|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

03-30-2013, 07:16 PM
|
|
|
|
Join Date: Mar 2007
Location: Sonoma County
Posts: 3,821
|
|
Also keep in mind that the wing was stress tested without this skin attached. If this is the ONLY thing keeping you from purchasing the aircraft, then purchase it and correct it later. This is not a big deal to fix without removing the wings.
__________________
VAF #897 Warren Moretti
2019 =VAF= Dues PAID
Last edited by gasman : 03-30-2013 at 07:33 PM.
|

03-30-2013, 09:27 PM
|
 |
|
|
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
|
|
Quote:
Originally Posted by FitzRX7
So the consensus seems that if you can spell strength, the screws are required. A couple questions then.
If the seller was unwilling to pay to install the screws, and unwilling to lower the price enough so that I could pay to have them installed, how can I:
1 - Insure that everyone who might try to buy this plane is aware of this problem so they don't buy it and have the wings fall off?
2 - Recover my good-faith deposit that the seller has refused to return to me, citing that the plane has flown fine for a short time, and that 2 random people say the screws aren't needed.
I understand that specifics of the aircraft shouldn't be cited here.
Also, does anyone know if the DAR or FSDO that originally signed off the plane would pull the airworthiness certificate knowing this, or because it's an experimental is pretty much anything acceptable?
Thanks again for all the information, you guys are amazingly knowledgable!
|
1 - It is not your responsibility to tell everyone else, but I understand your feeling. No one said the wings would come off without the screws. I have been involved in wing tests. I have witnessed the screws carrying load. How much? Know one knows. That is why with things like this, you do not play games and randomly decide to not install them. I said it before, but I will say it again... any RV that has blatantly visible shortcuts taken during construction, how do you know what's there that is not visible?
It doesn't mean what random people have said. There is no argument that the airplane wasn't built per plans. Period.
2 - The seller is being totally unreasonable. This is exactly the type of issue that warrants a refund. It is not like you decided you didn't like the color.
A deficiency was found that you can't come to an agreement on to rectify. He should be reasonable and let you walk. If he doesn't, my gut feel is that it is probably not an airplane worth being serious about anyway.
Also, it is possible to find people willing to say anything we want them to say. It happens in the court of law all the time.
I guess you had nothing in writing requiring your deposit be returned if any deficiency were found? Did someone experienced with RV-6's do a thorough inspection for you? If not, then as many of us have already said, there could be other surprises hiding in this airplane.
Your last ?... It is highly unlikely that anyone would pull the C of A on this airplane.
|

03-30-2013, 09:34 PM
|
 |
|
|
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
|
|
Quote:
Originally Posted by gasman
Also keep in mind that the wing was stress tested without this skin attached.
|
Also keep in mind, the above can only be said about the RV-6 wing.
All models after that were tested with the wings installed on a forward fuselage / center section.
|

03-31-2013, 09:08 AM
|
 |
|
|
Join Date: Jan 2007
Location: Battleground
Posts: 4,348
|
|
Quote:
Originally Posted by gasman
This is not a big deal to fix without removing the wings.
|
Tell me how you would do it. Locating the rib flange under that skin from the bottom woukd be hit and miss. Drilling it from the top through a one inch gap up against the fuselage side I can't imagine. If you get that far dimpling might be possible with a pop rivet dimpler but I have not had good luck with them.
Perhaps I am not seeing things clearly.
__________________
Smart People do Stupid things all the time. I know, I've seen me do'em.
RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
|

03-31-2013, 09:31 AM
|
|
|
|
Join Date: Feb 2006
Location: Trenton, SC
Posts: 117
|
|
Quote:
Originally Posted by az_gila
Are they pre-punched on the RV-7?
I thought they were #40 holes and you leave out every third rivet and drill out for a #8 screw later.
I bet a lot of the should be empty rivet holes got filled...
I think this particular row of holes may be in the pre-punched 0.1%...
|
The holes for the nutplates on the wings where prepunched on the 7 , had to use hole finder to locate the holes on the fuselage overlap. Then you have to pull the wings back out to dimple the screw holes. Would be difficult with the wings permanately attached.
|

