Steve,

Two dyno sheets from Daryl Drummond with BFSC for reference. One built for Pro formula Mazda and one for an individual according to Google.

Bobby

Hi there Le Roux.

I thought the BSFC would more realistically be around 0.55 for best power in the Renesis with 10:1 compression.
We burn PULP 95 unleaded.
So calculated might be in the ball park of - hp = 16.4 x 6.2 / 0.55 = 185hp at 6800 static
As the rpm rises on takeoff I would expect the hp to rise with rpm until the torque curve dives faster than the RPM rise.

What numbers are others seeing and how do they compare with Lycoming powered RV’s etc.


These are the numbers I got of the web for fuel weight (so not confirmed).
AU PULP 6.26 lb.gal Premium 95 Unleaded here in Western Aust
AU ULP 6.13 Standard 92 Unleaded here in Western Aust
AU Avgas 5.84
US Avgas 6.01

Cheers

Steve Izett

> On 20 Jun 2020, at 2:01 pm, Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:
>
> 
> Steve: From what i have read, you could use this formula to calculate horsepower ( or more or less)
>
> https://performancedevelopments.com/fuel-flow-calculations-for-horsepower/
>
> HP = (GPH) x 5.92 / 0.44 (BSFC)
>
> 16,4 (GPH) x 5.92 ( weight of 1 pound of fuel )
> devide by
> 0,44 Brake Specific Fuel Consumption BSFC.
>
> = 220 Hp
>
> I could be wrong
>
> Sent from my iPhone
> Le Roux Breytenbach
>
>
>
> Sent from my iPhone
> Le Roux Breytenbach
>> On 20 Jun 2020, at 04:49, Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
>>
>> Thanks Jeff and all
>>
>> Last flight (after playing around with Mode #1 tuning on the ground) the Primaries (4 port Red) were saturating at various times, indicated as Steve Boese reminded me, by the loss of RPM readouts (EM3 & Dynon Skyview) sensed from the Primary Injector line.
>> Do others with small Primaries have this issue or is it a Tuning issue?
>> ie. Getting modes # 3,6,2 right will spread the load between the Pri and Secondaries so the primaries don’t saturate?
>> I do have another set of the larger (Blue) secondary injectors that could replace the small red Primaries giving us 4 equal injectors, if this was helpful.
>> Do injectors have a sweet spot or better spray pattern at a particular band of duty cycle?
>>
>> We have an electric inflight adjustable prop which may make a difference from those with experience with FP props.
>>
>> On another note, I rechecked max fuel flow at static ~6800 rpm and 0.92 Lambda which I think is best power. Fuel Flow peeks at 16.4 Gal/hr.
>> It's a Renesis 4 Port with the stock exhaust header and resonator and a modified stock intake manifold which is basically shortened from 23.6” to 18.1”.
>> I had noted down that Tracy recommended 16” and Paul L 20” for the intake length.
>> What kind of hp do you think this might be producing and what are others seeing?
>>
>> How could we determine peak power/rpm? Could we use the airframe as a dyno in some way?
>> What about at WOT clean air and level, and adjust prop pitch/rpm for maximum airspeed.
>> I suppose is we kept the mixture constant we could look for highest fuel flow.
>> I’m trying ti ascertain the best rpm for takeoff.
>> At the moment I’m leaving the prop set fine and rpm is peaking at ~7500 on climb out.
>>
>> Your expertise and insights would be greatly appreciated.
>>
>> Steve Izett
>>
>>
>>
>>
>>
>>
>>
>>> On 19 Jun 2020, at 9:37 pm, Jeff Whaley jwhaley@datacast.com <flyrotary@lancaironline.net> wrote:
>>>
>>> I don't think you're missing anything Steve - my EC2 is the same : fixed at 20" ...
>>> It was originally 15.5" and could be set anywhere ... but after sent back to Tracy it is now 20" and cannot be changed.
>>> Jeff
>>>
>>> Hi people.
>>>
>>> I did some tuning this morning.
>>> But I couldn't get the staging point to change.
>>>
>>> I reset all modes to default.
>>> The built in default Stage Point on my EC2 seems to be ~20"
>>>
>>> Ran engine at the desired MAP, selected Mode #7 (I was aiming at 15.5") and pressed the Store Button.
>>> I also tried holding it for a few seconds.
>>> Staging Point stayed at ~20".
>>> What am I missing here?
>>>
>>> Steve Izett
>>>
>>> --
>>> Homepage: http://www.flyrotary.com/
>>> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
>>
>>
>> --
>> Homepage: http://www.flyrotary.com/
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