RV-12A Engine Mount Cracks

[7StarsAero]

I have two factory built RV12s the the 912ULS engine. One engine has about 900 hours on it. The other has close to 1600. On the last inspection I found a crack on the 900 hour engine mount. It was on the left side tube just below the upper engine support arm. Its difficult to tell from the pictures, but the crack wrapped around the tube about 230 degrees and travels back and up around the tube, with the lowest point of the crack being on the front side of the mount. Now, I have found another crack on the higher time engine mount. It was spotted while the bottom cowling was off and has formed within the last 50 hours (this mount was checked 50 hours ago in this exact spot by myself and a second mechanic). This crack is in a similar area, located on the left side tube, but on the bottom engine support arm.

I have seen one other similar crack on this forum from sometime last year. I am wondering if anyone else has experienced cracks like this. Having two aircraft at vastly different engine times experience similar cracks within 100 hours of each other is concerning. If anyone has any suggestions or experience with these cracks, I would appreciate it. I am concerned this is only a symptom of a bigger problem and not the actual issue. That being said, both of these cracks are near heat effected areas of welds, so it could just be poor heat treatment.

Declan

 

[seagull]

Can you share pics from farther back maybe with an arrow or circle to help us know exactly where you are finding these?

 

[7StarsAero]

Can you share pics from farther back maybe with an arrow or circle to help us know exactly where you are finding these?

This is the engine mount from the first crack on the 900 hour engine. I have yet to remove the second mount, but I have noted where it cracked with an arrow.

 

[Piper J3]

I have reported on cracks in two different 912ULS RV-12 engine mounts. The mount on my airplane had a cracked tube at lower left engine attach fitting. It was repaired with 4140 welded over-sleave. The second engine mount had crack in rear ring on right side near oil tank. It also was repaired with 4140 welded over-sleave. I know of one other RV-12 mount that had same crack on rear ring right side....

 

[rk2436]

Was your propeller ever balanced? Carbs kept in sync too?

 

[Piper J3]

Was your propeller ever balanced? Carbs kept in sync too?

Yes, both airplanes had dynamically balanced props and carbs well synched...

 

[seagull]

Piper J3,
Do I remember your -12 had a landing gear mounting crack, and you land mostly off asphalt? Could that be a contributing factors to the motor mount cracks? Or am I thinking of the wrong person?

 

[Piper J3]

Piper J3,
Do I remember your -12 had a landing gear mounting crack, and you land mostly off asphalt? Could that be a contributing factors to the motor mount cracks? Or am I thinking of the wrong person?

You remember correctly... However, my friend's RV-12 (TT500) flies gently from asphalt and he had the crack in the rear ring portion of the engine mount.

 

[whity1231$]

Will unfortunately as I was just starting my condition inspection I have also found a crack in my motor mount. 2011 with 1057 hrs. Gearbox rebuilt by Lockwood, prop always balanced and carbs. always synced. Crack was on the right (passenger side) side main frame tube just above the where the small tube is welded that goes to the engine. I guess having gusseted and welded is the only option. New one was listed last at about $1,900 and who knows when available. I’ve been making sure to really inspect after all the SB’s (front leg, stand off and Piper J3 and others post )Now to get it all off and more importantly to find someone qualified to weld it. Any advice appreciated.

 

[CTCole]

The engine mount part number, WD-1220, is the same for the ULS and iS engines. Does anyone know if there were changes made to prevent cracking, e.g. different materials or heat treatment? Have more recent mounts also cracked?

 

[Russ McCutcheon]

Will unfortunately as I was just starting my condition inspection I have also found a crack in my motor mount. 2011 with 1057 hrs. Gearbox rebuilt by Lockwood, prop always balanced and carbs. always synced. Crack was on the right (passenger side) side main frame tube just above the where the small tube is welded that goes to the engine. I guess having gusseted and welded is the only option. New one was listed last at about $1,900 and who knows when available. I’ve been making sure to really inspect after all the SB’s (front leg, stand off and Piper J3 and others post )Now to get it all off and more importantly to find someone qualified to weld it. Any advice appreciated.

It looks like you're not too far from me, bring it up and spend a couple hours and I'll send you home with it repaired.

 

[Piper J3]

Will unfortunately as I was just starting my condition inspection I have also found a crack in my motor mount. 2011 with 1057 hrs. Gearbox rebuilt by Lockwood, prop always balanced and carbs. always synced. Crack was on the right (passenger side) side main frame tube just above the where the small tube is welded that goes to the engine. I guess having gusseted and welded is the only option. New one was listed last at about $1,900 and who knows when available. I’ve been making sure to really inspect after all the SB’s (front leg, stand off and Piper J3 and others post )Now to get it all off and more importantly to find someone qualified to weld it. Any advice appreciated.

