and mark the screw holes. Take a 1/16” drill bit in a pin vise and drill the screw holes. Thread the included self-tapping screws into the holes, saturate with thin CA and you’re done. I generally leave the wheelpants off until I’m completely finished with the airplane so that they don’t get dinged or damaged during the rest of the building process. Main gear installation is now complete, and you can move on to the tailwheel.

The included tailwheel is a pretty nice unit; identical in design to Oxai airplanes, it uses a machined aluminum main threaded assembly instead of a repurposed nylon bolt. The hole for the tailwheel is already laser cut into the bottom of the fuselage, so two quick slices of the covering 90 degrees to one another to gain access to the hole and the assembly is ready for threading. Thread as far as you can by hand and finish with a 7mm wrench. Back the assembly back out after you have cut the threads, and wick thin CA into the threads to harden them. The CA will wick into the wood quite nicely, so ensure that you are properly saturating the wood, but not so much that you seal off the wood and cause the CA to drip everywhere.

Put a few drops of oil on the top and bottom of the wire as it enters into the threaded housing and rotate around to allow it to wick in. Reinstall the assembly after giving the CA a minute or two to fully cure, and if you’re picky, align the unit with the centerline of the fuselage. The tailwheel and collar can be installed now; lubricate the wire with more oil, put some threadlocker on the setscrew of the wheel collar, and tighten down snug with a 1.5mm hex driver. I always align the setscrew aft because I’ve theorized at some point that it has a lesser chance of being disrupted in that orientation. Realistically, if you are generous with the Loctite and with the torque, you won’t have any problems. Be sure to hang onto the rest of the tailwheel parts, the steering arm, the spring, and the attach screw as you’ll need these after the rudder is installed.

ELEVATOR SERVO INSTALLATION

My servo selection for this airplane was based on prior experience with airplanes of this size and also because of the servo selection published by CPLR. When I was opening up the covering for various holes in the fuselage, I saw immediately that the provided hole for the elevator servo was too small. Opening this up is much easier accomplished before stab installation than it is after, so I made a command decision to break the normal order of operations and resize the hole to accommodate the servo as the first thing in this build. A discussion with the factory confirmed that they are aware that the class servo I chose is more important for setting the airplane up as a precision airplane, and are looking to integrate this into future production runs of the airplane. For guys in the first production run, you’ll need to do this. It takes about ten minutes to do and is not difficult at all to perform. You’ll need the following:

Calipers
Ruler
Low tack masking tape
Fine point pen, mechanical pencil
Knife handle with #11 and #18 heavyweight chisel tip
Various sanding blocks
Pin vise with 1/16-inch drill bit
Plywood servo shims
Servo
Covering iron
Thin CA

First, remove the covering from the hole. You can simply trim the covering flush with the opening as there is no point folding it in and then outline the hole with ¾” low tack masking tape. Take your calipers and measure the overall length and width of the body of the servo. Add 2mm to the length measurement and a millimeter or so to the width to ensure that the only portion of the servo that makes contact with the airframe when installed are the mounts themselves. I am not a fan of mounting a servo directly onto soft wood, therefore, I measured the overall length of the servo with the grommets installed and added about 2mm to this measurement and removed the balsa underneath that the servo insets into the skin of the fuselage slightly. This gives a much nicer aesthetic, as well as prevents the balsa from crushing underneath the servo when you tighten it down. Once you remove the top balsa sheeting, you can begin to resize the plywood mount to accept the servo.

Carefully cut through the sheeting of the fuselage to reveal the plywood mount. Use a ruler to keep the side cuts straight, but don’t go all the way to the corners. Use the #18 chisel blade to accomplish this. Once satisfied that you have cut the perimeter of the opening down to the plywood mount, take the chisel blade and remove the sheeting to reveal the inner plywood mount. Take your calipers and measure the overall length of the servo case and add two millimeters to this overall dimension. Measure the difference in the pocket you created and the new dimension, and make marks from each end to denote your actual servo mount opening. Again, carefully and with a very sharp blade, cut along your marks through the plywood to enlarge the mount to accept your servo. Don’t try to cut all the way through at once; in fact try to only make very shallow cuts and always cut away from the corners so that you don’t create stress risers or risk slipping and cutting covering. Patience and a steady hand will soon reveal a properly sized servo opening for your servo. Clean up the sides with some sanding blocks. I will glue sandpaper to pretty much anything to the shape I need. I’ve got some scrap pieces of thick brass sheet in various widths that I glue sandpaper to for the purpose of shoring up small openings. Permagrit tools are very nice, but I don’t have anything of theirs small enough to work in an opening this size. Now is also a good time to take your covering iron and give the area a good once over one more time to ensure that the covering is well-adhered since tape was lifted from the area.

Using double-sided tape, tape some thin plywood shims (I believe mine were 1/32” for the elevator servo) to each side of the servo so that it is perfectly centered in your opening. Center the servo longitudinally in the opening, and mark the mounting holes with a mechanical pencil or pen. Remove the servo and use your pin vise to drill the mounting holes. Thread the servo mounting screws through the holes, and saturate the holes with thin CA. I got a little zealous with the CA and actually saturated the entire area of exposed plywood to give a little extra strength to the corners and the remaining sheeting. Remove the shims from the servo and put it to the side for now.

