Still working numbers on the formulas. Just now I'm going backwards, taking prop-rpm, factoring in redrive to get e-rpm, *3 to get rotor rpm, factoring in CID and then scratching my head. Also, I could be wrong but I think 2800rpm for a 360 is excessive for normal operations. I'm too busy working formulas to try to verify just now.
Actually, Tom
The answer to your question is yes! Even I have achieved 6800 rpm in level flight - but, you need to ask with what gear box ratio and what prop. The 6800 rpm was with the 2.85:1 gear ratio and a 76x88 prop. Put on a low pitched short diameter prop and you can easily achieve 6000 rpm even with a 2.17:1 gear box. My top rpm with that set up was 6300 rpm and Tracy Crook got much higher - I think he achieved 7200 rpm.
Yes, all in level flight, gravity assist does not count {:>)
Now, if your induction/exhaust is not correct or if your Fuel MAP for your EFI is not set up right and ignition timing is not optimum, Or if you have a very draggy airframe which precludes unloading the prop and engine as you pick up airspeed, then certainly you can produce a lot less power. But, that's true of aircraft engines or rotaries.
Ed
----- Original Message -----
Sent: Thursday, February 10, 2005 10:52 AM
Subject: [FlyRotary] Re: : 13b vs 360 performance
Ed / Jerry,
I stand corrected. Let me say that 'the 13b power I see being achieved so far in NA 13b airplane installations seem to be less than what O-360 guys are getting'. After mounting props was anybody able to attain even 6000 rpm in their 13b NA aircraft installation, level-flight?
I assume you are talking about a 6000 rpm limited rotary vs a wide open
0-360. Run the rotary faster and thats the end of the story. Jerry
Ed Anderson wrote:
> Tom,
> I don't really think anyone can accurately make a generalization like
> that.
> From: Tom
> It's my understanding that NA non-renesis rotary installations
> produce less power than 360s, Perry Mick might have a word on this.
> Eric Ruttan wrote:
> A 360 Lyc does not produce the same power as a rotary.
> If true, then the Ellison card may not get enough air.
> If not true, then there is no real reason why the Ellison cannot feed a
> rotary.
>
> Ed, I understand your math, but even if the local inlet velocity is much
> higher, we dont care. the velocities adverage out to the same, as the
> volume of air = velocity * carb area.
>
> If the velocities are higher, the rotary consumes more air, and makes
> more power.
>
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