Navy18

My Feedback: (4)

I was wondering about the specs for the Great Planes RV4........ the numbers look like a 60 size plane. What do you builders who have experience with this model think about a 60 2stroke as a powerplant for this model? Could some reinforcement do the job? Possibly add a rib on both wings to add wing area? What are your thoughts on the model? Thanks.

cruzmissile

well, I had... notice I said "had"... a GP RV-4 once upon a time. It was a great plane to build and fly. I had an O.S. .50SX in the nose and it handled really well. As far as specs go, I don't really have any off hand, a .60 engine might be a bit much for the little plane. It lands real gently and I installed the flaps for it, however, it slowed down really really slow when applied, so be careful with the angle of flap deflection if you op to build it with flaps. It doesn't really need flaps, but it looks really good with them. Anyways, that's all I have to say about that, I'm sure someone else out there will have something else to say about this kit. Have fun with it and enjoy.

barto

.60 will be more than enough power, but if you want that much go for it. Just consider the weight, this bird is pretty heavy build(you won't need any reinforcements) so you might add a rib on each side of the wing to get some more wing surface. You don't need the flaps, I didn't use them and she slows down pretty fast. Make sure you build the tailfeathers with decent balsa. My stab broke after about 20 flights, luckily it landed ok. The monokote held it together

Navy18

My Feedback: (4)

Thanks for the info ... I am getting the feeling the OS61fx will be max overkill. Thinking of finding another project for it; I am curious, how did the RV4's handle? Were they fun to fly?

barto

Well, its not a very aerobatic plane, it is very agile but not good for IMAC.
It loves to turn very short, low passes are nice, I cant do any KE with mine, rolls were not axial in the beginning, but when I moved the CG back it was much better, still not very axial but I think thats normal.
What flying style do you like? For regular sunday flying the RV is good, if you want to practice IMAC or 3D, you need something else.
BTW, that 60 will be pretty doable, just lose some weight while building, this bird is pretty overbuild.

Hope this helps

Bax

My Feedback: (11)

Here are the engine specs for the Great Planes RV-4:

.40-.52 (6.5-8.5cc) (2-stroke)
.48-.70 (8.0-11.5cc)(4-stroke)

And the Website:

http://www.greatplanes.com/airplanes/gpma0180.html

ksechler

Man Barto, I don't know where you're coming from. The RV-4 is plenty aerobatic and rolls are as axial as they get. Maybe yours has a warp or trim problem. Mine flies like it's on a rail. I agree that this isn't a 3D plane, though.

Mine has a .46 FX and the flaps. It's too heavy for unlimited vertical, but will draw a pretty good upward line. Adding the .61 would work fine. The airframe is sufficiently strong, and that would give you an unlimited vertical. Don't waste time adding to the wing. You don't need it. Just put the flaps on so you can slow it down for landing.

Another alternative would be a strong 50. I am considering swapping my .46 FX for an Enya .50 CX (I already own).

dr_wogz

My Feedback: (3)

The narrow cowl also present a few 'fit' problems. that is, up and down; plenty of room for the cylinder head (side to side room) but none for the muffler, pitts or not..

My buddy's had an MDS .48 with a pitts style muffler. The muffler eventually chewed a hole in the bottom of the cowl, from heat and vibration. It was only one corner, but enough to 'be ugly'

A low 50 sized engine would be about the max for the plane.

If nothering else, an extra 'dehedral joiner' in the wing would be a good mod, as the two supplied offer.. jsut enough support. His, from a 'lull', dropped form about 8 feet. Minimal fuse damage, but the wing split in half.

(and GP don't offer wing kits....)

barto

ksechler, whats you setup?
I mean, what throws do you get on your ailerons, where did you put your CG?
Also, I think I have a problem with the aileron differential I have dialed in. When I turn left (ailerons) should the right aileron go less down then the left aileron goes up or is it the other way around? How much diff do you need? Will increasing the diff affect roll rate??

BCJETJOCK

Put a .70 4-stroke on it. And you'll have all the power you want, and manuvers galore.

privatepilot

My Feedback: (1)

I put an .80 4 stroke on mine and it will basically go straight up out of site. WAY to much power for the plane. Mine has flaps. Can't imagine landing it without them with a 12 or 13 inch prop. =) Anyone lookin for a hardly used .80 4 stroke? [8D]