jpw

jpw

Active Member
I need some help with an issue discovered on a prebuy on an RV-4.
Have detected two large wrinkles with breaks in the firewall/footwell area of the plane.
It appears the previous owner( deceased natural causes) did indeed groundloop the plane.
He repaired and covered over the damage with insulating foam.
The gear and fudelage appear straight and the only manifestation of the accident
is in the area about 5 inches above the lowest point of the footwells-firewall
on either side. The motor mount attach point folded the stainless in about 2 inches. When attempting to repair the stainless cracked about 1-2 inches .
Question , even if it appears stupid is; How critical is this area to the structural
integrity of the craft? My sense is that it should be replaced completely.
The area where the longitudinal frame connects to the firewall is undamaged
and the motor mount is not damaged although it looks like it was welded to
repair some hairline cracks.

Thanks for the help.

JPW
 
I think it is critical. I would recommend taking a qualified A&P and get his opinion. You might also try a call to the guys at Van's. I'm not sure for liability reasons if they will answer but it's worth a shot.
 
firewall

I am in Boston ...waitiing for Vans to open..
Tried Saturday no luck.
AP says replacement if manufacturer deems it to be structural component.

Expect Van will confirm this to be the case.
Tks
JpW
 
Firewall Cracks

jpw - the aircraft you are looking at is far from unique. I wrote a bit about it in my blog. See point 3 at http://gikoncnsdr.blogspot.com/2006/05/if-you-are-going-to-build-4-there-are.html#links

I think VANS will say it is not structural and just needs to be gas tight to keep the carbon monoxide out.

If you have not bought it yet though, is it the aircraft for you?

it is THE weak point in the -4 design as far as I can see. Also, the reason I suspect for the totally different U/C design on the -8.
 
jpw said:
I need some help with an issue discovered on a prebuy on an RV-4.
....The motor mount attach point folded the stainless in about 2 inches. When attempting to repair the stainless cracked about 1-2 inches .
Question , even if it appears stupid is; How critical is this area to the structural integrity of the craft? Thanks for the help.

JPW
Click to expand...

This may or may not be applicable, but a RV-4 hangar neighbor recently noticed a slighly deformed fire wall where the engine mount bolts to the airframe. Further investigation, after removing the top skin, revealed that both top corner gussets were broken. The pilot was lucky the engine did not leave the airplane.

Be sure the engine attach points are OK.

dd
 
firewall crack

Steve
Blog very helpful Tks
Appears maybe a reinforcement/rebuild vs replacement may do the trick.

No question about the gas leak risk or fire risk via the holes .
Attach point look OK but definitely an issue as they are 5-6 inches from the
cracked area.

Have not purchased and probably will not too much - history.

Tks

JPW
 
I have a new New Firewall FS

JPW,
If you do want to replace the firewall, I have a new one I'll sell you 20% less than current factory price + shipping from Indianapolis Indiana. It is about a year old. Why do I have a spare one???? I built my FW from sratch...I know...call me strange ;) Let me know and we'll exchange contact info.
Kel
N73KW
 
First of all let me say that I'm an RV-4 owner & fly often.

I agree with most of what all of you have said and would elaborage on some of what has been said.

1. Yes, I agree that the firewall on the -4 is probably the weak point - but not as weak as some on this forum have suggested. I have seen reports here where people say that they have never made a bad landing and their engine mount ended up all twisted up or broken. Maybe they don't know what a good landing is. I have the oldest style of engine mount and firewall - longeron attachments and I've made some pretty bad landings. No sign of the slighest of problems and I've checked and had it checked thoroughly.

2. From my experience and observations the description of the damage to the RV-4 that you have reported suggest to me something more than a simple ground loop.

3. As already suggested I would really inspect the entire firewall system and fuselage back at least 18 inches (or until you run out of damage). Make sure that the longerons, corner brackets and anything related to attaching the engine to the airframe is in good condition. And, when you go to that length, either replace the firewall or at least have it welded where cracked. Finding a good tig welder you can get the airplane to could be the biggest problem.

4. If that kind of damage occured in a ground loop I would also start checking any other areas that could possibly have been damaged such as wing tips etc. Check controls - control serfaces etc etc. Was there a prop strike and if so was the engine torn down and checked?

