Pyro; about 109...

[Sorrow[S=A]]

Because, with a mechanical fuel injector, not using a computer to measure air pressure, etc etc all engines run slightly rich (being a whole lot safer than lean!) Technology only went so far back then. I am not so sure about those being the only to controls..  I am POSITIVE there was a mixture control somewhere on that plane. Otherwise there would be no adjustments at all for high altitude flying.

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If your in range, so is the enemy.

[Sorrow[S=A]]

Actually after a bit of research it appears there WASN'T one...  how odd. I am curious now how they did it. Somehow on the supercharger they had some way of adjusting boost to compensate for lower oxygen levels at alt? or did they actually figure a way to measure fuel mixture in the injection pump back in '39?

How odd. 2 other things that came to mind are that yes, all fighters ran rich in combat. It compensated for the massive drops and rises in air pressure at alt in combat. Wasn't a big deal, those motors got overhauled regularly anyway.
 The other was the memory that with direct injection you pretty much HAVE to have a constant air pressure. hence with cars who was going to bother adding it when you had to have a super or turbo charger? It probably wasn't a serious idea until nowadays that we see turbo's and supers on 4cylinder cars becoming more common.

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If your in range, so is the enemy.

[chisel]

Sorrow,

 They invented a small, thin, flat piece of rubber called a diaphram    
So what if they ran a little rich? ALL of them did, carburated or injected. Helps keep it cool and prevents detonation.

Daimler used a hydraulic slip clutch on the blower drive controlled by atmosheric pressure. pressure drops, clutch tightens up and blower spins faster.

Just a guess but I think the big thing with neg G on carbs is the float needle popping open or staying shut. flooding or starving the engine.


Juzz,
 When I first saw "Direct" injection on these engines I was in disbelief. Not because it was injected but because spraying the gasoline directly into the combustion chamber still isnt done on a car to my knowlege. Could be wrong, I'm a diesel guy.    

With regards to use on cars. Porsche used Bosche mech. fuel injection in the 60's 70's
Did the corvair have fuel injection? Was basically a continental flat six wasnt it?

I asked this question before and there were 2 cars that used pressure carbs. They are cheaper than fuel injection and infinately better than float carbs why werent they used.

Antilock brakes have been around since the 40's on planes why werent they used on cars?

Betcha it has more to do with cost than anything. Computer just made these items cheap enough and idiot proof for mass consumtion.




[This message has been edited by chisel (edited 12-19-1999).]

[wells]

The '57 Vette was fuel injected.

[Sorrow[S=A]]

I agree Chisel, cost more than anything. BTW the 289 GM motor had mechanical fuel injection, so did mid 30's buicks and several other cars. Complexity was their downfall, too hard to service.

  I think the problem with carbs was to do with fuel being unable to draw properly when the negative pressure exceeded manifold vacuum. Later Packard Merlins utilised superchargers and pressurized fuel systems to overcome this. However to the best of my knowledge most spitfire IX's should still have engine failure under heavy negative G. Not as bad as mark I or mark V but it should still happen.

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If your in range, so is the enemy.

[janneh]

Thanks guys for details  

Was that old bosch fuel injection named something like "Kulgerfischer" ?

Chisel, if I recall it right, I've read somewhere about direct injection(gas) car, a japanese car and it's already in serial production.

BTW, was there any water injection used on these plane engines ?

Nice site juzz  

Sorrow, that negative G effects on spits (all spits), should be modelled in AH.
Otherwise it's allied conspirancy  

[Hristo]

Diverting a bit now...

So Spits should have problems with negative Gs, even in their later versions ? How about P 51 ?

BTW, both of these planes can readily push more negative Gs than 109. Not as drastic difference as before, but still too great. 109 should be better in that regard, both elevator and engine wise, shouldn't it ?

AH 0.42 109 has to be trimmed down to do it, and it still won't do it as fast as Spit or P 51, at any speed. There is also nose bounce effect, so in 109 it is usually -2g, 0g, -1g sequence.

[Sorrow[S=A]]

P51 has no problems Hristo, they used Packard Merlins. Packard solved all the problems of high altitude. Their intake system and carbs were very different than the ones RR was using. It was Packard's sharing of this knowledge that allowed the late Spit IX finally be totally free of any high G problems. The early and mid ones were results of RR trying to fix the problems themselves and were only partially successfull. Actually it's relative, the fixes began back with the Mark V. But with every fix they found more problems. The IX shouldn't have too many stall conditions, only under 5-7+ -G would it probably start to have issues. This is probably why it isn't even modelled in AH. We fly a late model IX, the odds of it being in a high -G situation proabably weren't worth making it stall there.

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If your in range, so is the enemy.

[Flathat]

So are we saying the down elevator issue on 109s is still an issue? My last two online sorties were in 109s (got bored dying in ponies and hawgs and decided to die in something else  ), and I noticed that it seemed I just couldn't get the nose down quickly, even at sub-compression speeds.

But I'm about as far from an experten as you can get, and would be happy to hear from those who know more than I do....

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Flathat
'Black Dahlia'
No10 RNAS "The Black Flight"
Angel on your wing, devil on your tail

[Hristo]

Flathat, this is only my subjective remark. It would be nice to have opinion of real 109 expert, -ik-.

109 has somewhat slow trim response and it requires quite a bit of trimming during flight, especially compared to 190 (requires almost no elevator trim). This is ok, IMHO. But still, its down elevator is worse than the one in Spit or P 51D, even if trimmed nose heavy.

From what I have heard, and from WB model as well, it should be just the opposite. Hartmann's escape is now easier in Spits than in 109.

And nose bounce makes things even worse. Here's usual case at moderate speed, trimmed for level flight. You push elevator and achieve some -2g (far more achieveable in Spit or P 51). Then the down movement stops (nose bounce) and you can read 0g. After that it is some -1.5g sustained. Even if you started trimming the elevator down at the beggining of the maneuver, the results are still not all that good.

[Flathat]

Yep--I wasn't reading the gauges at the time but otherwise that describes my experience under conditions closely resembling what you described. Thanks, Hristo.

(Changing the subject a little) You know, the worst thing about having limited flying time is not so much that I don't become a feared experten, but that I don't get enough time in each of the available rides to determine whether or not it's for me. I suspect that my particular brand of dweebishness is ultimately going to make me a HawgDweeb(tm), but who knows? I might really learn to love the 109, La-5 or Veltro, particularly if the latter had fuel enough to do more than take off and land. I've flown them all along with the Pony (a lot) and the Spit (once). That's what stops me joining a squad, too--the thought that I Might Be Missing Something.  

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Flathat
'Black Dahlia'
No10 RNAS "The Black Flight"
Angel on your wing, devil on your tail

[Duckwing6]

a li'll out of subject ... but HawgDeweeb?? naawww Dweebfire -> THAT's the ultimate Dweebplane   -> and yes please give them negative G limitations..