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Re: Europa-List: cowl cutting - bak edge

Subject: Re: Europa-List: cowl cutting - bak edge
From: Bud Yerly <budyerly@msn.com>
Date: Sun, 6 Mar 2011 19:37:29
If you didn't need washers, you installed the mount perfectly.
As for the cut of the rear, you bet it is not uncommon to cut the right 
side more than the other.
For offset, I just do the angle of 1 1/16 inch at 20 inches to make the 
angle and it is remarkably close.
The cowl actually has a bit of P factor lean on the forward flange. 

Before you cut, be sure to have the exhaust fitted and your propeller 
flange mounted as you may find it necessary to push the cowl forward a 
bit for more clearance and or to get that look just right.  Also the 
exhaust often needs a bit of adjustment left or right/fore or aft to get 
the clearance just right.
As for the cowl:
As you cut, the cowl drops down into the rebate and changes everything 
during the fitting.  To get it just right, I put two inch tape on the 
fuselage rebate line.  Now I have a line that is exactly 2 inches longer 
than the cowl line.  If I push the cowl to the spinner, I then scribe my 
cowl using the end of the tape by using a compass and pen.  OK, I know 
the cowl is now 1/8 too long as is up against the spinner backplate.  A 
spinner back plate to cowl clearance of 1/8 inch looks very nice.  So 
all you have to do is cut another 1/8 inch off.  Occasionally, there is 
a difference from the top to the bottom with the sides fine.  Filler 
works.  Then put a 2 oz. cloth over the filler so it won't crack and 
flick off.  That is a heck of a surprise in flight. 
Some use a technique to leave the spinner a bit high at first as the 
engine settles believe it or not.  I use 1/16 inch on initial fit if it 
has been a while, then re-level the engine again before final drill of 
the cowl.

When the cowl is fitted on the floor for smooth sides, it will 
occasionally pucker on one or both sides between your clecos when 
installed on the plane (I start with 3/32 inch then go up in 
increments).  Gravity works 24/7 and you will note that the sag in the 
cowl due to gravity will pull the nose down a bit and this causes 
puckers in the side.  Once the cowl fits inside the rebate, I work the 
cowl sides to tart from the front and push the most forward pucker in 
and re-drill the cleco hole and go aft to the next pucker.  It cuts down 
on filler....   

Best regards.

Bud Yerly
  ----- Original Message ----- 
  From: graeme bird<mailto:graeme@gdbmk.co.uk> 
  To: europa-list@matronics.com<mailto:europa-list@matronics.com> 
  Sent: Sunday, March 06, 2011 3:39 PM
  Subject: Europa-List: cowl cutting - bak edge


<graeme@gdbmk.co.uk<mailto:graeme@gdbmk.co.uk>>

  before I cut the back edge of the XS cowl for a 912S I'd like to check 
that its normal to take about 2mm off the port side and 12 mm off the 
starboard. I realise the engine is 1.5 off to starboard but I dont know 
if the cowl design caters for this already. My engine didnt need any 
adjustment washers and I measured the angle at 1.57 deg.


  Thanks

  --------
  Graeme Bird
  G-UMPY
  Mono Classic/XS FWFD 912ULS/Warp drive FP
  Build nearing completion


  Read this topic online here:


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