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$ 5000 Tug

blackbeard10

Well Known Member
My hangar neighbor has one of those 5 grand tank tread radio controlled tugs.
Call it my RV tug grin when I pull out my 4 with this little gem. Owe the design to another VAF contributor. Let's see... recycled Jazzie power chair wheels and motors (Ebay), recycled plywood from an old workbench, two way momentary switch for forward and reverse, 12 v car battery castoff from my wife's Volvo and a non reliable Odyssey battery for 24 total volts and some other odds and ends. Drum roll......$ 92.78.
Massive power and I still have $ 4,907.22 to spend at SteinAir.
 

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Awesome!

That is truly glorious. Would love to see more photos if you get a chance. None of us is getting any younger, and I'd wager few of us have improving back conditions....
 
Nice! But i'm docking 10 points for standing your cordless drill on the drill bit. :(

If that's going to hurt the tool, then it's probably not a very good tool! Try a couple 10' drop tests on the tool then pass judgement, haha.
 
RV Tug

I will post some pics and measurements later. It will work on 12 volts but does not have enough power, so two 12v batteries in series works fine. I used 12 ga. auto wire at first but it got a little warm so I doubled all of the runs and problem solved. Used a left over momentary on-off-on switch which works fine but be sure to mark the direction Forward/Reverse or you get a hard punch in the gut!!
You could get fancy and install a reostat throttle grip (Amazon) but just momentary pulsing works fine. Simplicity!
The handle is 3/4 pipe and fittings and the handle swivels on the base for storage but still works well. The key is the use of the Jazzie wheels. You will need to cruise eBay periodically for a matching pair that includes motor, wheels, and tires.
I got mine for around $ 85. I leave the tire pressure a little low to get good traction. The angle that slides under the tail easily slides under the wheel when you drive it up. At first I tried just the T handle quick release pin to keep the wheel engaged...the wheel jumped out on pulling. So I use the nylon cord wrapped around the tailwheel shaft and slip it over the bolt with carabiner for a keeper.
This could be improved (you engineers have at it) but it works fine for me and keeping with Steve Melton's theory of simplicity I'll stick with this method. I am finishing up a Zenith 750 Stol Nose dragger project and I will build an adapter to engage the nose wheel to move the 750. It should work fine. Again I want to thank the original VAF post for posting his version.
The drill fell over...not stored. :)
 
TUG PHOTOS ETC.

In order not to clog up Doug's site, please go to https://www.flickr.com/photos/187537445@N08/?
for more photos and measurements some measurements did not show up well width of platform 17.5 " C channel is 7' long 1.5 deep and 2.75 wide
And yes, I should have at least some shrink tubing on the switch contacts for safety reasons. Note drill :-}
 
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I'd suggest that you can save $92.78 just by using your 13 year old as your tug, but the grocery bill is a lot more than $92.78 a week.
 
Which one is the one that goes for $5000? :)

This one.

I have one for my C180 and it works very well. My hangar has a bit of a lip at the door and this pulls it over that, which I can't do myself, easily.

I also have an electric wheelchair that has been modified into a stand-up person vehicle. I tried to make it into a tug but although it had enough power, I didn't get the connection right and ended up with a tug that did not push the C180. The problem was that I attached a towbar to the chassis rather than lifting the tailwheel. The angle tended to cause a lift force on the chassis which reduced traction. The hangar floor is somewhat slick.... no joy.

Its batteries have since died and I'd be glad to sell it and the charger. But I'm keeping the fancy tug.

Dave
 
Put the forward / reverse toggle switch on like they do for powered vacuum cleaners.......................

You may be able to expand that for 2 switches (one for each wheel) so it will turn too...........
 
A little bit of reading (very little) says there is a huge robot industry out there focused on STEM education and plain old fun. Chair motors are popular. The supplier says current draw is about 35 amps, maybe more near stall, so we can't use just any old ON/OFF switch, even if one speed is OK. Moving to speed and directional control requires a motor controller (readily available), which feeds each motor individually, switching and modulating up to 30V and 60 amps based on low voltage inputs. Those inputs range from simple analog voltage, to RC using off-the-shelf Tx and Rx, to autonomous operation.

Yeah, I've already ordered a set of motors and wheels. I'll stick with a towbar style frame with a T-handle for the operator, as I don't want to deal with the long term battery and hardware issues of RC. I'll lift the tailwheel at a point just forward of the drive wheel axis, so the operator pushes down lightly on the T-handle. The idea is max available weight on the wheels for traction. Based on experience with the cheap drill-powered towbars I built for two buddies (below), I suspect a a four wheel chassis would not climb up over my hangar rails without wheelspin.

I do want speed control, and a small degree of directional control so I never have to drag a wheel. So, current plan is a center mounted joystick on the T-handle, or Plan B, two twist grips, left and right, with a separate forward-reverse switch. If I can find twist grips intended for forward-reverse control (spring loaded to the center of their rotation range), the motor controller can be set up assume 2.5V is stop, with 0V being full reverse and 5V being full forward.

