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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Glow Engines >> Dreaming - is it possible to turbo a R/C Hobby engine?
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Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 4:22:35 AM   
maxtenet



Posts: 708
Joined: 10/18/2002
From: Towson, MD, USA
Status: offline 		The original question had to do with the possibility of turbocharging a two stroke R/C engine. As I said, I'll grant you its possible, not fuel efficient and its like putting a Cummings V8 diesel in a Yugo. The weight would make it tough to get moving!

Max

p.s. p51,

I'm thinking a side by side twin with a common combustion chamber. intake on one cylinder, exhaust on the other. Give me some time to think it through! With a supercharger it might be the highest output engine yet!

(in reply to 99GrandTouring)
       Post #: 26

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 4:34:01 AM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Max:

Two pistons in a common bore, with two crankshafts is old hat. It is called an "Opposed Piston" engine.

The Fairbanks-Morse diesels that were commonly used in US submarines were built that way.

By having the exhaust side crank lead the inlet side crank by a few degrees the cylinder had the inlet ports open after the exhaust had closed, allowing the scavenge blower to give a slight amount of supercharging.

Hope this doesn't "Bust your bubble."

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to 99GrandTouring)
       Post #: 27

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 5:11:31 AM   
maxtenet



Posts: 708
Joined: 10/18/2002
From: Towson, MD, USA
Status: offline 		Nah,

I know what an opposed piston engine is! I'm not talking about that. I'm talking about two cylinder bores vertically next to each other, one crankshaft, with only the head and combustion chamber in common. The pistons would hit TDC and BDC at the same time. It would look like an inline twin. Mixture would come in one cylinder and out the other with a bypass port between them to efficiently remove the burnt gasses. Only anticipated problem is that one side would probably run significantly hotter than the other. Hard to explain!


Max

(in reply to 99GrandTouring)
       Post #: 28

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 6:30:15 AM   
Flypaper 2



Posts: 4337
Joined: 3/29/2002
From: Kingston, ON, CANADA
Status: offline 		Max ;
I've seen one something like that but two cyls side by side,. Two cranks geared to a common shaft. Single combustion chamber between the cyls. Intake ports in one cyl, exhaust in the other. Both pistons go up and down at the same time. Never heard any more about that one. Another one by the wayside.

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Dreamed I was a muffler. Woke up exhausted.

(in reply to 99GrandTouring)
       Post #: 29

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 7:11:25 AM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Okay, Max.

The Puch (Germany) two-stroke motorcycle engine of the 50s and early 60s was what you are contemplating, except Puch had both conrods going to a single crankshaft throw.

The cylinder bores were parallel so rod angularities were a bit extreme, but it did allow the exhaust opening to have a good lead over the bypass opening, and again, as in the opposed piston engine, the bypass port stayed open after the exhaust had closed. And they did, naturally, have a single combustion chamber spanning the two cylinders.

The Puch engine was also able to use crankcase compression for scavenge pumping so the use of a separate blower was not required.

Separate cranks with parallel cylinders has also been done. See the Ariel "Square Four." And a Vee-4 with hemi chambers and a single piece head covering all four cylinders, in the Lancia "Appia." And an H-16 with sleeve valves, the Napier "Sabre." Not to mention an H-16 with three overhead cams on each bank, from BRM. Figure that one out. BMW built what was called the "Porcupine" engine with four valve cylinders, and it still had hemi chambers. Another one for you to figure out how they did it.

The final example I'll give you is the "Mixmaster" engine. Twelve cylinders, all the bores parallel to the crankshaft. Six around one end, and six around the other. One cylinder on each end was paired with a cylinder on the other end, a one piece rod went from one piston to the other of the pair. The crank had a wobble plate that fitted into a notch in the rod to drive and be driven by the rod.

Point is, whatever you may think of, it's probably already been tried, and discarded.

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to 99GrandTouring)
       Post #: 30

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 7:56:34 AM   
reelrazor


 

Posts: 37
Joined: 9/5/2003
From: Cheboygan, MI, USA
Status: offline 		Yep, everything that has been talked about here has been done before. Some of the ideas were ahead of their time due to material limitations.

Earlier: "it is theoretically impossible to increase the PSI of the incoming air mixture above atmospheric pressure thus precluding the ability to supercharge or turbocharge a two stroke effectively."

Now: "As I said, I'll grant you its possible, not fuel efficient and its like putting a Cummings V8 diesel in a Yugo. The weight would make it tough to get moving!"

Turboed two strokes are a reality, a potent reality. Ceramic technology is now at the point where a small turbo could be cast cheaply and applied in an RC application. The minimal weight of such a unit might very well still be lighter than a big tuned pipe, with possibly a greater return. An added advantage would be a large space savings compared to a pipe that necessarily needs to occupy many cc's of space(hot space at that).

Barring exotic fuels(such as what were banned in Formula 1 a few years back)with natural aspiration, the highest specific outputs have been achieved by two stokes of the 'typical' configuration(360bhp per liter). These numbers DO get beat by blown engines, both turbo and supercharged, mostly in four strokes(drag cars, F1 and even the F1 cars have trouble getting there). I think that turbo two strokes are a way forward and that here on a small scale is a good place to develop this further.

