G-force & light a/c
 

Take for example a simple C172 with gravity feed fuel tanks.

You are doing some training... say steep decents or recovery from unusual attitudes and you find yourself raining out of your seat and one or two things in the cockpit are rising to the ceeling.. in other words you are pulling some neg G.

What about the fuel.. surely it is rising to the top of the fuel tank also, therefore starving the fuel lines..... and thus stopping the engine? Why does this not happen in practice?

Cheers for any help with this one!

It does, if neg g sustained for long enough. For short periods, engine & carb "inertia" will sustain power.

try holding -veG a bit longer...it will stop!

was that my heart or the engine missing a beat.

There is sufficient fuel in the carb and fuel lines.

Carburettor engines have a problem with neg-G though. The Spitfire could not pull G above G-1 and this was a weakness exploted by ME109 chaps. they would go into an inverted steep turn or similar move to shake the Spitfires off their tails - the spit could not do this untill a small hole was drilled in the top of the carb (float chamber) to let pressure escape. (Please correct me if I'm wrong)

WF.

A quick fix devised by an illustrious female engineer, whose name escapes me. Someone will know it.

QDM

Hangar gossip teaches us that it was a Mrs Shilling, a RR. Tea-lady.

Wf.

You got the surname right WF, but little else I'm afraid.

Miss Beatrice "Tilly" Shilling, 1909-1990 was one of the first Lady Farnborough Boffins.

Her negative-g fix (a small metal disk with a hole in the middle) was nicknamed "Miss Shilling's Orifice" and was fitted to all Merlin equipped aircraft in fighter command in 1941 and remained there until RR came up with a better Carburettor.

Apparently the lady was also a very capable technician, raced motorcycles, when she married (an aerodynamicist named George Naylor) was presented with a set of stocks and dies by her colleagues, and was said to have turned her own wedding ring on a lathe from stainless steel.

Just before her retirement she was actively researching aquaplaning in the wake of the Munich / Manchester United accident.

Sorry I never met her, must have been a heck of a gal.

G

If Memory serves she roared around the country on a Brough Superior Motorcycle to supervise the installation of said gadget at the front line squadrons, this being considered a matter of some urgency at the time. Yes indeed a formidable lady!:ok:

They don't make the chicks like that nowadays.

All our women want to do is meet up to gossip, spend money on designer gear, argue about equal opportunities, have a career AND a child at the same time and buy the easiest to cook "quick meals" from Sainsbury's.

Shame really, I'm sure I should have been born 40 years earlier.

You've not met either Aerbabe or Whirlybird have you Toryboy? (Or for that matter Eve Jackson, Fiona Luckhurst or Caroline Grace - none PPruners so far as I know, but all of whom arguably make our resident capable ladies look like serious underachievers at times).

G

Well, that's what comes of listening to hangar gossip:)

Wonder who came up with the tea lady bit?:confused:

WF.

"All our women want to do is meet up to gossip, spend money on designer gear, argue about equal opportunities, have a career AND a child at the same time and buy the easiest to cook "quick meals" from Sainsbury's."

As opposed to the men who just want to hang around on pprune and indulge in some hangar gossip ;)

I gather that the favoured escape move for a 109 with an early Spitfire on its tail was to bunt over into a steep dive. The Spitfire pilot could only follow by rolling inverted and pulling, but in so doing would usually lose visual contact with the bad guy.

The tea lady rumour is probably attributable to a combination of basic sexism and aircrew ribaldry, as one can imagine pilots poking fun at the male boffins for failing to come up with a solution to the problem.

"I say, chaps" said P/O Prune, breezing into the mess with Kentish mud on his boots, "pranged another this morning, rum show, but guess what some popsy at the War House has come up with for chasing bunting jerries...top wheeze, eh? Oh, don't mind if I do, thanks awfully, skipper" .