It looks like crack is sufficiently in the straight section of tube, so a split over-sleeve should work. Need correct filler rod and welding technique to relief stress. Very doable. Look at photos above in post #4. Russ McCutcheon is nice guy...

 

[Rdog420]

I have two factory built RV12s the the 912ULS engine. One engine has about 900 hours on it. The other has close to 1600. On the last inspection I found a crack on the 900 hour engine mount. It was on the left side tube just below the upper engine support arm. Its difficult to tell from the pictures, but the crack wrapped around the tube about 230 degrees and travels back and up around the tube, with the lowest point of the crack being on the front side of the mount. Now, I have found another crack on the higher time engine mount. It was spotted while the bottom cowling was off and has formed within the last 50 hours (this mount was checked 50 hours ago in this exact spot by myself and a second mechanic). This crack is in a similar area, located on the left side tube, but on the bottom engine support arm.

I have seen one other similar crack on this forum from sometime last year. I am wondering if anyone else has experienced cracks like this. Having two aircraft at vastly different engine times experience similar cracks within 100 hours of each other is concerning. If anyone has any suggestions or experience with these cracks, I would appreciate it. I am concerned this is only a symptom of a bigger problem and not the actual issue. That being said, both of these cracks are near heat effected areas of welds, so it could just be poor heat treatment.

Declan

good catch on inspection. ouch

 

[whity1231$]

good catch on inspection. ouch

It looks like you're not too far from me, bring it up and spend a couple hours and I'll send you home with it repaired.

Thanks for the invite Russ and I’ve seen many good compliments on your work. The original owner of Senergy gave me a name of a guy down here that they used and if doesn’t line up I will contact you. Van’s won’t have new ones until after February??? And they haven’t changed them any (like heavier wall thickness or ?), still sending them out on all the 12’s. Since it seems the mounts have cracked in many different locations, but always above the weld for the small tube,is it likely to then crack above a different small tube? Jim probably has the most hours after a repair and i guess no new cracks at a different small tube location? I guess I better start disconnecting everything and pull the engine! Fun, fun!

 

[csmith3603]

I have two factory built RV12s the the 912ULS engine. One engine has about 900 hours on it. The other has close to 1600. On the last inspection I found a crack on the 900 hour engine mount. It was on the left side tube just below the upper engine support arm. Its difficult to tell from the pictures, but the crack wrapped around the tube about 230 degrees and travels back and up around the tube, with the lowest point of the crack being on the front side of the mount. Now, I have found another crack on the higher time engine mount. It was spotted while the bottom cowling was off and has formed within the last 50 hours (this mount was checked 50 hours ago in this exact spot by myself and a second mechanic). This crack is in a similar area, located on the left side tube, but on the bottom engine support arm.

I have seen one other similar crack on this forum from sometime last year. I am wondering if anyone else has experienced cracks like this. Having two aircraft at vastly different engine times experience similar cracks within 100 hours of each other is concerning. If anyone has any suggestions or experience with these cracks, I would appreciate it. I am concerned this is only a symptom of a bigger problem and not the actual issue. That being said, both of these cracks are near heat effected areas of welds, so it could just be poor heat treatment.

Declan

Howdy there; So you replaced them with new van's aircraft engine mount parts.

With a RV12iS aircraft, you should check engine mounts every anual for cracks!

 

[Piper J3]

Follow-up to post #4 above... Photos are finished weld repair.

 

[seagull]

I’m on the list, 1805 hours, she has been treated like a queen, but still. Looks like the only option is to repair it since none are available from Van’s.

 

[pparke]

Well, given this little bit of knowledge about the mounts should I be concerned about purchasing an RV12. I was interested, but now not to keen on it. Seems like low time airplanes to have cracking on the mounts. What about the other mounts from Vans do they have the same problems.

 

[dadjokes]

Those of you with cracks. Were all these cracks with the stock 2 bladed prop? IMHO, I suspect that prop is the cause of many of the cracking issues on the 12's Both 12's that I've owned were changed to a Duc 3 bladed very early on with significantly smoother operation. Has anyone ever had a crack like this with a 3 bladed prop?

 

[whity1231$]

The airplane was designed for the two blade propeller. So my thinking is if the airplane in maintained properly ( balanced carbs and prop, and prop angles the same, and gearbox serviced ) the motor mount should be made to not crack in the various hours and different locations on the mount.

