Troy Newman

Well gentlemen, I had the opportunity to dig into my Focus Sport today. My experience with this model so far has been very good.

I do need to preface this thread with the fact this model is an advanced model. It is not intended for beginners at putting together advanced models. It has some techniques used that normal sport type pilots don't deal with in a day to day build of a model. The instructions are intended to get the point across but they are not intended to take you by the hand and do it for you. The idea behind my starting this build thread was to give an archive to folks that don't know how some things are done and how to do them. I am working independent of Piedmont models on this build, and I will always have some suggestions that may not coincide with the way the models prototype model was built. However I will say the way Dave Guerin does things in terms in installation and building techniques are proven, work and are effective. Dave's techniques just like some of mine have been developed over years of building competition models. I have been building and flying models that cost 10 times this models price tag. The planes I have been flying for the past few years are at the absolute top for quality of flying and build. The finish work is all painted models that weigh less than most film covered models. The idea behind this plane is provide excellent performance on a price tag that is not $2000-3000. With this in mind there will be some things that are not a absolute perfect fit, and not an absolute quality of a custom built model. This plane is not intended for that market. It is intended to go together fairly easy, be stong and straight, and fly well. If my Focus Sport flies as well as the prototype model I flew in early July the results will be a great 110 sized pattern model.

The purpose of this build thread is assembly a model that anyone can do on a budget and still get big time performance for a smaller plane both in size and price. So you will not hear me bashing anything about this plane. Instead you will hear solutions to problems if they come up. I remember buying a pattern kit for the first time. I got a 8.5-11 sheet of paper that showed me the size of the ailerons and elevators CG range and a few rough shapes to symbolize servos and engine mount. The idea was you had to do it your way. The task was daunting indeed. This model is extremely advanced in its detail compared to those days. I have read the manual a little and I have looked over the parts. If I can augment the manual I will. From the looks of it the bases are covered. There will likely be questions but I intend to figure it out and get things done. After looking it over I don't think we are going to have issues. 99% of it is self explanatory. I am going to try and follow the manual steps as much as possible. I think I could probably do it faster by just digging in and doing it as I know where things need to go and how its suppose to work. Not everyone in this forum has that level of experience and I understand that. The purpose of this thread is to promote pattern models and pattern flying. This is a no Bit-chin' area. If you feel you need to do that take it to another thread please.

So here we go....................

Troy Newman

First thing I did was un-pack about 10 days ago and looked the model over. I then sat the bits in the corner to finish my current project at the time. Today I cleaned up a little in the shop and pulled the bits together to get started.

Below is a photo of the hardware that comes with the kit. There is no pushrod linkage or clevis stuff. I like this it allows us to pick the best stuff for our application. The model does come with a Dave Brown Motor mount. 6-32 Bolts for the control horns, and the threaded links that go on those bolts. Tail wheel bracket and assembly is included, and the main landing gear is aluminum. Not the lightest for landing gear but is effective and keeps the costs down. This gear should be good for even beginners learning to land competition type models. I don't think the gear is going to be an issue at all. Main wheels and some bolts for axles are included. Motor mounting bolts and blind nuts to attach the thrust block to the firewall are also included.

The cowling, and canopy are painted and the match is good. A quick check shows the stripes line up but I have not spent any time trying to mount it. I just held the cowling on the nose and said looks good nuff'. We will get to the details of the components as they come up in this thread.

First thing was to get some weights.

Fuse - 19.1oz this is very light for the fuse assembly. The fuse is strong and built well. The choice of wood is good and the inside looks to have good space for equipment. The servo rails are installed. The landing gear plates are in with blind nuts already installed.

Fin and Rudder - 2.9oz Again very light. The rudder is pre-hinged and basically ready to glue to the fuse.

Canopy- 7.2oz A little on the heavy side for what is needed. The frame is wood and built strong. The paint work is good. The biggest problem is the glass work is pretty thick. The fiberglass portion of the canopy is probably a little over done, but I don't think you can save more than a couple ozs here anyways. Based on the overall weight of the model I think it will be light and these extra couple ounces will not be an issue. Its not ideal but I think its good. The canopy is not a brick its just a little on the heavier side of things.