BTW, the two drill-powered towbars are still working fine, dragging an S-7 and Legend Cub. A drill with a really big battery would be more convenient, but the big DeWalt corded drills are bulletproof, less money, and the cord has not been a serious issue in practice. Axle is from an electric snowblower.

POSTSCRIPT: Just looked at Jason's post above. Yeah, yeah, something like that, right down to the Sabretooth controller! Jason, where did you get the joystick box with the display?
 

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These videos have appeared on the site before. I am writing an article for Kitplanes on their development. Delayed by some health issues and my computer going to heaven with a bunch of stuff.

It will not be a detailed construction article, rather enough details so that a savvy builder with access to a fairly complete shop could duplicate one. There are several unique features that make them “load” the wheel and retain it, even with the usual tight Vans fairings.

The two drive wheel version is sort of ok for the two place, the four drive wheel is necessary for the -10.

I am not the designer/builder of these, but I have had some input. He is an amazing hands on designer but not a writer so I am doing that part.

https://youtu.be/5E6MthAqOMw

https://youtu.be/ella7_dpEG8
 
to each his own

I built mine in a short morning. It worked great. Then I went flying.
 

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When Will Article Publish?

These videos have appeared on the site before. I am writing an article for Kitplanes on their development.

It will not be a detailed construction article, rather enough details so that a savvy builder with access to a fairly complete shop could duplicate one.

https://youtu.be/ella7_dpEG8

Bruce,

I love the 4 wheel model. Might be just what I want for my RV-10. Any idea when the article on this might publish in Kitplanes? Any plans to provide/sell more detailed plans for it?

Thanks
 
Wheels?

This is an interesting thread, and I plan to build some type of tug now that my -9A is done. I have ordered a couple of eBay Jazzy gear motors and a motor controller. Can someone tell me where to get the wheels that attach to the driven axle shaft? Are they splined? Thanks.
 
Not fair! You gotta give closeup shots so we can steal your idea.

It was a proof of concept , just like many of my ideas they die in the lack of funding pool :)


Jazzy motors ,Sabertooth motor controller, hc-02 Bluetooth module, and ardiuno uno; are the basics of it.
 
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Finished this AM. Works fine on the shop floor. Left-Right function is perhaps a bit too sensitive, but I'll get it to the hangar this weekend and see if it's a practical concern.

Yeah, grand overkill, but hey...
.
 

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A work of art

Looks dangerous! At least it looks like it has lots of torque. It looks strong enough to pull and push fat bottomed girls like Harvards & Corsairs. The axle bolt hooks probably only fit RV size TW

I expect it works as good as it looks.

Check PM's
 
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Finished this AM. Works fine on the shop floor. Left-Right function is perhaps a bit too sensitive, but I'll get it to the hangar this weekend and see if it's a practical concern.

Yeah, grand overkill, but hey...
.

I LOVE the color!!!
But I have a nose wheel and a ramp into the hangar. What ever shall I do :).
 
Nose Wheel Version

Dan and I have been in loose formation in building our respective tugs. I just gave mine its first test in pulling the airplane on Sunday, and am very happy that I won't have to deal with pulling the plane in and out in the winter any more... I have a few clean up electrical items to complete when warmer weather comes, but it is fully usable now. I'll add a light to it, both for illumination in the dark, but also as a power on indicator.

I swiped a lot of ideas from others for this design, and picked away at the mechanical design on and (mostly) off for a good part of 2020, mostly iterating different concepts, and then refining the concept I selected.

The pictures are mostly self explanatory, but here are some details: two 18 amp-hr AGM batteries, a PWM motor controller, a twist grip throttle, a momentary contact, three position switch under the left handlebar for forward or reverse (letting go of this switch stops the tug), a 24v transaxle with differential from a mobility scooter (ebay). The wheels with sprockets were bought new ready to go. Third wheel is a castering type.

The nosewheel is pulled up onto the tilting platform, and when it is almost to its final position, the platform tilts to horizontal as the nose wheel rolls "over center". The platform is then about 1.5 inches above the ground. The pull yoke is clamped against the red cross bar to completely stabilize the nosewheel, preventing any motion due to asymmetric main gear drag. I put the nose gear caster axis as close to the tug's wheels as was practical, so that swinging the tug back and forth creates minimum tail motion. Why some of the pictures rotate 90 degrees will (for me) remain a mystery (I know someone kindly posted how to fix that).

Here are a couple videos of it in action:

Video 1

Video 2
 

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Cool projects. I have been planning on building one of these at some point. Nice to see peoples designs.
 
I LOVE the color!!!
But I have a nose wheel and a ramp into the hangar. What ever shall I do :).

Finish the tailwheel airplane?

two 18 amp-hr AGM batteries, a PWM motor controller, a twist grip throttle, a momentary contact, three position switch under the left handlebar for forward or reverse (letting go of this switch stops the tug), a 24v transaxle with differential from a mobility scooter (ebay).

