|
|
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
>
>
>
>
> __________ Information from ESET NOD32 Antivirus, version of virus
> signature
> database 3267 (20080714) __________
>
> The message was checked by ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
>
> --
> Homepage: http://www.flyrotary.com/
> Archive and UnSub:
> http://mail.lancaironline.net:81/lists/flyrotary/List.html
>
--
Homepage: http://www.flyrotary.com/
Archive and UnSub:
http://mail.lancaironline.net:81/lists/flyrotary/List.html
__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3267 (20080714) __________
The message was checked by ESET NOD32 Antivirus.
http://www.eset.com
__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3267 (20080714) __________
The message was checked by ESET NOD32 Antivirus.
http://www.eset.com
|
|