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General control line discussion => Open Forum => Topic started by: John Leidle on November 14, 2014, 05:52:15 PM
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I wonder what would happen if an Electric prop was put on an IC engine , would it come apart?
John
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More than likely , yes. There have been electric props that have come apart on electric motors also!
Type at you later,
Dan McEntee
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I vaguely remember an individual who used electric props on his IC planes. At a contest he was not allowed to fly the combination in competition because some people claimed the IC engine destroyed electric props. In fact I beleive the people even went to the then technical director about the situation and his response was, "No electric props were to be used on IC engines because of the pulses of the IC engine compared to an electroc motor". I myself have never seen one in use on a IC engine so I can't say if they are safe or not.
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I wonder what would happen if an Electric prop was put on an IC engine , would it come apart?
John
Look at this thread, you will see the likely problem:
http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=333912&mesg_id=333912
What that is telling you is that the torque varies greatly during a rotation. I think that the electric props are probably fine for a constant RPM and the maneuvering we are seeing, but will whip back and forth "in plane" violently as the torque accelerates the hub and the blade follows. People have done run electric props and they stayed together but I wouldn't recommend it.
Brett
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Thanks everyone.
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John, are you considering wood, plastic, or CF electro props? CF is ok. I wouldn't use the other materials. The Dreaded Canadian Propeller Factory says their props are ok for IC engines. But you want the RH props, 'cause the LH ones don't give the right lap time... LL~ Steve
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Steve , I'm considering props lighter than APCs which includes most everything. How's the new build coming along? I'm doing fillets on my new one... if you could use some glue to speed yours up I'll swing by & drop some off.
Went to the hobby shop today & ordered some fuel... a bit cool to fly so I'm finding excuses not to go... D>K
John
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John, are you considering wood, plastic, or CF electro props? CF is ok. I wouldn't use the other materials. The Dreaded Canadian Propeller Factory says their props are ok for IC engines. But you want the RH props, 'cause the LH ones don't give the right lap time... LL~ Steve
A key difference between the Chris Cox props and the others is that they have substantial material around the hubs like a conventional prop. The problem with any of these sorts of evaluation is that no one has clearly defined an "electric prop" and they aren't all the same by any stretch of the imagination. There's no way I would use an APC Electric prop, or any of the quadcopter props I have seen. But that doesn't mean that safe ones don't exist somewhere.
Brett
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John, are you considering wood, plastic, or CF electro props? CF is ok.
Some of them are, some of them not. Our newest hollowed CF props are not, they are only electric.
http://www.maxbee.net/props/props.htm
However I know there are also hollowed props for IC with little different construction of hub, so it is always good to check. I think Mejzlik makes them, but much larger diameters then we use.
In any case usage of electric props on IC is not good idea, but it does not mean that all electric props are safe on our stunters, I remember that long use of old APC props (before redesign with thicker root) did visible slowly growing cracks because of vibration in corners. Designers probbly did not count with such effects during flight. R/C guys do not routinely fly tight corners.
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I have used a Xoar 13x6 Electric prop on my Saito .56 4-stroke for quite some time now. and also a CF Majelik 11x5.5 copy 3-blade E-prop repitched on a piped .40VF as well. :) But not all electric prop are safe to use. only if the hub to blade are strong enough to handle pulses. and best not to have to flip by hand.. either use a starter or bump off the compression to start. and check prop frequently.
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I ran an APC E10x5 or 6 on a Fox .35/Ruffy without a problem.