light component suggestions

Dan · Post by **Dan** » Mon May 07, 2007 11:17 am

ok ive finished the cover and everything now i have to lose around 60g grams any suggestions on 4.8-6v batteries (cheap please)

peterwaller · Post by **peterwaller** » Mon May 07, 2007 11:27 am

If you wan't to lose weight then you need to go to lithium polymer but one cell is 4.2v and 2 cells 8.4v so you cant get between 4.8 and 6. There are other problems like you need special chargers and have to be very carful when charging and discharging them otherwise they can be easily damaged and in some cases catch fire. If you are young it is probably best to ensure your parents read up on them to see if they are happy about you using them. Also if you go for 8.4v you will need a regulator to lower the voltage for the receiver and servo's if you are using them. I see you are in Milton Kenyes if you can get to the roaming robots event in Aylesbury next Sunday you could have a look at some other ants and show us what you have so far.

Post by **BeligerAnt** » Mon May 07, 2007 11:37 am

Unfortunately 60g is a lot to lose! It's about 1/4 of your total weight.

Start by considering the heaviest parts and see how much weight you can save from them. The cheapest weight-loss plan is to remove material from parts you already have, although this may not be enough to save you 60g.

Remove the receiver case, especially if it's a moulded plastic one.

Drill holes in the chassis and any structural parts. Don't go too mad, you still need some strength left, but you might be able to remove 50% of the material and still keep most of the stength. However, if your chassis is only 20g to start with, you will not be able to lose much weight no mater how hard you try.

Use a smaller battery pack. You don't need more than about 300mAh capacity. If you're using AA's or even AAA's you will have weight problems.

Check the weight of your wheels. Lego and model aircraft wheels are good but heavy. Try making your own or find some with lightweight foam tyres instead of solid rubber. You can add Dycem to give good grip.

If you still have trouble getting to 150g, post a list of the weights of each component and we can concentrate on where the worst problems are.

Dan · Post by **Dan** » Mon May 07, 2007 5:43 pm

ok heres what my bot is made of:

a wire mesh shell
polycarb chassis and wheels
some aluminium angle bracket
4 AAA batteries
acoms ar-2 receiver
2 hs55 servos
mixer
switch

hope that helps
you guys are going to Alesbury RR?

peterwaller · Post by **peterwaller** » Mon May 07, 2007 6:33 pm

As Gary says we really need the weight of the parts to know where the problem is. The batteries are an obvious start as I said earlier and as you are using a two channel Rx I guess there is no weapon so power requirements are low. I have just weighed some AAA cells and they come out to 44.4gms for a 4 cell pack.
You can get NiMh rechargeables that are smaller.
2/3AAA 300mAh 29.4gms
1/3AAA 110mAh 14.8gms
Lithium Polymer
220mAh 15gms
110mAh 8.8gms
If the wire mess is steel that can be heavy as can a polycarb chassis depending on the thickness.
Acoms receivers are often quite heavy but you can get hitech feathers at about 8 gms and some others as low as 4gms.
Many people do without the mixer using the transmitter stick on the diagonal.
I believe we are attending the Aylesbury RR event although it does seem to have gone a bit quite check the events section.

Simon Windisch · Post by **Simon Windisch** » Mon May 07, 2007 7:57 pm

Yes, let's do Aylesbury, the table will be there for us, although I was hoping for some more people there...

You can lose the switch, most people define a battery plug as the removable link that the rules require.

Simon

Post by **BeligerAnt** » Wed May 09, 2007 8:18 pm

Suggestions:
Use smaller batteries
Lose the receiver case
Lose the mixer
Drill holes in the chassis and angle bracket (use thinner material?)
Drill holes in the wheels or make lighter ones
Check the weight of the shell, this could be your problem area.

Note you can only lose the switch and rely on the battery plug if it is easily accessible. If you have a standard R/C model switch, lose the plastic case.

There's no point in trying to save weight with the servos, they are not your problem area.

Dan · Post by **Dan** » Tue May 15, 2007 6:31 am

yeah im hopefully going to the alsbury one maybe you guys could show then?

leo-rcc · Post by **leo-rcc** » Tue May 15, 2007 7:15 am

Correct me if im wrong, but Aylesbury was 2 days ago?

Simon Windisch · Post by **Simon Windisch** » Tue May 15, 2007 11:55 am

It sure was.

Simon