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SimonBrown

8 Cylinder Torpedo Engine - Restoration

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Not strictly a vehicle, or even a vehicle part...but in absence of anywhere else I thought I would share the latest acquisition on HMVF - it may be of interest perhaps?

Thanks to the generosity of a very good friend, I have acquired a vintage 8 cylinder radial engine that would have originally powered a torpedo. Its pretty much complete but a little scruffy.

As just about every other British origin torpedo motor is a four cylinder radial arrangement, this eight cylinder version is - I suspect - a bit of a rare beast. It is most likely an experimental model and quite possibly originating from the Whitehead Torpedo factory in Weymouth. 

But as of now, its history and origins are unknown. One thing apparent is the the threads look like UNF and the nuts are nyloc variants, so the first obvious question is when was the nyloc nut invented? That would help with a date range, if nothing else.

Will update the thread as restoration gets underway, but like most projects it won't be rushed. The intention is to make it a runner (heaven knows what fuel!) and possibly fit it into a Suzuki GS750 rolling chassis that might be available at some point.

SBrown-20181222-0005.jpg

SBrown-20181222-0013.jpg

Edited by SimonBrown
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Simon,

 

It is military and mechanical, that is plenty good enough for me to have you shows us here on HMVF what you are playing with, don't be shy about it, diversity is the beauty of this forum.

What a glorious and obscure contraption, I have visions of you getting it running and using it to power a small boat, along the lines of "from swords to poughshares"

Keep it coming

 

 

 

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10 minutes ago, Citroman said:

Didn't torpedos run  on compressed air? Later ones were electric i think.

Yes, compressed air, burner cycle with or without enriched O2,, HTP (High Test Peroxide) and electric are all examples of fuel used.

I did have an electric Mk44 air dropped torpedo for a while and connected the motor up to a car battery to see if it was still viable. The contra rotating props worked a treat. But the missus drew the line at an intact, complete and functioning (less the warhead and original battery) torpedo in the garage, so it was donated to the local Sea Cadets who thought all their Christmas and birthdays had arrived at once, so it went to a good home.

Edited by SimonBrown
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nyloc's where used in dingo's so before 1940

Edited by monty2

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16 minutes ago, monty2 said:

nyloc's where used in dingo's so before 1940

Not correct, the Nyloc nuts were intoduced later in the UK. Those on the Daimlers were fibre locknuts or aero nuts.

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I assume it is for a 21" torpedo.....

Bit surprised that it has 8 cylinders, I thought that most radial engines had an odd number of cylinders to give a good balance.

Cheers

Richard

 

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A very interesting engine.  I wonder who made it?   I had some dealings with Commonwealth service torpedoes pre 1990, but have never seen an 8 cylinder engine like Simon's. If it was made in the UK, I would be reasonably certain that it was not produced in any quantity.  Another angle is that it may have been an example of a continental engine (1900-45?) recovered for tech intel purposes?  Re nyloc nuts, can you discount that someone has not had a go at restoring it more recently?

The engine sold by Prestons is a 4 cylinder radial Brotherhood burner cycle engine that went into service in the 21 inch Mk.8 (submarine) and Mk.9 (surface launched) torpedoes. The Prestons one in particular looks like a WW2 produced type that would have been in service until the late 1980s.  Recently I had the job of sectioning a whole Mk.8 torpedo for a museum and read the manual that came with it.  Some interesting specs: (1). The fuel is listed as "shale oil".(2) It carries about 250 pounds of compressed air at 3000 psi (3) Due to this air pressure and volume, the throttling effect would tend to ice up everything (like  how a spray can goes cold when you hold the nozzle down for a long time). (4) They get around this by admitting a small quantity of burning fuel to the air to heat it up before it reaches the engine. (5) The preheated air and cylinder injected fuel then operates as a diesel exhausting into the crankcase and out the propeller shaft. (6) The pre-burn is started by three blank cartridges that are fired on launch. (7) If the ignition fails, the torpedo can still do about 22 knots just on air pressure for a few hundred yards.  When the navy tested the engines on a dynomometer, they would routinely produce about 550 horsepower.  Not bad for a tiny radial engine designed in 1926.  All that said, the salient point is that you need about 3000 psi air boost to get that performance, so not especially convenient for a motorbike, etc.

My reference to tech intel is base on a discovery made in Sydney a couple of years ago.  In the mangrove swamps near an ex-ordnance depot, a large complex bronze casting was pulled out of the mud.  No one had any idea what it was, but it was kept due to being old and mysterious.  It turns out to be a Whitehead designed long stroke 2 cylinder engine from a Japanese submarine torpedo.  This was a 21 inch type, but the fabled "Long Lance" Type 93 24 inch torpedo used the same design.

BTW, while torpedo engines may seem a bit niche, torpedo gyros have been keenly collected for many years.  They are amazing bits of precision kit and span about 120 years - from clockwork, compressed air to electrical methods of spinning them up.  The Mk.8 torpedo uses a quick blast of the 3000  psi air supply to bring the rotor from standstill to about 30,000 rpm in a fraction of a second. 

Japanese Torpedo engine.jpg

Mk.8 Mod4 1.JPG

Mk.8 Mod4 2.JPG

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amazing that this almost forgotten engine technology has been around for over a hundred years and never been developed. Think of the bhp potential from such a compact engine! 

Incredible to think something  this advanced is built a a single use engine, made to last just a few seconds!

