Mailing List flyrotary@lancaironline.net Message #48711
From: Al Gietzen <ALVentures@cox.net>
Subject: RE: [FlyRotary] Re: where's the missing power?
Date: Thu, 15 Oct 2009 22:28:13 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

Mike;

Sorry to hear about your nephew.  I certainly hope that he comes out of this in fine shape.

 

It does seems that your throttle body is causing some flow restriction at WOT.  You may want to consider replacing that setup at some point with something cleaner; like a single large throttle plate.  BTW; I assume that the vacuum gauge is reading inches hg; not H20.

 

We may have been over this before; but if you can get 2300+ static prop rpm, it’s not significantly over-propped. And I don’t get the shallow dive thing – yeah, in a dive you will get higher rpm; and when you return to level (at the same altitude) you’ll be exactly where you were before.

 

Meanwhile, have some fun with that airplane; head out over the dessert.

 

Best,  Al G

 

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Thursday, October 15, 2009 7:22 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: where's the missing power?

 

Sorry for my absence on a topic I started. My nephew had a skateboarding accident last weekend and is in the hospital in a chemically induced coma until his brain swelling is under control. And I thought car powered airplanes were dangerous. Stay away from skateboards.

 

Tracy - My mixture monitor shows stoich at full throttle. I suspect an airflow issue rather than fuel.

 

Al - my vacuum gauge is located in the plenum directly behind the throttle plates.

 

Lynn - I agree that the TB inlet is horrible and needs a bell mouth. The inlet is also pretty obstructed by the cowl which isnt visible in the pics I sent. I think I'll make an attempt to clean this up some and see if it gets me anywhere. If not I'll live with it for a while.

 

Kelly - always tough to determine if the problem is an engine issue or if the load is simply too much for the engine to overcome. I'm going to experiment with the shallow dive several have suggested and see what happens.

 

Mike

----- Original Message -----

Sent: Tuesday, October 13, 2009 4:21 PM

Subject: [FlyRotary] Re: where's the missing power?

 

Since you have the vacuum gauge, this article will help you use it for troubleshooting.

 

 http://autospeed.com/cms/A_2393/article.html

 

Bill B

 


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietzen
Sent: Tuesday, October 13, 2009 7:22 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: where's the missing power?

I dont have a regular manifold pressure gauge, just an industrial type vacuum gauge ( I really gotta get an MP gauge). Anyway, the vacuum gauge was indicating 4" of vacuum.

 

Where are you measuring the 4” vacuum?  If it is near the ports it is no unusual; if it is out before the runners; something is wrong.

 

Al

Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster