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Looking for a switch

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aadamson(at)highrf.com
Guest

Posted: Thu Sep 21, 2006 6:41 am Post subject: Looking for a switch

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

oldbob(at)BeechOwners.com
Guest

Posted: Thu Sep 21, 2006 7:01 am Post subject: Looking for a switch

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:



 	  Quote: 	
		   

 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.

aadamson(at)highrf.com
Guest

Posted: Thu Sep 21, 2006 7:18 am Post subject: Looking for a switch

In doing some more research, it looks like EATON may have what I need...

Anyone know of a EATON reseller?  They make the MilSpec version and a

regular version.  The Milspec is an MS27408-4M - the M is the designator for

the right type of lockout.  Or the regular version looks like an 8537k14m.



As a reference, here are their switches.

http://aerospace.eaton.com/pdfs/power/Switch_Catalog_With_Cover.pdf



If anyone has any further info, it would be helpful.



Thanks,

Alan 



--

N6030X(at)DaveMorris.com
Guest

Posted: Thu Sep 21, 2006 7:22 am Post subject: Looking for a switch

How about a 5 position rotary that you have to "accidentally" twist 

past 2 unused positions to get to high?



Dave



At 09:40 AM 9/21/2006, you wrote:

 	  Quote: 	
		  

<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

dennis.glaeser(at)eds.com
Guest

Posted: Thu Sep 21, 2006 7:52 am Post subject: Looking for a switch

The ON-ON-ON type of switch is the toughest to get without $pecial order - except for the S-10 from B&C which doesn't have locking.  

The most reasonably priced (~$12) locking switches I've found are the NKK S series - available from Digikey and Mouser.    

It's not what you want, but if you can live with an On-Off-On locking switch (S3AL), Digikey has some in stock:  

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=162095&Row=136164&Site=US   

NKK Datasheet:  

http://rocky.digikey.com/WebLib/NKK%20Switches/Web%20Data/SSeriesTogglesMedCap.pdf  

  

I've looked into locking switches a fair amount, and suspect to get exactly what you want will probably cost north of $40 (probably over 50), and require a few months on a special order.  The good news is that you'd be able to order locking to do what I think you want (no lock from Off to On - lock from On to Hi).  

Dennis Glaeser  

RV7A - Finishing kit     [quote][b]

Jim Baker

Joined: 30 Mar 2006
Posts: 181
Location: Sayre, PA

Posted: Thu Sep 21, 2006 8:11 am Post subject: Looking for a switch

 	  Quote: 	
		   


	


 	  Quote: 	
		   Personally, on the Continental

 fuel injection system, I see no problem with

 nonlocking switches for the boost pump.


	


I know my Bellanca Viking doesn't have a locking switch and, 

personally, wouldn't want one. Momentary inattention, and then 

the sputter of fuel exhaustion, prompts a quick stab at the low 

boost switch after switching tanks.



Jim Baker

580.788.2779

Elmore City, OK

brianpublic2(at)starband.
Guest

Posted: Thu Sep 21, 2006 9:22 am Post subject: Looking for a switch

I did a lot of looking at switches when I was doing my wiring layout (see

prev emails about Z-19).   I found a good selection of Honeywell and Eaton

switches at Allied.  http://alliedelec.com    I saved the PDF catalogs for

both brands & will send them to you

--

brianpublic2(at)starband.
Guest

Posted: Thu Sep 21, 2006 9:49 am Post subject: Looking for a switch

You might also consider a separate switch for the high boost



--

N6030X(at)DaveMorris.com
Guest

Posted: Thu Sep 21, 2006 10:46 am Post subject: Looking for a switch

Whenever I find myself looking for some kind of rare device, or 

putting something into the aircraft that nobody else seems to be 

putting in theirs, or looking for a very pricey component, I stop and 

ask myself, is this really necessary, or have I just designed 

something that is totally overkill?  Is there a reason why nobody 

else is doing it this way?  Am I really this far on the leading edge 

or have I made a booboo?



Dave Morris

At 10:50 AM 9/21/2006, you wrote:



 	  Quote: 	
		  The ON-ON-ON type of switch is the toughest to get without $pecial 

order - except for the S-10 from B&C which doesn't have locking.



The most reasonably priced (~$12) locking switches I've found are 

the NKK S series - available from Digikey and Mouser.



It's not what you want, but if you can live with an On-Off-On 

locking switch (S3AL), Digikey has some in stock:

<http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=162095&Row=136164&Site=US>http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=162095&Row=136164&Site=US 

NKK Datasheet:

<http://rocky.digikey.com/WebLib/NKK%20Switches/Web%20Data/SSeriesTogglesMedCap.pdf>http://rocky.digikey.com/WebLib/NKK%20Switches/Web%20Data/SSeriesTogglesMedCap.pdf 

I've looked into locking switches a fair amount, and suspect to get 

exactly what you want will probably cost north of $40 (probably over 

50), and require a few months on a special order.  The good news is 

that you'd be able to order locking to do what I think you want (no 

lock from Off to On - lock from On to Hi).



Dennis Glaeser

RV7A - Finishing kit

nuckollsr(at)cox.net
Guest

Posted: Thu Sep 21, 2006 11:16 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       >

      ---------------------------------------------------------

aadamson(at)highrf.com
Guest

Posted: Thu Sep 21, 2006 1:56 pm Post subject: Looking for a switch

Thanks Bob,  Glad we think alike... I may have described it slightly wrong,

but you were in the ball park.



I'd need either a 2TL1-10M or 2TL1-10P which translate to the MS27408-4M or

-4P.



I actually found one and they are pretty pricy at $65 ea!.  However, before

I go there, I'm gonna just try an ON-ON-ON from B&C and see if I can live

with "brain power" lockout.  If I have a problem, I'll get the "expensive"

switch.



As to the "why am I doing this this way" question.  Most wire two switches,

but in asking around, I could find no other reason for High Boost than

prime, so I was going to go with the ON-ON-(ON).  This is on a Cont IO-550

and some suggest that going to high boost on accident will flood out the

engine.  But then again, other suggest it wont.



Either way, I went with one switch position instead of two thinking I was

smarter than most and saving the panel space.  Perhaps, that bit me in the

bottom....



Oh, well, thanks all for the links, help and suggestions.  I believe I've

got a handle on this now.



Alan 



--

blackoaks(at)gmail.com
Guest

Posted: Thu Sep 21, 2006 6:19 pm Post subject: Looking for a switch

Or maybe a 1/2" length of a small brass hinge above the switch that must be lifted to allow you to select the Hi boost position....  Not elecgant but not $65 either.....   My .02



 	  Quote: 	
		   



If anyone has any further info, it would be helpful.



Thanks,

Alan

	


-- 

John McMahon

Lancair Super ES, N9637M  [quote][b]

blackoaks(at)gmail.com
Guest

Posted: Thu Sep 21, 2006 6:19 pm Post subject: Looking for a switch

Neither is my spelling!



On 9/21/06, John McMahon <blackoaks(at)gmail.com (blackoaks(at)gmail.com)> wrote: 	  Quote: 	
		   Or maybe a 1/2" length of a small brass hinge above the switch that must be lifted to allow you to select the Hi boost position....  Not elegant but not $65 either.....   My .02 



 	  Quote: 	
		   



If anyone has any further info, it would be helpful.



Thanks,

Alan

	


-- 



John McMahon

Lancair Super ES, N9637M  	


-- 

John McMahon

Lancair Super ES, N9637M  [quote][b]

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