HPR Alternative...Hypertek!

Well, I have been pondering the demise of Aerotech's motor plant and am considering trying out Hypertek Hybrids for I - M loads. Any suggestions or comments?

So, who's with me?

Do they make 29mm E,F,G?

I saw a couple of hypertek launches. They were very impressive. Before I venture down that path I need to get some experience with dual deployment.

Originally posted by CTulanko
Well, I have been pondering the demise of Aerotech's motor plant and am considering trying out Hypertek Hybrids for I - M loads. Any suggestions or comments?

So, who's with me?

Click to expand...

I too am seriously considering trying the Hypertek hybrids.

I know that our Tripoli prefecture owns a Hypertek ground support setup. The only reason that I hesitate to invest in the motor hardware is because rarely does anyone in our prefecture fly hybrids and I've never heard anyone praising the Hypertek motors.

Granted, I've not heard much negative feedback about them but, I've not heard much positive feedback either.

Who out there uses these motors and is happy with them?

I have also been giving it serious thought. One nice thing that I have been hearing is that the grains can be used twice.

Originally posted by Tony
I have also been giving it serious thought. One nice thing that I have been hearing is that the grains can be used twice.

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Only some of the grains can be used twice. There is a special reload that allows you to use them twice. And I don't think that any of the EFX reloads can be used more than once.

Wait, wait, wait... WHAT??? Grains used more than once? Maybe I'm getting my terminology mixed up but isn't a "grain" the thing that burns to ashes just after it creates that phenomenon that we love about out hobby: Thrust? How can they be reused?

Isnt that kinda like saying that you can reuse the black powder after ejection?

In a Hybrid motor, the "fuel" is usually, but not always, some type of thermoplastic. This plastic is formed into the combustion chamber.

On a composite motor, you insert the igniter up thru the nozzle and when ignited, it burns the propellant and exits through the nozzle.

On a hybrid motor, the igniter (if one is used, more on that later) is inserted the same way and when ignited, it burns through the nylon hose which also was inserted thru the nozzle (Rattworks and Propulsion Polymers) and is used to fill the NOX tank. When the hose burns thru, the NOX flows into the combustion chamber and promotes the burning of the thermoplastic through oxidation.

The thermoplastic doesn't necessarily all burn up like typical composite fuel. Therefore, the thermoplastic fuel grain may be used a second time. Keep in mind that due to burning, the shape of the combustion chamber is probably different and will yield differing thrust characteristics.

For example, (from the Pratt Hobbies site) an I205 fuel grain with a total impulse of 470Ns can be refired as an I222 with a total impulse of 519Ns.

Earlier I said if an igniter is used... The Hypertek motors don't use a pyrotechnic ignition mechanism or a nylon fill tube. They use an electrical spark combined with gaseous oxygen to begin the burning of the fuel grain. The rocket is also secured to the launcher by a plastic tie down strap, which keeps the seal between the combustion chamber and the NOX tank closed. When the tie down strap burns through, the pressure from the N2O tank lifts the rocket (or the fill mechanism drops for larger rockets) to break the seal from the fill tube to the NOX tank and begins introducing N2O to the combustion process.

Hope this helps

Ahhhh, OK. Thanks... I didn't realize the thermoplast doesnt completely burn... Very interesting.

Well, I took the leap. When I got home from work today, waiting for me was a package from Star Rocketry. I purchased the 440cc Hypertek 54mm Standard "J" motor system. I also purchased the 300cc tank so I could do a couple of "I" flights.

The plan now is to use the Hypertek system to certify Level 2.

Earlier in this thread there was some question about reusing fuel grains. Here is the real scoop. You can reuse the Standard "J" fuel grain when flown with the 2 certified orifices and the 300cc tank. This gives you 2 "I" flights on 1 fuel grain. At $26.00 for a fuel grain that makes it $13.00 per "I" flight. That's cheaper than some "H" reloads! Note: You cannot reuse HyEFX fuel grains!

I'm really excited about getting a chance to fly these things!

Best hav a full report of the first flight!!

Originally posted by Klint
Best hav a full report of the first flight!!

Click to expand...

Absolutely! We'll have some pictures too.

Just a question,
Has anyone looked at the new AeroTech Hybrids? I realize their plant burned but I am assuming that they again produce these in the not to distant future. I have heard that there are some advantages to the A-tech sytem. first that I know of is that you can use their 54mm and 98mm casings and also I have heard that you can have the flight cylinders prefilled with N20 at most speed shops.

Any comments?

I looked at the Aerotech Hybrids before settling on the HyperTek system. The AT system has advantages and disadvantages. It's nice to be able to use the 54mm casing and to be able to pre-fill the oxidizer tank. This negates the need to have special launch equipment to fire the motor. However, the AT hybrids are much more expensive on a per shot basis than most other hybrids. Also, getting the tanks refilled at a speed shop is an expensive and not very flexible solution. Chances are good that you'd probably want to launch the motor more than once at your launch field. Therefore, you'd need to have the refilling equipment and a tank of N2O with you. Now, the cost compared to a Ratt Works or Propulsion Polymers motor is not so attractive. My decision was mainly influenced by the fact that our prefecture owns the HyperTek launch equipment and HyperTek is the de facto leader in hybrid motors right now.

Thanks Mark!

David,

I have attached an article "The Great Hybrid Flyoff", a bit dated, written by Bruce Kilby that compares AeroTech Hybrids to HyperTEK. It gives the pros and cons to both systems. Again this is a dated article. HyperTEK, which I am familiar with, has since introduced HyEFX grains that have more power with still no AP and an expanded line of motors that are standard diameters 54mm, 75mm and 98mm. Also HyperTEK does not require a LEUP on any of its motor configurations.

Hope this helps answer some of your questions.

Oscar

The attachment on my previous msg does not seem to open - at least for me. I will try posting it again with a smaller title. If it still does not work then just pop me an email and I will send it to you off line.

Oscar

I think you need to have the extension as .DOC instead of .TXT. Here is the corrected file. Thanks for the info. It is great. Like Mark, I do plan on starting hybrids soon.

Hi guys,
I can't seem to get that file to open. It wants to save as "attachment.php." Any chance you could email it to me?

Thanks
David

David,
Are you talking about the zip file attachment? Each time I click on it, it asks if I want to open it or save it to disk. Do you have Winzip installed on your PC?

I think the problem is between the keyboard and chair

the first one opened fine for me...

Hi Guys,
No EBKAC here. The problem I am having is with the filename extension php. My system doesn't recognize it.

Suggestions?

There is no filename extension .php. The extension is .zip. I'll try emailing the original file to you with a .doc extension.

It tried opening as a *.php for me as well. I suspect this is because this website runs PHP, and the link is a plain text document, which often gets changed by whatever application tries to open it [especially Outlook].

A *.doc would definitely help. If it were me posting the link, I would have posted it as an *.html just out of personal preference.

Is everyone who's getting the .php extension using a MAC?

It's the software. The link links to a php file, which in turn will open the attch and send it to your computer - it's so that other people cannot link to it directly. Click on the link (or open in new window), and it will ask you to open or save a zip file, do not use "save link as...".

Oliver