isf2008

I have been a fan of the Telemaster for over 25 years, having had 3 of them. The most recent Telemaster is a 40 size kit that I built in 2008. While it looks a little ratty these days, this airplane is still going strong with hundreds of flights on it. When Hobby Lobby introduced the new 12' Laser-cut Telemaster last fall Ithought that this planewould be a worthy successor to the40 size plane in the hanger. A recent sale on the Hobby Lobby website made the decision to acquire the kit easy.Searching on the internet revealed little aboutthis kit, so I thought that I would share my building experiencesin the form of a building log.

The mission profile for this airplane is fun flying with the ability to haul cargo or a camerain the bomb bay and perhaps tow gliders. While aDLE 55 or similar engine is probably ample power for this plane (one of the prototypes was powered by an OS55 gas engine) I wanted a little bit more zipgiven the glider towingsegment of the mission profile.DLE's new DLE85 looked like it would fit the bill, and somecalculationssuggested that with a 26x8 prop it would hover at 40% power, even given the slight weight penalty of this engine relative to a DLE55 with Pitts muffler.All-up weight is targeted at around 32 lbs. My 40 size Telemaster is not hardcore acrobatic, but it has its tricks, like flying backwards in a slight headwind with full crow.The DLE 85 on the 12 footer will only add to the fun. Hobby Lobby advertises that the airframe of the new12' kit isa lotstronger compared to the previous edition of the kit,so I'm not concerned with overpowering the airplane.

Anyways - to the build!

About a week ago FedEx dropped off a rather large and heavy box (35lbs) at the front door. Opening the box revealed a ton of laser-cut balsa and ply, some sheet material and sticks, anda rather large aluminum landing gear. A hardware packwas also included, along with 4 sheets of full-size plans. The vast majority of the parts are laser-cut, and there areover 600 parts on 85 laser-cut sheets.The laser-cutting is outstanding, and some of the bestI've seen in a kit.The hardware pack is comprehensive, requiring that you supply the regular items like wheels, fuel tank and control linkages. Attached are a couple of pictures...

In this post I'm generally going to follow the construction sequence givenin the manual. There are also some unique construction methods used, and I'll detail those as I go.Construction starts with the horizontal stab, and the next post will begin with that.

Enjoy!

t-max97

My Feedback: (9)

Awesome, cant wait to see it!

soarrich

My Feedback: (98)

80~85cc is about max for a single cylinder two-stroke in RC, above that there's too much shaking going on. I would not use a cheap Chinese 85cc engine probably too much shaking, a 80cc ZDZ or 85cc DA you might get away with, but not a under-engineered Chinese 85cc. With the Chinese you are always a Beta tester.[:'(] 80~100cc twin would be a better choice IMHO.

FlyerInOKC

My Feedback: (6)

Nice kit I see they even included the wheels!

isf2008

Building the horizontal stab:

I have attached some pictures of the horizontal stab during construction. Finding all the parts proved to take some time. Luckily the manual has a cross-reference chart that gives the part number and the sheet that it is on. It is well worth the effort to sort the sheets by number so parts can easily be found. The laser-cut parts are very crisp, and come out of the carrier sheet with light pressure, only sometimes requiring a knife. The little securing tabs cleaned up easily with an emery board. Also of note is that there is almost no

- The stab is built on a plate made up of laser-cut parts and a basswood spar. The first task is to assemble all this over the plans. The spar is spliced from two pieces, and a miter gauge is provided to trace the miter onto the parts. Parts are overlapped, and a little CA on the scrap ends helps keep the two sticks aligned while cutting.
- The trailing edge, also laser-cut, is then added. The TE has all the rib locating slots and hinge pockets laser-cut into it. As well, it has tabs that locate it in the stab plate.
- Ribs follow. All the parts fit very well with no trimming or adjustment needed. There are lots of notches and tabs to ensure the parts are aligned correctly.
- Sheer webs come next. I butted the sheer webs on the outboard rib of each bay for additional strength and to help keep the rib square. I also used some scrap material to fill in the gaps in the shear web in the root bay. Probably not necessary, but hey, why not!
- The top spar was added next.
- The leading edge was added last. This is the first little glitch - the plans and manual call for a 48" piece of 1/2" x 3/4" balsa, but two pieces of 1/2" x 1" balsa were supplied instead. I ripped the 1/2" x 1" sticks down to 1/2" x 5/8" with my Proxxon table saw (a very handy tool) and then spliced them together. A bevel was added to help speed the shaping process.
- Hinge pockets are laser-cut basswood and slot into the TE and the rear of the stab plate.
- Balsa covers go on each side of the hinge pocket.Little holes are cut in each hinge pocket cover to let air out when gluing in the hinges. Now that's thinking! Also, the hinge pockets are the exact depth required to seat the hinges.

