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Make your own two piece nosebowl??

Posted By:
Donald Morrisey
Homebuilder or Craftsman
#1 Posted: 1/27/2010 12:01:41

I want to have a two piece nosebowl for my homebuilt w/ Lyc O-235 L2C.  I already have a standard Lyc nosebowl from ACS: http://www.aircraftspruce.com/catalog/appages/mc3a.php

The two piece nosebowl That ACS offers is very expensive and doesn't work for my application as it is set up for a 14" spinner and my spinner is 10" and that's what I need for my Sensenich 2EK composite ground adjustable prop.  I would like to make a two piece nosebowl out of my one piece.  It's easy enough to cut it across the middle of the air inlets.  What would be missing is the "flange' that the other half must attach to.

To create this flange I am thinking I could add a fiberglass flange...or rivet on strips of aluminum, maybe .040 to accomplish the same thing.  One of my concens about adding the fiberglass is that the flange wouldn't be an integral part of the existing fiberglass bowl and would essentially be a patch that is glassed in.  I'm thinking aluminum might be stronger, either riveted in or attached with 8/32 nuts and bolts with a decent size washer on the the fiberglass side.

The actual areas that have to be flanged are not big, there are four locations across the air inlets, the biggest being 4 or 5" wide.

Has anyone made their own and if so how and how has it held up? 

Any thoughts or comments on which of my methods might be better/stronger?

Or...a source for a two piece nosebowl that would work with an O-235 with a 10" spinner.




N2C; BushCaddy R 120 w/O235-L2C; http://www.donsbushcaddy.com
Joanne Palmer
Young Eagles Pilot or VolunteerHomebuilder or Craftsman
#2 Posted: 1/28/2010 09:31:42

Add the flange as a fiberglass "layup".


First I would find a locall EAA builder who's building a composite airplane for guidance on how to bond.  Failing that attend a Sportair Workshop on Composite construction. 

I would add the flange(s) and would overlap the nosebowl structure at the split line by 1 inch or as much as an adjacent cutout will allow.  you'll need 5 or 6 plies and you'll need to use Bi-directional (BID) glass.  You should also orient the plies as 45 90 (45) 45 90 45 to give it adequate strength and stiffness.  One side (i'd chose the lower, but it doesn' t matter) should be a "release" side and you can do that by covering the area wher the glass is to mate with vinyl tape (electricians tape) and then covering that with any wax.  Apply good bonding techniques to the other side and then layup the glass/epoxy wetouts.  The apply peelply to absorb the excess epoxy then weigh everything down with plastic bags filled with water. This will allow the glass to conform to the nosebowl surfaces.  When set remove the peel ply and clean up the edges with sandpaper. 


Add your fasteners (I'd use AN525 screws with K1000 nutplates, but that's just me) and fit to your remaining cowl.

Good luck with your project. 

Kenneth Dick
Homebuilder or Craftsman
#3 Posted: 1/28/2010 21:09:46

Bill Havener, 1409 6th Avenue, Sterling, Ill. 61081, phone 815.626.0910 has successfully (owning Form 337) fabricated a split nose cowl and nosewheel fairing for a short wing Piper , and can provide detailed descriptions on how the work was done. You may find the information useful for your project.

Neil Sidders
Homebuilder or Craftsman
#4 Posted: 1/29/2010 10:15:16

I recently split the nose bowl on my Acro Sport which has the same nose bowl you have.

The first step is to sand the inside in the area you want the seam to be.  Lay out your cut line on the outside and prepare to make the cut.  Using a very thin saw or cutoff wheel make a stitch cut on the line.  By that I mean make cuts about 3  to 5 inches long leaving about 3/8" between the cuts.  Use a release tape of some type on the inside where you want the flange. I release taped the top half.  It is your choice.  Not knowing what resin was used to make the bowl, I used epoxy.  It will bond to the others but it won't work well the other way around.  For release tape I used the thin aluminum foil tape that is used in duct work.  Wax the tape generously and wipe the area to be bonded with acetone.  I used a 5 layer sandwich lay-up.  You can do a wet layup right in the bowl but if you know how to do the sandwich it is much neater.  You need at least an inch on either side of the cut line. I made the sandwich 2 1/2"wide and it worked great.  After it is cured, lay out the screw holes and drill through, then carefully cut the stitches that were holding the bowl together.  It will then pop apart and you can trim up and install nut plates.  The gap left by the cut is about right for paint  and the bowl is exactly the same shape as before.

Donald Morrisey
Homebuilder or Craftsman
#5 Posted: 1/29/2010 16:33:14 Modified: 1/29/2010 16:37:31

Great ideas,

I'll use the Bi Directional fiberglass and alternating pattern.  I do know how to make the 5 layer sandwich and the idea of the stitch cut is excellent.  Also the idea of the water bags to weight it down.  Should be easy enough to do.



N2C; BushCaddy R 120 w/O235-L2C; http://www.donsbushcaddy.com