Inaccurate performance data for BOB fighters in COD comparing to RL data

[NZtyphoon]

Fair enough I missed #205; here's #205

Originally Posted by TomcatViP

Wrong. See my post above and data pasted bellow. You need to take into account the s/c !

MerlinXX !

ALT(ft) SHP BHP (diff correspond to the power used to drive the supercharger)
15K 1267 1048
20K 1298 1073
20K+ 1362 1126
25K 1162 960
30K 945 778
35K 700 568


More over the subsequent Merlin (the XX) developed to give more power to the Hurri (what the RaF felt was more a need) was limited to 9lb at 20Kft but 12lb in T.O/Emergency


I think that you are confounding higher grade and NOS and don't forget all the cooling prob with the Merlin in the RAFFC's fighters

Quitely again as I hve said it does not fit any logics.

~S!

This is a post about the Merlin XX, which is a completely different engine from the III, using a two-speed supercharger which drew more power than the single-stage single speed unit of the III:
otherwise there is No evidence provided that R-R routinely tested its engines without superchargers, No documentation, No mention of a History of Rolls-Royce.

[TomcatViP]

Originally Posted by NZtyphoon

Fair enough I missed #205 because it was so tedious reading all of your nonsense over again; here's #205


This is a post about the Merlin XX, which is a completely different engine from the III, using a two-speed supercharger which drew more power than the single-stage single speed unit of the III:
otherwise there is No evidence provided that R-R routinely tested its engines without superchargers, No documentation, No mention of a History of Rolls-Royce.

I quoted the exact title of the book elsewhere (sry not with me as for now). It's one of the RR heritage trust. It's a study extracted from RR sources and internal documentation.

As I said, this small book written in 1941 explain why RR had to create new methods to predict the perf of a S/C Engine at alt due to the divergences of predicted perf and the real ones achieved during flight test. The authors were the very same guys conducting the work at the time.

It is also explained how the US was slightly in advance in that way. But also why RR conducted that work as improvement were still on demands.

The base engine to conduct this work was the NEW MerlinXX flight tested in a Hurricane II.

There is a lot of interesting curves that I hve re-used in my post (but no scan). Most notably no perf test was seen using the 12lb boost when top performance was the very base of that work

The book itself is cheap (10 to 20$ ?) and can be ordered simply via amazon if I do remind well. I had to wait 1 or 2 month to get a new print out of the roll. You may read (or ask ?) Viper2000 posts with whom I heard first abt that book.

~S

[Gabelschwanz Teufel]

It it patently obvious that many squadrons used 100 octane fuel. How many? Were they confined to 11 group or were they throughout fighter command? We haven't been able to determine that exactly, yet. But to deny it was used at all is to deny documented historical fact

Quote:
"The spitfire were not so succesfull against the 109s in other theaters. At mediterranean and Afrika the allied resources are bigger. And the RAF suffered heavy loses in Afrika and Malta. The failure of the Luftwaffe in this scenarios was mainly because they were outnumbered and low of fuel. And they performed very well. And the spitfire was there."

As an aside, Spitfires (and Hurricanes) initially used in the middle east suffered a considerable performance penalty due to the enormous "Volkes" filter that was attached to keep sand out of the intakes. The "Aboukir" filter that was developed later caused less of a performance issue.

[TomcatViP]

Originally Posted by TomcatViP

I quoted the exact title of the book elsewhere (sry not with me as for now). It's one of the RR heritage trust. It's a study extracted from RR sources and internal documentation.

As I said, this small book written in 1941 explain why RR had to create new methods to predict the perf of a S/C Engine at alt due to the divergences of predicted perf and the real ones achieved during flight test. The authors were the very same guys conducting the work at the time.

It is also explained how the US was slightly in advance in that way. But also why RR conducted that work as improvement were still on demands.

The base engine to conduct this work was the NEW MerlinXX flight tested in a Hurricane II.

There is a lot of interesting curves that I hve re-used in my post (but no scan). Most notably no perf test was seen using the 12lb boost when top performance was the very base of that work

The book itself is cheap (10 to 20$ ?) and can be ordered simply via amazon if I do remind well. I had to wait 1 or 2 month to get a new print out of the roll. You may read (or ask ?) Viper2000 posts with whom I heard first abt that book.

~S

The book ref. :

Performance of a Supercharged Aero Engine
Hooker, Stanley 1872922112
Rolls Royce Heritage Trust

http://www.amazon.com/Performance-Su...6&sr=8-2-fkmr0

(seems the price has increased - the bill I dug out of my archives says 6.53€ !)

Regarding the Spit II, I didn't heard any of your commentaries regarding the roll out date (august) and service intro (sept late)

[41Sqn_Banks]

Originally Posted by TomcatViP

Regarding the Spit II, I didn't heard any of your commentaries regarding the roll out date (august) and service intro (sept late)

http://www.spitfireperformance.com/no611-orb.jpg

16/8/1940 "A" Flight used the new Spitfires for the first time in operations.

Can you provide a source for the introduction of Spitfire II in OTU, e.g. which OTU received Spitfire II?