That's it for the basic stab construction. Next post will cover installing the tips.

isf2008

FlyerInOKC:
The wheels did not come with the kit - I had thrown them in the box and they were there when the picture was taken. The hardware pack is comprehensive - everything is included except for wheels, control linkages and fuel system.

isf2008

Stabilizer tip build:

I installed the stab tips today - very easy to do. The tips are laser cut, as are the three middle gussets. Two pieces of triangle stock make up the ends.

- The instructions tell you to bevel the bottom of the tips at 45 degrees. I traced a line 1/8" up from the bottom as a guide, then glued the gussets and end stock to this line. Hey Hobby Lobby - how about a laser etched reference line for the bevel just like the locating lines for the gussets?
- Once the glue was dry, a few passes of the sanding block made a perfect bevel.
- Tips were glued on and fit great.

The last picture is the complete stabilizer ready for final sanding.

Next up - elevator!

FlyerInOKC

My Feedback: (6)

Looking good!

Quigleywins

Watching with intrest Yours Paul T

foodstick

I can't imagine how good this will fly, I bet it would haul a payload of what 25 pounds? It has to be alot...I think a Sig Senior will haul close to 10 if built well.

isf2008

Elevatorbuild:

I'm assembling the elevator tonight and it is going very well. Part fit is excellent. It is almost like building a plastic model - just trim the little nubs off the parts and glue them in.

One of the unique construction methods that Hobby Lobby uses is locating mating parts by a pair of holes in the parts, and sliding the parts over two nails, each imbedded in a piece of MDF. Installing the nail in the MDF causes a little ridge on the back side of the MDF around the nail. This prevents the parts from seating flush against the MDF. A little trimming with a knife fixes that problem (as shown in pic 1 below).

- The first thing I did in building the elevator was to laminate the hinge pocket ribs using the registration pins (afancy name for the chunks of MDF with the nails through them). I was skeptical that this would actually work, but as the photos show it works quite well. Place the first part on the pins and slide down to the MDF. Put a little medium CA on the second part and put it on the pins and slide down onto the first part. Same again with the last layer. Works like a charm. One small issue is that excess glue builds up on the nails. I removed it with the back side of my hobby knife.
- After the hinge pocket ribs were built I laminated the elevator leading edge together on a 4' level. I use a variety of objects to weight down assemblies while they dry. These range from machinists' 1-2-3 blocks to bags of lead shot to boxes of shotgun shells to batteries from my cordless drill.The idea is to keep the parts straight, so whateveris handy gets used.
- The elevator is assembled on a plate much like the stab. Once the leading edge was dry it was glued to the elevator plates and clamped to the level to keep it straight.
- The basswood elevator joiner plate was glued to the plate and LE.
- The ribs were added next.

I'm taking pictures of half the elevator to show detail. Note that the tail spans 52"...

That's it for tonight! Next post will finish the elevator assembly and move on to the fin and rudder.

As far as lifting capacity goes apparently the bomb bay that is included with the kit will hold 7 lbs of candy or whatever. With over 3000 sq in of wing plus the lifting stab there is lots of lifting capacity available. Target weight of 32 lbs puts the wing loading at roughly 26oz/sq ft. A cargo of 18 lbs (AUW of 50lbs) would put the wing loading at 41 oz/sq ft... This might require the use of flaps for thetakeoff run to be reasonable, but would not be out of the realm of possibility. The DLE 85 and 26x8 prop slated to go on this plane put out 50lbs of thrust at 80% power, so as long as the airframe holdsout I don't think cargo carryingcapacity is an issue.

FlyerInOKC

My Feedback: (6)

It is really amazing what you can use to weight down a glue join when you think about it. One of my favorites I have picked up on RCU is using telephone books for wing sheeting.

bonzerr1

isf2008

Elevator Build cont'd:

This post continues the elevator build...

- After the ribs, the hinge pocket ribs were added
- This was followed by a piece of trailing edge stock, one per side
- Tips were cut from 1" triangle stock and added to the assembly
- Filler blocks were then added to the inboard edges of the elevators, and the trailing edge stock trimmed to match the angle of the rudder clearance area
- I also added a filler strip on the elevator joiner plate to provide a surface for the covering to attach to. I'm anticipating that most of this filler strip will get sanded away, but better safe than sorry.

