I met you at the Wisconsin Dells airport some years ago. My father and I have just started flying our Tailwind with the 13B. The power is great.


Thanks,

Dave Williams

Wow that was a long time ago.

Please send some pictures with the cowl off.

Paul Lamar

-------------------------------------------------------------------------------------------

Very unusual intake manifold. What is the rational for that manifold?

  From the looks of it appears to be a simple rectangular box with holes
for the ports.

By way of judging the power what is the top speed, engine RPM and gear
box ratio?

Paul Lamar


Similar intake concept as mine, wonder what RPM that rotary is putting out?



Bob Forbes

Not exactly Bob.

BTW how is the Helmholtz  spectrum analyser project coming?

Paul Lamar


Hello Paul,

From my world of Jaguar intake manifold development, long runners
are for low rpm torque enhancement. At high rpm, the long runners
are just drag ,thus less flow. In an airplane low rpm torque isn't
needed.  Yes the intake is just a box, creating a plenum to balance
the ports. Since it is fuel injected, there are no issues of
fuel\air separation. I have not topped out the airplane yet. The only
power indicator I can state is 5,500 rpm \ full throttle = 120 mph
indicated climb speed at 2,000 ft. per minute.

Hello Paul,

Wow! No.

Dave Williams
Thanks,
Dave Williams

That is an extraordinary climb rate for a rotary at 5,500 RPM.
Double check that climb rate.

The rotary does not make much power at 5,500 RPM

What is the gear box ratio ?  That is modest RPM for even for
an early Tracy  2.12:1 gear box.

What is your fuel burn?

Typical Tailwind Performance

   Maximum speed: 200 mph ( km/h)
   Range: 600 miles (970 km)
   Service ceiling: 16,000 ft (4,900 m)
   Rate of climb: 900 ft/min (4.6 m/s)


Here is how intake pipe diameter and length affect a Jaguar
six cylinder engine torque curves. HP = torque times RPM divided
by a 5252 constant.  HP=T x RPM/5252

The Jaguar does not breathe as well as the rotary at high RPM due
to the intake valves. However a 8 inch pipe length is 5% more power at 5900
RPM in a jaguar engine.

Also please read these files.
http://www.rotaryeng.net/intake.html

Do you have any pictures of the lower part of the engine?

Paul Lamar

Hello Paul,

Wow! No.

Dave Williams


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