Author Topic: Bristol Hercules sleeve valve radial engine plans drawings  (Read 5680 times)

Offline Jo

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #30 on: January 24, 2022, 03:54:00 PM »
Jo. Did you ever get to make your G30 engine run?  If so, how did you do that?  I ask as, as well as me, a friend "Down Under" who sent me the plans could not get it to fire either.  He had the benefit of build instructions and castings, I did not have any instructions and built it from bar stock not castings.

Its still in the casting collection  :pinkelephant: I have been told it is a difficult one to get to run  ::)

Jo
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Offline dieselpilot

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #31 on: January 24, 2022, 04:01:01 PM »
The design in the videos Achim posted is based on the Barr & Stroud published in SIC. There seem to be a few working examples of the Barr & Stroud on the web.

People build what they know, and can get information for. I've spent a lot of time looking for information sleeve valve engines. There simply isn't much in the public domain. It's no surprise there aren't many models built. I have prints for the Barr & Stroud and G30.

Other than sealing two rings making a thin sleeve round, what else would be problematic? Which components remain to be made? Do you have sleeve cranks and sleeves? Materials are a concern if there is to be significant power and/or runtime.

Online Vixen

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #32 on: January 24, 2022, 04:17:51 PM »
The design in the videos Achim posted is based on the Barr & Stroud published in SIC. There seem to be a few working examples of the Barr & Stroud on the web.

People build what they know, and can get information for. I've spent a lot of time looking for information sleeve valve engines. There simply isn't much in the public domain. It's no surprise there aren't many models built. I have prints for the Barr & Stroud and G30.

Other than sealing two rings making a thin sleeve round, what else would be problematic? Which components remain to be made? Do you have sleeve cranks and sleeves? Materials are a concern if there is to be significant power and/or runtime.

I also have the Barr and Stroud drawings published in SIC. The port details are not too clear. Oh! I sold you the G30, remember?

Whats still to be made? The crankshaft, drive gears, sleeve cranks and the sleeves and cut the fins on the cylinders.

Cheers

Mike
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Offline AVTUR

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #33 on: January 24, 2022, 04:27:52 PM »
A story from my youth, told to me by a retired very senior stress engine at Bristol who had been a flight test engineer on Herculeses before the War.

An engine designer called Pobjoy had a firm making rather nice, good, small poppet valve radial engines. The company was taken over, not by Bristol Engines, and he went to work for Fedden. Soon afterwards he was head-hunted by a company 35 miles up the A38 from Filton to design, develop and put into production a small auxillary engine for the Air Ministry. His little engine was a sleeve valve. When it first went to test it refused to start. The testers did everything to get it going including calling the idiots who had designed the thing. It would not start. Eventually someone decided to look at the drawings and realised its rotation was in the wrong direction. Everyone went home for the evening except for a junior fitter who had to turn the magneto round. Next morning the engine started immediately and ran for about ten seconds before suddenly stopping with a horrifying screech.

If you have to reverse the running direction of an engine remember the oil pump!

Forty years ago someone used to ride an Barr & Stroud sleeve valve V twin in local vintage motorcycle runs. I remember it as a very sweet running machine.

Enough stories

AVTUR
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Offline lohring

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #34 on: January 24, 2022, 04:28:30 PM »
As was mentioned, the last issue of SIC has a sleeve valve engine build.  Below is the port layout used in most aircraft engines from Sir Harry Ricardo's book The High Speed Internal Combustion Engine.

Lohring Miller


Online Vixen

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #35 on: January 24, 2022, 05:04:13 PM »
As was mentioned, the last issue of SIC has a sleeve valve engine build.  Below is the port layout used in most aircraft engines from Sir Harry Ricardo's book The High Speed Internal Combustion Engine.

Lohring Miller

Hello Lohring,
Which edition of Ricardo's book did that illustration come from? It's not in my edition 5 of the great book

Does your edition of the book tell whether the port timing, in the illustration, relates to a normally aspirated or a supercharged engine?

Mike
« Last Edit: January 24, 2022, 05:14:40 PM by Vixen »
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Online Vixen

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #36 on: January 24, 2022, 06:16:44 PM »
......... Below is the port layout used in most aircraft engines from Sir Harry Ricardo's book The High Speed Internal Combustion Engine.

Lohring Miller

Download and save Lohring's illustration, you can then zoom in and examine it in much finer detail.

Up in the top left, it shows the cylinder and sleeve port sealing area can be as little as 1.915 degrees. 

For a full size cylinder 5.75" diameter that equates to 0.1": Small but manageable. 

However at 1/4 scale the sealing distance becomes a mere 0.025". Far too close for comfort; one false cut with the file during manufacture and there is a leak path between the combustion chamber and the inlet ports.       It may be wise to reduce the size of both the sleeve ports and cylinder ports to give better sealing.   :thinking: :thinking:

Just an observation. Not been there, not done it yet.

Mike 
« Last Edit: January 24, 2022, 06:31:54 PM by Vixen »
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Offline Laurentic

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #37 on: January 24, 2022, 09:03:20 PM »

It is interesting that Ageless engines could not get their 9 cylinder sleeve valve engine to run, but I thought they had got a single cylinder trial version to run......??

