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Need... is a relative term.
First of all. the EC2 has (or had at one time) a sneak circuit that will power the EC2 via the injector power wires if they are not switched OFF when the engine and EC2 are intended to be off. So a minimum of one injector circuit disable switch is required.. switch, breaker or both.
Second, if that ONE disable switch failed you'd lose ALL the injectors and have a true single point failure mode.
Third, if you have a problem with an individual injector, you can shut it (and its paired partner down), and a wiring mechanism is in place to cause the EC2 to compensate by doubling or nearly doubling the fuel flow (within the capacity of the injectors) through the remaining injector bank/paired injectors. This can permit the pilot to work around an unbalanced fuel flow problem and turn it into a balanced fuel flow condition (balanced power generation between the two rotors) until a timely and preferably minimally eventful landing can be made for repair and troubleshooting.
Given that the installation I have REQUIRES that I have at least one injector bank disable, I choose to WANT more than one disable circuit with the injectors divided evenly between them.
Dave
Michael LaFleur wrote:
Is there a reason you need an injector disable switch?
Just looks like another failure point and an increase in risk.
Mike LaFleur
----- Original Message ----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Thursday, May 31, 2007 8:19:39 AM
Subject: [FlyRotary] Re: It is ALIVE!!! First Start in Houston
Dave,
Congradulations on first start!!! It is a real rush to hear your baby breathe its first breath. As for the "Disable" switches, Tracy and I had a discussion on this issue just a few weeks back. He assured me that I wasn't the only one confused by the logic of the disable switches. He now recommends that UP be ON (normal operation), and DOWN be DISABLE. My little pea brain understands that.
Glad you figured it out so quickly. Mark S.
On 5/30/07, *David Staten* <Dastaten@earthlink.net <mailto:Dastaten@earthlink.net>> wrote:
We are prolly gonna go with UP for ON and DOWN for OFF. That seems
to be
the simplest for us southerners :)
Yea.. it was the injector power switches.
Dave
Bob White wrote:
>Congratulations Dave and Chris. Brings back memories of my first
>engine start. Are the switches you had to turn over the injector
>disable switches? If that was my diagram, up is for _disable_
and down
>is for run! As long as they work the way you want that's the way to
>wire them. :)
>
>Bob W.
>
>
>On Wed, 30 May 2007 22:10:06 -0500
>"Christopher Barber" <CBarber@TexasAttorney.net
<mailto:CBarber@TexasAttorney.net>> wrote:
>
>
>
>>Oh, and for those playing along, we did install the check valve
properly <g>. So far only a minor oil leak from a plug in the
engine Dave thinks he may have just snugged in by hand and forgot
to tell me to get back to and a small coolent leak on a temporay
hose connection. Really, really small in both cases....almost non
issues. FWIW.
>>
>>Thanks again for y'all's support and well wishes.
>>
>>All the best,
>>
>>Chris
>>Houston, Texas
>>Ellington Field (EFD)
>>
>> ----- Original Message -----
>> From: Christopher Barber
>> To: Rotary motors in aircraft
>> Sent: Wednesday, May 30, 2007 9:54 PM
>> Subject: [FlyRotary] It is ALIVE!!! First Start in Houston
>>
>>
>> It actually started. We turned it off and it started
again. WAHOOOOO. But a mear wahoooo doesn't quite express the
amazing feeling and sense of accomplisment of first engine start
of the 2nd gen, turbo housing 13b.
>>
>> David and I rebuilt it about 1.5 years ago. Dave did most the
teardown, cleaning, measureing tolerance etc and we both rebuilt
it following along Bruce T's video and the Haynes shop
manual. Dave final install on the CC engine mount and Tracy's
PSRU. I ran the wires, hoses...and the rest. A true joint effort.
>>
>> We tried last night to no avail. Turns out when I wired the
injector switches based on a great diagram from the Flyrotary
list, the illustration stated "top" and I installed that end up
with the swithes being up when on. However, when I was checking
my wires this pm I noticed that power was coming through the
switch when the switch was down.....doh! So, I turned them over
and rechecked the rest of my wires and grounds.
>>
>> In a damn optomistic gesture while in a pessimistic mood, my
hangar mate, Richard Sessions (who is restoring a VariEZ) and my
S/O, Jana and I pushed the tale of the Velocity out the hangar
door (of course it started sprinkling <g>) (Dave was still at
work). We took basic security procedures, ie showing Jana how to
use the fire estingusher. I turned on the switches (including the
now correclty mounted injector switches), turned on the primary
fuel pump, hit the starter button and DAMN, it
fired.........SCARED THE HELL out of us.......you should have seen
my two Cairn Terriers (Winston and Madison) head for the hills
(well, Houston has no hills, but y'all get the idea). We kinda
looked at each other in a mixed shock and amazement and checke
that we didn't blow anything off. We actually mixed fuel, air,
compression and spark and got combustion.....who'ed of thunk it?
>>
>> We waited for the portable battery charger/starter to bring
the battery back up and tried again. Switches up, Pumps on, press
the starter button......damn, it sputtered and started (after
some cranking). It started to rev really fast, or seeminly so, so
I brought the throttle to closed, which didn't stop it, so I cut
the fuel pump and it stopped. Go figure.
>>
>> Well, we did this a few more times, never running it too long
since we do not yet have sensors on it yet. Also, Dave got off
work and came by to join the fun. Just the fact it actually ran
was great. Now that Tracy should be getting back into town, we
should be able to order the correct sensors to replace the ones
that were missplaced along the way.
>>
>> Not quite sure what to work on now. Obviously we will want to
smooth it out and get it to start easily. It is currently running
better on B than A. I may have inavertanly changed someting on A
while messing with it during start sessions (may need to reset
A...donno yet). I think I will now try to start to clean up the
wiring so as to make it easier to manipulate the stuff in the
cabin. Righ now the panel is laying where the front seats should
be. So this may be a good starting point while waiting for
sensors that will let me know I am not ruining my new engine.
>>
>> Y'all's support and words of wisdom, along with Tracy Crooks
great products it what helped make this a reality. Thanks for
being there. NOW THE REAL WORK (read that as fun) BEGINS.
>>
>> Dave will be posting a much more technical account
soon....heck, I bet we both rushed home so we could annouce it to
the world.
>>
>> Thanks.
>>
>> All the best,
>>
>> Chris
>> Velocity N17010
>> w/ a Rotary 13b...that actually runs.
>>
>>
>
>
>
>
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