Anyone try toe-out on tail dragger gear to prevent gound looping?
 

Just curious

you want a slight toe in, just like your car.

Nooooooooooooooo you don't. That's worse thing you can do. There is a great article tells model builders to use toe out.

I have heard of one pilot in here that swore by toe out. I have always set toe in. AllI know is, once my gear get tweaked and I lose a good consistent shape to my axel, I play hell getting my Fokkers off of the ground. It seems to not have to be off by much for it to make an impact.
I say set toe out on your tripe and give it a try. It is supposed to work.

Maybe I've missed out on some great secret, but isn't it impossible to have toe-in OR toe-out on a free-floating axle? And frankly, I don't know why anyone would want a fixed axle on a WWI model.

I do not have floating axels on my Fokkers. I had nothing but trouble with shocked gears on them. Once I put solid axels in them, I really have had no problems. The issues that have arisen for me aer with the wheels themselves getting sloppy and loose. I just put a bend in the middle of the axel to set my toe. Toe in has always worked, so I never moved away from that.

Please read page 3 before making comment

http://www.rcuniverse.com/forum/images/attach/pdf.gif

sorry can load pdf file, Go to wattflyer under ww1 gear topic

Speaking of slanted wheels, here's a current car fad in Japan:

http://www.youtube.com/watch?v=_r6ltUgtFWI http://www.youtube.com/watch?v=_r6ltUgtFWI

Toe in is used on cars because the tires will tend to pivot outward slightly as the car moves forward. Too much toe out will aggravate the situation and tends to make the car wander.
For an airplane, it all depends on the landing gear design and geometry. If a plane's axle allows the wheel to pivot outward under load, then adding some tow in should help keep the plane tracking straight. Probably none of this matters if your runway is grass!

A slight amount of toe-in is desirable in taildraggers, full-scale as well as models, homebuilder's opinions aside. Here's a good article courtesy of DJ Aerotech:
http://www.djaerotech.com/dj_askjd/d...taggerbee.html

Here's the modeling NASA's take:
http://www.nasascale.org/howtos/toe-in.htm

As Don Stackhouse points out, there are so many factors involved: tail area and effectiveness at low speeds, camber, moment arm from CG to mains and tailwheel/skid, vertical CG, etc., that one answer doesn't fit all aircraft.

My Stick-type aircraft do fine with zero or just a little toe-in. My Cubs do really well with at least 2 degrees toe-in. A little positive camber (wheel bottoms closer than the tops) works well for stability also.
We had a guy in the club who let his Cub gear get splayed out (toe-out) from several firm landings, it was very squirrelly as a result.

Obviously, there are many opinions. I'd suggest experimenting a little and find what works for you. I'll bet in most cases it's a little toe-in. YMMV.

Hangar 9 recommends toe-in for their Corsair 50.

Thanks eddieC

I'm stuck with paved runways and fly 38 lb plus 1/3 scale Sopwith pup and Fokker dr1. Both ground loop and my fear is they may ground loop into someone. I think landing on the mains and holding the tail up with power until plane slows down to descend on tail skid is the best way to reduce the amount of ground looping. Both planes are set up with straight 1/4 steel axle rod fixed at the center to allow for a sprung shock. Could bend the rod ends to push wheels in toe-in position but these gears are narrow may not do much and make the ground loop more aggressive when it starts.

Valleyk, I think that's a good plan.
I've never flown a WWI plane but have seen many videos, and the most success seems to be with wheel landings.

I had a taildragger ultralight, a Kolb Twinstar, and it was a very easy plane to land and take off. The gear was just slightly ahead of the CG, which at first glance would make the plane very touchy. In fact, it had a long tail moment which, when coupled with the pusher prop, gave great rudder authority.

I have a bud who flies a taildragger Kaos pattern plane. His wheel and 3-point landings are uneventful due in large part to the long tail moment.

One trick I used on free flighters (with straight axles) was to fix the wheels to
the axle so both wheels had to rotate at the same speed.