 

[N8DAV8R]

Those of you with cracks. Were all these cracks with the stock 2 bladed prop? IMHO, I suspect that prop is the cause of many of the cracking issues on the 12's Both 12's that I've owned were changed to a Duc 3 bladed very early on with significantly smoother operation. Has anyone ever had a crack like this with a 3 bladed prop?

I am working one with a cracked standoff with a 3 blade prop.

 

[whity1231$]

Is that the newer standoff that has thicker wall tubing or the pre- SB one?

 

[N8DAV8R]

Is that the newer standoff that has thicker wall tubing or the pre- SB one?

I do not have the original packing list, but the dates would strongly support that this is the pre-sb standoff. I'm very confident in that.

The only reason I say that with room for any doubt, is that I have also now looked closely at this scenario for my own RV-12is. My packing list says that I have a -1 version, which is also supported by the shipping date relative to the SB. The issue is that I have obtained a replacement -1 standoff and it has a permanent metal "Do Not Remove" label that identifies it as that. The one on my airplane does not have that label. I am left to conclude that the "Do Not Remove" tag is a change that came after some number of -1 versions were shipped. It seems that not all -1 will be labeled as such, leaving builders/maintainers to draw some conclusions on their own.

 

[seagull]

Following FAA AC 43.13-1B I repaired the crack, which was about 3/4 around added a splice of 4130 over the top.

 

[whity1231$]

A follow up on the repair of my engine mount which probably won’t help anyone unless they have the mount off the engine. The aircraft weld shop that I had my mount repaired at used some penetrating dye to check a couple very small rust spots at the edge of the weld on the small mount tubes and found that they also had small cracks starting. He couldn’t see them even with the coating removed, but the dye showed them. Repaired and off to be powered coated. I debated on whether to paint or coat, but he said that coating would make it easier to spot any new cracks. Only cost $70 to coat. The pictures are before cleaning right after welding.

 

[Piper J3]

Looks like they put a lot of heat into that weld... Did they cool it slowly with thermal blanket? Did they make a jig for holding alignment to prevent distortion from heat?

 

[seagull]

As Piper J3 said a jig is important to hold the engine side of the mount in alignment. If it gets distorted during the welding process, then torqued to the engine it will be under stress and likely to crack again. This is what I did.

 

[whity1231$]

This person builds airframes and mounts for competitive Pitts customers, so I’m sure he did all you suggested. My main point of the post is you might have some small cracks on the small tube that might not be visible without using penetrating dye???

 

[Piper J3]

As Piper J3 said a jig is important to hold the engine side of the mount in alignment. If it gets distorted during the welding process, then torqued to the engine it will be under stress and likely to crack again. This is what I did.
View attachment 107446

The way things are going... you might want to keep that weld fixture handy

 

[Russ McCutcheon]

RV-12 engine mount standoff I just repaired.

 

[pparke]

I asked Hans at Vans about the cracking, He replied I haven’t seen widespread cracking, but I have seen a couple of airplanes with some cracking. There is not an upgrade at this time but was going to ask their engineers. This seems pretty significant to me that this could be an accident waiting to happen. Is this normal with home built aircraft.

 

[docjjrmd]

I asked Hans at Vans about the cracking, He replied I haven’t seen widespread cracking, but I have seen a couple of airplanes with some cracking. There is not an upgrade at this time but was going to ask their engineers. This seems pretty significant to me that this could be an accident waiting to happen. Is this normal with home built aircraft.

Part of this is a statistical issue. Cracks will occur in all planes, certified or EAB. It is unreasonable to expect 100% no cracking, its inherent risk that we try to engineer to absolute minimum, but will never be zero. For Van's aircraft with 11,000 plus flying and for the RV12 in particular with 1000 or so flying the question becomes what number becomes statistically significant? So far as I know, all cracks have been found on routine inspection (nice way of saying no engines have fallen off) and I suspect we have listed here a majority of RV-12s with the problem. Eventually, the question will be what is the cost to force a replacement of the mounts, or cost of repair kit. across the fleet. What would be the howls for folks with hundreds or thousands of hours on their plane with no cracks who would be forced to pay large $ to replace or repair what they see as a non-issue? Flying is not and will never be risk free. Reporting of cracks found, how they were found, and repaired, adds to our knowledge base and makes us all safer just by having the knowledge in hand. Keep looking for all issues, but just because a failure is found, does not mean it applies to all. What it does do is make everybody better looking for the same potential failure.

Welcome to VAF by the way!

