3,055 hp Tempest V ?

[Timppa]

Clostermann says in his book ("Une sacree Guerre !") that his unit had a few Tempests with 3,055 hp engines (war emergency power). His last Tempest, picked from RAF Warmwell around March 1945 "Grand Charles, JF-E" was one of them.

Sabre VII:
3055 hp/3850 rpm/2250ft
Hobson RAE single-point injection. Single-sided blower impeller. Almost 4000 hp developed on test. (1945)
The Hawker Tempest Page

Was that possible ?

 

[tomo pauk]

Here is an excerpt from the Williams' site:

Performance using +11 lbs. 3,850 rpm or the subsequently approved +13 lbs, 3,850 rpm is not reflected in the chart above. The Sabre IIB produced 2,420 bhp at SL using +11 lbs 3,850 rpm. Maximum speed of a Tempest V equipped with the Sabre IIB engine was 435 mph at 19,000 feet.

The difference between Sabres run at +9psi and +11 psi was some 200-250 HP, low gear, so the examples run at +13 psi should be good for ~2650 HP at SL?

 

[Shortround6]

From the same web site:

The Tempest VI prototype (HM595, which had earlier served as the Mk V prototype) was initially tested during February of 1945.

The Hawker Tempest Page

The 1946 edition of "Aircraft engines of the World" (publish spring of 1946) gives the power levels of a Sabre VA as take-off 2300hp/3850 rpm/12lbs boost and Military ratings of 2600hp/3850rpm/2500ft/15lbs boost and 2300hp/3850rpm/12,750ft/15lbs boost.

Lumsden gives a Sabre VII at 3055hp/ 3850 rpm/ 2250ft/20lbs boost.

More with water/methanol injection but it seems the Sabre VII was used in the Hawker Fury LA610 which originally flew with a Griffon 85 and Rotol six-blade contra-rotating propeller.

The Tempest VI shifted the oil cooler and carb intakes to the wing roots so the radiator could be made bigger without enlarging the radiator housing/fairing.

Chances of a service aircraft in the spring of 1945 having a 3000hp Sabre (with 20lbs boost) seem slim.

 

[Neil Stirling]

Not a Tempest V but a VI fitted with the 3,055hp Sabre VII. Performance here tempest | tiger moth | 1948 | 1660 | Flight Archive

Neil.

 

[Aozora]

The 1946 edition of "Aircraft engines of the World" (publish spring of 1946) gives the power levels of a Sabre VA as take-off 2300hp/3850 rpm/12lbs boost and Military ratings of 2600hp/3850rpm/2500ft/15lbs boost and 2300hp/3850rpm/12,750ft/15lbs boost.

Lumsden gives a Sabre VII at 3055hp/ 3850 rpm/ 2250ft/20lbs boost.

More with water/methanol injection but it seems the Sabre VII was used in the Hawker Fury LA610 which originally flew with a Griffon 85 and Rotol six-blade contra-rotating propeller.

The Sabre VII was the final Sabre development incorporating a larger supercharger impeller, and improved hydraulic supercharger clutch along with water/methanol injection and reinforced and improved internal components. Napier Sabre VII - Flight 1945

According to Flight, 1945, the maximum combat power rating (+17 lbs boost) with water injection was 3,055 hp @ 2,250 ft in MS Gear @ 3,850 rpm; 2,760 hp @ 12,450 ft in F.S gear @ 3,850 rpm. Sabre VII specifications

 

[Neil Stirling]

The Sabre VII at some time? Aircraft Engines of the World 1951, re-rated to +20lbs boost take-off 3,500hp.

Neil.

 

[Mike Williams]

Fwiw, Clostermann wrote in The Big Show, (Ballantine, New York, 1951), pp. 134-135: Maximum speed straight and level with + 13 boost and 3,850 revs.: 430 m.p.h. on the clock, i.e. a true airspeed of 440 m.p.h. In emergencies you could over-boost it up to nearly 3,000 h.p. and 4,000 revs., and the speed went up to 460 m.p.h.

F/O Ronald Dennis of 56 Squadron stated: All our machines were fitted with Rotol airscrews when the maximum rpm were increased to 3,850 from 3,700 and boost to +13 from +11... (The Hawker Typhoon and Tempest, (Aston Publications, Bourn End, Bucks, 1988) pp. 229-232)

I don't have Hp figures readily at hand for the Sabre IIB operating at +13/3,850, however, tomo's estimate seemes reasonable.

 

[Milosh]

W/C Beamont commented on using 150 fuel and 11lb boost > 415mph IAS @ 500ft.
pg 140 The Hawker Typhoon and Tempest, Mason

Would an extra 2lb of boost give a 15mph increase in speed?