Around 150 bottle rockets will work, but that's not important. What is important is that you don't want to be there when all 150 suddenly expire and go "BANG".

As for times & numbers. The quickest we ran with the rocket was 4.6 seconds, but using a stop watch on a closed local 100yd sand dragstrip. The fastest was 102 mph using the installed trailtech computer and in a wide open dune area. BUT, THAT WAS PANT FILLING SCARY! It got real squirrly above 90mph and progressively worse. I wouldn't do it again without AT LEAST a steering stabilizer and a lowering kit. My ride sits tall, wide and long. The tall part hurts the rocket's performance.

I'm too old for this....................................

 

Afterburner,

First let me apologize. I never meant for anything I have said to insult you or attack you. I don't doubt that there is a good possiblity that your rocket could work. I have simply been trying to gain a better understanding of its physics. I spoke to chris at alba about your bike and I am fully aware of your creditials. Your reputation and your background in engineering preceeds you. I work for the USEPA and have a background in biochemistry and chemical engineering. Again, I beseech you, please don't take offense to anything I have said. I have simply been trying to probe for information for better understanding for myself and the other forum members.

As to my comment on the proper naming of such an engine, I visited the national aeronotics division's historical page for a little info on the evolution of JATO's. They are the ones claiming improper use of the name and renaming it RATO. The US Air Force's JATO history also mentioned the maluse of the term.

Regretfully, I will not be able to make it to the Oregon dunes. I simply cannot afford a trip of that distance. I do appreciate the invitation however.

Could you enlighten me as to the composite shell of your rocket. I am still curious of the alloy you used to construct it and what insulations you might be using. You mentioned getting a burning temp of 2500 degrees. That is the average melting point of carbon steel. Are you using something with molybdenum to bring your melting point higher?

I am sorry about the questions regarding your fuel grain. I simply missed you mentioning it being a hybrid in an earlier post. What is the oxidation mixture threshhold for your fuel?


With humblest curiosity,

~HoundDog

 

No worries, I really do enjoy a good debate. EPA? I'm impressed. I work for the safety and enforcement arm of the FAA. Chris gave me a ribbing over your chat, too. They're a great bunch at ALBA down there. As to the shell, it's aluminum. Most hybrids don't use a shell, just the PVC and they measure the consumption rate to prevent burnthrough. As to the temps, the only critical component is the convergent/divergent nozzle, which is the actual motor. It was machined from graphite (what a mess on the lathe!). Without using expensive exotic metals, it was the only option for the temperatures we were gonna run. Later! By the way, how do you like your 686?

 

afterburner,,,,get your pic/bio page up and running,,,,for the rest of us to see.....

good looking rappy (similar to my own),,,,,watch out for traffic......

 

This IS a great thread! I haven't enjoyed reading a thread this much in a long time. Thanks HOundDog and Afterburner!

 

Afterburner,

I hope Chris didn't get the wrong idea. I at first thought the bike was a joke. After talking to him, I soon realized the contrary. The guys at Alba are world class. Matt in the parts dept. is a good friend of mine. I even run one of their graphics kits.

I figured the shell was probably aluminum. Are you using any inhibitors to help prevent the burnthrough? Do you know what the consumption rate is for the PVC grain you are using?

I would never have thought to use graphite for the nozzle. I was thinking more along the lines of a high temp alloy. How did you attach the graphite securely to the nozzle area? Did you have any problems with damaging the graphite due to its brittle nature?

I love my 686. I shiver when I think how much money I have put into her though. I'm sure you can relate.


Alpha Raptor,

I'm glad we can keep you entertained.


~HoundDog

 

We have a steel mill locally that utilizes graphite for casting. I got a big square chunk donated and I milled it into a nozzle. I won't kid ya, it's beefy and heavy. That was to allow me to tap it out and insert high stress rods that could sandwich the fuel grain case between the nozzle and the intake plate. I use no inhibitor, not necessary as long as I monitor the burn consumption rate by way of a caliper. The burn is extremely predictable and consistant along the ID wall. Not a real safety issue either since the fuel grain chamber pressure is very low under the flow characteristics being experienced within the PVC (Bernoulli's Principle). I concur about ALBA, they are the best in the industry. At my age, I consider myself fortunate that they sponsor me as a racer. Also, it's funny that there has been so much focus on the rocket. Didi you know there's a separate string in this forum addressing (arguing) my supercharger (E-Ram) development?

 

This is great to read, I personally would not want to get into a chemical debate with either houndog OR afterburner. I comend you fellas for debateing in such a respectfull way.
I am curious to see how consistant the E-ram is though. Ive wondered about this type of air ram, But always thought efi would be needed to moniter fuel and air. But what do I know.

Houndog, I still think a more rounded out paddle hooks up better. Remember the argument?(lol) I WILL NOT argue the fact that you know your stuff when it comes to rockets..

[img]i/expressions/face-icon-small-shocked.gif[/img]

 

Annihilator,

I think you may have contributed to the discussions under the Yamaha Forum about my E-Ram development (or I could be wrong-feeble minded and all), but the biggest hurdle was compensating for the positive pressure within the carb intakes in lieu of the typical vacuum. I went two ways to overcome this. One was to route a presure line to the bowl vent system to equalize the bowl pressures to the same psi as the intakes. That works, but you need to have a regulated fuel pump that will overcome the bowl pressures but not unseat the float s/o pin when the bowl fills. My second and best working option was to install dual injectors into the carb intakes. Both have been tapped for main jet installations that are one size larger than my normal mains. So, at wide open throttle, when the supercharger kicks in and forces my normal mains to stop flowing, a fule pump kicks in and sprays fuel into the carbs with the hiflowing air. The E-ram only produces slightly above 1psi, but at 750 cubic feet per minute flow. The dyno results are only 3-4 horses, but it's the torque and acceleration curves that were dramatic. On my Raptor, the peak HP (without NOS activation) is 62 at 4500 rpm and stays consistent till it tapers off at higher rpms. With the E-ram, my torque curve was nearly vertical and maxed at 65 HP BEFORE 2000rpm. On the sand, it nearly pulls your arms out of their sockets. the feeling is similar to the NOS hit at a 30HP jetting setup (I normally run only at 15-20 HP jet setting). ...........................Geez, I'm a blow-hard!!!!!

 

LOL. I remember that discussion Annihilator. Thanks for the kind words. I apologize for my absense on the forums today. One of my colleagues was injured during a sampling expedition at a local Air Force Base and I had to help get some of his technical directives turned in by due date. Made for a pretty busy day for me.


Afterburner,

I haven't had a chance to check out your thread concerning your ram air system yet. I have some ideas for an EFI system that might work well with such a setup however. Look forward to talking with you about it later.

I will be absent from the forums this weekend. I am leaving early in the morning for a weekend trip to Little Sahara, OK. Look forward to talking with you gentlemen next week. Happy Riding!


~HoundDog