Spit/109 sea level speed comparisons in 1.08 beta patch

[IvanK]

Now lets look at this Clmax discussion which Crumpp claims the RAE cocked up. Lets look at some other peoples estimates for Spitfire Clmax values.

How about we start with NACA ... we will use that very same report Crumpp that you are so smitten with that you used in setting up the "Spitfire Dangerous Stability thread". Here is NACA's estimate on Clmax



So at Cruise power (3.75lbs boost 2650RPM) in clean configuration they come up with 1.68 (Recalling that the RAE plot is based on +6.25Lbs/3000RPM)


Then lets look at the RAE document they wrote in response to the NACA report:



Interestingly the RAE methodolgy is slightly different to NACA's (Trailing versus Pole with swivel head) the RAE came up with Clmax on the glide (power off) of 1.36 and at max power of 1.89. The RAE Blue Turn plot uses a Clmax value under full power of 1.87

Of course we know the NACA report was based on a Spitfire MKVA so there will be some variance to the numbers of a Spitfire MKI but it does give some validation of the RAE determined Clmax under power values.

The NACA Spitfire MKVA document was good enough for you Crumpp in the stability argument regarding the MKI so I assume its an acceptable reference in this discussion ?