The 'axle' was actually a fixed brass tube with a piano wire axle rotating inside.

John.

WW1 planes have two problems. The high angle that a WW1 sits on the ground. Lots of change of the toe from 2 point to 3 point. Wihen the Tail comes down, it can induce steering as the relative toe to the ground changes. Also when the tail comes down, the rudder, as most are small, gets blanked out giving no directional control. Both cases happens when the tail comes down. Getting the plane stopped fast is the best thing to stop ground looping.

That is why I find thaat getting it as slow as you can before touchdown is important. Of course this is tricky. You must understand your plane and it's stall. If it has little forward enrgy, then it will not roll as far and be less likely to ground loop.

I have never had the luxury to fly my Fokkers from grass. I have scored a perfect 10 on a landing score with my Fokker DVII at a scale masters qualifier though, on pavement, so it is possible. Set up is key.

Toe out does a couple of things. First it helps to level the plane out when one wheel touches the ground before the other. The slight toe out will not cause the plane to start to trip over its wheel instead it allows for some side slip angle and then aids in leveling the wing on its gear. On take off you may notice using a little more rudder input depending on the model.
With toe in if you have a less than perfect touch down the first tire to touch will steer the plane to the opposite direction of the wing bank angle. This will start to allow the high CG of the plane over the gear to gain momentum and lead to bouncing off each wing tip or wheel or cart wheeling.
Another example is from buggy and truck racing off road. When a vehicle lands from a jump with one front wheel touching first the angle of the wheel will determine if the awkward landing can be recoverable. Racers use toe out in part for this reason. As the one tire touches and gains traction the toe out angle levels the chassis and usually saves an otherwise poor landing.

Both toe out and toe in will induce drag as the plane accelerates or lands because the tires are scrubbing, not running parallel. The amount of toe out were talking about is no more than 3deg out from zero per side when the wing is level.

All my warbirds for years have been set up with toe out and anyone in my club will attest to how smooth my planes land. I never get the tank slapper landings thanks to this set up. Give it a try!

Keep in mind that we seldom get the opportunity to land directly into the wind. Proper approach techniques have much more to do with ground handling than we think. You can toe in or out till your blue in the face, but get a wing high into a cross wind and Katie bar the door. On take off as soon as the tail gets light any cross wind will weathervane your plane. Add another wing or two above lateral cg, the high angle of attack of the short couple WW1 birds and you have great video footage. That is why many WW1 flying strips where large open fields with the takeoff beginning center. Poor throttle control, no brakes for differential braking, and a tail skid rather than a steerable wheel made for some circus departures.
Spend a little more time evaluating wind speed and direction and preplan your setup and control inputs to counter, and much of the problem is controllable.

LOL some Japanese will do anything... something about being different :O

Many WW2 aircraft just have castering tailwheels. This is ok as they have brakes. A castering tail wheel on a model does not work, I tried it! lol I just wanted to point that out.

I always wanted to try the fixing the wheels to the axel trick, and I may possibly try Toe out one day as well. I am open to anything that helps. My Tripe does ground loop about half of the time. Mainly because of the wind.

Toe in is for cars ................... Toe out is for tail draggers !

Well........ yes............Many WWII airplanes do have castering tailwheels. But I'm unaware of any that do no lock for takeoff and landing. The castering function is used only for low speed taxiing and sharp turns in parking areas.

Dick

I understand this, but locking is not the same as steerable.

For cars, toe-in is for rear wheel drive; toe-out is for front wheel and all wheel drive. RWD has the front wheels drag the wheels straight; the power on a FWD AWD front wheels drives them froward. The idea with toe-in/ toe-out is when the wheels move the reaction will straighten the track. On race cars, toe out is sometimes used to make a solid axel RWD car oversteer some to counteract the natural understeer of a front engine RWD. Toe-in/out on a full size airplane depends on how it reacts one wheel on the ground while the other is in the air. Crosswind landing control is what they are after most end up with toe in. We dont have the ability to sit in the plane so models go with what dampens the most.