Issues with Estes Altimeter in a Water Rocket - Seeking Advice!

[Anonymous]

I recently purchased an Estes Altimeter for my water rocket project, but I'm facing some issues with its height measurement capabilities. Despite my rocket achieving an estimated altitude of 20-30 meters, the altimeter consistently displays 0 meters. I'm beginning to wonder at what altitude this altimeter starts to effectively differentiate heights.

A bit of background on my rocket: It's a homemade water rocket, primarily constructed from PET bottles and corrugated plastic fins, also with a homemade launcher. The nose cone, in particular, is crafted from the front part of another plastic bottle. Due to the smooth nature of the PET bottle material, I found it impossible to drill additional holes in the nose cone itself for air pressure equalization – the drill just wouldn't work on it. Therefore, the only ventilation holes are located in the nose cap.

I'm curious if the lack of sufficient ventilation holes in the main body of the nose cone could be affecting the altimeter's performance? Or is it possible that the Estes Altimeter is not sensitive enough to detect altitudes in the 20-30 meter range?Issues with Estes Altimeter in a Water Rocket - Seeking Advice!

 

[JimByrne]

Strap the altimeter on the outside (maybe near the fins) for one flight.
If it works you need to add vent holes.
If it doesn't work, then it is not going high enough to activate it, or
it is defective.
I have several water rockets and have not yet flown with an altimeter.

 

[Anonymous]

How would you suggest measuring height without an altimeter? Trigonometry with some type of apparatus?

 

[Anonymous]

Strap the altimeter on the outside (maybe near the fins) for one flight.
If it works you need to add vent holes.
If it doesn't work, then it is not going high enough to activate it, or
it is defective.
I have several water rockets and have not yet flown with an altimeter.

The thing is, I live in an apartment, so with the altimeter I walked to the top (it wasn't yet in the rocket) and even at the terrace it didn't seem to detect a change. Yet it markets itself as "Accurately measures rocket model launch altitudes from 0 to 9,999 feet (0 to 3,000 m) and can store up to 10 consecutive flights." Although, on closer inspection in the manual it says "Pressure sampling accuracy of 1 foot below 3300 feet (.3 m below 1000 m) and 3.3 feet over 3300 feet (1 m above 1000 m)." Which means it should detect a difference. Could the problem be that Barcelona is only 14m above sea level? Or that the area is not open enough and I should test it at a park?

 

[mikec]

It's possible that you are simply not getting to the minimum altitude for the altimeter to detect that a launch has occurred. I'm not sure what that number is for the Estes device but many of them don't work below 100-150 feet.

Altimeters work by relative pressure so it doesn't matter how close to sea level you are.

 

[Azamiryou]

It may need to detect a launch (rapid change in pressure) before it will record, so it starts with 0 on the launch pad rather than wherever you turned it on.

 

[Anonymous]

I got it back from a test launch from a few hours ago that go onto a neighbor balcony who was away. It did read that flight, apparently it went 85 m. The thing is I say the rocket and there was no way that thing went up 85 m, probably closer to 20-30 m, though it did displace laterally. Now that I know it minimally works, could the problems from the reading be the holes made? We had not made holes into the plastic because it was too flexible to do with a drill, so we resorted to doing a couple holes into the nose cone of the rocket, which is consequently another soda bottle superior part, therefore we just made some holes into the bottle cap which connect into the space the altimeter is housed. We have now found a way to make some holes in the plastic itself. Would this method provide reliable results?

 

[Art Upton]

Are these holes facing up , or sideways. The holes need sideways "below" the top of the nose cone and you need to find a way to put them in the plastic bottle. Before drilling use a punch to put a dimple in the plastic for the drill to stay put in.

 

[Azamiryou]

apparently it went 85 m. The thing is I say the rocket and there was no way that thing went up 85 m, probably closer to 20-30 m

Is it set for metric? 85 feet would match the observed 20-30m.

 

[Art Upton]

This might work better for you : https://estesrockets.com/products/altitrak

 

[Anonymous]

Is it set for metric? 85 feet would match the observed 20-30m.

Yes, it is set to metric

 

[Anonymous]

Are these holes facing up , or sideways. The holes need sideways "below" the top of the nose cone and you need to find a way to put them in the plastic bottle. Before drilling use a punch to put a dimple in the plastic for the drill to stay put in.

The holes on that launch where facing up, I'm guessing the incorrect measure was due to that

 

[Art Upton]

The holes on that launch where facing up, I'm guessing the incorrect measure was due to that

You can't have holes facing up, it would FORCE air into the readings, not SUCK air out which is what the goal is. As a rocket climbs air gets less pressure and it SUCKs it out of the altimeter chamber.

 

[Art Upton]

Frankly I think you surly would get better results with a water rocket on the AliTrack Triangulation system then an altimeter designed for Black Powder Rocket motors with a launch detect.

 

[cerving]

It's possible that you are simply not getting to the minimum altitude for the altimeter to detect that a launch has occurred. I'm not sure what that number is for the Estes device but many of them don't work below 100-150 feet.

Altimeters work by relative pressure so it doesn't matter how close to sea level you are.

^^^ THIS ^^^

Every baro-based altimeter has a "launch detect altitude", typically 100' or more. A flight doesn't get registered until you hit that altitude... pre-launch samples are typically cached so you can get a full launch-to-landing flight log. Your water rocket didn't get high enough to trigger the altimeter, so your flight didn't log.

 

[BABAR]

Any precautions required to make sure the thing doesn’t get wet?