Acceptable descent profile?

[bugwubber]

WRA, just wanted to get your take on this- this is a non ballistic recovery rocket. No chute, just falls sideways. Is this slow enough?

HK-A_2014331_129.png (147.28 KiB) Viewed 68 times

[WRA2]

WRA, just wanted to get your take on this- this is a non ballistic recovery rocket. No chute, just falls sideways. Is this slow enough?

HK-A_2014331_129.png

The rule states 33 feet per second at touchdown. Any kind of recovery that achieves that speed is allowed (chute, steamer, wing/glider, tumble, side glider, etc.)

28.95 feet per second would meet the criteria.

All launched parts of rocket which travel over 6 meters (20 feet) in altitude must have a recovery system which limits their descent rate at time of touchdown at ground level to a maximum velocity of 10 meters/second (33 feet per second)

[bugwubber]

WRA, just wanted to get your take on this- this is a non ballistic recovery rocket. No chute, just falls sideways. Is this slow enough?

HK-A_2014331_129.png

The rule states 33 feet per second at touchdown. Any kind of recovery that achieves that speed is allowed (chute, steamer, wing/glider, tumble, side glider, etc.)

28.95 feet per second would meet the criteria.

All launched parts of rocket which travel over 6 meters (20 feet) in altitude must have a recovery system which limits their descent rate at time of touchdown at ground level to a maximum velocity of 10 meters/second (33 feet per second)

Great! Thanks.

[Water Rocket Expert]

Oh no, here he goes getting a record!

WRA2, would my altimeter work for testing descent rate on a unreinforced flight. It is peak altitude but it has descent rate feature.

[WRA2]

Oh no, here he goes getting a record!

WRA2, would my altimeter work for testing descent rate on a unreinforced flight. It is peak altitude but it has descent rate feature.

If you combine it with a good simulator and or video of the flight. You know the peak altitude. If you took video or used an onboard camera (better) you can figure the time the rocket took to descend from apogee to the ground and figure out feet per second from that.

[bugwubber]

Oh no, here he goes getting a record!

WRA2, would my altimeter work for testing descent rate on a unreinforced flight. It is peak altitude but it has descent rate feature.

Well, whether we do or not, in this case I'm more interested in making sure the design conforms to WRA safety rules before I start telling others how to make it.

[Water Rocket Expert]

Oh no, here he goes getting a record!

WRA2, would my altimeter work for testing descent rate on a unreinforced flight. It is peak altitude but it has descent rate feature.

If you combine it with a good simulator and or video of the flight. You know the peak altitude. If you took video or used an onboard camera (better) you can figure the time the rocket took to descend from apogee to the ground and figure out feet per second from that.

So does that mean we don't have to have onboard video, just good ground based video? That would be awesome because the camera I am using right now is too heavy for a 2 liter rocket.

[WRA2]

Oh no, here he goes getting a record!

WRA2, would my altimeter work for testing descent rate on a unreinforced flight. It is peak altitude but it has descent rate feature.

If you combine it with a good simulator and or video of the flight. You know the peak altitude. If you took video or used an onboard camera (better) you can figure the time the rocket took to descend from apogee to the ground and figure out feet per second from that.

So does that mean we don't have to have onboard video, just good ground based video? That would be awesome because the camera I am using right now is too heavy for a 2 liter rocket.

Your question was on how to determine the descent rate of your rocket.

Cameras are required onboard for all competitions except the flight duration:

http://www.wra2.org/WRA2_Class_C_Rules.php

No exceptions.

[Water Rocket Expert]

Thanks! I probably should have looked at the rules first.

[U.S. Water Rockets1]

If you are interested in the descent rate only at the moment of landing, you can also use a reference object in the ground based video. You can see at that frame number the rocket is level with some object of a known height (you can measure it at any time) and then count the frames it takes to reach the ground from that point. The video file will have a set number of frames per second, you can figure out how many seconds it took to travel the known distance and divide to get feet per second.

[Water Rocket Expert]

If you are interested in the descent rate only at the moment of landing, you can also use a reference object in the ground based video. You can see at that frame number the rocket is level with some object of a known height (you can measure it at any time) and then count the frames it takes to reach the ground from that point. The video file will have a set number of frames per second, you can figure out how many seconds it took to travel the known distance and divide to get feet per second.

I know, although I am trying to find average FPS, that is why I am using my altimeter to shorten the work.

[Alien Space Agency]

Wait, PA altimeters are acceptable with descent rate?

[bugwubber]

Wait, PA altimeters are acceptable with descent rate?

You have to have an onboard camera so descent rate can be derived from elapsed time.

[Alien Space Agency]

But logging altimeters are still required, right?

[WRA2]

for our altitude competitions logging altimeters are required for the following classes (A, B, and E). Peak altimeters are allowed for Class D.