kitsune

[kitsune]

Where abouts?
Hopefully I can make it, otherwise I’ll be jumping off a cliff 🙂 (abseiling)

[kitsune]

Cool 🙂
There’s a meet on next weekend?

[kitsune]

I don’t think you can really waterproof a rc car without compromising on it’s performance, but you can make it splash resistant,

Get a balloon cut off the hose end used to inflate it, also cut a small slit in the opposite end.

Remove the formt wheels, knuckles and kingpins, Pull the balloon over the front of the car so it’s past the servo arms. (both the hole and the slit)
Reassemble the steering.

tape the balloon to the chassis just behind the servo arms.

remove the antenna + Hplate from the car

Pull the rest of the balloon over the car.
the motor wires should be sticking out ot the hole in the end of the balloon.

spread out a patch of CA glue or Arydite on the surface of the balloon where the hplate and the antenna are going to be bolted to the chassis, (this should stop the baloon from tearing once you put holes in it.

let the glue dry, then make some slots where the screws will need to go through.

screw the hplate and antenna back in place.

Tape up the hole where the motor wiresare running out.

Coat the arms ot the steering rack with vasaline or some other type of grease to repell water and reduce the chance of it entering the body there.

that should protect your batteries and electronics a bit better, if they get wet remove the batteries, wash parts with distilled/purified/deionised water (depending on what’s at hand, and alow to dry in a warm dry place for several days.

Hope this helps.

EDIT – that’s the prob with long posts someone beats you too it, the silicone idea might work well if there are no heat issues, but it might be worth putting the pcb in a condom and then just sealing it where the wires come out if all you want to do is protect the pcb wotherwise if you want to work on it the silicon can be a nuicence.

Edited by – kitsune on 24 July 2004 23:42:29

[kitsune]

Yeah Kyosho may consider it a mini,but its much closer to a 1:10 in scale and over twice as large as a mini-z/iwaver.

As for the TL01 – ROFLAMO Me too:)

[kitsune]

Update: prototype lower deck is almost ready, I’ve had to add a mini-lower deck on top of the main lower deck at the front to lift the servo so there’s enough room for the batteries and so that the front suspension will have room to move, while doing this I’ve worked out a way to give the chassis adjustable castor. I still need to drill hooles and thred them for the H-plate and glue the batteries in place,

Still need to make these parts …
Front upper deck, which will need to be adjustable for the castor to work properly.

Upper rear deck to mount the reciever on.

Mounting points for the shell

(and wire it all up + test)

so some progress made and quite a bit to still do.

[kitsune]

at 1:12, why not just go all the way and go 1:10 there seems to be a lot of support + clubs for 1:10, me – I prefer the smaller scales 🙂

[kitsune]

What did you get?

[kitsune]

I haven’t tried either, I’ve heard that the kyosho is the best out there, but is the best worth the extra? I don’t know. If possible find out from someone who has had experience with both, it’s easy to find people who will reccomend one product over the other without having tried both (heck I just did that 🙂 try to get impartial advice.

[kitsune]

Thanks for the advice
I think you’re right about the plates approach, I need to work out how to fit the shell on, but that ccan wait untill I get the hing to the point where I can drive it.
Also as you advise I’m planning to use the H plate to attach the rear – not gonna mess with that at the mo.
unfortunately I’m gonna have to flip the servo box or whatever you want to acll it over otherwise there won’t be room for the batteries.

[kitsune]

The switch can be removed from the chassis and the wires that connect to it are not soldered to the battery contacts, they are held against them using a plastic ‘plate’ that is screwed into place.

[kitsune]

From memory Ni-Cad batteries have a sharper voltage drop once they peak than Ni-MH batteries … so Ni-Cad Chargers may not notice that a NiMH battery has peaked because they arn’t looking for such a small voltage drop – consequently Ni-Cad chargers may overcharge (ruin) Ni-MH batteries.