Cowling - 3.7oz. Again the glass work is a little heavy but its not extreme. i don't think you could shave a full oz off this have still have it durable enough for the job. The paint work again looks pretty good. The color matching is excellent to the Ultracote.

Stab / Elevators - 4.7oz This is pre Hinged and ready to go. The stab is extremely well built. Its strong and stiff. It has a fairly thick airfoil compared to the early Focus I models. Dave has employed his knowledge form the Focus I and II evolution to this smaller version. I think the thicker stab does multiple things that are good and I'm very pleased to see the stab constructed this way on the model.

Right Wing - 11.0oz
Left Wing - 11.1oz
Ailerons pre-hinged and read to go. Like the stab and rudder the control surfaces already have hard points for the aileron control horns. Wing is about 780sq in and I think these panel weights are good. Of course a custom built wing can be lighter but these are not excessive.

Overall weight of the airframe. 59.7oz 3lbs 11.7oz. I think this will end up being about 8.25lb model which will be excellent performance on the YS 110.


Next comes the start of the build...............

Troy Newman

The model has been sitting out of the packaging bags for about 10 days. So first things first I took out my covering iron and heat gun and went to getting the covering tight again. I live in Phoenix AZ so the air is very dry. I find that when models come to my climate the wood will dry out a bit and since this moister is not present…the covering will sag a little. The Focus Sport had a few wrinkles…but overall it was still in really good shape. This is even though its been in my garage during that time. For those that have not been to AZ in the summer time, our low temps are around 90-95degs with Highs above 100deg F almost every single day. This past week has been near 105-110deg F with lows being about 88 as the lowest temp. My Garage has no AC yet so the model was subjected to similar temps for the last week.

I place my H9 covering iron inside a cotton tube sock. This gives a soft surface to eliminate scratching and digging into the balsa surfaces. This also gives an even heat that works well to get stubborn areas.

I then used a brand new #11 X-acto blade to remove the covering from those areas on the fuse where the covering has not been cut away. I then ironed the covering around the edges and got everything ready to go.

Below is a before and after photos

Troy Newman

Construction starts with the Wing installation. The wing tube is 23 inches long. The instructions call for it to be centered in the fuse. Once I did this the result was 9 5/16” each side of the fuse. I then marked the wing tube with a Sharpie like the instructions call for. The tube was then inserted into the wing panels to make sure the tube would go all the way in. The idea is we need to get past the false rib that is installed in the wing. I slide the tube inside the wing socket and at the end the socket was a little tight. You want it to be fairly tight but not really hard to get on and off. So I took a ¾” wooden dowel with 100 grit paper attached. The photo below shows this tool. I used this to open the socket or sleeve up just a little. The aluminum tubes and fiberglass or phenolic sleeves can always vary little in diameter. This is common and usually only takes a slight amount of work to fix it up. About 30 secs of sanding per wing panel allowed the tube to pass directly to the wooden end cap at the end of each wings socket. Just use a plunger action in and out with the sanding tool inside the socket. Be careful not to bang the wooden end cap you might damage it or the wing if you get too rough. The idea is lightly sand the inside of the socket to allow for a good tube fit. You want it tight but not extremely difficult to insert.


So I slide the aluminum tube inside the panel of each wing it comes up about ¼” too long on each side. See the photos below of the marked tube inserted.

In this case I need to cut aluminum tube off a little to get it to fit. I need at least ½” shorter length. Don’t cut anything yet….go to the next step. I have in the next post.

Troy Newman

We need to find out where the hard points are for the wing retention screws. When I was taking care of the few wrinkles in the covering I found the hard point. This is easy to see when you heat up the covering in the area. The dowel hard points are installed on top of the wing at approximately 8 ½ inches from the wing root. The hard point is on the edge of the yellow strip and red leading of the wing. Below is a photo where I marked this location with a Sharpie marker. This will prove easy to find later with the Sharpie circle around it. The Sharpie will wipe off with Rubbing Alcohol so it’s the best marker for the task. Mark the hard point as I don’t drill the retention bolt holes until later on. I know the instructions say to drill it but… Its usually one of the last things I do. I don’t want to have screws around in the panel to rub on the other wing panel. This can cause some hangar rash…so I usually drill and tap the holes later on. This is important step so don’t forget it….but it can be done at the end.

