Racing - R/C Cars
Kevin left a comment on one of my earlier posts about running in the Hyper 7, saying that he’d broken the steering servo in his and no one seems to stock Ho Bao servos. I had the same problem with mine, I stripped out the steering servo pretty early on after landing awkwardly off a jump. Anyway, I replied to Kevin’s comment in email, but thought I’d share my replay in case it helps anyone else…
In general terms servo’s (as used in cars anyway) come in two sizes. Standard and Mini. The mini servos are generally only used in smaller scale cars, like 1/12th and 1/18th scale. The Hyper 7 servo’s are standard size.
The other thing to look out for is the type of plug which goes into the receiver. Generally these are either a “Futaba” sttle which have a small tag on one end to stop you from plugging it in backwards, or “Sanwa” which doesn’t have a tag and instead has two chamfered corners. If you’re careful you can plug a Sanwa plug into a Futaba socket but there’s nothing to stop you from plugging it in the wrong way. Likewise, you can take to a Futaba plug with a knife and cut it to fit a Sanwa socket, I’ve done that myself and it works fine, but its really just easier to get the right plug.
The standard Ho Bao receiver has a Sanwa plug. In fact, I think the whole radio is just a re-badged Futaba unit, in which case, the servo’s that came with the car would most likely be rebarged Futaba S3001’s. According to Futaba’s web site they do sell gear sets for the servos, but given that you can buy the whole servo from most happy shops for around $30-$35 it may not be worth trying to fix. You don’t have to use Futaba servo’s either, any standard size servo with a Futaba plug would work fine. That said, the Hyper 7 is a heavy car and the plastic gears break pretty easily, so I wouldn’t replace it with cheap servo. You’ll break them too quickly and it’ll cost you more in the long run.
I replaced mine with a high speed, metal geared servo (Hitec 525MG). The high speed gives a bit quicker steering response, but the metal gears make the servo much more durable. Mine’s still going strong after 12 months. The only problem I had is the Hitec servo is a different size where the servo horn connects to the sero so you’ll need to adapt one of the servo horns that comes with the Hitec to fit rather then using the standard one.
I recently bought a set of 8 Energizer NiMH rechargables to run in my transmitter (the awsome Futaba 2PL). I didn’t buy the Energizer charger because I’ve got my Integy 16×5. I’ve had the Integy for a coupla years now and like it a lot. Its done an excelleny job of looking after my cheapo 3300 packs I use for racing, and I figured it’ll do a much better job of AA’s than some $20 charger from Bunnings.
Of course, that left me with one problem! Charging current… I know the AA’s and AAA’s are sensitive to charging current, you certainly don’t force feed ‘em at 5amps like you would a racing pack. But I didn’t necessarily want to charge them at 0.2 amps (the slowest rate the Integy can charge at) because it would take all day!
The Energizer site had a datasheet for my batteries, but it doesn’t mention what current to charge at (they probably want you to buy their chargers). Elsewhere on the net I found plenty of discussion about which brand of AA’s are best, but nothing that answers my question about how fast they can/should be charged. Finally, this RC Tech forum thread gave me the info I needed. One forum post suggested 0.5 - 1.5 amps.
I’ve always chaged on the low end of the amp range (I charge my racing packs at 4.5 amps), so I went with 0.5. The trade off you get with different charging currents is “punch” vs runtime and battery life. Charge at a high amperage and you’ll get a little more punch, but at the expense of a little bit of runtime and potentially a lot of battery life. Lower amperage carges give you a less punchy pack, but slightly longer runtime, and considerably better overall battery life. As a guy who can’t spend much money on my racing gear, I definately wanna look after my batteries, they’re to expensice to replace often!
I’ve soldered up a 4 cell AA holder to a deans plug so I can charge 4 of my AA’s at a time, and set up a program on the Integy to charge at 0.5A and discuarge at 1A. When I connected it all up and set the batteries to charge the charger immediately started beeping and reporting “Open Curcuit Error” on the screen. I tested all of the solder joints and cabling with the multimeter and they were fine. However, when I tested the batteries themselves, they reported voltages suggesting they were almost fully charged. When I slapped them in the TX, the voltage dropped rapidly, and once the TX reported low battery I took them out again and put the first 4 on charge, and this time they started charging normally.
