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We ran some performance tests on our finely tuned Johnny Astro using our own power supply as a power source. In all tests, the space vehicle was equipped with a landing carriage and astronaut however no capsule was used. The results might surprise you! |
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Maximum Altitude - 44 inches A maximum altitude of 44 inches was achieved with the space vehicle directly over the fan. The measurement was taken at full throttle, measuring from the ground to the middle of the balloon. In a test using a different Johnny Astro launching station, the space vehicle reached an altitude of only 36 inches. The superior performance of our first launching station could be due to a recent tune-up. The other launching station may improve over time with added use. Lack of use tends to oxidize much of the electrical parts of old toys, especially DC motors. This can depreciate the performance or even keep it from working entirely. |
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Maximum Distance - 55 inches With full throttle applied, the space vehicle reached a maximum distance of 55 inches. It did however retract to about 51 inches only seconds after maximum distance was achieved. With a steady hand, you could lower the altitude to try to gain a bit more distance. It is interesting to note that the maximum distance was achieved with the "autopilot" in place. The distance we achieved exceeded the specifications that Topper claims. In their instructions, a range of 3 to 4 feet is given. The apparent improvement could be attributable to our power supply which closely emulates a new set of alkaline batteries which perform better than carbon batteries. At the time that Johnny Astro was available, only carbon batteries could be bought. Our second launching station did not perform as well, reaching a maximum distance of just 44 inches. The reason is likely the same as we explained in the Altitude test. |
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Minimum Angle - 24 degrees We measured the minimum angle that you can fly the space vehicle without loosing control. In the test, the measurement was taken from the middle of the fan's front face to the middle of the balloon as shown in the "distance" picture above. We found that the minimum angle is achieved with very little throttle applied. |
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Current Draw At full throttle, the DC electric motor will typically draw 500mA. The range of current draw that we have seen is between 400mA and 850mA at full throttle. We have found that this large variation is mostly due to how well the motor is lubricated and how worn the motor is. Excessive wear and a lack of lubrication causes the motor to work harder, thus increasing its current draw. Voltage Johnny Astro was designed to operate from 4 D cells whose series nominal voltage is 6 Volts. In reality, both carbon and alkaline batteries have a nominal output voltage above 1.5 Volts. Depending on the age and condition of the battery, the output voltage can be 1.6 Volts or more per battery. As a result, four D cell batteries in series can have a measured output voltage of as much as 6.5 Volts. The voltage will be the highest with no load applied. |
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Low batteries Carbon Batteries Motor Needs Lubricating Motor Needs Brush Cleaning Oxidized Rheostat (Throttle Control) Propeller on backwards Oxidized Battery Contacts |
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