Can't Taxi Straight

Speaking of landing gear, I was going to take off from a road yesterday with my Commander 2. The problem was that the plane kept making a hard right turn under power, even though that brought it slightly 'uphill' and over the crest of the road. The blasted thing went farther sideways than forward. The landing gear is really cheap and loose, so I'm not sure how much adjusting I can do. Maybe change the direction that the wheels generally point...?

Reply to
mjc1
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"Toe in" seems to be the generic fix.

Reply to
The Natural Philosopher

A "hard right" would seem to indicate that perhaps the right wheel is not turning freely. Check it with a little weight on the wheel... if it is free, a bit of toe-in (or out) would likely cure the problem. Cheers, jc

Reply to
jc

Reply to
agpete

Then how will he learn to taxi and take off? Kinda like saying to somebody whose engine wont start to just push the car, isnt it? Just my opinion...

Reply to
Fubar of The HillPeople

He should hold the plane in his hand while waving it around in the air making motor noises. ;-)

Reply to
Vance Howard

Thanks for all the responses. Funny thing: reversing the landing gear, which puts the wheels on opposite sides, has no effect on the problem...

Reply to
mjc1

| Then how will he learn to taxi and take off? Kinda like saying to somebody | whose engine wont start to just push the car, isnt it?

... except that this sort of plane is meant to be hand launched. The landing gear is there and works, but it's sort of an afterthought.

But you can be a great pilot and have never flown a plane with a landing gear, let alone having taxied around and rose off the ground.

In any event, if the plane flies straight (this wasn't mentioned, but I'll assume it) but taxies crooked, that suggests that the wheels are crooked or one is dragging. Or perhaps there's a crosswind?

Toe-in can help make it more stable on the ground, but if it always veers to the same side, that suggests that the problem is not the sort of problem you correct with toe-in -- it's something more fundamental, something is assymetrical.

Reply to
Doug McLaren

Is this the one?:

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If that's how the design is built, it is going to be practically impossible to take off. The main wheels are WAY too far forward.

The wheels need to be placed slightly in front of the CG. Too far forward, and it will not go straight; too far back, and it will nose over. Since the propeller is so high up, the tendency to nose over will be stronger, so finding the sweet spot will be even more difficult than with a more conventional tail dragger.

Reply to
Robert Roland

I agree with Robert.

Here is an intuitive explanation of the problem.

The prop is where the thrust is effected, and in this plane it is about the same position (longitudinally) as the landing gear. Imagine trying to push a beam with free wheels at its ends using your finger. If your finger is perfectly centered, it will go about straight. If the finger is slightly off center, the wheels will turn very quickly and the beam will rotate. On the other hand, if you pull (or drag) the beam and wheels using a long, rigid stick instead (equivalent of having the landing gear way behind the propeller), it is much easier to control.

I had the same problem in an airplane. Past some threshold speed, the airplane would turn erratically when trying to taxi. My solution was to move the motor + propeller forward, thus increasing the distance between propeller and landing gear. This solved the taxi control and center of gravity problems at the same time. But you can't do the same with the Commander 2 easily, because it is a pusher.

Then I would seriously consider the option of hand lanuching it.

Happy flying!

Angel

Reply to
Angel Abusleme

Hmmmm ... I had the same results in my initial ground tests with a very similar aircraft.

After doing a LOT of reading here ... I believe that my ( and perhaps your) solution might lie in the fact that I was trying to take off under FULL throttle. Some suggestions on this forum, and on other groups, have indicated that these little planes just don't need full throttle. Using full power can cause them to cork-screw, either in the air or on the ground.

So, I'd just try taxiing slower and then very gradually increasing speed until it either takes off or goes back into the unwanted ground turn.

Take any and all of this post with a very large grain of salt since I am a rank newbie with virtually no hours under my belt. The radio that came with my beginner plane is giving me trouble ( it was a used plane and radio set ). Until I either replace the speed rheostat or find some other solution, I am grounded with that plane.

regards, Rich

Reply to
rich

Except that isn't how it works. There are many real aircraft using pusher arrangements and they're no harder to fly than tractor setups. An engine is mounted rigidly to a fuselage and points in whatever direction the fuselage points, so the thrust is always along the fuselage centerline whether the airplane is pushed or pulled. Your finger isn't rigidly mounted to the fuselage and its thrust therefore isn't kept in alignment with it. The OP just need to use the rudder to keep the airplane straight in the takeoff roll. It's all part of learning to fly.

Dan

Reply to
Dan_Thomas_nospam

You completely ignore moment arms - and clearly a tractor has a much longer moment arm than any pusher. That means the tractor is intrinsically more stable under thrust than the pusher - and that difference could indeed aggravate an inexperienced driver...

/daytripper

Reply to
daytripper

Here's a corollary: it is much easier for an inexperienced driver to negotiate snow-covered roadways with a front wheel drive vehicle than a rear wheel drive...

/daytripper

Reply to
daytripper

On Tue, 25 Sep 2007 17:17:53 -0700, Dan_Thomas snipped-for-privacy@yahoo.com wrote in :

I have a feeling that the plane has ruddervators rather than rudders.

I may be wrong.

But if so, they may give less control on the ground than a rudder mounted on the vertical fin.

Marty

Reply to
Martin X. Moleski, SJ

I've seen videos of stock Commanders taking off ok, and read reviews in which they did so. I'm nonplussed about why mine is so squirrely.

Reply to
mjc1

What about bending the landing gear to relocate it slightly rearward...?

Reply to
mjc1

That's easy to try, and I will, and report back. Thanks for thinking about it.

Reply to
mjc1

:

True on both counts. They seem to be useless at low taxi-ing speeds.

Reply to
mjc1

On Wed, 26 Sep 2007 03:35:32 GMT, "mjc13" wrote in :

Standard aircraft get prop wash over the rudders.

Another factor in your case may be that the ruddervators are not solidly in that airstream because of the location of the propellor.

Marty

Reply to
Martin X. Moleski, SJ

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