Unless of course the builder has half a clue and builds a good bot...
Unless of course the builder has half a clue and builds a good bot...
Its Ed... think of your own ending to this sentance :P
regards
Dave moulds
Team Turbine
And Ed has quite a bit more than half a clue when it comes to spinning featherweights. As for big batteries, not really hugely necessary as the lem wont draw a huge amount once the disc is up to speed- a really efficient big motor like that will probably only need of the order of 5A once the disc is up to speed. Remember that (and this is fairly over simplified) if his disc has, say, a theoretical kinetic energy of 2kJ at its intended speed, and the lem is something around 3kW power, that means its 3 thousand joules per second, and the disc will only need 2 thousand joules of energy put into it. So youve got a motor providing 3000 joules per second trying to give 2 thousand joules of energy into a disc- so the disc will spin up very quickly. Once the disk is up at full speed, only frictional losses will dissipate its energy when its just spinning, so the LEM really has only to keep it topped up with enery- not a partiularly arduous task, so the lem wont be using that much power at all, therefore little current. The only 2 big factors I can see being a pain are simply the fact that LEMs are heavy by featherweight standards, and of course it has to be built stong enough to take the rather massive knocks, but in terms of batteries, they only have to be able to cope with the spin up. Once the disc is cruising, there shouldnt be a huge problem.
Well!
I have Just read through this thread and all I can say is we are all in the seriously deep poo if Ed gets this LEM powered spinner of his up and running.
I speak from 1st hand experience of building LEM powered spinners for heavyweights and that LEM130 is one SERIOUS motor! We use one to drive the disc on our heavy and it is a killer, (If you need evidence, ask Stu, He has seen it used in anger!) Now, if you put that sort of power into a feather the only problem I see is how the hell are you going to hold it down. If we assume that the motor weighs around 3.25Kg add say 3Kg for a disc plus 24V worth of battries, 1.3Kg in NmHI or 2Kg for Ni-Cad, then you need a drive system of some discription, maybe another 2Kg Thats around 9.5Kg, leaving 2.5Kg for a chassis capable of holding the impact from the disc and some armour (that last bit is hard enough in a heavy, let alone a feather!) Good luck Ed, I would love to see it!
Ewan, yes its possable to build a feather with a powerful, nimble and quick drive train plus a very respectable 4500 RPM 2.5 Kg vertical disc, we have! Mind you, to get it to drive anywhere near as good as we wanted took 4 years of heavyweight building experence and a top of the line programable Vantec speed controller! (Sorry, that makes an H5 look like a toy!) Even then we still have problems sometimes making tight turns with the disc at full chat due to the giroscopic effect. The whole machine can tip over at about 45 degrees before slowly comming back down! (you canna change the laws of physics Jim!!) The point Im to make here is that spinners be they heavy or feather weight are not as easy to get right as some people think, even a featherweight one can be leathal and I do mean LEATHAL if not properly built. I Have been in a workshop with a heavyweight robot when a blade weighing only about 1/2KG parted company with a disc spinning at 5000 RPM Fortunatly it landed inside the robot but the damage was horrendus and I was scared s**tless! So, to all you guys out there, keep building those spinners but PLEASE, PLEASE be careful and if in any doubt get it checked by someone who knows what they are looking at!
I wish everyone a very Happy New Year and productive but above all SAFE roboteering,
Geoff,
Team Scorpion.
Ok its time to put the cat among the pigeons.
When considering the rate of improvement in feathers, it is possible to envisage a need for 2 classes at some point in the future.
How about
Class 1. The bodgers
Class 2. The machine toolist/ contract the work out brigade.
Regards
Tim
Sorry, that makes an H5 look like a toy!
Actually the H5 runs rings around a Vantec in terms of handling - what do you think is at the heart of Storm II, H5 technology
Having used Vantecs for all our previous robots, H5 knocks the spots off it !
Ed
http://www.stormrobot.comhttp://www.stormrobot.com
Ok Ed, maybe that statment was a bit strong, sorry. But I like my Vantec!
In the interests of a fair comparison, please may I be really cheeky and ask if I can have a little drive of Storm II at some point?
That said, sorry Ed, but I still cant quite see how you are going to get that LEM in a feather!! But I admit I will be seriously impressed (and worried!)if you do!
Geoff.
There seem to be all sorts of rumors circulating regaring what were up to Geoff !
Suffice to say that I do have a spare LEM and nothing to do with it..... and I do have a CAD model of a LEM powered feather spinner though.
Ed
http://www.stormrobot.comhttp://www.stormrobot.com
im not scared..... ill fight anything !!!!!! you know me
My 160kw Truck motor powered at 8 million volts new feather will take anything on, yes its 12kg aswell.
And runs upside down, and is made of plactic, and also is painted pink.
CCCOOOMMMMMEEEE OOOONNNNN !
jonno
go jonno u big brave man u..
Bookmarks