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1 hour ago, terryb said:

Incredible to think something  this advanced is built a a single use engine, made to last just a few seconds!

Yes, in a few minutes it was over. Amazing level of engineering for such a short time.

We do know very torpedo built at Whiteheads was fired at least 4 times before being shipped to the customer,  just to make sure it would function as intended. We have found a few in Weymouth Bay that went missing. All of them had lead segments replicating the weight of the warhead. 

Quote

Rijeka had a prototype 8 cylinder torpedo motor back in 1902:

That one is a real gem, and so far the only other 8-cylinder example I can find.

Quote

If it was made in the UK, I would be reasonably certain that it was not produced in any quantity.  Another angle is that it may have been an example of a continental engine (1900-45?) recovered for tech intel purposes?  Re nyloc nuts, can you discount that someone has not had a go at restoring it more recently?

Because of where it came from (Weymouth) we are pretty sure it came from the Whitehead Torpedo Works at Wyke. Whitehead were taken over by Vickers Armstrong and as far as I can tell work on an 8-cylinder engine started in 1938 and continued after the war. So current thinking is UK/experimental/test & development unit. I had not considered a captured/foreign unit, and is possible. 

Nor had I considered the nylocs being a recent(ash) edition. Some of the studs are not long enough to fully engage with the nylon insert, so thats a possibility too.

There are a few documents to look up in the National Archives, so a trip is planned soon.

And thanks for a clear and simple description of how and why it works the way it does Watercart - that was a big help in understanding some features I was scratching my head at. Nice find with the Japanese motor too - glad its been saved.

Edited by SimonBrown
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15 hours ago, 64EK26 said:

Bit surprised that it has 8 cylinders, I thought that most radial engines had an odd number of cylinders to give a good balance.

Yes, this point had been bugging me too. Turns out there is a good reason. 4-stroke radials have an odd number to keep an every-other-piston firing order for smooth running. 

The 4 and 8 cylinder torpedo motors in this thread are 2-stroke diesel engines and have twice the number of power strokes per crankshaft revolution when compared to their 4-stroke cousins.

More here at Wikipedia.

Personally, I think an open pipe 8 cylinder 2-stroke compression ignition engine is going to sound awesome on full chat. The neighbours might not agree mind.

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21 hours ago, SimonBrown said:

Will update the thread as restoration gets underway, but like most projects it won't be rushed. The intention is to make it a runner (heaven knows what fuel!) and possibly fit it into a Suzuki GS750 rolling chassis that might be available at some point.

 

 

I don't think the engine would be suitable for a motorcycle or any other vehicle as the engine speed cannot be regulated, unless the fueling was re-engineered.

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1 hour ago, SimonBrown said:

Yes, this point had been bugging me too. Turns out there is a good reason. 4-stroke radials have an odd number to keep an every-other-piston firing order for smooth running. 

The 4 and 8 cylinder torpedo motors in this thread are 2-stroke diesel engines and have twice the number of power strokes per crankshaft revolution when compared to their 4-stroke cousins.

More here at Wikipedia.

Personally, I think an open pipe 8 cylinder 2-stroke compression ignition engine is going to sound awesome on full chat. The neighbours might not agree mind.

like car and bike boxer opposed cylinder engines, a 4 or 8 cylinder radial 2 stroke will give a huge amount of torque, as it will fire opposed cylinders simultaneously and being 8 cylinder will be an almost continuous power stroke! 

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3 hours ago, Richard Farrant said:

I don't think the engine would be suitable for a motorcycle

Agreed, but the concept is so insane it is begging to be done. 

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21 minutes ago, SimonBrown said:

Agreed, but the concept is so insane it is begging to be done. 

One for Allen Millyard?

2 of his bikes:-

 

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I seem to recall reading somewhere that 8 cylinder radial engine’s where used in torpedo’s and midget submarines??

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16 hours ago, MatchFuzee said:

One for Allen Millyard?

Kind of, but in a far less practical way I think.

 

11 hours ago, Nrhampton said:

I seem to recall reading somewhere that 8 cylinder radial engine’s where used in torpedo’s and midget submarines??

4 cylinder Gardner in the X Craft I think.

From what I have found out so far the 8-cylinder was a development to make the torpedo run faster - around 50 knots or so. Which for an underwater weapon is quite a feat. Designed for short burst of high speed and then bang, rather than long endurance.

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As it is a two stroke radial, the only way it would run is to have a supercharger to compress the intake air, then there is a variable fuel supply required so engine speed can be regulated if you were to plan on using it in a motorcycle or some other vehicle. There there is the cooling aspect, I think the torpedo engine was cooled by the sea water as they were not designed for long running.

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11 minutes ago, Richard Farrant said:

As it is a two stroke radial, the only way it would run is to have a supercharger to compress the intake air, then there is a variable fuel supply required so engine speed can be regulated if you were to plan on using it in a motorcycle or some other vehicle. There there is the cooling aspect, I think the torpedo engine was cooled by the sea water as they were not designed for long running.

Its the cooling that is occupying my thoughts and with no apparent resolution at present. Seawater was indeed used, flooding the engine compartment negated the need for any other cooling.

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You could build a clear plastic tube around it to replicate the torpedo  filled with water.

 

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7 hours ago, mogmaner said:

You could build a clear plastic tube around it to replicate the torpedo  filled with water.

 

The potential for creativity unleashed is almost without limits, you could say.

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