Mooney Power Tows

[DaV8or]

Quote: DonMuncy

Well, I finally got my power tow finished. I now consider myself an expert on tow design, parts acquision, assembly etc. There are a few things I would change if I were doing it over, but it looks pretty good, is easy to maneuver, and works well (albeit slowly). If you are adept at welding and have lots of spare time, I highly reccommend the project. I'm very willing to share my problems and results.

Don

[Carl S]

Quote: DonMuncy

Well, I finally got my power tow finished. I now consider myself an expert on tow design, parts acquision, assembly etc. There are a few things I would change if I were doing it over, but it looks pretty good, is easy to maneuver, and works well (albeit slowly). If you are adept at welding and have lots of spare time, I highly reccommend the project. I'm very willing to share my problems and results.

Don

[Carl S]

<edit> Double Post </edit>

[Geoff]

This might seem crazy but instead of $1200 for a towbar, I bought a clapped out golf cart for $500 off craigslist and a towbar that mounts to the front for $100.  The upside is that the golf cart gets used for trips around the ramp.  The downside is its tough to fit in the plane.

[DonMuncy]

I will make a picture of my tow hooked to the plane and post it. When you see the picture, you will see that the handle sticks up pretty close to the spinner. It is not a real problem, but is not ideal. For that reason,  I would make the angle between the structural parts at 100 degrees rather than the 90 I used.

I have about $400 in it, but that could be beat some. The winch cost $130, but you can catch one like it (at least it seems to be) for $60 on sale at harbor freight. I also paid $50 for machining on the "reel" for the winch, because I don't have a metal lathe or a friend who has one. The battery was also overpriced at about $80.

Other than the angle situation above, my only complaint is the slow speed. I am seriously considering playing wth the sprocket sizes to see if I can make it faster (and still have sufficient power). They make bigger winches, but I didn't want to make it any heavier than necessary.

One of the really nice touches is that the winch has a "disengage" mode, so you can disengage it, free-wheel it up to the plane and attach it, then engage it to tow. It someone plans on making one, this is very important, as otherwise, it would be a PITA to skid it into place.

I have diagrams, measurements, parts lists etc. if anyone is interested.

Don

[DonMuncy]

For those who wanted to see a photo of my tow attached to the plane.

Incidentally, today I changed the sprocket size and it now runs at a speed much more to my liking.

Don

[DaV8or]

I can see what you're saying about the handle angle. Making it over, sure, change the angle, but now that your's is done, just cut the top of the handle above the motor and fix the angle. v 1.5  All in all, great job! Does the new gear ratio effect battery charge much?

[DonMuncy]

Thanks for the input Dave. It really isn't bad using it with the handle angle the way it is. I just wanted to make anyone who wanted to copy it aware of a possible improvement. Or if someone popped up who wanted to buy this one for the cost I have in it, I would build me another with the improvements.

My wife asked if I was going to sell these. I told her there was no way I could turn enough profit on them without selling them for about the same price the commercial ones cost.

As to the gearing, I have been unable to detect any difference in battery life. Actually, I suspect I overdid the battery somewhat. I used a 20 Ampere hour battery. The specs for the winch says that at full load, it pulls 70 amps. So even at full load, that should equate to a little over 15 minutes. Unfortunately, I don't have a good meter to measure the load. I suspect it is not close to full load, but that is just a WAG.  Anyway, I would be interested if anyone would build one with a 5 amp hour battery (cost about $20), and see how it goes. That would substantially reduce the cost to turn one out, if it would work.  

Don 

[Bacachero]

awesome tow!

You should get an award for creativity! Thanks for sharing...

[Piloto]

Very nice design Don. I would keep the battery capacity as much as practically possible. As the battery ages it looses storage capacity. I have noticed that the trend for towing devices is to go electrical instead of gas engines. Too many problems with the gas driven tows.

José   

[DaV8or]

Quote: DonMuncy

 Anyway, I would be interested if anyone would build one with a 5 amp hour battery (cost about $20), and see how it goes. That would substantially reduce the cost to turn one out, if it would work.  

Don 

[DonMuncy]

For those of you keeping up with my power tow unit, I finally engineered and implemented a system to avoid having to get down on one knee to attach the unit to the plane. It works very well. Now if I can just figure out how to engage and disengage the "free wheeling" device without having to bend over...

Don

[Amelia]

I have a Power Tow, bought it from a neighbor down the ramp, and it works just great- this ol' gran'mama can haul her 20K out of the hangar and put it back with the greatest of ease.

[blacknchrome]

Don, Thanks for the update.  That's a great looking, simple design.  I may be in contact at some point to get the details and build my own.  If you do decide you want to sell it to build an improved model, let me know. 

 

[DaV8or]

Excellent mod! Getting better and better. I really needed a power tow fast and I needed one that I can put in the plane and take with me, so I bought the Redline Sidewinder, but if that weren't the case, I would be definately be looking for your plans.

[DonMuncy]

For those of you who have kept up with my tug design/build, I have added what I think may be the last change. When I originally built it, I had to get down on one knee to attach the unit to the tow tube on the plane, and also when I needed to engage and disengage the drive mechanism. The latter was necessary because you have to put it in "free wheel" mode to move it to the plane and hook it up, then engage the drive to move the plane, and then disengage to remove it.

I posted my modification to operate the attach mechanism from the handle. After Bill Bergman built one similar and included a modification, I have built a mechanism to engage and disengage the drive mode from the top. I am really happy with it. No more bending over to use it.

As always, glad to share info if you are interested.

Don