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Mar 10, 2014, 12:35 PM
Thread OP
Build Log

Flyguy62 Version 3: Fully Aerobatic

New video of Elvis, Flyguy Version 3.

RC Flying Elvis Flyguy Version 3 by Otto Dieffenbach (1 min 36 sec)

Flyguy 62 Version 3 Fully Aerobatic with Twin Motors by Otto Dieffenbach (1 min 11 sec)

Flyguy62 Version 3 is a fully aerobatic version of Flyguy. He is a result of my desire to add yaw control and to have a neutrally stable platform for aerobatics. He is designed for an intermediate pilot and will perform inside and outside loops, knife edge and fly inverted all day. If you aren’t comfortable flying coordinated yaw to compliment roll control, you should stick with Version 2.

Flyguy62 Version 3 is a direct evolution of the original Flyguy, February 2011. When I built Hoverflyguy this January, I experimented with several design modifications and incorporated the best into Version 3. I’ve tried to keep costs to the minimum.

The main design changes include twin shoulder mounted counter rotating motors, wheels and full lower leg elevons, hinged at the knee. Unlike Version 2, the propellers are exposed, so care needs to be exercised when operating around crowds.

This is not a true build log but a description, with pictures, of how to create your own Version 3. You can scratch build Version 3 or order Depron and ply cutouts through

I’ve included a link to the Version 2 build log so you can get a feel for what building the standard Flyguy is all about. This build has about the same level of difficulty.

Here is the link to Flyguy 62 Version 2 Build Log:

Here is a link to the master Flyguy thread for general information:


Two 39 x 27 inch sheets of 6mm Depron
5mm plywood (Home Depot)
One 40 inch long inch square carbon tube (Midwest)
One 40 inch long 1/8 inch round tube (Midwest)
1/16 high grade hobby plywood
1/16 inch plywood
Foam mannequin head (Ebay)
by inch balsa strip
Dubro hinges
Two Parkzone T-28/F-4u wheels
Music wire 1/16 inch
Gorilla Glue
Foam Safe CA with accelerator
5 minute epoxy
Long cure epoxy
Zip ties
Foam mounting tape

Electronics and Power:

A Transmitter that can mix Elevator and Ailerons (Pitch and Roll) for elevons
Two Turnigy D2826/6 2200kv motors

This was my standard configuration and the motors produced 2 years ago (2013) seem to have been of better quality. I used these motors on V3 and my can and box with the 7x4 and 3S. I started having overheating issues about a year ago with the newer motor batches. I like to keep things inexpensive and reliable but in this case reliability is an issue. A more expensive but really good motor is the Cobra 2213/12 kv 2000. It runs well on the 7x4 and 3s with 40 oz of thrust at WOT.

Two 40 amp ESCs
APC 7 x 4SF prop
APC 7 x 4SFP prop (pusher)
Two 3s 2200 mah 25c batteries (Turnigy are $10)
2- Hitec HS-225MG servos
AR400/500/600 Spectrum receiver or equivalent
Two 30 cm servo extension pigtail for servo connections


Sharp knife
Razor saw
Sanding block with 150 grit paper
Flat table/work bench
Small Philips head screwdriver
Pliers and wire cutters
T-pins or equivalent
Scroll saw
Last edited by Otto Dieffenbach; Sep 13, 2015 at 10:49 AM.
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Mar 10, 2014, 01:00 PM
Thread OP

Motor Mounting

Motor mounts are built with a 5mm ply center sandwiched between 1/16 ply squares. A slot is cut in the 1/4" ply for the carbon square tube. I rough up the tube with sandpaper and use slow cure epoxy to make the mounts.

The mount should be built so the motor shafts are 18.25 inches apart. the motor set will be zero/zero to the top/arm plate.
Mar 10, 2014, 01:13 PM
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Like on Version 2, I have ply doublers on the interior of the sides at the front. They are laminated to the Depron with Gorilla Glue. They support the motor tube, chest plate cross tube and the wheel shaft. This doubler is made from 1/16" ply.

I added side 11 x 6 inch 6mm Depron doublers mid body to reduce side fractures on hard landings. I also added a top plate 4 inch wide doubler to make the top stiffer for easy handling.
Mar 10, 2014, 01:29 PM
Thread OP

Body Construction

I first glue the 1/4" carbon square tube chest cross brace into the chest plate. I locate the hole locations for the end of these tubes on the sides (ply doublers) and drill a 1/4" hole. I square up this hole for the tube with a knife.