[Al Schlageter]

Originally Posted by 41Sqn_Banks

Can you provide a source for the introduction of Spitfire II in OTU, e.g. which OTU received Spitfire II?

P7280 IIa Morris MXII First Spitfire by Nuffield AMDP AAEE 27-6-40 diving trials with 7lb inertia wt on elev control syst. hand trials AST 25-10-40 DTD AAEE 29-10-40 403S 17-7-41 457S 4-10-41 61OTU 5-1-42 FACB 29-4-42 61OTU 2-7-43 trials with blister hood 10-43 comparison trials with N3171 (MkI) Spun into ground out of cloud Crickheath Farm nr Oswestry CE 15-9-44

P7281 IIa Morris MXII 6MU 17-6-40 612S 27-8-40 611S 27-8-40 41S 24-10-40 54S 22-2-41 616S 10-7-41 417S 26-1-42 15OTU 15-2-42 57OTU 30-7-42 CB 22-4-43 SOC 23-1-44

P7282 IIa Morris MXII 6MU 26-6-40 611S 22-8-40 41S 24-10-40 shot down by Bf109 P/O Draper injured C3 30-10-40 SOC 14-11-40

P7283 IIa Morris MXII 8MU 1-7-40 611S 26-8-40 41S 24-10-40 C2 ops 17-11-40 54S 12-2-41 234S 3-7-41 152S 28-10-41 8FTS 13-6-43 10AGS 17-4-45 FTR ops 17-5-45 SOC 18-6-45

P7284 IIa Morris MXII 8MU 7-7-40 611S 26-8-40 41S 24-10-40 C2 ops 26-10-40 54S 22-2-41 308S 14-7-41 610S 11-9-41 3ADF Spun into ground in circuit Valley CE 2-11-41 SOC 5-12-41

P7285 IIa Morris MXII 8MU 1-7-40 266S 5-9-40 603S 7-10-40 Shot down by Bf109s 16m E of Dover 8-10-40 F/O Kirkwood missing

P7286 IIa Morris MXII 9MU 13-7-40 152S 17-7-40 603S 17-10-40 shot down by Bf109 P/O Maxwell 27-10-40 AST AAEE 16-1-41 trials with Rotol constant-speed prop Morris rad and inertia weight 234S 12-5-41 VA 3-7-41 66S 31-7-41 152S 3-9-41 Overshot landing into fence Swanton Morley CAC 16-9-41 ASTE SOC 10-11-41

more @ http://www.spitfires.ukf.net/p003.htm

[41Sqn_Banks]

Originally Posted by Al Schlageter

more @ http://www.spitfires.ukf.net/p003.htm

Thanks, I checked several pages, the earliest date I found was December 1941 were a couple of Spitfire II were assigned to 61OTU. The majority was 1942 or later. I didn't find a single aircraft that was assigned directly from Maintenance Unit (MU) to OTU, all were transferred to operational squadrons first.

[NZtyphoon]

Originally Posted by TomcatViP

The book ref. :

Performance of a Supercharged Aero Engine
Hooker, Stanley 1872922112
Rolls Royce Heritage Trust

http://www.amazon.com/Performance-Su...6&sr=8-2-fkmr0

(seems the price has increased - the bill I dug out of my archives says 6.53€ !)

Thanks for that, I'll do some amazoning.

[Al Schlageter]

Glider

Unless of course you believe it to be true and that the RAF had Mk II spits in July 1940 with 2 x 20mm and 4 x LMG which is what your pilots notes say.

Barbi

"P9504... still had four of the original Browning MG mountings in the wings. It was used to test a trial installation of two Hispano cannon and four Browning guns... within days a second Spitfire, X4257 had a wing built from scratch, with the new armament and service trials begun on 20 August. Five days later R6761, 6770,6889,6904 and 6919 were withdrawn from No.19 and modified to the same standards. etc.."

Seems Barbi doesn't know the difference between July and August.

X4257 Ib 1037 EA MIII FF 16-8-40 6MU 20-8-40 first Spit with 'B' wing Type 340 AMDP EA 30-8-40 RAE 3-9-40 AAEE 20-10-40 1CRU new eng 8MU 15-11-40 AFDU Duxford 11-1-41 R-RH 10-2-41 M45 fitt redesignate FVB 92S 16-2-41 service trials engine failed crashed Maidstone 19-3-41 AST 411S 8-11-41 AAEE 1-42 R/T function trials at high alt with R7120 (FVI) 242S 25-9-42 VASM 5-4-43 fuel syst mods wing stiff 118S 2-7-43 64S 25-9-43 power loss force-landed hit obst nr Lodiswell S Devon CE SOC 3-7-44 F/O W Smart killed

[Glider]

He obviously will not mind the RAF using the IIB in July 1940. Can I have one please.

Being serious for a moment, do you know when the first IIB was built, the ones quoted are Spit IB's

Another small point is that anyone who has seen the RAF Pilots Notes will see that the format of the one that Kurfurst quotes, isn't an original document. The format didn't change until well after the war. My notes for the Hunter are still in the WW2 standard layout.