Or of course, copy Alex, who has some great ideas here. I originally wanted the twist grip throttle, but could not locate one with a potentiometer spring loaded to center, the operating scheme for the fancy Sabertooth controller. Alex sidestepped the issue with the forward-reverse switch and a much less pricy controller. The differential in the axle allows turning without resistance, an overlooked detail. For example, the cheap tugs built with the snowblower gearboxes are indeed resistant to a sharp turn when loaded. Flip side is that one wheel may spin, but Alex has since run it in the snow and it does not seem to be a problem. Steering via independent motors doesn't have that issue, but brings us back to the human interface (currently a joystick) and controller choice.
 
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Thanks Dan, for the kind words.

Regarding the PWM and twist grip controller... The twist grip came without any documentation of any sort (can't complain - $20 to my door for it and the other matching grip). I figured out it has a Hall effect sensor and not a pot. I was able to supply it with 5v, which conveniently, was what was being supplied to the pot in the PWM. The sense, however, was wrong (full speed was throttle idle...), but I was able to reverse the physical orientation of the magnet in the throttle. Electronics geeks could easily deal with the incorrect sense with a simple added circuit. I also have a small idle thrust, as it were, because of this hack fix, but it is very slow and not going to be a problem.

Long story short - get a motor controller designed for this type of throttle, they are numerous on Amazon (designed for scooters, bikes).

The PWM I used has a built in set of relays for reversing the motor direction, so the momentary contact switch only carries signal level currents.
 
Very Cool Tug!

This looks like the perfect drive train for the "Dr. Evil Chair" that I would like to build. Maybe it should be a Dr. Evil Chair with a tow hitch on it, for towing planes. Muhhh aaah haaa haa haaa!
 
Finished this AM. Works fine on the shop floor. Left-Right function is perhaps a bit too sensitive, but I'll get it to the hangar this weekend and see if it's a practical concern.

Yeah, grand overkill, but hey...
.

Looks like the makin's of a KitPlanes article to me........ ;)
 
A non-engineer's simpler approach

I hesitated to post this with all the impressive engineering done by others. Not being nearly as talented, I took a much simpler approach. Since wheel chair motors are a favorite drive mechanism, I started with a used wheel chair, this particular model - a Jazzy Select 6 (photo 1) - comes complete with motors, wheels, motor controllers and stick control, all connected.

I then removed the seat, and created a simple mount on the seat base for the handle of my Bogert tow bar (photo 2) with a hinged cover that pins in place (photo 3), locking the handle of the tow bar and allowing push or pull.

Finished set up - photos 4 & 5

I disconnected the seat rotation stops so the tug can pivot 360 degrees. The tug (and chair suspension) works best in its native "forward" direction - the pictures here would therefore be the tug position for "backing up" the aircraft. Rotate the tug 180 degrees for "pulling" the plane forward. The stick control, removed from the chair arm, has a 5' cord - perfect for walking behind/beside the tug. On my slick hangar floor, traction is an issue, particularly at start up. I reinstalled the foot rest for the wheel chair and as power is applied, I can step on the step applying 150 pounds of ballast that gets the tug moving. An improvement would be built in ballast.

I have found this setup easily accomplishes my goal of a tug for my hangar ramp (gentle - about 2 degrees), but is trickier (non-intuitive) for close maneuvering - like turning the plane around and backing it into place - it will do it, but requires some spinning of the tug to swing the handle, and its just easier to disconnect for the final parking.
 

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I have found this setup easily accomplishes my goal of a tug for my hangar ramp (gentle - about 2 degrees), but is trickier (non-intuitive) for close maneuvering - like turning the plane around and backing it into place - it will do it, but requires some spinning of the tug to swing the handle, and its just easier to disconnect for the final parking.
Great work! This solves the problem of the "universal interface" to the aircraft - a tow bar handle. When you have to move a lot of different types of aircraft, this is a big advantage. What did the used wheelchair run? Where I am they are quite expensive.
 
Great work! This solves the problem of the "universal interface" to the aircraft - a tow bar handle. When you have to move a lot of different types of aircraft, this is a big advantage. What did the used wheelchair run? Where I am they are quite expensive.

Craigslist has 'em from $250 to $1500 locally.

The other thing to look at (IMO) is the series of devices known as powered trailer dollies. Here's an example. Others can be had for under $1k:

https://parkit360.ca/collections/tr...RHz7mff1phle82PDLFLlnSEyQT-nvoDhoCRd4QAvD_BwE

Yeah, more than a $300 DIY job, but pretty good compared to a $2-3K commercial aircraft tug.
 
Mickey:

What did the used wheelchair run? Where I am they are quite expensive.

I first looked on eBay - typically $500-$1000, but local pick up only (expensive to ship). So then I went to Craig’s list - similar prices, but I got this one for $250.
 
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Leave the seat on it.

This may be an option. The seat was already off and the handle mount in its place when I realized the traction issue (it weighs 150 lbs without the seat so I hoped it would be okay). The ideal weight position is on the seat post (I sometimes stand there too) - I would then need to figure out a way to easily secure the handle under the seat front - doable I think.
 
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