Keep your pants on...

[bcg]

OK, so it's not completely Mooney related, although it would move a Mooney around just fine.  I wanted to share my early progress on a portable tug that would be universal and work on planes with wheel pants and probably tail wheel aircraft as well.  I think I'm going to call it The Keep Your Pants On Tug.

I'm most of the way there, I just need to get the handle and wiring done.  It's going to break down into 3 pieces, the longest being 36" which could be split into 2 separate pieces, and should weigh in at about 30 pounds with batteries.

What do you guys think?  There was lots of good input on the Mooney tow bar, I'm hoping that will be the case here as well.

[Paul Thomas]

Is the idea to tip the platform, use the winch to get the wheel on the platform, and then power to the wheel will drive it around?

If so, I would add an hinge to the platform so that you don't have to tip it over. Or build the platform with small wheel in the front, and larger ones in the back so that you can get the airplane on without having to do the tip over.

You may need from R&D on what size chock is high enough on the front, yet low enough to clear wheel pants.

[bcg]

Just now, Paul Thomas said:

Is the idea to tip the platform, use the winch to get the wheel on the platform, and then power to the wheel will drive it around?

If so, I would add an hinge to the platform so that you don't have to tip it over. Or build the platform with small wheel in the front, and larger ones in the back so that you can get the airplane on without having to do the tip over.

You may need from R&D on what size chock is high enough on the front, yet low enough to clear wheel pants.

Yes, the platform is already on a hinge just past the middle so that it naturally sits in the support but it tilts as soon as there's any weight put on the front.  I might have to make the plate a little longer so the angle isn't as extreme.  I modeled this after a tug I saw in use, it had a much longer plate. 

I've played with the idea of mounting the wheels up higher to put the plate lower but, I'm worried about not having enough ground clearance to get into a hanger over door rails and a concrete lip.

[FlyingDude]

I like how you built it.

However the wheels are too small for the connection cracks in the concrete slab and for the step between the slab and taxiway asphalt...  That's for my hangar. Ymmv

[Pinecone]

It looks like a pretty steep angle to pull the plane up

[bcg]

Just now, Pinecone said:

It looks like a pretty steep angle to pull the plane up

It may end up being too steep, I won't know until I try it.  You've got to remember that as the weight moves onto the plate, it's going to tilt back down and lift the plane so you're not really pulling it up that angle.

[MikeOH]

1 minute ago, bcg said:

It may end up being too steep, I won't know until I try it.  You've got to remember that as the weight moves onto the plate, it's going to tilt back down and lift the plane so you're not really pulling it up that angle.

Hmm,...maybe.  It seems like all the nose wheel weight will act vertically through the centerline (hub) of the wheel.  So, until that force moves past the hinge on the platform the torque is going to keep the platform at the steep angle.  That is, it will have to climb half way up the platform before the platform levels.

Hopefully, testing will prove me wrong!

[bcg]

Just now, MikeOH said:

Hmm,...maybe.  It seems like all the nose wheel weight will act vertically through the centerline (hub) of the wheel.  So, until that force moves past the hinge on the platform the torque is going to keep the platform at the steep angle.  That is, it will have to climb half way up the platform before the platform levels.

Hopefully, testing will prove me wrong!

We'll find out soon enough...   I can always make it longer or put it closer to the ground if I have to.   I want avoid longer if possible.

[Paul Thomas]

I think you will need longer due to wheel pants, the wheel will come up but I'm worried about the fiberglass hitting. Some owner have their wheel pants really low to the ground by design... although I'm not sure how many RV10 owners you would get. I would design something that works with Cirrus wheel pants and you should be good to go with most others.

Testing and figuring out what works and does not is part of the fun and frustration.

[Parker_Woodruff]

If you were to stop the tug, make sure the plane won't keep rolling over the lip.

Agree with the above comment about the castering wheels needing to be bigger to handle a lot of the hangar rails, pavement cracks, etc.

[bcg]

Just now, Parker_Woodruff said:

If you were to stop the tug, make sure the plane won't keep rolling over the lip.

Good point, I can add a vertical plate up front to prevent that.

[ta2too]

2 minutes ago, bcg said:

Good point, I can add a vertical plate up front to prevent that.

Given the height of the winch mount, along with a 1 ton capacity, I don’t think you will have a problem. 3” or 4” caster wheels would be great.

Sign me up if you intend to sell them!

[Pinecone]

16 hours ago, bcg said:

It may end up being too steep, I won't know until I try it.  You've got to remember that as the weight moves onto the plate, it's going to tilt back down and lift the plane so you're not really pulling it up that angle.

Not until the nose wheel gets to the hinge point.