Knowing the hard point is 8.5” into each panel and I know that 9-5/16” of tube is about ¼” too long. We can safely cut the wing tube shorter by about ½” to 5/8” to use the max length of tube and ensure the tube is passing through the false rib installed in the wing. This also gives plenty of meat for the wing retention screw in the aluminum tube.

I pushed a small thin section of music wire into each wing panel. About ½” in front of the wing tube location. I wanted to find the location of the false rib. In both panels this location was 7.5” from the root of the wing. Therefore we know the rib location is 7.5” and the hard point is 8.5’ in from the root of the wing panel. This isn’t a task that everyone needs to do but I wanted to make sure the tube was going through the rib. I also wanted to check the relationship of the hard point to the false rib. This was a little of CYA and since I didn’t build the wing panel I was not sure where the rib was located. This test told me what I needed and confirmed that Dave and Piedmont Models did their homework. So the information is for those of you that are concerned….The rib is there and out at 7.5 inches from the root.

I then proceeded to cut the wing tube shorter by 5/8”. This will give me just a little bit 1/8” shorter tube than needed to hit the wooden end caps. Once cut I used my belt sander to clean up the edge of the tube. If you don't have a bend sander A block with 100 grit paper will work well. You just want to clean up the burr on the end of the tube where it was cut. Use an x-acto knife on the inside edge of the tube to clean any burr that may be present. Be careful not to cut yourself on this burr. The idea is to sand it to eliminate sharp edges. These can damage the sockets in the fuse or wing panels, or cut your finger. I know I know...I'm not trying to mother any of you...just that is seems to reason somebody would cut their finger on the aluminum tube.

Important:

every wing probably has a slightly different depth for the end caps. If you have trouble getting the tube to go in about 9” into each panel you need to look inside with a flashlight and see if some glue is blocking it. I would say the absolute shortest you would want is 8.75” but you may be able to use the full tube. Without cutting it. It all depends on the end caps. Just double chekc the location of your hard points and the depth of the end caps. I feel if you are past the hard points then you are safely past the false ribs.

I cut the wing tube 5/8" and the result was a perfect fit. Next is the setup of the wing adjusters and the incidence of the wing. That will have to wait until tomorrow.

dreadnaut

My Feedback: (5)

Troy, it sounds like you used a hacksaw to cut the tube. I like to use a pipe cutter. The advantages are that it does not leave a burr on the outside, thought you should still use an w-acto blade to clean up the inside. A belt sander is not needed. It also makes a REALY square cut, and the end winds up being rounded inward, which makes it easier to insert.

Dave.

Zippi

My Feedback: (10)

Thanks to troy, I found the hard points for the wings after I shrunk the covering. They were hard to see with the covering loose.

Troy Newman

Dreadnaut,

actually I used my band saw. But the tubing cutter will work excellent for the task. I don't have one but a hacksaw or band saw with a metal cutting blade works well.


While working with the wing and setting it up for the fit above, I noticed that the wing tube was a little loose in the fuse socket. As we found above the fit was tight in the wing panels, however in the fuse section it had a small amount of play. There are multiple ways to fix this problem. You could use a little medium CA to build up the center section of the wing tube diameter. You could use the CA inside the socket to make its Inside diameter smaller. The difference in diameter is very slight. By trying to do it inside the socket you risk screwing it up and making the socket too small diameter. This will give you a tough time getting it back to where the tube will go in if you are not careful. The CA thing works and is pretty durable but it can make a mess and you usually get it too much build and have to sand it back down a little. Another option that I use on Carbon Fiber tubes on my Oxai Models is Clear Finger nail polish. You can paint it on and then use your finger to spread the thin layer of nail polish. Since finger nail polish comes off really easy with Acetone the clean up to your fingers is easy. However in this case the wing tube is aluminum and the polish or the CA doesn’t stick well to the tube. I don’t want to risk making work for myself with the CA thing inside the fuse socket section. My method of choice is Scotch tape. Two single layer diagonal wraps one from each direction was enough to tighten the tube in the fuse socket. The scotch tape is easy to replace and will actually last a long time. Below is a photo of the work. Notice the tape is only where needed in the center section of the tube. Since the tube fit in the wing panels was good after my sanding job, I don’t want to add thickness out where the panels slide on. If your fuse center section is too tight a fit use that sanding dowel from above and it will take care of it very quickly. Like I said you want a snug fit, just don’t let it slide on and off really easily. You want a slight amount of friction but not a hard push to install it.

