Van's Air Force
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bad install of firewall engine mount weldments
- Thread starter CATPart
- Start date
Decisions!!!
Well if this is what has been done where you can see it...... what has been done where you can't????
This is one of the problems when buying second hand or part built..... you are buying someones mistakes and bodges!! We all make mistakes when building, some are fixable,some reduce the part you have messed up on to scrap.
Even if this 4 was very cheap I would be hesitating about buying it, putting things right can cost a fortune in parts and time.
Well if this is what has been done where you can see it...... what has been done where you can't????
This is one of the problems when buying second hand or part built..... you are buying someones mistakes and bodges!! We all make mistakes when building, some are fixable,some reduce the part you have messed up on to scrap.
Even if this 4 was very cheap I would be hesitating about buying it, putting things right can cost a fortune in parts and time.
Repair
These lower firewall corner brackets are under a fair amount of stress in a -4, since they bear the brunt of landing loads. You could ask Vans, but this looks unacceptable in my book (i.e., it should definitely be repaired to avoid future problems).
You can replace these brackets (I did it on my -4 rebuild project), but to do the job properly, you also have to replace the side skins, lower longerons, and probably the firewall supports as well. It's a big job, and best done in the shop with wings, engine, and instrument panel all stripped from the airframe so you can build a jig to support everything during the repair.
The market for -4s is pretty depressed right now, so you might want to just shop around.
M
These lower firewall corner brackets are under a fair amount of stress in a -4, since they bear the brunt of landing loads. You could ask Vans, but this looks unacceptable in my book (i.e., it should definitely be repaired to avoid future problems).
You can replace these brackets (I did it on my -4 rebuild project), but to do the job properly, you also have to replace the side skins, lower longerons, and probably the firewall supports as well. It's a big job, and best done in the shop with wings, engine, and instrument panel all stripped from the airframe so you can build a jig to support everything during the repair.
The market for -4s is pretty depressed right now, so you might want to just shop around.
M
Thanks all. I needed to hear all of this. This is only the ugliest of what I found...more of this type of error, short ed, etc. It is a statement on the overall ethic of the builder to leave something so ugly so obvious, and yes what about the hidden. I would never feel confident. I should know better than to be interested in it, and I don't want to get into any lengthy fixes.
pierre smith
Well Known Member
David Paule
Well Known Member
Not only the riveting --
Sharp inside corners where the flanges of the angles were removed with no fillet radii.
Dave
Sharp inside corners where the flanges of the angles were removed with no fillet radii.
Dave
How many hours?
How many hours on that RV-4 ?
I can't disagree with what has been said but this RV probably has a lot of time on it and hasn't developed any cracks or other weaknesses from what I see.
It's not pretty but you could probably use that poor example of craftsmanship as a good bargaining chip.
After going to flyins for years I have seen many RVs with literally thousands of hours and much worse building quality happily flying along and not falling apart.
How many hours on that RV-4 ?
I can't disagree with what has been said but this RV probably has a lot of time on it and hasn't developed any cracks or other weaknesses from what I see.
It's not pretty but you could probably use that poor example of craftsmanship as a good bargaining chip.
After going to flyins for years I have seen many RVs with literally thousands of hours and much worse building quality happily flying along and not falling apart.
This one has 300 hours on it. I hear ya about things flying for a long time with bad work. Trust me it happens with certified aircraft also. I draw the line at primary structure and i consider this to be primary. It may be flyable but i would never have peace of mind especially with passengers. First they see the word experimental and you must assure them it is safe, I dont want to lie. I dont think this would cause catastrophic failure, but it is a fatigue issue, and difficult to quantify. That is the beauty of good workmanship, it is easy to quantify. I have spent months trying to prove that an aircraft is safe to fly with a misdrilled hole in its primary structure. Some might not believe the difference .050 inch can make.
Yes, you are correct...certified aircraft have not escaped. They just have a certified sig to go with it. The bottom line as you mention is how well do you sleep at night. Then again, I am always amazed how resilient aircraft building must be when virtually all of the accidents are caused by a pilot decision, not a builder one. Go figure. In this case, I am assuming you are the pilot so yes, now is the time to run.