Fin to follow shortly!

isf2008

Fin build:

This post covers the construction of the fin. Like the hinge pockets on the elevator, the fin is laminated from three layers of balsa using the registration pins for alignment.

A note on adhesives:
Being a bit of an old-timer and perhaps a purist, I favour carpenter's glue such as Titebond for most assembly work. While it has very strong initial tack, there is time to reposition the parts should an error in assembly be noted. Carpenter's glue cleans up with water and sands easily, so it isa natural choice for gluing sheeting and any parts that will be sanded. It also fills gaps. However, because carpenter's glue is water based, it will warp thin parts, and is not suitable for joints with large surface areas as it cannot dry properly. While most of the stab and elevator were built with Titebond, all part laminations were done with medium CA.

Fin construction starts by using the registration pins to create four different parts from 3 layers of balsa.
- V1 and V2 were built first to get confidence in laminating larger parts and they are the smallest of the fin pieces.
- The leading edge, V4, is straight-forward to assemble - I had to be careful to that the parts were aligned in the middle of the assembly before pressing the parts together.
- V3 is the trailing edge of the fin and contains the hinge pockets. Again, this is easy to assemble.
- A little trimming and sanding results in 4 assemblies that fit tightly togetherand comprise the perimeter of the fin.
- Two laser-cut braces, V5 and V6,completethe assembly.
-After lamination, the finwasassembledwith Titebond and set aside to dry.
- Even though it was not called out in the instructions, I laminated the dorsal fin as well.

The entire construction of the fin took less than half an hour.

Next up - the rudder!

isf2008

Building the rudder:

The rudder is made up of several sheet parts laminated to a plywood core, with ribs added to that and sheeting over the whole thing. When I first read the instructions on how to build the rudder it seemed intimidating, but once I got into it everything made sense. Once all the parts are located, construction begins. Given the thin sheets involved I used CA for the entire rudder. The rudder is built one side at a time.

- 1/16" balsa sheets are laminated to a 1/16" ply core using the registration pins.
- More laminations are added, again using the pins.
- A laser-cut leading edge slots into the plywood core
- Ribs are then added to the structure along with the hinge pocket covers.
- The area at the base of the rudder has to be sanded so the rudder skin fits properly.
- Using the registration pins, the rudder skin is added to the assembly.
- The second side of the rudder is build just like the first side up to the point where the rudder skin is added.
- Because the completed side of the rudder is curved, you can't use the registration pins. Two pieces of 1/8" dowel are used instead. Once the dowels are inserted in the rudder assembly, adding the skin is a cinch. The result is a strong and warp-resistant part.
- After assembly the leading edge is removed in way of the slot for the elevator.

Like the fin, construction went quickly. I built the rudder in maybe half an hour. Part fit was excellent.

The next post shows the completed empennage...

isf2008

Completed empennage:

The tail group, which includes the stab, elevator, fin, rudder, tail wheel and servos is removable as a whole from the fuselage to make transportation easy. The attached pictures show the tail group assembled with the hinges. The hinges fit perfectly in the hinge pockets. With the tail group assembled you start to get a sense of how big this airplane is going to be. I like to do all my sanding at once, so the empennage is going to be put aside for a bit while we move on the fuselage.

Next up - building the fuselage sides!

FlyerInOKC

My Feedback: (6)

Great looking build so far. I love the quality of the kit!

erie_flyer

These large R/C airplanes are incredible to fly. I had a 1/3 Sig SpaceWalker in the 1990s at the old Milton club. Powered by Zenoah 38.

Landings were incredible. Line up to the runway, slowly reduce throttle and the big kit flared itself onto the ground. Just had to stand there and watch.

Should be an awesome sight on the sod farm.

Bill 13893

isf2008

My apologies for not posting over the last few days - been a very hectic work schedule. Plus, I had to get a few things off the honeydo list... Anyway - I've been working on the fuselage over the last few days and am going to start with building the fuse sides.

Fuselage Build:

- The fuse is built out of laminated balsa parts. The main front section is made up of two layers, each with three parts. Each layer is glued together separately (see the first four photos). The inner layer has all the locating notches for the firewall, formers and tank floor with the outer layer just being plain. You can see from the photos that theinner and outer plies run cross-grain to each other. I used thick CAto join the parts.
- Once theinner and outer plies are made, a quick sanding gets rid of any lumps and bumps, and then its time to laminate the plies together. The manual says to use gorilla glue, but after reading the cautions in the manual and the posting by bonzerr1 I decided to use structural epoxy (photo 5). While there are several products on the market I use G-2 by System Three Resins. The product mixes 2 parts resin to 1 part hardener. I use a small scale and mix by weight. This product has a long open time (45 minutes) and takes roughly 24 hours to cure.This gives the glue an opportunity to soak into the wood. The resulting bond is really strong and not brittle. The plies are located using several dowels. I also used some straight pins and a bunch of weights to hold the parts together. Photo 6 shows the fuse sides laminated together. Of particular importance is that you need to make a left and a right.

