"Cé hé sin" (michael-m-mouse)
11/11/2016 at 16:21 • Filed to: Napier, Deltic, Hunt class minesweeper
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"Cé hé sin" (michael-m-mouse)
11/11/2016 at 16:21 • Filed to: Napier, Deltic, Hunt class minesweeper | 10
| 9 |
This is a Napier Deltic engine.
It’s a two stroke opposed piston diesel which works like this, multiplied by three or six:
The Deltic is very smooth running and was chosen for use in minesweepers because it was less likely to set off acoustic mines than more conventional units.
This is HMS Quorn
She’s a Hunt class minesweeper in use by the Royal Navy. She and her sister ships were built in the early 1980s and were the last ships to use the Deltic. Their other claim to fame is the use of fibreglass hulls, also chosen as being less likely to set off mines.
Sadly, the days of the marine Deltic are numbered. HMS Quorn has escaped thus far but four of the eight Hunts remaining in the UK have been upgraded which involves hauling out the Deltics and replacing them with less unusual engines sourced rather surprisingly from Caterpillar, an engine supplier not so often encountered on this side of the Atlantic. Once all of the UK Hunts have been refitted there will still be a couple in service with the Greek navy which so fas I know still proceed with the characteristic buzzing noise of the Deltic.
Want to hear a Deltic? They were also used in trains and some have been preserved.
Like this one:
HammerheadFistpunch
> Cé hé sin
11/11/2016 at 16:26 |
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Deltics are both wonderful and stupid. fun fact, one of the crank shafts runs backwards to the other two.
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Cé hé sin
> HammerheadFistpunch
11/11/2016 at 16:31 |
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Yes, this turned out to be the secret to making them run properly.
Hardly stupid though. They were designed to get as much power as possible into as small a space as possible.
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HammerheadFistpunch
> Cé hé sin
11/11/2016 at 16:32 |
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well, I mean they are amazing and all, but stupid in their complexity and maintenance.
ttyymmnn
> Cé hé sin
11/11/2016 at 16:34 |
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jimz
> HammerheadFistpunch
11/11/2016 at 17:11 |
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they save a lot of complexity by being opposed-piston two-stroke and not needing a valvetrain of any kind.
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HammerheadFistpunch
> jimz
11/11/2016 at 17:16 |
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Does that balance having 3 cranks and a means to connect then to a single output? I don’t know
Manwich - now Keto-Friendly
> Cé hé sin
11/11/2016 at 17:26 |
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Definitely not the cleanest running engines...
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Cé hé sin
> Manwich - now Keto-Friendly
11/11/2016 at 17:46 |
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You should see one starting after a long time stopped....
They tend to collect oil in the exhaust when not running and when started from cold produce enough smoke to rival a steam engine.
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jimz
> HammerheadFistpunch
11/11/2016 at 19:45 |
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Philosophically it depends on how you view “complexity.” You have a good point in that you basically have three piston engine bottom ends bunged together with as many or more moving parts. I was thinking about it in the sense of being “complicated,” with a valvetrain increasing the number of kinds of parts in the engine. In the end, it’s probably somewhat of a wash. The 3 cranks are connected via helical spur gears, which are conceptually simple but still can break and can help eat bearings, etc.
