What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

RV-7/7A In-Flight Breakup Accident Information

Flutter Testing

Kermit got involved in flutter testing after the loss of a close friend in a flutter accident in a aerobatic monoplane. After the recommended modifications, similar airplanes were trouble free except for one accident in a airplane with a bigger engine and different wing.
A description of the testing and the fix was published in Sport Aerobatics, I think in the early 80's.
 
Gee Bee

The first racing Gee Bee was the Z. The original was lost in a fatal accident during a speed record attempt. After years of speculation it is now believed, as a result of the testing that Kermit had done, that it was aileron flutter. Kermit also owns the Gee Bee R which was built by Delmar Benjamin and Steve Wolf.
Another R is getting close to completion in AZ.
 
As promised, original 7/8 rudder installed.
If nothing else I do think the smaller size looks better!

.
2022090319075883--1131765071990880778-IMG_1905-XL.jpg
 
Last edited:
Round and round we go.

Any luck Bill.

When the insurance company asks if the -7 was built with any non Vans approved mods, it would be helpful to say no.

Then just say no. But making the prove-in-court case is a little more difficult.

Attached is a general fuselage drawing of the early 7. One is with the originally shipped short rudder and the other the replaced tall rudder. Look at the information blocks. They are all the same. I was not impressed with the Vans (publicly available) drawing history control, but it may have been by design for reverse engineering purposes. I have all the other dwg's at the airport and have the short rudder information. The timeline is that the 6 came first. It progressed to a counterweighted rudder with .020 skin. That was the last 6 rudder sold, and the first 7 rudder sold. To actually prove they are the same requires a list of detail dimensions, and materials, and is not available. So you might say the 8 rudder is really the late 6 rudder. I will post the 7PP, 7 and the 6 drawing if I have them.

All straight now?

IMG_6654.jpg

IMG_6653.jpg
 
Can someone with the RV-8 rudder drawing send me a pdf of it (drop me a PM and I'll send my email address)? Maybe I missed it in this massive thread. Would like to get the part numbers off of it. Thanks!
 
Walt, been flying with it yet? How does it feel/handle?

Handles just fine, I did tend to use too much rudder pressure at first, so less pressure required to offset yaw. Kinda like Mark said earlier, power steering.

Any luck Bill.

When the insurance company asks if the -7 was built with any non Vans approved mods, it would be helpful to say no.

The 8 rudder was originally provided with the kit, Van's offered to supply the 9 rudder at no charge if you wanted it, but it was optional, not a required mod.
 
Handles just fine, I did tend to use too much rudder pressure at first, so less pressure required to offset yaw. Kinda like Mark said earlier, power steering.



The 8 rudder was originally provided with the kit, Van's offered to supply the 9 rudder at no charge if you wanted it, but it was optional, not a required mod.

Thanks for the update Walt.

I doubt an insurance company would care.

Thanks for that perspective.
 
Any luck Bill.

When the insurance company asks if the -7 was built with any non Vans approved mods, it would be helpful to say no.

I never heard about Vans approving any mod. They recommend, suggest, discourage, encourage or they are just quite about a mod, but I never saw the word "approved".

Oliver
 
I never heard about Vans approving any mod. They recommend, suggest, discourage, encourage or they are just quite about a mod, but I never saw the word "approved".

Oliver

Well, technically most service bulletins are mods, the forward access hatch is a mod they started selling, the -9 rudder on a -7 is a mod they gave away...so I think approved mod is the correct term.
 
Last edited:
Can someone with the RV-8 rudder drawing send me a pdf of it (drop me a PM and I'll send my email address)? Maybe I missed it in this massive thread. Would like to get the part numbers off of it. Thanks!

These are the part numbers in the 8 rudder kit sold by Vans. I noticed the price went up $20 in the past week. $395 now.