HORIZONTAL STABILIZER INSTALLATION

Stab installation is by far the most critical part of assembling an ARF airplane. Fortunately, it’s a relatively simple procedure compared to building a kit, but errors in trammeling can cause a good design to fly very poorly. I normally do this next so that I can go ahead and get it out of the way before I get too worked up in other details of the project that may have gotten me frustrated and make me want to rush. This is something that you want to take your time with. If you’ve had a bad day at the office, crack open a cold one and watch some TV instead. If you’ve partaken in one too many cold ones in your cool down process, perhaps you’d still better wait until you’ve got a clear head and calm nerves. It never hurts to have a modeling buddy over to put a second set of eyes on this as well.

One thing is for certain, there is no race to get an airplane in the air the quickest. You can become fast through experience, but the only reward you get is with a good flying airplane.

The Axiome 70 stab is one-piece, airfoiled construction. It is remarkably well built and straight, so the installation process is very easy. Start by sliding the wings onto the wingtube and bolting them into place. Even though you’re not setting any incidence angles, I find it easier to block the airplane up as though you were. Like mounting the wheelpants, use the canopy frame as your zero line reference. Block the tail up and chock the tires so that the airplane can’t roll.

Slide the horizontal stabilizer in place, firmly ensure that it’s seated as far forward as it can go and center up the best you can. Do not rely on the covering layout to center the stab as it will be wrong. Measure the span of the stab outside of the fuselage using the same reference points on the left and right sides. This will ensure that the stab is centered in the fuselage perfectly.
Now, triangulate the stab to the wings. One note of caution here…ensure that you are using reference points that are made by laser interlocking of parts and not places that are sanded to size. Wingtip outer corners are horrible places from which to measure because they can be off a few millimeters and while the rest of the wing will be square, your stab will be misaligned; measure from the outside corner of the aileron cutout in the wing to the outside corner of the elevator cutout in the stab. These are your most accurate reference points on this type of model.

Once the stab has been triangulated to the wing, mark the outline of the fuselage on the stab, left and right, top and bottom, with a fine point marker and pull the stab out. Using a very sharp blade, cut 1/16-1/8” inside this line, leaving about ¼” covering intact along the trailing edge as this will be visible once the stab is installed since there is an elevator joiner that passes through the fuselage. Use light pressure, just enough to cut the covering. Many people recommend using a soldering iron; your mileage may vary, but again, I do not like using a soldering iron to remove covering like this. I find it messier and no easier to do than with a sharp blade. Once the covering is removed, Take your covering iron and give the seams a good once over to ensure that the covering is well adhered. It’s a good idea to touch up the areas around the saddle once more since it will be much more difficult to do so once the stabilizer is in place.

Reinstall the stab, triangulating it again and stand back from the model about ten feet and check to see how level it is with the wing. There may be a small difference that needs to be adjusted out with a shim before you glue it into place. Take note of this at this time and prepare a shim if necessary. A lot of guys use lasers and other sorts of high-tech equipment to level stabilizers to wings, and that may have a place in a two-meter model, but I don’t see a need here. My “workshop” is my dining room table, so I don’t want to drag out a bunch of equipment that my eyeballs can sight just as easily. The Mk 1 eyeball is a very powerful tool…

In my case, the right side of the stab was sitting a little low, so I sanded down a piece of 1/16” balsa sheet into a wedge as best I could and saturated it with thin CA so that it would insert easier in between the saddle and the stabilizer without cracking, bending, or breaking. I anticipate that it was probably 1/64” on one end and 1/32” on the other, so it was pretty thin and quite flexible, particularly cross grain. Insert the shim and adjust until the stab is level with the wing. Verify the trammeling one last time and once completely satisfied that the stab is square, level, and positioned properly, carefully wick thin CA into the joint on the top side only. Wait about a minute and flip the airplane over in a stand. Carefully tack the shim (if applicable) in place with a drop of thin CA on the saddle side, and then take a sharp blade to trim the excess wood protruding outside the fuselage side. Wick thin CA along the seam on the bottom side and let the airplane sit for a few minutes. When wicking CA into the join, ensure full saturation, but don’t wick so much in that it seals the wood and begins to run off as it will make a big mess. If the relative humidity of your building room is high, the CA will more than likely “fog” when it cures, leaving a chalky haze on the covering. This is not a big deal and can be cleaned up very easily with some CA debonder (or simply acetone, though it is less effective) on a Q-tip. Go back and clean the area with some glass cleaner and a clean paper towel to remove any sticky residue that it will leave behind.

Congratulations! You have just done the most difficult task building this airplane. It’s all downhill from here.

MOTOR INSTALLATION

I generally tackle the motor installation next. Flip the airplane back upright and study the firewall. There are 45 degree lines on the face of the firewall that will help you to align the motor, as well as some circles to mark where to drill…if your motor’s mount has those dimensions. I highlighted these lines for clarity for the purposes of demonstration, but you may find it easier to see when you are marking the firewall for drilling.

Place your motor’s X mount on the firewall and align so each line bisects the center of the mounting holes, and mark them. You’ll see that the mounting dimensions for the Hacker are slightly further apart than those marked. Mark the center of these holes (I find a spring-loaded center punch very handy for the task, although an awl works quite well also) and drill a pilot hole with a 1/8” drill bit. Enlarge these holes with a 5/32” drill bit (or 4.3mm if you have metric bits) so that you create a tight fit for the M4 motor mounting bolts. DO NOT DRILL A CLEARANCE! Locate the following hardware items:

(4) M4x20 socket head cap screws
(8) M4 flat washers
(4) M4 lock nuts

Slide one M4 flat washer onto each M4 bolt and thread the bolts through the rear of the firewall so that you create studs on the front side of the firewall with the threaded end of the bolt. You may find it easier to run one of the bolts through the face of the firewall to cut threads first. There should be enough tension on the threads that the bolts stay in place through the firewall.

