I have been working too hard lately what with all the variations
of 3D intake manifolds layouts I have been doing for Jerry.
I need somebody that knows how to do spread sheets to take the
two lowest dyno curves off this torque chart and convert them
to HP curves in gif or jpg format. This is the best torque
information we have on 13B geometry peripheral port engines.
The HP formula is torque times RPM divided by 5252 of course.
Paul Lamar
Here is a plot of the lower curve using the data points I
interpolated. These are the XY points I used if you want to double
check for accuracy.
I'm still working on curve +150
RPM X 1000 Torque (N-m) ft-lb HP
4 425 313.46 238.74
4.28 450 331.9 270.48
4.5 461.5 340.38 291.65
5 476.9 351.74 334.87
5.45 500 368.78 382.68
5.5 502.7 370.77 388.28
5.78 550 405.66 446.44
6 589.5 434.79 496.72
6.1 600 442.54 513.99
6.3 604.2 445.64 534.56
6.5 600 442.54 547.69
6.67 589.5 434.79 552.18
6.83 573.7 423.14 550.27
6.93 550 405.66 535.27
--
http://www.bob-white.com
N93BD - Rotary Powered BD-4 (soon)
Further along to perfect Bob.
Plot another 1000 RPM and we will have it.
Tracy is running a 73 inch prop and he is getting 7300 to 7400.
With a smaller dia. prop and a 2.85:1 PSRU we could be looking at 8000
RPM with P-ports.
Paul Lamar
Bob White wrote:
Here is the +150 data. Matt's is prettier. :)
My interpolations form your second gif file and calculated HP.
RPM X 1000 Torque (N-m) ft-lb HP
6.02 560 413.03 473.43
6.25 593.5 437.74 520.92
6.67 611.25 450.83 572.56
6.93 597.5 440.69 581.49
7.08 581.75 429.08 578.42
7.27 553.75 408.43 565.36
Bob White
http://www.bob-white.com
N93BD - Rotary Powered BD-4 (soon)
If you overly these two (175 and 150) I think you will be able to see the
effects of skin friction drag in the intake pipes. The 150 being shorter
and less draggy than the 175 while still giving good power at 6000 RPM.
Namely about 235 HP. I don't want to put too much credence in this
as experimental error could be a factor. Also cruise BSFC could be hurt
if the pipes are too short. We will never know until we get a dyno.
Paul Lamar
I took the liberty of adding the 2 rotor HP numbers on the right of Bob's
chart in case someone though we were getting 600 HP out of a two rotor :)
BTW the 175 refers to an 18 inch long manifold runner and the 150 is
an inch shorter roughly. Very sensitive in this area. The 175 mm is added
to the the fixed lenght of about 10 inches.
I am really excited about the potential of the P-port and the 2.85:1 gear box
in aircraft use. To get the RPM up to realize these HP numbers IMHO we need
to use a modest diameter prop with wider blades. More on this shortly.
A square law function curve plotted on these charts will show the effect of prop
load. Prop load HP is at least a square law and maybe as much as a cube law.
A series of these curves overlaid on these charts could represent different
prop pitches.
Paul Lamar
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