Kermit Weeks Tempest MkV

James D · **Posted:** Wed Feb 28, 2024 3:53 pm

Part 2 is up, looking at both Sabres and the fuselage...
https://www.youtube.com/watch?v=LVm7jCRARD0

Richard Grace has an interesting insight into picking out the better of the two engines to use.

DH82EH · **Posted:** Wed Feb 28, 2024 7:37 pm

Clearly, one can tell, that Richard has already done lots of homework.
I can think of no one better equipped to complete the rebuild of this Tempest V.

blurrkup · **Posted:** Thu Feb 29, 2024 6:31 am

Watched it this morning and was just about to update here when I saw somebody already had. Think this will be spectacular restoration when completed and hope that it gets to fly and attend some shows in the UK before going back to Kermit as long as it does come over here. Wonder what the UK Typhoon project is going to do about their engine. It sounds like from what Richard was saying that one guy they had asked to restore it said no due to it being an early engine.

Archer · **Joined:** Tue Nov 30, 2004 3:13 pm **Posts:** 368

Very interesting video! The engine situation is certainly an interesting one. It made me go and look up some Sabre specs:

Quote:

SABRE I, 2,000 hp, (1939), Type E107, 24-cylinder, horizontally opposed, H-shaped, 70-30 per cent water/ethylene-glycol cooled, sleeve-valve. Bore/stroke 5.0 x 4.75 in. Vol. 2,240 cu in. (127 × 120 mm. Vol. 36.65 litre). Compression ratio 7:1. Two-speed, medium/fully supercharged, 4.68: and 5.83:1. Geared, spur .274:1. L.H. tractor-drive. Plessey Coffman cartridge starter. (Typhoon F.18/37, I)

SABRE II, 2,300 hp, (1940), (experimental .322 reduction gear). E115. Plessey Coffman cartridge starter. Length 82.25 in; width 40 in; height 46.0 in. (Typhoon II, Tempest I)

SABRE IIA, 2,235 hp, Sabre I modified for mixed matrix radiators. Similar to Mk VB . Altered ignition and plugs. Supercharger ratios 4.48:1 and 6.26:1. Reduction gear ratio .274:1. (Typhoon I, IB, Tempest V)

SABRE IIB, 2,400 hp, similar to Mk IIA, S.U carburettor. (Typhoon I, IB, Tempest V)

SABRE IIC, 2,065 hp, similar to Mk VII but with supercharger ratios 4.73:1 and 6.26:1. S.U. AQV carburettor. (Typhoon I, IB, Tempest V)

SABRE III, 2,250 hp, similar to IIA, to suit Firebrand. Higher rpm.

SABRE IV, 2,240 hp, (1943), as Mk VA with R.A.E.-Hobson fuel injector. (Typhoon I, II, Tempest I, V)

SABRE V, 2,600 hp, (1944), E121. Development of Mk I. Increased boost, redesigned supercharger and induction system, supercharger ratios 4.68:1, 5.83:1. R.A.E. BI/NS2 fuel injection. (Tempest I, V, VI)

SABRE VA, 2,600 hp, as Mk V with Hobson-R.A.E. NS4 fuel injector. Inter-connected, single-lever propeller and throttle controls. Length 82.25 in; width 40.0 in; height 46.0 in. (Tempest VI).

SABRE VI, 2,310hp, similar to Mk VA, with Rotol geared cooling fan and annular radiator.

SABRE VII, 3,500 hp, E118, 122, generally similar to Mk VA, except for being strengthened to withstand higher powers available with water/methanol injection for take-off and combat power. Length 83.0 in; width 40.0 in; height 47.75 in.

Source: "British Piston Aero-Engines", Alec Lumsden (1994)

Looking at this list and the specs, it sounds like the green Sabre that was discussed in the video may be a Sabre V, with the other one being an earlier Sabre II or something along those lines. The Tempest V used Sabre IIA, IIB or IIC engines according to Wiki... but putting a later model engine in it would make sense if at all possible. It would make it a Tempest VI equivalent I guess.

