After finding cracks on my 4, I think you'd better take a look at what I found on further investigation! http://www.Jedtek.biz OR scroll down the page to find the photos in a new post.
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Van's Air Force
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RV-4 Safety Issue
- Thread starter Jedtek
- Start date
Kyle Boatright
Well Known Member
The link doesn't work for me. If you don't mind, why don't you post at least a brief description of the problem in this forum. That way it'll be saved for posterity even if your website goes bye-bye.
David-aviator
Well Known Member
A hangar neighbor had the motor mounts crack badly at the firewall, especially the top ones, two years ago. He was very lucky the engine did not separate in flight as the top bolts and brackes had pulled away from the firewall about a half inch. I asked him how many G's he'd been pulling and he said five, but only one time.
I am not that familiar with the -4 but do believe Van's is aware of the problem and has issued a service bulletin on the subject. I wouldn't yank and bank any 4 unless this matter is resolved as to when the airplane was built and whether the corners have been beefed up.
Steve Sampson
Well Known Member
There are, I believe, 3 versions of the steel firewall corner parts, with the heaiest duty ones introduced in the mid '90s. I have put the information I managed to assemble here. Scroll down to point 3.
If the parts in your pictures are from '87 I think they are of a thinner grade of steel than the later ones. The earliest part is (I think) a different shape.
I have never found an SB from VANS but I am sure they can help.
If the parts in your pictures are from '87 I think they are of a thinner grade of steel than the later ones. The earliest part is (I think) a different shape.
I have never found an SB from VANS but I am sure they can help.
Common issue....
This is a well known issue and is a condition inspection item. I wish I could see the pictures to get an idea of how "bad" the cracks are but can't.
There is no SB as such. However, the new parts are a bit thicker.
It would be great if somebody had a mod that would insure this issue would not re-appear. But I haven't seen anything yet........
John
This is a well known issue and is a condition inspection item. I wish I could see the pictures to get an idea of how "bad" the cracks are but can't.
There is no SB as such. However, the new parts are a bit thicker.
It would be great if somebody had a mod that would insure this issue would not re-appear. But I haven't seen anything yet........
John
It's been a while since I built my firewall, so forgive my lack of details, but I'm pretty sure there is a spacer that goes between the weldments and the firewall. It's there to fill the gap created by the aluminum firewall frame. Omitting this part could certainly make the problem worse and is something that buyers of completed aircraft should check for.
RV-4 Safety Issue UPDATE!
I'm sorry about the earlier post and unreliable website. I had far more hits than I ever expected and we went over our allowed bandwidth so it didn't want to play anymore!
After finding small cracks on the lower engine mounting support brackets in the footwells of my 1987 RV-4, I looked at the top mounts (Which were hidden by the front stowage box),and found this! There were no tell tale signs on the firewall other than a few very small cracks around the lower flush rivets. I am the third owner,the airframe has 766 hours and had no damage history.
Van's just tell me to fit the new thicker mountings available.
This is the lower firewall. These are the only visible cracks.
Lower Left
Lower Right
Upper Right
Upper Left
I'm sorry about the earlier post and unreliable website. I had far more hits than I ever expected and we went over our allowed bandwidth so it didn't want to play anymore!
After finding small cracks on the lower engine mounting support brackets in the footwells of my 1987 RV-4, I looked at the top mounts (Which were hidden by the front stowage box),and found this! There were no tell tale signs on the firewall other than a few very small cracks around the lower flush rivets. I am the third owner,the airframe has 766 hours and had no damage history.
Van's just tell me to fit the new thicker mountings available.
This is the lower firewall. These are the only visible cracks.
Lower Left
Lower Right
Upper Right
Upper Left
UPDATE 2!
This is what I received from Van's:
This was documented in the RVator in 1988. I have attached a reprint of
that article. This was not a mandatory change and it was determined that
most of the failures occurred from use on rough strips and/or from hard
landings. Normal inspections of this area are also required. Replacement of
the brackets was optional. WD-403 & WD-404 Attachment Arm thickness
was increased from .050" to .065".
This is what I received from Van's:
This was documented in the RVator in 1988. I have attached a reprint of
that article. This was not a mandatory change and it was determined that
most of the failures occurred from use on rough strips and/or from hard
landings. Normal inspections of this area are also required. Replacement of
the brackets was optional. WD-403 & WD-404 Attachment Arm thickness
was increased from .050" to .065".
brackets
Jed,,,so yea, bout ten years ago, the A&I found the same cracks on my 4 as you now have found on yours. At the time, mine was some ten years old with about 750 hours, a few hard landings and no grass. Van's said for $160, I could purchase the new and improved set of four brackets. They are indeed thicker and of an improved design. So I stacked two bales of straw under each wing and off came everything forward of the firewall. I drilled out the old and replaced with the new albeit adding a gusset in the horizontal plane to each side where the top longeron meets the angle that is on the top backside of the firewall. With ten years and some 600 hours since, there have been no more problems.
Christopher Dahl
#26
flyin n grinin for 20 years
Jed,,,so yea, bout ten years ago, the A&I found the same cracks on my 4 as you now have found on yours. At the time, mine was some ten years old with about 750 hours, a few hard landings and no grass. Van's said for $160, I could purchase the new and improved set of four brackets. They are indeed thicker and of an improved design. So I stacked two bales of straw under each wing and off came everything forward of the firewall. I drilled out the old and replaced with the new albeit adding a gusset in the horizontal plane to each side where the top longeron meets the angle that is on the top backside of the firewall. With ten years and some 600 hours since, there have been no more problems.
