Pre Rotators

[asra]

Thanks Tim. My friend Alex is with you Doc, he reckons that with the soft start advantages of the carbon piles we can use small motors e.g. off motorbikes or lawn mowers and still get the 100 odd rrpms required. I think it is a simmilar situation to race bikes where the aim is to reduce un-sprung weight. i.e the wheels brake disks/calipers etc. Much has been done to reduce this as in upside down fork suspension systems. Once I was asked to pick up a Ducatti 916 rear wheel and tyre in a bike shop, nearly threw it over my head it was that light! Reduce the weight in the rotor system= less vibes maby? More food for thaught.Cam

[asra]

Telf......got some blue singlets for you, you be just like the rest of us........welcome home[^]Russ....A1014 NT....gods country

[asra]

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[telf]

Thanks Russ.5 more weeks in Alice, 5 weeks on holidays in Europe (tough, I know, but someone has to) then drive north......damn, I'll have to find a job when I get there.......Flying - The knack lies in learning how to throw yourself at the ground and miss. (Douglas Adams-The Hitch-Hiker's Guide to the Galaxy)

[asra]

Thanks Phil, I don't have any picture for Telf, I was going to take some tomorrow.As you can see I used bicycle parts ( just like the Wrights ), and yes, a lot of the bits were found during a council cleanup. Freewheel sprockets were of particular interest, despite some of the ones I found being rusty all 'freewheeled' and none failed to drive. Of course I used new ones on the gyro, 3 altogether, so that all 3 would have to stop freewheeling before I would have a problem, and even then 2 of them can simply spin off their threads. I mounted them on bicycle hubs which were heavily modified.The starter I used came off a Yamaha XS1100 and is rated at 500 watts = 2/3 Hp. I recently noticed that the starter on my K100 BMW is said to be 1 Hp.These starters need a 10:1 reduction, so I had to use a layshaft, which brings with it the problem of clearance with the pitch blocks on my 24" hub bar, the chainwheel on the layshaft is actually nudged by the pitch block with teeter full forward and to the right.I also had to fabricate a special torque tube.Please don't try this unless you have access to significant engineering facilities.Is it worth the hassle? I think it is, but then I am a stubborn old retiree who likes doing things differently.( aka "silly old fart")John EvansThink logically and do things well, think laterally and do things better.

[asra]

[asra]

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[asra]

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[asra]

Image Insert: 16.86 KBHere you are Telf, I took some pictures and Welly put them on, that's a first![]I'll have to revise my claim of getting 120 rpm,there was wind when I did that but I thought I had prevented it contributing, today with pretty calm conditions it only went to 95.John EvansThink logically and do things well, think laterally and do things better.

[telf]

thanks DocFlying - The knack lies in learning how to throw yourself at the ground and miss. (Douglas Adams-The Hitch-Hiker's Guide to the Galaxy)

[asra]

Hands up as to whomb can do this job better than the Doc.Surely I don't have to re invent the wheel here!!I dont look forward to looking up and seeing all that stuff hanging off my head. Bit like a prolapsed butt.The drill press is warmed up I just don't know where to drill the torque tube. Any help out there??Cam.-FYI- Crocodiles cannot stick their tongs out.

[asra]

Camel,Shame about them crocadiles not being able to stick their tongues out... would make it interesting if they were able to bite their tongues when feeding wouldn't it?Ted

[asra]

quote:Originally posted by camelThanks Sam and Ding. Will call Rosco next week.I have a LAME mate who has lent me a reostat-he calls them a carbon pile. He sais that you can initiate a very controllable pre-rotation- totally removing the "snap" by having a seperate circuit engage the starter solenoid and then use the seperate carbon pile controlled power input to slowly introduce the power for prerotation. Simply putting finger pressure on the pile feeds in more "power"(im pretty vague on the lingo of electricians)and thus a soft controllable start right to full spin up. Maby even using a smaller still ring gear.CamThere is at least one other way to soft-start a DC motor and I think it would be lighter in weight than a suitably sized Carbon Pile. The Carbon Pile to handle that sort of power would be huge and heavy, whereas a bit of simple electronics would be much lighter, would not waste power as heat and for less than an extra twenty dollars could be kitted out with microcomputer chip control to avoid over-torque, over-heating and other problems. For comparison, a carbon pile to regulate a small genemotor set of 200 watts weighed about a kilogram. I can't remember what the field current of a starter motor is, but it's certainly more than 200 watts, perhaps as much as 3600. The carbon pile would have to be sized proportionately. Electronics, I estimate, to do the job would weigh in at around 1.5 kilos. If any one is interested, get back to me.R.J.W.S.

[asra]

I'm entirely new to gyros and I've never laid eyes on one, but how would a truck compressed-air starter go as a prerotator? Would it be small/light enough? How big a tank would you need for the air?R.J.W.S.

[telf]

Not really feasible.One of the biggest issues with gyros is weight.The tank would be a big weight penalty, you would need to keep it charged up.All in all, there are much lighter ways.That said, its good to see a new idea being thrown around.We are all open to suggestions.Flying - The knack lies in learning how to throw yourself at the ground and miss. (Douglas Adams-The Hitch-Hiker's Guide to the Galaxy)