Attach the X mount adapter to the back of your motor, and the prop adapter to the front. Be generous with the threadlocker on these parts and torque them down adequately. Slide the motor on the four motor mounting bolts and slide the remaining four flat washers on the bolts. Thread the M4 locknuts on the bolts until you can no longer turn them with your fingers and using a 7mm wrench and a 3mm hex driver, tighten the nuts to the face of the motor mount. I much prefer this arrangement as it doesn’t necessitate a third hand to try to get bolt started to get the motor mounted on the firewall while you are trying to hold the motor in position to get a bolt started. Furthermore, it prevents a long bolt from sticking out inside the fuselage to impale your battery should it come loose.

Take this time to locate the cowling and verify that your motor does not need to be shimmed out any to clear the nose ring of the cowling. I found that I wanted a little extra spacing, so I used a spare X mount I had (from ordering one when I was too stupid to read that one was included with the motor) as a pattern to make a couple of shims from 1/32” aircraft plywood. I ended up only using one shim, but cut two because I wasn’t sure how well it would fit until after I mounted the cowling permanently.

Just a quick question, sorry to interrupt this excellent build thread
is there a reason for using red vs. blue thread locker?

Thanks for the great report Ryan. We will have the planes in 2 weeks.
Mike Mueller

If you look on the bottle, or at the nozzle, it is actually Blue. For some reason, many of the manufacturers sell the blue thread lock in red bottles, and red stuff in blue bottles. Makes NO sense and has caused headaches, but it still happens,

Arch

Sorry for the delay, guys. I had a few things come up, but we're back on track!

To answer the question about Loctite, there are many formulations of threadlocker. See below for more than you probably ever wanted to know on the subject. These number correspond to the Loctite brand, however most threadlockers that I've seen follow the same general color coding guidelines.

271, Red: High strength threadlocker for larger diameter hardware.
262, Red: High strength threadlocker for hardware smaller than that which uses 271.
609, Green: Retaining compound, high strength, for mounting slip fit bearings to shafts. An appropriate product for tail boxes.
603, Green: Retaining compound, high strength, similar to 609 but good where the parts may be a little oily.
640: Green: Retaining compound, high strength. Similar to 609 and 603. Lacks the oil tolerance of 603. Use use it where there might be trouble with adjacent bearing contamination with the product.
638, Green, rather thick: Ultra strong retaining compound for assemblies with a marked amount of slop in the fit, min 0.004".
290, Green: Wicking product for thread locking AFTER assembly. Medium strength, much stronger than 242 blue in my experience.
242, 243 Blue: Classic medium strength threadlocker for most of our threadlocking applications. 243 is the oil tolerant version.
222MS, Purple: Low strength threadlocker for small diameter or otherwise delicate fasteners.

Bottom line, I use 242 for pretty much everything with pattern planes. Sometimes 290 can be helpful when assembling linkages and such, but I'm really not that diverse in my use of threadlocker.

ESC INSTALLATION

I like to take this time to install the ESC while everything is still accessible and before the motor has been permanently installed. I learned through Dave Lockhart, who I believe was told this by Steve Rogers at Castle Creations, that bullet connectors do not perform well in permanent/semi-permanent installations. They are designed to be used, not connected once and left dormant. Because of this, I hardwired the wires together on the ESC and motor. It’s a little more work to do, but yields a very nice installation with ancillary bonus of saving considerable weight.

Since the soldering iron is already out, I decided to go ahead and solder the battery connector to the ESC to mount the ESC permanently. I am a recovering EC3 user having recently converted back to Dean’s Ultra connectors so I was primed for this to be an exercise in futility. My soldering skills have improved greatly since the last time I soldered a Dean’s Ultra plug, as has my patience level. I approached the process with a little better order of operations thinking of how I could use fixtures to make my life easier. I used a few scraps of wood, some wooden clothespins and other forms of questionable engineering to stabilize the connecter itself, as well as the wires while I soldered them. I found the process to be easier than soldering my beloved bullets for EC3s and am a bit puzzled as to why I didn’t figure this out a long time ago. I felt that the actual solder joint was a lot better than some of the solder joints I’ve done on bullet connectors, and I had the added benefit of being able to visually inspect the solder joint afterwards. I’m happy with my decision to revert back to Dean’s Ultra connectors.

I found that there were no provisions to pass an assembled battery connector through the main forward bulkhead, so I merged two of the lightening holes in that former. I’ve found that many countries prefer to use bullet connectors for their battery/ESC connection, and bullets are featured in the instruction manual. No big deal, and it takes all of one minute to do a nice job on.

Because the Edge 100 Lite does not have any mounting tabs, I simply doubled some double-sided foam tape on the backside of the controller, and secured it with a piece of Velcro. Quick, painless, lightweight, and secure; time now to permanently mount the motor and move on to grander things.

COWLING INSTALLATION

Cowling installation is pretty straightforward and takes just a few minutes to do a quality job. I tend to mount removable cowlings in a similar manner to mounting a motor in a pattern airplane with a fixed cowling. The tools and materials I used for this are:

Double-sided tape
1/16-inch plywood shims
Low-tack masking tape
Ruler
Fine point pen
Pin vice with 1/16-inch drill bit
Thin CA
Sanding block

Begin by verifying that your spinner backplate will fit on the propeller shaft of the motor and drill out if necessary. I found that I needed to open up the hole for the prop shaft considerably. Take your time, use a drill press, and use incremental bits to work your way up to the final hole size, don’t simply bore through with the final bit size as you’ll end up damaging your backplate.