ColoRv
Well Known Member
I sometimes wonder if half of the people in here would fall dead from heart failure if they ever checked the riveting of the nearest Cessna or other certified aircraft and they seldom snap in half and fall from the sky. A buddy of mine used to work on military transports and they had one come back for some work after flying for years overseas. When they pulled the wing skins off, the entire structure was cleco'd together (power clecos)....clearly someone had made a mistake, but it flew fine.
I'm not saying this RV4 is airworthy....but I would be talking to Vans about it if I were looking to buy. There are very few area in an aircraft where the load isn't spread out over many many rivets. This particular area has welds, bolts and rivets adding strength. Not average workmanship for RVs to be sure, but scrap? Junk? Hmmm..I would call Vans, and with their blessing...I would consider this picture a bargaining chip. Now if Vans said run....then I would. As a Vans employee once told me, 99% of the opinions on the internet are horribly misinformed, are certain they know everything there is to know, but have very little understanding of the actual engineering involved. Most judge on is it pretty, not is it structurally sound.
Just my .02, worth about as much as the riveting skills of that builder.
I'm not saying this RV4 is airworthy....but I would be talking to Vans about it if I were looking to buy. There are very few area in an aircraft where the load isn't spread out over many many rivets. This particular area has welds, bolts and rivets adding strength. Not average workmanship for RVs to be sure, but scrap? Junk? Hmmm..I would call Vans, and with their blessing...I would consider this picture a bargaining chip. Now if Vans said run....then I would. As a Vans employee once told me, 99% of the opinions on the internet are horribly misinformed, are certain they know everything there is to know, but have very little understanding of the actual engineering involved. Most judge on is it pretty, not is it structurally sound.
Just my .02, worth about as much as the riveting skills of that builder.
David,
The guy who did this is clueless. Rivets should never be installed with less than 3X [3 times the diameter of the rivet] between them. Obviously, he replaced the weldments. He should have installed the replacement rivets half way between the originals, not placed them right next to the originals.
This was a common problem on the 4, caused by hard or bounced landings. In the RVator, Van recommended placing a gusset between the firewall and the top of those weldments. When the 8 was designed, that gusset was designed in. The first sign of this problem on a 4 is that the SS firewall will wrinkle near those weldments [visible from the engine compartment side]
When you finally find a 4 worth buying, make sure it has the gussets installed, or plan on installing them yourself [a fair amount of skilled work]
I don't have a high resolution photo of this area. I will take one tomorrow and post it, so that you can see what the gusset should look like.
Charlie
The guy who did this is clueless. Rivets should never be installed with less than 3X [3 times the diameter of the rivet] between them. Obviously, he replaced the weldments. He should have installed the replacement rivets half way between the originals, not placed them right next to the originals.
This was a common problem on the 4, caused by hard or bounced landings. In the RVator, Van recommended placing a gusset between the firewall and the top of those weldments. When the 8 was designed, that gusset was designed in. The first sign of this problem on a 4 is that the SS firewall will wrinkle near those weldments [visible from the engine compartment side]
When you finally find a 4 worth buying, make sure it has the gussets installed, or plan on installing them yourself [a fair amount of skilled work]
I don't have a high resolution photo of this area. I will take one tomorrow and post it, so that you can see what the gusset should look like.
Charlie
Glad to see I have a little company with my opinion.
It would be nice to see more of the rest of the airplane. Is this the only thing that bothers you or have you come across other questionable workmanship?
Are you someone with some building experience or are you just looking for something that's ready to fly and won't need anything done to it for as long as possible. It all plays into this decision. There are many Rvs available many with exceptional workmanship for a price of course.
That engine mount bracket is a very difficult place to rivet especially when you have to drill all your own holes. It's hard enough with pre-punched holes.
You could probably drill 3/16" holes where those double rivets are located and use countersunk #10 screws. With any luck you'll capture both of those half holes and make one nice large hole for a screw.
Certainly, if Van says run, find another RV.
It would be nice to see more of the rest of the airplane. Is this the only thing that bothers you or have you come across other questionable workmanship?
