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Art-J
01-30-2004, 09:23 AM
O.K. here's the question for extraordinary engines experts. I'm curious about construction of Bristol Perseus, Hercules and Centaurus radial, sleeve-valve engines. How the hell did those valves look like? I've found some drawings and description here...
http://restored-classics.com/willy/page6.html
...but on the other site I've read that Bristol used Burt-McCollum system with one concentric sleeve (instead of two in Knight system from the link above). No additional drawings though... It's difficult to judge something just from photos of these engines. Maybe some of you can provide more precise information?
Thanks in advance! http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

http://server5.uploadit.org/files/Haribo-Zeke_small_3_txt.jpg

Art-J
01-30-2004, 09:23 AM
O.K. here's the question for extraordinary engines experts. I'm curious about construction of Bristol Perseus, Hercules and Centaurus radial, sleeve-valve engines. How the hell did those valves look like? I've found some drawings and description here...
http://restored-classics.com/willy/page6.html
...but on the other site I've read that Bristol used Burt-McCollum system with one concentric sleeve (instead of two in Knight system from the link above). No additional drawings though... It's difficult to judge something just from photos of these engines. Maybe some of you can provide more precise information?
Thanks in advance! http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

http://server5.uploadit.org/files/Haribo-Zeke_small_3_txt.jpg

ddsflyer
01-30-2004, 09:49 AM
The sleeve is a free floating cylinder liner that ocillates up and down as well as twists back and forth to line up a port in the sleeve with the intake or exhaust manifold opening in the cylinder proper. It is actuated by a cam driven off the crankshaft. The Napier Sabre series liquid cooled engines were also sleeve valves as memory serves. The radial engines were extraordinarily smooth and quiet with respectable hp/cu. in output and reliability, but the inlines were somewhat more problematical.

Baron pilots do it with class!

lbhskier37
01-30-2004, 09:58 AM
Thats a clever design, Ive actually never seen one before. Seems to me like distortion of the thin sleave could be a problem. Does anyone know if this was a problem?

http://lbhskier37.freeservers.com/pics/Killasig2.jpg (http://www.il2skins.com/?action=list&whereauthorid=lbhkilla&comefrom=display&ts=1049772896)
"Only the spirit of attack, born in a brave heart, will bring success to any fighter aircraft, no matter how highly developed it may be." Adolf Galland

LilHorse
01-30-2004, 10:15 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Art-J:
O.K. here's the question for extraordinary engines experts. I'm curious about construction of Bristol Perseus, Hercules and Centaurus radial, sleeve-valve engines. How the hell did those valves look like? I've found some drawings and description here...
http://restored-classics.com/willy/page6.html
...but on the other site I've read that Bristol used Burt-McCollum system with one concentric sleeve (instead of two in Knight system from the link above). No additional drawings though... It's difficult to judge something just from photos of these engines. Maybe some of you can provide more precise information?
Thanks in advance! http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

http://server5.uploadit.org/files/Haribo-Zeke_small_3_txt.jpg <HR></BLOCKQUOTE>

My best advice would be for you to get a hold of a copy of Allied Aircraft Piston Engines of World War II by Graham White. Many cutaway and exploded diagrams of Bristol and others engines.

Anyway I'll try quickly to explain. The sleeve looks like a soda can open at both ends. Spaced out over about one side of the can are four holes. Two set at the top at the same level are (if I recall correctly) exhaust ports. One near the bottom is an intake port and one in the middle is common. So you get two intake and three exhaust for four holes. The way you get a common port is due to the motion of the sleeve during the cycle. Imagine at the very bottom of the sleeve there is a little hole into which the "handle" of a little "crank" is inserted. At the axis of the crank is a shaft that is spun from being geared off the crankshaft. As the little crank on the sleeve turns, the sleeve goes up and down and also twists side to side. This motion during the four stroke cycle lines up two ports for intake stroke. Seals them all for the compression and power strokes. Then positions three openings for the exhaust stroke. It's the opening in the middle that shares intake and exhaust duties. I hope this makes it a little more clear.

edit: It may be that I have the number of holes reversed for intake and exhaust. It could be two for intake, one for exhaust and one common (been a while since I looked at the book). Either way it works roughly as I described above.

Covino
01-30-2004, 10:28 AM
I had a tethered P-51 model plane with an engine like that. Took the engine apart countless times for cleaning.

Bansai Potato
01-30-2004, 10:29 AM
[QUOTE]Originally posted by lbhskier37:
Seems to me like distortion of the thin sleave could be a problem. Does anyone know if this was a problem?

