Rotary aviation apex seals
 

I want to get a set of apex seals and the RA seals look quite tempting. I am a little concerned about them being too hard and wearing out the rotor housing surface prematurely. Any of you guys using these looked into that issue?

Hmm....I guess I must be only one who thinks about stuff like this before buying apex seals.

They take longer to break in and are some what harder but not to the point to where it will cause damage to housings if broken in properly. just keep it under 5k for the first 2000 yada yada yada( not 100% sure on break in time) and they should be fine

David

actually, it sort mentions that on one of their pages, it goes like this:

"The apex seal is part of a sealing system, which includes the rotor housing. In theory, the rotor housing is the more durable of the two matched parts. Since all parts that have dynamic contact will wear, it is desirable, in most cases, to design one piece to be the sacrificial lamb, and wear away, while minimizing deterioration of the other component. The apex seal is the sacrificial part in this scenario. To minimize the rate of wear on the apex seal, the rotor housing must be in near perfect condition."

Did you do a search?

The consensus seems to say increased clearances are needed to run these seals.



-Ted

Ted, I only read clearances were good for atkins seals as recommended by Judge Ito. I myself have clearanced hurley seals. No one to my knowledge has altered the dimensions of RA seals. What consensus??

I don't have any answers, but I am interested in this, too, since RA seals are going into my rebuild soon.

-Max

in my opinion, it would be safe to assume that anything used in aviation has to be good, the last thing u want is to have an engine fail in mid air.

I'm interested in clearences too, ive heard atkins need more, but nothing on these yet. also i wouldnt worry about them being to hard on the housings, they are softer then stock seals.

i've got a RWS apex seal clearancing thread started in the 2nd gen forum, although i'm waiting on some good info.

RWS says they are not recommending them for aviation as yet until they are in use for a longer time.

O, so they are softer than stock seals for sure? They did not specifically mention that on their webpage.

I thought they were harder than stock seals.

I have a set of them in packaging waiting to be put in, just need to get the rest of the stuff, ill fill everyone in on breakin etc, from a packaged standpoint they look awesome, very high quality

From RWS Website:
"These heat treated, alloy seals offer 700% more bending strength and are 85% harder than the current after market competitors (Atkins and Hurley). Introduced in August, 2003, they are being used in race and street cars around the world. Try a set and see for yourself why our seals beat the competition!"

now, i'm not sure how they compare to stock seals.

By 700% more bending strength, do they mean they are 700% more RESISTANT to bending?

Note: As compared to Atkins and Hurley.

stock apex seals are electron beam chill hardend, which basically means they melt the top few mm then cool it very quickly making them very hard,.. kinda similar to a Hamon on a katana,..) the rws seals are more then likly through hardend, and if they were made as hard as that few mm of the stockers theyd be to brittle and shatter (hardness does not equal strength), so im guessing the're through hardnend to something lower then stock levels of hardness(i hope atleast). hopefully they are hardending to a bainite structure, this would provide excelent toughness and ok hardness.

I think "bending strength" = "modulus strength"?

Yeah, increasing strength (tensile and compression) increases brittleness.  It's (metal) materials basics.

I would question if there is any significant apex seal groove enlargement due to these seals, but I guess the jruy is still out on that one until enough mileage is logged with these seals.


-Ted

now that i think about it the ultimate steel apex seals would be much like on of Howard Cark's L6 katanas, banite body with a martensite wearing edge,..bainite is super super tough and resistant to stress fractures etc,.. and martesite is very hard, which is good for a the wearing parts of the seal,..

From what I understand, if these seals fail they bend/warp and don't shatter which could save you housings and turbos.

Max just posted up a write up of his experiences so far. We found some not so encouraging things. His explanation reveals more so........

https://www.rx7club.com/showthread.p...hreadid=285884