Home > VansAirForceForums

-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

VAF on Twitter:

Go Back   VAF Forums > Main > RV General Discussion/News
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Thread Tools Search this Thread Display Modes
Old 11-29-2022, 05:15 PM
claycookiemonster's Avatar
claycookiemonster claycookiemonster is offline
Join Date: Oct 2007
Location: Midway, UT
Posts: 555
Default Is it worth it to try to "expand" wingtips?

Both wingtips are aligned and sized correctly. However, whether due to original molding or storage, one of them is "fuller" while the other is "thinner." One is generally and pleasingly Rubenesque, while the other one looks emaciated.

As far as I can tell, this is totally a cosmetic concern. I could put in a foam "rib" to plump up the thin one, but I'm wondering if in a year or so, after spending time in the sun, they would have equalized anyway? Maybe the relatively invisible "rib" will begin to show and then I'll have an odd ridge in the wingtip?

Is this worth attending to, or should I just learn to not see it?
Clay "Cookiemonster" Cook
USAF: T-38, F-111F
American Airlines: 727, MD80, 757, 767, 737
RV8 #81751 project sold
RV8 #81651 project acquired
Donations up to date thru December 2022

"...serenity...courage...and wisdom..."
Reply With Quote
Old 11-29-2022, 05:26 PM
bjdecker's Avatar
bjdecker bjdecker is offline
Join Date: Jun 2005
Location: Georgetown, TX
Posts: 1,415

Originally Posted by claycookiemonster View Post

Somewhere on here is a thread or 10 that describe in painstaking detail how to add a little more shape to them, and how to stiffen them up under flight loads.

They have a tendency to "pucker" or warp along the top *if* there is the slightest preloading after installation.

Careful not to make them into a Botticelli :O
Brian Decker
RV-7 (Flying)
Reply With Quote
Old 11-29-2022, 05:49 PM
RV8JD's Avatar
RV8JD RV8JD is offline
Join Date: Jan 2005
Posts: 740

Not exactly what you're asking but something to consider ... My RV-8 has the WD-715-1 wing tips and the aft third deforms slightly in-flight as shown in the pic below. The tip of the TE bends upward a smidge and the upper skin buckles downward slightly due to air loads. The overall effect is a 'squeezing' of the aft third of the wing tip. The whole wingtip is very flexible. I try not to push down anywhere on the tip skins, as they flex easily, even when just wiping them down. After 1280 hours there is no cracking in the paint or the glass.

Carl N.

Last edited by RV8JD : 11-29-2022 at 06:10 PM.
Reply With Quote
Old 11-29-2022, 07:49 PM
wirejock's Avatar
wirejock wirejock is online now
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 5,861
Default Sfiffeners

Pretty common to add stiffeners top and bottom fore/aft.
All sorts of methods. I used dowels. Epoxy them by holding them in place with a few strips of waxed lashing string. Remove the strings and layup a layer or two of fiberglass.
If I did it again, I would use fiberglass rod. The stuff the sell at the hardware store with reflectors at the top.
Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog:
Donated 12/2022, plus a little extra.
RV-7A #73391, N511RV reserved
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
Old 11-30-2022, 05:41 AM
Desert Rat Desert Rat is offline
Join Date: Aug 2018
Location: Wichita KS
Posts: 1,101

Clay- When I bought my wings, they had been in storage for about 10 years. The wingtips had been sitting open side down and had pooched out horribly and worse, asymmetrically.

I took the worst of it out with a heat gun and then once they were match drilled to the tips, they sat for about a year on the wings in the wing stand. The Winter/Summer heat cycle seems to have equalized them somewhat.

I figure I'll fly them this way and revisit before paint to see if there's enough deviation that I want to put stiffeners in.
Terry Shortt
AGI, CFI, CFII, MEI, A&P, Janitor
RV7 Empennage & Wing done
Fuselage almost done
Avionics almost done
90% done, 90% to go
Reply With Quote
Old 11-30-2022, 05:57 AM
erich weaver's Avatar
erich weaver erich weaver is offline
Join Date: Aug 2006
Location: santa barbara, CA
Posts: 1,838

I think itís worth the effort to make them look good and be a bit stiffer. I got a few hairline cracks in my paint job from stray hands on the wing tips before I got them stiffened up with a layer of fiberglass. Seems like they should be made a bit more robust.
Santa Ynez, CA
Reply With Quote
Old 11-30-2022, 06:07 AM
KayS KayS is online now
Join Date: Jul 2009
Location: lake constance
Posts: 505

Clay, if you haven't done first flight yet i would try to shape them equally using internal ribs etc. i wouldn't mind for cosmetics but these wing tips could have an significant impact on aerodynamics, especially as they are located most outboard with the longest lever arm. just to avoid painful head scratching later about the causes of the heavy wing etc.

and take care about the trailing edges of the tips... they should be straight and at the same level with the ailerons.
Reply With Quote
Old 11-30-2022, 09:51 AM
BillL's Avatar
BillL BillL is offline
Join Date: Sep 2007
Location: Central IL
Posts: 6,902
Default Great question!

I would suppose you could just install a blocking plate, inflate them and sit in the sun, but you really don't know what it will look like after . . .

I slit the TE of my tips as they were quite misshapen. They were the very old white gelcoat (2002 era). Once the TE termination line was pleasing with the TE of the elevators, the thickness (of mine) was as much as 1/2". I slit the TE and sanded to create an even thickness as the cause was some very thick gelcoat in that area to glue the halves together. After separation and thinning, the pucker was greatly reduced. The ends had been pinched together and the gelcoat glue was reshaping that area.

The gray tips I have seen do not exhibit this characteristic and are lighter.
Reply With Quote
Old 11-30-2022, 11:18 AM
PhatRV PhatRV is offline
Join Date: Mar 2018
Location: KAJO
Posts: 974

I had a warp spot in one of my wing tips after it sat on the hot rafter for 4 years. I fashioned a curve rib from scrap aluminum and Cleco it to the warp area. Use heat gun and generally left the rib attached for a few months. The warp went away. Removed the false rib and filled in the cleco holes with micro
RV8 (N38PV): 90% completed (90% to go)
Days to Final Installation: 999
Days to AWC: 999
Days to First Flight: 999
Painting: 99% completed
Donation paid through 2022
Reply With Quote

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 05:26 PM.

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.