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RV-12: Engine Mounting Cap Screws Inspection

There are two main issues:

ISSUE 1. Notify RV-12 owners that the engine mount bolts are loosening and falling out.
This is a moral issue. Most of us would like to see RV-12 owners immediately notified to check the bolts. Until then, bolts are slowly vibrating out. RV-12 owners who have had engine bolts loosen can warn others by contacting aviation magazines and the EAA and the FAA. If the magazine editors received letters from several builders, they might write an article or publish the "letters to editors". The word will be spread.

ISSUE 2. Preventing the bolts from loosening.
Split ring lock washers do not work as evidenced by laboratory experiments and RV-12 field experience. It would be nice if we received official guidance on this issue. But manufacturer's do not know any more about solving this problem than the builders. Regardless of engineering theory, it is what works in the field that counts. Rotax mechanics have been using blue Loctite with success, even though they might be reluctant to officially recommend it due to liability concerns. And using blue Loctite seems to be the consensus among RV-12 builders. Nothing is perfect and Loctite has disadvantages. It has temperature limits, should not be disturbed by periodic torque checks, and makes removing bolts difficult. But it works and will keep the bolts from loosening. Another possible solution is using Nord-Lock washers. They work well holding the brake and propeller bolts. Nord-Lock washers are not affected by normal engine block temperatures; they can be periodically checked for torque; and the bolts can be easily removed with a wrench. But regardless of theory, they need to be proven in the field.

We can complain and try to influence others but we can not control what they do. What we can do is spread the word to other builders, perhaps with the help of national and international media. And we can ensure that our own engine mounting bolts do not come loose.
Joe

Joe,

You have it nailed. Number 2 is easier than number 1. I, for one and others I know of are testing the Nordlock theory. Others, Loctite. I expected us to be the beta testers because as you say, "we are the field" and that is the way experimental aircraft are made safer. Your number 1 is very puzzling because it could save lives. We can only contact those we know of. Others have much larger resources to get the message out. And when you realize that many of them are readers and contributors to this forum its stunning. The EAA alone participates in this forum and yet ignores this issue. Are they all waiting for Van's to bless their comments? This is experimental, grass roots aviation, not corporate politics. Of course if you think about it, safety issues only become issues following fatalities. Shouldn't be much of a wait. Thanks for your personal concerns.
 
Bolts

I have been thinking about this problem really hard of late. I have on hand the Nord Lock washers and both blue and red Loc Tite, and debating which to use.

Fortunately the real harm done so far is only to Van's reputation. I have been a customer since 1993 (I think it was) when I began building an RV6A, and now the RV-12, and in all that time I genuinely believed Van's organization was an honest and forthright organization. This current departure from their highly regarded (and deserved) reputation is really strange. Unless something is done promptly to repair this self-inflected harm it is going to take a long time to undo the damage.

Its only my opinion, and just like belly buttons, we all have one.
 
Hey John - -

I would NOT recommend RED Loctite. It takes lots of heat to get them out, and that may create other issues. I'd again suggest BLUE, and check them often as you feel comfortable. After this morning, I am now at 209.9 hours. They seem to be fine. As I have also said, I have around 100 hours on them, and they have not moved. If we find the nord-lock washers to be good also, fine, use BOTH. You could take them out if you want/need to, but could fly with confidence they are not going to fall out.

John Bender
 
Notify Email From Vans!

I just received a Notify email from Vans containing the info about the mounting bolts. So now the info is going out to all owners.:D
 
I have learned that

In life, when common sense and practicality 'appear' to have been left behind, that there is a lawyer is involved.
 
I just received a Notify email from Vans containing the info about the mounting bolts. So now the info is going out to all owners.:D

It's good that they have finally notified owners by email, but you have to wonder why it has taken them nearly two weeks to get around to it. The service notice on Van's website is dated 19 Nov, just two days after Larry G first reported the problem here. I've had great service from Van's ever since I ordered my kit, but this apparent lack of urgency is a puzzle, given the potentially catastrophic consequences of losing these bolts.

Incidentally, they have just issued revision D of page 46-06 in the RV12 section on the website.
 