Michel Lemieux · **Posted:** Thu Feb 29, 2024 8:29 am

I was really surprised when he said it was a 1000 hours TBO engine later on!!!

Archer · **Joined:** Tue Nov 30, 2004 3:13 pm **Posts:** 368

The Sabre engine got a bad reputation due to the early, less developed variants and the often discussed sleeve issues with these engines. It would be interesting to look at the post WWII service of the Tempest and the reliability of the Sabre engines. Target tug variants flew into the 1950s IIRC, they would not have continued to fly a type for more than five years post war with the reliability seen in those early to mid WWII years.

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11282

30 liters is about 1830 cubic inches. Not very big! A late model R-1820 (like might be used in a later T-28) puts out 1425 HP as I recall.

mdwflyer · **Posted:** Thu Feb 29, 2024 3:52 pm

bdk wrote:

30 liters is about 1830 cubic inches. Not very big! A late model R-1820 (like might be used in a later T-28) puts out 1425 HP as I recall.

I did that math when he said it on the video, but I think he said "guessing about 30 litres"

Vol. 2,240 cu in. (127 × 120 mm. Vol. 36.65 litre)

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11282

mdwflyer wrote:

bdk wrote:

30 liters is about 1830 cubic inches. Not very big! A late model R-1820 (like might be used in a later T-28) puts out 1425 HP as I recall.

I did that math when he said it on the video, but I think he said "guessing about 30 litres"

Vol. 2,240 cu in. (127 × 120 mm. Vol. 36.65 litre)

2,240 for the Griffon as well. A lot of power for the displacement. I'd sure like to look inside one.

DH82EH · **Posted:** Thu Feb 29, 2024 6:29 pm

This is an interesting view in to the operation of the Sabres sleeve valves.
It has similar displacement to the Griffon, but runs at a higher RPM.
That, along with the incredible volumetric efficiency of the sleeve valves are what enable it to make so much more power.

https://www.youtube.com/watch?v=e7gW_sBrqxo

dhfan · **Posted:** Thu Feb 29, 2024 6:34 pm

bdk wrote:

2,240 for the Griffon as well. A lot of power for the displacement. I'd sure like to look inside one.

If you ever get a chance to visit Duxford, there's a sectioned one on display. It's mind-boggling.

I read some time ago that they got 5000hp out of an experimental engine, but I suspect not for very long.

Dan Jones · **Posted:** Thu Feb 29, 2024 10:10 pm

Dave Hadfield wrote:

Our record with UK restorations of rare engines has been mixed.

Bristol Pegasus for our Swordfish? Total incompetence by Deltair, UK. Worthless. Example: they re-installed rusty ancient valve-springs. Took 4 years and cost a fortune. We sold the aeroplane rather than do it again.

Bristol Mercury for our Lysander? Excellent. Handled by the people at Duxford. I flew it on a 2000 mile trip to OSH in 2022 and during the following Annual the cylinder pressures were all high-70s.

R-R Kestrel for our Fury? The jury is still out -- it hasn't been run at high power yet (the overhauler refused to do it). It too cost a fortune (3x the original rough-guess). But I'm hoping for competence, since I'll fly it next year.

Dave

Fury? I missed this.

helinut · **Joined:** Tue May 25, 2004 11:57 am **Posts:** 166

Dan ,I believe they Fury they acquired is the scratch built replic that was started by the late George Neil, who restored the Hawker Hind at the natiobal museum

Dan Jones · **Posted:** Fri Mar 01, 2024 12:57 am

Yes - thank you - I did a little digging and saw some pics. Mr Neil was quite the craftsman!

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11282

dhfan wrote:

If you ever get a chance to visit Duxford, there's a sectioned one on display. It's mind-boggling.

I read some time ago that they got 5000hp out of an experimental engine, but I suspect not for very long.

Seen the sectioned one in the UK.

If you get a chance search up the Napier Nomad. Even more complex than the Sabre. Combined an axial flow turbocharger with a turbo-compound arrangement and it was a diesel. Brilliant, if not for jets!

<Edit> Fixed a typo!

Warbird Information Exchange

Kermit Weeks Tempest MkV

Who is online