Long Pawl vs Short Pawl on ABW 3200 TW

How to keep the Cessna 170 flying and airworthy.

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TerriM
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Long Pawl vs Short Pawl on ABW 3200 TW

Post by TerriM »

Quick question for you mechanical experts.... I have a 3200 Baby Bushwheel on my 170B. How does the short vs the long pawl impact handling? I'm about to order new parts for my worn out tw assembly and need to decide on long vs short pawl before I place my order via Alaska Airframes. Thanks in advance! Terri
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Bruce Fenstermacher
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by Bruce Fenstermacher »

Are you talking about bent up control arms VS not bent?

If you are there has never been a large enough report from those that have the bent up arms, that there is an improvement over the non bent arms. At least big enough that we recommend them as an improvement. This is not to say they hurt either. In theory the turned up arms would create a better pull angle for the control chains and in theory improve control. As I said this has not been born out that I'm aware. Maybe because the upturned arms now have a twisting action on them negating any improvement.

If your not talking about this then, disregard.
ABI-3214-00-1.jpg
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bagarre
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by bagarre »

https://www.airframesalaska.com/3200-Se ... -3200a.htm

3200-ABI-3219-02 Long Pawl
3200-ABI-3219-00 Short Pawl

If I'm looking at it right, the long pawl will cause the tailwheel to unlock sooner than the short pawl.

Not sure which is original but I'd call ABW and get their opinion.

While you're at it, replace the grease seals with theirs.
3200-ABI-1863 <- much better than the original felt seals.
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TerriM
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by TerriM »

Thanks guys. I understand that the long pawl will free the TW sooner. I should have been more specific....I'm looking for someone that has used both long and short pawl to get the pro and cons. My thought is that the shorter one would give me better control. Thoughts?
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by bagarre »

I haven't used both to know the difference and don't know if the stock pawl is the short or long.
If I had to guess, I'd get the short one to keep the tailwheel locked longer. But, that's a guess.
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TerriM
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by TerriM »

Hi Bruce,

Your reply relates to the steering arm assembly. Although my question was about the pawl, I do appreciate your suggestion. Last week, I noticed that the angle of the pull chain is not ideal as it pulls upwards. To improve responsiveness of my tw, I plan to order the steering assembly with the bent up arms. Good to know you recommend it! This give me more hope that it will be helpful!

Back to my original question.... During my shopping on Alaska Airframes website for a new TW head and pawl, I learned there is both a long and short pawl. Not knowing which I should order to achieve optimal steering, I thought I'd reach out to you folks on the 170 site that have more experience. Others may respond with the plus and minus of each....

Thank you!
Terri
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n2582d
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by n2582d »

Terri,
I wasn’t aware there was a short and a long pawl until recently when I read this.
Gary
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TerriM
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by TerriM »

Hi Gary, I did not understand how the tail parts worked, or the names of the parts, until my friend drew me pictures this week. Everyday is a new learning experience for me. I enjoy learning and working on my plane as much as flying it.
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DaveF
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by DaveF »

From the pics, I'd guess the stock pawl is the short one.

My tailwheel assembly has the upturned steering arms. If the upturned arms work better, I'd hate to use the flat arms!
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gfeher
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by gfeher »

The current short pawl has the same part number (ABI-3219-00) as the pervious standard pawl when ABI offered just one pawl. The long one appears to be the new option. As far as swiveling/castering goes, I have the standard Scott pawl on my plane and I'm satisfied with the point where it free casters. So would be hesitant to change the pawls. But, I don't have any experience with the new pawls.

I just removed, cleaned, inspected, and re-packed my tail wheel assembly about a month and a half ago. Terri, I suggest that when you re-assemble yours, you follow the procedure in the Cessna 10-24-50 S.N.L. for tightening the kingpin castle nut. As it states in the service letter, the assembly has a friction type shimmy dampener that must be tensioned correctly for it to work properly. I suspect that the shimmy problems many have are caused by the dampner not being tensioned properly. I haven't had any shimmy problems since I've been tensioning the king pin nut properly. Also, the service letter identifies the proper adjustment of the steering chains -- neither tension or slack.
Gene Feher
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Bruce Fenstermacher
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by Bruce Fenstermacher »

TerriM wrote:Hi Bruce,

Your reply relates to the steering arm assembly. Although my question was about the pawl, I do appreciate your suggestion. Last week, I noticed that the angle of the pull chain is not ideal as it pulls upwards. To improve responsiveness of my tw, I plan to order the steering assembly with the bent up arms. Good to know you recommend it! This give me more hope that it will be helpful!

Thank you!
Terri
Terri, you read more into my rambling than I intended.

