Spitfire Question

[Skorteus]

I was telling an ex Navy pilot and aircraft historian friend of mine about IL2-Sturmovik BOP game ...and he asked me to check something out. Since it will be hours before I can play again, I thought I'd ask the question here.

According to him, the Spitfire had a known issue with the float in the carburetor.... he said if it was flown inverted for too long that the engine would die. Can anyone confirm this as a fact...and does anyone know if it happens in game?

[MorgothNL]

yes the merlin engine did have this problem ... but in game?? lets check it out... brb in 10
I know the mk XVI has the griffon engine... and I dont know if it had the same problem... so I will take another spit

[MorgothNL]

nop....it keeps on flying (tried with the spit mk II because that one for sure has the earlier merlin engine)

[P-51]

The game doesn't have it, this is because they have accurately modeled the Mk 2 spitfire and not stuck the Mk1 in with a pair of cannons
By the time of the Mk 2 they had identified this problem as the fuel was forced through by gravity not a pump. I believe tall they had to do was place a piece of mettle inside the eenginethat swivels and was weighted in a way that in negative 'G' it would swing down and stop fuel flowing backwards. Although i may be wrong on the solution bit do correct me if i'm wrong!

[MorgothNL]

did they fix it in the mk II allready? I thought all merlins till at least the mark IV had the problem (IV is the first one with the griffon engine right ? )

[Skorteus]

Somehow I knew this would spawn an interesting conversation....you guys are fascinating to listen to.

[MorgothNL]

I did some research and found that indeed did the pilots could help the engine by inserting a piece of metal... but that didnt really fix it. because for this 'fix' to work..they HAD to dive at full power, wich was not always what they wanted. It was only in the last 100 series merlin that they put in a direct injection fuel pump .

The 60-85 variants also had a fuel pump...but this one did not have enough power. The 100 variant was using the crackshaft speed.

Now...I do not know wich spit had exactly wich variant of merlin .. but I think the mk2 was to early to benefit from the fuel pump variants


EDIT: this is what I found on wiki
the Merlin's lack of direct fuel injection meant that both Spitfires and Hurricanes were unable to pitch nose down into a steep dive. The contemporary Bf-109E, which had direct fuel injection, could "bunt" into a high-power dive to escape attack, leaving the pursuing aircraft behind because its fuel had been forced out of the carburettor's float chamber by the effects of negative g-force (g). RAF fighter pilots soon learned to "half-roll" their aircraft before diving to pursue their opponents.[25] "Miss Shilling's orifice",[nb 5] a holed diaphragm fitted across the float chambers, went some way towards curing the fuel starvation in a dive; however, at less than maximum power a "fuel rich" mixture still resulted. Another improvement was made by moving the fuel outlet from the bottom of the S.U. carburettor to exactly halfway up the side, which allowed the fuel to flow equally well under negative or positive g.[26]

Further improvements were introduced throughout the Merlin range: 1943 saw the introduction of a Bendix-Stromberg pressure carburettor that injected fuel at 5 pounds per square inch (0.34 bar) through a nozzle directly into the supercharger, and was fitted to Merlin 66, 70, 76, 77 and 85 variants. The final development, which was fitted to the 100-series Merlins, was an S.U. injection carburettor that injected fuel into the supercharger using a fuel pump driven as a function of crankshaft speed and engine pressures.[27]


still ... I dont know what aplies to wich spit

[Wissam24]

I've read that the F4U used to stall on the starboard wing before the port one at low speeds

[MorgothNL]

Originally Posted by Wissam24

I've read that the F4U used to stall on the starboard wing before the port one at low speeds

Yeah...I heard the same thing... but I could never figure out why this would happen . I can imagine it to happen at a go-around due to sudden torque effects... but I heard that the problem was mostly while landing on the carriers.
I understand that landing brings you close to stall speed...but why would one wing have this before the other one? prob because of the ugly looking wings

[Soviet Ace]

Originally Posted by MorgothNL

did they fix it in the mk II allready? I thought all merlins till at least the mark IV had the problem (IV is the first one with the griffon engine right ? )

That would be the MkXIV with the Griffon.

OH DAVID!!! WHERE ARE YOU!!?