Repairing Fiberglass Wheel Pants, Part II

[Jay Honeck]

I stopped by the shop this morning, to see how the wheel pants were
coming along.

What a difference! All of the wowed-out holes have been backed with
aluminum that has been riveted to the old fiberglass, and then
fiberglassed and filled over and around. High stress areas have been
reinforced, and really high stress patched areas have been filled with
"JB Weld" -- a virtually indestructable epoxy.

Best of all, the old attachment system has been completely upgraded.
The stupid "dzu" connector system (that held the two clamshell halves
together)has been eliminated, in favor of self-locking screws that
won't vibrate loose. This has meant filling in all the large dzu-sized
holes and re-drilling them smaller, but I'm hopeful that the danged
things actually won't "wow" out and come disconnected due to vibration
anymore.

Also, the dumb attachment bolts (that threaded into the struts
themselves) have been eliminated. Instead, my A&P is tapping bolts
into the *struts*, so that they stick out through the holes in the
pants. This allows the use of self-locking nuts and cotter pins -- a
much more secure attachment method -- and should eliminate the problem
of those bolts vibrating loose (we've actually lost two of them in the
last several years!)every few flights.

As usual, I'm impressed with what he's doing. Best of all, because
he's only going to have to paint one color (he thought he was going to
have to paint all four colors, at first), the cost is going to come in
way under estimate.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Bruce Cunningham]

(Jay Honeck) wrote in message >...
> I stopped by the shop this morning, to see how the wheel pants were
> coming along.
>
> What a difference! All of the wowed-out holes have been backed with
> aluminum that has been riveted to the old fiberglass, and then
> fiberglassed and filled over and around. High stress areas have been
> reinforced, and really high stress patched areas have been filled with
> "JB Weld" -- a virtually indestructable epoxy.
>
> Best of all, the old attachment system has been completely upgraded.
> The stupid "dzu" connector system (that held the two clamshell halves
> together)has been eliminated, in favor of self-locking screws that
> won't vibrate loose. This has meant filling in all the large dzu-sized
> holes and re-drilling them smaller, but I'm hopeful that the danged
> things actually won't "wow" out and come disconnected due to vibration
> anymore.
>
> Also, the dumb attachment bolts (that threaded into the struts
> themselves) have been eliminated. Instead, my A&P is tapping bolts
> into the *struts*, so that they stick out through the holes in the
> pants. This allows the use of self-locking nuts and cotter pins -- a
> much more secure attachment method -- and should eliminate the problem
> of those bolts vibrating loose (we've actually lost two of them in the
> last several years!)every few flights.
>
> As usual, I'm impressed with what he's doing. Best of all, because
> he's only going to have to paint one color (he thought he was going to
> have to paint all four colors, at first), the cost is going to come in
> way under estimate.


Sounds like you'll be airborne pronto! Glad it is going so well.
You're doing it right from you're desription. I have used JB weld in
several places for cowling and wheel strut fairing repairs. It is
thick and stays where you put it. One thing I'd like to mention that
you might consider; Southco, Camlock, and Dzus fasteners are spring
loaded cushioned type attachments that give a little under load and
are good for high vibration locations like cowlings, etc. A solid or
hard mount can accelerate cracking if not done perfectly. The original
Dzus may not have been installed correctly which is why they have torn
out.

Regards,
Bruce Cunningham

[Jay Honeck]

> thick and stays where you put it. One thing I'd like to mention that
> you might consider; Southco, Camlock, and Dzus fasteners are spring
> loaded cushioned type attachments that give a little under load and
> are good for high vibration locations like cowlings, etc. A solid or
> hard mount can accelerate cracking if not done perfectly. The original
> Dzus may not have been installed correctly which is why they have torn
> out.

Yeah, after I posted I started wondering about that. Once everything is
locked in more firmly in place on those wheel pants, only the fiberglass
will be able to flex -- which is probably not a good thing.

I guess we'll have to watch 'em, and really work on our greasers...

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Jay Masino]

Jay Honeck > wrote:
> Yeah, after I posted I started wondering about that. Once everything is
> locked in more firmly in place on those wheel pants, only the fiberglass
> will be able to flex -- which is probably not a good thing.
>
> I guess we'll have to watch 'em, and really work on our greasers...
>

I wonder if changing the fasteners and adding the aluminum "backing"
material effectively invalidates the original Laminar Flow Fancy Pants STC
and the 337 that was originally filed on your plane. I think I still
would have called Laminar Flow and asked them what their recommended
repair procedure is, just in case.

--- Jay



--
__!__
Jay and Teresa Masino ___(_)___
http://www2.ari.net/jmasino ! ! !
http://www.oceancityairport.com
http://www.oc-adolfos.com

[Michael]

"Jay Honeck" > wrote
> Yeah, after I posted I started wondering about that. Once everything is
> locked in more firmly in place on those wheel pants, only the fiberglass
> will be able to flex -- which is probably not a good thing.