[Pinecone]

I think it might be better to make a flat plate that lifts up. 

I think that steep angle will not clear the pant.

[bcg]

Maybe this will work.

I'm trying to keep the plate compact to keep it portable.

Raising and lowering the plate as a whole would definitely work well, I just don't know a way to do it that won't become bulky and expensive. I'm open to suggestions.

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[A64Pilot]

If you put a lazy susan on the plate, then you couldn’t hurt the truss, and you could turn as tight as you wanted too.

I think you’re onto something. I think you need to get the plate much closer to the ground, you could do that by placing the wheels axles well above the plate as opposed to under it, that would also allow you to pay like 4” pneumatic tires on it so it would roll easily over most anything

[wombat]

I've been noodling on this topic for a while myself.   I think you can put a lazy susan type of platform really low between the arms of a wheel dolly like one of these: https://www.google.com/search?q=wheel+dolly 

At that point you can put as large of casters on as you want.   You could have two, three, or four of them, and potentially drive with some of the casters if you wanted, or have it mounted fixed to the front of a lawn tractor or something.   

You would want the back half of the lazy susan to have a chock on it so the wheel does not roll off the back side.  Maybe just a small bar or fence around the back half.  And probably have it lightly spring loaded so it returns to 'forward' when there is no aircraft on it.    

You'll also want a way to keep the aircraft on it regardless of orientation relatively to the rest of the structure.  I was thinking an arm that locks into place behind the wheel, controlled by a push-pull cable like one of these:  https://www.google.com/search?q=flexible+push+pull+cable    The lazy susan will never need to rotate as much as 180 degrees even, so as long as you leave some slack, this will work.

You also need to have some way to pull the aircraft onto it.  You could have it be the same device as the thing that holds the aircraft on, basically a rod that is extended behind the wheel that when you pull on the lever, pulls the aircraft towards you.

You could as an option, include something to raise and lower the lazy susan so rolling onto it is easier.

 

One limitation of this design is that when you to to offload the aircraft you'll need to be at least reasonably close to directly in front of it.  You can't pull the tug out sideways.

[Pinecone]

21 hours ago, bcg said:

Maybe this will work.

I'm trying to keep the plate compact to keep it portable.

Raising and lowering the plate as a whole would definitely work well, I just don't know a way to do it that won't become bulky and expensive. I'm open to suggestions.

Sent from my Pixel 9 Pro XL using Tapatalk

If  you put the plate low enough, maybe just a ramp to run up.  And the ramp could be hinged to be the rear chock

[bcg]

27 minutes ago, Pinecone said:

If  you put the plate low enough, maybe just a ramp to run up.  And the ramp could be hinged to be the rear chock

I've got to get some measurements of the door rails and lip heights when I go to the airport today.  This currently has only 2" of ground clearance, which seems pretty low already.  If I only need an inch to clear normal obstacles though, I can drop it some.  The challenge is finding the sweet spot where loading the plane is easy and it's not going to get stuck when you try to go over something.  I can probably cheat some of it by placing the wheels where the hinge for the plate is since it's the lowest part.

My thought is that the winch remains attached until you're ready to unload so you don't need to chock the back side, just the plate in the front to keep it from rolling forward when you stop the tug.

[Fly Boomer]

13 minutes ago, bcg said:

My thought is that the winch remains attached until you're ready to unload so you don't need to chock the back side, just the plate in the front to keep it from rolling forward when you stop the tug.

Seems like the winch would pull the wheel up onto the plate even with a significant angle (assuming the plate tilts).  In other words, I'm not sure you need to lower the plate, and risk dragging on something.

[Paul Thomas]

2 hours ago, Fly Boomer said:

Seems like the winch would pull the wheel up onto the plate even with a significant angle (assuming the plate tilts).  In other words, I'm not sure you need to lower the plate, and risk dragging on something.

It will and doesn't take much force. The issues are wheel pants and a place to attach the winch to the airframe.

[bcg]

It will and doesn't take much force. The issues are wheel pants and a place to attach the winch to the airframe.

The FBO and shops I've seen using these always attach to the gear above the wheel pants. They just wrap that strap around it.

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[bcg]

Well, that didn't work but, none of us correctly predicted where the problem would be.  The plate height worked fine with the 2 different sets of wheel pants I looked at, the problem came when winching the nose wheel on.  As soon as there was real tension on the rope, it started bending at the hinge instead of pulling the plane up the plate.  I should have seen that coming.  I need to enlarge the plate a little to feel comfortable with this and I'm going to have to relocate the winch to the part that the plate is on so there's no option for the winch other than pulling the plane onto the plate.