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Thread: Oddball engines and prototypes

  1. #1366
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    If any of you colonial chappies are ever in southern england, I would say the Sammy Miller museum is well worth a visit as he's got quite a lot of experimental and prototype stuff. On the other hand, we took the grandchildren to the Haynes museum last week and I wouldn't bother going there...
    Talking of recommendations, just read the Mike Sinclair book, sent halfway round the world to get here! Thanks, Grumph (Greg?).
    Last edited by guyhockley; 17th April 2017 at 01:10. Reason: spell check thought Grumph was one of the seven dwarves.

  2. #1367
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    Quote Originally Posted by guyhockley View Post
    If any of you colonial chappies are ever in southern england, I would say the Sammy Miller museum is well worth a visit as he's got quite a lot of experimental and prototype stuff.
    Seconded, I've also posted a few pics which were taken on my visits there.

  3. #1368
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    20th January 2010 - 14:41
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    More research required...

    Kinky is using a feather. Perverted is using the whole chicken

  4. #1369
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    22nd November 2013 - 16:32
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    Had a bit of a look at it, but it fires both cylinders simultaneously. So, what about a slight variant:

    DSC_1279.JPG

    Upside: Smoother running and a more compact (2 into 1) exhaust.
    Downside: Reduced stroke on top pistons (go bigger bore?) & lots of other things I haven't thought about

    Have to think a bit more about the kinematics and pivots, but it's an alternative.

  5. #1370
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    Ken, you could increase throw of outer cranks to balance stroke of pistons?

    Also, it looks like the outer links need articulation, and perhaps one outer link and crank could be deleted?

  6. #1371
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    Can I post SAE papers here? I have two on the OPEC engine. One is for a truck engine with the electric turbo and the other is for a 5 KW generator unit that used piston pumps on the outboard cylinders. China was supposed to start producing the engine, but I'm not sure what happened. The company web site is gone.

    Lohring Miller

  7. #1372
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    I have seen that engine quite a few times being advertised as a "breakthrough!!" - there has been a lot of hype talk about it and how China was poised to turn it into reality, but has it actually become a viable reality as yet?
    The shape of the thing is a problem for a start (certainly for private cars and bikes). What has it got going for it that would make people change from the tried and true? - it does have good balance and the benefit of a lot of two stroke research of course (although mainly for competition) but it most probably would still have many of the current two stroke problems to stop it from coming on line! - not least being opposition to the words "two stroke".

    First, the awkward layout (shape), two normal conrods and four more massive ones in tension? (ie in a twin cylinder). Poor combustion chamber shape, The two stroke bugbear of petrol and oil mixing and escaping through the exhaust? Large exhaust chambers? and why does it have to be horizontally opposed, when the balance could still be sorted with a common inline cylinder layout?

    Then there is the prevailing, unfair opposition to the two stroke nowadays, supposedly because of pollution, which is only the "seen to be" truth, considering China's pollution problems, they also might not be so receptive to it anymore.

    Obviously the USA or anyone else in general isn't going to take much interest in it and maybe China is taking note of that!
    (ie except Bill Gates ...... then I guess he is America!) - I think it has probably swallowed a lot of Bill's money already!

    Anyway we all know Elvis aint dead ........ I do hope the two stroke aint dead either!

    Sorry to be a killjoy but we have to face facts - surely?
    Freedom of speech is important but if what we say is incorrect, our peers will quickly put us right.
    P.C. will eventually destroy our right to tell the truth.

  8. #1373
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    Quote Originally Posted by WilDun View Post
    ...the awkward layout (shape), two normal conrods and four more massive ones in tension? (ie in a twin cylinder). Poor combustion chamber shape, The two stroke bugbear of petrol and oil mixing and escaping through the exhaust? Large exhaust chambers? and why does it have to be horizontally opposed, when the balance could still be sorted with a common inline cylinder layout?
    A textbook KISS violation .

  9. #1374
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    I tend to agree. A simpler version is being touted by Achates Engines. The electric turbo is the breakthrough in my opinion. It's a more efficient and compact compressor than the Roots blowers used in the past. Electronic engine management should also help. However, if battery technology keeps going like it has been, all these points will be moot. If you can seriously consider electric propulsion for aircraft, cars and trucks should be easy.

