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I realized that between all this discussion I many have
provided comments that would mis-lead someone who may be looking at the Vertical
Power equipment.
To make a point, there are many ways, when using Vertical
Power, that you can do a specific task. You can allow software to drive a
function in an automatic fashion if you like, or you can create multiple
mechanical backup paths. In this specific instance. Yes, you could
put the boost pump on soft switches within the VP environment. *OR*, you
can put it on mechanical switches, external to the VP environment. Either
way, VP can be configured to know if a switch or other type
of mechanism is providing control to a specific
function.
This is one of the huge advantages in using a system
that monitors the electrical system and the airframe - just about anything
can be configured to be controlled or monitored by the VP
system. If configured correctly, you can have your cake
and eat it too.
Alan
Like I said, I certainly wish there was more supportive
data around to determine the best approach... I just offer some unqualified food
for thot... Looks like I succeeded :)
Dennis, yes you are correct, I'm certainly not
proposing any changes to the fuel system, just thinking outloud about the use of
boost pumps.
BTW, if you want to keep a single switch Eaton
makes a DPDT 3 position switch with a manual lockable position on one
side. So it works as a toggle to the middle position and then to go to the
3rd position, you'd have to pull out on the lever and move it to the 3rd
position and then it will be locked in that position until you pull the lever
out.
This way, you could use OFF and Low boost on the toggle
side, and if needed HIGH boost, locked if needed in an emergency. That's
what I was going to do until I went down the Vertical Power
route.
Alan
boost pump is on low; the engine keeps
idling.
According to Flying Magazine's
September 2004 Aftermath column, a Bonanza with a TCM TSIO-520 crashed
shortly after takeoff probably because the pilot inadvertently had the boost
pump in the high position. According to the article, full power operation
with the boost pump on high would not cause an appreciable loss of power, but
(according to the NTSB) when manifold pressure is reduced below 24 inches, the
engine will quit.
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