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From: "George Lendich" <lendich@aanet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-3688913@logan.com>
Subject: Re: [FlyRotary] Re: 295cc vs 495 cc was [FlyRotary] responses to responses, not developing full power
Date: Sat, 20 Jun 2009 09:06:39 +1000
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Ed
I did the figurers again and 400 x 4 supports 245 hp at 79%Duty Cycle; 4 x 
440 at 71.5% DC; and 2 x 550 at 57.5 % DC.
The yellow injectors are between 78 DC( at best) and 88.5% (at worst).
So I have to agree with you and Tracy!
George(down under)

> Somewhere in that ball park, George.  I think between 440 -550 cc/min or 
> the
> stock N/A engine injectors is what the Ec2 was designed for.  Tracy added
> some features such as mode 6 to accommodate those who wanted to use
> different size injectors (within a limit).
>
> Smaller injectors can make a smoother idle for a car as they more finely
> control fuel flow at lower rpm, however, few that I am aware of idle their
> aircraft engines below 1200 rpm.  Both Tracy and I idle our older 13Bs at
> around 1800-2000 rpm.  So that benefit of a smaller injectors is rather 
> lost
> to our use.
>
> Plus a larger primary injector gives you that back up capability of 
> running
> on only one pair of injectors, only one size and type of injector to order
> or keep a spare on hand and little need to mess with Mode 6 a some of the
> advantages I see.
>
> But, part of this "hobby" is doing it "your way" - so certainly no problem
> seeing folks opt for smaller primary injectors, just not my personal
> preference.
>
> Ed
>
>
> Ed Anderson
>
> Rv-6A N494BW Rotary Powered
>
> Matthews, NC
>
> eanderson@carolina.rr.com
>
> http://www.andersonee.com
>
> http://www.dmack.net/mazda/index.html
>
> http://www.flyrotary.com/
>
> http://members.cox.net/rogersda/rotary/configs.htm#N494BW
>
> http://www.rotaryaviation.com/Rotorhead%20Truth.htm
>
> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
> Behalf Of George Lendich
> Sent: Friday, June 19, 2009 5:44 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: 295cc vs 495 cc was [FlyRotary] responses to
> responses, not developing full power
>
> Ed,
> 295cc + 495cc = 795cc, why not a couple of 400cc injectors as the figures
> suggest, what is the closest to 400cc injectors- is it the 440cc Tracy
> recommends?
>
> The engine won't be going over 7,200 rpm for most applications and the
> 495cc secondary Renesis is larger than our needs. I know larger is better
> for the higher RPM as it dispenses larger amounts of fuel over a shorter
> time, however for idle and low power their getting too big.
>
> So I figure for the situation of having them the same size, I wouldn't 
> have
> them bigger than the 440cc Tracy recommends.
> George (down under)
>
>> Don, if you are using stock Renesis (295 cc primary/495 cc secondary),
>> then
>> I am not surprised you find the running rough when switching to just the
>> secondary.  Here is why.
>>
>> Once you tune the EC2 to idle/low rpm - you are doing it before the EC2
>> stages, therefore the Ec2 is opening only the 295cc primary injectors and
>> you have tuned your engine (presumably) to run well at idle on the 
>> primary
>> injectors.  When you switch the primary injectors off and secondary
>> injectors on - the EC2 is still providing the same pulse duration
>> (assuming
>> engine manifold pressure, etc are the same) for the almost twice as large
>> secondary injectors as it did for the smaller primary injectors. Ergo, 
>> you
>> are feeding the engine almost twice the fuel (for the same engine
>> conditions) as you did when on the primary injectors.  The engine is
>> choking
>> on too much fuel.
>>
>> Those of use with the older 13Bs which basically had the same size
>> injectors
>> in primary and secondary roles OR those using the Renesis who have
>> replaced
>> the smaller 295 cc with the larger size secondary (which once again means
>> having same size injectors in both positions) can switch from primary to
>> secondary as the pulse duration is injecting essentially the same amount
>> of
>> fuel regardless of which pair you have turned on.
>>
>> Since Many of us have found that the 13B will produce almost full power 
>> on
>
>> a
>> single pair of 460/550 cc/min injectors - I personally favor replacing 
>> the
>> smaller 295 cc/min injectors with larger injectors.  Although two 295
>> cc/min
>> injectors will probably keep you airborne - its nice to have the option 
>> of
>> running on either pair.  But, as I said that is just my personal
>> preference.
>>
>> It sounds to me like the rough running on only secondary, the varying 
>> EGT,
>> etc, smacks of too much fuel for the operating conditions.  Try leaning 
>> it
>> more - you can't hurt the engine.
>>
>> Let us know how it goes
>>
>> Ed
>>
>>
>>
>> Ed Anderson
>>
>> Rv-6A N494BW Rotary Powered
>>
>> Matthews, NC
>>
>> eanderson@carolina.rr.com
>>
>> http://www.andersonee.com
>>
>> http://www.dmack.net/mazda/index.html
>>
>> http://www.flyrotary.com/
>>
>> http://members.cox.net/rogersda/rotary/configs.htm#N494BW
>>
>> http://www.rotaryaviation.com/Rotorhead%20Truth.htm
>>
>> -----Original Message-----
>> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
>> Behalf Of Don Wallker
>> Sent: Thursday, June 18, 2009 10:07 PM
>> To: Rotary motors in aircraft
>> Subject: [FlyRotary] responses to responses, not developing full power
>>
>>
>>
>>
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