Mailing List flyrotary@lancaironline.net Message #50301
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: RE: [FlyRotary] fuel supply problem?
Date: Fri, 12 Mar 2010 23:02:00 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

Enough to get your heart pumping for sure.  Been there {:>)

 

Early in my flying days, I was in a similar type turn and was paying more attention to the buildings I had my wing tip anchored to than I should have been.  All of a sudden, the engine started unwinding with a vengeance.  I immediately leveled the air plane, where upon the engine caught again – but I was down to the last gallon or less – switched tanks and all was OK.  I suspected that perhaps my “coordinated” turn was not as coordinated as I had thought.

 

Both of my pumps can suck fuel from either tank, so can’t help you there.  I personally do not favor the one tank- one pump approach due to the fact if you did lose a pump – you could possibly lose access to a lot (perhaps a tank) of fuel.  No problem flying locally perhaps, but a different story if between the west coast and New Mexico {:>).  But, I realize there are advantages such as not needing a valve to switch tanks, but similar to having two CPUs for the fuel injectors either one of which can run the full set of injectors, I prefer both pumps having access to both tanks.

 

Also, just for the heck of it you might check the tank for water.  I flew into Shady Bend one time with my left tank dry.  Sat out through a few rain shows, took off the next day and landed at Waycross, GA and filled the left tank and topped of the right one.  About 30 minutes out, I decided to switch to the left tank, within seconds of switching the engine started surging.  Having learned my lesson about switching tanks on my 12 mile glide a few years ago, I immediately switched back to the other tank and thankfully, everything returned to normal.  I flew a bit further and go over a suitable air field and switched back to the left tank, again the surging – but I left it on this time an in about 20-30 seconds the surge disappeared. I thought I might have picked up some bad fuel – but not the case.

 

Yep, you got it – should have drain the tanks for water, which I failed to do that morning.  I can’t prove it was water, but I did discover my left tank cap was not sealing as it should and I suspect the empty tank accumulated a cup or less of water.  It settled to the bottom by the time I had flow 30 minutes and when I switched over all I got for the first 30 seconds or so was watery fuel which the engine did not like.

 

So be careful – Mike.  But, then that is what this test phase is all about – find out what might bite you while you are close to home.

 


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Friday, March 12, 2010 9:49 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] fuel supply problem?

 

Was out boring holes in the sky today trying to accumulate hours - finally a day off with no rain. About 2 hours into the flight, running on the left tank, and making a gentle left turn (maybe 20 - 30 degrees of bank), and the engine lost power. About 2 seconds later the engine monitor alarmed that the fuel pressure was below limits. By the time the alarm sounded I had already switched tanks and power was coming back up. My airplane is set up with 1 pump for each tank, so switching tanks actually means switching pumps too.

 

Needless to say I returned home immediately on the right tank and the airplane ran OK all the way back. Once on the ground I did a full power runup switching tanks repeatedly and everything was fine. I'm not certain how much fuel is in the left tank, I'm guessing about 5 gallons. I'll find out tomorrow when I top off the tanks.

 

The only thing I can guess is maybe the fuel in the tank drained away from the pickup in the turn? The turn was coordinated so in theory the pickup should have remained submerged. I might have to re-think the fuel system.

 

Mike Wills



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