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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-1541531@logan.com>
Subject: Re: [FlyRotary] Normal Engine Paramaters
Date: Tue, 7 Nov 2006 11:00:44 -0500
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Hi Dennis,

Yes, here's some snippets of the data I recorded on the trip

Static at take off was 6200 rpm (a bit higher due to the colder (32F) dense 
air - my nominal static is 6000).  It is clear the prop (Performance 
74dx88p) is stalled on take off roll as you can hear the "wop,wop" as it 
stalls/unstalls as the cowl/prop interaction occurs.  After lift off the 
prop unstalls and loads-up pulling the rpm down to 5900-6000.  During more 
nominal temperatures (50F on up) I do not notice the stalled effect.

Fully loaded max rate of climb I saw on trip after take off was 1600 fpm. 
Most were closer to 1400 fpm at gross weight. My take off weight fully 
loaded is 1750 lbs.

Here are a few of the data points I logged on the trip

5800 rpm and 8 GPH fuel burn gave a TAS of 164 MPH at 6500 MSL, Oil 175F 
Coolant 170F OAT 43F

6000 rpm and 9 GPH fuel burn gave a TAS of 175 MPH at 9600 MSL, Oil 160F 
Coolant 160F OAT 39F

6400 rpm and 10.3 GPH fuel burn gave a TAS of 191 MPH at 7500 MSL, Oil 175 
Coolant 175 OAT 30F

Keep in mind that my heavy RV-6A is a bit on the draggy side with a overly 
large bottom cowl opening and two mufflers in the slip stream.  I have an 
"older" 13B (91 turbo block) so do not produce quite the HPof the newer 
Rensis engine.

I wouldn't be too concerned about your static at this point, Dennis.  Yes, 
it could stand to be a bit higher, but while I did have a 76dx88p prop 
initially,I later had 2" removed from the diameter to bring my static up 
from 5800 to 6000 rpm.  Also I found with the 76 dia prop, the "P" factor, 
Prop Stream or whatever, I did not have enough rudder control on initial 
roll at WOT.  Made for some exciting early take offs, also cutting the prop 
provided a bit more ground clearance.

It seems few folks get the static power they are looking for without some 
tinkering with the induction/exhaust.  You may find that you are a bit over 
propped, but I certainly would not do anything to the prop at this point. 
My personal opinion.


Ed

Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.dmack.net/mazda/index.html


----- Original Message ----- 
From: "Dennis Haverlah" <clouduster@austin.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, November 07, 2006 9:59 AM
Subject: [FlyRotary] Normal Engine Paramaters


> Ed:
>
> Glad to hear you had an uneventful 1500 mile trip!!  Would you post your 
> nominal static rpm, cruse rpm and gph fuel burn.   Also any cruise air 
> speed numbers and altitudes would help.  Are you still using an 88pX76dia 
> prop?  What max. climb rates are you getting?
>
> I am about to start the auto-tune exercise on my ECM..  I've got the Catto 
> 88X76 composite 2 blade prop using Tracy's 2.81 psru and so far have only 
> been able to get 5400 rpm static.  I hope to paint and assemble the A/C in 
> the next 2 months.
>
> Dennis H.
> RV 7A, James Shark cowl
> Tracy's ECM, EM, 2.8 psru
>
> --
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