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Ok, thanks, Tracy, food for thought.
I've actually thought about driving one of my
pumps using a PWM signal to vary its speed and therefore pressure as an
investigation into means of eliminating/minimizing chances of vapor lock
(similar to recent auto EFIs) and eliminating my small header
tank.
This would require me to isolate - say the
secondary injector fuel line to be fed by the PWM controlled pump and keep the
primary pump with tank as a back up until experiment is conclusive.
But, that adds components (pressure sensor, PWM generator) which could fail -
but presume it could be designed to fail so that pump puts out max
pressure (or some preset value). Hummmm.
Ed
----- Original Message -----
Sent: Friday, December 23, 2005 8:14
PM
Subject: [FlyRotary] Re: Question for
Tracy - was: Off Topic "Switch Placements"
Cold start on for the full lean condition is a good
idea. Punching the program button in mode 0 (Primer
function) will not work because the EC2 disables the primer when it
senses that the engine is running.
For full rich, Turning a set of injectors off would be good except
that it doubles the injection on the others at the same time. (I sense a
suggestion on the way for yet another switch to disable the injector doubling
function : )
Another thing to do in an emergency would be to cycle the fuel pump on
& off to lower the fuel pressure in order to lean the mixture. Or,
install a fuel pump controller to drop the pressure like some late model cars
do. (No! Just kidding!! even though it would work)
Tracy
Thanks for the info, Tracy. Until a
decision is make on alternatives, what might be good courses of action (in
order to get to a place to safely land)??
Full rich. Turn the secondary injectors
off - intermittently turn them all off if bogging.
Full Lean. Intermittently turn on cold
start or repeatedly punch program button in 0 mode
Wander around. Figure that on average it
will be "just" right {:>).
Ed A
----- Original Message -----
Sent: Friday, December 23, 2005 11:02
AM
Subject: [FlyRotary] Re: Question for
Tracy - was: Off Topic "Switch Placements"
Good question Perry.
Answer would depend on the exact nature of the
'open' . Open at ground end, hot end, or wiper.
Answers in order: mixture goes full rich, full lean, wanders around
at last set point. The pot used is a high rel part rated for 500,000
cycles but of course anything can fail.
Most pot failures are 'dead spots' where the wiper goes open at
a certain spot (usually near where it is used the most).
Mixture will drift at this point and proper pilot response would be
to move mixture to a slightly richer setting, land, get the pot replaced
before flying again. Thanks for the mental nudge, I need to add this
to the instruction manual.
I have pondered various fail safe strategies for this
scenario (for example, make the B controller fixed at midrange mixture)
but so far have not been satisfied with any of them. Anyone have
other ideas to be considered?
Tracy
----- Original Message -----
Sent: Thursday, December 22, 2005
4:50 PM
Subject: [FlyRotary] Question for
Tracy - was: Off Topic "Switch Placements"
This reminds me to ask a question to Tracy that wanders
through my brain
when there is no civilization in sight out the
cockpit windows.
Tracy: If the mixture pot fails (not all that
uncommon to get an open
failure in potentiometers) what does the EC2
firmware do to the mixture?
Perry
Casson
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