What If?: The Turbine Had Not Been Invented

[AAFO_WSagar]

Just sitting here checking mail for a moment or two before I hit the world of keeping busy and an idea struck me.. What if, for whatever reason, the turbine engine had never been invented and we had continued to develop the piston engine...

Any of you gear heads have any ideas of where we might be today in wresting out the most from the piston aircraft engine?

We have some pretty amazing piston auto engines, indeed.. wondering if, since cruise and climb power needs are so different, would there bey anything like hybrid enigines?

Would the battery needs be too heavy?

Maybe this needs to be in the fantasy section? But the thought has my mind spinning...

[JET1]

we would have some really cool gaz motors!

I would bet that the Wankel concept would have appeared earlier and would have been more refined. as far as aircraft go I'd bet there would be some monster 24 to 36 (or more) cyl water cooled engines but the planes in general would not have been any bigger than the b-36. I'd also bet that there would have been more pusher/tractor combination's like the do 335 flying around.

[W J Pearce]

Re: What If?: The Turbine Had Not Been Invented

Two-stroke, compression ignition, sleeve-valve engines with variable discharge turbines driven from the exhaust.

Think Napier Nomad I and II.

Before that, the linking of existing engines like the V-3420, BMW 803, and DB 610; the R-3350 Turbo Compound which we all know did exist and the R-4360 VDT. Also the German HZ-Anlage concept of an engine in the fuselage whose sole purpose it to provide compressed air for the engines on the wings. Sound familiar to any sport class racer; an engine to drive a supercharger only?

[AAFO_WSagar]

Re: What If?: The Turbine Had Not Been Invented

...sleeve-valve engines...

While I've never actually seen a sleeve valve, I've worked on more than a few regualar valve engines.. From what I've read, sleeves are problematic.. what's the advantage Bill??

[W J Pearce]

Re: What If?: The Turbine Had Not Been Invented

While I've never actually seen a sleeve valve, I've worked on more than a few regualar valve engines.. From what I've read, sleeves are problematic.. what's the advantage Bill??

Initially sleeves were problematic. They required matching each sleeve to each cylinder. They also resulted in excessive oil burn. But, if I remember correctly, Fedden and Bristol resolved these issues to a great degree, which included interchangeability between sleeve and cylinder. So you can replace an old sleeve in an old jug and everything would still work. As I said in a different post, the Air Ministry requested (insisted/demand) Bristol supply sleeves to Napier.

The advantage was smoother, cooler running, fewer parts (less to break), increased efficiency (better flow intake and exhaust), greater resistance to pre-ignition (no hot poppet exhaust valve to pre-ignite) and higher compression. The shape of the combustion chamber can be ideal since there are no poppet valves in the head.

Keep in mind, I'm assuming the 30/40s sleeve valve technology would continue to be refined/enhanced. As it is, all was pretty much dropped mid 40s.

It was Harry Ricardo's belief in the sleeve valve that persuaded both Roy Fedden (Bristol) and Frank Halford (Napier) to go with the sleeve valve. Ricardo also was the influance behind the RR Crecy and Eagle using sleeve valves.

After seeing the Sabre, George Mead (I think) of P&W went back to the states and laid down the X-1800 (H-2240) which changed into the H-3130 and H-3730.

In the early to mid 40s I think the sleeve valve engines were bearing fruit but there was little point to continue. The jet engine was a freaking orchard.

[AAFO_WSagar]

Re: What If?: The Turbine Had Not Been Invented

I'd love to see a sleeve valve some time to grasp the concept. I have a tough time getting things from drawings. I have to admit, it's hard to imagine anything working better than our round valve and stem arangement. The compression of the cylinder helps ensure a good seal..

Again, I'd love to actually see a sleeve valve work!!

I like this discussion, though we all know, the turbine was invented and it's prolly hard to imagine that it would not have been but.. it's still a neat thing to think about and visualize "what might have been"... the music that pistons, and even rotary engines make, simply is not there with the woosh of the jet.

I wonder if things like Dantone's "steam afterburner" would have happened and have been a good thing..

Sure would like to hear what Kerch, Dave Cornell or other engine guys might have to say about some of this...

[W J Pearce]

Re: What If?: The Turbine Had Not Been Invented

Yeah, we are just talking here.

Think of how much "in the way" that poppet valve is as air tries to get in and out of the cyl. I'm sure there is an animation on the web somewhere but, if you could put a mark on the side of a sleeve and watch it, it would rotate in a circle.

Okay I can't finish what I was going to say, I need to do some work right now (meeting). I'll see if I can find some examples when I return.

[FENCELINER]

Re: What If?: The Turbine Had Not Been Invented

http://www.modelenginenews.org/gallery/croft/toms_radial.html

Scroll down and right click to save MOV file.

