X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ww0-f50.google.com ([74.125.82.50] verified) by logan.com (CommuniGate Pro SMTP 5.4c2o) with ESMTPS id 4872243 for flyrotary@lancaironline.net; Wed, 16 Feb 2011 09:03:31 -0500 Received-SPF: pass receiver=logan.com; client-ip=74.125.82.50; envelope-from=rwstracy@gmail.com Received: by wwf26 with SMTP id 26so1331976wwf.7 for ; Wed, 16 Feb 2011 06:02:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; bh=1s3sq1JKtLudg+EgEVFYYpUABNPTTmNk1yNZWEPXanI=; b=QYsErzwEEdJ/zhecaxZigPXEgrN1v9yizu6GB9f7LO96jGanfeRc2fLWAHgZ1RuoAj uOrvDE+d8muGmdIfnavc28rI5NufxjD19VB6tsaKWUd+OPqPjqVn6On9xdIyxviQa2jg EPq/RQ5CdGJLF45Lb+BMS2BcVqN2MTt4bQya0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; b=kknmjoV8NyBc8T7jZDuwRpaWMBStNi0hbDSlXP+r7JC5GWEE0KW+suCgsglfOFZfN4 KfF6hBJIjf6Zvjsuw/Gjfg1GxwLteVZm0sdYGav2sDDHi2yOEPDFlEMvzarA+ITHWdDy Ck/Cg6aFeFNRmGVsUoU6cEJ6etpPYOKE0FG0g= MIME-Version: 1.0 Received: by 10.216.20.141 with SMTP id p13mr559918wep.102.1297864974744; Wed, 16 Feb 2011 06:02:54 -0800 (PST) Sender: rwstracy@gmail.com Received: by 10.216.59.65 with HTTP; Wed, 16 Feb 2011 06:02:54 -0800 (PST) In-Reply-To: References: Date: Wed, 16 Feb 2011 09:02:54 -0500 X-Google-Sender-Auth: 8QzT_erViiHlQNBOxfsuJafMxuY Message-ID: Subject: Re: [FlyRotary] Re: Ceramic Apex Seals....curiosity REceramin/carbon/steelst From: Tracy To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=00163646da74c93c3e049c66bc36 --00163646da74c93c3e049c66bc36 Content-Type: text/plain; charset=ISO-8859-1 What I know (and don't know) about apex seals: I have never used ceramic seals but I do talk to a lot of car racers who have. (98% of RWS customers are car guys, not aviation folks). The Pros: From their feedback it sounds like ceramics will last virtually forever, their lower weight allows higher rpm limits and they are kind to the chrome on rotor housings. The Cons: They are strong but brittle. Detonation in turbo engines will break them just like stock seals. Worn out rotor grooves will break them in NA engines. They cost a lot. If I were building an engine that had nice fresh parts AND had an extra $1800.00 to spare, I'd use ceramics but only for the feel good / cool factor. I have used stock and RA seals and never come close to wearing either of them out. Stock seals were worn about 30% of allowable limits after 956 hours of flight time. RA seals were about 25% worn after 560 hours of flight. I do not know the percentage of wear that happens during break-in period but it's probably not linear. Rotary engines have a longer break-in period than piston engines based on the compression tests I've run at annuals. Mine took 250 hours to get highest compression readings. The new 2 piece stock seals will probably last a bit longer than RA seals but if anything bad does happen to stock seals (fracture due to rotor wear, FOD, detonation, etc) they take expensive parts along for the ride. RA seals can and do fail but the failure modes are non destructive to other parts of the engine. That is the main reason why the car guys use them. They would not care if the wear life were only 50% of stock because they never expect to get anywhere close to that. Tracy On Tue, Feb 15, 2011 at 8:29 PM, Dustin Lobner wrote: > For what it's worth, I called Adam at www.rotaryengines.com and had a half > hour discussion with him about things. He was remarkably open about putting > it in an aircraft (a lot of other places won't give you the time of day if > they hear "aircraft" as I'm sure some of you know). I said that for an > aircraft he wouldn't put in ceramics because they're more there for > super-high stress situations like drag racing, but for an aircraft the > cost:benefit ratio isn't there. Plus, he's not 100% convinced on the > reliability. > > Dustin > > On Tue, Feb 15, 2011 at 6:26 PM, wrote: > >> In a message dated 2/15/2011 11:58:49 A.M. Eastern Standard Time, >> cbarber@texasattorney.net writes: >> >> Heck, tearing down my engine seems to be a routine event as of late >> >> That was my understanding too....about being nicer to the housings. >> >> I was just wondering about what I don't know or what could be expanded on. >> >> Like Dave said, minding parameters is the proper course but I would like >> to have as clear an understanding as possible for my own edification. >> >> >> Ceramics have now come of age in many areas. Any machine shop has tooling >> in the form of ceramic triangles that clamp into tool holders. It maters not >> if the work piece is heat treated, or harder than Chinese arithmetic, the >> ceramic bits go through it like it was butter. The bits are cheap, and >> discarded if fouled or dulled. >> >> Ceramic apex seals are the gold standard of apex seals. No detectible wear >> on the seals or the housing chrome. In our case for two seasons of racing. >> Stronger than steel. Oblivious to high temperatures. >> And for racing, track the housing shape at any RPM, using doubled springs, >> and even with twice the spring pressure, have less than half the drag of a >> carbon seal, and far less than stock steel seals. An automatic 5 HP over >> steel seals. Ceramics are so light that you cannot help but grin when you >> pick one up. >> >> Ceramics do survive detonation events that would put all steel seals in >> the muffler. But not for long. >> >> I have read that RA seals also hold up well. Ceramics are used in nearly >> all pro racing applications. >> >> I sold a used set to another racer for $500.00. They were identical to new >> seals after two years of service. >> >> The down side is cost. And for one piece seals, typical of racing >> applications, you must be sure you have the minimum end clearance, about >> .0015". >> >> There have been efforts to develop a two piece seal that is less sensitive >> to length variations, as they run at zero end clearance for much better cold >> starting. >> >> Mazda competition sells racing ceramics, probably Linetties. There are >> other manufacturers. >> >> Here is one. >> >> http://www.nrsrotorsports.com/ >> >> Lynn E. Hanover >> > > --00163646da74c93c3e049c66bc36 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable What I know (and don't know) about apex seals:

