Trike gear on flying wing stunter.

Stuka Stunt Main Forum · 4 of 4 known posts recovered

Jim T. · Mar 15, 2001 07:51 PM

I'm redesigning my Agile Arrow flying wing from a taildragger(so to speak)to a trike gear. Should the airplane sit level on the gear, or should the two rear gears be a hair longer or shorter than the front gear? Also, how far behind the CG would you mount the rear wheels? Say the front wheel center is roughly 6 in. ahead of the CG (Plans are out in the workshop). Should the front gear be furthur forward or back? The airplane is 25 in. from the back of the spinner to the hinge-line of the elevator. The CG is about 9 in. back of the spinner backplate.

Thanks, Jim

The Kiwi · Mar 15, 2001 09:45 PM

#1 source

LAST EDITED ON Mar-15-01 AT 09:46 PM (EST)

The same rule of thumb that works for forward mains works when it is a rearward set. The point of contact for pavement is 15 degrees "behind" the CG point. The nose gear location is mainly a matter of somewhere you can mount it securely. Whatever you do, don't make the nose gear shorter than the main gear or all you end up with is a taxiing demon (go ahead, ask me how I know!)

Of several I've flown with trike gear, those that sat totally level at rest were easiest to handle for takeoffs and landings.

The K.

._.

Steve Helmick · Mar 18, 2001 04:42 PM

#2 source

I'm really mystefied by Kiwi's nose down "tether car" account. This shouldn't happen unless the rear/main gear is too far aft, and on a trike, that's going to be quite a distance. Have heard of conventional models with 2 wheel LG doing this with too long a tail wheel strut, because the model couldn't "rotate". I have flown two trike ukies, and they were ok except that if the nose sat high, the nosegear would hit first and it would bounce like mad. Flat might work ok, but there shouldn't be a problem with a nose low setup. The mains should be about 1" behind the CG, so that when you touch down, the nosegear isn't slammed down. The 15 deg. should work, but might be a maximum. Closer to the CG will also minimize the forward tipover that killed off the Honda "trikes". There were dozens of classic stunt designs published with trike gear, and they should give up some ideas for your model. Steve

John Miller · Mar 18, 2001 05:37 PM

#3 source

Ok, here's the real scoop on trike gear.

First, they can be very desirable if set up correctly because it's almost impossible to mess up a take off or landing.

Set the plane level when it's on the gear. A degree of down or 3 won't hurt if the gear is set up right. Avoid too much nose high stance on the gear as the plane will jump off when it's ready to fly, not when you want it to rotate.

The mains are the key to good take offs and landings. I set mine up so that when the tank is empty, and I push the tail down it will stay down. This is about 1/2 to 3/4" behind the CG. The further behind the Cg, the more elevator pressure needed to rotate the plane for take off.

Set up correctly, the plane should stick to the ground on takeoff until you want it to rotate. the amount of elevator needed to rotate should be no more than thinking about it for it to lift off ever so slightly and smoothly. Again if the mains are too far behind the CG, you will have a larger ampount of elevator deployed to get it to rotate and then it will jump into the air. There goes a whole bunch of points.

When the plane comes in for a landing with the gear set up this way, you can land smoothly with the nose high and roll out on the mains with practise. It's fun to do that and then drop the nose gear right in front of the judges for additional impression bonuses. In windy weather, you can land on the mains going down wind, plant the nose gear going cross wind, and give down elevator to hold it on the ground gong up wind.

I've seen pilots pick up 15 to 20 points in their pattern by useing and learning the ins and outs of trike gear.

For a flying wing, I would mount the mains about 1/2" behind the CG, and the nose gear as far forward as possible. Set the plane level on the gear. This should work fine and allow some great takeoffs and landings.