FM's the State of Play with empasis on Climb performance.

[Crumpp]

Crumpp and the RR Merlin:

"THAT IS WHY YOU HAVE PILOT ANECDOTES OF FLYING AT +16 LBS ON 87 OCTANE!"

Seadog....

Read, it is from your own post:



http://forum.1cpublishing.eu/showpos...postcount=1696

[Crumpp]

The flight tests were done at mission weights as close as possible to the source documentation.

Ok as close as possible is not exact.

ROC = Excess POWER / weight

The difference in weight will produce a proportional difference in climb rate. If you are 1% off in weight you will see a 1% increase in climb rate.

[IvanK]

Of course its not exact but the trouble is within the limits of the Sim you cant always physically get the actual weight !! That is the case with the Spitfire.

Crumpp in post #14 YOU stated "The Relative performance is about right and it looks like people are nitpicking IMHO" !!.

The closest I could get to the correct weight was 75Lbs LESS than that used in the RAE test. If you actually look at the test you would see that with the CLOD Spit at 75Lbs less weight its still under performing by a considerable margin. So who is nitpicking now ?

[Seadog]

Originally Posted by Crumpp

Seadog....

Read, it is from your own post:

There's nothing in that excerpt that states the engine could run at 16lb boost on 87 octane fuel...in fact there's nothing about 87 octane in it at all.

[camber]

Thanks IvanK,

Your climb tests tell a similar story to my speed at alt data.

Originally Posted by Crumpp

Seadog....

Read, it is from your own post:



http://forum.1cpublishing.eu/showpos...postcount=1696

The reference to +12psi and an external bleed hole confirms that the boost cutout used by Pilot Wilkie is the type modified for 100 octane emergency power. Blocking the drilled bleed hole returns the boost cutout to it's original operation (giving direct throttle control to the pilot) and hence the ability to get higher boost pressure than +12psi (on 100 octane).

camber

[Robo.]

IvanK - thank you very much indeed! We've been doing some testing withe the RAF fighters against the 109s and we've also found serious discrepancies regarding performance.

Your time is much appreciated!

[Crumpp]

The reference to +12psi and an external bleed hole confirms that the boost cutout used by Pilot Wilkie is the type modified for 100 octane emergency power. Blocking the drilled bleed hole returns the boost cutout to it's original operation (giving direct throttle control to the pilot) and hence the ability to get higher boost pressure than +12psi (on 100 octane).

Not if you read the 1937 Flying Notes. It talks about this same modification independent of fuel. The boost override could allow the pilot to reach boost pressure which caused detonation and this a typical modification.

There is no way of telling from an anecdote the details of the engine modifications.

Using a bleed hole is a very common method to control boost pressures. This is the same thing that BMW took when increasing the BMW801D series to 1.58ata/1.65ata. They just drilled the hole on the other side of the diaphragm.

Crumpp in post #14 YOU stated "The Relative performance is about right and it looks like people are nitpicking IMHO" !!.

The closest I could get to the correct weight was 75Lbs LESS than that used in the RAE test. If you actually look at the test you would see that with the CLOD Spit at 75Lbs less weight its still under performing by a considerable margin. So who is nitpicking now ?

I am wondering what your expectations are here. Yes, the relative performance is about right. What is the issue???

The error looks to be on the order of about 10% which is not bad for climb performance.

You are asking the developers to correct performance to a standard day, too. They should be moving the opposite direction and modeling performance on a summer day.

Of course your climb rates are going to be significantly reduced at a high density altitude.

I would ask questions like:

"Why is my level speed matching performance corrected to standard on a high density altitude day?"

"Why is my radiator temperature hitting the upper limits in level flight on maximum continuous?"

"Why can I asymmetrically overload the airframe at 400 mph and nothing happens?"

There is a lot bigger fish to fry for the programmers than a small error in specific climb rates.

[IvanK]

So Crumpp what then was the point of your comment in post #28 "Ok as close as possible is not exact." ?

I do actually agree with you in your comment on the Structural strength model (or lack of) in CLOD,and the other questions you propose as well. Other than standard Atmosphere question they have all been brought up directly with the devs a long time ago. When or if the devs decide to do something about them is for them to decide.

[Robo.]

Originally Posted by Crumpp

I am wondering what your expectations are here. Yes, the relative performance is about right. What is the issue???

No it is not! Please have another look at the Spec graphs of E-4 and Mk.IIa and then have a look at the tests. You see?

Originally Posted by Crumpp

"Why is my level speed matching performance corrected to standard on a high density altitude day?"

"Why is my radiator temperature hitting the upper limits in level flight on maximum continuous?"

"Why can I asymmetrically overload the airframe at 400 mph and nothing happens?"

Agreed on all this. I hope all this issues will be adressed at some point.

Originally Posted by Crumpp

There is a lot bigger fish to fry for the programmers than a small error in specific climb rates.

The error is not small! The gap is now ridiculous and very much unhistorical. Perhaps it does not matter to you for you don't actually fly this sim.

[camber]

Originally Posted by Crumpp

Not if you read the 1937 Flying Notes. It talks about this same modification independent of fuel. The boost override could allow the pilot to reach boost pressure which caused detonation and this a typical modification.

Absolutely disagree but this discussion occurred before and my position is essentially the same as Banks. No point to reopen the argument here.

http://forum.1cpublishing.eu/showthr...t=32190&page=2