Wannabe:
What is the issue with this STC?

RGilland wrote:.... The mechanic told me the hole in the main gear for the stud on the axle is too tight of a tolerance to add the alignment shims. He is suggesting we get approval from the FAA and cut off the stud, or replace the axles with Cessna axles.....

I take it the inboard stud is incorporated into the axle? If it was me, and the inboard stud was preventing shimming the MLG wheels into alignment, I'd replace the axles with a set of HD steel standard axles, available from Spruce and others.

Hotrod180:
That is what the mechanic is recommending. I found a set of Cessna 182 axles. I am assuming the mounting bolt pattern is the same on the 170, 172, 180, 182. I was told the shims are the same for the different models so the pattern should be the same.

Here is what I have. It is the SA296GL STC. It is a Ralph Bolen Inc conversion with the parts serial number of TD000001 with the 337 being date 5/4/1979. The aircraft's owner at the time of the conversion was Ralph Bolen and was proir to the Williams in KS purchasing the STC.

Now my question is..... Should i still be concerned about this conversion?

As mentioned previously, I'm very certain that a good DER or DAR will be able to straighten out the paperwork part of the mess, figuring out which STC allows which gear, and which axle, etc.

Mechanically, in order to replace the original Bolen "axle" (that goes through a hole in the gear leg) with a standard Cessna style 4 bolt axle, you should really check with a DER to make sure that all the stresses and impact loads are properly addressed in this configuration. The "edge distance" between the bolt hole and the large axle hole is the big concern that someone needs to address.

IMHO, that is the only thing that should be keeping you up at night.

RGilland wrote:.....Now my question is..... Should i still be concerned about this conversion?

I think you're fine. I believe what Wanabe might be trying to point out is that Bob Williams (of Bush/Avcon fame) holds the STC now, and that many people have found him to be...let's just say problematic.

Personally, I would buy a set of steel axles, as sold by Spruce, McFarlane, etc. Not sure but they might all be manufactured by Airforms Inc. About $400 a side-- or splurge on titanium @ $1295 each.
Here's a link:

http://www.aircraftspruce.com/catalog/l ... aaxle1.php

All this thread tells me is that my IA was correct when one day, he was repairing a Tri-Pacer that had been converted to a Pacer. I asked what he was doing, and he said to me, "If you want a tail dragger, buy a tail dragger. If you want a tricycle, buy a tricycle. But don't buy a tricycle that has been converted to a tail dragger--it's nothing but trouble." At that same time, he was regularly servicing a 172 tail dragger conversion, which the owner had put lots of money into, with a new panel and interior, Powerflow exhaust, etc., etc. I said, "what about that fancy 172 tail dragger I've seen in your shop?" "Same thing."

Cary

I have been around a number of these conversions and they were a good conversion for the money if done right. They use the original 172/175 hollow aluminum axle which were subject to breakage ( see 170 Faa service difficulty reports from a number of years ago ) this steel stud through the axle puts compression on the axle thus for all practical purposes eliminating axle breakage. The hole through the gear doesn't create a stress riser or cause breakage in this area. Flexing is required for metal to fatigue and break, the axle and four bolts don't allow flexing anywhere between the four bolts, if it is going to break it will be through the upper bolt holes same as on any gear of this type. You already have a lot of shims, before you do anything make sure you have a alignment problem, then follow the cessna 180 instructions removing a small amount material from the hole won't weaken anything. Don't try to modify something that is well designed. I know a cattle feed salesman who has put over 3000 hours on a 175 with this set up landing in the most god awful rough fields with the worst problems being broken tail wheel springs. Another ground looping his with enough force to scrape a wing and his body weight breaking a door hinge, damage was limited to broken out board gear support which still held the plane up and he taxied to the hanger.

Cary wrote:... he said to me, "If you want a tail dragger, buy a tail dragger. If you want a tricycle, buy a tricycle. But don't buy a tricycle that has been converted to a tail dragger--it's nothing but trouble." ...

I have to both agree and disagree. IMHO a conversion is a lot of time and/or money to do, you're usually better off buying one already done that someone else has invested that time and money into.

That said, the conversions are only as good as the people doing the work. A friend of mine converted a PA22 to a taildragger (aka 22/20) about 20 years ago. It tracked straight as a string and handled like a dream. He and a buddy put a lot of time into measuring and re-measuring everything before they did any welding, and it showed. I myself bought an already converted C150TD back in 2008, and again- it handled great. Just as good if not better than the C170 I owned before that.

Leaf spring Cessnas are great because you can shim the axles to correct all but the most drastic alignment issues. The axle is incorporated into the gear leg on a Pacer, and if misaligned you must correct by bending. Possible but a hassle, and very possible to over-correct and/or otherwise make it worse. Tubular gear Cessna s are about impossible to correct-- like a Pacer, the axle is part of the gear leg, but unlike a Pacer it's spring steel which is just about impossible to bend into submission.

bush master wrote:I have been around a number of these conversions and they were a good conversion for the money if done right. They use the original 172/175 hollow aluminum axle which were subject to breakage ( see 170 Faa service difficulty reports from a number of years ago ) this steel stud through the axle puts compression on the axle thus for all practical purposes eliminating axle breakage. ....

So the reasoning behind the stud was to prevent breaking the hollow aluminum axle? I don't know how long they've been available, but it seems like a better idea would have been to use a solid aluminum "ski axle" or better yet a steel axle.

RG
First read my two apologies on page one.
The STC for sale of original Bolen to Avcon is/seems OK Key #s are 296

When I first opened the link that come up the first thing I saw was 172.
My brain quit on me before I put the letter "K" on the end, (as in C172K etc.) followed by a list of C175s. STC - SA383GL

Your concern should be with the repair work, and any replacement gear.

See copied mssg.

March 1, 2007
“A couple of weeks ago someone actually answered when I called Avcon.
I was asking about approved skis for the conversion, but we ended up talking quite a bit about the "Bolen gear".
Bob said, “There are two versions of the Bolen gear legs.” The earlier ones were shorter than the later ones. (Circa 1990, I think). The new legs are "similar to 180 gear" which he thought should bring the height to within "1 to 1 1/2 inches" of a 180. I know that wasn't your question, but thought it was interesting.”

It would have helped to have all the information in the first post. The secondary post with additional damage listed brings up a whole new batch of issues.

Wishing ya better luck than you have had so far with this plane.

CC

Thanks for all the replies. I have decided to start from scratch on the alignment. I removed all the shims and sat the plane down on grease plates and took some measurements. I've got 10 deg of positive camber on both sides and nearly 1.28 inches of toe in. This seems a little excessive, to my untrained eye, to have just had the gear reworked.

Also, does anyone know if to can mic the old shims and figure out which part number they are. The numbers are gone off the backs of them and id like to reuse some of them if possible.

Resurrecting an older thread....
I saw a C175 today which had been converted to tailwheel gear via the Bolen STC.
Got to wondering about the extra bolt through the gear leg, when I remembered this had been discussed here a while back.
Read this thread, saw comments about selecting shims, then googled up this Aircraft Spruce webpage.
http://www.aircraftspruce.com/catalog/l ... eShims.php
If you click the "selection guide" button, you get a neat little explanation which shims to use based on how far out of alignment your wheels are. Unfortunately these shims apparently only correct for toe-in, not camber.