Fairchild Club Forum

'Hey group,
Anybody experience the following; recently did a couple of hours in
a newly purchased F24R46. I had a tail-dragger flight instructor in
the left seat. I had prepared myself by reading all I could about
the fuel system and its little "quirks". I had the all articles,
advise, etc. on proper procedures for switching tanks firmly planted
in my mind. Like not switching tanks just before takeoff, correct
procedure on switching tanks in flight, correct procedure for
switching tanks if you ever run one dry, etc. But we got an
unexpected surprise.
After taking off and cruising for about an hour on the right tank, I
switched to the left tank. That went well as we started our descent
toward the airport. Everything running smooth as butter. Descent
checks were completed with full application of Carb. Heat. My
pattern was a bit sloppy so I pulled the nose up a tad to gain a
little altitude. The engine coughed, sputtered, shook, and damn near
quit. An immediate switch to the other tank smoothed things out.
What the hell here! Any Ideas? We had taken off with full tanks
about an hour earlier. Thanks for any advise.
Tom
Hanford, Ca'

'Tom:

> Descent checks were completed with full application of Carb. Heat. My
> pattern was a bit sloppy so I pulled the nose up a tad to gain a
> little altitude. The engine coughed, sputtered, shook, and damn near
> quit. An immediate switch to the other tank smoothed things out.
> What the hell here! Any Ideas… We had taken off with full tanks
> about an hour earlier. Thanks for any advise.

Fortunately I havent encountered this. Ideas, although perhaps not
good ones:

Debris or contamination blocking a fuel port? Could be sloshing around
and therefore intermittent.

An obstructed fuel cap vent?

Perhaps a little water? I assume its not cold enough for ice in the
tank where you are.

Did it happen soon after the application of carb heat? Carb icing?

Did you verify the fuel quantity remaining in that tank after landing?

Good luck.

:Dan Michael
:NC81323'

'

> checks were completed with full application of Carb. Heat. My
> pattern was a bit sloppy so I pulled the nose up a tad to gain a
> little altitude. The engine coughed, sputtered, shook, and damn

near

> quit. An immediate switch to the other tank smoothed things out.
> What the hell here! Any Ideas? We had taken off with full tanks
> about an hour earlier. Thanks for any advise.
> Tom
> Hanford, Ca

Tom,
I have never had this problem (in 400+ hours). If it occured right
after carb heat, I would suspect carb ice. If there was some time
between carb heat and nose up, I would suspect something with the
fuel system. The pick-up on the Fairchild is NOT at the rear of the
tank, and can suck air in a 'real low fuel - nose up' situation.
Remember though, that it is a long ways from the fuel tank to the
carburator, and if it did suck air (or water) it would be a number
of seconds before the coughing.

I think that lack of fuel will cause the Ranger to stop fairly
quietly, without much of a cough. I would suspect contamination in
the tank.

How much fuel was in that tank? Did you drain the sump prior to
flight? Did you drain it after the excitement? Did you look into
the tank for debris?

If I couldn't find anything in the tank, I might put a little gas in
that tank, and fill the other one, and go to altitude and try to
replicate the event. You may have a hole in the pickup, that causes
it to suck air in a 'some fuel - nose up' situation.

You are fortunat that you did not do damage to yourself or the
airplane. Don't give up 'til you have an answer.

Bob Waldron
1939 Fairchild 24 K
Stillwater, MN'

'Thanks Guy's,
I live for these little problems. Starting with the basics (fuel or
spark problem) I'm beginning with fuel delivery. I just think an
engine can't run better than the fuel system is capable of
delivering.I did notice on a recent complete fuel drain of
both tanks (reweigh) and after topping both tanks the left tank had
a noticeable weaker flow at the gasolater. Given that, and that the
rough running engine was cured immediately by a tank switch, leads
me to believe in a flow problem. I'm starting at the fuel caps and
chasing it all the way to the carburetor. My maintenance manual
shows fuel screens at the fuel lines as they leave the tank. The
previous owner/restorer said there is none. I dunno, think I'll
check it anyway.
Tom (how come these message don't post like you type 'em)?'