Tape four small squares of double-sided tape to the spinner backplate and to the nose ring of the cowling. Place the four 1/16-inch shims on one of the surfaces and then align the spinner to the cowling and press to the cowling. Begin the trial fitting process of the cowling and carefully trim the rear of the cowling, if required to ensure an even seat along the back. Once you’ve achieve a nice final fit of the cowling with the spinner butting up firmly to the face of the prop adapter on the motor (bolting the propeller in place helps greatly for this step), align the rear of the rear of the cowling and tape the rear joint along its entire length on the left and right sides. Measure forward 7mm from the joint and make a full-length vertical line. Measure 20mm down from the top of the canopy frame, and up 20mm from the bottom of the fuselage and make cross hatches on the vertical line you just drew. Using your pin vise, drill a hole at one of the marks on the top side and thread one of the mounting screws in place to hold the cowling. Work your way around to the other side, and do the same, then finish with the bottom holes.

Unscrew the screws, and carefully peel the tape back over itself to prevent from chipping the cowling. The paint on the cowling is really nicely finished and holds up well, so the chance of cracking is very slim, however it’s still good practice to peel tape from any finished surface this way, particularly since it is surrounding a hole you’ve drilled. Separate the spinner and cowling, remove tape residue and you’ll see that you are left with four perfectly centered holes along the cowl mounting doubler. Wick some thin CA into these holes and call it a day. You can choose to permanently install the cowling at this point, or you can leave it off until you’re done with the build to reduce chance for damage. I chose the latter; but ensure that you don’t lose the cowl mounting screws. I simply threaded them back into the holes in the fuselage.

RADIO INSTALLATION

I’ve already touched on the skills and techniques used to install the servos with the previous section detailing elevator servo installation. Unfortunately, since the aileron servos are also undersized, resizing the pockets is necessary to fit the required servos. The rudder servo mount is sized properly to accept the DS3421/S9650-sized servo, so installation for it is very easy.

Naturally, extensions are going to be required for this airplane for many of the servos. Most JR servos come with a standard lead length of 12 inches. Futaba’s servos appear to be of similar length. With that, the matrix of required extensions is below.

Aileron: 3” standard, right aileron to receiver / 6” standard, left aileron to receiver/ no extension required
Rudder: No extensions required
Elevator: 18” standard
ESC: 3” standard

Regardless of the fact that this is an electric airplane and that vibration is/should be nil, it is vital that permanent connections are secured by some physical means. I have always used 3/8” heat shrink tubing to secure connections such as this and have never had this method fail me. I have lost an airplane to connector keepers; furthermore they are bulky and are not the most streamlined system to use. Heat shrink is cheap, plentiful, secure, neat, lightweight, and barely larger than the connector itself is; virtually everything that a connector keeper is NOT. I heat shrunk the elevator servo extension, as well as the one to the ESC. These are two mission critical connections that WILL cause you to lose this airplane if they fail.

I also go one step further with the heat shrink and use it to color coordinate the connections for any temporary connections, such as ailerons. I have my own color coordination system worked out, but basically all one has to do is match the colors of the connectors and there is no way to plug anything up incorrectly.

To mount the receiver, I made a simple tray from 1/8” balsa sheet. I sized the tray such that it was large enough to support the entire receiver as well as the servo connectors. I radiused the outside corners, and took a balsa stripper to cut a 1/8” square gusset for the bottom of the tray to give a little more surface area to glue to. This tray was glued to the top of the wing tube and the rear side of the former just ahead of the tube.

I attached the receiver to this plate with some double-sided foam tape. I use the kind that is about 1/16-inch thick and black. This tape usually is shipped to hobby shops in bulk and sold as individual rolls. I believe Great Planes has this same tape available in single rolls as well. It’s by far the best foam tape I’ve used and once the adhesive takes a set, the parts will not move. It works well on porous surfaces (think wood), and so long as there isn’t dust covering the surface to prevent adhesion, this stuff will stick to pretty much anything. It’s not impossible to remove once applied, but I’ve found that I have to twist the part off of the mating surface to separate the bond of the tape, and then clean off of each surface respectively. For this reason, I tend to double the tape over itself to give a little better vibration isolation, as well as making it slightly easier to shear the layers should I need to remove a component.

I am also a huge proponent of tidy wiring and tend to go overboard with wire bundling in my airplanes and maintaining a sterile interior setup. This makes it easier to trace wires to specific servos, and also ensures that nothing moves, chafes, or is damaged by any internal linkages. With the Axiome, I was not able to go full-on lunatic with wire bundling, but I was able to route them together. The elevator and rudder servo extensions were routed together through the lightened gussets in the corners of the main “box” structure of the fuselage. Fishing the leads through the gussets is pretty easy with the right equipment- use a piece of inner nyrod, and tape the very end of the lead to the end of the nyrod and work your way through the fuselage. You’ll have to push the lead, as well as rotate the nyrod to be able to work it all the way through without it popping off, but the minute and a half you spend by yourself doing it sure beats the hour that you and someone else spend trying to use gravity to pull the lead through. Routing the leads through these gussets also keeps them free of the pull-pull cables.