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Bolts slightly loose at 20 hours

Just finished checking the bolts and modifying the engine shroud on N143WM at 20.1 hours.
All bolts were torqued to 310 in-lb PER THE RV-12 MANUAL at installation. At 20.1 hours all bolts required 10-15 deg of turn to go back to 310 in-lbs. I removed all the bolts, inspected them, coated them with lots of blue Loctite 243, reinstalled them and torqued them to 360 in-lb. All bolts were torque marked so I can see if they've moved at "regular" intervals, whatever "regular" comes to mean. I increased the size of the slot in the shroud so the upper left bolt could be removed. I did not remove the powder coating inside the mount since it hadn't been mentioned at the time and I'm not sure how it can be done with the engine in place.

After removing the lower right bolt it could not be reinstalled until enough pressure was put on ther arm of the mount to flex it down almost 1/16 inch. A friend whose entire career at Wright-Pat says that the problem is due to something in the structure flexing in the right way to set up a resonant frequency-- possible the lower right motor mount arm? That's the only bolt that did not go right back in.

The real problem, and one I'd think the whole LSA community would be VERY concerned about, is that the ONLY structural fasteners in the whole airplane that DO NOT have self-locking nuts, cotter pins, or safety wires are the 4 bolts holding the engine on! Is that ASTM standards??? If so, then I think the first time the FAA finds the engine of an RV-12 a half-mile from the crumpled wreckage, the result will make the CH-601 ruckus look insignificant!

My feeling is that the real solution may be a re-designed motor mount with a way to safety those 4 bolts.


Wayne 120241/N143WM
 
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E-mail notification

Well maybe only to those with an engine, I have only the Empennage kit, no e-mail from them and I know they have it, but it makes sense as I don't have an engine yet.

It's good that they have finally notified owners by email, but you have to wonder why it has taken them nearly two weeks to get around to it. The service notice on Van's website is dated 19 Nov, just two days after Larry G first reported the problem here. I've had great service from Van's ever since I ordered my kit, but this apparent lack of urgency is a puzzle, given the potentially catastrophic consequences of losing these bolts.

Incidentally, they have just issued revision D of page 46-06 in the RV12 section on the website.
 
All Four Capscrews Retorqued to 360 in-lbs

Finished checking all four engine mounting capscrews. At 85 hours, found three of the four slightly loose. Was able to get about 1/8 of a turn on the three. The fourth (one of the lower ones) need not budge at 310 in-lbs.

Van's tells you to use a ball end 8mm allen to get to the upper right capscrew. My drip tray was squarely in-line with the capscrew head and as such I had to remove the right side carb, the right side carb flange and drip tray. The o-ring popped out. It had swelled in diameter. It was not crushed. Could not get it back in the slot. Have another on order from LEAF. $6. Suggest having one on hand if you decide to remove the flange and drip tray. It also could have been my o-ring and how it reacted to alcohol free gasoline.

Felt I would get a better torque, and minimize any capscrew head damage if I was square to the capscrew head and had full allen wrench engagement?? A little more work but not hard and I felt better.

Did all of you guys that have checked the upper right have to REMOVE the drip tray??

The o-ring will be here Tuesday or Wednesday. No real problem as we got 7" of snow in the last 24 hours.
 
Well maybe only to those with an engine, I have only the Empennage kit, no e-mail from them and I know they have it, but it makes sense as I don't have an engine yet.

Same here, Chris. I haven't received an email, but then haven't ordered my engine yet either. I hope that by the time I do, Vans and Rotax will have got their heads together and come up with an official fix.
 
