Altimeters - Love 'em or leave 'em?

[dr wogz]

Hi All,

Curious to know:

Are Altimeters important? Do you all use one, is it just a novelty, unless you really really need to know what altitude is reached (Contests, scientific reason / research, personal wish, developement research, etc..)

I'm talking a simple altimeter, not a 'required' HPR dual deployment type. Just a simple altimeter to recoard peak altitude attained.. It'll be for my MPR birds..

good / bad suggestions?

Curuious about the PerfectFlite Alt15K/WD in particular..

 

[Daedalus]

I have the Alt/15k - tells you how high it went and records 100 samples/ second for the duration of the flight. Doesn't control deployment so is a (very interesting) toy really, then pretty much all rocketry stuff is toys - how many people actually do 'real' scientific research?

All that said the Perfectflite kit is excellent quality kit (I have the Alt/15k and 2 MAWDs). I also have the G-Wizz LC (not the deluxe) - deploys a parachute but doesn't compute an accurate altitude, I would not recommend one of those.

 

[phaar]

If you get an altimeter, you will only want to put it in a rocket you REALLY trust. If not, you will end up blowing a quick $70. And trust me, it does not feel good.

 

[rstaff3]

Originally posted by Dr Wogz
...I'm talking a simple altimeter, not a 'required' HPR dual deployment type. Just a simple altimeter to recoard peak altitude attained.. It'll be for my MPR birds..

Curuious about the PerfectFlite Alt15K/WD in particular..

Reasons to get an altimeter:

1. to eject chutes (single or dual deploy)
2. to airstart (at launch and/or at burn-out)
3. logging peak alt (for contest or personal gratification)
4. logging entire flight profile (alt, vel, accel, motor thrus, Cd, etc (not available on most)
5. why do it? because you can!

They are either required or not. You either want this data or not.

Consider the rocket and the launch site. Crashing an alt or having it out of reach in a tall tree are both bad.

 

[rocketsonly]

how many people actually do 'real' scientific research?

I did! Last year's science fair project I earned an A+ with my Perfectflite altimeter. Now I always put altimeters in my rockets just because I like the feeling of a rocket carrying an electronic payload I hope to soon by a dual deployment altimeter as well.

I highly recommend them if you love electronics!

 

[DynaSoar]

Originally posted by Dr Wogz
Hi All,

Curious to know:

Are Altimeters important? Do you all use one, is it just a novelty, unless you really really need to know what altitude is reached (Contests, scientific reason / research, personal wish, developement research, etc..)

I'm talking a simple altimeter, not a 'required' HPR dual deployment type. Just a simple altimeter to recoard peak altitude attained.. It'll be for my MPR birds..

good / bad suggestions?

Curuious about the PerfectFlite Alt15K/WD in particular..

I haven't bought one yet, but I've been researching them so I get what I need.

I care about flight profile: what speed at what altitude and peak altitude, and any "bumps" in the profile, such as max Q when going Mach+. I want to be able to dump it to computer. I want to be able to incorporate GPS. Most of all, I want it to be accurate.

I plan to get the Ozark ARTS, particularly for the accuracy. It handles the profile by both barometric and acceleration measurement. It'll do everything I want, and is the best I've seen for my primary need. It can do staging and dual deployment, in case I ever want to (don't plan to yet). It's not the smallest or lightest, but when I do things that I need electronics for, those won't be an issue.

 

[solrules]

Originally posted by Daedalus
how many people actually do 'real' scientific research?

Ooh! ooh! Gotta chime in. I use the data I get from my ARTS for calculus class, interestingly enough. It shows how differenting position to get velocity is a very bad idea. Differentiating tends to bring out the error in data while integrating acceleration to get velocity tends to smooth over the erros in data. Ever check some MAWD raw data? It tends to go

120
120
127
130
130
130

that gives really bad velocity approximations.

Of course, I use the ARTS for dual deployment. Not a very cheap one at $180 either. But very interesting, you can get more data than you can shake a stick at. It is rather large too.

back on topic, I never would get an altimeter to do nothing except report altitiude. Seems like a needles waste of money if you happen to lose your rocket.

 

[Zack Lau]

Nartek Gold involves some scientific research--measuring the Cd of a rocket you designed. I used an altimeter to see how my rocket did with A10 and A3 engines. At the time, these were the smallest engines that seemed feasible with altimeters--but there are smaller altimeters now.

https://www.nar.org/NARTREK/

 

[Thrasher]

I switched to using altimeters. I like knowing how high they really went and I like the main 'chute opening at 300', so I don't have to walk or lose my rocket. I use the Missile Works RRC2 altimeter ($90).

 

[Daedalus]

Originally posted by solrules
Ooh! ooh! Gotta chime in. I use the data I get from my ARTS for calculus class, interestingly enough. It shows how differenting position to get velocity is a very bad idea. Differentiating tends to bring out the error in data while integrating acceleration to get velocity tends to smooth over the erros in data. Ever check some MAWD raw data? It tends to go

120
120
127
130
130
130

that gives really bad velocity approximations.

OK so thats real science. I knew a few people would be using them for science - just most of us don't. Yes, I have looked at my MAWD data and it is pretty rough for velocity calculation wiithout some sort of rough and ready smoothing - and that doesn't help too much with getting good velocity approximations.

I guess I need another altimeter / flight computer with acceleration logging on it. Perhaps now I have decent recovery altimeters I should look at designing my own flight computer - just for the hell of it. Definitely a winter (or later !!!) project.

Originally posted by solrules
back on topic, I never would get an altimeter to do nothing except report altitiude. Seems like a needles waste of money if you happen to lose your rocket.

but great if you want to record altitude for competitions with small motors - the Alt/15k saves a few grams over the MAWD in an already sub-optimal rocket.

I have an alt and radio tracker in a 24mm model - flew it at the weekend to 981 ft on a D12. Now that is way over weight but it was for a tracker test and Cd calculation ready for bigger motors. Didn't need the tracker and only recorded altitude. Yes it would be a waste of money but I need the data to validate the design so a necessary risk. For maximum altitude I would need to take a bigger risk by dropping the tracker and using the alt/15k rather than the MAWD.

 

[Austin]

Using altimeters brings you into another realm of this hobby, electronics. It's a good way to introduce you into the basics of electronic flight, be it just for altitude or delving into new frontiers such as dual deployment or flight recording. Either way, it is a good way to introduce you to this side of the hobby and it's only a beginning. It can lead you into more advanced electronic control, such as Flight recording, Telemetry, RDAS, GPS, Video recording, staging, timers and timing, air starts, Video transmitting, Remote control deploy, dual deploy, backups/redundancy and more.

Techniques used and learned would include use of various types, shapes sizes and styles of switches, safety in arming, shunting, etc... the list goes on. This all may seem a bit overwhelming, but taken one step at a time, it can be very rewarding. That is the beauty of our hobby, there is always something new to do or try!

Good luck in your choice and keep us up to date.

Carl