Fly a D motor above 300 meters
A D motor and a light, well built rocket will comfortably clear 300 metres. This one's just for the fun of it: fly past 300 m on a D motor and you're in the club. It isn't a race. Everyone whose flight reaches 300 m wins the points, once each. Fly as often as you like: your later flights go on the leaderboard, but the points are paid once per flyer.
About this challenge
A D motor and a light, well built rocket will comfortably clear 300 metres. This one's just for the fun of it: fly past 300 m on a D motor and you're in the club.
It isn't a race. Everyone whose flight reaches 300 m wins the points, once each. Fly as often as you like: your later flights go on the leaderboard, but the points are paid once per flyer.
Which motors count as a D?
Any motor with 10.01 to 20 Ns of total rated impulse, such as the 24 mm Estes D12-5 and the Klima D9. The class goes by the total for the whole flight, so two D motors in a cluster make an E and won't count.
How to get to 300 m on a D
- Keep it light and slim. A 24 mm rocket built around the motor goes far higher than a big sport kit.
- A smooth finish, an ogive nose cone and thin, sanded fins all help.
- Pick a delay that fires near apogee, and use a streamer or a small parachute. From 300 m even a light rocket drifts a long way.
- Fly on a calm day, straight up, in a big field.
- Weigh the rocket ready to fly and enter the lift-off weight on the flight page.
Entering your flight
Upload the flight as normal, then on its flight page add the motor and the lift-off weight, and set the launch site, date and time. Then open the Add my flight tab here and pick it.
Fly safely, and follow the safety code of your club or national association.
Your altimeter works out height from air pressure using a standard atmosphere: the sea-level pressure and temperature in its settings, usually 1013.25 hPa and 15 °C. The real day is rarely standard. Cold air is denser, so an altimeter set for 15 °C reads high on a cold day and low on a warm one, by roughly 1% for every 3 °C, which is about 2 m at 200 m.
So every flight is judged on the height it really reached, we take the weather added to your flight for its launch site, date and time, and recalculate the whole log with it. It's the same adjusted apogee the flight page shows, and it's the one that scores.
How it pays
- To win
- Reach 300.0 m
- Pays
- 350 points to every flyer who makes it
- Once each
- Your later flights go on the leaderboard but don't pay again
- Points paid
- Once we have checked the entry
- Dates
- From 5 Nov 2026
Required altimeters
The flight is checked against the altimeter that recorded it
- Hardware
- Rev 4 or later
- Firmware
- 1.65 or later
- Hardware
- Rev 1 or later
- Firmware
- 2.50 or later
- Hardware
- Any revision
- Firmware
- 1.02 or later
- Hardware
- Any revision
- Firmware
- 1.00 or later
Required flight details
Everything is checked when you add a flight- Your own flightFrom an altimeter on your account, and a real flight rather than a test.
- A D motorAdded on the flight page. The class is the total rated impulse of the flight's motors: D is 10.01 to 20 Ns.
- Single motorOne motor on the whole flight: no cluster and no staging.
- Single stageCounted from the stages of the motors added on the flight page.
- Motor proven by its burnThe total impulse measured from the altimeter's accelerometer and the lift-off weight has to be within 20% of the rated motor, as NFPA 1125 allows.
- Lift-off weightEntered on the flight page.
- Launch siteSet on the flight page.
- Launch date and timeSet on the flight page.
- Launch weatherAdded to the flight once its site, date and time are set. Altitudes here are corrected for it.
- Flown during the challengeOn or after 5 Nov 2026.
Your altimeter works out height from air pressure using a standard atmosphere: the sea-level pressure and temperature in its settings, usually 1013.25 hPa and 15 °C. The real day is rarely standard. Cold air is denser, so an altimeter set for 15 °C reads high on a cold day and low on a warm one, by roughly 1% for every 3 °C, which is about 2 m at 200 m.
So every flight is judged on the height it really reached, we take the weather added to your flight for its launch site, date and time, and recalculate the whole log with it. It's the same adjusted apogee the flight page shows, and it's the one that scores.