custom-vince Posted February 12, 2016 Share Posted February 12, 2016 There's always been the big discussion of which is best and why. Conclusion is always personal choice. I want to explore the idea of a new style drive. Gearbox but without clutch and without double spring starter. It would work and feel like a direct reduction belt drive. Why? I'm not a clutch fan, but not against gearbox reduction. Are there any pilots who would welcome a design like this? No belt wear, no clutch wear. Quote Link to comment Share on other sites More sharing options...
Guest Posted February 13, 2016 Share Posted February 13, 2016 The idea makes some sense for sure. The good thing about belts and clutches as that if you do have tumble on take off, there is normally enough give in either the belt or the clutch to avoid snapping your crank. SW Quote Link to comment Share on other sites More sharing options...
cas_whitmore Posted February 13, 2016 Share Posted February 13, 2016 Could you test the idea on clutch motor ' with the clutch locked up just to see how it feels . Cas . Quote Link to comment Share on other sites More sharing options...
custom-vince Posted February 14, 2016 Author Share Posted February 14, 2016 You could but I have 2 belt drive machines. Lol. I'm more seeking advice on pit falls or if it's just not wanted. SW has a good point about impact, the a clutch or belt even engaged would slip a bit during an accident. Replacing a prop is bad enough, replacing a prop and mechanical parts would be worse. A safeguard would need to be built in. Quote Link to comment Share on other sites More sharing options...
cas_whitmore Posted February 14, 2016 Share Posted February 14, 2016 Folding prop type of thing perhaps , might take the sting out of the torque effect . Quote Link to comment Share on other sites More sharing options...
ptwizz Posted February 24, 2016 Share Posted February 24, 2016 Apologies in advance if I'm pointing out the bleedin' obvious: A possible concern would be the oscillating loads on the gearbox at low rpm. The propeller is a large flywheel. The engine makes all its power during the combustion cycle, and accelerates the crank for that part of its rotation. During the rest of the rotation, the crank slows. Thus the engine exhibits 'torsional vibration'. This is most noticeable at low RPM. A centrifuge clutch provides torque transmission proportional to rpm, so it can disengage or slip at low rpm (when the engine rotation contains significant torsional vibration) and prevent the load reversals which would be seen at the gearbox in a rigid drive setup. A torsional shock absorber between the crankshaft and the gearbox would reduce the effect. Quote Link to comment Share on other sites More sharing options...
Guest Posted February 24, 2016 Share Posted February 24, 2016 I think the C42 has a 'soft start' option which is basically a torsion fitting somewhere in the system so that does make some sense. SW Quote Link to comment Share on other sites More sharing options...
custom-vince Posted February 24, 2016 Author Share Posted February 24, 2016 I did wonder about this, you explained it perfectly. I think it would knacker it pretty quickly. Quote Link to comment Share on other sites More sharing options...
cas_whitmore Posted February 27, 2016 Share Posted February 27, 2016 Thing is Vince until someone shows you a box of broken bits . It isn't obvious. I'd give it a go , rig something up start it and walk away until it brakes or runs out of fuel . Then you'll obviously know . Cas . Quote Link to comment Share on other sites More sharing options...
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