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General control line discussion => Open Forum => Topic started by: Mike Griffin on January 17, 2012, 05:57:14 PM
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What changes in design or balance (if any) have to be made in order to convert a tail dragger model to a tricycle gear? I am not talking about mounting the gear in the wing and adding a nose wheel. What I am wondering if there are any technical considerations you have to take into consideration to make the change or can any model be converted.
Thank you
Mike
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In general just go for it, the airplane won't care. Like you've mentioned, the only real difference is the L/G placement. Putting the main gear axle roughly 15 degrees behind the airplanes airfoil C/G is a good general reference point.
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Two main considerations are deck angle and the direction of travel for the nose gear. You will want the airplane to sit at a slightly nose down angle on level ground. This allows you to fly the airplane off the ground. You will also want the nose gear to turn with the circle. This keeps the plane from turning out and trying to drag the nose dear off and possibly flip the plane on it's nose and inboard wing. Once set up properly they are a dream to takeoff and land.
Weight shift is a different animal. Moving the mains aft, the tail wheel is eliminated and a nose gear added. With the load shift changes, they nearly cancel each other out. The lighter tail wheel assembly is much farther aft than the heavier nose gear assembly, whicch has a shorter moment arm.
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No thoughts on the extra aerodynamic drag from having 3 main wheels instead of two and the downwards vertical CG shift from doing the same?
I have only flown one trike gear model before and it seemed to me that the added front wheel was indeed heavier than the loss of the tail wheel, and the over all model simply gained weight.
But I can't state a trend through only having flown one!
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Doing a trike from a taildragger is pretty simple as those have already stated, but the issue of a new vertical CG is utmost on my mind,
BIG Bear
RNMM/AMM
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Two main considerations are deck angle and the direction of travel for the nose gear. You will want the airplane to sit at a slightly nose down angle on level ground.
I know that Bob Baron said never have a negative angle as the plane will be almost impossible to rotate, some one else said the very same thing. I could be wrong, often am.
Walter n1
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You might be persuaded by the fact that Paul Walker's current model is a trike, and electric to boot. The Shark 45 is maybe the most successful trike I can think of. While I don't at all discount your point about aerodynamics it appears not to be a disqualifying factor as far as design and performance are concerned.
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I like Zuriels comment about the weight shift and cancellation between taildraggers and trikes, never gave it that much thought but it makes sense.
In general though and having done it, unless you're planning to be World Champ I'll still say the vertical C/G isn't a huge deal, just don't use lead wheels. ;D
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You might be persuaded by the fact that Paul Walker's current model is a trike, and electric to boot. The Shark 45 is maybe the most successful trike I can think of. While I don't at all discount your point about aerodynamics it appears not to be a disqualifying factor as far as design and performance are concerned.
Probably because you don't need a stooge with an electric.
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Probably because you don't need a stooge with an electric.
Actually I think you will find that most people who are smart and safety aware will still use a stooge even with electric.
and just for the record, my stooge works just fine with trike gear,,
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Actually I think you will find that most people who are smart and safety aware will still use a stooge even with electric.
and just for the record, my stooge works just fine with trike gear,,
You might be right but I'm sure that if we start a thread on stooge accidents we might get a couple of hits (no pun intended).
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When I built the Latency I set it up so I could go either way by simply swapping the main gear from side to side and bolting on a tail wheel. Once I started flying it as a trike I never looked back. It's almost like cheating, you can hold it on the ground as long as you want and AMA take offs are a piece of cake. When it lands it's like the wheels have sticky paper on them, it can be bounced but you have to really screw up the landing to do it.
Not sure I'll ever have another PA airplane that's a tail dragger.
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I suggest just taking a proven tricycle gear design such an RSM Shark 35 and using it as a template for your conversion. Pat Johnston did a great job re-engineering the nose wheel installation on that one. 8)
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Two main considerations are deck angle and the direction of travel for the nose gear. You will want the airplane to sit at a slightly nose down angle on level ground.
I know that Bob Baron said never have a negative angle as the plane will be almost impossible to rotate, some one else said the very same thing. I could be wrong, often am.
Walter n1
I got my information from a pretty good source and it worked very well. Check out Mr. Fanchers response.
http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=31114&mesg_id=31114&listing_type=search