170A Tail Wheel Towing
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
170A Tail Wheel Towing
Is the tail wheel, spring and bracket assembly strong enough to handle the loads imposed by a garden tractor with a tow bar (which incapsulates the tire)? I feel pulling is of little concern, what about pushing.
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Tom Downey
- Posts: 285
- Joined: Thu Apr 25, 2002 4:50 am
I don't believe the tailwheel was ever intended to be pushed around with a towbar. Pulling it doesn't seem like much stress, but nonetheless it is not what it was designed for.
The L-19 tow-bar lugs which attach to the inside of the main-gear axles are designed for a standard tail-wheel towbar and are engineered for pushing/pulling these airplanes around by tugs. Those pn's are 0641102-1 and 0641102-2 (and I got mine from http://www.jtaco.com , but subsequent orders of various parts from that company were unsatisfactorily serviced. I'd first check Air Repair, Inc. http://www.airrepairinc.com/index.html and let 'em know you found out about them thru the 170 Assoc'n.) They simply bolt onto the main gear using the nuts which hold the axles on.
The L-19 tow-bar lugs which attach to the inside of the main-gear axles are designed for a standard tail-wheel towbar and are engineered for pushing/pulling these airplanes around by tugs. Those pn's are 0641102-1 and 0641102-2 (and I got mine from http://www.jtaco.com , but subsequent orders of various parts from that company were unsatisfactorily serviced. I'd first check Air Repair, Inc. http://www.airrepairinc.com/index.html and let 'em know you found out about them thru the 170 Assoc'n.) They simply bolt onto the main gear using the nuts which hold the axles on.
Last edited by GAHorn on Sat Oct 21, 2006 8:49 am, edited 1 time in total.
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
George,when you say "standard tailwheel towbar" I automatically picture the type that latches onto a Scott 3200. You obviously are referring to something more on an industrial scale.
These tow lugs look like they'd be handy to use as jacking points also. My friend Density Dog has something similar on his 180 for this purpose.
Hi Dog! You missed a good trip to Stehekin--we came back Saturday night instead of camping over cuz of wx concerns.
Eric
These tow lugs look like they'd be handy to use as jacking points also. My friend Density Dog has something similar on his 180 for this purpose.
Hi Dog! You missed a good trip to Stehekin--we came back Saturday night instead of camping over cuz of wx concerns.
Eric
The type tailwheel towbar that attaches to the Scott 3200 is a "toy" in my opinion. I've had one. I quickly sold it. (The purchaser seemed satisfied with it, however. As does many others. But the reason I found it unsatisfactory was because of the exact same reason of this topic of discussion. There's simply too much opportunity to injure the aircraft, because the tailwheel was neither designed for pulling upon nor pushing upon.)zero.one.victor wrote:George,when you say "standard tailwheel towbar" I automatically picture the type that latches onto a Scott 3200. You obviously are referring to something more on an industrial scale.
These tow lugs look like they'd be handy to use as jacking points also. My friend Density Dog has something similar on his 180 for this purpose.
Hi Dog! You missed a good trip to Stehekin--we came back Saturday night instead of camping over cuz of wx concerns.
Eric
The "standard" tailwheel towbar actually is shaped like a 12 foot long "V". The upper ends of the "V" have hook-attachments that latch into the lugs I posted above. The lower end of the "V" has an "eye" that hooks onto the tug's pintle-hitch. The aircraft is moved about in the same fashion as a tri-cycle gear airplane. (The two legs of the "V" are hinged at the "eye" so they can collapse towards each other and into a long "ll", when not attached to the aircraft. The upper ends usually have casters or dolly-type wheels to allow the towbar to be pulled around the ramp by a tug when an airplane is not hooked up to it.)
If you make such a towbar yourself, be certain to make the "V" out of square tubing, not round or pipe. Otherwise the unit will flex too much to be useful or controllable.
Although these lug are indeed sturdy, they are not actually designed to be jacking points.
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DensityDog
- Posts: 64
- Joined: Fri Jun 14, 2002 3:38 am
170 tailwheel towing
Hi Eric! Yes the 180 has "tow lugs" installed on the inboard side of the main gear axles. The prior owner put them there actually as a jacking point, as he was afraid of being caught out remote with no way to jack and repair a flat.
I have made a tow bar, much like George has, and it will fit on these jacking points. (I have also seen an AN clevis bolt in place of one of the axle bolts on each leg to be used as a towing point, to be used in this way).
