Altimeters and accessories – Altimax stands for safe function

With the Altimax series I offer a range of altimeters for model and high-power rockets. Through years of further development, I can supply very reliable components which, thanks to their robustness, greatly increase safety when recovering rockets. They can already be used in small models, but even very large rockets can be safely salvaged with them. In addition to hobby model rocket pilots, my customers include national and international universities, other research institutes, schools and the Bundeswehr.

What do you need an altimeter for?

Altimeters are mainly used to recover rockets safely, they ensure that parachutes are ejected at certain points to allow the rocket to land safely. A further field of application is air launches or multi-stage flights, in which additional rocket engines are ignited in the air. And of course the data logging, the recording of flight data such as altitude, speed, etc.

Function:

The Altimax Altimeters are installed in the rocket and measure the position of the rocket there with the help of pressure acceleration and possibly rotation rate sensors. In addition to altitude, the speed and inclination are also calculated, 200x per second. These data are fed into a Kalman filter, which uses all values together to calculate the position of the rocket. The controller of the Altimax constantly evaluates this position and reacts to changes. Since the Kalman filter predicts the position on the basis of the last data, it can react very precisely to changes, e.g. the peak of the rocket is hit very precisely.

Depending on the condition and setting, the altimeter can then activate existing outputs, e.g. ignite an igniter at the summit, which in turn ignites the ejection charge for a parachute. Servos can also be activated. It is also possible to ignite a second stage, e.g. after a main engine has been burned. Altogether 15 events can be connected to 11 “outputs” of the Altimax G3. This makes almost everything possible that can be imagined with an Altimeter. Timers can be started, outputs can be activated or servos can be driven..

All functions are adjustable by PC, with our free Windows software, or also by LCD-Terminal, the terminal is a small device which is simply plugged in and without PC all adjustments makes possible. It can also display flight altitudes. 2-step recoveries are very easy to realize, a small parachute is ejected at the summit, and then after descending to a certain altitude the main parachute is ejected, so the rocket drifts a lot few.

The software in the altimeter also monitors the flight attitude and ignites the parachutes when a crash threatens, so e.g. horizontal flights are stopped reliably and quickly. The larger models also record the measured values, the data can then be read out and evaluated on the PC. In addition to the sensor data, all voltages of the battery and the detonators are also recorded.

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Comparison of the currently offered altimeters

  AltiMAX G3 2016 Altimax Simply 2018
Dimensions 63×25 mm 35×21 mm
Weight 13 g 4,6 g
Input voltage: 7,2 – 12 V 3,3-12 V
Power consumption* (without servos and terminal) Ca. 23 mA ca. 5 mA
Pressure range 10 – 1200 hpa 0 – 1200 hpa
Height range -170 – 31000 m   ASL -170 – 31000 m   ASL
Memory 4 Mbyte
Number of ignition channels 3 2
Number of servo channels 2
Number of additional IOs 3  
Ignition duration 2 seconds 1 second
Ignition voltage =battery voltage =battery voltage
Max. Ignition current 14A (With external ignition battery) 9A
Acceleration sensor Yes +-105G No
Servo supply 5V, max 1 A
     
Resolution Height ca. +- 0,15 m ca. +- 0,15 m (1m output)
Resolution Acceleration +- 0,04G
Samplingrate Pressure 204.800 sps 204.800 sps
Samplingrate acceleration 200 sps
Storage rate** 200 sps / 40 sps
Storage time approx. 6 flights a 10 min.
     
     

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