One final thought regarding the routing of cables. I wanted to secure the ESC lead in the fuselage so that it would not move and fatigue any connections or solder joints from flopping all around the fuselage. Particularly in wooden airplanes, I will wrap a lead with clear cellophane tape and use a dab of medium CA to glue the lead to the airframe. This is much lighter and easier than the wire keepers that you can buy, costs literally nothing, and I always have a roll of cellophane tape and CA handy. I never have wire keepers handy.

Route your receiver antennas according to your manufacturer’s specifications. JR, Futaba, Airtronics, and Hitec all use similar antenna configurations. I did use the included RA01T remote telemetry antenna with my RG631B receiver, but routing the wiring for that was a non-issue. I don’t have any immediate plans to put telemetry in this airplane, however since it’s not a competition airplane, I may entertain it for demonstration purposes.

ELEVATOR JOINER

At this time, it’s a good idea to install the elevator joiner block into the elevator half that will contain the control horn, in my case the right elevator half. In addition to the elevator halves and joiner block, you’ll need the following:

Fine point pen
Covering iron
Rubbing alcohol
#11 blade
Adhesive (CA or epoxy)

Start off by taking your covering iron and removing and wrinkles on the joiner block, and sticking any loose covering down around the joiner pocket. Once satisfied, fully seat the joiner block into both elevator halves and trace around the outline of the elevator halves onto the joiner block and remove the block from the elevator halves. Cutting about 1/16” inside the lines you drew, remove the covering from the areas that will insert into the elevator halves. DO NOT REMOVE ANY COVERING FROM THE BEVELED FACE OF THE JOINER. Once the covering is removed, remove the pen marks with rubbing alcohol and wipe dry.

Test fit once more to ensure that you will be gluing the correct end of the joiner into the correct elevator half (it shouldn’t matter, but it never hurts to be absolutely sure). Once satisfied of a complete seat of the joiner, glue into place with your favorite adhesive. Being lazy, I simply used some thick CA to glue the joiner in place because I didn’t want to make a mess with epoxy. If it makes you feel better, by all means use epoxy, five minute should be a gracious plenty for the task. Monitor the joiner until the glue cures and you’ll be ready to move forward.

HINGING (PART I)

I split the hinging in half on this build. I didn’t want to permanently hinge the control surfaces for the control horn installation process, so I did most of the leg work ahead of time. The only materials you’ll need for this are a fresh bottle of thin CA (very important!), covering iron, and perhaps a fresh #11 blade. This is another area of the build that requires patience. Contrary to most people, I embrace the hinging process and actually look forward to it. There is something about it that is very therapeutic for me, and there is a huge benefit from doing a good job.

The first thing that you’ll want to do is to verify that the hinge slots are truly in the center of both surfaces. To check this, you’ll dry install all of the hinges and slide the control surfaces on their respective mating surface. Looking squarely from the trailing edge forward, you’ll sight down the entire surface from root to tip and verify that there is an even “reveal” from the control surface to its mate. If any of the hinge slots are off, adjust the slot as required. The flying surfaces on my airplane were perfect, but the bottom of the rudder was off about 1/32” on the fuselage side on my model. I adjusted the bottom two hinges accordingly and had no more issues. This may seem like an unnecessary step, however I can assure you that “knots” in the control surface hinging can cause you a lot of grief when trimming a model.

Next, take your covering iron, and carefully go over the hinge lines to remove any wrinkles and to ensure that the covering is well-adhered to the wood. Reinsert your hinges into the control surfaces halfway, and in open center of the hinge, carefully saturate the hinge with thin CA to lock it into that half of the control surface. There is a fine balance between “too much” and “not enough” glue. Because you are effectively sealing off the hinge from accepting more CA when you attach the control surface to its mate, it’s necessary to saturate that half of the hinge completely without having any CA seep outside of the control surface and wick into the rest of the hinge. This is where the fresh bottle of CA comes into play. I highly recommend buying a ½ oz bottle of thin for each build as it doesn’t take long for CA to thicken considerably after the bottle has been opened. It’s shocking to see how fast a fresh bottle of thin CA wicks into a hinge compared to a bottle that’s been open for even a week.

CONTROL HORN INSTALLATION

The control horns provided with this airplane are very nice aluminum threaded stud type that are a very close copy of the MK horns. I know this because I was a bit of a moron and sheared off the threaded portion of the elevator horn, but an MK horn I had stock of saved the day.
The only thing I can say that I’m not thrilled with on this airplane are these control horns. While they are incredibly nice, they are simply unnecessary and I fully believe that a flat G10 fiberglass blade control horn could have been used in its place. This would have been less expensive and easier for the end user to install. There is a fair bit of work that has to be done when installing these horns and I don’t believe the geometry of the horns is as good as it could be otherwise.

Nevertheless, the horns, as I said, are very high quality and perform very nicely. Note that I am writing the control horn installation prior to hinging. I did this on purpose as it’s easier to drill the hole and make all of the adjustments when you’re manipulating the control surface by itself, not attached to a much larger part. I’ll start the discussion with the ailerons as the linkage geometry for that is much more difficult to achieve than for the rudder and elevator, which are pretty much given. I’ll try to write this in as logical, and easy to follow path as I can. There is a lot of pertinent information that goes into laying out control horn geometry.
The tools and required equipment for this task are as follows:

Fine point pen
Low-tack masking tape
T-pin
Drafting square
Pin vise with 1/16” and 3/32” drill bits
Dremel
Thin music wire (36” preferably)
Thin CA
2.5mm hex driver
Threadlocker

The first piece of necessary information is the travel of the servo. At 100% travel, a servo travels more or less 45 degrees each way from center. At 150% ATV, the servo will travel 60 degrees. In a precision setup, we want the most resolution, hence the highest ATV value, possible for a given setup. I generally set my control surfaces up at 140% ATV to give myself a little buffer should I have some sub trim in my setup. The difference in rotation is negligible and I still use the 60 degree value as I’ll only be off a couple of degrees at most.

