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Slat bumper strips

Started by yukonranger, April 26, 2021, 09:39:03 PM

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My slat bumper strips are starting to show some deterioration.  Does anyone know what the specifications were for the material used?  Mine look as much like weather stripping as anything else.  Thanks


I tried many different kind.  Up to now, the close cell foam gives better results in terms of keeping the same thickness from the beginning of a flight to the end.  Open-cell foam, and the ones that approach "memory foam" , just compress too much after 15 minutes. 

One thing NOT to try is the non-continuous bumper dot.  One day, C-FZWL H-250  was fitted with them instead of a continuous strip just for a ferry flight when they were waiting for the continous strip.  The slat started to vibrate so hard that all the rivets became loose.


Doug Johnson

Those foam weatherstrip bumpers are an interesting subject. You may have noticed that a large portion of the flying Helios don't have them and don't really seem to miss them, maybe because they aren't a Helio part or because there is a rubber bumper on the tomahawk that they feel is sufficient. I will add a pic of the parts list that shows that rubber bumper part number.

Larry Montgomery recommended the foam weatherstrip because they softened the slat retraction bang and he thought they probably acted as a gap seal when the slat was retracted in cruise.

At one time I had the 3M part number for the best weather strip but it was written some place in the my illustrated parts book (I think I also had a page for other vendor parts) that book probably wound up with Kevin Dunn.

I tried using some soft white colored weather stripping once but in spots where it wasn't compressed tightly it would erode from the high speed air. If I remember correctly what I used was a grey foam with a sticky back from 3M.

And speaking of C-FZWL it doesn't show a canceled registry for export in the Canadian registry but does show up as a cancelled registry back in '13 in the American registry,

Any one know what is going on there?

history paragraph



So finally, the Helio were going out of the factory without weatherstrip ?


Doug Johnson 1

Louis, I really don't know. I just know that when I was putting my Helio together in '94 it didn't have the weatherstripping and didn't get it put on for about a year.  Larry Mongomery gave me several rolls of 3-M weatherstripping about 20 feet long along with some other parts when I was leaving Spartenberg the weatherstrip was put on after the ferry trip to AK. Then later when I removed the paint I didn't have enough weatherstripping to replace what I removed and I couldn't find a part number or any mention of the weather stripping in the repair manuals. I tried several different weatherstrips that came from the hardware store before finding a 3-M version that worked. I don't remember paying much attention to whether other different Helios had the weatherstripping or not.

I just don't think the watherstripping was a Factory application from my own experience.

If I'm wrong please correct me.


The slat seal is called out on the Helio drawing for slats. It gives a Globe part number which of course is no longer available. I've used a closed cell foam 3/8"X3/16" for a lot of years. CGR Products in Greensboro NC carry it by the roll and it isn't very expensive as I recall. I can't read the PN on the roll I have anymore. It comes with a sticky-back which holds well to a clean slat. I think the primary purpose of the seal is to limit airflow under the slat for a more efficient wing. Additionally it keeps the slat from banging against the wing when it nests and lowers any vibration. Jim

Kevin Dunn

I have some of the CGR foam that Jim mentioned if needed. Let me know.



I sometimes confuse bumpers with seals. Seals are on backside of slats and bumpers inside wing as stops for the torque tubes.  When JAARS was doing our annuals they always stressed the importance of the seals and always replaced missing or loose pieces.  We noticed that missing seals could cause a bit of flutter in the slat that was sometimes visible in the camera. We also noticed rubbing on the wing from slats without seals. BTW if anyone has a couple of bumpers please let me know or know the material and dimensions so we can make a couple. Thanks

Jason Stephens

I think I still have some left over new bumpers.  I'll check and let you know.


Great. Thanks. I believe JAARS told me a few years ago that they had some made by a company in Baltimore. 

Hart Drobish

Greetings, It has been a while since we last looked for the wing slat rubber bumper stops donuts. Does anyone have a source, or at least a material specification that could be used to fabricate them ?    We would appreciate a lead on sources. Thanks, Hart


Quote from: Kevin Dunn on May 13, 2021, 05:03:04 PM
I have some of the CGR foam that Jim mentioned if needed. Let me know.



Where can I get that material as my strips are beginning to deteriorate?



Jim metzler source is where I previously purchased mine. Put that on hmmmm at least 5-6 years ago. Lasted quite awhile and was better than original foam on it when I purchased the plane

Kevin Dunn


I have some in stock. I'll text you.