Troy Newman

Following the instructions for the Model takes us to the Incidence settings on the main Wing.

Now I want to talk a little about wing adjustments. Gator RC wing adjusters are included in the kit. These are for tuning and not for setting the incidence. What we are going to do is set the incidence per the instructions at 0.5degs positive with the reference shown in the manual. I’ll get into some details about this and the reference as that is important. For now we need to prepare the wing and the adjusters for this critical step.

The wings come with holes “pre-drilled” in the wing roots to accept the small phenolic sockets the adjuster pins slide into. There are front and rear adjuster holes on each wing panel. They are located aprox 5-6 inches forward and aft of the wing tube. The phenolic tubes provide a hard bearing surface so the anti-rotation pin does not wear inside the wing panel. In our case the anti-rotation pin is actually adjustable using the cool little adjusters from Gator RC. The phenolic sockets will guide and hold the pin while the wing is installed and flying. It is important to get them installed well. I use medium CA to hold the phenolic sockets in the wing. To help the CA glue bond to the socket material I sand the outside of phenolic sockets with 100grit paper. This removes any type of glaze or waxy substance on the outside of the sockets and gives the glue some scratches to bite into.

Next is to trial fit the adjuster pins inside the sockets. Sometimes these sockets can have a slightly undersized I.D. This is not common but can happen. Also the adjuster pins have a molding flashing on the end. I clean these up with my 100 grit paper as per the photo below. With the flashings cleaned up and the phenolic sockets sanded they are ready for install…………..

Troy Newman

The pre-drilled holes look to have some plywood or hard balsa as a backing support to the balsa wood root rib. On my model these plywood backing plates had a slightly undersized hole to fit the phenolic sockets. In looking at it we have two choices try to force the sockets in place which might work….or it could crush the phenolic socket. Since I’m not a sledge hammer mechanic I grabbed a small round file and slowly opened the hole in the wing panel. A dremel tool could work also just be careful you don’t over do your work. You want a tight fit just not a “Grab the Hammer” fit. This took a little time about 2-3 mins per socket to get a good snug fit. I would rather have a critical fit like this being undersized and allow me to open it up to the perfect fit rather than have the hole too large.

Once I have them trial fit you can use a small section of music wire with a “L” bent in the end to help you get the socket back out after the trial fit and before gluing.

Once you have the sockets fit properly its time to glue them. Important to not get CA inside the sockets as this will cause problems for the adjuster pin inserted in the socket. Also a little problem you could run into is as you are inserting the sockets the CA glue could kick off and now the socket is only ½ way in the wing panel. A little trick is to have a large wooden block. Here is one of my sanding blocks. When pushing the sockets in place you want them flush with the root rib but not recessed. I use this flat sanding block (1” thick MDF or particle board) to push and persuade the socket in place. Do the sockets one at time to prevent the glue from kicking off.

I carefully put a small amount of medium CA in the hole and then get the socket started in the hole. A small amount of CA around the outside of the socket…then immediately push the socket into the wing. If the socket stops you need to act quickly a little tap from the block will push it flush with the root rib. Once flush immediately wipe any excess CA off the root rib.

Use an x-acto #11 blade to clean the inside of the edge of the socket. Sometimes there is a small burr or a little bit of CA that gets on the edge. Once the CA kicks off trial fit your adjuster pins again in the phenolic sockets. If you screwed up and got glue inside now is the time to fix it. Don’t worry I have done it before. A round file will do the trick. Just takes a little time. You want the adjuster pins to be a slip fit with very little friction but you don’t want them sloppy at all.