• (2) AN365-1032 view
• (2) AN509-10R16 view
• (1) BAG 402-1 view
• (1) BAG 405 view
• (1) BAG 410 view
• (1) E-614-020 view
• (3) K1000-6 view
• (2) NAS1149F0363P view
• (1) R-405PD view
• (1) R-411 view
• (1) R-606PP view
• (1) R-607PP view
• (1) R-608PP view
• (1) R-703 view
• (1) R-704 view
• (1) R-710 view
• (1) R-713 view
• (1) R-801PP view
• (1) R-802PP view
• (1) R-809 view
• (2) R-815BDE view
• (2) R-815CGA view
• (1) R-815FH view
• (1) AS3-032X1 1/8X40 view
 
These are the part numbers in the 8 rudder kit sold by Vans. I noticed the price went up $20 in the past week. $395 now.

• (2) AN365-1032 view
• (2) AN509-10R16 view
• (1) BAG 402-1 view
• (1) BAG 405 view
• (1) BAG 410 view
• (1) E-614-020 view
• (3) K1000-6 view
• (2) NAS1149F0363P view
• (1) R-405PD view
• (1) R-411 view
• (1) R-606PP view
• (1) R-607PP view
• (1) R-608PP view
• (1) R-703 view
• (1) R-704 view
• (1) R-710 view
• (1) R-713 view
• (1) R-801PP view
• (1) R-802PP view
• (1) R-809 view
• (2) R-815BDE view
• (2) R-815CGA view
• (1) R-815FH view
• (1) AS3-032X1 1/8X40 view

Thank you! Ya I don't think the price increase is just for the rudder parts. I noticed the RV-10 emp went up $100 too.
 
I'm seriously considering switching to the 8 rudder for my 7A. I built the rudder that came with my kit, but the whole time I was building it, I didn't think it felt very robust. Then I stumbled on this thread and it made more sense. I'm sure the factory rudder is fine. But if I can improve my safety margin for $395, then it's worth it. I'm an average recreational pilot and although I'd like to think I won't accidentally do something dumb in flight, it happens. Plus, for what it's worth...I think it looks better, lol.
 
Last edited:
Look at the information blocks. They are all the same. I was not impressed with the Vans (publicly available) drawing history control, but it may have been by design for reverse engineering purposes.
Well, the files were on different drives and in different folders... But yeah, same date, same everything else. That's pretty poor document management.
 
These are the part numbers in the 8 rudder kit sold by Vans. I noticed the price went up $20 in the past week. $395 now.

• (2) AN365-1032 view
• (2) AN509-10R16 view
• (1) BAG 402-1 view
• (1) BAG 405 view
• (1) BAG 410 view
• (1) E-614-020 view
• (3) K1000-6 view
• (2) NAS1149F0363P view
• (1) R-405PD view
• (1) R-411 view
• (1) R-606PP view
• (1) R-607PP view
• (1) R-608PP view
• (1) R-703 view
• (1) R-704 view
• (1) R-710 view
• (1) R-713 view
• (1) R-801PP view
• (1) R-802PP view
• (1) R-809 view
• (2) R-815BDE view
• (2) R-815CGA view
• (1) R-815FH view
• (1) AS3-032X1 1/8X40 view

Also, don't forget to order VS-809 as the VS tip is shorter with the -8 rudder.
 
Then just say no. But making the prove-in-court case is a little more difficult.

Attached is a general fuselage drawing of the early 7. One is with the originally shipped short rudder and the other the replaced tall rudder. Look at the information blocks. They are all the same. I was not impressed with the Vans (publicly available) drawing history control, but it may have been by design for reverse engineering purposes. I have all the other dwg's at the airport and have the short rudder information. The timeline is that the 6 came first. It progressed to a counterweighted rudder with .020 skin. That was the last 6 rudder sold, and the first 7 rudder sold. To actually prove they are the same requires a list of detail dimensions, and materials, and is not available. So you might say the 8 rudder is really the late 6 rudder. I will post the 7PP, 7 and the 6 drawing if I have them.

All straight now?

View attachment 30481

View attachment 30482

Bill, do you have a photo of this sheet of the early -7/7a rudder?
 

Attachments

  • _8-rudder.jpg
    _8-rudder.jpg
    194.3 KB · Views: 165
Just for you Michael:

The first drawing says RV7,8 in the title block. A change notes it once said 7,8,9!!

