Mailing List flyrotary@lancaironline.net Message #51872
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Latest engine run
Date: Sun, 8 Aug 2010 20:08:23 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sounding good, Brian
 
My spreadsheet indicates that at 5660 rpm with a 12.5:1 Air/Fuel ratio (rich) with 100% Ve the engine could be producing 161 HP with a fuel burn of  15.0 gph (did you happen to notice what your fuel flow was?).
 
Your engine would be producing  4940 BTU/min (coolant discharged) and 2470 BTU/min( oil discharged) of waste heat.  Your prop rpm with the 2.85:1 gear box would have been 1951 RPM. 
 
This is all assuming standard sea level conditions 29.92 and 59F Air/fuel of 12.5:1 and a bfsc of 0.55 - any changes to those variable will affect the power production calculation.
 
If you can wind the engine to 6800 rpm then with the same (best power) air/fuel ratio and 100% Ve it should produce 197 HP turning your prop at 2386 RPM burning approx 18.3 GPH.
 
Ed

Sent: Sunday, August 08, 2010 7:28 PM
Subject: [FlyRotary] Latest engine run

A few weeks ago I wrote that I had run up the engine to 4500 RPM, but that was not WOT. I went up and ran it today,WOT, and got the following results.
 
 
Temperature today~ 70 F
Humidity- high, maybe 80%
RPM 5660
MP- didn't remember to look
Prop Catto  74 DIA x 88 pitch
Engine 93 13BREW N/A
Primary injectors - stock, 28 lb.
Secondary injectors  stock 40 lb.
PRSU RWS 2.85/1
RWS EM2 said it was making 161 hp. at 5660 RPM
Tail wheel was tied down, the brakes don't seem to hold at WOT even on dry cement.
 
My induction system was not hooked up, it was configured as shown in the photo.
I think, based on the above, that I might see 194 HP at 6800 RPM, which is 2386 RPM at the prop. Anyone who can calculate this more accurately, or shed more light, please go ahead and 'splain it to me.
In any case, I'm pretty sure it will be able to get off the ground.
 
The airworthiness inspection is completed, taxes are paid, and registration should arrive in the next few days. I'm still working on my tail wheel endorsement, I should have it by the time my instructor makes his next car payment, I hope. Also, trying to get some time in some tail wheel RV's. There are several people who have offered to take me up to get a feel for how they fly.
 
Steve Beckham and Mark Hatch graciously flew up to give the plane some scrutiny two weeks ago.
 
So, depending on how the stars line up, This plane might be airborne by the end of the month.
 
Brian Trubee


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