P47 Jug - Al

My Feedback: (1)

Hi,

[link]http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXBMM9&P=ML[/link]

I am setting up a GP’s Big Stik 40 with a super tiger 45. GP’s suggests placing the engine towards the front end of the engine mount. However with the Super Tiger, the plane is very nose heavy. If I move the engine back (I could easily move the engine back an inch or a little more) to help the CG, will I disturb the aerodynamics of the plane in a negative way? The only other option is to add weight to the tail. How much, I am not sure. But if I can play with the engine position, that would save weight in the tail.

Any ideas?

Thanks
Al

redfox435cat

thats the best way to balace it. it isn't going to affect the model in any noticable way. Just do it. Also you can get an extension and put the battery toward the tail.

P47 Jug - Al

My Feedback: (1)

Thanks for your feedback!

Jstanzak

I have a GP Bigstick 40 with the engine shoved all the way back in the mount without a problem. But then again I am running a hundertiger pro61.

Ed_Moorman

My Feedback: (1)

I have a Big Stick 40 that I use to break in mid-sized engines. It does come out nose heavy. If the plane doesn't have a cowl, I normally put the engine as far back as it can go unless I know before hand that it builds tail heavy. In my case it has had 2 GMS .47s, 2 OS .46AXs, a Saito .56, Magnum .70 4-stroke and an OS .50. It flew well with all of these engines.

In the case of the Big Stick 40, I also moved the rudder servo to the rear. It might better with both the elevator and rudder servos in the rear.

If you are planning to do knife edge, you want to at least turn the dihedral brace over for some anhedral. It really needs more than this. The usual figure is 3 degrees on each side. Pretend it's a low wing plane flying inverted. The white/tan strip in the center of the wing is balsa gap filler from adding the anhedral.

top242

Hi!, for more aerobatics ist better 0º dihedral? i am an expert pilot. And.... the landing gear, ist better bicycle? . The engine, os46ax , asp524T , or os 50sx? Thanzs!

Joseph Ryan

I have just finished balancing my Big Stik with a Super Tiger .61 on the front, it required 7.25 oz at the very rear in front and under the vertical stabilizer(inside the fuse). In addition I moved the battery pack behind the servo tray. I also put 1/2 oz weight at the outer left wing (opposite the engine muffler) for lateral balance. It is now completely balanced I can't wait to fly it.

P47 Jug - Al

My Feedback: (1)

A Super Tirgre 61, WOW, that thing will tear Let us know how it flys! I have a ST 45 and it flys well with it. I also added a couple of ounces on the tail too. Have fun!

Al

Ed_Moorman

My Feedback: (1)

Top242: 0 degrees is better than dihedral on a high wing plane, but it really needs anhedral. A high wing location on the fuselage is the equivalent of 3 degrees of dihedral so you need 3 dgerees of anhedral to get back to neutral. If you stay with 0 degrees, the plane will roll with rudder in point rolls and knife edge. If the wing is already built, you can add downward end plates about 3/4" below the wing. These act like anhedral and will also compensate for the high wing location.

Take any low wing plane with dihedral and turn it over and what do you have? A high wing plane with anhedral. This is what you are looking for.

By the way, if you build a low wing plane with 0 degrees dihedral, it will roll opposite to the rudder and want to roll over on its back in knife edge. That's the reason low wing RC planes have dihedral, not for stability. We want neutral or 0 roll stability for acro planes so we don't have to counter control for the stabilizing effect. The plane should stay where we put it, not roll out.

Joseph Ryan: A heavy engine is the reason I have the rudder and elevator servos in the tail of my Ultra Stick and the battery behind the wing. I hate to add lead-it just increases the wing loading and decreases performance.

Joseph Ryan

Thanks Ed I agree with you about the lead weight being nothing but parasitic load, I wish I had visited here before I built it, I probably would have done what you did. Why did you add the wire to the tail?

Ed_Moorman

My Feedback: (1)

One of the other guys bumped his tail and cracked it loose. It isn't in a slot, only surface glued to the fuselage sides. I added the bracing wires just in case. I normally use something lighter, like weedeater line, but since a little more tail weight wouldn't hurt, I went with heavier wire.