J.Paul Saure

Hello there!

I just built a Greatplanes RV-4, this is my first electric plane after more than ten years on glow.

I'm using a Sagami 280BB, 5:1 BB MPJet gear and APC10x4.7SF. With a 9.6V 650mah Nimh it has 10 minutes of part-throttle power and it spins the APC at 4750RPM.

The pane flyes slowly very well at 1/4-1/3 throttle and at full power it has a nice steady climb. However, I can't get a decent loop or stall turn from level flight.

The airframe is very stable and precise, rolls well, has a good rudder and glides smoothly. Because of this, I think with a "little" more power it would perform solid scale-like aerobatics. (that is loops, point rolls, cuban8, split-s, immelmans, stall turns, etc for you "3D-only" flyers out there!) If I get good feedback on the power systems forum I'll get a MPJet 28/7-35D outrunner.

The picture is at a site "just discovered" less than a mile from where I live. Our club has a nice tarmac strip, short grass but lots of wind!!!!

It took me 1-1/2 months from box to air.

The build is good, nice fit of the pieces but there are some details not mentioned on the manual, for example: the rear elevator joiner needs some room to fit well.

I used two servos on the wing, much more precise than the stock linkage. I also used dubro mini ez-link on the four servos.

I used less dihedral than recommended, something like 2/3 of it.

Wood is so-so, some sheets were ligth, some heavy. I haven't weighted it but it feels very light, can't imagine how light it'd be with premium wood and lipos!!! The gear is very soft, I'll try some stronger rubber bands or hard mounting it.

I covered it with Coverite microlite, very good material, even easier to use than monokote. 3M Blenderm tape hinge, and ply horns. I used the throws and CG from the manual. The throws are perfect, the CG is a little conservative, I'll try backing it 1/8" next time. I did use a little washout as the manual suggested, the turns can be very tight and the plane still tracks well. With powered stalls the wings don't even seem to rock, the nose goes down smoothly. 7 out of 10 for the building, 9 of 10 for the flying, and I think it'll get 10 of 10 with a brushless set up!

Rounding up, a very nice parkflyer. Easy to fly and buid if you know how to. I wouldn't use it as a trainer and if building for the first time I'd recomend a little advice and supervision from some experienced fellow flyer to make sure you don't mess it up!!!

Regards,
Paul

Charley

My Feedback: (2)

Nice work, glad it flies well. Why did you use two servos in the wing? Isn't that something of a weight penalty?

Cheers,

CR

voodoo51

I am building a great planes combat p51 Its great! and cheap 95.00 4 the plane I am going to run a AXI out runner and jr servos.

J.Paul Saure

I'm sure the plane would fly with one servo, but I don't like the "torque rod" linkage.
The plane flyes very well, it is light and slow enough for me! Besides, the aileron response and feel is great with the two direct servos.

Saludos,
Paul