The legs are 18" long and their parts are separated from the sides and top plate prior to building the body.

I build the body upside down on a flat table. The top plate is laid on the table and sides are glued to the top plate and chest plate. The chest plate is parallel and 6 inches from the top plate.
Mar 10, 2014, 01:38 PM
Thread OP

Head and Battery Compartment

Update 11/10/17: CG should be 6 1/4 inches from the front, body side edge. Adjust from there.

The pictures and captions help explain this step. The support is made from 1/4" (5mm) ply and ties to the body at the motor support tube and the chest cross brace tube. It is shaped to the nose contour and supports the battery mount.

Protective edging is made for the head halves from 1/16' ply and magnets are used to hold the head halves together.
Last edited by Otto Dieffenbach; Nov 10, 2017 at 12:29 PM.
Mar 10, 2014, 01:45 PM
Thread OP


Note picture captions.

1/8 inch carbon tube or rod is used for the wheel shaft. Parkzone T-28/F-4u wheels are used.

I CA washers on both sides of each wheel to keep them in place. I epoxy the shaft to the sides. Be careful (!) not to CA the shaft to the wheel.
Mar 10, 2014, 01:52 PM
Thread OP

Control Surfaces/Hinge line

The leg hinge line is 18 inches from the toe tip. The hinge line must be strong! I have found that gluing 1/4 x 1/2 inch balsa strip to the Depron for Dubro hinge seating works great. Use three hinges.
Mar 10, 2014, 01:59 PM
Thread OP

Servo and Control Horn Installation

Since we are flying with two batteries the CG requires the servos in the rear. This helps to provide a strong, short linkage between the servo and the horn. I mount the servo in the side and glue it to the side and top plate. I fabricate a horn from ply and soak the horn around the linkage holes with thin CA, then re-drill the holes.
Mar 10, 2014, 02:09 PM
Thread OP


I parallel the two batteries together to the ESCs. I plug one ESC into throttle and the other into the gear channel. I then mix rudder to both the throttle and the gear channel to provide differential thrust. Use fixed end point ESCs or have your ESCs setup on a switch so that they never go below zero or they will always be resetting the endpoint.

The legs have about 35 degrees of throw, up and down.

CG is 3 3/8 inches behind the motor support tube.
Mar 12, 2014, 09:17 PM
Retired CAD guy
birdofplay's Avatar
I am currently working on the CAD drawings for Otto's V3 Flyguy.

I should be able to provide a PDF for his approval soon.

It will be available as a CNC cutting shortly.
I estimate that it will be 5 sheets of 6mm x 39.37" x 13.5" depron
Since there are many ways to build this version I will allow the builder
to supply his own Ply and motor mounting.

I will be offering the CNC cut foam sheets plus Plywood control Horns
for $65 plus shipping.

It is not yet on my web pages so ...

If you are interested please PM me.

Hoosier Cutout Service

edit 3/13/14
Well that estimate was WRONG.
The extra width got in the way of certain material economies and I'm currently up to 6 sheets
of 39x13.5 x 6mm

Still doing checking in 3D

Last edited by birdofplay; Mar 13, 2014 at 09:41 PM.
Mar 13, 2014, 12:20 PM
Registered User
Petefoss's Avatar
Will you also share the drawings for us DIY types Bob?
Mar 13, 2014, 09:44 PM
Retired CAD guy
birdofplay's Avatar
I normaly do, Pete, but I'll wait and ask Otto 1st.

After I get some confidence with the parts.
Mar 14, 2014, 09:07 AM
Retired CAD guy
birdofplay's Avatar
Effort to date - still not approved by Otto but
dimensions are per Otto.

Wood applications not shown but Otto's build pix can be your guide.

The Pdf is for foam parts only.

Comments ?


Images removed due to changes
Last edited by birdofplay; Mar 14, 2014 at 12:12 PM.
Mar 14, 2014, 10:56 AM
Thread OP

Flyguy Version 3

Here is the side view of Version 3. I'm not great with Photoshop but you should get the idea. From Bob's drawing, rotate the top arm plate and head 4 degrees CW. Also, rotate the leg outline just below the knee 3 degrees CW. Finally, setback the motor so that it is overlapped by the side. Also, widen the motors on shaft center so they are outside the sides. The chest plate is rotated 4 degrees CW and is 6 inches from the top plate, parallel. This leaves plenty of room for the wheels. The leg separation from the body should be just below the knee.

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