I am very much not a fan of allowing a garden-variety A&P (regardless
of years of experience) modify an aircraft at will. Modification
should be approached cautiously, especially when you are modifying
something designed by degreed engineers with years of experience, and
your education is of the vo-tech variety. No amount of field
experience as a mechanic makes you an engineer.

I used to belong to a club that had an aircraft with a rubber doughnut
(sort of like the Mooney gear but not quite) in the tailwheel
assembly. It was a definite weak point - sometimes it would not last
out the season. And it really wasn't seriously structural - it hardly
carried any weight. So this A&P/IA, a real greybeard with decades of
experience and a reputation that brought owners of expensive aircraft
to his nondescript shop from hundreds of miles away, "fixed" the
problem by adding an Aluminum bracket.

It was great for about three years. Then we noticed that the many
minor shocks that were absorbed by (and which eventually destroyed)
the rubber doughnut were now being transmitted to the tail assembly -
which started to crack. It had to be rebuilt at great effort and
expense by another greybeard - who restored everything to factory
design and told us to leave well enough alone.

The FAA codifies this in regulations that govern how alterations are
to be performed. Of course in typical FAA fashion this doesn't make
anything safer - just more expensive - but while the solution is
incompetent, the problem is very real.

Michael

[Jay Honeck]

> > Yeah, after I posted I started wondering about that. Once everything is
> > locked in more firmly in place on those wheel pants, only the fiberglass
> > will be able to flex -- which is probably not a good thing.
>
> I am very much not a fan of allowing a garden-variety A&P (regardless
> of years of experience) modify an aircraft at will. Modification
> should be approached cautiously, especially when you are modifying
> something designed by degreed engineers with years of experience, and
> your education is of the vo-tech variety. No amount of field
> experience as a mechanic makes you an engineer.

Wheel pants are not structural -- although you wouldn't know it by their
cost. There is nothing in the FARs barring an A&P/IA from making field
repairs to non-structural parts. (Or even owners, AFAIK.)

Which is different, I know, from being SMART to do it -- but Jay M. was
questioning the legality of it all.

Incidentally, this is our first experience flying the 235 without wheel
pants. We trued out at about 135 knots on the way to Wisconsin yesterday,
in absolutely calm air. Since we normally true out around 142, the fancy
pants apparently net us 5 to 7 knots.

Which is almost exactly what the previous owner told us they got him, so I
guess the danged things actually work.

It's still a mystery to me how those huge wheel pants (MUCH bigger than
Piper stock) can be more aerodynamic than the simple (and much smaller)
round tire hanging in the slipstream -- but I can't argue with results!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Jay Masino]

Jay Honeck > wrote:
> Which is different, I know, from being SMART to do it -- but Jay M. was
> questioning the legality of it all.

I guess the issue I was trying to raise was NOT who did it, but rather how
it's done. I was obviously in favor of you doing it yourself. I know
that every speed mod that I've put on my plane came with a supplement that
describes maintenance and upkeep of the mod, so it only seemed prudent
that you asked Laminar Flow how THEY think the repair should be done.
Since the Fancy Pants are not the OEM wheel pants, and are installed under
an STC, it would seem that modifying them are "not quite" the same as
repairing standard OEM wheel pants.

--- Jay



--
__!__
Jay and Teresa Masino ___(_)___
http://www2.ari.net/jmasino ! ! !
http://www.oceancityairport.com
http://www.oc-adolfos.com

[Michael]

"Jay Honeck" > wrote
> Wheel pants are not structural -- although you wouldn't know it by their
> cost. There is nothing in the FARs barring an A&P/IA from making field
> repairs to non-structural parts. (Or even owners, AFAIK.)
>
> Which is different, I know, from being SMART to do it -- but Jay M. was
> questioning the legality of it all.

I'm not questioning the legality of this at all.

There is nothing in the FAR's barring an A&P/IA making field repairs
to sructural parts, either. He is also permitted to make MINOR
alterations on a logbook entry, using acceptable methods and
practices. MAJOR alterations require approved data. Who decides what
is major? Well, in the end the A&P/IA.

So your A&P made a minor mod. What's more, I AGREE that the mod is
minor. It will NOT cause your plane to fall out of the sky. What it
may (and I think will) eventually do is destroy a good pair of wheel
pants.

Michael

[Jay Honeck]

> So your A&P made a minor mod. What's more, I AGREE that the mod is
> minor. It will NOT cause your plane to fall out of the sky. What it
> may (and I think will) eventually do is destroy a good pair of wheel
> pants.

Well, they were junk before this repair started (or, at least, unusable) --
so they could only go up from there!

I'll talk to my A&P. If I know him, he's already thought this thing
through.

(He's an old EAA-er, and winner of the Antique Aircraft Association's
coveted "Grand Champion" trophy -- so he's not just another wrench...)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[G.R. Patterson III]

Jay Honeck wrote:
>
> Incidentally, this is our first experience flying the 235 without wheel
> pants. We trued out at about 135 knots on the way to Wisconsin yesterday,
> in absolutely calm air. Since we normally true out around 142, the fancy
> pants apparently net us 5 to 7 knots.

