Need opinion on firewall damage

Hello everyone,

I was considering purchasing this completed RV4. I kicked the tires so to speak and though I am not an A&P or a builder I was impressed with the build quality.

Unfortunately the aircraft has some damage history [ a nose over] that was not completely repaired.

The airframe log led me to think the firewall was replaced but there is still some damage visible on the lower starboard corner where the engine mount was pushed into it. Link to photo

http://s583.photobucket.com/albums/ss277/tspooncl65/?action=view&current=rv4firewalldmg.jpg

Any thoughts on this?

Is it easily repairable or should I stay away?

Also the o-320 e2d engine was not torn down after the prop strike.

The prop installed at the time was an IVO pro ground adjustable. Is that composite or metal?

Would an engine tear down be required if it was composite?

I need to decide weather to proceed with a prebuy or not.

Thanks in advance, Tom

Danger Will Robinson said:

The airframe log led me to think the firewall was replaced but there is still some damage visible on the lower starboard corner where the engine mount was pushed into it.

Click to expand...

I am not an expert....

If the build log says the Firewall was replaced, but the firewall shows damages, then I would take a pass not knowing what else had been pencil documented only.


I don't think the type of prop comes into play in a prop strike. If there was a sudden stoppage, then a tear down is in order.

I don't think I would be comfortable with this without a COMPLETE pre-buy by someone very familiar with the RV-4. There have been problems with the lower steel weldments behind the firewall on early -4s. Look carefully at these for cracks or deformities.

Any prop strike of any magnitude with any prop requires a teardown according to Lycoming.

I would have thought that damage was the result of a heavy landing, not a nose over. Perhaps a different incident?

I would pass unless you like lots of work! The proper repair is replace the firewall.

Thanks guys.

I may be wrong about how the A/C sustained the damage.

I know the gear legs were replaced with the tall gear at the same time so perhaps it was a hard landing.

I guess I'll just keep looking.

Having the good or bad fortune to see a lot of bent RV4's (and RV's in general), the truth is that with only one picture it's hard to tell. You really need to get someone who knows these planes intimately to look at it. To be blunt, many RV4's without any sort of damage at all have terribly crinkled and bent firewalls (because of the original builders "finessing" them into place)...but also many times they have been caused by off airport landings, etc..

What I'm saying is that it very well might not be damaged at all, just the way it was built (don't laugh, there are a lot of them that look worse). It also could be from an accident or poor repair job.

At a minimum I'd have the crank dialed and have a very good inspection done on the plane in detail. BTW, I'm not at all impressed with the decision to use a ground adjustable IVOprop and a 320, but that's just me. The plane might be fine or it might be a disaster - impossible for me to tell without seeing a lot more of it up close.

My 2 cents as usual!

Cheers,
Stein

Hey Pierre......

Chime in here about what Vans said about the firewall on the -4's.

Yeah, Bill, I kinda sorta wanted to..

...chime in. A friend of mine stuffed his -4 rather hard into the pavement and splintered his prop. We did the engine rear case teardown and installed a new drive pin in the drive gear along with a new bolt..Both lower corners of the firewall are wrinkled very noticeably, so he called Van's. They said that the wrinkling is pretty common after very hard landings (on the -4's),but if there's no visible damage to the motor mount or steel plates inside the fuselage, go fly it. So that's what we did. The new Catto two-blade that replaced the Sterba is so smooth and also 6 MPH faster.

Seems a shame to have to stuff an airplane to make it faster, eh.

Regards,

The engine should be torn down if there was a prop strike. If the price is right proceed with the pre buy. Plan on $2,000 for replacing the prop to a 2 blade Catto and use that and the things that are found in the prebuy as price negotiation leverage. I would not be overly concerned about the wrinkled / creased firewall, seal it with a firewall sealant and go, if that's the extend of the remaining damage. Be prepared to walk if the numbers are not in your favor.

Good luck.

SteinAir said:

it very well might not be damaged at all, just the way it was built (don't laugh, there are a lot of them that look worse). It also could be from an accident or poor repair job.

At a minimum I'd have the crank dialed and have a very good inspection done on the plane in detail. BTW, I'm not at all impressed with the decision to use a ground adjustable IVOprop and a 320, but that's just me. The plane might be fine or it might be a disaster - impossible for me to tell without seeing a lot more of it up close.

Stein

Click to expand...

I'm starting to think that the firewall may have been damaged during the installation of the engine and/or mount after the firewall was replaced. An aw s**t moment so to speak.

That would explain why the rest of the firewall shows no sign of damage and the airframe log shows it as replaced.

The IVO prop is no longer installed. It was replaced with an aymar demuth during the repair.

I found this info on prop strikes.
http://www.mattituck.com/articles/ss.htm

A quote from the page;

Textron Lycoming, in their Service Bulletin 533A, takes the approach that the safest procedure is to take the engine apart for inspection following any incident involving propeller blade damage. However, they have the caveat that the inspecting mechanic may override that position and return the engine to service without disassembly and inspection if he feels that it is the prudent and responsible thing to do.

Textron Lycoming has also published Service Bulletin 475C which requires, in the event that the engine has experienced a propeller strike, inspection and possible rework of the accessory gear train as well as the rear of the engine's crankshaft. Compliance with this service bulletin is mandatory in the eyes of the F.A.A. by A.D. note 2004-10-14, if and only if, the engine has experienced a propeller strike as defined in the context of the A.D.. It should be noted that to comply with A.D. note 2004-10-14, the engine does not need to be completely disassembled and that access to the accessory gear train can be accomplished, in most cases, with the engine still installed in the aircraft.

What this all boils down to is that in the case of any accidental damage to a propeller installed on a aircraft operating under Part 91 of the F.A.R.'s, it is up to the inspecting technician to determine if the engine should continue in service without total disassembly and inspection. A Textron Lycoming engine, that is being operated on a Part 91 aircraft, that had a propeller strike, must comply with A.D. note 2004-10-14 and Service Bulletin 475C at a minimum.


AD 2004-10-14 was completed and the engine has flown 400 hrs since the repair. Tom