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Thread: Is a four stroke worth the bother?

  1. #11
    not real name 100 Club
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    Is a four stroke worth the bother?

    Excellent stuff Kev. Driving down the cost of aviation by experimentation and the sharing of innovation. Ssdr may not be for everyone but I'm sure the masses will benefit in the long run.

  2. #12
    Diamond geezer 500 Club
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    Is a four stroke worth the bother?

    It is a source of gentle frustration to me that Flylight and Ace Aviation develop trikes that will run on lower power, say, 22-25hp, fitting screaming two strokes to them and limiting their appeal to fun local flyers.

    On G-KEVA Iíve gone for good speed and climb, so have tuned the Briggs engine quite highly, but the standard off the shelf Briggs and Chinese copies do 23-28hp pretty much off the shelf; they are heavy (around 35-40 kilos when Johnís reduction Drive is added) but are really dozy and will run forever, and sip fuel. Not only that they are tough and able to be fixed anywhere in the world with spares from any garden machinery shop.

    Some shy away from what they think might be complex engine work, I understand this but the basic engine with mild parts added is cheap and not a fat lot needs doing to power it to maybe abit less horsepower than mine, so if a Laser or slightly bigger and slower wing than my Cyclone is fitted, this makes a grand little easy -going touring trike, or even just a fun machine that will last years longer than the little screamer two strokes.

    Such a toy would be fine with a small tank as they only burn 6 litres per hour, and the few changes to make it work in a trike are ready to hand with my input. A Brazilian crowd are flying exactly this sort of trike, Kleber Alvez Adorno has sent over several videos.

    Have a look how simple it is to put a Ďhotterí camshaft into the engine to make 28hp, two cheap and simple tweaks to the valve springs (washers under the springs to make them keep them keep the valves pressed home at high revs) and rip off all the governor rubbish and youíve got a nice little aeroplane motor. After all, Johnís already got the reduction belt drive sorted, and that engine is Japanese built and available all over the world.

    Check these video out to see what I mean about simple engines; once the governor rubbish is scrapped the engine gets lighter and simpler as well

    https://www.youtube.com/watch?v=6nlUMtZUcgk&index=15&list=FL1fpKf7jwjf8laM HVjesx-g

    https://www.youtube.com/watch?v=Cx7x65mtvtk&index=16&list=FL1fpKf7jwjf8laM HVjesx-g

    Dan Curtis and Billy Brooks had overheating bothers, but they scrapped the fan cooling for free air; with fan cooling I've had zero issues, even bashing mine to 6000'plus

    Just a thought

    Kev

  3. #13
    Senior Member 500 Club
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    Dec 2006
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    Is a four stroke worth the bother?

    Hi Kev,

    Power to your elbow for pushing four stroke power but you cannot make a case for the four stroke using fuel burn or high revs.

    High revs would be vibration which with a balancer shaft is a thing of the past, maybe high wear rate , not the case if lubrication is ok on the two stroke but possibly component life is shorter and the parts are more expensive but they are fewer in number.

    Fuel burn is efficiency which is effected by weight but the Polini can match your fuel burn and have a better power to weight figure.

    Down side is cost so keep working on the four stroke to get it sorted but if into comparable power to weight you will need to spin your four strokes a lot faster to get the results and you still need to lose a bit of weight.

    When are you going to come down and try the Dragon???

    Mick
    Home soon ;-(

  4. #14
    Diamond geezer 500 Club
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    Is a four stroke worth the bother?

    Love to

    Spinning my engine at 4000 cruise and 4250 climb full chat

    British Hovercraft selling 28hp with governor stripped out and cam upgrade for £1200 but when you ring pretend it's not for an aircraft or Ross Pullen refuses to supply

    Ace reduction drive is a bargain too, Brit Hover have some left over big carbs from converting 990cc units and they perk up 630cc engines nicely, at half price

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