[kitsune]

Quote:

TD, good web site. If we buy one of those VS-40 (8 ft by 6 ft) $80 USD tracks “each” we could simply join them at the meet and have a decent track. At the end of the day, simply disassemble and take your part of the track home. RCP track Wide-L $200 USD (9ft by 12ft).

Say if you bought two VS-40’s it would still work out cheaper at $160 USD with (16ft x 12ft ?) driving surface.

Ahh 8ft x 6ft x 2 = 8ft x 12ft
almost as big as the RCP 9ft x 12ft
but as you say you can then split it between two people

[kitsune]

I’m not saying Powertech cells are better or worse than GPs or SANYOs, I’m just saying that production standards may have improved to the point that Powertech feel that the batteries can consistently provide 900 mAh and so may have decided to label the batteries accordingly (for market advantage),

I have heard that one trade off for high mAh ratings is an increased internal resistance, so ironicly 600mAh batteries may actually be better for racing than 800mAh or 900mAh even if made by the same manufacturer.

Which battery is best WILL vary from car to car, unless your car can take advantage of the entire discharge rate of the batteries higher discharge rates will not help, but longer mAh ratings might as the batteries may take longer to fade, if the car can take more power than the batteries can push, then discharge rate may be more important than mAh rating.

I don’t know which are best, but I’d advise when you meet someone who is using batteries from a different brand to yours rather than telling them that they are bad batteries and getting into a P!$$!ng contest ask if they are willing to swap a charged set with you for a stint so you both can compare how your cars perform with different batteries, at worst you prove your point that yours are better, at best you find a way to improve your car, and either way chances are you’ve made a friend.

[kitsune]

I’ve had a look at how the Iwaver’s wired up and If I’d designed it I’d be ashamed, then again I tend to belive in there not being such a thing as too much over kill 🙂 I don’t know how the mini-z compares but I’m planing to re do the whole thing. firstly to get rid of the poor contacts with the batteries I’ll build some battery packs using tagged 800mAh NiMH batteries and get rid of the contacts used in the Iwaver, Mini power connectors will connect the batteries to the rest of the car’s electronics (using heavier guage wire too) via a plug in connector, wanna turn the car off – unplug the battery pack, yep it means I’ll have to use a multi cell charger rather than a standard one, but I can live with that. (might even use it as an excuse to go to 5 cells) the connector that the battery pack will plug into will run two sets of the thick wire, one to the PCB and the other to what ever fets I use to control the motor then more thick wire directly to the motor.

so to look at a summary of changes
out goes the metal against metal contacts at the batteries and on the wires running to the switch – replaced by soldered joins

out goes the switch with who knows how low a Amp rating to be replaced with a connector rating unknown but should be much better than the switch.

out goes the thin wire that breaks all to often near the joins to be replaced with thicker lower resistance wire.

now all I need is a good set of fets and I’ll be able to take advantage of this upgrade.

[kitsune]

If you’re talking about the interlocking rubber squares with guard rails take a look at clarks rubber I think they sell the mats, then you just need to make and attach your own rails, If it’s the same stuff it might be cheaper than buying a complete one.

^{edit: typo fix}

Edited by – kitsune on 20 July 2004 20:58:29

[kitsune]

I’ve given up on the spacers and started using cardboard + paper to fine tune the position of the motor.

[kitsune]

Look and see if they still have stock of the 800’s if they do chances are they won’t get the 900’s in untill the 800’s are gon, they’ll be hard to shift once the 900’s are on the shelf, check the prices too, they might be getting rid of the 800’s at a good price. (IMHO the 900’s will probably be the same as the 800s, QC has probably improved and now they feel they can claim a higher mAh rating – I’ve got no proof but you might find little difference between recent 800s and the new 900s)

[kitsune]

There’s some tennis courts on the right hand side of Dorset Rd just after the Boronia Road intersection, Its used by the Boronia club (can’t remember their full name) they use it for 1:10 races Wednesday nights, but i’ve seen others use it on the weekend for practice, we wouldn’t have exclusive access, but given the speeds you guys have been quoting I would love to see how the 1:28’s measure up to the 1:10’s.

