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Sep 27, 2005, 08:14 AM
Crash Master
Gene Bond's Avatar
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Yak54 30" EPP sheet 3D 'Trainer'

Here's the latest one I have been working on. I used EPP sheets from for the basis of the design. I've been through a ton of BluCor and Depron on my 3D training!

I was replacing my original 24" Mini 3D, which I turned over to a buddy for his abuse/education. I wanted something a little slower and gentler.

It's pretty honest. It has a little rudder-roll coupling, but not bad. I could probably program it out, but instead, I just fly it.

It'll do all the basics.

It's a hair too heavy for a single CDR motor and 2s packs, but is fine on 3s.


270 sqin
70 watts
4 oz/sqft
150 w/lb

Here's a couple of possible power choices:
2s830-1320: Komodo KH-278, 12t/24g, 9x3.8-10x4.7
3s340-830: GoBrushless (or Len's, StrongRCmotors, etc) Single, 19-20t/26g, 8x4

Of course, it could be built from FanFold or Depron. Just check your bracing. I used 2 of the 3mm ultra-light tubes from BP or Slofly: It's just strong enough for this application... I get some wing flex and some tail flex.

I used a 24" tube in the wing, and a full length tube in the fuse. I sank both with a soldering iron on a straight-edge, and hot-glued into place.

I decided to try the Robarts hinge points on this build. I like them, even though they are somewhat expensive (~$3.50 for 15 pieces). I used 3 per surface, so 12 pieces. The way I mounted them was like this: I wrapped a paper clip around the tip of my soldering iron, extending the tip out about 3/4". I used this to 'drill' a hole into the edge of the wing/stab and the beveled LE of the control surface. I then pumped hot-glue into the hole, and shoved the hinge pin in until the joint was just flush. I bent the hinge at 90 so I could assure proper orientation as the glue cooled. Then I did the same on the control surface, doing all 3 at once. It worked well, and they hold up better IMO than tape for the EPP.

I set mine up with dual aileron servos, so I could play with flapperon mixing with elevator... I like it!

Anyway, here's the plans, some pictures and video... Enjoy!

Edit: By request, I scaled it up to 36". Also changed the marking scheme, if you want to use it for masks...
Last edited by Gene Bond; Jan 04, 2006 at 08:25 AM.
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Sep 27, 2005, 11:32 AM
Registered User
jerbear's Avatar
Nice flyin Gene ........... great camera man too !!!!!!

Sep 27, 2005, 01:16 PM
Dave North
timocharis's Avatar
If I had grass that thick to fly over, I'd color the plane green and crash it just for fun! I guess you have to clean stickers off and stuff like that...

Looks good!

Sep 27, 2005, 01:29 PM
Crash Master
Gene Bond's Avatar
Thread OP
Yea, in one part of the video, you can see me picking grass out of the prop

And, very little of that is grass... It's clover, mostly. Hay field. It's a little bit of paradise behind Jerbear's place
Sep 27, 2005, 08:25 PM
Registered User
ewo's Avatar
that looks great Gene!
and great flying man, its on my list to build, as soon as i get over my not feeling so good

Tell the camera man he did a fine Job!!

Sep 27, 2005, 10:48 PM
Crash Master
Gene Bond's Avatar
Thread OP
Originally Posted by ewo
Tell the camera man he did a fine Job!!
He told us!

great camera man too !!!!!!
Sep 30, 2005, 04:28 AM
Ok here comes the questions
Looking at the pic.s It looks like you are useing the epp at 9mm thick?
I asume that the c/g is at 1/3 cord. please correct me if I am worng.
Thanks Scott
Sep 30, 2005, 06:11 AM
Crash Master
Gene Bond's Avatar
Thread OP
Yes, the EPP is quite thick. 9mm sounds about right.

CG is 35-40%

I'm thinking I want a little more rudder area... It works fine, but I find I have to give it a little more throttle than I'd like to tuck the tail under properly, when entering hover from knife-edge. I think I'm going to scab on about 1/2" additional chord to the rudder and see if it acts a little better. This is just a personal preference.

BTW, I highly suggest the E-Flite S75 servos. They are awesome with the long arms and long leads. They seem very strong, and I've had no problems despite all my efforts. I just wish there were some great, strong, high-throw 4 gram servos out there for $8 apiece
Sep 30, 2005, 07:34 AM
*sniffle* I miss Indiana... Great vid and great plane. Now if I only knew how to scratch build
Sep 30, 2005, 07:39 AM
Crash Master
Gene Bond's Avatar
Thread OP
Just do it! Pick something simple like a Bird Dog or BluCub, and get one under your belt... Catch the Blu Flu

My first 3D'r was BluCor, and lasted about 3 seconds before it got its first repair. It finally got too heavy and had to be recycled. Since then, I've built them from BluCor, Depron and EPP. I highly suggest EPP for 3D training. Sure you can tear the foam, but it takes some effort!
Sep 30, 2005, 07:52 AM
Oh Gene, I most meant trying to get the plans printed. Im not sure how to go about it.
What program are you using to create the drawings and make sure it has the correct wing shape, area etc..
What type of cutter do you use? I have looked at several. Some bow styles on ebay for like 38.00 that just require a 12v battery charger.
Sep 30, 2005, 08:39 AM
Crash Master
Gene Bond's Avatar
Thread OP
I use TurboCad to draw, and Adobe Acrobat for formatting to tiled pages. They should print fine from the Adobe reader:

As far as shapes and areas, most of it is hit-and-miss with a little experience and gut feeling thrown in. I've only been at flying for about 5 years, but boy have I learned a lot! Mostly, here, btw

I don't use a hot wire cutter very much. Most of the stuff is cut with a regular old #11 blade (Xacto) which I sharpen on a hard stone every time I pick it up. The old blade that's in there is over 2 years old, and is getting short! I can barely get through 2 layers of FFF any more.

The EPP sheet I got from Steve at He's working on making some thinner stuff, too, so we can do built-up structures...
Sep 30, 2005, 09:27 AM
Well I printed the tile version. Didnt quite come out to 30" more like 29.5, I probably have a setting that needs changed.
Sep 30, 2005, 09:57 AM
Registered User
hotled, make sure you don't have "fit to page" turned on in printer settings.

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