03-31-2013, 11:23 AM
|
|
|
|
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,218
|
|
Quote:
Originally Posted by JonJay
Tell me how you would do it. Locating the rib flange under that skin from the bottom woukd be hit and miss. Drilling it from the top through a one inch gap up against the fuselage side I can't imagine. If you get that far dimpling might be possible with a pop rivet dimpler but I have not had good luck with them.
Perhaps I am not seeing things clearly.
|
With careful measuring, you could drill the holes from the bottom. With a 12" drill bit run through a piece of tubing, you could drill it from the top. Instead of dimpling the 0.040 skin, why not go with button head screws from the underside with nyloc nuts on the inside? A little tape to hold the nut(s) in a socket extension and attaching the nuts would be fiddly, but doable.
I'd guess someone efficient, working with a helper, could do the whole thing in a couple of hours. I'm a little slower than that.
__________________
Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
|

03-31-2013, 12:38 PM
|
|
|
|
Join Date: Jul 2006
Location: Ione, California
Posts: 254
|
|
To be screwed on not to be screwed.
I was talking to Ken Kruger several years ago about doing pre-buy inspections and asked if there was anything he felt was important that was sometimes missed. He specifically said the screws that attach the lower skin of the wing to the belly skin were sometimes omitted, and that they were structural.
As for an DAR missing them, I believe that most of the DAR's inspect lot's of different types of aircraft and can't be expected to know where all of the bolts and screws go or need to be on each aircraft type. They inspect what it there and with there knowledge and experience look for things that would commonly be incorrect as per 43-13b. There are DAR's that limit themself's to, or do a lot of RV's and have built at least one for themself's, I would expect them to have a better base knowledge of Van's aircraft. It's hard to inspect something that is not there.
RT
|

04-01-2013, 06:53 AM
|
|
|
|
Join Date: Jun 2005
Posts: 846
|
|
wing
I would quess that the RV 3-4 and 6 were tested without a center section in place when loaded to failure.
Bob
|

04-07-2013, 01:26 PM
|
 |
|
|
Join Date: Oct 2009
Location: Victoria, BC, Canada
Posts: 3,932
|
|
So as it turns out, mine doesn't have them either! I never knew... The builder did put some thought into that joint, however, as he did finish the edge with the edge rolling tool to give it a slight bend. As a result, the skin sits very nicely against the bottom of the wing. I don't think it's a case of laziness by the builder, as attention to detail on the metalwork on the plane is excellent everywhere... The builder planned from the start to to polish, and it wouldn't do to have bad metalwork.
I suspect he looked at the plans and saw nutplates on top holding a filler fairing, and saw nutplates on the bottom performing what looked like the same purpose. Knowing he could get a nice fit with an edge-rolled sheet, that's the choice he made. There is no evidence of any flexing in this area, and no sign of the belly skin moving relative to the wing skin... No little scratches that would indicated any motion. And that's after over 600 hours of trouble-free flight, at least some of which has included aerobatics.
It appears from the comments in this thread and others, that the past questions about the belly screws were specifically in relation to the 7/7A, which has a different wing mounting configuration, and the 7/7A wing configuration was tested with that skin screwed in place. It further appears that the 6/6A wing was tested *without* that skin screwed in place.
The other thing that comes to mind here is that relying on this skin to take a structural load is kind of counter to how an airplane is traditionally designed... Typically you rely on the skins to transfer the load to the spars, and the spars to transfer the load to the fuselage. Anything else is a bonus, but not something you should be counting on.
I will have to think about this further... I'll go grab the plans from the hangar and run some numbers and see what kind of effect those screws would have. But when you compare the load-bearing capability of 10 #8 screws to the load bearing capability of the spar itself, I'm not sure the effect is going to be significant...
__________________
Rob Prior
1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
|

04-07-2013, 04:06 PM
|
 |
|
|
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
|
|
I know it is beating a dead horse... but regardless of how much thought appears to have gone into deleting these screws (or anything else), it is still a deviation from the original design.
In my mind, this opens the door for the potential of other dangerous deviations that may be far less obvious.
I in no way mean to imply that an RV not built exactly per the plans is a death trap... but it might be.
Also, making comparisons of different models with just a very small amount of publicly known info regarding differences of how they were tested, is not a good way to decide on whether a modification is sound or not.
It has been pointed out that at one time the head of engineering at Van's stated the screws in question were considered structural (and I agree with him). This is a person that oversaw the design of wing spars and other major structure. Most everyone excepts the viability of of those without question, but then they second guess the need for some screws which the same engineer said he felt were important?
Venting mode now on...
I am endlessly amazed at how many people will add weight to their RV, beefing up this and that "because it just didn't look strong enough", but then casually dismiss something else because to them it appeared rather insignificant....
sigh...
vent mode off now....
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 01:45 AM.
|