Edited by – kitsune on 21 July 2004 09:02:34

[kitsune]

Try local factories – on weekends often there’s empty car parks, if you can find a concrete one that should do nicely as for the track, you could put down tape to mark the track (as long as you remove it, and are willing to spend the money) you could use garden hose, (might have to tape it in place, but could do the job nicely particularly if you’re willing to cut some shorter lengths. Or there might be other better solutions others can suggest. If you’re using an unused car park you might want to block the entrance with one of your own cars (with a note telling people why and that if asked you’ll happily move it)

I don’t know the exact legalities of using those shared concrete car parks, but as a out dor venue it might do the job.

[kitsune]

Kenworth? Along Canterbury Road?
How about now, Hopefully not too far.
How about everyone else?
(Boronia would be mor convinient for me, but perhaps templestowe is best for everyone else)

[kitsune]

Great 🙂

Not much of a driver,
Dunno much about setting up the cars,
But love messing with the electrics 🙂
And always willing to learn.

(Live in Heathmont, Work in Croydon.)

[kitsune]

Any plans to do this again in the near future?

[kitsune]

ph2t – thanks for the detailed response.
are you going to be doing an order with digikey in the near future? if so would you be interested in adding some bits on for me and I’ll chip in towards shipping?
How goes the search for even better fets?
If the newer mosfets are useable could you let me in on their part numbers, Digikey out of stock of the IRF7425 – and looks like they will be for over a month.

[kitsune]

The only problem I can see there is diminishing returns.

After all making aperfect turbo won’t change the resistance in the motor, wires, battery contacts and the batteries themselves, now will it allow the battery to push more than it’s capable of, to get an idea of the maximum speed a car is capable of with the existing motor + gearing etc hook up the batteries directly to the motor, (If anyone does this I’d love to know the results) and run it on a dyno + compare to when the speed’s being regulated by a turbo or the onboard fets. (ok dyno results arn’t entirely accurate but they give a feel for the situation.

I’d relly be interested in the top dyno speeds of a) the same car with standard fets,
b) the same car with Nelly,
c) the same car with a stacked Nelly,
d) the same car with the batteries tied in directly to the motor,

even if we can’t get figures on a stacked nelly the other figures would be interesting to see how much of the car’s potential you can reach with Nelly.

You could even use a formula such as

(rating)=(nelly speed boost)/(Potential speed boost)
(Rating)=(b-a)/(d-a)

(you could sub other turbos etc to get rating for other options)

(the following is using imaginary figures)
eg. if a car with stock fets goes 15kph (a)
and It’ll go 35kph with a nelly (b)
and with the batteries hooked directly to the motor goes 45kph (d) its rating would be …

rating = (b-a)/(d-a)
rating = (35-15)/(45-15)
rating = 20/30
rating = .6666 (or 2/3)

so on that car nelly would provide 66% of the potential speed increase that the car is capable with those parts in it. (roughly ther’s some minor details that I’m leaving out such as power drain from the controller etc.

Thoughts? Results?

[kitsune]

Lorenz’s Law of Mechanical Repair: After your hands become coated with grease, your nose will begin to itch.

(Or do you mean Lorenz force Law?) 🙂

If the power to the motor is pulsed a larger cap across the wires to the motor would smooth out the pawer and cause it to run smoother – less arcing from the brushes (which causes interference to the radio signals controlling the car) shortens their life span, and causes pitting which increases their electrical resistance when it come to pushing power to the com – all bad things. plus the car might run faster because during the non pulse moments the motor isn’t acting as a generator.

if as you say its voltage regulated then all the caps gonna do is slow down the responsiveness of the motor (kinda like having a spring on your accellerator pedal, takes longer to react to accelleration + decelleration)

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