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

[TomcatViP]

The much modified SpeedFire did run operational reconnaissance missions on a couple of occasion. She was used for high speed low deck run on the French coast fitted with cameras (620/50 kph if I do remind well)

The consumption of her engine prevent her to be flown much deeper.

The pilot (a test pilot if I do remind correctly) had to care about the level of water left in the specific rads (vapor blown away) with great attention (well planned missions). Despite some concerns at the beginning he did not have any serious problem during his attempts.

Le Fana de l'aviation published the story in France some years ago. It might hve been a translated article extracted from US/UK sources.

Regarding the HP of the Merlin as of NZT sources it : He is confusing SHP and BHP. It was a standard use in RR to give the power of an engine without the charger fitted as the methods used to calculate the true corresponding power at alt from a bench test ran on the ground were not reliable (source RR - already mentioned by myself somewhere in the thread).

[Al Schlageter]

Originally Posted by TomcatViP

Regarding the HP of the Merlin as of NZT sources it : He is confusing SHP and BHP. It was a standard use in RR to give the power of an engine without the charger fitted as the methods used to calculate the true corresponding power at alt from a bench test ran on the ground were not reliable (source RR - already mentioned by myself somewhere in the thread).

How ever was the engine ever run to obtain the hp number as the supercharger was between the carb and the cylinders?

As Barbi and Eugene are so positive that 87 octane fuel was still in widespread use by RAF FC, they should have no trouble listing the squadrons, and the bases they flew from, that were still using 87 octane fuel late in the BoB.

As for Barbi's comment of fuel consumption, he is no doubt referring to the useless garbage graph (no source for the data points ever given) he posted earlier in this thread. Useless garbage because the consumption of 87 octane fuel includes that other RAF Commands (Coastal, Bomber, Training et al).

There's of course this paper of 7 August that supposed to 'authorize' all Commands for using 100 octane

Now this statement shows what a double standard Barbi has as he uses a German document, and [v]ONLY[/b] this document, giving authorization for 1.98ata use to 4 Gruppen with the Bf109K-4 and even goes on and speculates that other K-4 and G-10 units also used 1.98ata boost. This contradicts Eugene's emphatic statement that German units never ever did modifications without official authorization.

It is not known if and how many units had converted to 1,98 ata manifold before that order came, but it should be noted these units, in particular III./JG 27, III./JG 53 and IV./JG 53 were the major users of the Bf 109 K-4 in the Lufwaffe. The other units effected are not known at present, but given the abundance of photograph depicting G-10 and K-4 fighters belonging to other units, marked for C-3 fuel use - a likely sign of the DC engine at 1,98 ata - the boost increase was likely not limited to JG 27 and JG 53 alone.

[NZtyphoon]

Originally Posted by TomcatViP

It was a standard use in RR to give the power of an engine without the charger fitted as the methods used to calculate the true corresponding power at alt from a bench test ran on the ground were not reliable (source RR - already mentioned by myself somewhere in the thread).

Evidence please?

[NZtyphoon]

The Merlin tested in the Hurricane ran for 8 1/2 hours on 100 Octane fuel at 12 pounds boost, but the test was terminated after 49.5 hours by a glycol leak into one cylinder. The document goes on to note that this problem was rectified by modifying the cylinder head joints, a modification which was retrofitted to earlier Merlins and would have been incorporated into later Merlins. ( paras 4 & 6)

"It will be noted from the Service reports that an approximate increase in speed, due to the use of emergency 12 lbs. boost, of 28/34 m.p.h. is obtained depending on the altitude flown up to 10,000 feet." (para 8.)

This most likely applys to both the Hurricane and Spitfire. Gleed, below, 19 May 1940, notes an increase of 30 mph for his Hurricane.

"The modifications to the boost control cut out to limit the maximum boost to 12 lbs. sq. in are simple and in hand (otherwise full throttle would give about 17 lbs. sq. in.)" para 9.

[Osprey]

I thought Kurfurst had "only a passing interest" in the RAF?

[NZtyphoon]

Originally Posted by TomcatViP

You shld write comics. You will hve an huge success.

It has been alrdy explained and can be found in many documents.

I myself illustrated this meaning right her ein this thread by linking to a 1954 FLIGHT articles detailing the evolution of teh Merlin eng during the war with details of wich octane was used.

There is also a second article of FLIGHT that I linked about a respective study of a He111 engine and the Merlin where teh author explained that the Brits eng discovered that the remaining trace of fuel found inside the studied German engine showed that the LW probably was using a fuel withe better octane grade than what RAF used at the time.The article clearly says that it was 92 octane in the German bomber.

More over I hve a thousand times explained and showed that there is no sense to believe that 100 octane will provide a tremendous augmentation of pow in an eng that was not specifically built for that fuel.

Here is a modern example with Turbo Tech (no power eng needed to drive the compression process) : http://wn.com/octane_rating?orderby=..._time=all_time

As I hve alrdy says I don't know what to write more. What 's for sure is that I am loosing my time at a ... 100% rate !

Yes Mr Tomcat, I'm sure you're convinced in your own mind that you're right, so there's no point in discussing the matter any further with you is there? Meantime, your Flat Earth Society friends are waiting for you to make your maiden speech to the Venerable Coven of Witches and I believe your pet ostrich has buried its head in sand - again.

[TomcatViP]

Originally Posted by NZtyphoon

Yes Mr Tomcat, I'm sure you're convinced in your own mind that you're right, so there's no point in discussing the matter any further with you is there? Meantime, your Flat Earth Society friends are waiting for you to make your maiden speech to the Venerable Coven of Witches and I believe your pet ostrich has buried its head in sand - again.

Get some fresh air NZT.

Did someone at least watch the Impreza example ?

[41Sqn_Banks]

Originally Posted by TomcatViP

Get some fresh air NZT.

Did someone at least watch the Impreza example ?

Can you provide the exact link, your previous link just showed a search result and pointed to a video called "Octane Rating - Explained", didn't find something on the Impreza.

[TomcatViP]

updated (see above)

[Al Schlageter]

Originally Posted by TomcatViP

More over I hve a thousand times explained and showed that there is no sense to believe that 100 octane will provide a tremendous augmentation of pow in an eng that was not specifically built for that fuel.

So why do the instructions for the mods to the engine for the use of 100 octane fuel not mention anything about beefing up the engine? Just maybe it is because beefing up the engine wasn't required as it was already strong enough.

Even you gospel, FLIGHT, says the early Merlin was ran at 22lb boost.