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Finished the "easy three", using Nord-Locs

About 3 weeks ago I found my bottom right was almost out and lost. The bottom left was about 1 turn from tight. I replaced the bottom two bolts dry and clean using the carbon steel Nord-Loc washers and no Lock-Tite. Because I wanted to get on the upper right bolt with a regular allen socket, like Marty I removed the right carb and drip pan. The O-ring was somewhat swollen in diameter. I used a bit of Easy-Turn fuel lube to stick it back into the slot. I will order a couple of spares for future. The upper right mounting bolt took about 30° rotation before the torque wrench clicked at 26 ft-lb. I replace the upper right lock washer using the carbon steel Nord-loc and no Lock-Tite. I torqued all three bolts to 30 ft-lb, dry, per the latest Notice. I ran out of time today and will need another day to do the shroud mod and the upper left bolt.
I am committed now to trying the Nord-Loc washers without Lock-Tite. I really want to be able to put the torque wrench on them when I inspect them. Because the Nord-Locs are unproven by field experience on the engine bolts, I plan to check them at 15 hours. Then 25 then perhaps longer. If the bolts loosen, I will probably remove the Nord-Locs and use Lock-Tite blue 243, like the majority of others. Right now I feel pretty confident the Nord-Locs will work and they are a more elegant solution than glue :rolleyes:.
I did an engine start today to check for leaks because I had done an oil change. The motor was noticeably smoother at idle with all the bolts back in. I had noticed some increased vibration when the motor was cold, and I thought it was due to colder weather. It was due to the loose bolts and so I wanted to mention the obvious; any increase in vibration would be reason to pull the cowls and check things over.

Tony
 
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Someone mentioned earlier that perhaps the bolts coming loose are NOT the problem, only the symptom of another deeper problem with the design of the engine mount itself. It seems to me that if it is flexing enough to loosen bolts, then perhaps it needs a brace somewhere to stiffen it up. If so, that would also shine some light on the slow response so far for a fix. I would submit that even after the bolts are secured, it may be a good thing to keep a close look at the motor mount itself, looking for signs of distress cracking etc...
 
Nord-locs are for application without heat cycles. Why wouldn't you loctite when a 100% of the people using it including myself haven't had any problems?
IMHO not using a ball driver like Van's suggest is a lack of common since. The problem is the powder coat anyway. Get rid of it and you can just use the split ring lock washers.
 
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Nord-Lock washers

Nord-locs are for application without heat cycles.
rschy,
Where did you read that? I am interested in reading the full report and reason behind that.
Thanks,
Joe
 
I am committed now to trying the Nord-Loc washers without Lock-Tite. I really want to be able to put the torque wrench on them when I inspect them. Because the Nord-Locs are unproven by field experience on the engine bolts, I plan to check them at 15 hours. Then 25 then perhaps longer. If the bolts loosen, I will probably remove the Nord-Locs and use Lock-Tite blue 243, like the majority of others. Right now I feel pretty confident the Nord-Locs will work and they are a more elegant solution than glue :rolleyes:.
Tony

Hey Tony,
I also am using Nord-Locs without the glue, only I am not flying yet. Please keep us informed as you accumulate hours. Not having loctite in there, you will be able to check the actual torque values for change! I sure like that idea.
Tom
 
Removing the powder coating from the mating surfaces per Vans new instructions is no problem for those who haven't hung their engine. For the 65 + who are flying, it's another issue. Anybody tried this yet?
 
Mark - good point but -

For those of us that have had loose bolts ( most of us ), the surfaces in question have had time to work off tiny imperfections, and compress the paint to the point it is not that big an issue. If you add plenty of Loctite, and retorque them, I think they will stay put just fine. If in doubt, take one out at the next annual, and clean it and put it back in. If you keep an eye on the torque seal, and if it has stayed put, you have little to worry about. With 'blue' Loctite, you could re-do them every annual if it makes you more comfortable. Check the torque before you remove them just to see if you can detect any changes. I think everyone will find that 'blue' will satisfy this BIG problem. Lets report anything we find as we go along. If something better comes along, fine, but Loctite should give you comfort for now.

John Bender
 
Which came first?

