A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Home Built
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Archer Cowl needs work - Advice?



 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1  
Old February 16th 05, 10:52 AM
Bob Chilcoat
external usenet poster
 
Posts: n/a
Default Archer Cowl needs work - Advice?

We have a '74 PA-28-180 - the first year this model was called an "Archer".
The cowl is not in the greatest shape, partly because of its age, and partly
because one of the partners a few years ago landed on a runway that was
about 18" too short and slid gently into the chain link fence at the end
:-( Engine has had all the AD required inspections, etc, but the cowl did
get a few bruises. We're into our annual as of yesterday and we have two
problems that need to be dealt with ASAP.

The first is that there is a slot in the back of the bottom cowl were it
slides over the nosewheel strut. To keep the two halves of this slot from
flapping around aafter it's installed, a (roughly 12- 15" long) aluminum
"bridge" is screwed across the gap after the cowl is put in place, held in
place by four screws and large trim washers that go through the fiberglass
of the cowl and into the aluminum bridge. Two of these screws, at the outer
ends of the bridge, are fine. The two nearest the slot, however, have been
pulled away from the fiberglass, and now have nothing to go through. The
corners of the fiberglass that they used to go through are simply gone.
Someone at some point riveted a strip of aluminum to the back edge of the
fiberglass, and the screws now go through this, but the aluminum strips are
bent and the cowl no longer fits flush. We really need to remove the cludgy
aluminum strips and redo the fiberglass so that the cowl fits better.

Of course one problem is that this area is very oily from years of Lycoming
Leakage (LL). My first question is, what is the best solvent to remove the
oil so that a repair has a chance of adhering? I plan on cleaning
everything and then thinning the glass a bit roughly 1.5 inches back from
the edge, and then feathering and building up the area with glass cloth and
epoxy to remake the back edge of the cowl (I've done a lot of boat building
and repair, so this isn't rocket science to me, although I've always worked
with polyester resins before). Next questions are, what is the best
fiberglass for this? mat or cloth? S-glass, E-glass or something else?
What epoxy is the best for repairs? Is there a kit available somewhere with
everything (glass and epoxy) I need? If I want these quickly, what source
should I use? I've seen complaints about Aircraft Spruce. Would Wicks be
better for fast turnaround? Someone else?

The other problem with the cowl is that there has been some delamination
near the top of the low cowl where the propeller shaft opening is formed.
This area has a lot of curvature, and there is a foam or balsa wood
reinforcement bow epoxied into this area behind the curved opening. The
cowl molding has pulled away slightly from this reinforcement bow. Not very
much, but the A&P thinks that this should be closed up before the
delamination propogates further. This is a more difficult problem, because
there is very little clearance to get anything into the gap, there doesn't
seem to be an edge to overlay a patch onto, and of course I have no idea how
much oil has drifted in there that would prevent adhesion.

My current plan here is to wash it out with some solvent to get most of any
oil film out of there, and then inject a thin epoxy as deeply as possible
into the crack with a syringe. Questions here are mostly about what solvent
won't dissolve the reinforcing bow if it's a foam and not balsa wood, and
where can I get a really thin, watery epoxy. Also, does anyone have any
other ideas about fixing this area?

Of course, we'd like to get this all done before the annual is done, so that
the plane doesn't have to sit outside without a cowl. The last question is,
is there someplace someone can recommend that we could have this done? I
really don't have the time to do this, but will make the time in order to
get it done right if necessary. I've thought of calling bodyshops that
specialize in Corvettes, and boatyards, but they don't usually deal with
weight issues. I can just see a quarter inch of heavy polyester and glass
roving added to the inside of the cowl. I'd rather not have to log a major
CG change.

Anyway, any and all suggestions and advice would be greatly appreciated. I
woke up early this morning thinking about this. Maybe I can go back to
sleep now. Thanks, guys.

--
Bob (Chief Pilot, White Knuckle Airways)



 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Homebuilt Aircraft Frequently Asked Questions (FAQ) Ron Wanttaja Home Built 1 January 2nd 04 09:02 PM
Homebuilt Aircraft Frequently Asked Questions (FAQ) Ron Wanttaja Home Built 0 October 2nd 03 03:07 AM
Ford V-6 engine work Corky Scott Home Built 19 August 21st 03 12:04 PM
Homebuilt Aircraft Frequently Asked Questions (FAQ) Ron Wanttaja Home Built 4 August 7th 03 05:12 AM
Homebuilt Aircraft Frequently-Asked Questions (FAQ) Ron Wanttaja Home Built 0 July 4th 03 04:50 PM


All times are GMT +1. The time now is 04:54 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AviationBanter.
The comments are property of their posters.