For altitude events, I assume people use altimeters now?

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At rock bottom size/weight it Altimeter Two (A2) is probably there. That said for just a tad more weight and size, you can get the Perfectflite PNUT. A bit more pricey (+$15), however it has a boatload of flexibility. I use both so I have no bias. The A2 is painfully simple to use/integrate. The PNUT is just a bit more technically advanced however requires you to come up with a suitable mounting schema.
 
Al, the PerfectFlite Pnut is the same price as the AltimeterTwo. :-(

What is the difference between them? I could not find a comparison review online. Can you take a photo of them side by side?

I am leaning to the Jolly Roger since it seems idiot proof. That doesn't mean it won't outsmart me but at least I have a fighting chance! :p
 
What I liked about the Pnut is that it is a recording altimeter. You can download data from the Pnut and do whatever you want with it. The Jolly Logic products just report data blinked to you on the LCD. Another feature that I like about the Pnut is that it beeps so that you know that it is still ready to launch when it is enclosed in the rocket. Jolly Logic products don't do this.

I don't "mount" the Pnut on a "sled" a la HPR style altimeter bays. I usually pack them in a payload compartment with a little loose tissue. I have flown them "naked" like a Jolly Logic with no problems.

The tiniest altimeter that one can easily obtain is the Altus Metrum. I don't have one of these so I can't tell you much about it.

Check the back of the Pink Book to see what devices are contest-certified, and which ones are qualified for record-setting.

Brian - check the mfgs for dimensional info!

Altimeter 2 - 12mm x 16mm x 49mm 6.7 grams
Altimeter 1 - 12mm x 16mm x 49mm 6.7 grams
Pnut - 11.4mm x 15mm x 63.5mm 6.5 grams
Altus Metrum - 6.4mm X 14mm X 18mm 1.9 grams

Some clubs still use theodolites. Some do not. Some, like MTMA, do both. It's determined by whatever the CD and the host club feel like flying. It is very difficult, or at least, inconveniently cumbersome for a host club to set up and use theodolites when there are only a few contestants.

-W
 
Based on the gnashing of teeth and 'comments' heard before and during NARAM-54, many hard-core long-time, NAR competitors do not like using on-board altimeters for altitude events. :eyeroll:
 
Based on the gnashing of teeth and 'comments' heard before and during NARAM-54, many hard-core long-time, NAR competitors do not like using on-board altimeters for altitude events. :eyeroll:

Not completely true, at least, not from my experience running several regional meets over the past few years. Not even as a hard-core, long time competitor. On the various forums around the net you can read all about the wailing and gnashing of teeth, but in the field among folks who do more comp flying than comp posting, it's a different story. And why not like them? They work. They're fun. They're here to stay. :)

-W
 
Does anyone know if the new ESTES altimeter has been approved by NAR yet??
 
Based on the gnashing of teeth and 'comments' heard before and during NARAM-54, many hard-core long-time, NAR competitors do not like using on-board altimeters for altitude events. :eyeroll:
Real altitude is measured by sweaty, sunburned men and women using theodolites! I did it for years, now I don't know what range duty to do :(
 
Based on the gnashing of teeth and 'comments' heard before and during NARAM-54, many hard-core long-time, NAR competitors do not like using on-board altimeters for altitude events. :eyeroll:

Up until the last several years there was a lot of disagreement as to the accuracy of many altimeters and also a feeling they were so expensive as to price most fliers out of using them.

More recently most of the commercially-available altimeters have become quite reliable and consistent so the accuracy objection has largely been made moot, and prices for basic models have come down to the level of a typical MPR kit (or in some cases a pack of motors), so the price hurdle has reached a point of not irrelevance but general acceptance.

Plus as many have observed visual tracking is becoming more and more a lost art -- fewer and fewer people have much experience with it, and even fewer clubs have the equipment necessary to do it properly. Thedolites can be bulky and expensive -- clubs could buy a 6-pack of altimeters for the cost of making a couple of good thedolites.

In a way I am kind of sad to see visual tracking fade out because there is no doubt it was ONE highly educational aspect of model rocketry -- any kid who understood the basics of 2- or 3-station tracking was already about 3/4 of the way to an A grade in high school geometry -- but it is part of the technological evolution of daily life. We used to write letters or send telegrams, now we send emails and IMs.
 
The NAR has established a whole new class of records for altimeters. Be aware that to set a record you will need to fly one of the data-logging altimeters, like the p-nut, altus metrum, or adrel.

Photos of the newest Adrel and battery on a scale. Note that those weights are in Grams, not ounces. Also note that the Adrels will fit in a 10 mm tube.

IMG_4560.jpg IMG_4562.jpg

Photo of the old, "fat" Adrel.

IMG_4561.jpg
 
.... as well as the MicroPeak altimeters. Much lighter than the above mentioned altimeters.

The above mentioned Altus Metrum is the MicroPeak altimeter you refer to. I have no experience with those altimeters, yet.

I have heard (from actual Adrel users) that the Adrel is troublesome to obtain and notoriously finicky and unreliable. But since the Adrel is the only altimeter approved for FAI altitude events, that's what all the FAI fliers are forced to use.

-W
 
Yes, the Adrels can be very finicky. I haven't tried the newer version that Gus posted, but one of the updates to the firmware was to make it less susceptible to false triggering while still on the launch pad. We've even had problems with the MicroPeak models when they would stop recording when the unit would accidently assume that the staging dynamics represented apogee.
 
Also note that, at least for now, neither the Altus Metrum MicroPeak nor either of the data-logging Adrels is currently on the NAR Appendix G list (the list of approved-for-competition altimeters). So at the moment the lightest unit that can be used for setting NAR records is the PerfectFlite Pnut.

I'm looking forward to seeing the others on the list....hopefully soon.


I guess it's time for me to try one of the new Adrel-BMPs. I see they are now available for order.

Gus, does the software for the BMP work with Windows 7 or later without having to go around the signed-application business?
 
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Using theodolites for altitude tracking is not an art form nor is it rocket science. It does require good eyesight but any sharp eyed teenager can pick it up after a few launches. Very accurate theodolites can be built in your average highschool shop class for very little money. The problem with theodolites, they are a bit bulky, it's another item for the club haul and store and the limited interest in contest flying makes manning tracking stations problematic especially for smaller clubs. Altimeters make altitude contests easy even for the tiniest clubs.
 
The issue of "available altimeters have become quite reliable and consistent so the accuracy objection has largely been made moot" is going to become more significant. Barometric sensors or integrating accelerometers will need to be calibrated, to allow unit to unit measurement comparisons. Proof of this is shown in the recent issue of Rockets magazine, volume 7 issue 6, page 17.

NAR or Tripoli is probably going to have to establish acceptable tolerance standards for altimeters range of output values to be considered record setting.
 
The Micro Peak altimeter was approved for contest use last week. Keith from Altus had responded to an email from me and it seems like he's really doing a good job of tweaking the firmware for the best results. We've all had problems with false launch detect with a number of the smaller altimeters and Keith has made a number of changes to eliminate this problem.
 
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