rtfm
Well-Known Member
Hi,
My mate Bob and I are having a bit of a to-and-fro about this one. I might well have the wrong end of the stick (in which case I bow before you oh great Bob...)
The configuration I posed to Bob was this:
Is it possible to have a tricycle geared airplane with a single main gear wheel, and two nose wheels (configured like a tail dragger)?
His answer to me was no way. And he gave me many good reasons why not. Not least of which was that he'd tried it on his gyro and it hadn't worked.
But I need some closure on this, so I want to ask this group for its opinions also.
My reasoning goes like this:
Let's take a conventional tricycle gear plane. Main gear width = 8ft.
Now, halve the gear width. Will the plane still track the same? The answer is yes it will, but of course, it may be a little top-heavy because its stance isn't that wide. But the main gear will still track behind the front.
So we halve the main gear width again. Weight still distributed the same. The two main gear wheels are still behind the CG. Should still track the same.
Now, what if we reduced the main gear width to only 1 foot. Same weight distribution, CG still in front of the main wheels.
Of course, the plane would fall over, because there is nothing stopping it from doing so. But let's ignore that for the moment.
What if we now reduced the main gear width to nothing - ie had only a single wheel? Wheels still in the same position relative to the CG. The plane would still track true, because the CG is in front of the main gear. Or at what gear width does this suddenly change?
Problem is, how do we stop the plane from falling to one side? We could put little "balance" wheels on the tips of the wings to stop it falling over. Or we could put "training"wheels up front. Either way, it would stop the plane from falling left or right, but the weight of the plane is still definitely in front of the main gear, and so the plane would still track true down the runway.
In all this, the weight distribution still has the CG in front of the main gear. The back CAN'T swing round to the front. It can only do that if the CG is BEHIND the main gear. It doesn't make sense to suddenly begin talking about the front wheel as though it were the main gear. It hasn't moved, the CG is still where it always was, and the rear wheels are still where they have always been. Nothing's changed. Except that the width of the main gear is now very narrow.
The final step is to replace the single wheel up front with two , and space them quite far apart to give the plane some stability so it doesn't topple over. The CG is still in front of the main gear, so it will lead the main wheel(s). It can't help it. The fact that there are two wheels up front shouldn't make any difference. The wheels up front don't suddenly become the main gear...The main gear is still behind the CG.
What do you say?
Regards,
Duncan
My mate Bob and I are having a bit of a to-and-fro about this one. I might well have the wrong end of the stick (in which case I bow before you oh great Bob...)
The configuration I posed to Bob was this:
Is it possible to have a tricycle geared airplane with a single main gear wheel, and two nose wheels (configured like a tail dragger)?
His answer to me was no way. And he gave me many good reasons why not. Not least of which was that he'd tried it on his gyro and it hadn't worked.
But I need some closure on this, so I want to ask this group for its opinions also.
My reasoning goes like this:
Let's take a conventional tricycle gear plane. Main gear width = 8ft.
Now, halve the gear width. Will the plane still track the same? The answer is yes it will, but of course, it may be a little top-heavy because its stance isn't that wide. But the main gear will still track behind the front.
So we halve the main gear width again. Weight still distributed the same. The two main gear wheels are still behind the CG. Should still track the same.
Now, what if we reduced the main gear width to only 1 foot. Same weight distribution, CG still in front of the main wheels.
Of course, the plane would fall over, because there is nothing stopping it from doing so. But let's ignore that for the moment.
What if we now reduced the main gear width to nothing - ie had only a single wheel? Wheels still in the same position relative to the CG. The plane would still track true, because the CG is in front of the main gear. Or at what gear width does this suddenly change?
Problem is, how do we stop the plane from falling to one side? We could put little "balance" wheels on the tips of the wings to stop it falling over. Or we could put "training"wheels up front. Either way, it would stop the plane from falling left or right, but the weight of the plane is still definitely in front of the main gear, and so the plane would still track true down the runway.
In all this, the weight distribution still has the CG in front of the main gear. The back CAN'T swing round to the front. It can only do that if the CG is BEHIND the main gear. It doesn't make sense to suddenly begin talking about the front wheel as though it were the main gear. It hasn't moved, the CG is still where it always was, and the rear wheels are still where they have always been. Nothing's changed. Except that the width of the main gear is now very narrow.
The final step is to replace the single wheel up front with two , and space them quite far apart to give the plane some stability so it doesn't topple over. The CG is still in front of the main gear, so it will lead the main wheel(s). It can't help it. The fact that there are two wheels up front shouldn't make any difference. The wheels up front don't suddenly become the main gear...The main gear is still behind the CG.
What do you say?
Regards,
Duncan
