oh,,,i thought that was a smoke machine from a stunt plane!!!!

 

it for when there no fire we can still roast the dogs[img]i/expressions/face-icon-small-smile.gif[/img]

 

Houndog06 and MichaelAZ, I understand the skepticism....really, I do. In fact, I don't blame you. After all, a rocket on an ATV is unusual. But, if you understand the concept of a JATO rocket engine, it is simply that, a JET ASSIST device. It essentially unloads the combustion motor and allows it to work harder/faster. Think power to weight (physics and the laws of motion). If the rocket provides 300 pounds thrust, the combustion engine needs only to overcome another 300 pounds (rider and bike) and inertia. Once intertia is overcome, the bike continues to accelerate. And as for actual thrust, yes, we have throttled it up to where it can propel itself, but it is extremely unstable. Oh, and by the way, we throttle it by regulating the NOS/O2 pressures, which are nothing more than oxidizers. No, it takes very little PVC, and at 2500F, there is very little bi-product because chloride is completely consumed at 1300F, that is why it is an effective fuel grain. These type rockets are not my personal creation, they have been around for several years are typically referred to as "hybrid" motors. They are ATF legal and have no HAZMAT applications. In fact, my motor was conceptually designed by Ky Michaelson himself. He is the "Rocket Man" that was profiled on Discovery Channel recently during rocket week. This particular rocket design has propelled his mountain bikes and sleds under their own power. Mine is a larger version essentially on steroids. If that doesn't convince you, Dunefest 2004 is a public event. It'll be debuted there and I intend to run it at 400lbs thrust. During 100 yard drag tests, it has reduced the elapsed times nearly two seconds. Unfortuneately, it can only be engaged at second gear roll-on, and a good portion of a race is over by then, so sometimes it becomes a game of catch-up. Hope this helps explain the project. And yes, the rumors are true, I am also working to apply a gas turbine engine and hydropneumatic drive system to my Raptor when I retire the rocket this summer after Dunefest.

 

Love the fire!

hate to be a skeptic

but, 300 lbs of thrust would rip the handle bars from your hands.

300 lbs of thrust is MORE than enough to propel your quad, in neutral, up a 60 degree hill.

Are you sure about that 300 lbs of thrust?

 

Bottom line is your engine essentially thinks it is pulling 300lbs instead of 600lbs. I do not see that equating too 2 seconds in 300'. I could see 1 second difference though. It's good too be thinking outside the box though.
Gary

 

If you put wings on a 400 lb quad with a 200 lb rider, and gave it 300 lbs of thrust, You could take off and accelerate in the air while traveling upward at a ~35 degree angle!
[img]i/expressions/face-icon-small-happy.gif[/img]


I can't understand why 300 lbs of thrust won't move your quad. [img]i/expressions/face-icon-small-confused.gif[/img]

 

What, no Flux Capacitor??? My Delorean would smoke your Raptor. -Marty McFly

 

TRX440, that was too funny......loved it! To answer the questions. Yes, 300lbs will move the quad from a static stop. In fact, I have a hilarious test video where I ignited the the first generation motor and the quad ran away for about 20 feet before I pulled the safety tether. During this test, we measured the pull using a simple 500 pound protracted lateral scale on the tether. The reason only 300 pounds setting was chosen is that anything more is inherently unstable and downright scary, especially on a quad. Also, the 300 pounds, when ignited is almost immediate, meaning it would impose huge stresses on it's mounting (swingarm and shock mount), that's the reason for waiting till inertia is overcome by having the Raptor already moving. As for the one versus two seconds, it has been tested and measured as accurate, depending on reflexes, track conditions, etc. I can't be very consistent since I'm not very good at sand drags, especially at my ripe old age. I'm sure a younger and faster rider could get better results.

By the way, I apologize for being so long winded on these chats. My background is in engineering and I'm a fed, so that's two strikes against me. I have to constantly remind myself to simply GET TO THE POINT. Have fun!

 

Afterburner,

I have a fairly good understanding of JATO (Jet Assisted Take-Off) rockets (more correctly called RATO [Rocket Assisted Take-Off] Rockets. I agree with some of the things you have said, yet much still rings false. First of all, according to the first law of motion, in order for an object to move, a force must be applied to it greater than that equal to the object's static friction. A person can easily roll a bike by pushing it. However, you claim that your engine exerts 300 lbs of thrust but will not move the bike on its own. There is no way a person is exerting 300 lbs of force on the same bike, yet it moves easily. Ergo, your engine cannot be exerting as much force as the person.

Further, you claim that you can throttle your rocket by increasing the amount of oxidizer. However, solid rocket grains are designed to have the correct amount of oxidizer premixed into the grain. Adding extra oxidizer would simply create excess and provide no contribution to the combustion.

I have a couple of other questions. What metal did you use for your combustion chamber and is it single or double walled. Is the chamber insulated? If so, with what material.

Also, you mentioned that the rocket can only be engaged in second gear. Why would the position of the transmission have any effect on a completely external engine?


~HoundDog

 

HoundDog,

I appreciate the fact that you are obviously knowledgable and I respect that-REALLY. But, is there a sound reason for the bashing (i.e. "rings false")???? Has my rocket design insulted you in some way? If so, you have my sincerest apologies, wasn't my intent. I only published this project development for the simple sake of sharing in the fun. But, to further answer your questions:

First, second gear to overcome inertia and inherent structural stresses at ignition.

Second, it's a HYBRID, meaning the oxidizer is injected and throttled, not mixed, in the grain as in typical solid fuel applications.

Third, a jet is appropriate terminology for JATO. In aviation applications, there is no common term as RATO, neither in military or commercial application. (Trust me, I AM a noted authority on this topic and we run JATO capabilities on our DC-9-30 and Metroliner series aircraft) The reason for the common “jet” term is that a jet is, by definition, an engine that produces motion as a result of the rearward discharge of a jetted reactionary mass in motion. For instance, an airplane or rocket engine uses atmospheric or stored oxydizer to burn fuel and produces a rearward discharge of heated air or exhaust gases, i.e. JET.

The idea behind my simple solid-fuel hybrid rocket is straightforward. What you want to do is create something that burns very quickly but does not explode. As you are probably aware, gunpowder explodes. Gunpowder is made up 75% nitrate, 15% carbon and 10% sulfur. In a rocket engine, you don't want an explosion -- you would like the power released more evenly over a period of time. Therefore you might change the mix to 72% nitrate, 24% carbon and 4% sulfur. In my case, instead of gunpowder, you get a simple rocket fuel such as PVC (poly vinyl chloride) and add the oxidizer until the appropriate burn is achieved. This sort of mix will burn very rapidly, but it does not explode. My rocket is cylindrical, with a tube drilled down the middle of the PVC. When you light the fuel, it burns along the inner wall of the tube. As it burns, it burns outward toward the casing until all the fuel has burned. The "combustion" chamber is the PVC.

I understand your concerns that my system has certain aspects that "ring false". I hope I alleviated your curiousity and negativity. You don't have to believe it and I don't fault you for it. After all, it is unique and different. Everyone has an opinion, and I respect yours. BUT, I am the one with the working JATO. As the video credits show, it was jointly developed by NAPA, ALBA, Marion Performance Specialties and in design collaberation with a nationally recognized rocketeer. If you really need proof that it works, come to Oregon Dunefest, have some BBQ with us, and line up at the starting tree. (Wear earplugs-it's REALLY loud)