It's like 2 engines in 1!
In case you haven’t noticed, we like bizarre powerplants on this blog. We’ve discovered nuclear-powered jets and missiles. This morning we saw (and heard!) a two-stroke, 6 piston, 3 cylinder horizontally opposed diesel engine that has made more than one head explode. Well, Black Steelies reminded me of a bizzare powerplant that just might make your head implode back to normal…behold, the diesel/turbine Napier Nomad!
In 1945, the UK government looked across The Pond and saw those wacky Americans at the Curtiss-Wright factory working on a combination gas and turbine engine. The Brits, in their haughtiness, thought they could do better. And they almost did.
The Air Ministry wanted an engine rated at 6,000 hp and with good fuel economy. Sir Harry Ricardo suggested that a diesel engine would meet this objective. British engine builder Napier already had some experience with diesel aircraft powerplants. Prior to WW2, Napier had licensed the Junkers Jumo 204 design and called it the Napier Culverin. With the onset of the war, though, Napier & Son focused on its Saber engine. When they heard the boys at Adestral House were discussing a high horsepower, efficient engine they jumped at the chance.
Napier origianlly started off by putting two Culverins together in an H-block formation. This resulted in a 75-liter engine…a bit bigger than anything could handle. So, they reverted to what they learned from ze Germans and applied it in a race against the ‘Mericans. The result was the horizontally-opposed 12 cylinder Nomad. It bested the Curtis-Wright design, and was competitive with the early jet engines. But, it had issues.
Napier’s idea was to use the high thermal efficiency of a piston engine, the fuel efficiency of a diesel engine, and the power of a turbine engine. The concept was to replace the combustion chamber of the turbine engine with the diesel engine. However, they had problems coupling the diesel engine back into the turbine. By the time they started making progress on figuring out these problems, jet engines had advanced and the Boeing 707 was on its way with 4 shiny new jet engines ready for service.
Two Nomads were designed. The first, called Nomad I, was intended to drive contra-rotating props. It was essentially two engines in one, with a turbo-supercharged diesel engine driving one prop, and a complete Napier Naiad turboshaft engine below it driving another prop AND the compressor for the supercharger. It would also have a sort of afterburner capability with additional fuel being dumped into the turbine during takeoff. So, it was a supercharged diesel with a turboshaft and an afterburner. The Nomad I was tested in the nose of an Avro Lincoln bomber and, when operating properly, provided 3,000 hp with a very good specific fuel consumption.
Even before Nomad I was complete, Napier began work on Nomad II. In the Nomad II configuration the engine was greatly simplified. An additional compressor stage was added to the turboshaft engine to act as a turbocharger on the diesel engine with the diesel exhaust gases driving the turbine. Rather than two separate engines, the system behaved more like a diesel engine with a big ass turbo-supercharger…which also provided some thrust. One set of props was removed and the engines now were coupled via a hydraulic clutch. This configuration resulted in an engine that was half a ton lighter and produced about 3,100 hp. It was tested in an Avro Shackleton.
A third variant was in the works when the Ministry of Defence decided to cancel the Avro Shackleton IV, the only planned aircraft to use the Nomad III. This bizarre engine breathed its last breath in 1955 after over 5 million pounds sterling were spent on its development.
[Photo Credits: Public Domain via Wikimedia Commons]
Holy crap, I was just reading up on this thing after I wandered back over to the "ten craziest engines" article. Thanks for doing the writeup, I was reading through it and it was making my brain all hurty.
Imagine trying to understand it enough to write semi-intelligently about it. My brain still hurts…
Also, I'm noticing a trend with the bizarre engines. So far, Britain is 2 for 2.
So who's up for the BRM H-16?
Don't they get points taken away for essentially enabling the development of the Mig 15 & 17 by providing Rolls Royce Nene engines post-war? I may have confused my facts there…
That is true. Mikoyan and Yakovlev both went to Stalin and suggested they get engine technology from the west since their own technology was based on a German jet design from the war and new aircraft were outpacing any improvements the Soviets could make to that engine. Stalin reportedly responded, "What fool would sell us his secrets?"
Mikoyan and his engine designer traveled to Britain where they did exactly that.
There's a stall at Portobello Road Market. Ask for Cecil, he's doing a special. Buy blueprints for the Nene and you get the Goblin thrown in. £45 to you, mate.
You did good. It was totally worth your brain hurting to enlighten me.
Christ it's tough to top the Deltic from yesterday but this really does it. Good call engineerd!
OK, after some fervent googling I may have found a 'merican ICE worthy to compete with the oddball Brits. The OX2 engine was developed recently by some private firm in LA.
I can't find too much info as to how it works but it has 8 cylinders arranged radially that must fire in some sequence as to articulate the piston plate and push the cam/drive plate in a rotational motion. Way cool stuff, check out the site.
<img src="http://www.ox2engine.com/images/Engine_Explosion_sm.jpg">
I seem to remember reading about a post-war engine project combining a piston engine with a turbo-supercharger, in which the development team found they could extract more power from the turbo than from the piston engine itself, at which point they went ahead with a turbine engine. I can't for the life of me remember where I read this or even if it's true. Aargh!
I think you're right. If my rusty memory is any good it was the Pratt turbo compound R3350. They actually went into service on some aircraft. I think the RCAF Argus maritime patrol aircraft was fitted with them. Unfortunately they blowed up real good.
XF-12 Rainbow is the project. it used something like 2 power recovery turbines and 2 turbos per engine (4 engines) at high (44k feet) altitude.
I AM NOMAD…
<img src="http://vulcanstev.files.wordpress.com/2010/06/insp_nomad.png" width="400">
Imperfect!
Non sequitur. Your facts are uncoordinated…
It's a long tradition, and something we're very good at. We will plough enormous piles of money into research for something, and then pick either of the following plans:
A) Cancel the project citing lack of worthwhile applications for the end product,
B) Complete the project and then give the rights to it away for virtually no money,
C) Complete the project and then find that the initial problem could have been solved with far simpler technology.
Example for A) The TSR2 Reconnaisance plane was developed at massive expense, but was cancelled at the eleventh hour and the RAF bought F111s instead. (My second favourite aircraft of all time, but that's besides the point)
Example for B) The USAF, The Russians, The Japanese, everyone benefitted from Mr Whittles hard work, thanks to our Air Ministrys philanthropic tendencies
Example for C) The prop driven Bristol Brabazon and the Saunders Roe Princess, intended for long distance passenger travel were total blind alleys with the Jet Engine (which had already been developed) already primed for use in the 707 and Comet.
It's 11:32 and I already need a drink.
"Napier’s idea was to use the high thermal efficiency of a piston engine, the fuel efficiency of a diesel engine, and the power of a turbine engine."
Good idea's should sound more like this.
Petlyakov Pe-8 used diesel engines. =)
[...] Contra-rotating propellers tend to use a planetary gearbox. However, the first Napier Nomad used a diesel engine for one direction and a turbine for the other, and the GE UDF used extremely sexy interlaced turbine stages which themselves rotated in opposite [...]