Wing now has the sockets installed and its time to get the fuse ready for the adjuster install………..

Troy Newman

The sockets for the adjuster pins is now complete in the wing panels and its time to get the fuse ready for adjuster install and incidence setting on the main wing.

I installed the wing tube and both wings on the fuse. I then tried to slide the adjusters through the holes in the fuse into the sockets. On the left rear and the right front adjusters, the holes in the fuse were not completely open to allow insertion of the adjuster pins.

This is an easy fix. Just use a small file or dremel tool to open the slot in the proper direction. At this point don’t worry about making the holes longer top to bottom just the fore and aft wide of the slot to allow the adjuster to insert.

As you can see the front one is just a tight fit and only needs a very small amount of sanding. The rear hole is a little more obstructed. Its about 1/16”. So its not much but it needs a little work to make things fit up correctly. Overall it tool me longer to find my dremel than it did to perform the work.

I widened the slot and now all 4 adjusters will slide into the phenolic sockets in the wings. Mind you I have not looked at all at the incidence or the vertical size of the holes. We will get to that in a few more steps right now keep the dremel handy as we may need it to get the incidence in the right spot. Not sure yet, as I have not gotten there.

For now trial fit the wings and all 4 adjusters like in the photo below

Troy Newman

Wow

Great detail as usual. Thanks Troy for your time on this project.

Allen

Zippi

My Feedback: (10)

This is my first Pattern plane in over 20 years and things have really changed. Troy is putting every little detail into play and the experience really shows. I keep wanting to jump ahead and get things going but I just might tag along with Troy.

Columbus Ron

Troy,

I noticed that the Sport Focus does not have cheek cowls but the Focus II does. I've got an Impulse without cheek cowls and my 160DZ overheats. Do you think this will be a problem with the Sport Focus. Otherwise, it looks like a great plane. I may get one.

Ron

Ryan Smith

My Feedback: (25)

Ron,

It hasn't been a problem thus far with the ones Dave has had. Cheek inlets can actually make your motor run hotter if you're not careful with ducting.

Troy Newman

Ron,

your DZ is not overheating because you don't have cheek inlets. You probably have other issues going on like ducting issues or perhaps not enough exit air.

First off on the DZ engines you have to have direct air flow to the pump. You need to get fresg clean air to the pump. If you have fresh clean air to the pump and still having issues look to exit air area. You are going to need 3 times the exit air area to the inlet air area.

Next is look at the engine inside the cowl. Can the air snake around the engine without going through the pump/pushrod tubes, and then through the fins on the head. If you are having issues you need to direct the air to the head. We use foam rubber like that in the YS engine box to block off the edges so that the air has to go through the fins on the engine.

We can discuss some ideas for ducting. I live in PHX AZ and its hot here in the summer. In fact it was over 100degs F today.. so that being the case ducting is very important on my models. If you are interested we can do another thread regarding this issue.

In this case there are no cheek inlets on the focus sport. and there are not cheeks for that matter. I don't expect issues with overheating but we will deal with those possibilities when the time comes.

Troy

wildnloose

Hey Troy,

I have a ys 1.40 sport looking for a home. What do you think about putting this engine in this plane??

Sorry about getting off track a little, but I need to spend the money quick before my wife finds out about it....

You can pm me if you like.

Thanks
Wild

jetmech43

My Feedback: (9)

I think the YS 140 will more suited to the Focus 2

Troy Newman

I don't recommend the YS 140 Sport for this model. You could do it but the model is designed around an engine that is about 6oz lighter than the 140 Sport. That compared with a model that is probably going to be under 8.5lbs I think the performance would be too much for the model. Too Much power like that would make flying the precision difficult. One of the most difficult things to master in Precision flying is good management of the throttle. If you are so over powered that you never go above 1/2 power its very difficult to control the model.

This combined with the extra weight...stick a good YS 110 in it. If you want a Focus for your 140 Sport get a Focus 2. The ARC versions are very reasonable and you have a full size pattern plane. The idea here is to do it and optimize things around this slightly smaller model.