Secondly, we need to know the total travel of the control surface. The ailerons and elevators are beveled to achieve 30 degrees of total throw. For the ailerons, I’ll maximize the throw for now as I am pretty sure I’ll want all of it for snap rolls. I also used this because it keeps the math pretty simple…30 degrees is half of the 60 degrees of travel we get with the ATV set at 150%.

Next, we’ll need to know the distance from the hinge line to the attachment point of the linkage on the control horn. In our case for the Axiome, this distance is 32mm. Luckily, on the Hangar 9 arms, the outermost hole is 18mm, exactly half of the distance. This is shaping up to be pretty easy already.

I’ll take a break here to put in a plug for a device that I find infinitely useful for bench setup, the JR MatchMaker. This is a pretty cool little device that will modulate the pulse with output in accordance with the rotary pot on the side of the unit. It has two ports that allow for the pot to set the position of the servo, and two ports that cause the servos to sweep (speed can be adjusted with the same pot) continuously to “burn in” the brushes, if you’re so inclined. I find this gadget indispensable for finding the center position of a servo when setting up linkages, particularly in the wings. I also use it to rotate the servo arm to the full (150%) travel to find the limits for setting up the rest of the linkage. Often times, I have already installed the receiver in the airplane that I’m building by the time I get to linkage setup, and having a transmitter, receiver, and battery is a lot of stuff to have on the work bench at once. This takes place of the transmitter and receiver, and will work with any radio system to my knowledge as I believe the standard for center position for servos is 1.5ms.

Lastly, we’ll need to setup the geometry of the linkage so that we have the best mechanical advantage. I’ve always been taught to setup a linkage such that the pushrod is straight at extreme deflection. To do this, it means that the pushrod will be angled inward slightly when the servo is at neutral. This is easily accomplished. Once the servo arm has been set parallel with the hinge line, at the appropriate attachment hole (in my case, the outer hole) a short line perpendicular to the hinge line. Now rotate the servo to the extremes of its travel and project the location of the same attachment hole onto the wing. Connecting these two points should ideally provide you with a line parallel to the one you just drew. Project this line onto the aileron; this will be the centerline of your linkage.

We have to accept a little mechanical inaccuracy here as the diameter of the base of the horn will not allow it to be placed such that the attachment point for the clevis is exactly in the center of the hinge line. It’s close, but not perfect. We have to do the next best thing and get it as close as possible. I found the washer for the backside of the horn to be particularly useful to mark the center of the hole for the control horn bolt. Simply center on the line that you drew and align the front edge of the washer with the rear edge of the aileron bevel. Mark the perimeter of the washer as well as the center.

Because of the dihedral in the wing, one cannot simply measure the distance from the root or tip of the aileron to the centerline of the horn because it will be off by several degrees. The ailerons are the hardest surface to drill for the bolt because of this. The bolt needs to be perpendicular with the bottom of the wing spanwise, but also perpendicular with the center of the wing chord wise. See illustration below.

What I did with good success is to use a T pin to drive through the center of the bolt location on the bottom of the wing and carefully try to angle it so that it comes out of the top side of the aileron in the correct location. I was pretty accurate on the first try, at least with regard to remaining parallel with the wing spanwise. This was the more difficult measurement to hit anyway, so I was happy. I placed the washer on the top side of the wing with the edge of it aligned with the face of the bevel, the same as the bottom of the wing, and traced the perimeter and marked the center. I drove the T pin in through the top side of the wing in the center and it aligned with the rest of the hole that I pierced through, exiting dead center in the hole on the bottom side of the wing.
Satisfied, I took my pin vise with 1/16” bit and drilled through the top of the wing to the bottom satisfactorily. Finally, I opened this hole up with a 3/32” drill bit, drilled again from top to bottom, and use the provided bolt to tap the hole.

The problem you’re left with is the gap between the surface of the wing at the rear of the horn/washer because of the angled surface of the wing. To combat this, I took a Dremel and a 562 tile cutting bit and at a medium speed, went around the inside of the perimeter of the horn/washer and compressed the wood. I did not remove the covering for this, and the cutter didn’t tear the covering. After a test fit confirmed that the horn and washer would seat moderately well, I saturated the threads and the entire area underneath the horn and washer with thin CA. Once this set up, the area was rock hard, and I could install the horn. Please be sure to use Loctite on the bolt so that it doesn’t loosen over time.

The rudder and elevator are quite a bit easier, mostly because they are symmetrical. To measure the location of the horn for the elevator, I simply placed the washer in the corner with the edge of the washer aligned (again) with the face of the bevel and gave myself about a 2mm margin between the remaining two edges of the elevator and the edge of the washer. This distance more or less (within one degree) paralleled the fuselage side. I measured the center location of the washer on the top side of the elevator and made a mark there. I inserted my T pin about halfway through the surface on one side, removed it, and started it through the other side. The two holes met, and I was able to get the T pin to make a straight pass through. For the rest of the installation, reference the aileron instructions.

