Please Fix the Hurri 1 and Spit 1

[Seagoon]

Dear Hitech,

By now everyone knows that high negative G meaneuvers caused the float in early Merlin engines to flip up and briefly cut off the engine, and that as a result Luftwaffe pilots during the BoB would often go into a steep dive to shake off British fighters.

However, as it is currently modeled, the engine in Spit and Hurri 1s cuts off when any negative Gs are applied, no matter how gentle. I push the stick forward, the engine cuts off. At present, maneuvers that wouldn't make the dust on the cockpit floor rise cause the engine to cut out. Maneuvers that wouldn't have starved the inline engines on WW1 fighters currently kill our Spit and Hurri 1 engines.

Can you please alter the modeling to reflect the fact that it is high negative Gs (i.e. a STEEP dive or severe inside turn, etc.) and not just any negative G maneuvers that cause the engine to shut off?

Thanks,

SEAGOON

[Kweassa]

The engine cuts off when the total applied G force on the plane is lesser than 0 - hence, "negative G".

 If you push on the stick, but the total G load is still higher than 0, then the engine still functions.

[Karnak]

The one change that should be made is that WEP should not be disengaged when the engine cuts out and restarts.

If you were on WEP before the cutout you should be on WEP after the engine restarts.

[Xjazz]

Hi Seagoon,

Hurricane Mk1 is my main ride in h2h side.  The neg-G engine cut off is not the problem once you get use to it.  

In some neg-G situations you will get totally engine shutoff and you just restart again with E-key.

[Seagoon]

Guys,

Thanks for the feedback, I am familiar with the physics of the engine cut-off and am a student of the history of the development of the Spitfire, although not the Hurricane. I had an opportunity to talk about this with a Spit expert at Duxford on a trip back to the homeland (although at the time I was disappointed that the earliest Spit they had in the collection was a 5 - don't know if that has changed since) a few years ago who had in turn spoken with Jeffrey Quill about this and other problems. Incidentally, he noted that Quill had told him he regarded Aileron and Coolant problems to be the big bugbears in combat with the early mark Spits and not engine cut out.

The fact is that the engine did not cut out with mild negative G maneuvers any more than human beings "black out" with mild positive g maneuvers or "red out" with mild negative g maneuvers and AH2 obviously attempts to model the actual scale. The situation in the Carburetor of the Merlin is similar. The engine would only cut out when the neg g load (or unload if you will) reached a point that the float in the carburetor was all the way up and closed off the needle valve flow to the engine. This occurred when the pilot suddenly nosed the aircraft down into a really steep dive. At present the engine cuts out when you nose down slightly for landing (producing a brief low negative g), a situation that would have caused a LOT of crashes in reality. I never bothered to ask what the negative G point was when the engine cut off (-2, -3, -4 etc.) but it certainly wasn't -1 G and under as it is in the game.

If you want to enter into a discussion of this and have solid information that the slightest amount of negative Gs (-0.1 to -1) produced the cut off, I'll be glad to stand or rather sit corrected, but as this would have made the aircraft totally unsuitable for use in combat I rather doubt it at present.

Thanks,

SEAGOON

[Krusty]

The negative G cutoff is modeled well. I have nosed down and NOT lost engine. You can't go jamming the stick around. Ease it down. Or if you have to, invert and pull up (doesn't take much longer to do).

Also, what I have noticed is this:

There is a time limit for the gas-starved engine. If your negative G period is short, the engine will restart. If you pass whatever that short time limit is, the engine must be restarted. I don't know if this is a BUG or if it's intentional. If intentional, it's highly unrealistic, as the engines had to be started on the ground by ground crew, if I recall. Didn't they need starter boxes? Especially for hurcs?

Anyways, I'd rather have the engine "stay on" even when cut off, as there should be no way to restart an engine in flight with no power. ... At least I'd think.

[Xjazz]

I really dont know if Hurricane Mk1 & spitfire Mk1 engine & carburators are modelled accurate but

"unsuitable for use in combat "

is  pure BS

IMHO
Current neg-G model just require some practice/skill to manage this quirk during  the combat.

