Hobbs Switch
 

Under the right wing of my 337H in the location of the normal inspecion port/disc just outboard of the wing strut is (or was) a small wind activated tab attached to a micro switch, that is I assume attaches to my hobbs meter for inflight recording. The small aluminum tab is now missing, and the tny microswitch it attached to has a cracked housing, which allowed the pin holding the tab to "fly off into the sunset". So I need a repolacement micro-switch with it's integrated flight activated tab. The switch is about 1" long, and 3/8" wide. I can't find any reference to it in my manuals, and talking to an A&P today, he said that there are a lot of different switches that have been used over the years.

Does anyone have an idea on what this particlarl swith is (number, etc) and where I might locate a replacement?

tks/Roger

I might have one. I took it off my skymaster, not sure if I threw it out though. I will check tomorrow. If I still have it, it yours. If you want a new one I'll get the part number off it for you, if I still have it.

I found what I have. I've attached a pic.

Thanks Tony

However that's not it. That pic looks more like a stall warning switch.

my broken part

Sorry I couldn't help. Good luck finding your part. :)

Mine failed on my 337G and I replaced it with a HONEYWELL S&C - 311SM703-T - MICRO SWITCH, which can be bought for under $7 at:

http://www.newark.com/honeywell-s-c/...pdt/dp/78K5282

It required some -- but minimal -- adjustment (cutting part of the long lever, I think).

Ernie

Thanks Ernie - I ordered one today

Roger:

I looked today at the airplane and in my 337G the adjustment was to cut the lever to the proper size and then glue/solder near the cut end a dime-size disk we made from aluminum.

If you need to fly before you fix it, just connect the two leads together without the switch; in that configuration, the Hobbs runs anytime the master is on rather than at speeds over ~ 40 MPH (when the airflow pushes against the disk to close the switch circuit).

Ernie