wep on RAF planes awol???? boost levels??? no 100 octane fuel:(

[Moggy]

If I were doing 240 MPH IAS at 18,000 ft, I'd be pretty happy as I'd be tootling along at 330 MPH TAS. That's according to Bombsight Table 2.

P.S. Flying Pencil, they're both in France (Lille is very close to the Belgian border) and yes...I had to check on google maps!

[Osprey]

Given the 1C have handed out Spitfire pilot notes books with the collectors edition I imagine that they will have to match whatever settings are in the book.

Boost drops off with altitude so you have to apply more power as you ascend, did you do that??

[Biggs]

Originally Posted by Moggy

If I were doing 240 MPH IAS at 18,000 ft, I'd be pretty happy as I'd be tootling along at 330 MPH TAS. That's according to Bombsight Table 2.

my mistake i was reading the CoD manual wrong... the manual says 225IAS @ 18k is 296TAS... After trying it again Im just hitting 220IAS which would make it more like 290-ish TAS

either way its not what the aircraft should be doing at that alt!.. at spit mkI with a MerlinIII engine with a 2-pitch prop should be doing at least 350 TAS at 18K

this is way off.

[Biggs]

Now the mkIIa seems spot on...

@18k on full WEP boost (only managed 4lbs at that alt) with the prop at about 2850 revs I was able to hit the 280IAS mark (354TAS) which is what it should be!

the mkI's seem to be off...I'm not sure about their climb rates being off yet but the top speeds are DEFINITELY off.

In summation: mkIa's prop is bugged , there is no added boost when WEP is applied and it wont hit its top speed at alt (18k ft)

[fruitbat]

good work Biggs

[Biggs]

Originally Posted by fruitbat

good work Biggs

just did another test with the mkIIa and they show (compared against the tests from SpitfirePerformace) that the mkIIa seems to be pretty much spot on for climb rate and top speed. (this plane really is fun to fly)

its the mkI thats off for some reason.

the other thing i noticed is that u cant fly the mkII in anything other than the black and white undersides... which is pretty ironic as is was the EARLIER mkIs that flew in that paint scheme...completely minor issue i know

LUTHIER lets get this mkI issue sorted please!

[fruitbat]

yep, the day/night scheme was changed between end of Dunkirk and beginning of the BoB, sometime in early June.

for the record The Spitfire Story, by Alfred Price lists the diff between 87 octane fuel and 100 as

"giving no improvement at or above 16,500 foot full throttle height of the merlin II and III engines fitted to the spitfires, below that altitude the maximum boost pressure could be raised from 6 1/4 pounds to 12 pounds without causing detonation in the cylinders; the resultant extra power increased the maximum speed by a useful 25mph at sea level and 34mph at 10,000 feet"

and being supplied to frontline squadrons from spring 1940.

[Biggs]

ABSOLUTE BONKERS!!!!!

the mkI is BETTER than the mkIa.... i did this twice cause i didnt believe it the first time...

at 18k WEP boost (4lb) coarse pitch.... i can hit ~260 IAS thats what...340TAS?


at the SAME at SAME boost and pitch... i can only hit 220 ISA in the mkIa

260IAS is still 20mph too slow but its a whopping 40 faster than the 'a' version (which should be the SAME as the mkI in terms of top speed)



Edit: i even think the climb rate is better for the mkI vs mkIa but im not sure