What am I doing wrong? 2-stage prop spitfires.

[Space Communist]

Ok so I have put a number of hours into the game and I have gotten I think pretty proficient at flying the Hurricanes and Spitfires with variable pitch props (CEM on.) I am able to fly a Mark II Spit level at about 300 mph IAS, which more or less agrees with the real top speed as I understand it.

Now the Ia with its 2 stage prop should actually have a pretty similar top speed in the coarse pitch setting I would think, but I struggle to get it to 250 mph, normally no more than 240!

now I know some people have been claiming some of the flight characteristics are a little off but is there really a 60 mph difference between these 2 planes? If not what on Earth am I missing?

Edit: Looking up stats it looks like the 2 aircraft should have nearly identical top speeds, though the speeds I have found are at 17000 ft, and I am testing at about 4000 ft. Can the prop make that big a difference between low and high altitude? i.e., would the difference disappear at higher altitude?

[Vengeanze]

Ok so I have put a number of hours into the game and I have gotten I think pretty proficient at flying the Hurricanes and Spitfires with variable pitch props (CEM on.) I am able to fly a Mark II Spit level at about 300 mph IAS, which more or less agrees with the real top speed as I understand it.

Now the Ia with its 2 stage prop should actually have a pretty similar top speed in the course pitch setting I would think, but I struggle to get it to 250 mph, normally no more than 240!

now I know some people have been claiming some of the flight characteristics are a little off but is there really a 60 mph difference between these 2 planes? If not what on Earth am I missing?
I get the same top speed as you (240ish) in the Ia and Hurricane.

[ATAG_Doc]

I do not relish flying the 2 stage prop pitch at all.

[Ze-Jamz]

Ok so I have put a number of hours into the game and I have gotten I think pretty proficient at flying the Hurricanes and Spitfires with variable pitch props (CEM on.) I am able to fly a Mark II Spit level at about 300 mph IAS, which more or less agrees with the real top speed as I understand it.

Now the Ia with its 2 stage prop should actually have a pretty similar top speed in the course pitch setting I would think, but I struggle to get it to 250 mph, normally no more than 240!

now I know some people have been claiming some of the flight characteristics are a little off but is there really a 60 mph difference between these 2 planes? If not what on Earth am I missing?

Edit: Looking up stats it looks like the 2 aircraft should have nearly identical top speeds, though the speeds I have found are at 17000 ft, and I am testing at about 4000 ft. Can the prop make that big a difference between low and high altitude? i.e., would the difference disappear at higher altitude?

Yes there is that much difference between the 1a and II in game... the 1a FM is porked

[Buzpilot]

Could it be that MkIa two stage prop in reality use different coarse than ingame, like gear 1 and 2 instead of 1 and 4th gear?

Edit; It's coarse, not course like many in here use http://dictionary.reference.com/browse/coarse

[Space Communist]

Could it be that MkIa two stage prop in reality use different coarse than ingame, like gear 1 and 2 instead of 1 and 4th gear?

Edit; It's coarse, not course like many in here use http://dictionary.reference.com/browse/coarse

Ah yes you are right of course. I am just so much more used to typing that rather than coarse.

I was actually kind of thinking along those lines (the pitch of the coarse setting being wrong) since the top speed of the MkII seems to be at around 2700 rpm, and the coarse setting of the Ia drops it down to less than 2200 in level flight. When I get a chance I will drop the rpm of the Mk II down to 2200 at full throttle and see what happens.

[Blackdog_kt]

The two-stage prop operation is essentially like exchanging one fixed pitch prop for another in mid flight.

What is the most tell-tale characteristic of such props? The fact that RPM is not constant for the exact same pitch value.

If you go faster the RPM will go up, if you go slower it will go down and all this while you're not even touching the pitch controls.

Why am i mentioning all this? Because even though setting the pitch to coarse might drop your RPM too much, you can still make it reach the 2700 RPM sweet spot by speeding up a bit ;)

Give it a bit of a shallow dive and trim level as you pick up speed and it wants to pull the nose up, you'll see she picks up speed and keeps it in a much better way.
Hope it helps ;)

[justme262]

I just did a test in Spit Ia and got IAS of 255mph @ 17300ft @ 2750rpm on coarse pitch setting.
I put that into a TAS calculator and got 342mph.
I was running level till the speed stabilized after a shallow dive at about 270mph IAS. But it was holding pretty steady for 20 seconds or so.

The course prop setting gives much higher RPM at altitude where the air is thinner. I have come to like de Havilland two speed props. I think they actually historically had a better top speed than the Rotol prop fitted versions. But the Rotol had better climb and acceleration. You just gotta be at high alt to get the most out of em...


http://img857.imageshack.us/img857/1104/iasq.jpg

http://www.csgnetwork.com/tasinfocalc.html

[robtek]

if that sideslip was there all the time you could have gon even faster by correcting it. :-D

[justme262]

I'm sure I could have gone faster...
I was trying to fly as even as I could with just rudder and elevator trim. with out aileron trim I couldn't get it dead straight.

I had half a tank of fuel and full guns... radiator half open... and didn't even touch the boost cut out.

With 5% fuel, empty guns, fully closed radiator, and throttle pushed through the gate I think it might do 355mph TAS.

http://www.spitfireperformance.com/spitfire-I.html

[Ze-Jamz]

What high alt are you talking about? That Aicraft is horrible to fly at high alt, handles like a pig and is very easy to overcook the engine

[justme262]

The original poster said he tested at 4000ft. The spit mkI had it's best speed at about 17 or 18000ft. That's much higher altitude.
The spitfire flys beautifully at any altitude. At least when I fly it...
maybe you just need a little practice ;)

Someone suggested the mkI and mkIa ingame are running on 87octane at 6.25lb of boost and the mkIIa is running on 100octane at 12lbs of boost. Supposedly the mkIIa's running 12lb of boost still had an old boost gauge that only went up to 8lbs though. I vaguely remember checking this ingame.

Anyway that would still make our mkI spits more like Battle of France performance not Battle of Britain performance.
The 3d model on the mkI is a DH prop and the 3d model on the mkIa is a Rotol prop. If you look at them from outside. Same prop models as on the hurricanes.