Spitfire RPM's

[Blackdog_kt]

Originally Posted by *Buzzsaw*

Salute

Two position props were not in general use during the BoB as I have proven in a previous post.

http://forum.1cpublishing.eu/showthread.php?t=21066

All Spitfires I's were converted to Constant speed props starting in late June of 1940, conversions were a matter of a few weeks.

The only relevance for two position props is for scenarios set before the BoB, ie. Dunkirk, interceptions of early recon flights over Britain, etc.

That is true, but since we do have a constant speed prop Spit that is mostly similar in all other respects i don't think it's such a big issue. I mean, we have a correctly performing one for the time period in question, so that relegates the whole issue to a naming convention for the aircraft in the sim.

The easiest solution would be to add the extra variations (it should be easy since it would just need to take the prop from the Mk.II and bolt it on to the Mk.I 3d model) and then re-label the Spits according to the way it's done for the Hurricane. This way, we would have "Spit Mk.I, two-stage prop" and "Spit Mk.I, constant speed prop" and everything would be correctly labeled and accurate

At present, i find that applying fixes that can have an effect across the board is of a higher priority, like for example fixing the auto-mixture algorithms that would affect almost all of the fighters in the game. I'm not saying the Spit shouldn't get corrected, i'm just saying that it's the aircraft with the most variants and one of them performs close enough to real life data, so maybe it would be more prudent to focus on improving flyables that are further off the mark at this early stage.


As for the 100-octane fuel issue, it should definitely be fixed. However, i doubt it would be of much use in full switch flying for a very simple reason: it might prevent detonation and let us run the engine at higher ratings, but overheat is still there and it's the main limiting factor. The only real use would be in absolute emergencies (read: checking six and seeing a bunch of cannon muzzles light up with tracers streaming my way).

For normal flying and even during combat, i prefer to use a more conservative value with short bursts of full throttle with my radiator almost closed, instead of firewalling it for the whole dogfight and having to run the rads full open. Overheat forces radiator use and the resulting drag defeats the whole purpose of the added power. If i can run a cool engine with a low drag profile i'm not only maximizing my fuel usage, i'm also maximizing the effectiveness of my brief, full throttle bursts: the engine is cool enough that it can take max boost with the rads at about 30% for half a minute or so, which is usually all it takes to decide the outcome of a zoom-climb chase or an evasive attempt.

Long story short, even if we get +12lbs engines i don't expect to be able to use it for any length of time that would provide more than a token advantage at very extraordinary situations, it was after all labeled as an emergency power setting and not a continuous one.

[Viper2000]

The Dh 20º prop is not the same as the Rotol 35º prop by any stretch of the imagination, even after the former has been converted to CS operation.

The Merlin XII has a higher supercharger gear ratio than the Merlin III which considerably increases the FTH for +12 psi operation, thereby making better use of 100 octane fuel, as well as improving altitude performance in general. However, performance below about 10,000 feet is consequently worse than that of the Merlin III due to the increased supercharger power consumption.

Since most combat during the Battle of Britain took place at about 18000' (which was the altitude the German bombers chose to fly at), the main effect of 100 octane fuel was to increase the RAF's climb performance, allowing them to make effective interceptions with shorter warning time, since even the Merlin XII couldn't deliver +12 psi boost above about 10500' static (so say roughly 12000' with 350 mph of intake ram).

Obviously this was important, but it affects the early part of the chess game, rather than the end game. Unfortunately, most people tend to see aerial combat in terms of the end game; but my online experience has shown me that in fact once the hard manoeuvring has started, quite often the outcome is already decided, the winner having initiated combat from a position of advantage.