Leonard,

     A simple electronic pulse generator using a 555 IC timer chip driving a
Darlington Power transistor could be used to pulse an injector on and off.
You could either experiment with the pulse duration and rate to provide fuel
flow at a certain rpm or perhaps a simple potentiometer that you could use
to vary pulse rate of the 555.  I would probably set the pulse width to
ensure that the injector is at least 80% of its flow rate when pulsed
(probably between 4 and 8 milliseconds), then use the potentometer to vary
the rate at which it is pulsed.  That way as you varied your throttle
setting you would manual vary the pulse rate to provide the fuel required
for that rpm.

However, it would probably not idle worth spit, but in the case of getting
home that might not matter too much.
If you have not yet selected an EFI computer, I might suggest looking at the
EC2 offered by Tracy Crook of Real World Solutions, it has two redundant
computers and sensor sets, one dies, you flick a switch and fly just fine
one the other.  Cost around $900.

Ed Anderson

----- Original Message -----
From: "Marvin Kaye" <marv@lancaironline.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, February 27, 2003 6:45 PM
Subject: [FlyRotary] Re: Injector Sizing


> Posted for "Leonard Garceau" <lhgcpg@westriv.com>:
>
> I have a question:  As a backup system for my autoconversion (fuel) I'm
> considering one large injector into the manifold to spray fuel to keep the
> engine running until landing.  What does it take to fire a fuel injector
50
> lb/hr 12 ohm saturated circuit driver type?  Would be feasible to use it
as a
> backup fuel delivery?  Is the triggering complicated or can a simple
> electronics do the job?
>
> Leonard
>
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