 

[whity1231$]

As one of the “few” ( actually many just in this thread) that has actually found cracks in their mount and still in the process of having to disconnect every thing to remove the engine to have my mount repaired because Van’s doesn’t have any mounts in stock, I would gladly have paid have put a new one in. As they did with the standoff mount S.B., they could just have new mounts made with a heavier wall tubing. Not much room to do much changing off the shape off it.
Show me folk’s with as you said with hundreds or thousands of hours on their RV12 that would not be glad to put a new and maybe improved mount on their airplane when a crack was found instead of having to put a old repaired one on. The owners of S-ULS RV 12’s would be the only one’s that would have to replace, depending on how the SB was issued. Right now, if they are using their 12 commercially as in a flight school, I bet they would be happy to put a new, improved and in stock mount back on instead of having the plane grounded! If I was I flight school I would be more concerned that none are in stock to get my airplane back working.
Apparently Van’s has the same mount available enough to put on the factory S-RV12’s.
I understand that they are very busy trying to get the RV 15 kits out the door, but their other RV’s including their “certified “ 12 needs replacement parts also.

 

[Ramblin' Wreck]

After many years of lurking without actually posting, this isn’t the first post I had hoped for, but add me to the list of -12 owners with an opportunity for some “learning and patience development” in the near future. After reading this thread, I decided it was a good time to do a thorough inspection. Didn’t have to look too long before I saw this at the lower right attach point. I was hoping it was just in the powder coat, but it’s definitely cracked through and visible on the inside.

Anybody received an estimated get well date for new mounts from the mothership? I’m going to email them this evening and cross my fingers, since I doubt this one is repairable.

On the bright side, maybe the lead time will give me an excuse to order a -15 wing kit .

-Josh

 

[docjjrmd]

As one of the “few” ( actually many just in this thread) that has actually found cracks in their mount and still in the process of having to disconnect every thing to remove the engine to have my mount repaired because Van’s doesn’t have any mounts in stock, I would gladly have paid have put a new one in. As they did with the standoff mount S.B., they could just have new mounts made with a heavier wall tubing. Not much room to do much changing off the shape off it.
Show me folk’s with as you said with hundreds or thousands of hours on their RV12 that would not be glad to put a new and maybe improved mount on their airplane when a crack was found instead of having to put a old repaired one on. The owners of S-ULS RV 12’s would be the only one’s that would have to replace, depending on how the SB was issued. Right now, if they are using their 12 commercially as in a flight school, I bet they would be happy to put a new, improved and in stock mount back on instead of having the plane grounded! If I was I flight school I would be more concerned that none are in stock to get my airplane back working.
Apparently Van’s has the same mount available enough to put on the factory S-RV12’s.
I understand that they are very busy trying to get the RV 15 kits out the door, but their other RV’s including their “certified “ 12 needs replacement parts also.

Please don't misinterpret the meaning of my post. Folks with cracks certainly would be served better by having a beefed up brand new from the factory mount. I suspect these are 3rd party produced.

 

[jsalley]

After many years of lurking without actually posting, this isn’t the first post I had hoped for, but add me to the list of -12 owners with an opportunity for some “learning and patience development” in the near future. After reading this thread, I decided it was a good time to do a thorough inspection. Didn’t have to look too long before I saw this at the lower right attach point. I was hoping it was just in the powder coat, but it’s definitely cracked through and visible on the inside.

Anybody received an estimated get well date for new mounts from the mothership? I’m going to email them this evening and cross my fingers, since I doubt this one is repairable.

On the bright side, maybe the lead time will give me an excuse to order a -15 wing kit .

Hey Josh - Welcome! Which attach point is that (L/R, front/rear)?

 

[Ramblin' Wreck]

Hey Josh - Welcome! Which attach point is that (L/R, front/rear)?

Thanks! It’s the R front/lower attach point.

 

[CTCole]

The mounts that are cracking are a Rotax-produced part, #886565. The engine mount standoff also mentioned in some posts is supplied by Van's.

 

[whity1231$]

That is a wrong statement. When I called Van’s support to see if they could give me a estimate of when the mounts would be available and if they were still the same mounts as original, I was told that for the RV12 that Van’s builds those in-house and that they had not changed them but had discussed it. Also, even the originals restocking was estimated at 60 days???. Go to Rotax’s web and the Rotax mounts don’t even look anything like the RV 12’s.

 

[bbaggerman]

Go to Rotax’s web and the Rotax mounts don’t even look anything like the RV 12’s.

Maybe not the same but to say they don't look anything alike is a bit of a stretch.

 

[CTCole]

Whity1231$, thanks for the correction. Looks like Van's has some re-engineering to do.

