Suggested Altimeters for Competition

[NWIC-SC]

Hi all,

According to rule 8:
Rocket must carry onboard a commercially produced recording ("Logging") altimeter to document the entire flight on a Time vs. Altitude Graph to nonvolatile logging memory or telemetry to relay the altitude information to a remote logging receiver.

What are your recommendations for altimeters that meet this rule requirement?

Thanks - Gary

[Daan.[D&P]Rockets*]

We are using a Perfectflite Alt 15 K. A very lightweight altimeter and it beeps out how high the rocket went.

[WRA2]

Hi all,

According to rule 8:
Rocket must carry onboard a commercially produced recording ("Logging") altimeter to document the entire flight on a Time vs. Altitude Graph to nonvolatile logging memory or telemetry to relay the altitude information to a remote logging receiver.

What are your recommendations for altimeters that meet this rule requirement?

Thanks - Gary

Hello Gary,

We have never posted a list of altimeters because we do not endorse products and there are lots of different manufacturers located all over the world. The altimeter can be any commercially produced. No scratch built, kit, or altimeters produced in small quantities (preventing someone from mass producing home built altimeters in an attempt to qualify as commercial)

For some of our competitions we also require that the altimeter "log" altitude vs. time. This provides data for altitude during the entire flight and not just the apogee. We require commercial altimeters to prevent tampering. Someone using their home made altimeter would have control of the software and could conceivably "adjust it" to read higher. With a commercial altimeter the software is inaccessible to the team.

The best bet would be to find a locally available altimeter and post it to the forum if it is new before you buy.

Please include the manufacturer name, their website and model number and the WRA2 competition you plan on entering. We will then provide everyone with a determination if it is allowed for the competition.

Several of our competitiors have stated that they use various models manufactured by Perfectflite.

[NWIC-SC]

Thanks to the both of you for your useful replies. I now have a baseline to do some comparison "shopping"

I'd like your thoughts about Apogee's "How-High SP" Altimeter.

http://www.apogeerockets.com/How-High_altimeter.asp

We want to eventualy try for any of the altitude records once we get many things, such as reliable recovery, consistent rocket building, under our control.

Again, thanks - Gary

[WRA2]

Thanks to the both of you for your useful replies. I now have a baseline to do some comparison "shopping"

I'd like your thoughts about Apogee's "How-High SP" Altimeter.

http://www.apogeerockets.com/How-High_altimeter.asp

We want to eventualy try for any of the altitude records once we get many things, such as reliable recovery, consistent rocket building, under our control.

Again, thanks - Gary

This would be considered a Peak altimeter. It displays only the highest that the rocket flies and not the entire flight. It would only eligible for some of our competitions. If you are interested in eventually competing in the single stage or multiple stage world record classes you would need one similar to this one:

http://www.apogeerockets.com/altimeter.asp

Altimeters of this type need some kind of cable to connect to a pc to download the flight data similar to this one:

http://www.apogeerockets.com/altimeter. ... ansfer_Kit

You can even get better prices if you buy straight from the manufacturer:

http://www.perfectflite.com/

[WTF]

I want to know why the world record rules does not take the accuracy specification for altimeters as part of the validation. I think you should make the teams submit the accuracy along with the record and the official record would subtract the accuracy from the reading. If the altimeter is accurate to +/- 1 meter and the rocket flies 500 meters then you put the record at 499 meters. If you don't do that then someone with a different altimeter with +/- 3 meter accuracy might get an advantage because their rocket may have gone much less high than the altimeter reads.

[RaZias]

I know that the guiness book for the speed record in the ground (I am talking about the supersonic car) stated that to have a new record the car should pass over the present record by one percent of it.

I agree with this, imagine what is a 1 meter diference between a 2010 record and a 2011 record...
If 1 meter is ok, then the rocket should bypass the precedent record (even by one meter) in the 2 flights in a 2 hours time window.

[The Mooseheads]

I want to know why the world record rules does not take the accuracy specification for altimeters as part of the validation. I think you should make the teams submit the accuracy along with the record and the official record would subtract the accuracy from the reading. If the altimeter is accurate to +/- 1 meter and the rocket flies 500 meters then you put the record at 499 meters. If you don't do that then someone with a different altimeter with +/- 3 meter accuracy might get an advantage because their rocket may have gone much less high than the altimeter reads.

Actually, this eventuality was part of the consideration for the 2 flight average requirement for the record. Some of this was intended to eliminate the possibility of a meteorological phenomena from causing a record, and some was intended to prove that the rocket was not purpose built to set a record through self-destruction. It was also used to statistically reduce any errors introduced by the measurement error inherent in any record.

The method was adopted because it is neutrally biased. It neither favors or penalizes the entry. Simply subtracting the error resolution of the altimeter from any submission is biased negatively. In other words, if your altimeter read on the low end of the reading for a submission, you would be doubling the error for that reading using this method. It's already off by the error range and you're subtracting the error range a second time. Hence, a negative bias.

The actual rules are neutrally biased, and use statistical probability to cancel out errors.

No other record holder or proposed rules set in the past has ever considered the error band at all. This kind of innovation thinking is the hallmark of the WRA2 rules.

[WTF]

That sounds logical. I think that's fair enough. thank you.

[U.S. Water Rockets1]

Don't forget that the rule requires the use of logging altimeters and you can easily see from the graph if there was a glitch or anomaly in the peak reading. Deploy systems sometimes cause the barometric sensor in the altimeter to read a spike in altitude. A hard landing can also lead to a false peak altitude reading. The rules eliminate this type of error.