Reports flight data up to 100,000 feet!

PerfectFlite APRA Altimeter

  • Part Number (PN): 09107
  • Manufactured by: PerfectFlite
  • Product Specs:
  • Size: 2.75"L x 0.55"W x 0.62"H
             (69.9mm X 14mm X 15.7mm)
    Altitude Report: Always beeps out last flight.
    Accuracy: ± 0.05% typical
    Launch Detect: 100' AGL
    Operating Temperature: -40° to 85°C
                                             (-40º to 185ºF)
    Weight (w/ Battery): 0.56 oz (15.9g)
    Altitude Limit: 100,000 feet (30,480m) MSL
    Battery: Built-in 3.7V LiPo battery
    Operating Voltage: 12V (A23) nominal (4V - 16V)
    Operating Current: 1.5 ma typical
    Warranty: 3 years against manufacturing defects from PerfectFlite.

Product is in Stock (10+)

This altmeter has a high-sample rate from its barometer and simultaneous analysis, eliminating the need for a Mach Delay setting. No data is able to be downloaded to your computer.

Main Features

Beeping Numerical Reporting

The altimeter beeps out the report of both altitude and velocity directly from the device.  No special equipment needed - just listen and receive your stats while it's still attached to the rocket!

Works Up To 100,000 feet!

This unit is meant for nearly all your high power rocket projects, including those really high altitude flights that might otherwise drift miles and miles if you used single-parachute recovery.

MachLock feature for Supersonic Flights

Velocity data is analyzed on the go so as to eliminate errors due to "Mach dip," or the apparent drop in altitude due to increased pressure when the rocket reaches super-sonic speeds. On altimeters without velocity analysis, Mach dip can be incorrectly interpreted as apogee. This in-flight analysis eliminates the need for older Mach delay setting technology.

With MachLock, you don't have to worry about remembering to set the Mach delay on the field - apogee will be determined correctly regardless of rocket speed and your memory.

Hook-up For External On/Off switch

The device also has a separate hook-up where you can (recommended) attach a on/off switch (not included with the device). This gives you some extra protection while hooking everything up for flight. Remember, you're getting ready to set up extra black powder to kick out the parachutes, and for safety reasons, you don't want to set off one of those charges prematurely. That's why you don't want to power it up until it is on the pad and ready to launch.

Built-in battery voltmeter

When you first turn it on, the altimeter reports the current battery voltage. No more guessing about whether the battery is good or bad and whether it needs to be replaced soon. You'll save money, because you won't be replacing a perfectly good battery.

Mounting holes for increased mounting flexibility

Want to fly multiple altimeters at the same time? Then it makes sense to attach them to a mounting plate inside the rocket. They'll then have all the same experiences and you can make an apples-to-apples comparison or get redundant back-up data. Even though the altimeter can be mounted firmly in the rocket, it is small enough and lightweight enough that it can also be slip it into a padded tube for quick installation into the rocket.

Launch Detect Altitude set to 100 feet

Launch detect tells the altimeter when the rocket has started moving upward and that it should start saving the altitude-vs-time data to the memory chip on the unit. This higher Launch Detect value offers more resistance to false triggering due to wind gusts while the rocket is sitting on the pad. The Launch Detect is adjustable from 40' to 300' AGL.

Power loss detection

The altimeter will sound a distinctive hi/low alarm tone sequence on power up if power was lost during the last flight. This doesn't happen very often, but it could tell you that there was some anomaly during the last flight.

How Does This Payload Work?

The PerfectFlite APRA payload works by sensing and remembering the the altitude and interpreting the velocity of the rocket.  It remembers the altitude as such that at the end of the flight, it will know both your peak altitude and speed.


How does it detect a launch?

While the unit is in stand-by mode, it is constantly monitoring the outside air pressure. As soon as the air pressure starts to drop, it figures something is happening. It starts recording information, but will discard it until it senses a pressure difference that equals 160 feet in altitude gain. If the pressure drops this amount, it considers a "true launch," so it stores all the information it has recorded.


How Do Altimeters Work?

The barometric altimeter measures the air pressure surrounding the rocket. Air pressure near the ground is greater than air pressure high in the air (remember, air pressure decreases with altitude, until you reach the vacuum of space, where there is no air pressure). What the unit does is to compare the pressure it senses during flight, to the air pressure on the ground. Using a simple formula, it automatically computes the altitude difference that caused the change in pressure.

How Altmeters Work

How Altimeters Work - A Tutorial

How accurate are altimeters? Which is the best one? These are common questions that are hard to answer, because of the randomness of the atmosphere. This video explains what that means and how it relates to the accuracy of electronic altimeters.

Frequently Asked Questions about the PerfectFlite APRA Payload:

Q. Does it matter what elevation the launch field is?

A. The altimeter samples the air on the ground, so it knows the altitude of the ground level. So when you set it to deploy the main chute at 500 feet, it will know that is above ground level. It doesn't matter where you start.
Reviews for the PerfectFlite APRA Altimeter

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