nuckollsr(at)cox.net
Guest
|
 Posted: Mon Nov 06, 2006 3:13 am Post subject: Looking for a switch |
 |
|
Alan,
The functionality you're asking for is provided by a
Microswitch 2TL1-10N or 2TL-10L (either locking option
will work, you just need to re-wire). These translate to
MS27408-4N and MS27408-4L.
http://www.aeroelectric.com/Mfgr_Data/Switches/tl_series.pdf
Having said that, I agree with Bob's suggestion that you
investigate the real risks for inadvertent positioning
of the boost pump switch. I've flown a number of aircraft
with OFF-LO-HI boost switches . . . none of them offered
any sort of "lockout" provisions.
These switches will not be easy to find . . . they're not
a common catalog item.
Bob . . .
| Quote: |
<oldbob(at)beechowners.com>
Good Morning Alan,
Once again, I am probably venturing where my knowledge
is insufficient, but here goes any way!
What engine are you running?
We often have high and low boost pump positions on our
fuel injected Continental engines. It is true that
high boost will kill an engine being operated at low
power, but if the throttle is wide open and the RPM
good and high, high boost may not even be noticed!
The fuel pressures are not additive. The boost pump
only puts out a bit more pressure than the engine pump
does at high power. In some cases, it is even a bit
less, though still adequate to operate the engine at
full power in the case of an engine driven pump
failure. If you are operating at normal cruise powers
and the high boost is selected, the engine may get a
bit rough, but the power loss will be minimal and the
roughness will get your attention in plenty of time to
take corrective action. Personally, on the Continental
fuel injection system, I see no problem with
nonlocking switches for the boost pump.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Stearman N3977A
Downers Grove, IL
LL22
--- "Alan K. Adamson" <aadamson(at)highrf.com> wrote:
>
> Adamson" <aadamson(at)highrf.com>
>
> I'm looking for a locking type switch to be used to
> control 2 positions on a
> fuel pump (low boost and high boost). I need the
> configuration to support
> the down position to be off, the middle to be low
> boost on, and the top
> position to be high boost on, with a lockout between
> low and high boost.
>
> I've done a bit of searching, but so far, haven't
> been able to find what I
> need. Hoping someone here might have seen what I've
> described. I had
> originally thot of using an S700-2-50 as I thought I
> only needed high boost
> for prime. However, in talking with other pilots,
> it now has come to my
> attention that High boost needs to be switchable in
> the event of engine
> driven fuel pump failure and can't simply be
> momentary. The reason I can't
> use a 3 position without lockout, is that low boost
> is normally switched on
> at or above 10K and if you accidentally switched to
> high boost, you'd drown
> the engine.
>
> Any help would be appreciated.... In the morass of
> switches that exist, even
> a good source of a manufacturer and I'll do the leg
> work would be helpful.
>
> Thanks in advance,
> Alan
>
>
>
>
>
> browse
> Subscriptions page,
> FAQ,
> http://www.matronics.com/Navigator?AeroElectric-List
>
> Web Forums!
>
>
> Admin.
>
>
>
>
>
--
-- incoming mail is certified Virus Free.
Checked by AVG Anti-Virus.
|
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