****ohh, and adding a blower often IMPROVES fuel efficiency


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JGW

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       Post #: 31

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 9:53:45 AM   
taildraggerdave


 

Posts: 957
Joined: 8/30/2002
From: Sun Valley, CA, USA
Status: offline 		I hate to be picky but the correct spelling is Cummins........no "g"
I work in the heavy equipment industry (on Caterpillar) and it is interesting how many people do call them Cummings.........
Most turbos run on sleeve type bearings that are slip fit in the bearing housing and slip fit over the turbine shaft. Nothing special. As long as they have oil everything is ok.

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Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 10:18:47 AM   
David Cutler



Posts: 2163
Joined: 9/13/2002
From: Los Angeles, CA, USA
Status: offline 		[QUOTE]Originally posted by William Robison
Max:

Two pistons in a common bore, with two crankshafts is old hat. It is called an "Opposed Piston" engine.

The Fairbanks-Morse diesels that were commonly used in US submarines were built that way.

[/QUOTE]

. . . and the Leyland L60 horizontally opposed two stroke tank engine in the Centurion, and later, the Chieftain tanks.

6 cylinders, each with 2 pistons driving two crankshafts at either end of the crankcase. It was a 2 stroke, with porting in the cylinders, much the same as a model 2 stroke engine, and would run on any fuel.

http://www.rememuseum.org.uk/vehicles/trrv/vehchief.htm

-David C.

(in reply to 99GrandTouring)
       Post #: 33

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 10:28:58 AM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Dave:

You will notice he also said V-8 when he mentioned Cummins. Not to mention that the Cummins 555 V-8 was possibly the most unreliable truck engine ever made.

Of course Caterpillar tried to equal the "Triple Nickle" with the 3208. A 3208 that ran 50 hours was excellent life for the early models. Well, maybe 200 hours is more correct.

But while Cummins just dropped the 555, Cat has gotten the 3208 developed into a pretty nice engine. 3406B was always better, though.

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

(in reply to 99GrandTouring)
       Post #: 34

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 11:01:58 AM   
taildraggerdave


 

Posts: 957
Joined: 8/30/2002
From: Sun Valley, CA, USA
Status: offline 		Bill,
The 3400 series of engines have helped keep Caterpillar a leader in engine manufacturing. The 3406B is now an "E" with mechanically actuated, computer controlled fuel injectiors. The technician (me) can hook a laptop computer into the machine or truck and usually diagnose the problem from there. Wow, times have changed.
Not r/c related in any way except that this allows me to buy more planes......
The 3208 does make a great anchor

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       Post #: 35

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 11:10:34 AM   
David Cutler



Posts: 2163
Joined: 9/13/2002
From: Los Angeles, CA, USA
Status: offline 		[QUOTE]Originally posted by William Robison
Dave:

You will notice he also said V-8 when he mentioned Cummins. Not to mention that the Cummins 555 V-8 was possibly the most unreliable truck engine ever made.

[/QUOTE]

Ah Yes!

The Cummins V8 had it's fair share of service engineers loving it for keeping them in work in the UK too!

-DC

(in reply to 99GrandTouring)
       Post #: 36

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 6:25:15 PM   
Flypaper 2



Posts: 4337
Joined: 3/29/2002
From: Kingston, ON, CANADA
Status: offline 		There was a German aircraft diesel engine with opposed crankshafts one on top of the other, with pistons coming together in the centre. there is a cutaway engine in the aviation museum in Ottawa. Can't remember who made it though. Junkers maybe?

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Gord
Dreamed I was a muffler. Woke up exhausted.

(in reply to 99GrandTouring)
       Post #: 37

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 10:22:52 PM   
maxtenet



Posts: 708
Joined: 10/18/2002
From: Towson, MD, USA
Status: offline 		Wow,

I'm truly amazed at the amount of info and interest this topic has generated. I guess I'm not the only total gearhead out there. It's nice to know others are into this stuff as much as I am. Thanks for the comments!

Max

(in reply to 99GrandTouring)
       Post #: 38

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 10:49:05 PM   
David Cutler



Posts: 2163
Joined: 9/13/2002
From: Los Angeles, CA, USA
Status: offline 		[QUOTE]Originally posted by Flypaper
There was a German aircraft diesel engine with opposed crankshafts one on top of the other, with pistons coming together in the centre. there is a cutaway engine in the aviation museum in Ottawa. Can't remember who made it though. Junkers maybe? [/QUOTE]

Yep:-

http://www.stobbe.dk/industrial-products/technical-literature/combustion-engines/junker/junkers.htm

-DC

(in reply to 99GrandTouring)
       Post #: 39

Dreaming - is it possible to turbo a R/C Hobby engine? - 9/6/2003 11:22:20 PM   
reelrazor


 

Posts: 37
Joined: 9/5/2003
From: Cheboygan, MI, USA
Status: offline 		[QUOTE]Originally posted by taildraggerdave
I hate to be picky but the correct spelling is Cummins........no "g"
I work in the heavy equipment industry (on Caterpillar) and it is interesting how many people do call them Cummings.........
Most turbos run on sleeve type bearings that are slip fit in the bearing housing and slip fit over the turbine shaft. Nothing special. As long as they have oil everything is ok. [/QUOTE]

****Just as a clarifier: In my post above, that 'Cummings V8' was a direct quote from(someone else's) earlier post.


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JGW

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Dreaming - is it possible to turbo a R/C Hobby engine? - 9/7/2003 1:05:46 AM   
taildraggerdave