    Lohring Miller

  10. #1375
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    Quote Originally Posted by Frits Overmars View Post
    A textbook KISS violation .
    But the devils into details
    i just looked at the description seen asymmetrical exhaust and inlet and thought uniflow.

    i think the answer for the 2t is either stopping the hydrocarbons escaping out of the ports.
    At low revs or sending them back in there again after they escape.
    A lot of EGR stuff has been done on 4ts for NOX
    It seems they use it as an combustion insulator and to prevent detonation.
    Of course the presnce of hdrovcarbons in the 2t exhaust might not help.
    The actual EGR system is taken into consideration when the engineers design a particular engine. Such modern engines will ping heavily due to excessively high combustion temperatures and pre-detonation. In such cases the exhaust reintroduction not only reduces combustion temperatures but also has the effect of raising the mixture octane to reduce pinging (pre-combustion).
    Something as simple as a rehash of the vacumn flapper butterfly valve Yamaha used on the Daytona special with a egr bypass would work.
    Daytona special butterfly.jpgDaytona Special stuff.jpg
    The valves are controlled by engine vacuum and throttle opening. When the carburetor slides are raised less than 3.3mm, a valve located at the carburetor linkage remains closed. With that control valve closed, vacuum from the intake manifolds opens a dashpot located underneath the carburetors, behind the cylinders. That dashpot pulls butterfly valves closed via an adjustable rod linkage which runs underneath and between the cylinders to the exhaust valve assembly.
    When the carburetor slides are raised more than 3.3min, the control valve opens a line leading from the airbox, dashpot vacuum drops, and the butterfly valves spring open. The valves are either open (under most conditions) or closed (under deceleration and very small throttle openings) and do not hold at any position m between. When the control valve is open, the line from the airbox constitutes a coitrolled air leak, which is compensated for in carburetor jetting. (A one-way valve in the intake manifold vacuum lines prevents any reversal in the emissions system air flow.)
    The valves are effective because a twostroke is less efficient with the throttle closed, especially when decelerating. The rich air/fuel mixture tends to run right through the cylinders and out the exhaust without complete combustion, and the lack of compression braking effect allows a decelerating two-stroke to coast with the throttle shut for relatively long distances. That adds up to lots of emissions during deceleration. The butterfly valves work on a sort of potato-up-the-exhaust-pipe principle - with the exhaust plugged, emissions aren't a problem. In actual fact, it isn't that dramatic. When open, the exhaust manifolds are 1-7/16 in. diameter, for a combined exhaust area of 3.25 sq. in., not counting the obstruction caused by the open butterfly valves. With the valves closed, exhaust exits through two quarter-inch holes in each valve, for a combined exhaust area of 0.2 sq. in. It isn't a case of total blockage, but it gets the job done.
    http://www.oocities.org/motorcity/fl...CWArticle.html
    IF you want something that really fails on KISS
    Maybe get rid of the crankcase pumping and use something like this.
    More research required...

    Kinky is using a feather. Perverted is using the whole chicken

  11. #1376
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    Quote Originally Posted by lohring View Post
    I tend to agree. The electric turbo is the breakthrough in my opinion. ......... However, if battery technology keeps going like it has been, all these points will be moot. Lohring Miller
    Yes Lohring I tend to agree (in fact fully agree) that gas turbine powered generators and electric motors are in the near future. Having said that, the good old two stroke piston engine also has a niche with it's convenience, good power to weight ratio and above all, it's instant power without the help of heavy batteries etc,
    Until the battery weight issue is sorted, the two stroke still stands a chance and until the efficiency issues with the smaller turbines is sorted, the two stroke could be able to fill this role as a viable powerplant also. (ie if it can demonstrate some good manners in the preservation of the environment!).
    I thought the smokiness (or performance) of the Suter at the TT did not help the image of the two stroke at all! - but a very brave effort nevertheless!
    Freedom of speech is important but if what we say is incorrect, our peers will quickly put us right.
    P.C. will eventually destroy our right to tell the truth.

  12. #1377
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    I hate to be an electric power advocate in an IC forum. I've loved two strokes since I built a 10 cc model airplane engine in high school shop. However, I have a little experience with electric power. In 2008 we went 98+ mph two way average to set the world electric powered boat speed record that still stands. Lithium polymer batteries were the secret even though we ran a brushed motor and relatively inefficient speed control. The batteries cost $14,000 wholesale direct from Enerland for 42 6 cell packs. Today much better lithium polymer batteries would cost $6,000 retail. The boat's range was several kilometers at top speed. Today you could drive a bigger hydro to an over 150 mph record with a used Tesla, or similar, power plant. At moderate speeds the range should be a lot greater.

    My Subaru BRZ has around a 300 mile range on mostly highway driving with great handling and reasonable acceleration. The Tesla Model S, according to my friends who own one, has around a 300 mile range with great handling and unbelievable acceleration. It costs at least 3 times as much. We will see how the upcoming moderate priced electric models from many manufacturers do.

    Lohring Miller

  13. #1378
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    Quote Originally Posted by lohring View Post
    I hate to be an electric power advocate in an IC forum. I've loved two strokes since I built a 10 cc model airplane engine in high school shop. .......... However, I have a little experience with electric power. ......... Today much better lithium polymer batteries would cost $6,000 retail ......... The Tesla Model S, according to my friends who own one, has around a 300 mile range with great handling and unbelievable acceleration. It costs at least 3 times as much. ......... Lohring Miller
    So are you only interested in straight electric power as opposed to hybrid? I was just thinking of getting past the heavy and expensive battery situation by also utilizing lightweight IC engines and using less battery, ie using batteries only as a "buffer" in the transmission in preference to the expensive gearing involved in differentials and auto transmissions of the road vehicles today. I don't think the generators and motors themselves are horrendously expensive to produce - ( controls probably quite complex though - I imagine).. If the two stroke can clean up it's act then it must be a serious contender for this position at least in the near future!.

    Airbus (I think it was Airbus) it seems are now experimenting with hybrid power instead of using pure electrically powered aircraft (which they originally started off with).
    Freedom of speech is important but if what we say is incorrect, our peers will quickly put us right.
    P.C. will eventually destroy our right to tell the truth.

  14. #1379
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    Quote Originally Posted by guyhockley View Post
    Here's a 3 cylinder radial in a bike.
    I hadn't heard of Charles Redrup before seeing his 3 cylinder radial, at Sammy Miller Museum a few years ago.

    I now appreciate that he had quite a remarkable career, designing an engine almost every year between 1896, when he was 18, and 1953. The designs included:
    a steam engine
    rotary supercharged two cylinder four stroke motorcycle engine
    three cylinder aero engine with contra rotating propellers
    four cylinder sleeve valve car engine
    six cylinder radial motorcycle engine
    six cylinder double-ended two stroke axial marine engine
    five cylinder axial water cooled car engine
    seven cylinder axial engine
    nine cylinder poppet valve axial bus engine
    nine cylinder rotary valve axial bus engine
    eight cylinder opposed piston axial engine
    three cylinder axial wobble plate motor cycle engine
    three cylinder OHV radial motor cycle engine (as posted above by guyhockley)
    eight cylinder opposed piston axial cam aero engine

    His patents included a single sleeve valve engine, and a double ended wobble plate axial engine.

    He was known as "the knife and fork man", which was something to do with him doing development work in his "simple" home workshop.

    Some more info and images here:
    http://www.fairdiesel.co.uk/Redrup.html

    The first photo below is the "Barry" engine c1903. It's a supercharged rotary two cylinder four stroke side-valve engine.

    It has crankcase compression! On each piston down stroke the air fuel mixture from under both pistons, is fed via a rotary valve, to one of the inlet side valves. Thus each cylinder receives a double charge.

    The cylinders, including transfer pipes and exhausts, rotate around the stationary hollow crankshaft, to which is connected a hose from the carburettor (not shown in photo). The engine is enclosed in a cylindrical perforated canister (also not shown), a lever by the tank has linkage to where the carb hose is attached to the crankshaft, I'm not sure of this is a throttle, or another valve to alter the inlet timing!(also not shown on photo).

    The other photo is a drawing c1936. It shows a section on an axial eight cylinder opposed piston engine. This is a supercharged uniflow two stroke, featuring wobble plates.
    Attached Images Attached Images

  15. #1380
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    From what I can gather, that Bristol Tramways engine was the only successful wobble plate engine ever! - it has intrigued me for a long time!
    We have a company called "Duke" here in Auckland who have developed something similar (probably based on the Bristol engine) which it seems is a success also and no doubt, it has been greatly improved by the use of modern metallurgy.
    It is said to be a very compact and smooth running engine, but I'm sure it would be hard to persuade any engine company to produce it, or to change from a proven design which is already bringing in good profits.
    Freedom of speech is important but if what we say is incorrect, our peers will quickly put us right.
    P.C. will eventually destroy our right to tell the truth.

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  1. WilDun

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