Just love your logic Brain. :rolleyes: Did the extra boost directly cause rod, bearing or other engine component failures? NO!

Your quote of F/O Ronald Dennis of 56 Sqn says 13lb boost was used operationally.

Really? It says that the components of the prop were changed because the old ones could not absorb the added power, but does not say if this change was successful.

It's like to say "I installed 2 new video cards into my PC but the 300W APU was too weak and system failed: so I replaced it with a 450W APU".

How can you know if the system was stable after the change?

I understand that Sabre IIAs were cleared for +9 and Sabre IIBs (appearing in the automn 1944 IIRC) for +11.

I have also seen it claimed that IIAs were converted to IIBs, but I don't think I have ever seen evidence of that. Have you seen any...?

What is the source of the pilot quote and what period this quote is referring to?
Was it during the war or the comment was made in the post-war period?

I'll have to try to dig something out. There are a few documents kicking about on the internet that make mention of this, as well as noting the Series I machines (first 94 - 2 already being series II spec) being upgraded to series II (2nd batch).

That all said, for the purpose of IL2, the Sabre IIB 11lbs and 13lbs varients have been made available else where. Maybe they can do some similar justice to the 152C....

Ask Brain.

Do you really believe in what you wrote? :shock:

Tempests had a lot of engine problems in 1944, especially about valves and backfires. It's a thing everyone interested in that plane knows very well.
At the same time, everyone interested in that plane knows that engine troubles decreased months after months (according to "Typhoon and Tempest Aces of WWII" by C.Thomas, the Sabre was already "accettably reliable" during the V-1 battle in summer 1944).

But there is NO news about troubles caused by Rotol propellers!

Just like, BTW, there is no news of troubles caused by +11lbs boost during the final months of the war nor any news of Tempests reverting to +9lbs.

The only question to ask is "how many Tempest used +13lbs boost and Rotol prop?", not "was it successful?".

BTW, on the same wwiiaircraftperformance page that reports Dennis quote you can find this too:

"On the 30th March, six days later, I came back to Volkel in time to go to Warmwell in the duty Anson to choose a beautiful brand-new Tempest with the new Rotol airscrew. Two days later I was posted O.C. "A" Flight, No. 3 Squadron in 122 Wing (at B.122 Rheine)." (Pierre Clostermann)

Its probable that "beautiful brand-new Tempest" belonged to the fourth production batch, delivered from 1/45 to 6/45, that consisted of 201 planes built ("Hawker Tempest", +4 Publications, pag. 3).

It seems likely to me that there were much more than a handful of +13lbs in 1945, although it's not easy to guess how many.

A seemingly well informed guy wrote this some days ago, on another forum, talking about Sabre IIc engine (which I believe, being the most powerful of the II series, was usually coupled with the Rotol prop):

"[...]
The IIC was fitted to Typhoon Is, IBs and Tempest Vs.
[...]
As to how many IICs were fitted to the above, I don't think we'll ever know, as Sabres were the subject of continual modification programmes and aircraft were frequently re-engined at unit level with the latest approved version. However, Typhoon and Tempest V Srs 2 production did not extend beyond WW2 so some were definitely fitted with Sabre IICs (if the book ['British Piston Aero Engines' by Alec Lumsden] says IICs were fitted to Typhoons and Tempest Vs you may be sure that it's correct - its information is taken from company records)".

So, it's likely the same uncertainty about numbers of IIc regards Rotol props too.
But I think their number could be higher than, for example, the numbers of Ta152H that reached service (whereas, AFAIK, Ta152C never was operative!).

Also Closterman state in his book he was using the tempest at 13lbs and giving power figures that match quite well those of the Sabre IIC at 13lbs.