5. DO NOT CONSIDER THIS A COMPLETE LIST OF WHAT COULD BE WRONG!!! Buyer be ware.

6. I don't mean to be negative but suggest caution and thorough inspection. If you are satisfied with all that you find and the price is right to be able to fix any defecincies then go for it. Good luck
 
update firewall

Just returned from the hangar I inspected the longeron firewall connectors(mounts).
Sure enough, the damage is evident as the mounts have popped the rivets on the longeron side. The bracket is distorted and I am not quite sure what is holding it in place... a bit scary.
I agree,No question the craft was crashed hard- no evidence of wingtip or other fuselage damage but the force required to damage the motor mount, firewall and longeron mount is indicative of a really bad day.
Appreciate the firewall offer and will refer to the present owner he may not have a choice.
Whats really amazing is that the engine was redone completely by Penn Yan and intalled by an IA AP into this damaged craft. It has 0 time at present around 10 K in work done new prop as well.
Would be quite a sight to see that new engine fly off leaving the fuselage behind.
 
OK...I gotta ask

:eek: OK....sorry but I have to ask....is this airplane in Massachussets??

Is it green with an orange stripe on it?

If so....take a GOOD LOOK at the wiring and the plumbing on this plane as well......I never knew you could use household wire-nuts to connect wires on an airplane....you learn something everyday :D . It needs to be ENTIRELY GUTTED and redone. Plus there is a LOT....scratch that....there is a TON of corrosion on the inside of the plane :eek: .

Ask yourself..."if I can see all this....I wonder what condition the stuff is that I can't see" :eek: .

If it's the plane I think it is you better take a another GOOD LOOK INSIDE the NEW engine. It's been sitting on the coast catching waves for a few years with NO PROTECTION and will need ANOTHER teardown and OVERHAUL.
I know the price is low but do NOT BE FOOLED by that :eek: .

All this AND the firewall damage too.....comon'??

Sorry....but unless you get it for FREE you need to pass on this one. I wouldn't put my name on the tailwheel :) .

With the time and money you'll need to 'fix' this thing you'd be WAY BETTER OFF buying one of those 40k RV4's....check on Barnstormers there are plenty of 'em.

If you guys want to see what I'm talking about let me know cause I 'think' I have a few pics....you'll roll over when you see them :D .

Just one man's opinion.
 
Having just re-built an RV-4 that was crashed and with experience in several others I can tell you that the dinged firewall is probably not the result of a ground loop, but more likely a very hard landing (I mean pretty darned hard) or hitting something.

When they are wrinkled that bad, it's highly likely that the lower main (big fat) longerons are either bent, cracked or broke along with the weldments. The last one we worked on had such a hard landing that it bent the gear almost all the way back to the bottom of the wings...but from all outside appearances the rest of the plane didn't look bad and the gear returned to almost normal...sort of. There were some very small telltale wrinkles on the lower side skins, but it looked like you could pound the firewall straight, hang a new engine mount and go fly...I know we could have hidden it if we were unscrupulous. Look closely at the bottom main longerons, along with the center tunnell longerons that run from the spar to the engine mount (where the center engine mount bolts are)...it's likely they've been re-worked as well...or perhaps not, but should have been.

Instead, we rebuilt the entire strcture from the spar forward..firewall and all. NOT an fast, cheap or easy project by any stretch of the imagination. Anyway, if I see an RV-4 with that bump out even wrinkled in the slightest I'd stay far, far away untill the owner can provide some darned good excuse for it and the resultat fixes....If the motor mount was "welded" that's another big red flag. Yes they can be welded, but it's not necessarily the best practice when you can get a brand new one from van's for a few hundred bucks...and you know it's good. Normally when they bend enough to move that footwell area, the top diagonal bars get bent/craked where they join the "ring", look VERY closely there.

There are FAR to many really nice RV-4's out there at good prices right now to even consider fiddling with one like that. I'd just forget it and start looking at others.

Just my 2 cents as usual.

Cheers,
Stein.
 
Not worth it.

We are glad you took the time to dig further. Something had to happen to big time do that much damage. It's just not worth it. If the mounts has shifted that much on the longeron, you never know if there are more cracked stuff you can't with with the eye. :eek: Keep looking for another RV on the market!!! About the pics from the previous post...sure...I'm interested :D
Kel
 
got that right-rv rick

Oh Yeah its the green/orange
Absolutely a nightmare- dime store wiring, filiform corrosion, mickey mouse
details. Its a poster plane for the "how not to build an RV" or " experimentals from ****".
Thanks for the inputs , my friend in SA was interested ,but we have reached
the same conclusions.

Personally, I am looking for a 9 or 9A to go next to my Amphib Elite if anyone has any leads.

All the best


JPW
 
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