Are you someone with some building experience or are you just looking for something that's ready to fly and won't need anything done to it for as long as possible. It all plays into this decision. There are many Rvs available many with exceptional workmanship for a price of course.
That engine mount bracket is a very difficult place to rivet especially when you have to drill all your own holes. It's hard enough with pre-punched holes.
You could probably drill 3/16" holes where those double rivets are located and use countersunk #10 screws. With any luck you'll capture both of those half holes and make one nice large hole for a screw.
Certainly, if Van says run, find another RV.
Right, it surely isn't pretty; but it can be properly repaired. Time & $$ is what it takes. I've seen some beautiful restoration jobs. I'm not suggesting; just saying....
Cheers,
David,
I just stumbled on a photo of the gusset I mentioned in my first post. It is on the bottom photo of this post on Tony's build page, linked below. Look at the lower/right corner of the structure. The gusset has a lightening hole in it. See
http://www.vansairforce.com/community/showpost.php?p=724469&postcount=111
Charlie
I just stumbled on a photo of the gusset I mentioned in my first post. It is on the bottom photo of this post on Tony's build page, linked below. Look at the lower/right corner of the structure. The gusset has a lightening hole in it. See
http://www.vansairforce.com/community/showpost.php?p=724469&postcount=111
Charlie
I will post this for the interest of the conversation, though i think my mind is made up on this one, and i am not looking to fix any structure. Here is a link to some other photos. You will see: double rivets on the frame at the passenger seat back, rivets with short ed on the lower wing skin, an open misdrilled hole in the top wing skin, misdrilled row of holes on bottom of fuel tank, other weldments. None of this is too terrible, just ugly. I did not look under the floor panels yet. It is also a narrow deck, which is not my ideal choice, but that is for a different conversation.
https://picasaweb.google.com/m/view...10884822851297&start=0&source=mog&hl=en&gl=us
https://picasaweb.google.com/m/view...10884822851297&start=0&source=mog&hl=en&gl=us
Gee, where to start? If I was you I would sprint away from it not run!!
I have never seen workmanship this bad and in so many places. Makes you wonder what the main wing spar looks like The early RV4's had the option of the builder assembling the main spar.
The question remains, how did this aircraft get signed off to fly with workmanship like this
I have never seen workmanship this bad and in so many places. Makes you wonder what the main wing spar looks like
The early RV4's had the option of the builder assembling the main spar.The question remains, how did this aircraft get signed off to fly with workmanship like this
Last edited:
pierre smith
Well Known Member
The question remains, how did this aircraft get signed off to fly with workmanship like this
Sadly. some DAR's are strictly in it for the money....no real inspection of the airplane, just the paperwork, $400 and they're gone.
I've seen it at my airport!
Best,
Uuuuuu, Yeah, trying to restore this would cost more than a new build probably. Easier to start fresh than work the repairs.
Lots of work
Here's a photo to give you an idea of what's required to repair a botched installation of these brackets:
The side skins, corner brackets and all 4 lower longerons all have to be replaced to get rid of the bad holes.
Since I was also overhauling the engine, I took the opportunity to replace the firewall, engine mount (long legs now instead of the original short legs), and cowling.
The finished bracket installation looks like this when the gussets are incorporated:
Personally, I thought this was an enjoyable building challenge, but I needed the repair experience to support my long-term warbird aspirations. It took tons of time, though.
Cheers,
Matthew
Here's a photo to give you an idea of what's required to repair a botched installation of these brackets:
The side skins, corner brackets and all 4 lower longerons all have to be replaced to get rid of the bad holes.
Since I was also overhauling the engine, I took the opportunity to replace the firewall, engine mount (long legs now instead of the original short legs), and cowling.
The finished bracket installation looks like this when the gussets are incorporated:
Personally, I thought this was an enjoyable building challenge, but I needed the repair experience to support my long-term warbird aspirations. It took tons of time, though.
Cheers,
Matthew
MauiLvrs
Well Known Member
I feel better about the way ours got botches by a previous builder.
At least he only had one set of holes through the longeron and those holes were clean and re-usable.
