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If the injector switches are wired according to Tracy's instructions, then
your 13B NA engine will run just fine on either the primary or secondary
injector set. I have turned off one or the other pair numerous times and
flow at 95% of full power. IF your cold start circuit is wire correctly AND
you are using the correct two position (UP/DOWN) DPDT switches then, you do
not need to turn the cold start switch on when turning one of the injector
pairs off. This is because switching off either pair automatically engages
the cold start which doubles the injector timing.
BUT, if you are not using the correct DPDT switch (yes, there are more than
one type) you may encounter the need to separately activate the Cold Start
Switch. Here is why - a friend of mind was finding that he had to manually
turn on the cold start switch to enable the engine to run on one pair of
injectors. However, that is because, when he got the double pole double
throw switchs (DPDT), he got one with an UP, MIDDLE, and UPPER postion
rather than just an DPDT On/Off switch. This was what was causing his
problem. When throwing the switch down (for instance) to turn off a pair of
injectors it did not permit the switch to ground the opposing pins - which
is required. This left the cold start circuit ungrounded which mean he had
to physically throw the cold start swith to ground the circuit and causing
the EC2 to double the injector timing.
Following Tracy's wiring instructions exactly WITH the Up/Down, two
position DPDT you will not need to separately activate the Cold Start Switch
to run on one pair. When you use one of the terminals on the switch to turn
that injector pair off, that same switch action causes the opposite terminal
on that switch to ground the cold start circuit which causes the EC2 to
double the injector timing to the remaining pair of injectors and therefore
double their fuel flow.
Now, its true that the engine might momentarily sag when switching one pair
off as it apparently takes a fraction of second for the Ec2 to figure out
what it needs to do and then adjust the timing and the fuel flow and get the
additional fuel into the airstream. I found if you increase the mixture
just before you turn off one pair the engine does not stumble.
But, if you have to turn on your cold switch to run on one pair of
injectors, then either you are not using the appropriate DPDT switches or
you have a wiring mismatch.
Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
----- Original Message -----
From: "John Slade" <sladerj@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Monday, December 15, 2003 9:45 AM
Subject: [FlyRotary] Re: Fuel System
> > Since we are using two rotors is it possible to
> > split the fuel rail into two rails and have one of the returns plumbed
to
> the port
> > tank and the other plumbed to the starboard tank?
> I thought of doing this too since I was after total redundancy.
> The question becomes - "how well will the engine run (if at all) on one
half
> of the system?" You dont want failure of either system to be a problem or
> you've doubled you're risk.
> This will depend on the computer settings. Using cold start I suspect
it'll
> run reasonably well on either just primaries or just secondaries. Running
on
> one rotor only would probably not be a good idea. The other constraint is
> physical. At least with my 3rd gen engine with the primaries in the block
it
> would be simple to plumb the primaries and secondaries seperate. They're
> seperate already. You'd just need an extra regulator and a couple of extra
> pipes.
>
> In the end I decided to T the input just before the rail and switch the
> return with a solenoid.
> Regards,
> John Slade
>
>
> >> Homepage: http://www.flyrotary.com/
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
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