RV-4 wings folded

[Infidel]

Obviously the story has some variables. Maybe in the 1980's and so on leads me to believe it is more likely a -3 the guy was talking about. Adding 2 fatalities, well, stories change and get crossed over time.

IIRC, there were a few earlier model -3's that had wing spar issues/failure. I've read so many RV related NTSB reports so it's possible I may "cross" some of those but I seem to recall reading a report on a -3 where the wings were folded/over stressed in flight. Perhaps more than one which led to Vans developing the SB for the wing/spar.

[Chkaharyer99]

Courtesy of our VAF site administrator, you can conduct research about accidents here: http://www.vansairforce.net/AccidentsAndSynopsis.htm

"At this link, you can find over (500) RV probable cause documents published over the last quarter century:"

If it happened and was documented, its probably in there.

[Michael Henning]

I thought there was a -4 that had a rear spar attach point fail (improper edge distance, as in not enough), allowing the wing to seperate.

[rvbuilder2002]

Originally Posted by Michael Henning

I thought there was a -4 that had a rear spar attach point fail (improper edge distance, as in not enough), allowing the wing to seperate.

Not that I have ever been aware of.

The only incident I am aware of that is remotely similar was an RV-4 purchased by someone for the purpose of doing aerobatics. It then got damaged somehow but not during flight (I don't remember that detail.... storm damage, taxi accident, ???

During an extensive inspection and rebuild it was discovered that the rear spar attach points had never been drilled/bolted

[flyboy1963]

Originally Posted by Billythekid

I was talking to an older gentleman this week and was kicking the idea of buying his kit unbuilt rv4. We got to talking and he said that a rv4 was being tested down in the imperial county ca and when big daddy van was present and a few others , the plane was flying and did a maneuver and folded the wings! Is there any truth here? Circa 1985,6 7,8 or 9

Much like building an RV, this forum pretty much exists for the 'education and recreation' of the individuals participating.
Sounds like this gentleman is not doing the best marketing for his RV-4 kit, except perhaps that he's not keen to build if the design has some fatal flaw.
Kudos to Scott for commenting; really, if the question is: does the -4 have a problem?
the answer, as with almost everything; not if built and operated per the designers intent.
It appears a thousand+ views of this thread demonstrate the concern and involvement of the community, (but perhaps the title is a bit sensational?)

[Michael Henning]

Scott,
That RV-4 you are talking about was purchased from the original builder who scratch built the wing spar, omitting all of the spar flanges. He flew regular aerobatics with it while carrying passengers. It was sold, the new owner had a dead battery, tied the tail up, cracked the throttle open, and hand started it. The knot came undone and the airplane was free to roam the airport. It finally hit something that required the wing to be opened up, exposing what one would think would be a instant fatal flaw. To the credit of the designer, the plane held together in spite of missing half of the spar.

[rvbuilder2002]

Originally Posted by Michael Henning

Scott,
That RV-4 you are talking about was purchased from the original builder who scratch built the wing spar, omitting all of the spar flanges. He flew regular aerobatics with it while carrying passengers. It was sold, the new owner had a dead battery, tied the tail up, cracked the throttle open, and hand started it. The knot came undone and the airplane was free to roam the airport. It finally hit something that required the wing to be opened up, exposing what one would think would be a instant fatal flaw. To the credit of the designer, the plane held together in spite of missing half of the spar.

Thanks.
That is the one I was thinking of.....

[smokyray]

Originally Posted by Billythekid

I was talking to an older gentleman this week and was kicking the idea of buying his kit unbuilt rv4. We got to talking and he said that a rv4 was being tested down in the imperial county ca and when big daddy van was present and a few others , the plane was flying and did a maneuver and folded the wings! Is there any truth here? Circa 1985,6 7,8 or 9

Billy,
In my 28 years associated with the RV4 there has never been a documented in-flight wing failure. The 4 wing wasn't designed by Van, but by a friend after several RV3's had spar failures. The RV6 wing is nearly identical and when Van tested it in 1986 he invited the FAA. They piled sandbags on it until ultimate load (9G's) was reached with no buckling. The FAA left and they continued piling bags on the wing until it slightly deformed and popped some rivets. It never broke. Where the deformation occurred was a trade secret but my friend who witnessed the event said it was in excess of Eleven G's.
Having pulled 9G's regularly for 21 years in the F16 I can assure you Eleven would incapacitate you before you could fail the wing.

Yes, an RV8 demonstrator from Van's had a wing failure during a demo ride in AZ in 1998 with 2 fatalities and subsequent law suit. The RV8/7wing spar differs from the 4/6 in that it has one solid billet of aluminum extrusion. The 4/6 use layered aluminum planks very similar to the Cessna 172.
Here is the NTSB report:http://www.ntsb.gov/_layouts/ntsb.av...98FA171&akey=1

Your friend was passing inaccurate information I am certain.
V/R
Smokey

PS: After the RV8 wing failure Van recalled all the early RV8 kits for a "wing modification". The rest as they say is history...

[Kevin Horton]

Originally Posted by smokyray

PS: After the RV8 wing failure Van recalled all the early RV8 kits for a "wing modification". The rest as they say is history...

You sure about that? There is no SB listed on the Van's web site, and I certainly don't recall ever seeing one.

I was working on the wing of my RV-8 at the time of the accident. I paused working for awhile, in case the investigation triggered any requirement for rework of my wing. Van hired FAA delegate structural engineers to review the wing design and supervise static load tests using a wing that had been assembled by a builder. The wing passed the FAR Part 23 aerobatic category requirements. No design changes were required.

Van did later slightly revise the wing design when the RV-7 came out (the RV-7 and RV-8 use the same wing). The later wing design has a recommended aerobatic weight that is 50 lb higher than the original wing.

[rvbuilder2002]

Originally Posted by Kevin Horton

You sure about that? There is no SB listed on the Van's web site, and I certainly don't recall ever seeing one.

I was working on the wing of my RV-8 at the time of the accident. I paused working for awhile, in case the investigation triggered any requirement for rework of my wing. Van hired FAA delegate structural engineers to review the wing design and supervise static load tests using a wing that had been assembled by a builder. The wing passed the FAR Part 23 aerobatic category requirements. No design changes were

Van did later slightly revise the wing design when the RV-7 came out (the RV-8 and RV-8 use the same wing). The later wing design has a recommended aerobatic weight that is 50 lb higher than the original wing.

Totally correct Kevin ( except I think you meant to say the RV-7 and RV-8 use the same wing).
There was never any recall or mandatory design change of the RV-8 wing.