 

[Russ McCutcheon]

As one of the “few” ( actually many just in this thread) that has actually found cracks in their mount and still in the process of having to disconnect every thing to remove the engine to have my mount repaired because Van’s doesn’t have any mounts in stock, I would gladly have paid have put a new one in. As they did with the standoff mount S.B., they could just have new mounts made with a heavier wall tubing. Not much room to do much changing off the shape off it.
Show me folk’s with as you said with hundreds or thousands of hours on their RV12 that would not be glad to put a new and maybe improved mount on their airplane when a crack was found instead of having to put a old repaired one on. The owners of S-ULS RV 12’s would be the only one’s that would have to replace, depending on how the SB was issued. Right now, if they are using their 12 commercially as in a flight school, I bet they would be happy to put a new, improved and in stock mount back on instead of having the plane grounded! If I was I flight school I would be more concerned that none are in stock to get my airplane back working.
Apparently Van’s has the same mount available enough to put on the factory S-RV12’s.
I understand that they are very busy trying to get the RV 15 kits out the door, but their other RV’s including their “certified “ 12 needs replacement parts also.

This is one big thing that has always rubbed me wrong about Van's for the 35 years of vending weldments to them (now retired) and the 21 years owning and flying an RV-4. I'll quote a past ranking member of Van's staff,

"We can't let Joe Smith who owns a flying airplane jump the line ahead of the guys waiting for their kit to get an engine mount to replace one that was damaged"

Van's only seems to want to be a kit manufacture and doesn't or hasn't in the past wanted with any urgency to support the fleet. I think I saw someplace in this thread that it was estimated to be 60 day wait for this mount, that's not to bad. I have been called at least 20 times in the past 5-7 years asking what the problem was getting an engine mount, guys being quoted 18 to 24 months to get a mount for an RV-4 as well as some of the other models, in my eyes, that's not support but more like please go away. In all fairness maybe this has changed but from some more recent calls I've received, I kind of doubt it has.

 

[Ramblin' Wreck]

This is one big thing that has always rubbed me wrong about Van's for the 35 years of vending weldments to them (now retired) and the 21 years owning and flying an RV-4. I'll quote a past ranking member of Van's staff,

"We can't let Joe Smith who owns a flying airplane jump the line ahead of the guys waiting for their kit to get an engine mount to replace one that was damaged"

Van's only seems to want to be a kit manufacture and doesn't or hasn't in the past wanted with any urgency to support the fleet. I think I saw someplace in this thread that it was estimated to be 60 day wait for this mount, that's not to bad. I have been called at least 20 times in the past 5-7 years asking what the problem was getting an engine mount, guys being quoted 18 to 24 months to get a mount for an RV-4 as well as some of the other models, in my eyes, that's not support but more like please go away. In all fairness maybe this has changed but from some more recent calls I've received, I kind of doubt it has.

I called today and ordered a replacement mount for my -12. The current lead time is 60 days. They are expecting new stock next month, so fingers crossed mine ships out sooner than 60 days. 60 days is like 20 lost flying opportunities for me, but it is better than I originally feared it would be.

 

[whity1231$]

I was told 60 days three weeks ago? ? I assume it is the original mount that we all have been having break? I haven’t got my welded mount back from powder coating yet. If I really thought they would have some next month, I would be tempted to gamble and wait. Hopefully get another 1000 hours for $1;900.00??? Not much of a gambler, so decisions decisions

 

[Ramblin' Wreck]

I was told 60 days three weeks ago? ? I assume it is the original mount that we all have been having break? I haven’t got my welded mount back from powder coating yet. If I really thought they would have some next month, I would be tempted to gamble and wait. Hopefully get another 1000 hours for $1;900.00??? Not much of a gambler, so decisions decisions

Same original mount. I'll keep you posted when I get a shipping notification. I sure hope I get 1000 hours out of this one.

 

[snowsam]

I called today and ordered a replacement mount for my -12. The current lead time is 60 days. They are expecting new stock next month, so fingers crossed mine ships out sooner than 60 days. 60 days is like 20 lost flying opportunities for me, but it is better than I originally feared it would be.

They told me today that Syspro showed them to be in stock. Hmmm.

 

[Piper J3]

My engine mount RV-12 SN 120058 does not have strenthening flanges at engine attach points, so fabrication has been updated somewhere along the line... See photo red arrow

 

[whity1231$]

Good eye. My mount doesn’t either. Didn’t stop Rambling Wreck’s from cracking in the attachment??

 

[seagull]

Mine had the gussets, still cracked. Back on the plane, today was the first flights.

 

[Piper J3]

I might be wrong, but I think I've seen a mount on newer 12 that had gussets welded on inside surface of engine attach fittings. This would allow easier visual inspection of the tubing with the gusset welded on the back side. So, possibly a 3rd iteration of the RV-12 engine mount...