Spit/109 sea level speed comparisons in 1.08 beta patch

[Crumpp]

That chart was not used because it does not align. The engine chart you linked already includes RAM effect at Vmax.


That means the FTH should match. Not be close or have the same margin of error, but match if that is the correct engine data.

I used the power figures as listed in the flight reports NOT a seperate engine curve that does not match the performance data.

[Crumpp]

[41Sqn_Banks]

I know that, I can read. You asked how the engine data align with the speed graph. They align with an consistent altitude difference of about of 2,000 ft.

The altitude difference between the FTH in the charts can be explained by a different level flight speed. E.g.
Hurricane I has a FTH of 17,750 ft at 316 mph.
Spitfire I has a FTH of 18,600 ft at 364 mph.

As we see the 50 mph speed difference results in a drop of 1000 ft for the FTH.

There is nothing contradicting in the charts ...

[Crumpp]

I know that, I can read.

Then what is the issue with the data not aligning?

The altitude difference between the FTH in the charts can be explained by a different level flight speed. E.g.

It will align. If you looked at other aircraft and not just confined yourself to one specific type, you would see this the case.

A speed difference is not going to account for a 2000 ft increase in FTH.

How do you explain the fact this chart comes from an investigation of performance with an experimental high altitude engine.

The chart exactly matches the one found in:

Messerschmitt Me. 109

Handling and Manoeuvrability Tests

BY

M. B. MORGAN, M.A. and D. E. MORRIS, B.SC.

COMMUNICATED BY THE PRINCIPAL DIRECTOR OF SCIENTIFIC RESEARC (AIR)

MINISTRY OF SUPPLY

__________________________________

Reports and Memoranda No. 2361

September 1940*

http://kurfurst.org/Tactical_trials/...ls/Morgan.html

[Crumpp]

Originally Posted by 41Sqn_Banks

I know that, I can read. You asked how the engine data align with the speed graph. They align with an consistent altitude difference of about of 2,000 ft.

The altitude difference between the FTH in the charts can be explained by a different level flight speed. E.g.
Hurricane I has a FTH of 17,750 ft at 316 mph.
Spitfire I has a FTH of 18,600 ft at 364 mph.

As we see the 50 mph speed difference results in a drop of 1000 ft for the FTH.

There is nothing contradicting in the charts ...

The data matches the same fan plot in another report on a Spitfire equipped with a Merlin XX engine.

AFAIK, the Spitfire Mk I was equipped with the Merlin III engine.

[Glider]

I have put in a request to the Rolls Royce Heritage Trust part of Rolls Royce to see what they say. The NA don't seem to have anything that would satisfy everybodies requirements. I wouldn't hold your breath as it might take forever but should at least deliver a definitive reply.

[Crumpp]

I shall do the math to prove that 400kph was the cruise speed

Do you know where cruise speeds are located on the Power and thrust curves?

Need me to show you.....????

[Crumpp]

Spitfire III, AFAIK only the prototype was built.

[Robo.]

Originally Posted by Crumpp

Do you know where cruise speeds are located on the Power and thrust curves?

Need me to show you.....????

No need, thank you.

All I said was that you were wrong in your statement that 400kph fixed trim setting was due to the 'good speed for dogfight' reason

http://forum.1cpublishing.eu/showpos...&postcount=323

Originally Posted by Crumpp

When you calculate out the performance, it is easy to see why Mtt defaulted the trim to 400kph.

That is a very good speed to dogfight the airplane.

It is a very good speed to dogfight the airplane, but that has nothing to do with the sustained turn debate (in practical reality of an actual air combat). I explained that earlier. It is also not the reason for default trim settings, that reason was actually cruise speed at 1.15ata @ 2200U/min.

Here again:

Originally Posted by Crumpp

Why do you think the trim on the Bf-109 is set to 400 kph IAS???
You do understand they can trim the aircraft for whatever speed they desired?? Having a fixed trim condition is a great way to set the combat speed for your airforce.

Please don't mix up facts as they suit you to prove your bizzare theories.

[Seadog]

Originally Posted by Crumpp

http://imageshack.us/a/img19/1355/merlin3curve1.jpg

Merlin II/III could hold 12lb boost to over 10,000ft in a Hurricane and higher in a Spitfire: