Twin props one engine

[Arthur Brown]

Searching ebay for "austin diesel" brought up lots of interesting engine manuals. Maybe one would help?

[MtB]

 

 

 

 

The Sopwith Camel was fitted with a rotary engine. These caused very large torque effects because the whole engine rotated which caused massive gyroscopic effects. That is why they turned very well in one direction and very poorly in the opposite direction!

 

Isn't that a 'radial' engine rather than a 'rotary' engine?

 

Mike

[bizzard]

Isn't that a 'radial' engine rather than a 'rotary' engine?

 

Mike

No,a radial engine is mounted normally with the propeller fixed to the crankshaft.

A Rotary engine has the prop fixed to the engine mass and rotates with it whilst the back of the crankshaft is bolted to the airframe ''held static''while the engine mass and prop all whirl around ''it''.

Edited April 25, 2012 by bizzard

[Teadaemon]

I agree with those who suggest that the easiest way to get both props turning will be to get the other engine running (or replace it with a similar one that does run).

 

To run two props off one engine then a hydraulic or electric drive train would be the sensible answer, as having two props that can't be controlled independently vastly reduces their usefulness. Chain or belt drive from one propshaft to the other introduces a load of extra complexity into the system for not a lot of reward, and may well reduce performance or overload the engine (as the props are sized to work with the power of one engine, but the available power would be significantly less than 50% of this to each of them).

 

Edited to add:

 

Going off-topic, the Sopwith Camel definitely had a rotary engine, which works as described above (and was also lubricated with castor oil, ensuring that amongst the other things WWI pilots had to deal with, they were also extremely regular).

 

The Fairey Gannet actually had an Armstrong-Siddeley Double Mamba - two turboprop engines mounted side by side and driving contra-rotating propellors. IIRC, both engines were used for takeoff and landing, or when required for operational purposes, but for cruising only one was used (changing over every hour to even out wear).

 

All Avro Shackletons had Rolls-Royce Griffon engines driving 13' diameter contra-rotating propellors.

Edited April 25, 2012 by Teadaemon

[Deano]

Engines in twin engine installations normally turn in the same direction, (apart from bigger ships engines) and the propshafts turning in opposite directions is done through the gearboxes.

 

I've been on a few boats with twin engine installations where engines, gearboxes and props all turned in the same direction, and so they had 2 right-, or 2 left handed props, and even with a set-up like that, they handled well.

 

Peter.

 

That is my experience too.

 

Older boats often have everything going the same way as reversing gearboxes were not commonly available. Mine is 1966, a twin diesel setup where everything rotates the same way and I have two identical props. High power reversing gearboxes (where the output turns the opposite way to the input when in forwards drive) were simply not available at that time.

 

The prop walk is noticeable but not a problem... you get to learn to use it to your advantage.

 

Deano

[ditchcrawler]

 

All Avro Shackletons had Rolls-Royce Griffon engines driving 13' diameter contra-rotating propellors.

and I thought Victoria had a large prop

[Timleech]

That is my experience too.

 

Older boats often have everything going the same way as reversing gearboxes were not commonly available. Mine is 1966, a twin diesel setup where everything rotates the same way and I have two identical props. High power reversing gearboxes (where the output turns the opposite way to the input when in forwards drive) were simply not available at that time.

 

 

 

Deano

 

There's probably some truth in what you say, though there were ways of doing it via the reducing gears. Some (eg Self-Changing Gears) used a reduction box with an internal gear and some (eg Parsons) used a 3-wheel reduction.

'Proper' marine engine makers offered handed pairs of engines, where the engines themselves ran in opposite directions.

 

Tim

Edited April 26, 2012 by Timleech

[jelunga]

I agree with those who suggest that the easiest way to get both props turning will be to get the other engine running (or replace it with a similar one that does run).

 

To run two props off one engine then a hydraulic or electric drive train would be the sensible answer, as having two props that can't be controlled independently vastly reduces their usefulness. Chain or belt drive from one propshaft to the other introduces a load of extra complexity into the system for not a lot of reward, and may well reduce performance or overload the engine (as the props are sized to work with the power of one engine, but the available power would be significantly less than 50% of this to each of them).

 

Edited to add:

 

Going off-topic, the Sopwith Camel definitely had a rotary engine, which works as described above (and was also lubricated with castor oil, ensuring that amongst the other things WWI pilots had to deal with, they were also extremely regular).

 

The Fairey Gannet actually had an Armstrong-Siddeley Double Mamba - two turboprop engines mounted side by side and driving contra-rotating propellors. IIRC, both engines were used for takeoff and landing, or when required for operational purposes, but for cruising only one was used (changing over every hour to even out wear).

 

All Avro Shackletons had Rolls-Royce Griffon engines driving 13' diameter contra-rotating propellors.

Apart from the early Shacks that had Merlins

[Triumphtone]

No,a radial engine is mounted normally with the propeller fixed to the crankshaft.

A Rotary engine has the prop fixed to the engine mass and rotates with it whilst the back of the crankshaft is bolted to the airframe ''held static''while the engine mass and prop all whirl around ''it''.

 

 

Rotary engine shown here; http://www.animatedengines.com/gnome.html

 

Anth

Edited April 26, 2012 by Triumphtone

[bizzard]

Rotary engine shown here; http://www.animatedengines.com/gnome.html

 

Anth

Thanks for that Triumhtone. Quite a high tech arrangement for the time.

 

Lots of other air cooled radial engines like the Bristol range,the 9 cyl Bristol Pegasus for example and Pratt & whitney ect were also a work of art with multiple use of 2 row con-rod and crank journals. The motions are Spyrograph like.

[RLWP]

Thanks for that Triumhtone. Quite a high tech arrangement for the time.

 

<snip>

 

Well, an automatic inlet valve and one cam for all the exhaust valves does make things a bit simpler

 

Richard

[RobinJ]

Yes, I agree in it's original incarnation it must have been lovely to manoeuvre on the twin throttles. I haven't done any assessment of the non-working engine yet. Minimum is a full set of injectors. I assume it's a BMC-alike 1.5.

 

but on the muddy ditch and adjacent rivers, equal power to both props and a rudder should be adequate.

 

As a matter of interest, where would I go about sourcing a set of injectors?

I would think connecting up both props to a single BMC would probably put too much load on it anyway!

You could probably get a new engine and gearbox for the price of fitting a hydralic tank, piping, pump and one or two motors, unless you know a source?

BMC parts are normally easy to get from the various motor factors/Sherpa agents, but there is also places like ASAP, Calcutt and a few more further south! If you try and do it locally, you may have to take a good one of the other engine to make sure!

[Chris Pink]

Ignore the badging. If they are both diesel with the injector pump stuck out the side like a distributor they are BMC 1.5s. Probably means one got pulled from an Austin vehicle. However could just as well be a 2.x if the injector pumps are parallel with the body. If this is a large sea boat they could even be one of the 3.x engines.

 

Having one marked Austin could indicate it is old and if so two things to watch out for. Engine water pumps (if not direct raw water cooled) have had a few variations and I understand some are getting very difficult to source. Very early 1.5s had a two mounting bolt starter and I understand these are now unobtainable. Unfortunately fitting a modern starter involves a new backplate and possibly flywheel housing so please take care before spending cash on rebuilding, make sure of what you have - pics?

 

I would be interested in a description of the gearboxes and how many "engine feet" there are because we may be able to give you more information. At this time I suspect you have BMC B type gearboxes with the reverse shaft rotation handled by an idler in one of the reduction boxes bolted to the shaft end of the main gearbox, but we will see.

 

OK, I have now looked closely. They have a manual with them dated 1979, BMC 1500L (I don't know whether it's the right one). The Austin engine has A19 L5 stamped on the crankcase (engine or block number?)

 

They have a round injector pump stuck out the side. I haven't seen the starter motor third bolt but there's two at 90° so I assume a 3rd underneath

 

It's raw water cooled, has two water pumps, one on the block looking rather BMCish, the other below, I don't recognise, looks more marine.

 

Picture of the gearbox below - hopefully there's enough of it to identify. I don't have the manual for this bit (even though the cover picture shows a gearbox).

 

I am looking for a set of injectors for this (ASAP don't stock them, are there any alternatives to asking Calcutt?)

 

There's also a picture of the injector pump - because that's Art that is. And cats should be banned from boats.

 

Engine

Art

Gearbox

second water pump

Edited May 7, 2012 by Chris Pink

[cereal tiller]

OK, I have now looked closely. They have a manual with them dated 1979, BMC 1500L (I don't know whether it's the right one). The Austin engine has A19 L5 stamped on the crankcase (engine or block number?)

 

They have a round injector pump stuck out the side. I haven't seen the starter motor third bolt but there's two at 90° so I assume a 3rd underneath

 

It's raw water cooled, has two water pumps, one on the block looking rather BMCish, the other below, I don't recognise, looks more marine.

 

Picture of the gearbox below - hopefully there's enough of it to identify. I don't have the manual for this bit (even though the cover picture shows a gearbox).

 

I am looking for a set of injectors for this (ASAP don't stock them, are there any alternatives to asking Calcutt?)

 

There's also a picture of the injector pump - because that's Art that is. And cats should be banned from boats.

 

 

The austin rocker cover could have come from any BMC B series engine,diesel or petrol,it is unlikely to be original.

 

CHERTSEY MEADS MARINE keep a large stock of BMC bits,have a look on their website.

ETA just seen the pics,the raw water pump suggests it is a WORTHAM BLAKE conversion.

Edited May 7, 2012 by cereal tiller

[RLWP]

It's a PRM gearbox. I've got one in bits in the garage at the moment and I recognise the cover plate, breather and filler plug. Don't know which one

 

Maybe a 260? Certainly one with a vertical valve mechanism - I'll get me manual

 

Richard

Edited May 7, 2012 by RLWP

[Chris Pink]

The 260 can be reversed, no?

 

(If I was paying attention to another thread)

 

it should look like this?!!!!!!!!!!!!!!!!

[cereal tiller]

It's a PRM gearbox. I've got one in bits in the garage at the moment and I recognise the cover plate, breather and filler plug. Don't know which one

 

Maybe a 260? Certainly one with a vertical valve mechanism - I'll get me manual

 

Richard

Could be,i thought it was the older 160

[RLWP]

Could be,i thought it was the older 160

 

The 160 has a horizontal vale block, It's a 160 I have apart just now. Could be a 140

 

Chris, the boxes have different internals, and in particular the oil pump is 'on the other side'. So, from the back, one will have the oil pump on the left, the other on the right. The castings are drilled differently for this

 

Richard

 

MORE: Sorry, I'm talking crap. The input shaft is 'on the other side' and the box sits at a different angle

 

The 260 above is a standard, right hand box:

 

 

A left hand box would have the shaft going through the big blanking plug to the right of the input shaft.

 

You should be able to tell if you have a left and a right hand box as they lean in different directions, with the filler plug on the other side

 

Richard

Edited May 7, 2012 by RLWP

[cereal tiller]

The 160 has a horizontal vale block, It's a 160 I have apart just now. Could be a 140

 

Chris, the boxes have different internals, and in particular the oil pump is 'on the other side'. So, from the back, one will have the oil pump on the left, the other on the right. The castings are drilled differently for this

 

Richard

 

MORE: Sorry, I'm talking crap. The input shaft is 'on the other side' and the box sits at a different angle

 

The 260 above is a standard, right hand box:

 

 

A left hand box would have the shaft going through the big blanking plug to the right of the input shaft.

 

You should be able to tell if you have a left and a right hand box as they lean in different directions, with the filler plug on the other side

 

Richard

Was the PRM 140 the road roller reversing gear? i am not quite old enough to remember it.

[RLWP]

Was the PRM 140 the road roller reversing gear? i am not quite old enough to remember it.

 

No idea, it's the other half of my PRM140/PRM265 manual

 

Richard

 

MORE: Top view of a PRM 160 box:

 

 

Notice the label, which will reveal the type of box

 

Richard

Edited May 7, 2012 by RLWP

[Timleech]

The 160 has a horizontal vale block, It's a 160 I have apart just now. Could be a 140

 

Chris, the boxes have different internals, and in particular the oil pump is 'on the other side'. So, from the back, one will have the oil pump on the left, the other on the right. The castings are drilled differently for this

 

Richard

 

MORE: Sorry, I'm talking crap. The input shaft is 'on the other side' and the box sits at a different angle

 

The 260 above is a standard, right hand box:

 

 

A left hand box would have the shaft going through the big blanking plug to the right of the input shaft.

 

You should be able to tell if you have a left and a right hand box as they lean in different directions, with the filler plug on the other side

 

Richard

 

Are you absolutely sure about that, Richard? The usual thing with the 'proper' PRM hydraulic boxes that I know of is just to turn the oil pump around for opposite input rotation and they will work with either rotation of output for 'ahead'.

 

Tim

[RLWP]

Are you absolutely sure about that, Richard? The usual thing with the 'proper' PRM hydraulic boxes that I know of is just to turn the oil pump around for opposite input rotation and they will work with either rotation of output for 'ahead'.

 

Tim

 

Certain.

 

 

This is the back of a 160.

 

I wonder Tim, are you talking about fitting the box to an engine going the other way around?

 

Richard

[Timleech]

Certain.

 

 

This is the back of a 160.

 

I wonder Tim, are you talking about fitting the box to an engine going the other way around?

 

Richard

 

Well, both.

Maybe it wasn't true for the older boxes, but I'm (or was until now!)sure the 160 onwards can have reversed input by swapping the pump round, and reversed output simply by moving the lever the other way. It's certainly true for the 302, a fairly old box for which I have the manual in front of me.

 

Tim

[RLWP]

 

Richard

 

Well, both.

Maybe it wasn't true for the older boxes, but I'm (or was until now!)sure the 160 onwards can have reversed input by swapping the pump round, and reversed output simply by moving the lever the other way. It's certainly true for the 302, a fairly old box for which I have the manual in front of me.

 

Tim

 

You are making my head hurt...

 

The pump is a gear pump. If you turn it over, it will try to flow the other way. So, to correct that, you would have to run the input shaft the other way round.

 

Right, got it. You can set the gearbox up for either direction of input by turning the pump over

 

Richard

[RLWP]

MORE:

 

I think I can see where this is going.

 

You can set the box up for either direction of input by turning the pump over. You can get either direction of output by pushing the control lever backwards or forwards. For a canal boat - job done

 

So, why have a left hand and a right hand box?

 

Well, for a standard box, there are two other things. The first is a reliability issue. In forward, the standard box takes the drive from the input shaft, through the input shaft clutch, and out through the output shaft. If you reverse it by inverting the pump, the drive goes through the input shaft, the layshaft, the layshaft clutch and the output shaft. The is one more set of shafts and bearings involved

 

The second is the 'get you home' feature. Some boxes have a fork in the top cover that can be used to lock the box in forward gear in the event of a hydraulic failure. This only works on the input shaft.

 

These features don't matter on a canal boat, but could matter a great deal out at sea - hence a left hand and a right hand box

 

Richard