Chris.  :shrug:

Lee at Ageless does not understand why his 14 cylinder (not 9) Hercules look-a-like will not run. He did get the single cylinder test rig to run. There is a video of it running on his website. You may have to dig down to find it.

Have you tried a soapy water bubble test, to look for any obvious external air leaks, on your G30

Mike

That is strange.   You would think if a single cylinder version would run a 14 cyl. version would run too.

An air pressure leakage test on the G30 is on the agenda Mike, when I can get back at it.  Unfortunately there are some domestic tasks first and then some shed tasks to follow before I can get to it.

I also have the 5th edition of Ricardo's book, but it does say somewhere in the introduction that a lot of the sleeve valve stuff had been binned, which is a shame; I guess if a copy of an earlier edition came on the market it might be quite sought after.  But thanks for the tip of downloading and zooming in on Lohring's illustration - a good one, interesting.

Jo - as I said earlier, I can testify to the G30 being a trifle difficult to start!  Look forward to reading about your efforts in the fullness of time.   :cheers:

Chris.

PS. Found (on the 'net) a 1960 edition - so 4th edition - for 90 and a 1953 edition, which could be a 3rd or a 4th edition as the 4th. edition came out in 1953,  for 147, so prices as I expected.
« Last Edit: January 24, 2022, 09:34:29 PM by Laurentic »

Online Vixen

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #38 on: January 24, 2022, 10:39:26 PM »
Hello Chris,

In edition 5, Ricardo skips over the Bristol involvement in less than half a page. He uses the book for self promotion ( and for his consultancy company) so perhaps does not wish to diminish his own star with Feddon's achievements. An earlier edition is simply too spendy.

It would be very instructive if you were to blow air into the combustion chamber of your 'no compression Green G30', through the spark plug hole and slowly turn the engine over two complete revolutions. If you were to submerge the entire engine in a fluid, water, paraffin, white spirit etc; you could observe where the air escapes from. With the piston at BDC on the firing stroke the close proximity of the ports could create a leak path from combustion chamber to the inlet ports, just before the exhaust ports open. Similarly, there could be another potential leak; combustion chamber to exhaust port, during the initial part of the compression stroke. Other problems could also be identified by the bubble test.

Much depends on the shape and size of the Green G30 ports. Perhaps you could post here (or PM) a copy of the port drawings.

Cheers

Mike

« Last Edit: January 24, 2022, 11:29:00 PM by Vixen »
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Online Art K

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #39 on: January 25, 2022, 03:18:01 AM »
Sorry to jump in at such a late point in the conversation. The sleeve valve engine is an interest of mine. The Bristol engine is based on the Burt & McCollum design, also used by Argyll. I do have a friend that I usually see at the NAMES engine show who built a running Barr & Stroud single. He cut up his hand with the cooling prop. If I recall the prints weren't accurate as regards port design. I have been talking with Lee from ageless engines for years as I've been very interested in the Hercules he was working on. He did have an original cylinder assembly he was working from. But I don't think he compensated for a non supercharged model and wasn't about to spend the hours to solve that issue. He has an amazing amount of time into what he has done now. I have found a lot of things online like port and sleeve timing degree chart & dimensions for the sleeve & cylinder ports from Brian Perkins Aquila. It might be a good idea to look at that as it would give an un-supercharged view of the ports. I do have digital maintenance manuals but there are no dimensions except tolerances. Somewhere I have the gear chart for the sleeve drive. The thing that concerns me is that if what you have there is based off the the real deal you will need a working supercharger for it to run. Just some food for thought!
Art
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Offline john mills

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #40 on: January 25, 2022, 06:52:24 AM »
hi
the pictures i have are in  that ricardo book mine is the forth edition printed in 1967 bought in 1967 
    John

Online Vixen

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #41 on: January 25, 2022, 11:15:47 AM »
Hello Art,

It is never too late for you to join this or any other conversation. Your input is always very welcome.

You are right; there are some things which don't scale. Centrifugal superchargers are one. You would need to spin the 1/4 diameter impeller at jet engine speeds to create any pressure at all. I will therefore need to consider this engine as a normally aspirated engine rather than as a supercharged engine. This will require changes to the port size and timing diagram. We need to get away from 'hot' high performance port timing to something much milder. The required changes will probably end up being similar to those of the normally aspirated Barr and Stroud engine. The drawings in the final editions of SIC magazine ( issues 83 & 84) are very vague and imprecise (typical Bob Washburn).

Art, do you have any more information about the BAR and Stroud or the Argyll sleeve ports and timing? Can your friend with the running B+S help?

John, Does your edition of Ricardo's work give any further background info on that sleeve valve timing illustration?

Cheers

Mike
« Last Edit: January 25, 2022, 02:35:25 PM by Vixen »
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Online Art K

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Online Art K

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #43 on: January 25, 2022, 12:42:14 PM »
Especially the blue prints at the bottom of the page.
Art
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Online Vixen

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Re: Bristol Hercules sleeve valve radial engine plans drawings
« Reply #44 on: January 25, 2022, 12:53:16 PM »
Thank you Art
Brian gave me those drawings years ago before he passed away. The Aquilla engine was supercharged, like the Hercules.
Do you have any port information regarding the NA Barr and Stroud?

Cheers

Mike
« Last Edit: January 25, 2022, 09:13:06 PM by Vixen »
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