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Building Tips and technical articles. => 1/2 A building. => Topic started by: Phillip Kenney on September 05, 2012, 10:57:34 AM

Title: Norvel engine pressure
Post by: Phillip Kenney on September 05, 2012, 10:57:34 AM
On a Norvel .061 whci is better, the pressure tap on the muffler or the cover plate with a pressure tap> I have an older engine which has neither so if Im going to buy either a muffler or backplate I might as well get the most efficent one.
Title: Re: Norvel engine pressure
Post by: ray copeland on September 05, 2012, 11:01:41 AM
Phillip, the muffler pressure is pretty much plug and play, the pressure tap takes some getting used to, i gave up on it.
Title: Re: Norvel engine pressure
Post by: Larry Renger on September 05, 2012, 11:04:34 AM
Unless you drill the venturi out farther, muffler pressure is quite satisfactory for stunt flying.  With the much higher pressure from a backplate tap, the needle gets touchy. 
Title: Re: Norvel engine pressure
Post by: Bill Little on September 05, 2012, 12:02:07 PM
I agree with Ray and Larry.  Unless you are going for a speed class or combat, go with the muffler pressure.

BIG Bear
RNMM/AMM
Title: Re: Norvel engine pressure
Post by: Heman Lee on September 06, 2012, 08:36:58 PM
Unless you drill the venturi out farther, muffler pressure is quite satisfactory for stunt flying.  With the much higher pressure from a backplate tap, the needle gets touchy. 

What about the AME (3 port) version.  Has anyone use backplate or muffler pressure to get a consistent run without using a bladder?
Title: Re: Norvel engine pressure
Post by: L0U CRANE on September 07, 2012, 01:24:22 PM
Heman,

Never flew one that way. Those are the bathtub intake silver fin version?

On the bench, they were still tricky to start and set, repeatable restarts didn't happen for me on  backplate tap pressure. Limited experience but still one comment...
Title: Re: Norvel engine pressure
Post by: Trostle on September 07, 2012, 05:39:50 PM
Heman,

Never flew one that way. Those are the bathtub intake silver fin version?

On the bench, they were still tricky to start and set, repeatable restarts didn't happen for me on  backplate tap pressure. Limited experience but still one comment...

The AME and the Big Mig engines came with either the small silver fin version or the larger dark fins.

An electric starter is almost a must, with or without pressure.  Yes, they can be started by hand, but why go through the aggravation?

Muffler pressure still works with the AME (high performance) version, but for all out speed/power, back plate pressure is best.  Makes needle settings a bit more tricky.