Next post will continue with the fuselage build...

isf2008

Fuselage build continued:

Now that the fuselage fronts are done we continue by finishing the side assemblies and building the sub assemblies that go inside the fuselage.

- The rear portion of the sidesis made up from laser-cut 3/8" balsa stringers. These are joined together and then joined to the fronts with 30 minute epoxy.
- While these assemblies were curing I made up the wing capture bolt assemblies. These consist ofcircles that hold a blind nut, andareepoxied into holes in the fuse sides at the front and rear of the wing. Bolts protrude out from the sides and fit into slots in the wing.
- Next is the wing anti-pivot mechanism. This assembly consists of polycarbonate plates that are fastened to a plywood base and separated by a spring. The plates slide back and forth on bolts. Tabs on the plates fit into slots on the wing and prevent it from rotating around the wing bar.Getting the clear plastic backing off the polycarbonate was a bit of a chore, but after that the parts assembled quickly and fit perfectly.
- The landing gear platemade up of3pieces of 1/8" plywas laminated using 30 minute epoxy.The parts were aligned usingdowels, which were left in the assembly and trimmed flush with the surface. The three parts are labelled A, B and C, andsuggested assembly is in that order.However,onplate Bthere aretwo holesat the rear that are for the wing strutplate blind nuts. These are not present inplates A and C, so I put plate B on top so I could drill the holes out after assembly. Hobby Lobbyneeds to update theirlaser-cutting drawings toinclude these two holes inplates A and C.

There aresome additional parts that need to be added to thefuselage sides and this will be detailed in the next post.

pogoed

GREAT build thread Andrew, I can't wait to see her fly! The link to this thread needs to be an addendum to the kit's supplied manual.
Tom

isf2008

Fuselage Build cont'd:

We interrupt this fuselage build to bring you a news bulletin!

The mail man stopped by the other day and brought me a brand new DLE85 for this project! While the DLE55 would probably be enough power for the Telemaster I can't resist the urge to put a bigger engine on it. I have attached some pictures of the engine, as well as some side-by-side shots with a DLE55. While not apparent in the pictures the 85 is a fair bit bigger and heftier than the 55. According to my scale the DLE85 weighs 26oz more than the DLE55. Witha bigger prop and some firewall reinforcements I estimate that the DLE85 setup will weigh about 30 oz more than the DLE55 setup. In choosinga powerplant for the plane I reviewed four possibilities:

DLE55
DLE85
Rotomotor 85 (four stroke)
Rimfire 65cc Electric

I compared the weights of the power systems (including motor, prop, spinner, ignition, muffler, full fuel tank andthrottle servo / speed control and battery as applicable) along with power and propeller tip speeds. It goes without saying that the DLE55 is the lightest powerplant. The DLE85 was next in weight, and makes the most power. TheRotomotor,while a sweet engine,came up about42oz heavier than the DLE55, and makes about the same power as the 55 (though in a completely different way). What surprised me was that the electric setup was the heaviest, being 66 oz heavier than the DLE55.This is due to theweight of the batteries (12s 10,000mAh) and the fact that the Rimfire 65cccomes in at 52 oz on its own. Also,the electric setup gave much shorter flight timesthan the gas setups (10-15 minutes vs 20-30 minutes or more). WhileI really like the Rotomotorthe geometry of the engine really doesn't lend itself to the Telemaster fuselage. I'd have to alter the frontof the fuse quite a bit toget it to work.Cost was also a factor. Givenall this along with the good reviews of the DLE85and the lower costI'm going to give it a shot.

Nowthatthere is now going tobe more weight up front compared to the 55I'm going to need to be conscious ofwhere the radio, batteriesand other components go in the fuselagein relation to the center of gravity in order to reduce or eliminate the need for ballast.This will be reflected in future build notes.

One final note on theengine choice: Yes, I know it's overkill. Iknow the plane will be overpowered and that the 55 is probably the mostrational choice. Propped correctly the 85 will not generate excessive airspeed so I'm not worried about pulling the wings off. I also know that the DLE85 is maybe not everyone's choice in an 85cc engine, and I respectthat.It's still going on this plane.

