Frans,
Fuel injection has been used on the predator for 300,000 hours. If you talk
to any mechanics that worked on the aircraft before 2001 and after, they w
ill all tell you that fuel injection increases performance, much less maint
enance, longevity, throttle response, reduces vibration 1/2- 2/3, fuel cons
umption ect. All my systems use a fuel rail. If air gets into the fuel rail
, it just circulates out and back to the tank via the fuel pressure regulat
or. Fuel injection is under 40psi of pressure, you will never get vapor (du
e to the-fuel vaporizing)-in the fuel system. If you are getting really
low on fuel, you might suck some air, and then some fuel, then some more a
ir. The air will drop your fuel pressure untell the pump sucks more fuel. O
nce the fuel gets flowing again, the air will be pushed out of the fuel sys
tem in just a second or two.--My fuel systems have been modeled paralle
l to what the military has done. If it was a- problem, they would have
addressed it. the predator is as tight of a cowling as you can get one, an
d in a pusher configuration.
Thanks everyone for your support
Jason
--- On Wed, 5/13/09, Frans Veldman <frans@paardnatuurlijk.nl> wrote:
From: Frans Veldman <frans@paardnatuurlijk.nl>
Subject: Re: Europa-List: 914 Fuel Injected Update & Opinion
Date: Wednesday, May 13, 2009, 1:27 PM
Curtis Jaussi wrote:
> Lots of good questions.- I can address some of them.- Jason is well a
ware of
> the problem of potential air in the fuel and has designed the fuel flow
> through the system and back to the tank so that any air should be pumped
on
> through quite quickly.- This part makes sense to me.
Yes, but it is still possible that some air will make it into the
injectors. And then? Furthermore, it doesn't has to be air, it can also
be vaporized fuel. Although any engine hates that, a fuel injected
engine especially hates it. With the tight and warm Europa cowling, and
high altitude capability, and the use of Mogas, I think some fuel vapor
can hardly be avoided.
Also, this system will make it impossible to run a tank dry, before
switching to the reserve side. So, this poses the problem that one has
to decide at what level to switch over. 5 Liters at least remaining
seems to be the minimum to me, and one should not forget to switch over
in time. (if the reminder is in the form of a sputtering engine, like it
normally is, it is probably to late for the fuel injection system). With
5 liters, one has about 10 minutes left (considering the fact that the
very last liter will probably have so much air in it that it will be
unusable anyway). This will cut the usable amount of fuel considerably.
Any fuel savings due to the fuel injection is offset by the fact that
you can't risk to run the main side of the tank dry, so effectively you
can't increase the endurance.
>- As for redundency, it
> is totally redundant with two complete systems: two fuel pumps, two sets
of
> injectors, two sets of sensors,separate electrical systems, etc.- Only
one
> system is in operation at one time and you manually switch from one to th
e
> other if needed.
Ok, sounds good.
I think that Jason will probably draw more customers if he puts all this
kind of information on his website. I could do with less pictures.
Some more information about an upgrade kit for existing 914's would be
great as well.
--
Frans Veldman
le, List Admin.
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