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Prop Design (designed in safety)


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I have seen a bloke loose a finger with a 60 size heli (10.5cc) when he caught the rotor slowing the head down, those blades were just off the motor chop so inertia only and knocked his hand right out of the way, they were still spinning and his finger was held on with a bit of skin only. if it was under power would prob took the lot off.. you are not going to benefit anything on the safety side, poss only if the hub was made and it reduced the cost to buy spare blades as chances are you would only break 1 blade.

downside the hub will add weight to the paramotor as would have to be machined out of solid billet aluminium, then pivot bolts and bearings also the extra cost to do this and all the safety testing etc..not worth the hassle. forget it

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its good to look outside the ( Box )..sometimes..Albert Einstein is the best example of this :?

Thats what I am talking about :D

A winners attitude that is!

SW :D

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It will still make a mess of anything that's soft like flesh but if the prop hit something hard like the ground or the cage the prop would swing in instead of disintegrating, like the RC Heli blades! Similar to the strimmer hitting a rock as Simon said, when it hits the soft grass the grass gets cut but when it hits a rock the strimmer blades fold in, am I right or am I right :)

Richard X

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What is this idea that RC helicopter blades don't break when they hit the ground, mine always smash into matchwood!.

As the famous Chief engineer Montgomery Scott (Scotty from Star Trek) said 'you cannae change the Laws of Physics Richard X'

Cheers

Eddie

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As I say...

in the middle of something else at the moment but I recon its worth a prototype build and test for the tube. :-)

My thinking at the moment is something along the lines of

the bearing closer to the tip, and the tip made of some hard casting rubber (which is easy to do and I have it already)

Back burner for now...

Great conversation though :-)

SW :D

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What is this idea that RC helicopter blades don't break when they hit the ground, mine always smash into matchwood!.

As the famous Chief engineer Montgomery Scott (Scotty from Star Trek) said 'you cannae change the Laws of Physics Richard X'

Cheers

Eddie

Hi Eddie, I've only every broke one prop on an RC Heli and that's because I'd tightened it up too tight, other wise if they every went over on one side the prop would hinge in and then the clutch would kick in and the prop stops turning.

This one needs a bit more thought and a few prototypes but I can't see a problem with scaling up the RC idea.

RDX

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This is beginning to sound like a nightmare version of Alice in Wonderland.

please can we bin the idea. I fear for the safety of anyone within 50 metres of one of these folding props whilst spinning, nevermind the poor sod who might be struck by one, because his cage and netting weren't adequate.

Dave

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This is beginning to sound like a nightmare version of Alice in Wonderland.

please can we bin the idea. I fear for the safety of anyone within 50 metres of one of these folding props whilst spinning, nevermind the poor sod who might be struck by one, because his cage and netting weren't adequate.

Dave

As long as safety is paramount then it needs to be tried, if you dont try things how do you know if they will work or not.

Imagine if cave men did as they were told

DONT rub those sticks together or you might get burnt :D

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Nice try Pete (I always like your sense of humour.)

1 If safety is paramount let's insist on adequate cages and netting. It might even be less costly. R and D for hinging props wont come cheap, even if it did reduce injury, which it wont. Better frames will though

2 We've evolved a fair bit since cavemen (even you !) He didn't really have anyone more knowledgable to warn him. He had to find out. We owe him

Do I really have to explain, in detail, why it is flawed ? Most people here know it already. I'm sure your finger's poised to write and tell me that " Neccessity is the mother of invention" ..... see 1 above

DG :D

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Well I dont think it will work either due to the rotating mass of even a small light weight tip but that wouldn't stop me

from trying it, just to see what it could possibly lead to. Probably nothing except a hole in the roof of my garage :lol:

Full suit of armour on and ready to go :shock::D

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Dave,

I can assure you 100% that if you knew what the current project was, you would be more worried. We are big boys with toys.

Even in my bike days, I could never bring myself to buy a bike from a bike shop, I would sooner pull a frame out of someone's hedge and build a bike around it....

I do of course understand that there are many (most) people who will just never 'try stuff in there garage' but that ain't me.

As far as I see it, if the mass is less, the pain / impact / force will be less, each to there own I say.

As far as safety... give me some credit!! Its not like I am going to try in in a children's playground is it! We can all see that testing could be unsafe but it could also be safe (when they test war heads no one gets hurt)

The world is flat.

SW :D

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Point taken Simon. And I dont wish to be a kill-joy. But the science is simple and putting a pivot anywhere along the blade will not make an appreciable difference. It will certainly make no difference to the mass of the blade or it's speed and hence it's destructive ability will remain much the same. It might, momentarily, remove some of the torque of the engine but the flywheel effect of the prop will be the greater element and none of that will be reduced. I will give you credit for your idea but I hope you will give credit to established science, which wont be changing anytime soon ! I take this thread as a bit of fun. I dont feel it will be more usefull than that. Nothing personal either. Now go and build a really s**t hot paramotor that's high performance and safe. Then you'll truly have my attention.

Dave :D

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