Mailing List flyrotary@lancaironline.net Message #52576
From: Tracy <tracy@rotaryaviation.com>
Sender: <rwstracy@gmail.com>
Subject: Re: [FlyRotary] Re: The Case For Turbocharging
Date: Sun, 17 Oct 2010 16:32:53 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
" I simply calculated the prop power draw 180HP / 2700RPM = 200HP / 3000 RPM."

Hmmm..., that prop power equation might be a problem.   Power absorbed by a fixed pitch prop varies as the CUBE of RPM,  far from a linear function.

Tracy

On Sun, Oct 17, 2010 at 1:40 PM, <shipchief@aol.com> wrote:
Kelly:
Maybe I'm a bonehead, but those zip files didn't include anything readable for me....
On the other hand, I'm using a Turbo on my RV-8 prject, so I'm in as far as selecting a turbo.
I finally decided to use a turbo because of Tracy's muffler experiments. I have a Turbo engine, with the open exhaust ports, so the sound pressure is very high and would require an extra strong and tough exhaust system (heavy). So I decided to use that weight in the form of a Turbo to knock the most vicious element form the exhaust noise. I hope for a higher rate of climb as a result of the increased power potential.
I realize that all engines have a sweet spot that would be best for cruise and range, which would co-incide with the engine torque peak RPM and an airspeed less than Vne, so sustained high turbo boost is not practical or desired unless 25 gallons per hour fuel flow is expected! That's a pretty short flight with 42 gallons total fuel aboard.
I set my goals to a more attainable level, with a prop that should draw about 200 HP at 6500 RPM. It's a left hand turning equivalent of the prop for RV-8s with a 180 HP O-360 Lycoming. I have Tracy's RD-1 2.19:1 4 planet gear, so I don't plan to abuse it past the 200 HP limit he has established. I simply calculated the prop power draw 180HP / 2700RPM = 200HP / 3000 RPM.
By the way, for you prop chord measuring guys, it's a CATTO 2 blade 68x74 prop, with the greatest chord about 6-3/16" falling from 16" thru 20" in from the tip, which is right in front of the cowl cheek edge.
This last week I put the wings on and set the incidence, made the fuel tank attach brackets and fit the flaps & fairings. Now the wings are back off, getting the fairing platenuts etc.
I'm not that far from taking the whole caboodle to the airport!!
-----Original Message-----
From: Kelly Troyer <keltro@att.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sun, Oct 17, 2010 9:50 am
Subject: [FlyRotary] The Case For Turbocharging

Group,
    Perhaps of interest to those us interested in Turbocharging our projects..........It
is from the "SDS" website.............
 
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo

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