The old saying, "Which came first, the chicken or the egg?" applies to the powder coat. Did the powder coat wear away first and thus loosened the bolts? Or did the bolts loosen first and then the moving parts wore away the powder coat? I suspect the latter. Some builders have NOT removed the powder coat and have used Loctite on the engine mounting bolts and have flown many hours without the bolts coming loose.
I agree with John Bender. Loctite will prevent the bolts from turning. It will be interesting to hear from those who are using Nord-Lock washers after a long test period. Van's service bulletin to remove powder coat and tighten to 30 foot pounds should extend the time before the bolts come out. :D
Joe
 
Nordlocks

As Joe said earlier, the true testing is done in the field, not on a calculator. Like Tony and some others I too am going to use the Nordlocks without the Loctite simply because I think we need to be trying different methods and reporting back for future builders. I have nothing against Loctite, just think we need more than two people taking another path. My plane has 185 hours on it so much should be settled in. We'll see how it goes. Like Tony, I have read nothing in the tons of Nordlock info that relates to heat. Would like to see that. And of course, Rotax (and thereby Vans) will not endorse Loctite (or Nordlocks) and I can understand why. Loctite cannot be retorqued without removal and cleaning. Nordlocks have never been tried period on this engine. Thus goes the experimental aircraft business. As long as we all keep each other up to date on regular check-ups, things should be fine. My only remaining concern is for the poor slobs who build away in their garage and don't have a computer and put their bolts in with those stupid split washers. We all know where that ends up.
 
My only remaining concern is for the poor slobs who build away in their garage and don't have a computer and put their bolts in with those stupid split washers. We all know where that ends up.

Which brings up a question. Does Van's Aircraft consider their notification a MANDATORY change? I would certainly think that would be the case with respect to this flight critical item.

We were told MANY times during the early build process, with the multitude of REVISED plan pages that VAN'S would SPECIFICALLY state to the builder via a notification if a change was considered to be MANDATORY and REWORK is required.
This did occur with a few previous items.

I received two e-mails from Van's. The first was the FF-1207 top cooling shroud modification. The second indicating the capscrew torque should be increased to 30 ft-lbs per the ROTAX documentation, and the powder coating should be removed on the engine mount mating surface. Nowhere a hint that the retorque would most likely cure the problem and the retorque, torque seal and periodic inspection should be sufficient. (My interpretation.)

Nowhere a hint that this change was mandatory. Did I miss an e-mail?

HAS THEIR NOTIFICATION POLICY CHANGED??
 
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Mandatory?

I received the same two emails. I do not think that you missed any. I agree with what you are saying, Marty. For those of us who have their aircraft flying and the test hours flown off, any change by Van's or Rotax is not mandatory for E-LSA or E-AB. We are required to acknowledge the notice and take action as we deem appropriate, not necessarily comply with the instructions in the notice.
Joe
 
Joe, I agree with your conclusion. As I said earlier I have settled on the blue Loctite, 360 in lbs and torque seal with a look at each oil change. Have decided not to go with the Nordloks as at this juncture am satisfied with the success of others using the Loctite.
I have started on my repair and am happy to report that at 43.6 hrs neither of the lower bolts have lost any ground. They still pop the torque wrench at 312 in lbs.
I have started on the top two, but have not gotten to check either as yet. Will provide results when I get them. I have a question on the ball style wrench Van's recommends. How much , if any, additional torque does this require? This was not addressed in the notice and repair procdure as the notice simply states follow the Rotax specs. which are 360 in lbs. Am I concerned over nothing on this difference?
Dick Seiders
 
Torque Wrench Calculation

Hi Dick.

I removed the drip tray. See my post a day ago. There was no way I would use a ball end allen at such an angle. My o-ring was not re-usable. Another is on order.

Since you mentioned it, I looked a bit on the internet and found the following illustration. Makes sense from simple physics but I have NOT verified the calculation. I have read many cautions with regard to using a universal joint and a torque wrench.

http://202.106.73.19/download/machine/PET-CT/GE/5177339/root/data/content/82798illd0e375.htm

Van's did not indicate any type of required adjustment due the angularity offset. Adjusting the torque wrench value if the axis of rotation is offset is WELL known. This is a bit different.

Call Van's engineering and ask. Let us know what they have to say.

Maybe Mel or one of the torque wrench gurus will comment.
 
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Mandatory

if a change was considered to be MANDATORY


Marty, Joe is right. You are now experimental and not required to follow UNLESS it is specifically mentioned in your own operating limitations that came with your own inspection by the Feds. Those are mandatory. And everyone's are not written the same.
 
if a change was considered to be MANDATORY


Marty, Joe is right. You are now experimental and not required to follow UNLESS it is specifically mentioned in your own operating limitations that came with your own inspection by the Feds. Those are mandatory. And everyone's are not written the same.

