Mock Nitrous in my Xmod!

[xxspeednplayaxx]

well this is dangerous, insane and will mostly end with a broken xmod I LOVE IT.. just throwing out ideas but rather than addidng more wieght to your xmod (pcb, alothough not alot its stil added) you could wire the rockets to the motors brake function (not sure how) or seeing how this a soely drag racer, you could wire rockets to the seating control.. just make sure you lock the wheels up good.

and like many i wanna see a video of this, lol the look of your drag opponent's face should be priceless!

[xmodsman]

I AM INTO ROCKETS AND U NEED TO CONNECT WIRES TOTHE IGNITER ITS NOT REMOTE CONTROL.but on the other hand u could make it remote control if ur that smart.or buy a pack of ten remote control premade igniters that will drop you wallet around
50$$$$

but that would be sooooooo cool

o yeah dont blame me if im wrong im only 12 but im not stupid

[Exaran]

Can you guys explain to me again why you would want the exauasts on either side, instead of in the middle?

I've had quite a bit of physics , and an adolescence and a half of blowing stuff up, and I would say to mount the exaust in the middle of the rear of the car. A slight misalignment of the motors will not cause any forces that you will be able to notice (They are pretty wieny motors on a pretty heavy car) I would also not fear the engines causing the car to fly. Your primary concern should be one engine lighting and one not. If this happens with your exausts far apart, the car will be much more likely to lose control. If only one fires and your outlets are close together, you will only notice a small pull, if anything.

I would also SERIOUSLY reccomend against using a X pipe or a H pipe to connect the two engines. This will only cause turbulence and heat, and ruin the performance of the engines. (sure it would equlize pressure, but it would slow exit velocity, and thats what a rocket is all about)

....hmmm, about that. It just dawned on me that if you are running the "exaust" thru a pipe system with bends in it that is larger than the smallest part of the nozzle on the engine, (I'm assuming your pipes were going to be as big as the enigne) then the gasses may just expand and slow in the first bend, and all you'll get from the exaust is some smoke and no power.

....man I keep thinking of more stuff... Have you noticed if you use a model rocket launching platform with a metal blast pad how the motors leave a scorch mark through the metal plate (can see it on both sides)? Make sure your piping can handle that kind of abuse

Good Luck! This can work

[sawhit4]

yeah i dont really get why you would want them on the side. if you put the on both sides then you will have to ignight both rockets at the same time so it doesnt push you to one side of the street or whatever you run it on. if they are in the middle you still need to hit them both at the same time but it wont make that much of a difference if you half a second off. or even better you would mount one of top of the other and then hit one and then hit the other. and i dont even see what the tubes are for why not just most the rockets on the back of the car. the tubes are just gonna slow you down and then might not work right (im gonna test this with my torch in a few minutes so i might be wrong.) anyway im only 13 and have never had a physics class but that doesnt mean im ignorant about things like this. as for remote ignighters heres how.........the ignighter is a switch right? that sends an electrical charge the the rocket motor. so you hook up a servo to a switch and hook the switch to the motors and a battery. you can check this out at http://www.geocities.com/cheeta_rc/index.html thats what i think you should do with the motors at the back of the car but not under it like he did

[MidWestRacer]

The reason for side exhausts is to keep the car straight (think of Pontiac's old slogan .... "Wider is better"). You would have to make sure that the bends are not too big, I hadn't thought of that part before. As for Xmods"man" (at 12 you say????) you can remotely ignite the rockets w/o buying expensive pre-mades. You simply hook up the igniter to an RX (receiver) board which is activated by the TX (transmitter) board through RF (radio frequency ... what the XMods and most other R/C's use). To Sawhit, I have no idea why you would have a servo hooked up to the system, a servo is a motor. All that needs to be done is hook up the igniter to some type of PCB/Board that would control when it fires. I'm thinking some type of Hi/Lo system by hooking it up to the headlight circuit maybe??

Basically, you would hook up the positive from the Headlights to the base of a NPN (Negative, Positive, Negative) transistor. For the NPN transistor, the wiring would (I think) be as follows:

Base (middle lead of NPN) would be hooked up-to the Positive for the headlights. Collector (first lead of NPN) would be hooked up DIRECTLY to the negative of the battery pack. Emitter (last lead of NPN) would be hooked up to one lead of igniters (make sure to wire igniters in parallel for "sure-fire").

For the other portion of the igniter PCB, you would use a PNP (Positive, Negative, Positive) transistor, the wiring would be just the opposite:

Base (middle lead of PNP) would be hooked up-to the Negative for the headlights. Collector (first lead of PNP) would be hooked up DIRECTLY to the positve end of the battery pack (opposite pack from before, you want as MUCH voltage going to the igniters as possible). Emitter (last lead of PNP) would be hooked up to the other leads of igniters (again making sure to wire igniters in parallel for "sure-fire").