If you tow your 170 a lot, I think this large tow bar is the way to go. If you watch how much your 170 tail wheel spring flexes when you tow it, especially when you pull 90 degrees to the c/l of the plane, you will see what I mean. The 170 tailwheel spring and bracket is not made to take this side load, at least not a lot.
Sorry we did not make it to Staheekin- weather has been great around here this week though! How was Con-krete?
I have made a tow bar, much like George has, and it will fit on these jacking points. (I have also seen an AN clevis bolt in place of one of the axle bolts on each leg to be used as a towing point, to be used in this way).
If you tow your 170 a lot, I think this large tow bar is the way to go. If you watch how much your 170 tail wheel spring flexes when you tow it, especially when you pull 90 degrees to the c/l of the plane, you will see what I mean. The 170 tailwheel spring and bracket is not made to take this side load, at least not a lot.
Sorry we did not make it to Staheekin- weather has been great around here this week though! How was Con-krete?
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
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David Laseter
- Posts: 156
- Joined: Sun Oct 13, 2002 11:24 am
One winter I had been pulling my 170B by the tail, with my truck, across a parking lot. It was cold out and there was a lot of frozen tire ruts in the snow. Somehow on a preflight I found that the tire didn't seem to rotate as normal. But I couldn't find anything wrong. Jeff Helmrik (Bud's son) kicked it and said it appeared to be fine. I had the local A&P look at it, no problems. Well it just didn't seem right, but I was a rookie.
FSS called me on the radio 10 mins after I took off and told me my tail wheel had fallen out of the sky. I'd never done a wheel landing before that day.
I was contacted by someone else who's Scott3200 did the same thing. Never heard how his investigation went.
I learned to trust my senses and do wheel landings that day.
Dave
FSS called me on the radio 10 mins after I took off and told me my tail wheel had fallen out of the sky. I'd never done a wheel landing before that day.
I was contacted by someone else who's Scott3200 did the same thing. Never heard how his investigation went.
I learned to trust my senses and do wheel landings that day.
Dave
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David Laseter
- Posts: 156
- Joined: Sun Oct 13, 2002 11:24 am
Oh yes, after I landed we threw the tail end of the plane into the back of a hatchback with the back window missing (my instructors). He got drunk and lost his CFI in another incident. He's a school counselor now. But the hatchback worked really well as towing equipment. If you go looking for one, try to get frontwheel drive.
Dave
Dave
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David Laseter
- Posts: 156
- Joined: Sun Oct 13, 2002 11:24 am
Scott 3200 problem
This is an email that I received a few yrs ago. Maybe someone can get something out of it.
David,
I own a 1948 Stinson 108-3, and recently had a Scott model 3200 tailwheel fail on takeoff, leaving the tailwheel behind. I didn't know about it until I landed. I managed OK with no additional damage to the airplane, even though it was a nighttime hard-surface landing in a gusty crosswind. Anyway, I read of your experience in the FAA Service Difficulty reports,
and as I am talking to Scott aviation about how to keep this from happening again, would like to know a little more about your case.
In my case, the pin that is cast as part of the upper tailwheel assmbly,
which is threaded to retain the lower housing, completely sheared due to "high frequency vibration - induced metal fatigue". Per your description, it sounds like this might be what happened to you.
Scott is telling me that they think these tailwheels should be completely
disassembled and inspected at least annually, and I'm trying to get them
to state a little more clearly what needs to be looked for, wear limits,
etc. I will file a Service Difficulty report myself when I learn more,
but I'd really like to know if this is a common problem.
I sent my tailwheel to Scott aviation, who contracted with an outside
engineering firm to perform a metallurgical analysis on the failed part.
They told me that they thought the tailwheel was an original, put on
in 1948 when the plane was built, and that it failed due to metal
fatigue. We're all familiar with metal fatigue, and I'm OK knowing
that nothing lasts forever. However, Scott has told me that a proper
inspection of the tailwheel would have prevented my incident. What I'm
asking them to do is publish something that describes what needs to be
inspected, how often, etc. They're balking at this (I think because they're afraid of any legal responsibility), and saying that the aircraft
manufacturer's service manual should cover this.
I don't know about the 170 manual, but all the Stinson manual says is to "inspect tailwheel assembly for general condition". In my mind, I think the tailwheel manufacturer should be able to tell me what to look for and when, particularly if they're blaming my incident on "poor inspection".