Agree.....BUT, there has to be a subset of builders where we were 15 months ago. Engine had been installed and then a month later, the notifications come from Van's to change the torque value. IS IT MANDATORY for them?
 
Yes

Until they sign the Statement of Compliance which the DAR must see to certify the AW, they would have to, yes.
 
Thanks Pete. I NOW understand. I had to read their bulletin and then digest it. I am HAPPY, I think!
 
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Thanks Marty. I will check out the math as best I can. Question on the use of ball allen wrench. I understand how you did the rt side w/o it, but were you able to do the left top w/o it as well? I am struggling with that. May weld one 8mm on top of another to try to avoid the ball on left side. How did you do it?
I will call Van's tomorrow on the torque question and provide feedback.
Dick Seiders
 
I did the same as Gary Eldrige did. Will send you an e-mail with a photo link. Not a perfect solution but it works. No need for a ball allen on the left side.

Will send my photo's and a discussion to anyone that wants them. e-mail me. Too many photos to post here.
 
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Log book entry

I should have mentioned that for those of us already flying, we are required to make an entry in the aircraft log book whenever an AD or service notice is issued. The log book entry should mention the service notice and the corrective action taken, whether that action is in accordance with manufactures instructions or an alternative corrective action determined to be appropriate by the builder. If Mel is reading, perhaps he will comment and clarify the requirements.
Joe
 
Feedback from Van's call today on torque question regarding the amount of torque added or subtracted when using the ball allen wrench angled to the head of the bolt:
Use the amount the Rotax manual calls for. (360 in lbs.). ie: the difference due to angle of wrench has negligible impact on torque applied.
Dick Seiders
 
Just what I thought

Feedback from Van's call today on torque question regarding the amount of torque added or subtracted when using the ball allen wrench angled to the head of the bolt:
Use the amount the Rotax manual calls for. (360 in lbs.). ie: the difference due to angle of wrench has negligible impact on torque applied.
Dick Seiders

There you go..... "Use the amount the Rotax manual calls for. (360 in lbs.). ie: the difference due to angle of wrench has negligible impact on torque applied." Just what I thought, but I'm sure there's some here that think they're smarter than the Van's engineers. For those I have a bridge in Florida you might be interested in.
 
There you go..... "Use the amount the Rotax manual calls for. (360 in lbs.). ie: the difference due to angle of wrench has negligible impact on torque applied." Just what I thought, but I'm sure there's some here that think they're smarter than the Van's engineers. For those I have a bridge in Florida you might be interested in.

Yes, that would be the same Van's engineers who told us that leave the powder coat, 312 foot pounds and just the split ring washer would be just fine.

They, just like us are human and from time to time make a mistake, we have all learned a lot on this one and each will take what we have learned and do what we think is correct and safe.

I just hope Van's can get past its sever NIH (Not Invented Here) issues and get back to what is safe for their customers.

Best regards,
Vern
 
I'd agree

As an engineer, I'd agree that the angle (very small) of the ball driver in the cap head screw has a negilgilbe effect on the torque-- the torque lost due to the angle is probably under the level of the accuracy of most of our torque wrenches and certainly less than the breakout or drag torque of the bolts. You could check the torque OK with the ball driver but there's no way you can get that bolt out to add Loctite without removing the drip tray. My O-ring came out of the manifold side but went back in OK.

Marty, who is "LEAF"-- Lockwood??

Thoughts on cleaning old Loctite frombolts? Wire brush in a dremel/ Acid bat" Somethnig in between??

Wayne 120241/n143WM
Now Loctited and 360 in-lbs.
 