IMG_6659.jpg

IMG_6660.jpg

IMG_6661.jpg
 
Last edited:
hey guys is it just the fibreglass top different on the VS if i fit an 8 rudder to my 7...i have not yet done the fibreglass top of the VS. Im seriously considering getting the entire 8 rudder to build and just using the 7 rudder as practice. I personally think it looks better on the 7 and not worried about spin recovery...I dont intend to spin it or get into inadvertent spins anyway. Plus its obviously stronger and lighter.....for me its a no brainer....I understand the 9 rudder is on a lot of 7's and is absolutely fine....i'm not trying to re invent the wheel or distrust the manufacturers design skills...just reading between the lines and seeing wind damage, the look of the rudders on the 7 and anecdotal evidence of the strength difference tips me toward the 8 rudder.
 
After reading through the multitude of pages, I am quite interested in all the information, knowledge and thought processes. It has definitely been a good learning and thought invoking read. Questions raised as I was reading; does anyone know the process used to “bond” the trailing edge wedge before riveting and/or if there was a strobe light installed in the rudder fairing of the accident aircraft? My thought is if there was proseal used along with RTV at the stiffeners, this with a possible OG strobe light installed, all at the far rear of the rudder, this would exacerbate the flutter potential of an already (collective opinion) slim margined rudder. How well were the rivets set along the edge ? Could this be part of or THE reason Vans now recommends using the VHB tape?

Just thoughts that arose while reading and thinking, thanks for entertaining my brain. Haha
 
I have used VHB tape a lot….but no way I’d use it in the trailing edge. It assumes you get the pieces aligned perfectly prior to the tape touching. If you are out a smidge and the skins touch the tape it can stick immediately. I have built a trailer for gokarting and used tape exclusively to stick the sides and top on etc….it’s truly amazing stuff….so incredibly strong….but I wrecked one panel not getting it aligned correctly and trying to remove it….
 
I have used VHB tape a lot….but no way I’d use it in the trailing edge. It assumes you get the pieces aligned perfectly prior to the tape touching. If you are out a smidge and the skins touch the tape it can stick immediately. I have built a trailer for gokarting and used tape exclusively to stick the sides and top on etc….it’s truly amazing stuff….so incredibly strong….but I wrecked one panel not getting it aligned correctly and trying to remove it….

I used it and didn’t have any issues… the tape they recommend has a cure time and you can peel it back up if you don’t get it exact. I was comfortable using it over pro seal because it isn’t “suppose” to have anything to do with the final bond.
 
I used it and didn’t have any issues… the tape they recommend has a cure time and you can peel it back up if you don’t get it exact. I was comfortable using it over pro seal because it isn’t “suppose” to have anything to do with the final bond.

That’s good to know. How thick is it? Most VHB tapes have a structural strength and the stuff I used was a pressure sensitive tape but still stuck immediately it touched. You peel it off it stretched and would not go back down flat so had to start again. Important not to stretch it and I’m imagining if you put it on with more tension on one side than the other it might like to “bend” things? Also how did you cut holes in it? Just interested to know your experience with it. Cheers
 
Last edited:
F/A-18E/F's use Scotch VHB tape to hold composite cuffs on the trailing edges of the rudders. They look similar to taco shells.

That VHB tape does have an expiration date, and I remember it having a fairly short shelf life.
 
That’s good to know. How thick is it? Most VHB tapes have a structural strength and the stuff I used was a pressure sensitive tape but still stuck immediately it touched. You peel it off it stretched and would not go back down flat so had to start again. Important not to stretch it and I’m imagining if you put it on with more tension on one side than the other it might like to “bend” things? Also how did you cut holes in it? Just interested to know your experience with it. Cheers

It’s very thin, I’d say no more that 1-3 thousandths, pretty much just adhesive layers. As for the holes, you simply just poke the clecos through it. Use a long piece of angle to keep things nice and straight and then rivet away.
 
Im seriously considering getting the entire 8 rudder to build…not worried about spin recovery...I dont intend to spin it or get into inadvertent spins anyway.

And even if you were worried, posts like the following anecdotally show the smaller rudder is just fine wrt spins.

