Tom Smythe wrote:

Hi,

I'm the guy that was going to drop a 3 rotor into a Moose a while ago but, have been having second
thoughts as I just don't think the performance is what it could be (I also looked at the Aerocomp
birds but, again, think performance is lacking...).

So, I've undertaken designing a nice little six place plane of my own. Probably a composite bird
as I believe composites allow much more freedom and an aerodynamically clean airframe overall. To
that end, I still would like a powerplant in the 400HP range (like the Moose had with the latest
Russian radial but not the fuel hungry turbine on the Aerocomp models).

Given the ability of the rotary to handle quite a bit of boost, I've come up with the table below
(standard day):

                           2-Rotor     3-Rotor
                           13B         20B
 NA HP @ 6,500 RPM             195        290
 (guestimated)
 Fuel Flow (lbs/min)         1.4625      2.175
 Air Flow (ft^3/min) (59*   285.1875    424.125
 day)
 (air flow volume changes
 with temp, but mass
 stays the same and thus
 the MAP)
 400 HP Fuel Flow            3.0000      3.0000
 (lbs/min)
 400 HP Air Flow               585        585
 (ft^3/min)
 MAP @ Sea Level              2.05        1.38
 MAP @ 10,000'                3.02        2.03
 MAP @ 15,000'                3.64        2.45
 MAP @ 20,000'                4.46        3.00
 400 HP Air Flow               45          45
 (lbs/min)
 Recommended Turbocharger      T61        T61
 100% Power Ceiling          17,000'      26,000

The T61 is operating near the surge limit to achieve the HP required on the 13B. However, on the
20B, it's actually loafing along fairly nicely. Assuming the above numbers are correct, I'll be
planning the airframe around the 20B. Otherwise, it's back to the drawing board.

As an FYI, the airframe is a high wing design with fixed gear and a gross weight at 4,400 lbs
(give or take...) and usefull load of 1,800 lbs (600 lbs fuel). The initial design was created in
AirplanePDQ and is being evaluated in X-Plane (5.61).

Thanks,

tom

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