Anyone know how much improvement the stock pants yield?

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Aaron Coolidge]

G.R. Patterson III > wrote:
: Jay Honeck wrote:
:>
:> Incidentally, this is our first experience flying the 235 without wheel
:> pants. We trued out at about 135 knots on the way to Wisconsin yesterday,
:> in absolutely calm air. Since we normally true out around 142, the fancy
:> pants apparently net us 5 to 7 knots.

: Anyone know how much improvement the stock pants yield?

George, on my 180 I was hoping for a 1 to 2 knot improvement by going from
naked wheels to the stock wheel pants. I got nothing. Zero speed increase.
But, the wheel pants nicely match the paint scheme, and they do keep the sun
off of the tires, so there is some value to them.
If I could get 5 to 7 knots out of the wheel pants that Jay has, I would
strongly consider them - sounds like I could.
--
Aaron Coolidge (N9376J)

[Dave Butler]

G.R. Patterson III wrote:
>
> Jay Honeck wrote:
>
>>Incidentally, this is our first experience flying the 235 without wheel
>>pants. We trued out at about 135 knots on the way to Wisconsin yesterday,
>>in absolutely calm air. Since we normally true out around 142, the fancy
>>pants apparently net us 5 to 7 knots.
>
>
> Anyone know how much improvement the stock pants yield?

Don't know about Jay's, but some of the Piper POHs have a note on the
performance charts about how to adjust the speeds if the stock fairings are removed.

[zatatime]

On Tue, 28 Sep 2004 14:15:27 GMT, "G.R. Patterson III"
> wrote:

>
>
>Jay Honeck wrote:
>>
>> Incidentally, this is our first experience flying the 235 without wheel
>> pants. We trued out at about 135 knots on the way to Wisconsin yesterday,
>> in absolutely calm air. Since we normally true out around 142, the fancy
>> pants apparently net us 5 to 7 knots.
>
>Anyone know how much improvement the stock pants yield?
>
>George Patterson
> If a man gets into a fight 3,000 miles away from home, he *had* to have
> been looking for it.

I've flown my 235 without pants for an extended period of time. When
I put them back on I got about a 2-3 mph increase (about 2kts). So it
sounds like the fancy pants add about 5 more to cruise.

HTH.
z

[Jay Honeck]

> Anyone know how much improvement the stock pants yield?

I know on our Warrior, the stock wheel pants made a very small, almost
indiscernible difference.

BTW: I got the "new" wheel pants back from the shop yesterday, and
reinstalled them -- wow, what a difference.

All of the self-locking fasteners actually work. The bolt attachments to the
landing gear now have self-locking nuts, with cotter pins. Everything is
tight, clean, and functional.

We had a long discussion about the potential need for allowing "flex" in the
wheel pants, which, it turned out, is something my A&P knows something
about. It seems he has made (from scratch) quite a few wheel pants, for
various aircraft, over the last 35 years, and his findings are that the most
rigid, strongest possible mounting brackets make the best, longest lasting
wheel pant system.

To illustrate this, he showed me a plane on the ramp, with "normal" stock
wheel pants. We found that there is absolutely no wheel pant movement when
wiggled.

Later, I found an Archer with the modern-day Piper equivalent of my "fancy
pants," and they, too, are mounted as stoutly as a bridge truss. There is
absolutely no movement at all when you try to shake them. (Yes, the owner
was there!)

My A&P's opinion is that the old cam-lock connectors, when new, were also as
tight as a drum. The "flex" we noticed was simply the result of wear and
tear -- it was not by design.

The only downside of the new system: It takes FOREVER to install the danged
things. (Which, of course, was the idea behind the quick-release cam-lock
connectors in the first place...)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[dave]

On my citabria, the only improvement, and it's a good one, is they keep
the mud from flying up on to the bottom of the wing and fuseloge. I
didn't put them back on this year because it's impossible to check the
tire pressure with them on.

Dave

G.R. Patterson III wrote:
>
> Jay Honeck wrote:
>
>>Incidentally, this is our first experience flying the 235 without wheel
>>pants. We trued out at about 135 knots on the way to Wisconsin yesterday,
>>in absolutely calm air. Since we normally true out around 142, the fancy
>>pants apparently net us 5 to 7 knots.
>
>
> Anyone know how much improvement the stock pants yield?
>
> George Patterson
> If a man gets into a fight 3,000 miles away from home, he *had* to have
> been looking for it.

[Jay Honeck]

> On my citabria, the only improvement, and it's a good one, is they keep
> the mud from flying up on to the bottom of the wing and fuseloge. I
> didn't put them back on this year because it's impossible to check the
> tire pressure with them on.

Not THAT is a serious design flaw!

Our Fancy Pants have little doors that open (secured with a phillips
screw) to allow access to the tire filler valve. Considering that
tubed tires routinely lose 25% of their pressure every few weeks, I
can't understand why anyone would manufacture a wheel pant without
such a door.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"