Author Topic: Opposed Piston Engine  (Read 3754 times)

Offline joshagrady

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Opposed Piston Engine
« on: November 16, 2015, 06:13:44 AM »
I'm sure that for most of you this will be old news, but for those who, like me, had never heard of this sort of configuration, here are a few images of an engine type I stumbled across this weekend.





https://youtu.be/sWjMBSnq2es

Offline seadog

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Re: Opposed Piston Engine
« Reply #1 on: November 16, 2015, 06:18:10 AM »
The Deltic. Based on a German design I believe.

Offline John Rudd

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Re: Opposed Piston Engine
« Reply #2 on: November 16, 2015, 06:22:28 AM »
and there's an excellent example of this type of engine on display at the National Railway Museum in York...
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Offline sparky961

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Re: Opposed Piston Engine
« Reply #3 on: November 16, 2015, 04:23:25 PM »
Definitely unconventional. But what's the advantage?

...And what do you do with the power from 3 separate crankshafts?

Offline awemawson

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Re: Opposed Piston Engine
« Reply #4 on: November 16, 2015, 04:32:19 PM »
Andrew Mawson
East Sussex

Offline JD

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Re: Opposed Piston Engine
« Reply #5 on: November 16, 2015, 05:24:26 PM »
Germans had the idea of making a smaller version for long range bombers in WWII but didn't have enough time for development, After the war Napier's took over the development, with a lot of R&D and one of the major changes was giving the exhausting piston a lead of 17 deg over its opposing piston (amongst other tweaks) it became the Deltic.
Having spent the last 12 years of a 23 year stint in the RN in the engineering department on Ton Class mine sweepers/hunters Bronnington being one of them. (HMS Bronnington was brought into the lime light when Prince Charles was made the skipper) I joined some 10 years later.
We had 2 18/7a as main engines on both Sweepers and Hunters, free end of the engine was a massive blower driven from the phasing gear case on the drive end, the phasing gear case (as seen in the Bronnington photos) took the drives from all 3 crankshafts through this gear case then a final drive through an hydraulic clutch oil pressure being supplied from the engines own oil supply for ahead and astern manoeuvres, then to the prop shaft. On the Sweepers a 9 cylinder engine was installed for pulse generation in 3 phase for sweeping mines.
All boats where double skin African Mahogany on aluminium frames.
The whole boat had a very low magnetic signature.
A pair of 18/7a flat at 1478 max revs makes a hell of a racket, these engines only worked well flat out. Slower speeds caused small amounts of engine oil to be carried over in the exhaust gasses settling in the base of the funnel. After hours of slow running and towing a quick increase in speed could see the carry over of hot carbon which could cause a funnel fire, I never heard of one taking place, a slow but steady increase in engine/shaft revs would blow all that muck up and out of the funnel, at night this may cause a fire works display akin to a Roman candle. British rail also had the same problem with oil carry over but don't know of their fix. These engines where 2 stroke with 2 injectors per cylinder and started via a large cartridge (as for the old radial engine fixed/rotary wig aircraft).
Fuel consumption was 1 UK gallon a min flat out for each engine.
The engines where also installed in PT boats in the US.
Anybody interested google HMS Bronnington where she lays in a hell of a mess in Liverpool docks in a once caring maritime museum, it breaks my heart  :(

JD

 
 
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Offline sparky961

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Re: Opposed Piston Engine
« Reply #6 on: November 16, 2015, 05:59:05 PM »
Good reading. Thanks all for bringing it back into the light.

Offline vtsteam

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Re: Opposed Piston Engine
« Reply #7 on: November 16, 2015, 09:39:26 PM »
I remember a highly detailed model of one in ME not too long ago -- well maybe 10 yrs.
I love it when a Plan B comes together!
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Online RobWilson

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Re: Opposed Piston Engine
« Reply #8 on: November 17, 2015, 04:37:42 AM »
The Germans did have an opposed piston diesel engine ,The  Junkers Jumo 205


This is one in the German Museum of Technology ,Berlin




A rather interesting engine  :dremel:



Rob




Offline DavidA

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Re: Opposed Piston Engine
« Reply #9 on: November 17, 2015, 06:29:21 AM »
I suppose someone aught to point out that the top picture by Joshagrady isn't quite the same idea as the Deltic. I haven't seen this configuration before.

For a start it only has one crankshaft.

Re: the Deltic design.

...Definitely unconventional. But what's the advantage?...

Definitely much more compact. How else can you get so many pistons in such a short space.  It also simplifies the fuel injection system.

...And what do you do with the power from 3 separate crankshafts?

You use them all to drive one output shaft.

Dave.


Offline BillTodd

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Re: Opposed Piston Engine
« Reply #10 on: November 17, 2015, 08:59:08 AM »
Quote
I suppose someone aught to point out that the top picture by Joshagrady isn't quite the same idea as the Deltic. I haven't seen this configuration before.

More like a tiny Doxford* . Interesting compressor/balance piston but a complicated design for a single cylinder and not best suited for high revs :-(

[edit] *didn't see the youtube link first time 'round.
Bill