Christopher Dahl
#26
flyin n grinin for 20 years
RV-4 Safety Issue UPDATE
Well, I managed to get everything disconnected a few days ago and am today going to remove the engine and framework. Van's tell me I need the drawings to make this repair but they want $100 for them! I was wondering if anyone could possible send me a copy of the repair area? I'm not sure whether I need the updated construction manual page too? This is not going to be fun I'm sure but the alternative would have been far less fun and I thank my lucky stars for finding the failures just in time. I'll try to keep a photo record of my progress so it anyone needs them in the future, they will be available.
Thanks for all your input to this.
Well, I managed to get everything disconnected a few days ago and am today going to remove the engine and framework. Van's tell me I need the drawings to make this repair but they want $100 for them! I was wondering if anyone could possible send me a copy of the repair area? I'm not sure whether I need the updated construction manual page too? This is not going to be fun I'm sure but the alternative would have been far less fun and I thank my lucky stars for finding the failures just in time. I'll try to keep a photo record of my progress so it anyone needs them in the future, they will be available.
Thanks for all your input to this.
smokyray
Well Known Member
Cracked up...
Jed,
The lower firewall cracks in the SS are fairly common on RV4's and not a show stopper (I have looked at ALOT of them). However comma, the support weldment cracks are. You have the early firewall supports which were way too thin. I built custom (very thick) ones when I built my -4 back in 95' and never had a problem.
There is hope, you can change them out with alot of drilling and riveting which you have obviously started. I used countersunk bolts through the fwd fuselage skin for the brackets with .040 doublers. My Rocket has .050 doublers along with railroad size mount brackets!
I can send you my drawings via FAX or I'll try to scan them and post here.
See Ya!
Smokey
HR2
Jed,
The lower firewall cracks in the SS are fairly common on RV4's and not a show stopper (I have looked at ALOT of them). However comma, the support weldment cracks are. You have the early firewall supports which were way too thin. I built custom (very thick) ones when I built my -4 back in 95' and never had a problem.
There is hope, you can change them out with alot of drilling and riveting which you have obviously started. I used countersunk bolts through the fwd fuselage skin for the brackets with .040 doublers. My Rocket has .050 doublers along with railroad size mount brackets!
I can send you my drawings via FAX or I'll try to scan them and post here.
See Ya!
Smokey
HR2
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Smokey! Thank you. I'd really like to see the drawings. I have however, got the new supports from Vans and am in the final stages of fitting them. It is a MAJOR job as a retro fit, the drilling of the new items is vital. I have spent four full days so far to get to the riveting stage. It's a job that takes some time but I am so fortunate to have found the problem in the first place! John, take a good look at the top mounts, mine were considerably worse than the lower ones.
RE: tops are ok....
John. You may be okay then. Apparently, the tops don't seem to be so much of a problem. My upper brackets were actually broken about the same as the lower ones but because of the weight of the engine, the cracks looked larger. It is quite an involved job to do these brackets. You have to take off the undercarriage/engine combination to do any of the four brackets, so I think it would be a good idea to do them all together. I have taken photos while doing the job so if I (or the photos) can be of any help, just let me know. I feel a lot happier knowing I have stronger mounts up front!
John. You may be okay then. Apparently, the tops don't seem to be so much of a problem. My upper brackets were actually broken about the same as the lower ones but because of the weight of the engine, the cracks looked larger. It is quite an involved job to do these brackets. You have to take off the undercarriage/engine combination to do any of the four brackets, so I think it would be a good idea to do them all together. I have taken photos while doing the job so if I (or the photos) can be of any help, just let me know. I feel a lot happier knowing I have stronger mounts up front!
Need a plan...
I'm going to do my next oil change over at the shop and my A&P and I will start our plan for the brackets. Assuming we only do one......
It sounds like this:
1. support engine from hoist wings with jacks/stands
2. unbolt engine mount bolts
3. slide engine forward 6" or so
3. drill out rivets for bracket
4. remove old bracket
5. install new bracket match drill using old holes
6. rivet/bolt new bracket into place
7. Bolt engine back up, leaving out the 1 bolt for the new
bracket.
8. Use a center drill or bushing in the engine mount and
match drill into the new bracket.
9. Intall bolt in new bracket
Nothing to it
It must be a bear to buck the rivets inside the fuse ? Did you consider removing the belly skin for access ?
Any great tips to make it all "easy".
Thanks
John
I'm going to do my next oil change over at the shop and my A&P and I will start our plan for the brackets. Assuming we only do one......
It sounds like this:
1. support engine from hoist wings with jacks/stands
2. unbolt engine mount bolts
3. slide engine forward 6" or so
3. drill out rivets for bracket
4. remove old bracket
5. install new bracket match drill using old holes
6. rivet/bolt new bracket into place
7. Bolt engine back up, leaving out the 1 bolt for the new
bracket.
8. Use a center drill or bushing in the engine mount and
match drill into the new bracket.
9. Intall bolt in new bracket
Nothing to it
It must be a bear to buck the rivets inside the fuse ? Did you consider removing the belly skin for access ?
Any great tips to make it all "easy".
Thanks
John
Easy...
Yes, everything is easy on the internet. I'd be more than happy to take any advice/pictures you might have. Maybe we can build up a knowledge base for this operation.
Thanks
John [email protected]
Yes, everything is easy on the internet
. I'd be more than happy to take any advice/pictures you might have. Maybe we can build up a knowledge base for this operation.Thanks
John [email protected]