Indeed it was a very big problem for the inline Napier Sabre engines, cooling was such a problem for all of those moving (valve) parts that i think the early sleeve valves were having to be changed every 5 - 8 hours of engine running time.

http://homepage.hispeed.ch/Ede_EAF92/EAF/24890632.92EastIndiaSquadronpersonnel.jpg

JR_Greenhorn
01-30-2004, 10:32 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by lbhskier37:
Seems to me like distortion of the thin sleave could be a problem. Does anyone know if this was a problem?<HR></BLOCKQUOTE>Aye, it was indeed a problem. The sleeves were prone to distortion. In such an engine proper warm-up before loading is crucial.

I remember reading somewhere of the regularity that Tempests with the Napier Sabre had to be started and warmed during the winter months to keep them combat ready. It was every few hours, if memory serves.

Another problem was manufacturing the sleeves accurately enough. I can imagine cutting tool chatter would be a problem with such a thin wall thickness for such a large diameter. I also remember reading of a centerless grinder obtained with some difficulty from Pratt & Whitney to manufacture sleeves.

One of the obvious benefits of the sleeve valve design, in addition to the aforementioned redution in mechanical noise, is the decreased height of the cylinder. This allowed for smaller external engine diameters, or in the case of the Bristol Centaurus, increased displacement in a package the size of other radials. If you can find bore & stroke dimensions, you will find that the Centaurus has a 7.0" stroke, vs. the 6" or so strokes common among poppet valve radials.



Here are some pictures of the Centaurus' sleeves & cylinders
http://www.enginehistory.org/buckel_galleries.htm

A page on the Napier Sabre:
http://www.eagle.ca/~harry/aircraft/tempest/sabre/
It disscusses the use of Bristol sleeves in the Sabre

Art-J
01-30-2004, 10:46 AM
Thanks to all of you for your responses. http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif
P.S. - Greenhorn, these photos on enginehistory.org are great indeed

http://server5.uploadit.org/files/Haribo-Zeke_small_3_txt.jpg

tenmmike
01-30-2004, 11:01 AM
FIRST OFF BUD i wrote like 2 pages of stuff for you on this and then lost all it to a power outage ..even though i have a unopened power supply setting next to me...do to the wind storm here we having in the pacificnorthwest.although i have no first hands on of it i do understand the theory well..my theoretical understanding is a higher frictional loss and is fairly hard on the oil to to more exposure to higher temp(localised oil temps cause coking of the oil) and warpage of the sleeve and shearing of the oil thus a higher oil degradation rate and dificulty in mfr of the parts to the tolerance set..the only good things i see are stable valve timing and no worry of valve or spring breakage which at the time was no small concern even though relative to today the stress imposed on valve springs is far higher now then on engines of that time (we now have far better springs/material..............this as i said is not first hand knowledge just ..my observation of the engine... and seeing many more potential problems do to added complexity..../////any way im not going to write the whole thing again so click this link http://www.geocities.com/kiwiengineer2002/sleeve.html
greenhorn thanks for that napier link NOTE original poster im not mad at ya just i started writing about 3 min after your post ..and lost it all http://ubbxforums.ubi.com/images/smiley/16x16_smiley-mad.gif
http://images.ar15.com/forums/smiles/anim_50cal.gif U.S INFANTRY 1984-1991

[This message was edited by tenmmike on Fri January 30 2004 at 10:19 AM.]

LilHorse
01-30-2004, 11:32 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by lbhskier37:
Thats a clever design, Ive actually never seen one before. Seems to me like distortion of the thin sleave could be a problem. Does anyone know if this was a problem?


<HR></BLOCKQUOTE>

Yes, but I believe it was more of a problem with those sleeves that Napier manufactured versus those made by Bristol. That's why Napier turned to Bristol to supply them with the sleeves for the Sabre. It seems that Bristol was better able to machine and coat the sleeves. Though I forget what material was used in coating.

LilHorse
01-30-2004, 11:41 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Art-J:

P.S. - Greenhorn, these photos on enginehistory.org are great indeed

<HR></BLOCKQUOTE>

Boy are they! Did you notice the marks on the side of the sleeve from the heat of the exhaust port. Talk about stress on materials. Also, the valve gear train would put a Swiss watch to shame LOL.

LilHorse
01-30-2004, 11:45 AM
Oops! Edit-Quote dislexia today

Arms1
01-30-2004, 01:03 PM
if you are anywhere near Trenton Ont. Canada, IIRC the RCAF museum there has an actual cutaway of a sleeve valve engine from a halifax
also its in the hanger where they are restoring the halifax so you have to go there when that area is open to the public

JR_Greenhorn
01-30-2004, 02:14 PM
Also related to the heat and sleeve distortion problems is the cooling ability of the design. Without the sleeve valve around the cylinder there would otherwise be a certain amount of metal and finning on air-cooled engines, or the water jacket on liquids. With the sleeve valve in place the clyinder sleeve (the sleeve the piston slides against) must be thinner, and is more isolated from the cooling medium. Certainly the clearance that affords the movement and expansion of the valve sleeve impeeds heat transfer from the cylinder to the cooling system. Some of this lost heat transfer is absorbed by the valve sleeve and retained in the engine.

