VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics

  #1  
Old 06-09-2011, 08:51 PM
bill@fusion4.net's Avatar
bill@fusion4.net bill@fusion4.net is offline
 
Join Date: Feb 2011
Location: Suwanee, GA
Posts: 415
Unhappy Big FUBAR with NACA vent

Well, there is the saying measure twice, cut once. I think I need to amend it tonight and say OPEN YOUR EYES and THINK before measuring the first or second time.

I layed out and cut my NACA vent backwards on my left side for rear vents. (After the skin was on the tail)
https://picasaweb.google.com/lh/phot...eat=directlink
-- Followed the directions, but just getting a link for the photo sorry it did not embed.

Options as I see them:
1. Replace entire left skin...... NOT going to happen
2. Leave as is, use epoxy filler to fill in missing skin.
3. Add a large doubler under the entire NACA vent and recut the hole, still having to add some filler where the skin is missing.
4. Do #3, but also add small pieces in front of the doubler to bring flush to the skin.
5. ?????


Questions, Do I need to add the doubler? What should I fill it with?


I can't believe I did this... ARRRGGG.
Bill

Last edited by bill@fusion4.net : 06-09-2011 at 08:53 PM.
Reply With Quote
  #2  
Old 06-09-2011, 08:58 PM
Danny7 Danny7 is offline
 
Join Date: May 2008
Location: central oregon
Posts: 1,089
Default

have you read this thread?

http://www.vansairforce.com/communit...ight=naca+vent
__________________
nothing special here...
Reply With Quote
  #3  
Old 06-09-2011, 08:59 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 4,435
Default

Hmmm, I wonder if it would work for a cabin air outlet?

Seriously.

Dave
Reply With Quote
  #4  
Old 06-09-2011, 09:30 PM
LeeM_2000's Avatar
LeeM_2000 LeeM_2000 is offline
 
Join Date: May 2009
Location: KS
Posts: 110
Default

Sorry about your fubar. Here is the embed.

Reply With Quote
  #5  
Old 06-09-2011, 09:55 PM
flion's Avatar
flion flion is offline
 
Join Date: Dec 2007
Location: Flagstaff, AZ
Posts: 2,653
Default

Actually, despite the advice I gave in the other thread, this time i would replace the skin. The strength of the design resides largely in the skin and making a patch and doubler to fill the opening would be much more extensive than in the other guy's situation. I know the thought of drilling off the whole skin is horrible but you are talking to the guy who drilled off and replaced his HS skins because of some cosmetic dents.
__________________
Patrick Kelley - Flagstaff, AZ
RV-6A N156PK - Flying too much to paint
RV-10 14MX(reserved) - Fuselage on gear
http://www.mykitlog.com/flion/
EAA Technical Counselor #5357
Reply With Quote
  #6  
Old 06-09-2011, 11:51 PM
ao.frog ao.frog is offline
 
Join Date: Sep 2006
Location: Manstad, Norway
Posts: 866
Default Give...

... Vans a call.... I'm sure they'll point you in the right direction...
__________________
Regards Alf Olav Frog / Norway
First RV-7 completed, (bought partly finished from a US-builder) 305 hrs per July 2014, SOLD
Second -7 had first flight Feb 25th 2014. 220 hrs pr July 2019. Life is good!
Reply With Quote
  #7  
Old 06-10-2011, 02:17 PM
elippse elippse is offline
 
Join Date: Dec 2006
Location: Arroyo Grande, CA
Posts: 938
Default

BTW, those aren't true NACA ducts; they are quasi-NACA ducts since they have somewhat the same shape but definitely not the true dimensions. And unless you have run some definitive comparitive tests between these and a true curved-divergent-submeged duct, don't tell me how well they work. Dang near anything will work, but not well. A much more compact and better-flowing duct would be the NACA parallel-wall-submerged duct. It flows better than a true "NACA" duct at high flow rates, which is really what you want, and it's much easier to make.
Reply With Quote
  #8  
Old 06-10-2011, 08:30 PM
glenn654 glenn654 is offline
 
Join Date: Feb 2005
Posts: 592
Default

Try not to beat yourself up too much. Some days we just shouldn't be in the shop.
I did one much like that and it can be repaired w/o replacing the skin.
I used a solution much like your option 3.
I made a doubler backing plate then made a pattern of the necessary shape
to fill in hole in the skin allowing for the vent opening.
Then I drilled a few holes for riveting and dimpled for countersunk rivets to
attach the doubler to the outer fill in piece.
Then drill the necessary holes to attach the doubler/fill in to the skin, countersink. Also drill the holes to fit the scoop.
Rivet everything in place and mix up some micro to fill in the seam around your fill in piece.
Sand when cured and when painted only you will know what happened....
And I'm sure you'll never tell.


Glenn Wilkinson
__________________
_____________________________________________
RV-4 Sold
N654RV @ MLJ
RV-7 Coming Soon
N987RV Reserved
2015 Donation Gladly Paid

"Maintain Thy Airspeed, Lest the Earth Arise and Smite Thee"
Reply With Quote
  #9  
Old 06-10-2011, 08:36 PM
apkp777's Avatar
apkp777 apkp777 is offline
 
Join Date: Oct 2008
Location: Schaumburg, IL
Posts: 2,053
Default

#4. (blah, blah, blah (message to short with just #4)
__________________
Tony Phillips
N524AP, RV 9 (tail wheel)
Reply With Quote
  #10  
Old 06-15-2011, 07:05 PM
bill@fusion4.net's Avatar
bill@fusion4.net bill@fusion4.net is offline
 
Join Date: Feb 2011
Location: Suwanee, GA
Posts: 415
Default

Thanks for the information, especially for the pointer to the post of someone else who had almost as bad of a mistake. If I did not have his fix as reference I'm not sure I would have come up with as good of a solution, or at least it would have taken a lot longer. 12 hrs of repair later here is my vent.



A full writeup of my repair at:
https://sites.google.com/a/fusion4.n...asterandrepair
__________________
Bill Thomasson
RV-10 - Flying - Phase II. 99.8% done... it's never really done!
http://sites.google.com/a/fusion4.net/rv10/
Suwanee, GA.
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 06:50 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.