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From: "George Lendich" <lendich@aanet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-3678405@logan.com>
Subject: Re: [FlyRotary] Re: Injectors quandary.
Date: Thu, 11 Jun 2009 08:47:30 +1000
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 Chris,
Using Ed Anderson's calculations, my figures indicate at 7,200 and 100 % VE 
(@ best power 12.65:1) = 1 lb fuel min or 60 lb fuel an Hr ( 10 Gal hr).- 
each rotor, At 6,000 rpm it's only .8338 lb min or 50 lb hr( 8.3 gal.hr).

Using the guide in the below mentioned web site.
60 lb/hr  x 2.04 =122.4 hp each rotor.
60 lb/hr x 10.5 = 630 cc min.
80% of  650 cc min injector = 520 ccmin.

Seems like there is plenty of capacity using 2 x 650cc injectors, maybe even 
too much, considering pulse width at low RPM.

Are the injectors size ( flow) calculated at 100% duty cycle or 80% duty 
cycle? I may be wrong but it appears you could get away with 2 x 400 cc min 
( 800 x 80% = 640cc)

George ( down under)

> Chris,
>
>    There was a lot of traffic on this subject in 2003.  IIRC Ed
> Anderson was/is using MSD injectors (2012?).  Dunno if they
> will fit the Mistral manifold, though.
>
>   Some interesting info here:
> http://www.robietherobot.com/Storm/fuelinjectorguide.htm
>
> and here:
> http://www.importperformanceparts.net/imports/accelfuelinj-choose.html
>
> HTH,
> Dale R.
>
>
>> -----Original Message-----
>> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On 
>> Behalf Of Christopher Barber
>> Sent: Wednesday, June 10, 2009 2:38 PM
>> To: Rotary motors in aircraft
>> Subject: [FlyRotary] Injectors quandary.
>>
>> The list is WAY too quiet. So, I thought I would pose this 
>> concern/question.
>>
>> I am wanting to get new/rebuilt injectors.  I tried to get some a while 
>> back and ordered 4 Mazda injectors.  It was at this time I discovered 
>> that the stock Mazda injectors do NOT fit the Mistral intake.  My former 
>> build helper originally found the injectors I have been using.  The are 
>> seriously mismatched at about 550 cfm and 1600 cfm.  I know the EC2 can 
>> compensate (perhaps with some difficulty due to the extreme difference), 
>> but I am wanting to replace them all with about 550ish injectors. 
>> Perhaps it will help some of my leaning issues, perhaps not..
>>
>> I am having a couple of issues.  First, getting the right PHYSICAL size. 
>> While the ones I am using in the Mistral Intake look a great deal like 
>> the Mazda injectors, they are different in physical dimensions.  The ones 
>> I have come back with a Chrysler (Deko) and Ford Part numbers, but seem 
>> to be very old part numbers have been difficult to find online (my local 
>> auto shop and speed shop has been no help...I seem to know more than they 
>> do about the topic even though they did try to help).  Are there 
>> "standard" known physical types with some kind of verbiage that will 
>> allow me to get the proper fit?  Or do I use my calipers, go for the 
>> couple of sets I have found with dimensional drawings, order them and 
>> hope for the proper fit?  I just do not know the "standards" used and I 
>> yet been unable to find the answer online....gee, I may have to resort to 
>> live persons in an auto electrical shop <g>.  Some of the injectors seems 
>> short and stubby and some long and skinny...some, indistinguishable to 
>> the untrained eye, like the different ones I have now.
>>
>> I know, due to my ignorance, I may be making this harder than it is, but 
>> hey, it is part of the learning.
>>
>> SECOND.  Since I am ordering new injectors anyway, I am curious about the 
>> impedance.  The current ones are low impedance.  Thus, I am using the 
>> resistors in series with each injector.  I know the EC2 does not seem to 
>> mind this at all, however, since I am replacing them, is it wise to 
>> remove this minor failure point (the connections to the resistors etc) 
>> and buy high impedance injectors and remove the resistors?  Does one have 
>> a significant advantage over the other?  Seems if you can reduce the 
>> parts count (heh, like in the rotary), it may be better.
>>
>> Thanks guys.  Hope this helps pick up list activity a bit too.
>>
>> All the best,
>>
>> Chris
>> Houston
>>
>>
>
>
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