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Lower baffle tie...

Michael Burbidge

Well Known Member
I followed Vans directions in making this lower baffle tie. Does it look acceptable?

Also do you know if the steel rods that are used in the hinges for the cowl are the same stuff that is used for the baffle ties. I messed up my first attempt and I have some of the rod left over from the cowl. I measured it with my calipers and it is exactly the same thickness.

Thanks,
Michael-

mj1inRz.jpg
 
Not sure how correct mine are......
DAF3EE6F-C000-4B24-8B91-9723A8D492D9-7471-00000420765E413A_zps2c9cdf7d.jpg

I bent mine so the didn't touch anything but there is nothing to keep them from twisting and then contacting the head or lower baffles. I had some extra tubing (brake line I think) that was the same stuff Vans sent in the baffle kit that I covered my lower baffle ties with. Parker para flex 1/4 od x .62 wall, it was a tight fit (I had to twist it on) over the tension Rod threads and after hand threading the second one on I got the bright idea to chuck the tubing into my cordless drill and it worked great!
I also ground a flat spot on the washer so it sits flat on the baffle.
 
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Hey guys, FWIW...

I am at that point RIGHT NOW and my local inspirational airplane is exactly the same as the one I am building has had a problem with these rods tearing through the baffle material. Either the material is too thin, the force on the 6/32 washer is too high or he simply tightened it too much. Maybe all could be true or it could be something totally different!

Any way you slice it, I am going old school here. The RV-6 I fly has tie wire connecting the lower baffles. It was the way Van used to suggest the baffles got tied, it worked well on the -6 and the inspirational -7 I am copying changed to it and it is working well for him now.

I made little barbells on the lathe so that the force will be spread out across a greater range across the flange of the baffle.

I will post up some pictures to show you what I mean later.

Others, have you had any problems with tearing these flanges off using the 6/32 nut and washer method or is this an isolated experience?

IMG_0080.JPG


IMG_0122.JPG


THE CULPRIT:

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:confused: CJ
 
On the advice of another builder, I tapped the threads far enough to allow the installation of another pair of nuts on the opposite side of the baffle flange.

It allows one to tighten the connections, so that the rods don't rotate, without putting a lot of tension on the system.
 
good info

Perfect timing on this thread....installing new baffeling on existing plane now....good information here....thanks for posting guys!
 
.... my local inspirational airplane is exactly the same as the one I am building has had a problem with these rods tearing through the baffle material. Either the material is too thin, the force on the 6/32 washer is too high or he simply tightened it too much

It's impossible for the nut and washer to apply even pressure to the sheet metal flange; the edge of the fastener digs in at the bend.....a miniature can opener.

Can%20Opener.jpg


Ye olde safety wire method:

Baffle%20Tie.jpg


There is a washer in the wire loop at each end. Wire and washer get a blob of oil resistant silicone to kill fretting. Two drilled holes, not one; the wire does not loop around an edge. Note the cylinder head wire does not attempt to span two cylinders, i.e. does not run from the front wrap on cylinder 2 to the rear wrap on cylinder 4. Bend the flange on the inter-cylinder baffle so you can tie up individual cylinders. Think about it....the cylinders vibrate individually. You wouldn't attempt to use a one-piece baffle sidewall at the valve covers.
 
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It's impossible for the nut and washer to apply even pressure to the sheet metal flange; the edge of the fastener digs in at the bend.....a miniature can opener.

uyiib.jpg

Yah, RIGHT! What HE said!!!

That is why the little barbells are just the ticket!

Gimme a day and I will post up my pics...

;) CJ
 
.041" safety wire has worked fine for almost 1400 hours on mine. Threaded rod seems like a solution without a problem, not to mention the problem pointed out by Dan.
 
I riveted #8 nutplates to the flange then used safety wire to secure. I thought about using #10 nutplates with drilled shank bolts through them but decided it was overkill.
 
wish I had this post last month

Home last month for my 2 week deployment R&R, planned to finish the lower baffle attach, but was baffled. Thought about safety wire but afraid to deviate, should have asked back then. By the way my tapered ECI fins added another unexpected twist. I will reattack when I get home.