[J_A_B]

Remember that pilots tended to not use negative-gee maneuvers that much to begin with because all the dirt and crap on the cockpit floor flies up in your face.   Mostly they wouldn't go past the 0-g point and if they needed to dive quickly, they'd wing over with the ailerons first and pull positive g's into the dive.


J_A_B

[Seagoon]

Xjazz et al,

I have flown the Hurri 1 and the Spit 1 in the current AH configuration and gotten kills and assists with both. Please understand this is not an "I don't like the way this aircraft doesn't work for me in AH2" whine. I know full well the cutoff can be managed in online combat. Yes, even a brief pilot redout every time you did any level of negative Gs could be managed, but most of us would agree that it wasn't quite realistic.

What I am pointing out is that the current Carb. configuration is unlike the historical one and that fighter command would never have taken delivery of a fighter aircraft with an engine that cut-off every time a mild amount of negative G was endured. As I mentioned, the problems with this in landing alone (and our landings are on rails compared to reality) given what can happen when an engine suddenly cuts out with a cross wind blowing or on a very hot day, etc. would have made the aircraft a widowmaker under operational conditions.

At present, while I am eager to do so, I have yet to see any historical evidence that the engine cut out every time minor negative G loads were endured. I am not arguing that the engine shouldn't cut out under high negative Gs - history tells us the real one did. What I am arguing is that the current level is ahistorical.

Guys, think about it, the very fact that our Merlin engine cuts out without us seeing ANY pilot red-out should tell you that the effect is overmodeled.

- SEAGOON

[Krusty]

redouts take effect at the same level as blackouts... that means about +4 to +5 and -4 to -5 Gs... so if the carb cuts out at -1 there's plenty of room between the cutout and the red out.

I have RARELY had redouts in the spit1/hurc1. Nor have I EVER had it cut out on landing because I nose down. I'm not the gentlest stick, either. Maybe it's your setup, or something? Because what you are describing has never happened to me, and I actually like flying them.

[Xjazz]

TimRas provide this link . Thanks

http://www.spitfiresociety.demon.co.uk/engines.htm

"Carburettor design

One of the great problems as discerned by pilots was the tendency for the carburetted engine to cut out under negative 'g'. Luftwaffe pilots learned to escape by simply pushing the nose of their aircraft down into a dive, as their fuel- injected engines did not cut out under these circumstances. Many authors have criticised this aspect of the Merlin design. In reality, like most engineering, it resulted from a design compromise- the drop in temperature developed in a carburetor results in an increase in the density of the fuel-air mixture when compared to that of a fuel injection system. As a consequence the Merlin produced a higher specific power output (horse power per pound) that the equivalent German engine. It was felt that this gave a higher power to weight ratio for the fighter and (rightly or wrongly) that this outweighed the disadvantages. By 1941 Miss Tilly Shilling in Farnborough had developed a partial cure for the problem. A diaphragm across the float chambers with a calibrated hole (the infamous "Miss Shilling's orifice"!) allowed negative 'g' manouvres, and was fitted as standard from March 1941. Sustained zero 'g' manouvres were not sorted out until somewhat later. In 1942 an anti-g version of the SU carburetor was fitted to single and two-stage Merlins. 1943 saw the introduction of the Bendix-Stromburg carburetor which injected fuel at 5psi through a nozzle direct into the supercharger and was fitted to the Merlins 66, 70, 76, 77, and 85. The final development was the SU injection carburetor which injected fuel into the supercharger using a fuel pump driven as a fuction of crankshaft speed and engine pressures, which was fitted to the 100 series Merlins. "

[Kweassa]

Not sure just how much "tolerance to -G" or "chance to resist cut out" you're thinking of Seagoon, but in the Merlin engine demonstration I've seen(secon-hand source, ofcourse) the moment the engine hit -G it started to cut out. The demonstration was simple - they turned the engine upside down, and it immediately began to wheeze and cut out.