Thanks Larry and Marty

I think everybody including Van's should thank Larry, Marty and all the others for stepping up and posting the original notices that warned of the bolts comming loose. Im afraid that Van's might not have caught it in time. There were several out there that actually lost a bolt or two. I don't think it is productive to ridicule some one for researching potential solutions to the problem. We are after all building experimental aircraft with no track record. I think we would should encourage each other to step forward with ideas and thoughts and not rely solely on Vans to take care of us. That is the purpose of the forum after all. Critical thinking is something that appears to be rare these days. Personally I have gleaned a lot of knowledge and have been impressed with amount of research that has taken place. I don't mean to step on toes but sure want to encourage my fellow builders to keep their findings and observations comming in. I truly believe that a tragedy may have been avoided.

Gary Eldridge
 
As an engineer, I'd agree that the angle (very small) of the ball driver in the cap head screw has a negilgilbe effect on the torque-- the torque lost due to the angle is probably under the level of the accuracy of most of our torque wrenches and certainly less than the breakout or drag torque of the bolts. You could check the torque OK with the ball driver but there's no way you can get that bolt out to add Loctite without removing the drip tray. My O-ring came out of the manifold side but went back in OK.

Marty, who is "LEAF"-- Lockwood??

Thoughts on cleaning old Loctite frombolts? Wire brush in a dremel/ Acid bat" Somethnig in between??

Wayne 120241/n143WM
Now Loctited and 360 in-lbs.

Using the equation I presented a few posts ago, with a 20 deg angle (I went back out and measured it), with 360 in-lbs dialed in the torque wrench, 338 in-lbs is delivered to the head of the capscrew. Insignificant. I do not know. But I do know Van 's is telling us that an increase from 310 in-lbs to 360 in-lbs should or may resolve this issue. Is 338 in-lbs OK with a ball end wrench with the 20 deg angularity? Time will tell. Measurement inaccuracy exists either way. The force to loosen is highly dependent on this preload.

I did not use the ball end. Was much more confident removing the drip pan and getting a straight shot at the capscrew. My replacement o-ring should be here tomorrow. And, you are correct. To remove the capscrew, the drip pan has to be removed anyway.

The Loctite data sheets indicate cleanup with MEK and a wire brush.

http://www.loctiteproducts.com/tds/T_LKR_BLUE_tds.pdf
http://tds.loctite.com/tds5/docs/243%20NEW-EN.PDF

LEAF is Leading Edge Airfoils out of Lyons, WI, one of the major ROTAX USA repair facilities. Ordered the o-ring from them!!

Suggest getting a current catalog from all 3 of the major repair centers. Just ordered and received one from CPS, California Power Systems. A lot of good ROTAX info. The other is Lockwood in Florida.

Thanks for the GOOD feedback from all of you guys. And no matter what, please continue to list any findings here with respect to the RV-12 as all of us continue to learn. Do not allow anyone to suppress your thoughts. If right, GREAT. IF wrong, so be it. BUT, we all learn! (I have to remind myself of the same every so often).
 
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Final Posting Rant By OP.

Well said Gary and Marty.

While we may have been lulled into a false sense of security with the "build it to the plans" mantra, it is clear as experimental aircraft builders we are on our own at times. The "plans" only go so far, this forum goes all the way. This thread / this forum stands as testament to that ideal. Thanks to all who make that possible, DR & the mods you know who you are! ;)

Vans has detailed what needs to be done to modify the cooling shroud and re-torque the 4 engine mount ring bolts. My assumption (along with Pete) is that ends their responsibility. While I hoped it would be more, in retrospect it is enough. They know what they are doing and this is their sandbox. Lets "trust" their judgment, "but verify" from time to time. ;)

My only regret is that I did not sound the alarm 6 months ago when I found the bolts loose. I thought I screwed up and did not tighten them properly to begin with. If someone would have gotten hurt or worse because I did not recognize the problem (see original post, THANK YOU TONY T!) and let everyone know sooner, ....lets just say I'm glad no one got hurt. Lesson learned.

This is why I love experimental aircraft. To build, to fly, to be a member of VAF & EAA. It is the constant learning, understanding the process, materials, engineering, and people involved in experimental aviation, and being humbled by the knowledge of others. :eek: A finer bunch of men and women there is not.