This is great info and thanks for the pictures.
 
I am a couple of months away from the baffles so this is a great thread. I like the looks of Dan's safety wire but am not sure I understand the washer. The best I can figure it is just flopped off to one side. I like the dog bone idea but making them would be a pain and the might fall off if the wire were to loosen. Then I thought about Walt's idea and mixed the two. How about using the two rivet holes in a nutplate as a washer. Ignoring the center hole. Therefore using the two holes that Dan uses but with better backing. Then maybe not as the washer probably has more surface area.
 
On my RV-6 I made one end spring loaded and put a hook on the other end so the rod could be removed in a few seconds.

My mantra is make everything easy to work on!
 
Lots of ways to skin the cat. I used the safety wire method. I riveted on an .032 doubler and then used a SS washer with a slightly flared out cotter pin across it, kind of like the dog bone idea. Over 500 hours on that set up with no sign of wear.
 
Baffle Tie

I used small but stiff springs under the nut with washers at each end of spring. There is a lot of thermal expansion/contraction going on. Still looking good at 1000 hours.
 
Flattened the washer...

Tons of good ideas here. Thanks for all the suggestions. I'm going to stick with the threaded rod for now and watch it closely for awhile. I did flatten one side of the washers like someone suggested earlier in this thread. The washer and nut now sit flat against the flange and do not dig into the inside of the corner of the flange. I feel much better about it.

Here's another picture with the flattened washer.

otLn5PG.jpg


I made two other ties tonight. One more to go!

Michael-
 
Another idea

This is what we're using on our non-RV Lycoming O-360 installation. The screw heads are cross-drilled and either safetied or cotter pinned.

Cylinder%2520Baffle%2520Assembly.JPG
 
Trim baffle flange

Dan
I noticed on this photo you enclosed that you trimmed the flange on the end of the baffle. I think I need to do that. My flange won't clear that tube also shown in your photo. Is this a common problem that the flange won't fit above that tube so part of the flange needs to be trimmed off or bent up. Is this the copilot rear flange? Looks like it. Thanks for any ideas or insights you can offer on getting this right rear baffles to fit.



It's impossible for the nut and washer to apply even pressure to the sheet metal flange; the edge of the fastener digs in at the bend.....a miniature can opener.

uyiib.jpg


Ye olde safety wire method:

9v827m.jpg


There is a washer in the wire loop at each end. Wire and washer get a blob of oil resistant silicone to kill fretting. Two drilled holes, not one; the wire does not loop around an edge. Note the cylinder head wire does not attempt to span two cylinders, i.e. does not run from the front wrap on cylinder 2 to the rear wrap on cylinder 4. Bend the flange on the inter-cylinder baffle so you can tie up individual cylinders. Think about it....the cylinders vibrate individually. You wouldn't attempt to use a one-piece baffle sidewall at the valve covers.
 
Steve, remember that Lycoming didn't design the baffle wraps. It's a airframe construction task, and it has been done many ways.

Just do what works!
 
Loose hose clamp in pic

Blain, that is probably an old pic but.... your hose clamp on the oil return hose is loose and off the hose. Might consider using constant pressure "mickey mouse ear" hose clamps if you are in there tightening things or at annual. ACE hardware has them... they don't extrude the rubber hose through the worm gear slots
 
lower baffle ties

I added doublers to the lower baffle tie flanges/holes and planned to use the safety wire method. Also riveted a center tie tab to the middle under cylinder baffle plate that comes from lycoming as a center tie point for the fore and aft cylinder baffles. It was recommended here somewhere not to tie the front and rear cyl baffles together as the cylinders move around independently.

My question is has any used strong extension springs to tie and hold the under baffles tight to the cylinders?

Thanks
 
Check them once in a thousand hours. Don't overtighten either... :)

baffle%20worn%20-%201.jpg

I laid a bead of RTV on the edge of the baffle to limit the cylinder fins from cutting into the baffle. Aerosport Power turned me on to this.

2000 hours later and no fins cutting into the baffle.
 
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