After somecalculations here are someestimated flight characteristics:

Prop - 26 x 8 Biela carbon
Maximum speed: 51mph
Cruise speed: 41 mph
Max thrust: ~50+ lbs
Thrust at cruise: ~34lbs
All-upweight:32lbs
Wing loading: 24oz/ sq ft
Stall speed: 25 mph
Stall with flaps: 16-17 mph

Basically the Telemaster will be a slow-flying floater with unlimited vertical capability and great towing/load carrying ability.

Now,back to the fuselage build!

isf2008

Fuselage Build cont'd:

This post will cover building the firewall and finishing off the fuselage sides.

- The firewall is laminated from 3 pieces of 1/8" ply. The carb on the DLE85 is very close to the firewall when the engine is mounted. Using a hole saw I cut out a disk from the first firewall piece to give a little more room around the carb. The firewall is assembled using dowel pins and 24 hour epoxy.
- On my gas powered planes I like to use the Du-Bro fueler so I don't have to unhook the fuel line from the carb all the time. These fuelers are mounted on the side of the fuse. The problem is they can only accommodate 1/8" thick material, and the fuse sides are 3/8" thick. To solve this I made a fueler mount from the disk I saved from the firewall. Using a forstner bit I removed just enough material to seat the disk in the fuselage side. A hole saw was used to remove the remainder of the material where the disk seats, leaving a gluing edge. After drilling the disk to fit the fueler I glued it into the fuse. This feature could easily be built into the kit by laser-cutting some holes in the fuse sides and providing a disk and spacer from plywood.
- Next up is installing the wing bar brace plates. These are plywood plates that provide a bearing surface for the wing joiner bar. On the left side of the fuse a single plate is installed on the inside. Dowels are used to ensure the correct location. I glued this plate in with 24 hour epoxy.
- The right-hand wing bar brace plate is actually an assembly that uses a piece of bent music wire as a stopper to hold the wing bar in place. While the instruction manual tells you to laminate the three pieces over the registration pins I chose to laminate them right over the fuselage using the dowel pins. Again 24 hour epoxy was used for this step.

Now that the fuselage sides are completed it's time to join them together!

isf2008

Fuselage Build Cont'd:

The next step is test-fitting the firewall, tank floor, hatch plate, formers F2 and F3 and the wing latch plate into the fuselage. The pictures in this post show this.

- Given the heavier engine, components such as the fuel tank and radioneed to be located more towards the rear of the aircraft. I also didn't want to add any additional weight forward of the CG, so the tank will be mounted directly to the tank floor, with the rear end sticking through former F2.

- The ignition and optical cutoff switch will be located behind the firewall, as rearward as the length of the hi-tension lead will allow.

-The throttle servo will also be located behind the firewall in the most rearward position.

- There are no explicit directions for mounting the radio equipment, which I think is unfortunate. On an aircraft this size I think using a power expander is mandatory. I have used the Smart-Fly SuperReg on my Big Stick 85 with a great deal of success, so will be using one on the 12' Telemaster.I use two 2S 2200mAh LIPOs to power the radio. They are light and last quite a few flights. The most obvious location for all this radio gear is under the supplied top hatch, which runs from the wing latch plate to the wing bar, or basically in the center of the wing chord. This is right on the CG. I wanted to move theradio and batteries behind the CG to balance the engine, so the next obvious spot is between the latch plate and former F3. Unfortunately the hatch doesn't run this far back, so the only option is to extend the hatch back to F3. This has the added benefit of providing access to the latch plate mechanism, which would normally be covered by sheeting. Rummaging through the extra wood from the kitrevealed two 10" lengths of 1/8" x 1/2" basswood from the stabilizer spars, which are perfect for extending the hatch rails. The supplied top hatch magnet plate and handle will be modified to workwith the new, larger hatch. Hey Hobby Lobby - thismodcould easily be added to the kit and would provide alot more access to the area inside.

-Looking at the bottom of theaircraftthebomb bay assembly screws into the large opening behind the landing gear plate. My photo actually shows thebomb bay platebackwards in the fuse,but you get the idea. The bomb bay itself is quite deep, and extends up into the fuse almost to the bottom of the wing. This interferes with the proposed radio mounting rails, so I'll have to trim the bomb bay sides and end plates down by 1/2" to clear the rails. Shouldn't really impact the function of the bomb bay, and will save a teeny bit of weight.

Now it's time to take all this apart and prepare the parts for permanent assembly!