Let me try to ramble a bit differently. While it is clear there is a improved angle of the pull on the control chain when the bent up steering arm is used, I do not recall reports from those that have the bent up control arm, to the effect there is much improvement. Perhaps because while the angle of the chain is improved, there is now a twisting action on the control horn greater than before.

Short and sweet version, if the bent up control horn improved control on a 170 really well, we'd all have them, and we do not.

On the other side I've never heard the bent up version hurt anything.

Personally the bent up version reminds me of twin rudders on a Aerocoupe, and so aesthetically I prefer the flat control arm. But that is just my quirk.

As for your real question about a short paw, like others, i did not know there where two different lengths. I'd question why you would want anything that would release the tail wheel earlier but there could be. And for ABI to bring it to the market, probably is a good reason for some application.
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GAHorn
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by GAHorn »

Terri, if you change your steering arms.... be advised you will also have to change the dust-cover to match it.

Personally, I'd stay with the original set-up in both steering arms and pawl.

There seems to be an often-asked query by new owners of these airplanes about how to improve tailwheel steering, as if they believe somehow that tailwheels should steer as effectively as nose-wheels. (I suspect these are mostly Piper trike-drivers who expect positive steering.)

There simply ain't no such thing! These tailwheels are not steering wheels.... they are "steerble" wheels.... as in, they can be "encouraged". Judicious use of differential braking is an important part of the process. I've flown both types of tailwheels and can tell no difference in effectiveness of the steering arms. I believe the up-turned steering arms were initially offered to L-19s as a later effort to increase strength to the arms. The Army pilots were pretty hard on them landing on rough strips and bent the "flat" arms so often. (The "flat" arms were made of softer metal and the upturned were made of steel.)

Your overhaul of your tailwheel will alone improve matters such that you'll likely believe you've discovered a huge improvement to whatever changes you introduce... until you become disenchanted again with the lack of positive steering. Again, I'd recommend you keep it original.

Next thing I'll do is ripe with opportunity to critique: Because the Bushwheel folks have become the mfr'r and go-to folks for Scott tailwheel support.... it is easily believed they know all about them. But if you see their You Tube video on how to adjust a tailwheel... after you become convinced they must know... you'll eventually realize they are just plain ignorant. Their video has one make the adjustments with the tailwheel lifted off the ground. I suppose that's because they must think that's when we use tailwheel-steering... while we're airborne. :roll:
Their assembly instructions are correct...but their adjustment for steering, pawl-engagement, and shimmy control is not. Nor is it correct to believe that the tailwheel "descends" after liftoff thereby tightening the steering chains.
The steering chains follow an ARC when the tailwheel is relieved of weight and do not need additional consideration for length due to flight vs ground ops. ( as long as original setups as directed by the original Scott instructs are followed. (When folks think they can improve the tailwheel by making modifications to steering arms and chains and attachment hardware choices.... they also often affect the original "arc" which they've now upset....thereby often being the creators of the very problems of which they complain.

Terri.... Are you presently suffering from tailwheel mis-behavior? If not...don't "fix" what ain't broken.

If so... then tell us what problem you are experiencing and post a picture of your setup.

Hope this helps.
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bagarre
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by bagarre »

On the steering arm types:
I switched to the upturned version after about 200 hours in the 170 when I rebuilt the tailwheel. You do need new upper and lower dust caps.

I made the swap that evening and was flying the next day - could not tell any difference at all.

The reason I rebuilt the tailwheel is because I swung the plane around too quickly, snagged a chain under the spring (chain guard on lower shackle is very important) and bent the right arm up nearly 90 degrees.

With the right arm bent 90 degrees, I had a little more trouble taxiing than usual but attributed it to the wind. I didn't even know it was bent until we got home that evening. When I tied her down that I saw it was bent.

Short arm vs long arm = no noticeable difference.
Short arm vs no arm = minor noticeable difference.

It wasnt until a few years later when I flew a Decathlon and an RV8 that I realized why people comment about the 170 lack of steering. Those two airplanes feel like the tail is bolted to the ground compared to the 170.

The 170's tailwheel isn't steerable as much as it's sprung to help it follow along. It's all in the rudder and brakes.
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edbooth
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by edbooth »

Wow, the 170 tail wheel is steerable?? I just thought it was there to hold the rear of the fuselage off the ground. :? :)
Ed Booth, 170-B and RV-7 Driver
Dooley
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Re: Long Pawl vs Short Pawl on ABW 3200 TW

Post by Dooley »

I tried the short arms and they were not sturdy enough. Somehow my 170 has a L-19 Rudder horn that provides a little more leverage and it was too much for the short tailwheel arms. The bent up arms
have a lot more material and can take more torque. Either way the airplane really depends on brakes, it steers poorly.
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