🏆 Altimeter Cloud

Rocketry Competitions

Win prizes and earn respect. Enter your flights into our challenges — check the rules, fly high, and claim your spot on the leaderboard.

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The £500 B4-4 maximum altitude challengeThe £500 B4-4 maximum altitude challengeThe £500 B4-4 maximum altitude challengeThe £500 B4-4 maximum altitude challenge
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Prize pool
£500.00  $663.14  €578.99
🏆 Top entries
🥇Trevor303.6 m
🥈Eddie203.7 m
🥉Louise161.7 m
⏱ Time remaining
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days
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⏱ 191 days left Active
Entries
4
Top apogee
303.660 m
Closes
20/09/2026
🚀 Enter your flightView leaderboard →
🎯 The Challenge
This competition is open to everyone, even penguins, if they fancy it!

On 4 dates over the next few months we will award gift vouchers to use on modelrockets.co.uk to whoever is winning the challenge and if you stay on top you can win each time and grab it all!

The challenge is to build and fly a rocket on a Klima B4-4 rocket motor with a Mercury V1 altimeter to the highest altitude. It's that simple!
You can fly any kit or make your own rocket. Although, I suspect you will probably need to build your own to win.
📝 The Rules
Your flight must meet the following rules (don't worry it's not too tricky).

Your rocket must fly on a single Klima B4-4 motor with no other method of propulsion.
You must use a Mercury V1 altimeter and upload the flight to the Altimeter Cloud.
You must add your flight by entering the Altimeter Cloud flight ID or URL here on the competition page.
Your rocket must come down slower than it went up (some form of recovery system worked at least a bit).
You can submit as many flights as you like.
Our decision is final, if we think a flight isn't legitimate, we'll play it safe and discount it from the compeititon.

As altimeters can be added to multiple accounts the prizes will be emailed to the most recent account added to a Altimeter to avoid confusion.

Your Mercury must be running firmware 2.10 or later and the Kalman filter must not be disabled or your flight will be rejected automatically. You can update your Mercury with ease on our firmware updater page if you need to.

Please note that your flights on the Altimeter cloud are public, so we suggest not putting any personal information on your flight notes or uploaded image.
If you are aged 16 or under you must have your parent or guardians permission to enter.

🏆 The Prizes
We have split the £500 into a few prizes, and whoever meets the criteria at each date will win a gift card to modelrockets.co.uk, for the amounts as follows.

15th April £75 to the current highest altitude.
31st May £75 to the current highest altitude.
10th August £100 to the current highest altitude.
20th September £50 to the second highest altitude (must be a different person)
20th September £100 to the highest under 16 years old flight.
20th September £100 to the highest altitude.

Don't forget you can keep winning prizes if you're still winning at each date!
No cash alternative is available, prize vouchers will be emailed to the latest user to be added to the altimeter that flew and won.

Best of luck to everyone!