I'm starting a plan for an all-around beater that can fly 3D with a two-stroke .60. I've been looking around at some of the available stuff (it's all arf's?) to get a feel for what area and weight I would need to meet, but everything that claims to be .60 size actually is .90 size. Any advice? Seems like a .46 sized airframe would just be the tiniest bit too small and the .90 would be quite a bit too large. Has anybody had success with a regular ol' OS .60FX?

Hangar 9 is going to offer a 60 size TWIST...
Should be out VERY SOON...

The 40 size flyes GREAT with an OS 46ax so maybe
the 60 will fly with a 60

Go to Swanyshouse.com look for Mojo 60. You will be assimilated, resistance is futile
Good to see you here, 1/2A Master.
Saludos.

ptulmer,
Funny you should mention that, I've got a 60 size original design profile on the boards right now! I agree, the 60 sized motor seems to be an orphan engine these days. I think the 3D numbers game has done that, needing the right power to weight ratio with a light enough wing loading. My ship will have, I can't remember exactly but its in my design book, around 880 sq in of wing area. Span is going to be 42". I like to keep the span short and the chord large to keep the center of lift close to the fuselage. That helps keep wing rock out of harriers. My numbers aren't far off from what is found in many "40" sized machines. What I will do is play around with moments to get the right CG without needint weight in the tail. That's one of the nice things about scratch building. Best of luck with your project. Don't cave. Stay with it and build your own!

Dave

Bolio! Thanks for the link. I should have remembered to look at his site.

AeroDave, what weight are you shooting for? Looking at Tower they say the GMS .61 will turn an 11x7 @ 13k. That's realistic enough to work from, so inputing those specs into ThrustHP (flawed, but workable) shows a realistic 1.6hp and 7.42lbs static. Using that hp rating, but changing props to a 13x4 shows a rather hopeful 13.39lbs static. These numbers sound like a 5-5.5lb airplane might 3D pretty well. How realistic do you think those numbers are?

I probably should add the fact that it's going to have a pipe tunnel, so that is a power option.

I think a 5 lb plane is a very reasonable goal. It sounds like you're not new to this, so just like always select your wood and don't over build. If mine weighs over 5 I'm gonna be ticked

oh yeah.... I'm going for 4.5 lbs. As far as your static thrust numbers i really don't know.....
Honestly if I get ten out of my OS 61 I'll be happy. I had it in a 5.5 lb Goldberg Extreme 330 and it pulled out of hover strongly, but wasn't a rocket.

AeroDave, if you want to learn how to keep the fat out of an airplane, you've got two choices. 3D or 1/2A. I took the latter route. www.ulmer-rc.com

Here's a very, very early design picture:

I've had good luck flying my Kangke Fun 50 with an OS 65LA. Lots of fun for the dollar investment. Standard servos and receiver and an OS 65LA make this plane fly well.

Here's one I just finished about a week ago. Its got a .46 on it. My .61 will be much like it except I will use a longer relative tail moment .

Here's the start if the .61 wing.

Very nice! That brings up a question. What do you think of ailerons that are made from part of the airfoil like the Funtana? Better, worse or equal? I want mine to be able to make those nice, quick passes down the runway, so flat ailerons are out and strips are too small.

Better. just make sure they have double bevels for 3D throw As I'm sure you know, but just for other folks who might read this, the size of the control surfaces usually used for 3D limits usable top speed without flutter.

Flutter is definitely the enemy. I was thinking about the GP RV-4 kit having that style of ailerons, too. I think with a pretty firm setup, like servos in each wing, might be ok. BTW, that was a very nice way to remind me.[&:] Don't worry about my feelings though. If I knew it all, I wouldn't be here asking questions. Just don't anybody tell my wife!!!
I'm going to ask alot from this airframe, but I want it to work the first time!


BTW, I think it's about time to hop downstairs and build a 1/2a PBF. It takes about two hours...

Yeah, those planes on your website look pretty good! be sure and post lots of pics as you get your design going. Hopefully, we can get good design descussion going here.
Take care,
Dave