I have never used= ceramic seals but I do talk to a lot of car racers who have. (98%=A0 of RW= S customers are car guys, not aviation folks).

The Pros:=A0=A0 From = their feedback it sounds like ceramics will last virtually forever, their l= ower weight allows higher rpm limits and they are kind to the chrome on rot= or housings.

The Cons:=A0 They are strong but brittle.=A0 Detonation in turbo engine= s will break them just like stock seals.=A0 Worn out rotor grooves will bre= ak them in NA engines.=A0=A0 They cost a lot.

If I were building an = engine that had nice fresh parts AND had an extra $1800.00 to spare, I'= d use ceramics but only for the feel good / cool factor.=A0
I have used stock and RA seals and never come close to wearing either of th= em out.=A0 Stock seals were worn about 30% of allowable limits after 956 ho= urs of flight time.=A0 RA seals were about 25% worn after 560 hours of flig= ht.=A0 I do not know the percentage of wear that happens during break-in pe= riod but it's probably not linear. =A0 Rotary engines have a longer bre= ak-in period than piston engines based on the compression tests I've ru= n at annuals.=A0 Mine took 250 hours to get highest compression readings.= =A0 The new 2 piece stock seals will probably last a bit longer than RA sea= ls but if anything bad does happen to stock seals (fracture due to rotor we= ar, FOD, detonation, etc) they take expensive parts along for the ride.=A0= =A0 RA seals can and do fail but the failure modes are non destructive to o= ther parts of the engine.=A0 That is the main reason why the car guys use t= hem.=A0 They would not care if the wear life were only 50% of stock because= they never expect to get anywhere close to that.

Tracy

On Tue, Feb 15, 2011 at 8:29 PM= , Dustin Lobner <dmlobner@gmail.com> wrote:
For what it's worth, I called Adam at www.rotaryengines.com and had a half hour dis= cussion with him about things.=A0 He was remarkably open about putting it i= n an aircraft (a lot of other places won't give you the time of day if = they hear "aircraft" as I'm sure some of you know).=A0 I said= that for an aircraft he wouldn't put in ceramics because they're m= ore there for super-high stress situations like drag racing, but for an air= craft the cost:benefit ratio isn't there.=A0 Plus, he's not 100% co= nvinced on the reliability.

Dustin

On Tue, Feb 15, 2011 at 6:26 P= M, <Lehanover@aol.com> wrote:
In a message dated 2/15/2011 11:58:49 A.M. Eastern Standard Time,=20 cbarber@texa= sattorney.net writes:
Heck,=20 tearing down my engine seems to be a routine event as of late=20 <sigh>

That was my understanding too....about being nicer to= the=20 housings.

I was just wondering about what I don't know or what= could be=20 expanded on.

Like Dave said, minding parameters is the proper cour= se=20 but I would like to have as clear an understanding as possible for my own= =20 edification.

=A0
Ceramics have now come of age in many areas. Any machine shop ha= s tooling=20 in the form of ceramic triangles that clamp into tool holders. It maters no= t if=20 the work piece is heat treated, or harder than Chinese arithmetic, the cera= mic=20 bits go through it like it was butter. The bits are cheap, and discarded if= =20 fouled or dulled.
=A0
Ceramic apex seals are the gold standard of apex seals. No detectible = wear=20 on the seals or the housing chrome. In our case for two seasons of racing.= =20 Stronger than steel. Oblivious to high temperatures.
And for racing, track the housing shape at any RPM, using doubled spri= ngs,=20 and even with twice the spring pressure, have less than half the drag of a= =20 carbon seal, and far less than stock steel seals. An automatic 5 HP over st= eel=20 seals. Ceramics are so light that you cannot help but grin when you pick on= e up.=20
=A0
Ceramics do survive detonation events that would put all steel seals i= n the=20 muffler. But not for long.
=A0
I have read that RA seals also hold up well. Ceramics are used in near= ly=20 all pro racing applications.
=A0
I sold a used set to another racer for $500.00.=A0They were identical = to=20 new seals after two years of service.
=A0
The down side is cost. And for one piece seals, typical of racing=20 applications, you must be sure you have the minimum end clearance, about=20 .0015".
=A0
There have been efforts to develop a two piece seal that is less sensi= tive=20 to length variations, as they run at zero end clearance for much better col= d=20 starting.
=A0
Mazda competition sells racing ceramics, probably Linetties. There are= =20 other manufacturers.
=A0
Here is one.
=A0
=A0
Lynn E. Hanover


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