Thank you one and all who have contributed to this thread and posted the results of my initial inspection request. The inspection results you posted helped sound the alarm and get the word out as fast as possible, and I owe you a cold one. I tip my hat to all of you who lost bolts and were brave enough to post it here (at the risk of ridicule) to help sound the alarm louder and clearer. Thank you!
 
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I would like to echo the thanks, from all of us who have not even started to build, and will have things like this very important problem discovered and solved long before we even see our engine for the first time, by those with the courage to go first. I feel like I have 75 personal test pilots out there working for me.
 
Thanks to EVERYBODY

I think the value of this forum has been more than amply demonstrated once again. Larry, I think any of us would have made the assumption you did, that the problem was a personal error, not a design issue. In retrospect, it's hard to believe that such critical bolts are not saftied in any way (hindsight is great, but we do have 70 years of aeronautical "good practice" to draw upon), but none of us recognized that as an issue.

I'd really like to know if the red prototype (and Mitch's New Blue) have powdercoated engine mounts??

You guys in warmer climates keep checking those bolts! It's going to take a while to get another 5 hours on 143WM.

Thanks again

Wayne 120241/143WM
 
Firewall Bolts

Great work on this issue. Currently waiting on finish kit, just wandering how the actual engine mount mounts to the firewall? If it is bolted to the firewall has anyone checked these bolts for looseness? Just a thought.
 
Thanks for the info, engine installation looks pretty complicated. I'll study section 46 this winter. Temps 19 degrees in southern Ohio tonite.
 
I know this thread has spoken for most of the issues concerning it. I did however promise to report my findings on the bolt check. I reported earlier that the bottom two had maintained the 312 inlbs. I am pleased to report today that the top left was still at the original torque. The top right bolt moved between 1/16 and 1/8" only on the torque check to 312. I have 43.6 hrs on the flight log. I will follow with the 360in lbs with 242 Loctite, and mark with torque seal tomorrow. I plan to visually check bolts at each oil change which in my case is 35hrs. (personal choice as 3-4mos are usually required to fly off 35).
I would also like to comment that in my opinion this thread was worth it's weight in gold for all of us flying/building the 12. Thanks to all who contributed. We have a very valuable problem solving tool in these forums.
Dick Seiders
 
225 hour bolt check - -

I am changing oil and other things today, at 225 hour. The 4 bolts all seem to be exactly where I left them, so I didn't touch them. BLUE LOCTITE. Over 100 hours now, and NO PROBLEM ! ! ! As I have said all along - I highly recommend 'BLUE' on these bolts. Torque seal mark them, and you should be good to go without worry.

John Bender
 
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Bolt check

I had to remove the cowls today for a different purpose and because they were off I checked the engine mount to engine case bolts. Earlier in this thread I indicated that I was going to try the Nord-Lock washers and I did install them (no loctite). I have put 16 hours on the plane since then, not a lot since it has been a dreary snowy/rainy winter here. Anyway, I put the torque wrench on the bottom two bolts and the wrench clicked at 30 foot-pounds with NO movement of the bolts. That felt good.

A visual check of the top two was made since I did not feel removing the carbs was warranted at this point. They passed a visual check.

The Nord-lock washers are still unproven in the field for this particular application, but first indications are that they do work.

Tony
 
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I just did the modification of the cooling shroud today. I did not use the method that Vans suggests. Tony T has a picture on his photo page that I followed as a guide. Instead of grinding just the inboard corner and then glassing in a patch, he cut a segment of the shroud out. You don't need to buy a ball end allen, you can use a standard allen on a 3/8 drive. It only took 15 minutes to cut the piece out with a hacksaw blade. I used a #6 nutplate and screw to hold it in place. See his photo log for details. I think it is a much better way to go.
 
Torque

As a side note, when this first started I took all four of mine out and re-torqued them to 30 (instead of 25) as Van's suggested. 30 ft/lbs is also the number for that bolt in that single situation in the Rotax Maint Manual. In 50 plus hours of flying since I have checked frequently with no change...all four. I do still own four Nordlocks that I will install should they loosen.

Pete
 
Problem Solved

Not at this stage yet but by the lack of posts on this issue I assume no further problems reported on flying 12's ?
 
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