Heh, now that I’ve figured out how to work around an “Open Cuircuit Error”, I might have to revive my plans to charge my nitro glow warmer off of the Integy. When I last tried that I got the same error and couldn’t work out why it was happening! One charger to charge them all! I’ll also be interested to see how the rechargables go in the Digital Camera too.
A friend recently asked (by email) for advice on Electric Touring cars. I ended up writing a bit of an essay on the subject, so I thoght it might be useful for other people as well.
He’s had Nitro cars before, but is thinking about going elextric and racing at the new Hobby Habit centre on Daws Road. Here’s what I said…
The new Hobby Habit facility on Daws Road is awesome! I’ve raced there twice now, and its just sensational. The new on road track is brilliant, they can change the layout around heaps, and there’s loads of grip (you should hear the tyre howl the modified cars make, unbelievable). The off-road track isn’t finished yet, and may be a bit small for 1/8th scale cars, but overall the facility is top notch.
Normally I’d advise that people get something like a Ho Bao Hyper 10, or a Tamiya TA-04 as their first touring car. Reason being that they’re built a lot tougher than the pure competition cars, so they’ll be cheaper to run while you learn your race craft. Of the two, the Hyper 10 is probably better value for money (better spec, cheaper too!), but I had a Tamiya and loved it. The Tamiya is built like the proverbial brick crap house, and was a good first car. Neither car will be “A grade” competitive, but they’re great “starter” cars.
Continue reading ‘RC Electric Touring Cars’
Armed with a fully assembled Hyper 7, and the usual extras like glow warmer, glow plugs, and fuel, I was ready to start running in the motor.
There wasn’t much in the way of instructions on this with the Hyper 7 itself, but again juls offered some excellent advice. First of all, on preparing to start the Hyper 7’s engine…
Continue reading ‘Hyper 7 Journal - Part 2 (Run-In)’
Of course, every new car should be photographed. Photos of my Hyper 7 are here!
I’ve been thinking about getting a nitro car (off-road) for a while now, it looked like a bit of fun. The cars are bigger and can handle a lot ore in terms of jumps and rough terrain and so forth. I really liked the look and go-anywhere attitude of the nitro trucks, but they proved a bit expensive for my budget.
An added incentive is that the Morphett Vale track is onloy about 2 minutes from home. It’s just been rebuilt and Southern Districts is starting to run nitro off-road racing there. I’ll probably still keep racing electrics competitively, but I wanted to get a nitro car for a bit of fun and social racing close to home.
Continue reading ‘Hyper 7 Journal - Part 1 (Assembly)’
THis is a pretty interesting hack… A bluetooth enabled Radio Controlled Car… Pretty cool!
Found on Slashdot, this guy has onnected an RC Car to his PC and can drive it using one of those Dance Pad things. Pretty cool hack though…
This page explains how to cheaply connect a Dance Dance Revolution pad to an RC car via your PC, for literally minutes of racing enjoyment. Even more fun than the “race tracks” we played with in elementary school, where all you actually did was hold down a button and wait for your car to fall off the track.
The general approach taken here is to use the parallel port to flip the switches in the RC controller, thereby avoiding all the radio stuff. A few transistors are required to help the 3.3V parallel port pull down some pins on the 9V RC car controller.
Source code is included below… it actually just uses DirectInput to talk to the pad, so if you’re burning to drive an RC car around with your PC joystick or keyboard, that works too. If you’re using this approach, the software also tries to pulse the pins on the parallel port to give you some crude analog speed control.
Of course what I’d really like to do is connect up a normal RC receiver to my PC, but thats another story.
I’ve picked up a new race car on eBay… Should be here in a day or two, can’t wait.
You are bidding on a true performance racing car produced by Yokomo. The chassis is equiped with all the goodies found only in top end, high performance racers. The chassis includes: * Genuine yokomo alum. motor mount * Genuine yokomo alum. pulleys * Genuine yokomo front one way * Genuine yokomo reinforced pulley shaft * Graphite gearboxes * Titanium screws all around * Graphite suspension arms * Alum antenna mount Car is hardly used, only ran once or twice then put away. In very top condition. Just add your favourite speedy and fast motor and this thing will launch. This car is built to race!!! I will include two battery packs for the winning bidder…so goodluck bidding.
Found via Sanj’s Yokomo site, the Virtual Race System a program used for lap timing of slot cars, etc. When I eventually get a slot car set (I’ve wanted one since I was a kid), I was planning to have a play with something like this for lap timing. Looks like it’ll save me the effort of writing the software myself!
