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Hi crumpp, I've no issue with the math. Frankly I'm not scooled up in the formulae to critique it anyways. My interest is more as a historian, rather than engineer.

Can you advise why the Merlin power assumption is around 990bhp? And, when you use, say the Merlin 3, the auto prop and/or the 100 octanes, how do the graphs look?

Sorry if this creates loads of work....

Quote:

IvanK says:
One more from the RAE clearly showing better turn performance of the Spitfire in all regimes.

With landing gear and flaps down......

Quote:

Originally Posted by Crumpp (Post 462305)

With landing gear and flaps down......

Crummp, when quoting other people in the thread, please could you leave in the name of the person you're quoting as above? Quoting people without reference to who it is makes following the conversation very difficult.

Many thanks. :)

Quote:

Originally Posted by Crumpp (Post 462305)

With landing gear and flaps down......

At 300MPH?

Quote:

Psyle says:
Sorry if this creates loads of work....

No problem at all. In fact I am going to clean up the sheet and post it so others can use it. It just runs the math for the conditions given.

I wish I was more computer savvy to make it more user friendly. Perhaps some in the community can improve upon it.

The 990 hp comes directly from the RAE.

Quote:

SUMMARY OF TRIALS

AEROPLANE Spitfire I No. N.3171
SPEC. NO. 16/36
CONTRACTOR Vickers-Armstrong (Supermarine)Ltd.

TYPE Landplane DUTY Single Seater Fighter.

ENGINES. Merlin III Normal B.H.P 950/990 at Rated Altitude 12,250 ft

http://www.spitfireperformance.com/n3171.html

Once I get good engine data on 100 Octane, I will do the estimate.

On these charts the data does not line up. The FTH do not even come close to assume RAM effect.

Level speed - FTH MS Gear = 11,000 ft

http://www.spitfireperformance.com/s...-rae-12lbs.jpg

Engine power estimate at Vmax (RAM effect) shows a FTH MS Gear = 8,000 ft

http://www.spitfireperformance.com/merlin3curve.jpg

Not saying the data is bad, just that this engine does not match this airplane. We need to find the same engine in the same airplane to get good data points.

Quote:

bongodriver says:
At 300MPH?

Exactly....

Once again, explain the assumed values of CLmax on the RAE chart. I am listening.

Quote:

ATAG DUTCH says:
Crummp, when quoting other people in the thread, please could you leave in the name of the person you're quoting as above? Quoting people without reference to who it is makes following the conversation very difficult.

Sure thing.

Quote:

Originally Posted by Crumpp (Post 462310)

Thanks. I think this would be a good idea.
At least then we are all able to work to the same assumptions and review each others work. It's be good to see how the manipulation of one or more of the variables influences tge overall outputs.

Crummp, when the RAE refer to "normal bhp", do you know what the term "normal" refers to. Are there other bhp values which might be arrived at which are outside of that description?

Quote:

Originally Posted by Glider (Post 462294)

I don't know about rubbish, that is a bit strong, but its worth remembering that it was soon changed for the DB 605 and the Germans wouldn't have done that without a reason. I can only assume that it lacked development potential

Uhmm... the DB 605 is the same thing as the 601, but with "bored-up" cylinders... which had a larger diameter by a mighty [i]4 milimeter (0,154 inch for you guys).