mercury engines used in bolingbroke and lysander… engine origin ….?

Actually not anymore it isn’t…that was the original intention but the project has now switched back to Mercury engines. Apparently R1535s in restorable shape are very rare, and since CWH is already operating one Mercury-powered aircraft, Lizzie C-GCWL, it made more sense to go with Mercs. (119 BR Sqn RCAF, the Hamilton Tigers, operated both the standard IVs and most if not all of the small batch of IVWs with Eastern Air Command, so the livery of the completed Boly will be the same, only the serial number being changed. The Boly is coming along very nicely at CWH, just a few miles from here.)

S.

Thanks for the update Steve. Good to hear that they are making good progress, I’m really looking forward to this. It will be well worth the trip from Ottawa to see it fly.
I would ask you when you think it will fly, but about 100 members of this forum will jump all over me for my insensitivity — so I won’t!
Regards
Bill

The Twin Wasp Junior was used in the UK as an alternative to the Mercury on the Master. More reasonably, as I’d have thought the Blenheim would notice a lack of 150hp.

The Canadians also fitted a Hampden with a pair of Cyclones. More generally speaking, the Cyclone gained a bad reputation in the UK for troubles with the Mohawk, though it seems to have worked happily enough in the Hudson. I gather some of the problems came from recycled ex-civil engines as opposed to new build military-standard ones, but I don’t think I’ve seen the matter fully discussed.

Actually not anymore it isn’t…that was the original intention but the project has now switched back to Mercury engines. Apparently R1535s in restorable shape are very rare, and since CWH is already operating one Mercury-powered aircraft, Lizzie C-GCWL, it made more sense to go with Mercs. (119 BR Sqn RCAF, the Hamilton Tigers, operated both the standard IVs and most if not all of the small batch of IVWs with Eastern Air Command, so the livery of the completed Boly will be the same, only the serial number being changed. The Boly is coming along very nicely at CWH, just a few miles from here.)

S.

[I don’t think the Lizzie was equipped with the Twin Wasp Junior, only the Boly. The alternative engine (Lysander) in the UK was the Perseus.
Interestingly the CWH Bolingbroke long-term restoration to airworthy is planned to be powered by TWJ’s.
Regards
Bill

Ah, Twin Wasp Junior – there’s the difference. There’s around 300 cu/in difference between the Twin Wasp Junior (1535 cu/in) and the Twin Wasp (1830 cu/in).

Twin Wasp Junior went from around 600hp to 825hp, comparable with the Mercury in output and, even though Mercury had only nine cylinders its swept volume was only 15 cu/in different (at 1520 cu/in) from the TWJ’s 14 smaller cylinders. So, a pretty even match power-wise.

The R-1820 Cyclone was a large diameter engine and single row so the single Bolly Mk.IV C (presumably meaning Cyclone?) built was, presumably, a one-off experiment. The Cyclone was 3 ins larger diameter so wouldn’t have looked overly larger and with power output the same as the Mercury.

Presumably TWJ for the Lysander too?

Anon.

Hi
a bit of googling has got me
825 hp (615 kW) Pratt & Whitney SB4G Twin Wasp Junior radial piston engines, 15 bolingbroke MK IV W built
900 hp (671 kW) Wright R-1820 Cyclone engines , one MK IV C built
cheers
Jerry

It’s likely that it was the P&W Wasp engine that was planned as a substitute for the Mercury, being of similar size and output as well as a single-row layout. The Twin Wasp would have been rather big for both the Bolingbroke and Lysander.

Anon.

Hi Bill,
Thanks for the reply and info.

‘whiffing’ … I now wonder what a twin wasp lysander could have looked like.
cheers
Jerry

[QUOTE=brewerjerry;2026336]Hi All,
The Mercurys for the Bolingbroke and Canadian Lysanders were all imported from the UK. It was thought that the Mercury engine supply from across the pond might dry up at some point so some Bolingbrokes were built with P & W Twin wasps, but only in small numbers.
Regards
Bill