Anyway, they're telling me that mine is the only such incident, which clearly is NOT the case.
David,
I own a 1948 Stinson 108-3, and recently had a Scott model 3200 tailwheel fail on takeoff, leaving the tailwheel behind. I didn't know about it until I landed. I managed OK with no additional damage to the airplane, even though it was a nighttime hard-surface landing in a gusty crosswind. Anyway, I read of your experience in the FAA Service Difficulty reports,
and as I am talking to Scott aviation about how to keep this from happening again, would like to know a little more about your case.
In my case, the pin that is cast as part of the upper tailwheel assmbly,
which is threaded to retain the lower housing, completely sheared due to "high frequency vibration - induced metal fatigue". Per your description, it sounds like this might be what happened to you.
Scott is telling me that they think these tailwheels should be completely
disassembled and inspected at least annually, and I'm trying to get them
to state a little more clearly what needs to be looked for, wear limits,
etc. I will file a Service Difficulty report myself when I learn more,
but I'd really like to know if this is a common problem.
I sent my tailwheel to Scott aviation, who contracted with an outside
engineering firm to perform a metallurgical analysis on the failed part.
They told me that they thought the tailwheel was an original, put on
in 1948 when the plane was built, and that it failed due to metal
fatigue. We're all familiar with metal fatigue, and I'm OK knowing
that nothing lasts forever. However, Scott has told me that a proper
inspection of the tailwheel would have prevented my incident. What I'm
asking them to do is publish something that describes what needs to be
inspected, how often, etc. They're balking at this (I think because they're afraid of any legal responsibility), and saying that the aircraft
manufacturer's service manual should cover this.
I don't know about the 170 manual, but all the Stinson manual says is to "inspect tailwheel assembly for general condition". In my mind, I think the tailwheel manufacturer should be able to tell me what to look for and when, particularly if they're blaming my incident on "poor inspection".
Anyway, they're telling me that mine is the only such incident, which clearly is NOT the case.
C170 towbar
I have just fitted the towing lugs and tailwheel eye bolt to my C170A which were purchased from JTACO. The price was as advertised - LH $12 RH $18 Eyebolt $21 - the killer was the freight to Australia - $165.56.
Now comes the task of building the tow bar.
In an earlier post in this topic George offered the following description of a suitable tow bar:
The "standard" tailwheel towbar actually is shaped like a 12 foot long "V". The upper ends of the "V" have hook-attachments that latch into the lugs I posted above. The lower end of the "V" has an "eye" that hooks onto the tug's pintle-hitch. The aircraft is moved about in the same fashion as a tri-cycle gear airplane. (The two legs of the "V" are hinged at the "eye" so they can collapse towards each other and into a long "ll", when not attached to the aircraft. The upper ends usually have casters or dolly-type wheels to allow the towbar to be pulled around the ramp by a tug when an airplane is not hooked up to it.)
If you make such a towbar yourself, be certain to make the "V" out of square tubing, not round or pipe. Otherwise the unit will flex too much to be useful or controllable.
Two questions -
What would be a suitable size for the square tubing? and
What should the "hooks" on the end to engage in the towing lugs look like - just a long pin or should there be some sort of hook or latch to stop the "hook" from disengaging while towing?
David
Now comes the task of building the tow bar.
In an earlier post in this topic George offered the following description of a suitable tow bar:
The "standard" tailwheel towbar actually is shaped like a 12 foot long "V". The upper ends of the "V" have hook-attachments that latch into the lugs I posted above. The lower end of the "V" has an "eye" that hooks onto the tug's pintle-hitch. The aircraft is moved about in the same fashion as a tri-cycle gear airplane. (The two legs of the "V" are hinged at the "eye" so they can collapse towards each other and into a long "ll", when not attached to the aircraft. The upper ends usually have casters or dolly-type wheels to allow the towbar to be pulled around the ramp by a tug when an airplane is not hooked up to it.)
If you make such a towbar yourself, be certain to make the "V" out of square tubing, not round or pipe. Otherwise the unit will flex too much to be useful or controllable.
Two questions -
What would be a suitable size for the square tubing? and
What should the "hooks" on the end to engage in the towing lugs look like - just a long pin or should there be some sort of hook or latch to stop the "hook" from disengaging while towing?
David