I have a RV-7 with the small rudder…
I did my spin and aerobatic testing with an aerobatic/unusual attitudes instructor on board…We both did left and right spins, up to three an a half turns. My instructor was very happy with how it behaved and the rate at which it recovered. He even said “this thing recovers almost as fast as my Pitts”.
 
Last edited:
It’s very thin, I’d say no more that 1-3 thousandths, pretty much just adhesive layers. As for the holes, you simply just poke the clecos through it. Use a long piece of angle to keep things nice and straight and then rivet away.

Thanks for the info. Very different stuff than I have used in the past. I think the stuff I used was construction tape. It’s pressure sensitive and has small cells in it. When pressured the cells break causing the glue inside to “mix” and bond the surfaces with an epoxy like bond. Or something like that.
 
RV7/7A

So what appears to be hidden in this thread is that the concern is really only on the RV7/7A planes.

I am a 9A builder, I assume there are no more than a few, if any, 9/9A's that have had a similar failure??

In addition, the 9/9A needs the larger rudder due to the longer wings, so we all have no choice in tails.
 
So what appears to be hidden in this thread is that the concern is really only on the RV7/7A planes.

I am a 9A builder, I assume there are no more than a few, if any, 9/9A's that have had a similar failure??

In addition, the 9/9A needs the larger rudder due to the longer wings, so we all have no choice in tails.

The 9 is not the same aircraft and has a different operating envelope more suited to the rudder that has been designed for it. The rudder has been retrofitted to the 7.
 
There's more margin in the RV9, The VNE for the RV9 is 210mph TAS and the RV7 is 230mph TAS. Thanks for catching that Carl.
 
Last edited:
For those with steam gages, and those with EFIS' that have not set Vne in terms of TAS.

i-t32pVQR-M.jpg
 
Last edited:
Does this chart factor in the standard decline in temperature with altitude?

Yes, it does take the temperature lapse rate into account. It's based on the 1962, 1966, or 1976 U.S. Standard Atmosphere (I forget which one, but they are all similar, if not the same, for the altitudes in the charts above).

Please feel free to spot check a few of the numbers.
 
Last edited:
Steam Gage IAS if rudder has narrow Vne margin for error

For those with steam gages, and those with EFIS' that have not set Vne in terms of TAS.

i-t32pVQR-M.jpg

Thanks for the reminder Carl, I was aware of this but was previously less concerned with it, until this thread & learning of the possible -9 rudder's narrow margin for error with respect to -7's Vne. I suppose if I do decide to keep my -9 rudder on my -7 then probably should consider having an EFIS -and with a good audible alert.

I wonder if anybody knows of Van's position on this issue yet?
My instinct is to stick with what they provide, but if the -8 rudder on a -7 was at least an option that they endorsed then I'd be more likely to consider it.

Thanks again, and I REALLY appreciate all the input this thread is drawing, yay for VAF!
 
I wonder if anybody knows of Van's position on this issue yet?
Unfortunately, I think Van's will continue to remain silent about the -7/-9 rudder, whether it's flutter margin or using the -8 rudder, until/unless there's concrete evidence that a problem exists within the -7's cleared operating envelope. As far as I can tell from the US and Australian accident investigations that Carl is tracking, that evidence doesn't exist. Someone please correct me if I'm wrong.

Back in 1998 when a factory demonstrator RV-8 (N58RV) experienced a wing structural failure during a demo flight, Van's went to great lengths to test the -8 wing and show that it was sound, then shared all the information they had to maintain confidence in their product. For the same reason, given the questions in this thread and elsewhere over the -7 tail/-9 rudder combination I think it's time for Van's to address the question as they did with the -8 wing.

ds
 
Last edited:
Vans

I think it's way past time for Vans to reveal just what testing was done with the RV9 rudder and provide more specifics on the spin testing with the original rudder.
 
I think it's way past time for Vans to reveal just what testing was done with the RV9 rudder and provide more specifics on the spin testing with the original rudder.

What other kit manufacturers publish their testing methods and specifics on each model?
 
Back
Top