Troy

Troy Newman

We are not quite ready for the incidence setting on the wing. We need to prepare the adjusters. First take a look at one of these little gadgets. There is a jack screw that adjusts the height of a pin. The pin will act as an anti rotation pin for your wing panel. Since the screw can move the pin up and down this will change the angle on the wing panel. First thing first, look over the adjusters. Make sure they are in the center of their travel. There have been times more than one guy has installed the adjuster and it was only 1 turn of the screw away from a end of adjustment on one side. We want to make sure the pins are centered up on the jack screws. This gives us the max movement both up and down.

Tack Glue the adjuster frame to the plywood adjuster plates. I used the bolts to align the holes in the plates to the frame of the adjuster. Medium CA works for this task well.
This needs to be done for all 4 adjusters. Once the plates are glued to the adjuster frames remove the screws. Be careful with these assemblies the adjuster is on tack glued to the plywood.

Troy Newman

Wing Incidence.............

We have spent a little time getting the model ready to set the incidence and install the adjusters on the main wing. The next step is to insure we get it set properly. The adjusters are for fine tuning not setting the incidence. So we want to get them installed with the 0.5 deg Positive already there to give maximum adjustment in either direction.

Dave Guerin in designing the Focus Sport gave us the reference or flying line for this model. In the manual it says block the tail up 1" off the surface. To do this we need a flat table. The base of the fuse at the tail is then placed on a 1" block of wood. The front of the fuse is allowed to rest on our flat table. This is our reference for the flying line location. If you were to stand way back and look at the model in this configuration the model would appear to be level as if it was flying this way. What we have now is the table top is flat and the Fuse is "flying" parallel to this surface.

I used a digital level to make sure my table is level with the world. If using an incidence meter like the Robart or the Hangar 9 these are basically like a builder’s level. They work with gravity and they reference what is level and flat with the earth. To use this type of meter you need to have your reference in our case the table also level with the world. If your table has a incline of 1/2 deg and then you use an incidence meter to set the incidence now you could have the wing possibly 0 deg or 1 deg to the model as your reference on the model was not the same as the reference for the meter. All we care about is the reference of the wing to the model or its Flying line. We are trying to set things relative to the fuse flying line...not to the earth. The digital levels and incidence meters reference the earth not your table. There are a couple solutions shim the table to zero with the earth...or just use the angle of the table and add 1/2 deg positive to that....

This can get complicated and if your head is not spinning yet....I'm going to make easier on you but we need to understand what the meter is referencing, and what we are trying to set the wing in reference too. Please just hold on through this discussion and I'll give you an easy solution to this variable, optional, anything can affect its reading. Our goal is to try and get the wing as accurately set to 0.5degs positive as we can. I just want you understand that it can be trickier than just making the Robart meter say 0.5egs. The designer of the model tells us that the model should trim out really close to this 0.5degs in relation to that flying line reference so we need to get an easy way to reference that flying line.

If you have a flat table and block the tail of the fuse up by 1” you could use principles of geometry to measure from the table top (if the table is flat) If the centerline of the Leading edge of the wing is the same distance off the table as the Trailing edge of the wing. If the wing is set with the LE and TE distances the same from the table surface then the wing is at zero or parallel to the flying reference line. This is good info to store in our brain. What else is a reference we can use? After shimming my table to be zero to the earth I placed a digital level on the canopy frame. With the tail blocked up that 1” per the designer and the table at zero deg to the earth….The canopy frame is also zero deg to the earth. What we just found was that the canopy line is also parallel to this Flying line too. We want to get the wing 0.5degs Positive to this Canopy frame reference. Now we are getting somewhere. Let’s get to the different ways to set this up now that we know the references and how we are going to be setting the wing in relation to these references.

Setup the model as shown in the manual for the model and you also need some additional items. These are shown in the photos below.

Foam Blocks to help make the wing stable and fine tune the setting while making your adjustments and measurements.

1” wood block to shim the tail of the model off the table.

Some weight to hold the fuse stable while making your changes and adjustments. Small sand bags or bean bags will work. I have a couple of bags of Pinto beans that works great too. In this case I used a sheave from an air handler. A small 5lb weight would work also.

