Spitfire engine failure in dive?

[Major]

I heard some where that the Spitfires engine would cut off in a dive. What varients did this apply too? I think it only happend to the mkI and was corrected from mkII on. Correct me if im wrong.

thanks

[ccheese]

One of the Brits may be able to help you, Major....

But, I'll welcome you to the forum....

Charles

[Major]

Thanks

[timshatz]

It was the engine on the early marks of Spitfires. Had a standard, gravity fed carb. Would cut out in negative g. Brits fixed it with a "floating" carb. Seemed to do the trick.

Germans 109s used a fuel pump. My understanding is it was in the gas tank itself. Pretty smart engineering, if accurate.

[Major]

So in what variant was this problem corrected? Did it only apply to the mkI?

thanks for the answer

[claidemore]

Not sure that "engine failure" would be the correct term to describe that phenomenon, usually it resulted in the engine sputtering and coughing as a result of reduced fuel flow, rather than complete fuel starvation. Pilot had to hold negative G for an uncomfortable length of time to cut the engine out completely and it would roar back to life as soon as they returned to positive G flight.

Starting during the production of the Mk V they used a modified carburator, designed by a female engineer, that was referred to as "Miss Shillings orifice". This partly fixed the problem.
The Bendix-Stromberg carburater in the Mk IX was the final solution and eliminated the problem completely.

The DB engines on the Messerschmitts were fuel injected.

[Major]

Thanks for the reply.

I just read something saying that they started using the carburetors on the mkV spitfires. Is this true or did they start using them later on the mk IX?

[claidemore]

Originally Posted by Major

Thanks for the reply.

I just read something saying that they started using the carburetors on the mkV spitfires. Is this true or did they start using them later on the mk IX?

They used the modified carbs (shillings orifice) on the Mk V's, the Bendix-Stromberg carbs came on the Mk IXs. I believe the B-S carbs (lol) were retro-fitted on MkVs, not 100% certain on that.

Claidemore

[Major]

K i just read this:
The first improvement was the shilling's orifice, after that rolls royce made an improved carburetor that could take sustained negative G's (they were put into all rolls royce engines from merlin 45 on), than the final version was the bendix, which were fitted on merlin 61's and above.

correct me if im wrong

[Flyboy2]

Its my understanding that to counteract this problem the Spitfire pilots would split-S a dive. They would roll upside down and then dive to maintain positive G's in the dive so the engine wouldn't sputter. This is opposed to the Bf-109 which could just go right into a dive because of thier injector system.

[kool kitty89]

The Bendix-Stromberg carburater in the Mk IX was the final solution and eliminated the problem completely.

I thibk this was a "pressure carburetor" like those used by the V-1710. This is basicly the same type of mechanism as "single point fuel injection" (throttle body ingection in GM terminology) which uses a pressure pump to inject fuel through a spray nozzel into the intake manifold or throttle body.

This also explains why the V-1710 (and other US engines using these carbs, including the pre war R-1820 and R-1830, never suffered from -G or inverted flight cut-out problems)

[kool kitty89]

Originally Posted by Flyboy2

Its my understanding that to counteract this problem the Spitfire pilots would split-S a dive. They would roll upside down and then dive to maintain positive G's in the dive so the engine wouldn't sputter. This is opposed to the Bf-109 which could just go right into a dive because of thier injector system.

As long as tou kept pulling +G's you'd be fine.


One thing I've wondered about though is what about the DH. Mossie and Westland Whirlwind. With the Mossie using early Merlins and the Whirlwind using Perigrines (which should have similar carbs), wouldn't simply rolling the a/c cause an engine (the one rolling downward experiencing -G's) to sputter, or if it was a hard roll (combat maneuvering) cause the engine to cut out completely?

That would pose a serious problem, and one that contemporary German and US designs didn't have to face with all combat engines using either pressure carbs or fuel injection. (though it was carburetor fed, I think the DB 600 used a pressure carb too, which was being replaced with the direct injected 601 aniway and the Jumo 210G, 211, and BMW 801 were all direct injected as well)

[slaterat]

The neg g problems on spit 1 and Hurri Is were two fold. Initially at the onset of neg g the fuel and float would splash to the top of the float bowl, closing the needle valve and starving the engine of fuel. If the neg Gs were sustained the heavier fuel would displace the float downwards opening the needle valve flooding the engine and could potentially lead to engine hydrolock.

The first sloution was the famous shilling orifice. introduced after the BoB, that restricted fuel flow and prevented the second problem of flooding the engine and hydro lock.

The next improvement was a baffle in the float bowl that helped prevent the fuel and float from surging upward under limited neg gs. this allowed short neg g manouevres. This was used on spit v s Hurri IIs and merlin 61 Spit 9s afaik.

Latter merlins had the stromberg injector carbs(throttle body injection) allowing sustained neg g manouevres.

Slaterat

[Major]

Hmm I wonder how long the shillings orifice allowed the spitfire to peform neg G stuff, ive searched a little and it seems that no one knows the exact amount of seconds the spitfire could peform neg G stuff without the engine sputtering.

Also, did the Rolls royce Griffon engines have this problem also?

[claidemore]

Major;

From a Rolls Royce Griffon book, Griffon engines had the Bendix carb.

I believe you can view that document at the link below, as well as a host of other Spitfire related info. I may have downloaded it from there too.

You should also check out the Techincal Section on these forums.

Spitfire Performance Testing