Water Rocket Car - R/C Steering Working

[thampson]

We have been continuing to work on the R/C steering control for our water rocket car. We are pretty happy that its working as intended now.

A few un-powered downhill runs show it is behaving itself and the servo we are using is up to the job. Here is a video

[ytubehd][/ytubehd]

We have developed a new nosecone to cover the electronics and steering as well. There is an article on our website with a more detailed description of what we did for those interested.

http://wrocket.hampson.net.au/?p=1001

We are now ready to go to the powered test run, hopefully this weekend if the weather holds.

-todd-

[rockets-in-brighton]

We have been continuing to work on the R/C steering control for our water rocket car. We are pretty happy that its working as intended now.

A few un-powered downhill runs show it is behaving itself and the servo we are using is up to the job. Here is a video

[ytubehd][/ytubehd]

We have developed a new nosecone to cover the electronics and steering as well. There is an article on our website with a more detailed description of what we did for those interested.

http://wrocket.hampson.net.au/?p=1001

We are now ready to go to the powered test run, hopefully this weekend if the weather holds.

-todd-

Lovely work - though I still think it is far sturdier than it needs to be... I think you could chop the weight down a lot and get better performance.

Oh, on the downside: a typo in your blog sent me off on a wild goose chase looking for a variation on table tennis that uses giant plastic balls (that could be cut in half and used as nosecones.) Anyone else looking for the same, there's no such thing as "Pig Pong".

[thampson]

LOL .... Good pickup there Steve

Yeah .. I meant "ping pong" ... maybe I should have said "table tennis" .... I will fix that .. thanks

Yes it is a little over engineered but I can now double or triple the volume of the pressure bottles and it will still be stable ... I have another car on the drawing boards already

-todd-

[RaZias]

I think it will be hard to stabilize at very high speeds.

For example, would you have the reaction time required to correct it when it goes at 150 km/h ?

Will the servo wheels have enough strenght to fight against the extreme force of the rocket at that speed ?

That will be the next challenge !!!

I still look to the WRC of the anti-gravity research and it seems that goes very straight, but anyway it´s more a rocket launched in the ground rather a car.

[RaZias]

There were F1 cars with a fan below them, it created a void that would suck the car to the ground.

I don´t know why they stoped to use it, I think it wasn´t allowed by the rules.

You could put a similiar system, with fans from computers for example.

[RaZias]

Here is the link to the formula 1 car with a suction fan

http://en.wikipedia.org/wiki/Brabham_BT46

[thampson]

Thanks for your comments Razias,

I have seen that car you are referring too, it was one of the first the ground effects cars in F1 and you are right it was banned it worked too well .... you can do the same thing now by designing the floor of the car in such as way that it speeds up air under the car causing a low pressure area under the car, you dont need a fan to do it. This works better the faster it goes.

With regards to reaction times, I dont see this as an issue, the videos i have shown so far test full lock but its quite sensitive and it reacts well to small incremental turns. I have the radio range to stand behind the launcher and steer it all the way along the course. Because we use more water than regular vertical roeckets we dont have the explosive first 1/3rd of a second like the vertical rockets, our acceleration is smoother and comes on over a longer period of time so there is more time for steering input.

The servo I believe will be strong enough, this servo is designed for large scale r/c planes and cars. The servo's used on the planes control air surfaces directly in the 150+km/hr air stream and work very well.

Im sure we will see more engineering challanges as we push the envelope of distance and speed with this car (and the next one) but that is the fun of this hobby

-todd-

[Jelo]

thats pretty sweet im just thinking, you should put some kind of piston like the ones that are on some motorbike handles, they absorb the big vibrations and when an imperfection such as a pebble or stick is on the road, it would stop the wheel from turning accidentaly. maybe when your steering system is fully developed you could try to do that, i think the fact the wheels can move will make them move without you wanting them to do so, i tried putting a WRC on a radio controled car and the wheels would just move by themself due to the servo not been stiff enough... thats my oppinion, maybe it wont happen at all for you if your using a plane servo, there usualy designed so the flaps dont move by themselves