Finally, the rudder horn installation is the easiest of them all. Temporarily install the rudder onto the fuselage and center it. I usually use two ¼” balsa sticks that are clamped together just aft of the trailing edge of the rudder and taped to the sides of the fuselage. Take a thin piece of music wire and carefully push it through the opening for the pull-pull cable exit and run it through the fuselage. Rest it on the rudder control horn (or in my case, in the groove for the servo wheel) and mark the location of the wire on the rudder. Proceed to install the horn as noted in the previous control surfaces. Once this is complete, you’re getting down to the final stages of completion.

HINGING (PART II)

The easy part of control surface hinging is next. For the ailerons and rudder, simply center the control surfaces on their mating surface, push tight up against one another and glue in place. A cursory check to ensure that the hinges are still centered is always a good idea, but all the difficult work has been done previously when you installed the hinges in the control surfaces. Once glued into place (and the glue has fully cured), flex the control surfaces back and forth a few times, and give them a slight tug to ensure that the hinges are tight.

Because the elevators have the joiner block to contend with, there are a few extra steps that are required to get your elevators hinged properly. You’ll begin by sliding both elevator halves onto their stabilizers. Push the elevator halves together fully so that the joiner block seats fully in the left elevator half. Center the elevator in between the tip blocks and tape the tips in place. Next, tape some sharpened carbon fiber rods to the inboard halves (angled so that they just meet past the trailing edge of the rudder, and are the same angle to each other) of the elevators to check alignment with one another. There is slight play in the slot for the elevator joiner, so it’s absolutely critical to align the halves with one another, otherwise you’ll never be able to pull a straight corner or keep the same line through a loop.

Once satisfied that alignment is possible, remove everything, mix up some 15-minute epoxy and reinstall the elevator halves as before, tape back into place, and monitor the alignment of the elevators as the epoxy cures. When solid, wick thin CA into the hinges, remove the tape and carbon rods and take a breather.

As you can probably tell by this long build log for an ARF, I don’t do things halfway. Even though there is little to no gap in the hinges, I still seal the top and bottom of the hinge lines to eliminate any possibilities of there being any air seepage when the surface is loaded. The added benefit is that your hinge lines have a much nicer appearance and will never have any gunk in them. I normally cut strips for the surfaces that are appropriately wide, and if I’m feeling extra crazy, I’ll even cut the strips with a taper. After the seals are cut, I will score them down the center (on the top side) with the back side of a very dull #11 blade. This will not cut through the covering in any way, but it makes it very easy to double back on itself to stick into the hinges. With the control surface deflected the opposite direction, seat the seal into the hinge line and iron into place with a trim iron. It takes a few airplanes to get the hang of it and be able to breeze through with no issues, but the process itself is very easy and lends itself to giving the airplane a very professional appearance, as well as working to eliminate many trimming issues.

LINKAGE SETUP

There isn’t much to note here on linkage setup. Again, all of the hard work has been done. Provided for the linkages are 2.5mm steel pushrods, ball links, and clevises. All of the linkages use M2 bolts for attachment, both the ball link to servo arm, and clevis to control horn, which is a really nice feature. Also nice are the use of nylon locknuts to secure the bolts in place instead of a plain hex nut. Since the servo arms for all of the linkages are already in place and adjusted properly, the actual linkage connection is a quick process.

Turn on the radio system to get the servos centered, and tape the control surfaces level with the flying surfaces. Assemble the linkages and install them. It’s pretty cut and dry for the ailerons and elevator, and there are no real tips that I can offer that make this job any simpler than it already is.

For the rudder pull-pull, I use the same fixture (balsa sticks) to center the rudder for the pull-pull installation as I did to locate the centerline for the rudder control horn. Because the included pull-pull cable is two pieces, I had to use my own cable. In the past, I’ve gone to outdoor retailers (Gander Mountain, Bass Pro Shops, etc.) to get 80 pound test coated stainless steel fishing leader in big spools for pennies on the dollar. Because Champaign, Illinois is more or less in the middle of nowhere, I don’t have any good outdoor provision stores local to me as I did in North Carolina, so I got a standard Du-Bro 4-40 pull-pull kit.

I start off by running the same piece of music wire used to demarcate the control horns through the fuselage. Once it exits at the rudder servo, I pull it out of the fuselage slightly, tack glue the end of the pull-pull cable to it, and finish pulling the cable through the fuselage, pulling more than double the length I’ll need through.

I then break the cable from the music wire, wrap the cable behind the set screw on the wheel, and reinsert the wire through the other cable exit in the fuselage as I did before. Once through the fuse at the rudder servo, I tack glue the cable again to the end of the music wire and pull the cable back out of the other end of the fuselage.

I then take some short lengths of solder, insert them through the holes on the sides of the wheel, wrap them around and twist them together to prevent the wire from coming out of the groove when swaging the ends.

I then power up the airplane, and head back to the rudder. After attaching the clevises to the control horns, I thread the included turnbuckles in about three turns; just enough to bite into the clevis. I don’t put a ton of pressure on the cables when I’m swaging the ends, just enough to remove all of the slack, so it’s imperative that you have the ability to adjust the cables to the proper tension. I’ve never been able to make a cable too tight during the swaging process.

Once both sides are swaged, thread the turnbuckles into the clevises to tension the pull-pull cables. Done!

FINAL DETAILS

There isn’t much left to do to the airplane at this point.

Propeller balance is of the utmost importance. At the very least, ensure that you spend adequate time balancing the propeller. Spinner balancing is nice, but if you don’t know how to balance the spinner and the propeller so that they work together, it’s best that you just focus on doing a good job balancing the propeller and leave the spinner alone.

