Spitfire engine problem

[Von Falke]

Hi!

This is my first post here and i have one question.
I heard some time ago, by someone, that the early Spitfires had problem when flying inverted, because of the fuelpump not being able to work properly.
Does anyone know if that was true?
If it was true, when did this problem get mended?

Thank you!

 

[FLYBOYJ]

It was the carburetor that would cause the engine to quit.

 

[bomber]

I think it's problem is that it had gravity fed carburetors, go into a parbabolic dive and the carburetor failed to work.... kinda like the wieghtless simulation flown by NASA 747 to train astronauts... the plane falls faster than the fuel so the fuel cannot get into the cyclinder...

I think tho that you could fly upside down because of a 2nd inverted carburetor that fed the engine when upside down, the engine would die, pick-up, die and pick-up again as you performed a roll.

Download Warbirds simulation.... have a fly in their Spit I and Spit V and see the difference.

 

[Von Falke]

Thanks for your answers!
I just wonder how many pilots that got lost becasue of this problem and how serious it was considered to be.
i can imagane that in a dogfight, when u fly about, it would be preferable with a engine that dont malfunction..
otherwise, the Merlin was a very reliable engine wasnt it?

 

[mad_max]

Once the bugs were worked out just as most other engines it was quite reliable.

Most fighters were only approved to fly inverted for a scant 1-2 mins as they would be
starved of oil. Besides they were quite hard to fly inverted for any length of time because
of the airfoil shapes.

FWIW

 

[Morai_Milo]

There was 2 stages to the Merlin cutting out. The first was the lean mixture when the float bowl ran out of fuel due to neg Gs. The second was the rich mixture cut-out when the a/c went inverted and the float fell to the top of the bowl allowing an unrestricted flow of fuel to the cylinders.

Do a Google search for 'Miss Tilley's orfice' for a more detailed description and fix.

 

[fire-ball]

yea the spitfire had rounded wings unlike the me109 so it made easier flying when in the air which helped make up for engine and machine guns because the me109 used fuel injection and connons not machine guns

 

[bomber]

yea the spitfire had rounded wings unlike the me109 so it made easier flying when in the air which helped make up for engine and machine guns because the me109 used fuel injection and connons not machine guns

Oval shape of the wings reduce interference drag that occur at sharp corners...

I can assure you that the supercharged Merlin engines were on a par if not better than the German fuel injected versions...

Having spoken with the designers of the Merlins, they've told me they were asked to look into producing a fuel injected Merlin but after consideration to the aircraft as a whole, not just to the engine it was determined that there'd be no gain from converting.

Simon

 

[fire-ball]

also the rounded wings on the spitfire allowed the pilots to realize the how hard the pilots could take the plane unlike the me109 which pilots never new how hard to fly the sucker

 

[lesofprimus]

WTF are u talking about???

 

[mkloby]

also the rounded wings on the spitfire allowed the pilots to realize the how hard the pilots could take the plane unlike the me109 which pilots never new how hard to fly the sucker

Yeah...

 

[trackend]

Beats me Les

 

[lesofprimus]

Dumb ass kids who cant speak English.... Bad combo...

 

[Matt308]

 

[Sgt. Pappy]

lol c'mon kids, let's be nice now xD

anywho, Spitfire Mk.I's and II's had carburettors and no fuel injection. The engines were Merlin III's and Merlin XII's respectively. This wasn't actually a mistake. It was believed to produce a little more power than a fuel injected engine such as the Daimler Benz engines of the Me/Bf 109's.

Going inverted would cause the engine to starve of fuel and if the negative G position was held too long, the pilot would have one nasty spill all over his windshield. A temporary fitting was applied in 1941 to Spitfire Mk.V's and it was known as 'Miss Schilling's Orfice' which esentially modified the carburettor to allow fuel to stay in the engine even during - G maneuvers. Later Merlins were fuel injected.

 

[ridato]

First Merlin engine Models use carburettors, late models use indirect fuel injection (german DB use direct fuel injction).
Regarding to the shape of wings, Spitfire has elliptic wing. This type of wings offer the minimum induced drag. This type of wing was used frequently a this time, see He 70, He111, Aichi D3A, etc..
The Spitfire use elliptic wing for other reasons, the designer want to keep the thickness to a minimum (Spitfire has a thickness of about 11%, while others aircrafts the same time use 15%). The reason for this thickness was high speed aerodynamic. The only way to accomodate 8 machine guns and keep the thickness without bulges was the elliptical wing planform. The big problem of this wing was time to manufacture, it require a lot of more manhours and cost more money.

 

[Sgt. Pappy]

the wing also would shudder at the tips near a stall. this would give the pilot early warning to correct his maneuvering.

 

[Smokey]

the wing also would shudder at the tips near a stall. this would give the pilot early warning to correct his maneuvering.

That's what fire ball was referring to

also the rounded wings on the spitfire allowed the pilots to realize the how hard the pilots could take the plane unlike the me109 which pilots never new how hard to fly the sucker

 

[ridato]

well, stall should start at wing root in a good designed aircraft to provide a good stall warning with aileron control, if stall start at wing tip you loose the aileron and the aircraft could enter to a spin. Usually wings have a washout of about -2 or -3 degrees, so the angle of attack in wingtip is lower than in the wing root. A big problem in aerodynamic elliptic wings is that lift is constant spanwise, so stall start all the wing, and if a washout is provided in the design of the wing, the wing is not aerodynamically elliptic.

 

[mike nixon]

It had a float carb. reduce the G force, and the fuel rises. the mixture gets rich and the engine quits making noise. increase the G and the effect is not as bad as the change to lean was not as pronounced. the fix was to change the gasket over the fuel chamber to limit the fuel level. the real fix was to change the engine over to an american stromberg pressure injection unit.
Mike Nixon