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-   -   RV-12: Engine Mounting Cap Screws Inspection (https://vansairforce.net/community/showthread.php?t=65020)

Mich48041 12-05-2010 12:36 PM

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

dick seiders 12-05-2010 01:54 PM

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

MartySantic 12-05-2010 02:38 PM

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/machin...8illd0e375.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.

Peterk 12-05-2010 03:42 PM

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.

MartySantic 12-05-2010 03:59 PM

Quote:

Originally Posted by Peterk (Post 491022)
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?

Peterk 12-05-2010 04:36 PM

Yes
 
Until they sign the Statement of Compliance which the DAR must see to certify the AW, they would have to, yes.

MartySantic 12-05-2010 05:45 PM

Thanks Pete. I NOW understand. I had to read their bulletin and then digest it. I am HAPPY, I think!

dick seiders 12-05-2010 06:21 PM

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

MartySantic 12-05-2010 06:29 PM

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.

Mich48041 12-06-2010 08:13 AM

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

dick seiders 12-06-2010 12:19 PM

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

rschy 12-06-2010 03:55 PM

Just what I thought
 
Quote:

Originally Posted by dick seiders (Post 491303)
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.

vernhendershott 12-06-2010 06:02 PM

Quote:

Originally Posted by rschy (Post 491376)
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

yankee-flyer 12-06-2010 08:24 PM

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.

Mel 12-06-2010 08:28 PM

LEAF
 
"Leading Edge Air Foils" is a Rotax service center.

jersey 12-06-2010 08:29 PM

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

MartySantic 12-06-2010 08:55 PM

Quote:

Originally Posted by yankee-flyer (Post 491477)
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).

Geico266 12-06-2010 10:28 PM

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. :o 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!

DonFromTX 12-07-2010 06:51 AM

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.

yankee-flyer 12-07-2010 08:05 AM

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

lewy 12-07-2010 08:48 AM

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.

dick seiders 12-07-2010 10:39 AM

Lewy, those bolts are locked with a cotter key after torqueing.
Dick Seiders

Jetguy 12-07-2010 03:17 PM

Answer to your question!
 
Lewy. Go to this link and you will see on page 10 how the motor is bolted to the firewall.

http://www.vansaircraft.com/pdf/revi...Section_46.pdf

lewy 12-07-2010 08:23 PM

Thanks for the info, engine installation looks pretty complicated. I'll study section 46 this winter. Temps 19 degrees in southern Ohio tonite.

dick seiders 12-09-2010 03:43 PM

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

JBPILOT 03-17-2011 11:30 AM

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

Tony_T 03-17-2011 05:32 PM

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

Mark Henderson 05-19-2011 07:51 PM

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.

Peterk 05-20-2011 08:39 AM

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

Jamesey 08-03-2011 12:25 PM

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 ?

JBPILOT 08-03-2011 01:17 PM

That'd be my assumption - -
 
275.4 hour written in log book this morning. You can actually put your arms under the prop and lift the nose off the ground, and you can feel if anything is coming loose. I have checked mine each time I have the top cowl off, and everything seems to be staying in place. 'BLUE' & 30# torque, and mark them. Should be good to go.

John Bender

Peterk 08-03-2011 02:00 PM

245 hours here...no problems.

Pete

Geico266 08-03-2011 04:38 PM

200 hours and they have not budged. Blue loctite and retorqued.

Thank you one and all for all your testing, hard work, and posting to this critical subject.

JBPILOT 08-22-2011 10:35 AM

Positive report - -
 
I have not had the cowls off for a while, so I took both off this morning just to look at everything.

290.5 hours after a test flight, and the engine mounting bolts have not moved. They have over 200 hours with Locktite 'blue', and 30# torque. Didn't see anything else of concern, so I checked the carb balance again. Adjusted it a tich. Good to go.

John Bender

Geico266 04-11-2012 12:30 PM

Quote:

Originally Posted by funflying (Post 648822)
John,

This information has showed up on many different threads but I noted your hours report and wanted to get your input on senders.
Glad to read the cap bolts are holding well with torque and blue loctite.

My question is are still using the same :
-fuel sender
-oil pressure sender
-fuel pump
?????

Thanks

It would be better to start a new thread on your subject. This helps stop thread drift into another subject, when the engine bolts are pretty serious.

johns4689 05-02-2012 07:24 AM

RV-12 engine mounting bolts
 
75 hours on my RV-12 and I'm the next victim. All bolts were loose and the lower right was ready to fall out. My problem is getting to the top left bolt. I guess I'm in ounting boltsfor some tedious work.

MartySantic 05-02-2012 07:40 AM

John,

Were the bolts torqued to the NEW value (360 in-lbs)? Did you use blue locktite? To access the upper left, you will have to modify the shroud. I cut a piece out of the shroud as suggested by another builder. The piece is thus, removable. The service bulletin has you modifying that portion of the shroud and doing a bit of fiberglass work.

Tony_T 05-02-2012 10:01 AM

Quote:

Originally Posted by johns4689 (Post 655397)
75 hours on my RV-12 and I'm the next victim. All bolts were loose and the lower right was ready to fall out. My problem is getting to the top left bolt. I guess I'm in ounting boltsfor some tedious work.

John, you didn't say whether your engine has the original cooling shroud or the later modified one. If you have the later modified one you should be able to get a ball-end allen on the top left bolt after removing the carb. If you have to take off the drip pan you will need to replace the O-ring so you might consider ordering that ahead of time. You can find the part number in the online Rotax Illustrated Parts list.
If you have the original cooling shroud then you will need to modify it. As Marty said the service bulletin shows how to modify it. Before the company service bulletin came out some of us did it by making a removeable piece to allow access to the bolt:

More pics here on this mod.

Tony

johns4689 05-02-2012 03:47 PM

Thanks for the pictures. I have the original shroud. I'll start working on cutting a piece out tomorrow. I know the bolt is loose because the allen head is up against the shroud. I had the bolts torques to 26 lbs but did not use locktite. I now have them torqued to 30 lbs. and am using blue locktite.
It was scarey seeing the lower right bolt ready to fall out.

jersey 05-02-2012 07:08 PM

Kind of scary ain't it....:eek:

Looks like you found the pictures your looking for.

Gary


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