Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

smoother engine bearings

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Old 12-06-2002, 04:22 AM
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FlooredCOBRA
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Default smoother engine bearings

The other day while at our field I was talking to a few guys about bearings in the engines. Somehow we got on the subject. One mentioned that they have this company that makes ceramic bearings a supposedly they do not wear like the metal ones we use and turn much smoother.

Does anyone out there have any info on this or heard of this? I am curious.
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Old 12-06-2002, 06:06 AM
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I have no experience with ceramics, but I would think if there was a benefit to them the Nelsons, Jetts, etc. of the world use them.

BTW, a worthwhile upgrade for most engines are the bearings that are sold by Performance Specialties. Same Swiss made units as Nelson uses. They have proven to be more durable than the originals in my Rossi .53. And as to smoothness, these are the best I have felt.
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Old 12-06-2002, 07:03 AM
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This is true.

But i only hear about this from some guys at the club.
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Old 12-06-2002, 01:05 PM
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Default smoother engine bearings

I specifically asked Dub Jett about ceramic bearings when I ordered my Bar Stock Jett 50 FIRE -
He said:" They are a waste of money."
Based on everything that I've emailed Dub Jett about, and a few phone conversations, I believe him.
If you read what he has to say on his website, you'll see that he does change his opinion - after firsthand experience and evidence shows that the change is good.
Example: Read the FAQ about AAC liners vs. ABC - Dub says that years ago, he would have agreed that ABC were better - now, he thinks that AAC are better, and goes on to explain why he changed his mind.
For now, he sees no benefit in ceramic bearings - if a person wants to pay more for the same performance, that is up to them.
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Old 12-06-2002, 06:15 PM
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George
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I specifically asked Dub Jett about ceramic bearings when I ordered my Bar Stock Jett 50 FIRE -

Maybe it's because at the RPM's these engines turn aren't gaining any benefits. On the other hand though, ceramics are used in turbines, but then again we're talking 120,000 + RPM's. I think maybe this is where the difference may come in.

Not an expert by any means, just my .02

George
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Old 12-07-2002, 02:01 AM
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Default smoother engine bearings

Here is where I have read they come from:

http://www.bocabearings.com/

The reason why ceramics are necesary is because of high temperatures. Probably a waste of money on R/C IC engine as the internal temps never get that high inside the crank case.

A jet might see 1000+ degrees internally, but a R/C IC head temp usually doesn't get much hotter than 450 degrees (remember aluminum melts at a relatively low temp). I would wager R/C IC engine bearing do not even get that hot (especially the front bearing).

I once saw an article several years back discussing the advantages/disadvantages of plainbearing engines for high performance applications - stating that if the engine didn't last long anyway because of extreme use = high RPMs (this was about ducted fan / racing boat engines), then why waste the $ on the more expensive castings and bearings?
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Old 12-07-2002, 02:19 AM
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Default smoother engine bearings

I was just wondering about the bearings. I am not going to go out and buy any. What I have in there works just fine for me. I was just curious on what others thought about this or heard.
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Old 12-08-2002, 01:56 PM
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Default smoother engine bearings

Ceramic bearings are available from Boca Bearing.

The Nelson and Jett engines probably dont use them die to the fact that two bearings are worth more than half the price of a new Jett! Not many guys will part with the $250 or so for a Jett 46 or 50 allready, if it cost an additional $120 they wouldnt sell many. (by the way I own and run Jett's and think they are the best engine for rc use)

There are many benifits to ceramic bearings, longer life, smoother operation and yes they can take the heat. But, in an internal combustion engine, the bearings wont even see a fraction of that heat, and are not necessary. The higher quality prescision bearings with the phenolic cages (which are allready 3X the cost of a normal bearing replacement) are super, and you wont lose a cage at high rps either.

Just my experience and $.02...

Andrew Coholic
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Old 12-15-2002, 09:36 PM
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Default smoother engine bearings

Hi!
I think Nelson uses Swiss, WIB bearings in C3 quality ( C3 is a norm for a bearing with more play than a standard bearing )
MVVS also has these bearings in their Q-500,.45 and .49 engines.
The .40 could be equiped with these too but they are not installed at the factory.
C3 or C4 bearings are often used in pylonracing engines.

Regards!
Jan K
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Old 12-29-2002, 09:19 PM
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Default ceramic bearings

In the new F3D engines like the world champion MB 40 we use ceramic bearings with big success. In our experience the last longer and they dont chance the play in the bearing while the engine became hot. We use normaly WIB from Swizerland in C4 now we use ceramic balls in the bearings.
It is also very helpfull to use only one ball in ceramic because this singel ball maks the bearing very clean and polished the bearing inside.
In Germany the ceramic bearings are not such expensive than in USA. Mostly we buy only the balls and chanched them ourself.
Ceramic bearings last 10 times longer than steel onces under very hard conditions.

Best regards M. Jakob
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