Overview

[aero_storm]

This forum is great! I have learnt more from this forum in the last two days than all of my research! Thanks for the link Woody (Did you build onslaught?). If I was to use four of these
http://www.argos.co.uk/static/Product/partNumber/7104899/Trail/searchtext%3EDRILLS.htmhttp://www.argos.co.uk/static/Produc...rchtext%3EDRIL LS.htm
would that be O.K?

So that I can work out what wheels I am going to use please can I have a formula for a) RPM to speed with x sized wheels and b) A formula for torque.

Thanks a lot you lot,

Alex R

[beast]

beauty likes the £10 ones they are cheaper

(make sure the wheels are on tight they fall off !!!) i h8 them girly robot drivers

[widow_twanky]

Locktite is also good for the wheels it is rather embaressing when someone asks you to drive to the middle of the arena and the wheel unscrews iteslf before you get there!!

Andy

[woody]

Hi Alex R,

Yes Onslaught is my old bot.

Links:-

http://www.4qd.co.uk/faq/roadspd.htmlhttp://www.4qd.co.uk/faq/roadspd.html

http://www.teamkiss.com/builder.htmhttp://www.teamkiss.com/builder.htm

http://architeuthis-dux.org/torquecalc.asphttp://architeuthis-dux.org/torquecalc.asp
Pick a Harbour Freight Drill as your drive.

Woody

[aero_storm]

So what wheels should I use?
About what diametere with a 550RPM drill?

Thanks for the links.

Alex R

[woody]

Alex R.
Take the http://architeuthis-dux.org/torquecalc.asphttp://architeuthis-dux.org/torquecalc.asp link

Pick the Harbour Freight 9.6v Drill

Youll see a box with :-
Voltage Constant[ ] RPM/volt simply divide the drills rpm by the voltage 550/9.6 = 57.29 and input this number into the box... Its actually pretty close as it is ... 55.6 x 9.6 = 534 rpm

Pick 30lb bot... 6 wheel... 1:1 Ratio and 2 motors per side ( 4 wheels driven )

Play about and alter the parameters of voltage ... wheel dia and number of motors per side.
E.G. 12v instead of 9.6v and 5 instead of 6 wheels etc ...

Note the changes ouput by the calculator....

It even gives an estimation of the required battery pack Ah.
The biggest problem with drill motors is IMO is the Stall Amperage ...Speed controllers can cut in and out if they have current limiting.

(Message edited by woody on October 08, 200

[geoff]

Thats a very handy calculator you found there Woody! Nice one!

[aero_storm]

Erk.... Thats quite slow....I was lookin more in the region of 20 MPH rather than 9. Is there anything I can do to solve this?

thanks

Alex

[woody]

DOH!....courier newcourier>I said +1>PLAY with the numbers.

Try.
BIGGER WHEELS!
OR
A faster donor drill or try overvolting by say 50% max.

[aero_storm]

I knew that. If I overvolt it wont I overheat it? I think Ill have to look for new drills, Im not prepared to use larger wheels. If I overvolt it by 50% will I get 50% faster rpm? And are there any faster drills anywhere?
Links please.

Thanks you

Alex