Block the fuse up like shown in the photos and make sure the entire model is stable. Then we can get onto the next step.


Also a photo of my table before it was leveled up to the world. It was off by 0.2degs becasue the slope on the floor. In AZ we have concrete floors and this one is not level.

Troy Newman

Set you table level to the earth and have a flat table. The 1” block under the tail and the using a incidence meter can get set to your 0.5degs positive. The incidence meters are tough to use. These meters are ok but its tough to get accurate settings. You can get the two sides the same within reason and then we have the adjusters to tweak it when we are trimming it. The problem I have is the Incidence meters are difficult to repeat values and the angles we are trying to read are so small its tough to get accurate settings. This use of incidence meters is OK and modelers have done it for years. There are people that have made mods using digital levels, there are other people that have build jigs that hold the model and allow the builder to make more repeatable readings and so on….

This is the method I actually used to set the wing up on my Focus Sport. This one is a little easier to get accurate results. To me accurate and repeatable results are important. We are going to fly it, and trim it so the numbers don’t really matter in the end. But I want to give the designer the edge on this one. I have not built this model before he has. Oh and by the way He has built and designed many championship level models. In my book if Dave says its ½ deg positive that is where I’m going to start. My goal is to get this model as good as possible I don’t need to chase my tail trying to re-think what he already learned with the design.

Troy Newman

Alternate method that I feel is more accurate:


I’m an Engineer and I’m not afraid of numbers and measuring things. I’m trying to get the most accurate way with as little technology as possible. This will give use the easiest way to do it. I know that my table is flat. So I don’t really care if its level to the world….Use the table as the reference in this step. This will also help when I set the stab incidence. I mark the center of the Leading edge and Trailing edge of the wing at the roots like the photos below.

I’m going to now set the wing using some foam blocks to hold it while making adjustments…I want to get a zero reference. I want the wing parallel to this flying line. To get this zero setting this center LE and TE mark would be the exact same height off my flat table right? You can use a metal ruler trying to squint at the numbers and trying to get it accurate to 1/64” or better. I have a better idea. I don’t really care what the number is just that the height from the table to the LE mark and the TE marks are the same off the table. I use the device below. It’s a height gauge and doesn’t tell me how high the mark is off the table but it allows me to compare marks from the same reference. In this case the reference is the flat table. A height gauge will be a home made tool what work well and you don’t need to try reading little tiny numbers from a ruler. Remember we need to set the front and back of both wings. This means 4 different measurements need to be the same. If I use a Height gauge off the surface of the table I can set the distance and then compare all 4 numbers to the same reference line, the table top. Here is a photo of the height gauge I made. Its just a block of wood with a ¼-20 all thread piece installed in it. I now have another block with a ¼” hole drilled in it and I drilled and installed a length of music wire that was ground to fine point. This is the pointer. A pair of ¼-20 wing nuts from the hardware store makes adjustment possible. When I get the Height set properly, I can lock down the wing nuts and the music wire pointer will be the same height off the table at all locations. This gets us to the same height for the LE and TE marks. Once I set the wing so these marks are equal distance from the table I can use a fine point sharpie to make the fuse. This will be my Zero reference on the fuse. By the way this line should also be parallel to the canopy frame. So you could measure down from the canopy from instead of up from the table.

When the wing is on the tube likely it will not stay where you want while trying to make your measurements. I use some small foam blocks like it the photos below. Adjust the wing by pushing the foam block further under the wing…The air foil curvature will slowly adjust the angle of the wing as you push the foam block further in or pull it out. This makes things stable.