All of this SHOULD ignite both igniters/rockets at the same time the very second that you pull the trigger for the car to move forward OR backward!! If you notice when you drive your XMod, the headlights go bright in both directions, but the taillights only go bright when you hit the brakes. BEFORE you do this, you will want to make sure to have the design checked out by someone that has plenty experience with electronics such as this.

WARNING!!! (have to have this) If you do not have experience with making the following electronics, be EXTREMELY careful or you will likely kill/maim yourself The colors at the bottom are as standard ... red = positive, black = negative; the colors at the type end (the leads of transistors) are labeled in the JPG image.

Have fun

Here is the graphic for it:

[sawhit4]

well i guess you didnt look at the link i put up cuz if you did you wouldnt ask that question. i shouldnt have said i was 13 cuz people think they have to talk down to me and explain things like servos. and the only pcb i can think of that would work that would be inexpesive would be a bit and i dont think it puts out enough voltage. but who knows ill probably be wrong on this one too.


EDIT: i probably wasnt clear enough in that post. if you use a servo or magnet actuator to activate a switch you dont have to worry about the pcb not haveing enough voltage to ignight it

[Exaran]

if you think you can get the engines to light within a split second of each other, you obviously haven't used any estes model rocket engines and electronic igniters.

I would say that they vary from instantaneous to about 5 seconds. No tellin

[viperdout]

This is dangerous, and that's why it's cool! If this isn't exactly right, you're gonna have an intimate chat with a curb or an airplane. You should just go JATO style, and mount this baby, sans body, on top of the car. This is about as risky as me putting 17 volts in an Xmod. Most likely, it'll be a bunch of parts at the end of this, but there's a small chance of sucess. I think the best bet would be to use a CO2 rocket. The worst case scenario is that you freeze something. I got a car about half of the weight of an X to 60 mph, so it should do somewhere around 30. The best thing is that it's compact, and has no chance of exploding, unless you drilled a hole in it. You just have to figure out how to pop the canister. This would also allow for aluminum exausts or even wood ones! I think that is the solution.

[MicroSpeed]

Originally posted by Exaran
if you think you can get the engines to light within a split second of each other, you obviously haven't used any estes model rocket engines and electronic igniters.

I would say that they vary from instantaneous to about 5 seconds. No tellin

I've clustered motors in some of my rockets, and if you have enough voltage/current, they light reliably within 1/4 of a second

[MidWestRacer]

Exaran, I have used an Estes before (note that I did not say many) .... I had a nice lil rocket, flat black, about 2.5 feet long or so, orange streamer recovery system ... me and a buddy put a C class in it on a day that had about 400' ceiling (somewhere around there, anyway ... it was 4 yearz ago!) for a Physics/Chemistry project. Well, we lit it off w/ my lil ghetto rigging (7.2 battery from LHS designed for safety igniter, except that my safety igniter POS didn't work) and, needless to say, it went way above the clouds, and when we finally saw it again (on descent) ..... it was directly above a factory roof

So, I have used a couple Estes before (before the above rocket we used a Class .. B I think in my buddies rocket). MicroSpeed is more than likely right about using enough voltage, though.

[sawhit4]

on the website i put up im not sure what kind of rockets he uses but it uses a 9 volt charge to ignight them. i know for a fact that the bits dont use over like 2 volts so thats probably not gonna work but making an actuator from the steering and using a very sensitive switch you could do it. i have a half working pcb (the steering doesnt work) from an old toys r us that uses a nine volt motor. im thinking about a rocket car but it will have to wait untill i get some time.

[Uber_hampster]

ignore this. look at below

[Uber_hampster]

Estes engines arent the most reliable things in the world. If I were you, i would explore other, more precise engines. Through much experiance with rockets, I can tell you that they will not light all at once except for a freak accident, or u can wire in some voltage regulator that will apply the power all at once. My worst experiances were: a rocket took about 30 seconds to take off. I tsmoked for a while, the fizzeled out. A couple seconds later, the rocket took off. My other one is that once, the rocket just exploded on the pad(not James Bond boom, but tor the cardobard tube apart and set it on fire), and as any rocket enthusiast knows, half the tim, these things dont even light. Lastly, in elementry school, my friend tried making a rocket powered styrofoam skateboard, using a cluster of 4 engines. They did not all light at once, and it didnt do much anyway(except melt styrofoam).

One the subject of Co2 cartriges. They are efficent and reliable, the problem would be puncturing the cases (as already mentioned). I supose you could have some sort of swinging gate with a pin and spring, but that would take time, and might not work properly.

[sawhit4]

the problem with that is the gate with the pin to puncture the co2 cartradge would just pust the car before it punctured the cylinder and if you put something to keep the car from rolling it wouldnt go anywhere when the thing did get punctured.

[Uber_hampster]

I remember my middle school had this big, computer controlled setup that puctured it and relaesed a starting gate(or something like that) at exactly the same time, then monitored the speed, accel, etc.