Complete the tailwheel installation by threading the tiller arm into the collar on the tailwheel assembly. Use some blue threadlocker on this and tighten down well. Install the open end of the spring through the eyelet on the tiller arm, put slight tension on the spring, and mark the opposite end of the spring on the bottom of the rudder, centered. Using a 1/16” drill bit in a pin vise, drill a hole at this mark, thread the included screw in the hole to tap threads, harden the threads with some thin CA, and install the screw through the end of the spring to complete assembly.

Put some sticky-back Velcro on the battery tray and cut some battery straps to length. With all of the components in place, check the CG of the model. The recommended CG location in the manual of 142mm aft of the leading edge of the wing at the root is looks to be a safe starting point. There are tons of trimming charts and methods out there to trim out an airplane, so fine tune the CG when you fly the airplane. This is easily accomplished by moving the motor battery.

The kit includes some very nice adhesive-back graphics for the airplane. I have worked with B&E Graphix to provide a package of vinyl graphics for this airplane to include:

Aircraft logo
AMA Number
Pilot Name
CPLR Design Logo
F3A Unlimited Logo
Brand Logo of your choice

This is the standard package and is being offered through their website at www.bandegraphix.com. As you can see in the images at the beginning of the thread, I’ve purchased a few extra graphics to finish out the airplane, but overall it looks very nice!

Give everything a good once-over to ensure that all nuts and bolts are tight, all linkages are secure, and that there is no loose covering. Once all systems are go, all that’s left to do is fly!

FLYING

I had to make an emergency trip back home to North Carolina for my wife's family, and I brought the airplane down with me as we are on track to get shut out for flying weather in Illinois until about June or July. I got one flight in before dark yesterday and was very happy. I think it's got a lot of potential and was very solid in the turbulence we had yesterday. KE performance, as expected, was quite strong. I found the airplane to be a little nose heavy for my taste, and there was some roll coupling, but an indeterminate amount of pitch coupling. I think the airplane compares very favorably (more potential) than the Carbon-Z Splendor, with which I have considerable experience. I like it!

PARTING THOUGHTS

Overall, I think this airplane is a home run. My airplane ended up weighing 2236g empty, and 2794g RTF. I was hoping for a little lighter weight, but the airplane as tested from the manufacturer was likely with much smaller servos that don’t have the same performance that the servos installed do. I am interested to know what CPLR’s airplane weighs RTF, but at the end of the day, there is no way that this airplane would NOT be legal to fly at any AMA pattern event, nor will the couple of ounces of weight make an appreciable difference in the way that the airplane flies for most people.

The airplane is very high quality, and the finish job is top notch. The airplane is very accurately built and the small adjustments that were made during the build on my airplane (stab alignment, rudder hinge alignment) were very minor compared to many other aircraft in the market today. It’s hard for me to give an honest estimate of how long it’s taken me to build the airplane, but I can say this, I’ve spend more time writing this copy than I have building the airplane by far. The airplane obviously has a champion pedigree and I’ve watched the video of Christophe flying it over and over in patient anticipation of actually being able to get out and fly my airplane.

I only have two gripes with the airplane. First of all, I am not a huge fan of the control horns, as previously mentioned. Secondly, as a person with big hands, installing the wing bolts is an exercise in futility for me. Short of running a bolt through the wing tube, there really are no other options, so I’ve substituted the thumb bolts for slightly shorter M4 bolts that I use a cut-down hex driver to install.

I’d like to publically thank Mike Mueller and the rest of my sponsors, JR Americas, Thunder Power R/C and Castle Creations, as well as Aero-Model and B&E Graphix for their support and friendship over the years. Thanks to Christophe Paysant le-Roux for designing and licensing this cool little airplane, thank you to Winner’s Model for bringing it to life, and thank you all for reading this build thread. It’s been a lot of fun to put together and to document. I hope that this thread will help whoever buys this airplane to put it together with relative ease, and I hope that some of the tips and tricks that I’ve passed along will help you as much as they’ve helped me.

Until next time, blue skies and 10s!

I'm happy to announce that the plane is finally up for sale. Expected ship date is this Wednesday and Thursday. Sorry for the delay. We have a combo deal available for the plane listed:
http://www.f3aunlimited.com/webstore...ex&cPath=8_101
Thanks and have a great day. Mike
800 591 2875

Guys here are some comparison pictures of the motor combos available.
We have the Dualsky XM4255EA-8 motor an XC8018BAd 80Amp esc. Those match up to the new Dualsky XP40006ECO 6S (JST/XH) packs that we have to go along with them.
The other package is the Hacker A5014XS and the CC Ice 75 Lite or regular. This package pairs up with the Power Unlimited 4500 5S 35C packs in either JST/XH or TP balancers.
Tons of options avaiable. Some cheaper than the other. All will work great.
Here 's some pics. Thanks, Mike Muellerhttp://www.rcuniverse.com/forum/atta...mentid=1981130http://www.rcuniverse.com/forum/atta...mentid=1981131http://www.rcuniverse.com/forum/atta...mentid=1981132

The planes started shipping yesterday.
I will be showing it at the NSRCA booth in Toledo this weekend. Stop by and say Hi.
Mike

Anybody fly one of these yet? A flight report or two would be nice. Mike?

First one in the uk now has 50 flights on it and very much approved of to say the least.

Will try to get some photos /further comments from the pilot

If someone happens to have (or can take without too much bother) a photo that shows where the pull-pull cable exits under the stab, that would be most helpful. Thanks in advance!