Before we get too far along this path we need to realize one thing. We need ½ deg positive to this table reference line not ZERO. That’s an easy one. Remember your trigonometry teacher talking about SIN COS, and TAN of angles. Now is the opportunity to use that useless information. I’m not going to go through the drivel of the math. If you want to know ask and I’ll do it offline…My guess is you either know how to do it or don’t care. If you don’t care that’s cool I’m going to do it for you and determine numbers we need to use. The idea is we want to lower the trailing edge a certain distance in order to get the wing ½ deg positive in reference to the zero flying line which is parallel to our table. . I want to find a location to make a new mark on the fuse that is the ½ deg line at the trailing edge of the wing. If you crank out the math….The Trailing edge of the wing is 10 1/8” from the center of the tube. So using the trigonometry I determined a ½ deg change over this distance of 10.125” is 0.0884”. I then try to convert that to a number we can measure with a ruler. It’s a little tough but 3/32” is 0.0938”. Reverse the math a little and we find that a 3/32” lower trailing edge gives us the wing at 0.53degs. This is darn close. You are not going to get closer using a Robart meter in fact I doubt you can get this close. So I remove my wings and Mark the fuse with a tick mark that is 3/32 below the “Zero” mark at the Trailing edge right?

Let me make it even easier. 3/32” is a pretty standard and common size for wood around a modelers shop. So I used a small scrap of 3/32” balsa under the Height gauge. I used it under the gauge when I set my zero lines for reference. Then to get the location of the Trailing Edge after I have the Height gauge set for the zero location I just remove the balsa scrap. Now I can lower the TE of the wing to my Pointer location. The Pointer if set properly at the equal distance for LE and TE center lines will then be exactly 3/32” lower when you remove the 3/32” balsa scrap. Viola it’s easy. Slide your foam block out and lower the TE of the wing until it comes to the pointer. This is your ½ deg positive incidence. Actually is 0.53degs but its closer than any other method I can find.


This wing is now set very close to the 0.5degs the designer wanted. We want to tweak it when trimming the model we can as the adjusters allow fine tuning. This is a starting point. We have the wing as close to the design starting point as accurately as we could.

Troy Newman

Notice in this photo above I have two marks the top mark is the"zero" mark and then I removed the 3/32" balsa scrap from below my height gauge and I have a new mark that is 3/32" below when lined up with the TE centerline the wing is at the 0.5deg positive incidence. This mark I show as lower in the photo. I marked it with a dot to show myself which one to use for the 0.5 deg line

Troy Newman

The adjusters were tack glued to the plywood adjuster blocks.. The adjuster just slides into the wing socket through the fuse. Make sure your Wing TE is still on the pointer or mark for the 0.5deg incidence angle. The adjuster installs with the Screw heads pointing up. Make sure the adjuster is vertical. You don’t want the pin moving forward and back at the same time its moving vertically.

CA glue the adjuster-plate assembly into the fuse. Use Medium CA This way you can use a ball driver to make adjustments. Only do this to the rear adjusters. This will allow you to fix a mistake easier than doing all 4 at once. Once we are sure everything is correct and back on the marks you can do the front adjusters.

I remove the wing panels after I have the rear adjuster glued in on both sides. The next step it to install screws to hold the adjusters to the fuse. Using a Pin vice and a small drill bit I drilled from the inside of the fuse through the adjuster holes to the outside of the fuse. It’s a pretty easy task. Next is use a drill and enlarge the hole from the small bit to that which can take a 4-40 bolt. My machinist’s handbook says that drill bit is a #33 0.113” diameter. So its about 1 size smaller than 1/8” drill.


Be careful at the adjusters are only tack glued to the plates. Once you have the holes drilled look at the adjuster’s position in the fuse slot. Is there enough room for adjustment? In the case of the photo below there is plenty of room above the adjuster pin below is only about 1/8”. This is enough room. Our settings above told us that 3/32” is about 1/2 deg. This means that since the adjuster is near the Trailing edge 1/8” vertical movement gives us well over 1 deg total positive if we need it. I know we won’t need it but its there in case we make major changes. If your model doesn’t allow for 1/8” movement in the adjuster pin up and down….after the screw holes are drilled pop the adjuster off the plate and use a dremel to open up the slot in the fuse to get the desired travel of the adjuster if its needed. You also want a little gap on the sides of the pin. It does not need to be much but a small gap on the side of the pin is good. Install the screws and hex nuts for to hold the adjusters in place. I use a small drop of medium CA on the screw to hold the hex nut from backing off the screw under vibration. Don’t get messy with the CA little drop will do the trick. If you choose some Blue lock tite will also work.