HyperTEK Motor Info
| Drawings of all the HyperTEK fuel grain and tank combinations, in PDF format. | ||||||||||||||||||||||
| HyperTEK Motor Matrix A list of all the Tripoli-certified HyperTEK motors in Excel spreadsheet format. This will tell you what tank, orifice and fuel grain you need to make a specific motor. Here's the same chart in html format.
|
||||||||||||||||||||||
| Details of each
HyperTEK motor combination (Excel spreadsheet).
html format This chart includes the following information for each motor:
|
||||||||||||||||||||||
| M1000 Thrust Curve (.doc
format)
|
||||||||||||||||||||||
| M1010 Thrust Curve (.doc
format)
|
||||||||||||||||||||||
| This Excel
spreadsheet shows the weight of each motor, to make it easy to figure
how heavy a rocket the motor will lift. I calculated the maximum recommended
liftoff weight by dividing the initial thrust by 5. Here's the chart as
an html file, if you don't want
to mess with Excel.
|
||||||||||||||||||||||
| This Excel file has charts that
plot NOX density and vapor pressure as a function of temperature. Thanks,
Mike Dennett of Cesaroni Technology, for this file!
|
||||||||||||||||||||||
| PDF Drawing of the motor mount/adapter supplied with the HyperTEK M motor system, so you can plan your installation. This adapter takes care of both tank venting and motor retention. This view shows the adapter ring from the back, for drilling purposes. Here's the L adapter. |
HyperTEK Drop Stem Adjustment and Use
(Thanks! to Wayne Mrazek. Visit his superb NowHybrids.com site!)
Drop Stem CTI has developed and put in production a new drop stem system. With the new, more powerful hybrid motors recently released, airframe weights have increased, and so the difficulty of getting them off the stem quickly has become apparent. Some homebrewed systems, like my own, drop the entire fill system out of the motor to release nitrous, or used a spring to help lift the airframe. CTI solved the issues by developing a system that only drops the fill tube itself. The fill tube mount is stationary, bolted to the rail/rod.
In general, this system works great, especially with big, heavy M rockets. However, it is extremely important that the stem be properly aligned with the motor. When many people are flying different size airframes off the same pad, the stem has to be adjusted in or out for each airframe diameter. It this is not done accurately, the stem can bind in the motor, causing the rocket to stay on the pad too long, while the oxygen works as a cutting torch on the inside of the motor. After a couple screwups, (one wasn't enough for me), I no longer install the tie wrap while the rocket is horizontal. I wait until it is vertical, and I can actually test the ease of the stem dropping from the motor. Even a dry Kline valve O-ring can make the stem "sticky". I am using lube on the stem tip and where it slides through the brass bushing. The easier the stem drops, the better. A sticky stem can cause half the grain to burn away before the N20 starts. If there's not enough grain left when the nitrous starts, you will get burn through.
The stem should be set up to drop about 1 inch before the split collar stops on the bushing. If you are switching from J/K motors to L motors, the collar has to be adjusted. If you adjust it for a 1 inch gap when you THINK it's fully inserted into the motor (but it's not), when you try to fill, N20 will pour out of the motor, and you will look stupid. (ask my friends how I know this) The proper length in inches, measured from the tip of the stem to the upper surface of the split collar should be:
J-13 3/8
K-18 3/4
M-21
If you set to these dimensions, when you load a rocket, if 1 inch of stem is not exposed between the split collar and the bushing, the stem is not seated properly in the Kline valve.
