VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 04-29-2018, 04:02 PM
Adam W Adam W is offline
 
Join Date: Feb 2016
Location: Thornhill, Ontario, Canada
Posts: 97
Default cowl install question

Thank you in advance to anyone who takes the time to reply here
after much research on the cowl install i dove in. filtering through all the recommended measurements for simulated spacers, the inconsistency between VANs manual and the FAQ on their site i determined I'm going with 2-1/8 spacer and 1/4" spacing between cowl and flange on spinner backplate.
Today i got to it, and with the ring gear on, the spacers in and backplate mounted the cowl just makes it to 1/4" space to spinner flange. there is literally nothing to cut off the aft side. This caused me to be concerned I have already gone wrong?
has anyone found the latest cowls require no aft side trimming. im only referring to the top cowl so far I have not fit the bottom yet
im using the Hartzel 2 blade BA constant Speed.
__________________
Adam Wachtel
Thornhill Ontario Canada
Building RV7 #70770
90% Done 90% To Go
Vans Airforce Dues Paid

Last edited by Adam W : 04-29-2018 at 04:07 PM.
Reply With Quote
  #2  
Old 04-29-2018, 08:59 PM
RV7 To Go RV7 To Go is offline
 
Join Date: May 2011
Location: Ontario, Canada
Posts: 110
Default Cowl

Can't speak to the latest cowls but I had about 2" to cut off the back of my cowls (2008 kit) with the standard extension. I would suggest no less than 3/8" clearance from the back of the spinner to the cowl. Any less and it becomes difficult to re and re the cowl. One of the guys who has built 8 or 9 RV's leaves 1/2" for this reason. I split the difference between Vans 1/4" and his 1/2" and did 3/8" which worked out ok. I had a 4 with a 3/16" gap and it was a pain getting the bottom cowl on and off. FWIW.
Al
Reply With Quote
  #3  
Old 04-29-2018, 09:20 PM
Bevan Bevan is offline
 
Join Date: Sep 2007
Location: BC
Posts: 1,563
Default

Adam,

I don't think you need/want a spacer with a Hartzell CS prop.

Which engine do you have?

Confirm you have 7 not 7A?

I have RV7A with 0-360 and Hartzell CS prop, no prop spacer. I cut a couple inches off the cowl for a 1/4" space between spinner and cowl. I don't have much trouble getting cowls on off by myself.

Bevan
__________________
RV7A Flying
O-360-A1F6 (parallel valve) 180HP
Dual P-mags
Precision F.I. with AP purge valve
Vinyl Wrapped Exterior
Grand Rapids EFIS
Located in western Canada

Last edited by Bevan : 04-29-2018 at 09:40 PM.
Reply With Quote
  #4  
Old 04-29-2018, 09:31 PM
rockwoodrv9 rockwoodrv9 is offline
 
Join Date: Dec 2011
Location: Meridian ID, Aspen CO
Posts: 2,456
Default

Adam, I had more to cut off that what you are talking about. I have a 9a with Catto and spacer, but O-320. Something doesn't sound correct. Can you post a picture or a link to one?

One thing to think about is on the horizontal cut, favor cutting more off the bottom that the top. You will have an easier time getting the cowl off. If you are a TD, then not as much problem, but still worth considering.
__________________
rockwoodrv9a
Meridian Idaho
rockwoodrv9a@gmail.com
O-320 D2A
Awaiting DAR Inspection
Reply With Quote
  #5  
Old 04-29-2018, 10:25 PM
Adam W Adam W is offline
 
Join Date: Feb 2016
Location: Thornhill, Ontario, Canada
Posts: 97
Default

it is a tail dragger, constant speed prop
imscratching my head now!
__________________
Adam Wachtel
Thornhill Ontario Canada
Building RV7 #70770
90% Done 90% To Go
Vans Airforce Dues Paid
Reply With Quote
  #6  
Old 04-30-2018, 08:34 AM
sahrens's Avatar
sahrens sahrens is offline
 
Join Date: Jan 2007
Location: Northern CA
Posts: 402
Default

Hi Adam,

By using the spacer are you fitting the cowling without your propeller installed? I did it that way on my 7, and to answer your question, I had to trim off about 1.5 to 2.0 inches. But that was a couple of years ago.

Here is how I worked through that process.

http://www.mykitlog.com/users/catego...category=11167

Scroll Down to the first entry and it briefly discusses the spacers.
__________________
Scott
RV-7 N818BG (flying)
Bearhawk Patrol (building)
Reply With Quote
  #7  
Old 04-30-2018, 08:50 AM
Mark H's Avatar
Mark H Mark H is offline
 
Join Date: Jul 2011
Location: Indianapolis, IN, USA
Posts: 55
Default

Adam,

I don't think you are alone in your experience. I set up my cowl with 2-1/8" temporary spacers between the starter ring and the spinner backplate, and it worked out just right for a 1/4" gap once everything was installed. I did not have a lot of excess to cut off. Looking at my construction photos before trimming the top cowl, it did not cover all the rivet holes around the firewall, so I'm guessing I trimmed less than 1/4" off the aft side of the top cowl in some areas. Just make sure with starter ring is seated properly, fit the spacers and spinner backplate, remeasure the prop to verify the spacing is correct, and go for it!
__________________
Mark Hansen
Indianapolis, IN
RV-7A N896PS
Flying
Reply With Quote
  #8  
Old 04-30-2018, 09:38 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,878
Default

Quote:
Originally Posted by Mark H View Post
Just make sure with starter ring is seated properly, fit the spacers and spinner backplate, remeasure the prop to verify the spacing is correct, and go for it!
And make sure the spinner bulkhead is flat on its face (check with a straight edge).

The forming process often leaves a dished shape in the center of the bulkhead which can position the perimeter flange further fwd than nominal.

The RV-14 spinner installation plans (AVAILABLE HERE) are a bit more comprehensive than for the other other kits. Page 44-02 describes checking the aft bulkhead for flatness and gives a nominal dimension between the ring gear and the aft edge of the rear bulkhead flange, that you can use for reference.
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #9  
Old 04-30-2018, 01:27 PM
Adam W Adam W is offline
 
Join Date: Feb 2016
Location: Thornhill, Ontario, Canada
Posts: 97
Default

thank you this has been reassuring and helpful

can anyone comment on the amount they lowered the top cowl to compensate for engine sag?
__________________
Adam Wachtel
Thornhill Ontario Canada
Building RV7 #70770
90% Done 90% To Go
Vans Airforce Dues Paid
Reply With Quote
  #10  
Old 06-29-2018, 09:05 AM
Wunderon's Avatar
Wunderon Wunderon is offline
 
Join Date: Jun 2014
Location: Seattle (Edmonds) and Iowa
Posts: 131
Default drilling top hinges

Somewhat related, when drilling the top hinges to the cowl, is it best to hold the ‘slack’ out of the hinge due to the .090 pin‘s sloppy fit, or let it ride in the ‘middle’ of the hinge eyes where it wants to?

Seems like the cowl would end up loose if you don’t hold the hinge separated, but that might make it hard to put on and remove.
__________________
Dave Grimmer
RV8 firewall forward
EAA 84 Edmonds WA
paid 2018
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


All times are GMT -6. The time now is 06:04 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.