[Peashooter]

Re: What If?: The Turbine Had Not Been Invented

A cutaway view:

http://www.youtube.com/watch?v=Liqqo8Cdb68

[W J Pearce]

Re: What If?: The Turbine Had Not Been Invented

Hey, those are pretty neat. In the cylinder there are 5 holes; 3 intake and 2 exhaust. On the sleeve there are four holes. One of the sleeve's holes is used for both intake and exhaust. As seen here:

http://www.eagle.ca/~harry/images/BRSL_DES.JPG

The sleeve is attached via an eccentric shaft which enables the circular motion. It is also turning at 1/2 crank speed.

Just to be clear, we are talking mono sleeve as in Burt-McCollum (two separate people) not the Knight design which used two sleeves. The Knight engines burnt a lot of oil.

See this pic for part differences between sleeve and poppet (black line separates the two).

http://www.enginehistory.org/ModelEngines/Perkins/Aquila/SleeveVsPoppet.jpg

[AAFO_WSagar]

Re: What If?: The Turbine Had Not Been Invented

Thanks guys... I can see the "how it works" now.. Still, from the aspect of sealling things, I can see a whole bunch of headaches using sleeves v poppets.. The amount of parts belies the amount of complexity that is lost in the simple up and down motion of the poppet valve.. They have proven reliable in engines for 1000's of hours... Looking at the sleeve valve, throw in some carbon deposits and it just looks like something that would work well.. in a lab...

GREAT discussion, and I'd love to hear from someone who has practical experience with both...

[Plane Nuts]

Re: What If?: The Turbine Had Not Been Invented

The last time I visited the National Automobile Museum in Reno there was a cutaway Willys Knight engine driven by an electric motor if you want to see one up close.

[W J Pearce]

Re: What If?: The Turbine Had Not Been Invented

Thanks guys... I can see the "how it works" now.. Still, from the aspect of sealling things, I can see a whole bunch of headaches using sleeves v poppets.. The amount of parts belies the amount of complexity that is lost in the simple up and down motion of the poppet valve.. They have proven reliable in engines for 1000's of hours... Looking at the sleeve valve, throw in some carbon deposits and it just looks like something that would work well.. in a lab...

GREAT discussion, and I'd love to hear from someone who has practical experience with both...

I too would like to hear from someone with experience because I certainly do not have any. Keep in mind Wayne, this is your what if thread about no turbines.

I think issues with the sleeve valves would have been/were overcome. If you focus on Bristol, whose first sleeve valve ran in 1936 or around there, you will see that it was not just a fling. They stopped making poppet vales and focused on sleeve-valves. They made the Perseus, Aquilla, Taurus, Hercules, and Centaurus. After that, they made jets. Although I do not have exact numbers in hand, they made 1000s of engines and I believe their TBOs were beyond what was "good" for when they were made. Also their BMEPs were inline or in excess of contemporary radials.

I remember carbon being mentioned in the Fedden book so I will have to look into that. I think that Fedden was worried about that but it ended up not being an issue. Something about the circular motion of the sleeve prevented any build-up. But I'm not sure.

All is moot point anyhow. But it is fun to wonder.

[bluffman]

Re: What If?: The Turbine Had Not Been Invented

I have some "rotating cylinder valve" model airplane engines, that run very well. The sleeve rotates a 1/2 the crankshaft speed, and has ports in it, intake and exhaust, making it a four cycle, and the combustion chamber end of the sleeve coninues on out and is the prop shaft. As the engine is running, the cylinder sleeve is rotating at 5000 RPM (with the prop mounted on it) and the piston is going up and down inside it when the crankshaft is turning 10,000 RPM. Damn, it is hard to explain how this works, but I can pull a 18X6 4bladed prop with a 120 size engine, and a 16X8 4 bladed prop wiyh a 90 size engine. With the 2 to 1 gear reduction the engine makes a lot of torque. It is hard to comprehend a piston going up and down 10,000 times per minute inside a cylinder rotating at 5,000 RPM, but it works. CONFUSED? Do a Google for RCV engines, made in England, maybe it will help to understand how it all works. I have one disassembled at this time believe it or not, to build a contra- rotating prop gearbox for the 120 size engine. If there is interest, I will photograph the component parts, and post them.

I am familiar with the Centaurus engine, but this configuration (RCV) engine seems less complex, and more reliable. A multiple cylinder engine could be built, I reckon, would have to do some serious thinking about that though. The engine sounds like any 4 cycle single cylinder engine, not that high pitched scream of a 2 cycle.

That's my 2 cents worth of possibly worthless information, I guess the turbine and jet engines will still rule in the long run, but I, like many of you enjoy the sound of a piston engine, instead of the whoosh, vacuum cleaner sound of a turbine.

Larry

[bluffman]

Re: What If?: The Turbine Had Not Been Invented

I just Googled the RCV web site to see if it was still up, and if you go there and click on model aircraft engines, and click on the RCV 120, there is a exploded view and a good description of how it works, probably better than mine.

Larry