Another problem related to heat transfer and the sleeve valve in these engines is the relative temperature difference between the air flowing through the ports. On the intake ports, the incoming air is signficantly cooler than anything else in the engine, while the exhaust gasses leaving through the exhast ports are among the hottest. Both of these flows move through the same sleeve, and as tenmike mentioned, through the same port. In effect the flowing air is alternately trying to heat and cool the ports as it passes through. Obviously this is a recipe for distortion of the sleeve.

In poppet valve engines these problems also exist, but the valves are separate. That is why some engines had sodium-cooled exhaust valves (like the DB600 series), while the intake valve is self-cooled by the intake charge. Whether cooling measures are taken for the valves or not, the placement of poppet valves provides hot spots in the cylinder that help induce detonation. Sleeve valve engines don't have this problem and can run higher compression ratios and boost levels safely--a benefit of sleeve valve engines.

MiloMorai
01-30-2004, 09:31 PM
Another site.

http://www-g.eng.cam.ac.uk/125/achievements/ricardo/#9.%20SLEEVE

As was suggested, look in the Allied A/c Piston Engines of WW2 which has a wealth of info and not just on the Bristol engines. Well worth the money.



Long live the Horse Clans.

DaBallz
01-31-2004, 03:45 AM
Bristol and Napier sleeve valve engines used a 5 port recirculating sleeve. The sleeve was on a crankshaft with a ball end connection that raised and rotated the sleeve. This effectivly gave 2 exhaust ports and 3 intake ports. The sleeves were prone to distortion at high power settings and did require a strict warm up regimen. The chief advantages were the lack of valves and the resulting hot exhaust valve, allowing higher compression and boost on lower octane fuel. Also the overall diameter was smaller for the same displacement.

Disadvantages were the increase in complexity and decrease in reliability, especially in the case of the Napier Sabre.

Higher octane fuels and better poppet valve engines along with jet engines stopped the sleeve valve engines from spreading, although most of the big engine manufacturers experimented with them.

Oil consumption was to high for sleeve valves to really catch on in automobiles. the Willy's Knight was on a par with contemorary flat head engines but was an oil burner.

Da

RAF74_Buzzsaw
01-31-2004, 04:03 AM
Salute

Some disinformation here.

Yes, the Napier Sabre engines had problems to start.

But eventually they produced more horsepower per cube than any other standardly manufactured aero engine.

A quote from the Hawker Tempest site:

"When the engine reached squadron service, there were cases of ground maintenance personnel misadjusting the automatic boost control, allowing far too high manifold pressure at low rpm, resulting in detonation and serious engine damage.
After the debacle of the early Sabres, the engine became reliable and increasingly powerful. By 1944, in Sabre V form, it became an excellent power plant. Several of the improvements incorporated into the Sabre V were relocating the outboard, overhung supercharger clutches to behind the crankcase, thus reverting to conventional in-line configuration.
The double-entry, two-sided supercharger impeller was replaced with a single-sided impeller. Carburation was improved in 1942 with the introduction of the Series IV, by replacing the four-barrel SU unit with a Hobson-RAE single-point fuel-injection unit spraying atomized fuel into the eye of the now single-sided supercharger impeller.
The Sabre VII was similar to the V; the primary difference was the use of ADI and the strengthening of the internal components. From its 2238 cu.in. displacement a phenomenal 3500 hp was achieved at 3850 rpm. Finally, Napier test ran a Sabre at 4000 hp with ADI. No other production aircraft engine has ever equaled these truly impressive numbers !"

Compare that with the amount of horsepower produced by the Daimler Benz's.

http://user.tninet.se/~ytm843e/tempest.htm

DaBallz
01-31-2004, 07:35 PM
It is best that you give Mr White and the SAE press
a credit when printing paragraphs out of their
book verbatum.

The Sabre never equaled the reliability of
contempoary poppet valved engines. Yes
they achieved very high specific horsepower numbers
but none of those high powered test engines
ever saw service.

As to the most powerful piston engines to see
active millitary or commercial service, the late
P&W R-4360s were rated as high as 3,800hp.
Late Wright R3350TCW's were rated at up to 3,700hp.
Test models of the P&W R-4360VDT were tested at
over 4,500hp and to top the prototype list
was the Lycoming XR7755 was rated at 5,000hp
and it had plenty of room for development.
Had jets not taken over it would likely have
been developed to over 6,000hp.

Oh I might add, the Allison V-1710-127 developed
2,900hp on 1710 cubic inches of displacement.
That's a higher specific power output than the
Napier Sabre ever saw.

That the Napier Sabre program was not dropped
was a sign of the desperation of WAR.

Da