G37 to 8241 feet

[Chad]

JamesR wrote:

Right now, there is a huge internal debate in the TRA Records committee going on over barometric altimeters for any altitude records to begin with. With all sorts of discussions going on about the standard atmospheric model, baro sensors, temperature compensation, etc. No one is particularly standing up for baro OR accelerometer based altimeters and most of the discussion seems to lean in the direction of GPS based altitude determination and requiring 4 satellites locked during the flight as well as providing the full raw GPS data stream rather than just an altitude number in order to set a TRA world record.Warren

Hopefully TRA and other certifying bodies are looking at what has been done in aviation. Balloon, glider, and other aerial records have been well regulated for decades. Although 5 years ago everything went GPS, we worked with pressure altitudes successfully. Each time you had a record with a pressure barogram, you had to have it certified within one month afterward. The actual vs. reported altitude was put into a look-up-table and you did a simple linear interpolation to get your actual altitude.

With G-impulse on up, there is ample weight (though not diameter) to accommodate the bulkier GPS electronics. But clearly for now, low impulse records will rely on pressure altimeters. For altitudes below a few thousand feet, the difference between the standard atmospheric model and the actual atmosphere is only going to be a few tens of feet (don’t launch on a high pressure day!). But at 10,000′ AGL the difference could be 500′!

The other issue with pressure is port location. I could easily devise a venturi around my ports to generate an extra 0.01 bar of suction.

Do GPS units now normally get 4 satellite triangulations at apogee? Seems like a lot to ask from a little unit that passes through mach a few seconds before (and the national security imposed GPS speed limit). That seems reasonable with a ground beacon, and a lot more accurate, but certainly adds to the expense.

[Chad]

The last thing I want to do is stifle any innovation when it comes to new products and designs for rocketry. We definitely need new, smaller, accurate, affordable deployment altimeters – there are just too few choices out there.

That being said, I want to address the RSO/LCO witness request made earlier. It got me thinking – “what if that were me?” I think I would have trouble verifying an altitude a week later based on an email. I just would not feel comfortable putting my name down as a witness in that case. Maybe I’m a bit old fashioned but I like the way it’s done now……Someone walks up to the LCO table, smiling, with a beeping rocket in hand. This is what I have no qualms about witnessing.

For what it is worth, Mike found the rocket and dropped it off at the launch site when I was there hunting for lost rockets. So there was a chain of custody of the rocket up until the point the altimeter was downloaded. These are really good ethical and procedural questions, but hopefully there is a rule book with this written down that provides a clear answer

[Warren B. MusselmanModerator]

Chad, that is one of the things that TRA’s new records committee is working on. Up until recently, TRA records were largely the province of Tom Rouse and his judgement ruled all. A few recent controversies, including one of Adrian’s record applications, caused him to resign from the position and a new committee has been formed with Erik Gates I believe in charge. At the moment, no record applications for flights over 25K are being accepted without raw GPS data showing a minimum of 4 satellites locked. Pressure altitudes are being accepted below 25K though that may not last long according to rumor.

As for barometric altitude in the aviation industry, those altimeters are calibrated and traceable to NIST standards. This is not true of the run of the mill rocketry altimeter. I think that having individual altimeters calibrated to NIST traceable standards should be a baseline requirement for altimeters used for altitude records,

Warren

[James Russell]

from what I understand the TAP will be assisting in some of these issues and applications of 25k but the contents chair will not except any data other then GPS 30k and above, at lest that was the last I had heard at LDRS a month ago. They are also working out were if one is going to tray to set a record they will need to request an approved altimeter that will be owned by TRA that will be shipped to them with a fee or a deposit. They will own maybe 12 of them and will send them out as needed and all records will be with the same brand and same units to prevent any issues (they hope). This is not set in stone but what is being looked at they still need to agree on a brand or see if someone would make one just for this use.

[James Russell]

MrEd wrote:

On a related note, what if Bdale finds his L3 bird and simply emails his TAP a digital photo of the recovered rocket, would that count for a successful certification? I hope not, but it seems like it’s a related issue.

Quote:

Ed, I do not think it is an issue at this point, he is looking at building a new rocket and has a reword out for the first one. The NC was out side the waiver based on what I understand the waiver to have been at that time. not sure if it was blown out on the ground or if the main came out a lot higher then he had expected. He is not concerned about the cert though it would have been nice to have only needed to do it once he totally understands. It is always a bummer to loose a rocket but a bigger one when it was a cert rocket and even bigger that it was on your cert flight. For the record I would need to have a good idea were it was found and why it was not seen and recovered the same day. If it is found I would need to see the rocket in person and if a TRA cert need to discuss it with the other TAP before a decision would be mad. If NAR I again would need to see it and it also would need to be inspected by another NAR member to see if all is ok and it can qualify for a cert flight. All the same questions in the post flight will need to be answered and if qualifies then I will sign.

there is nothing saying it has to be recovered same day but it is also up to the judgment of the TAP or L3CC and if it was a couple of days no big deal but a month is to long, and how would you be able to verify the landing location, did it get dragged or did it deploy at a higher altitude.

[AdrianParticipant]

Some food for thought:

The “ideal” situation of presenting a beeping rocket to an LCO has a fundamental limitation:

There’s no way to prevent deployment or other transients from corrupting the data. If I had flown a peak-reading altimeter in this G37 shot, it would have read over 9000 feet, because the shock cord pulled the av-bay up a little bit when it went tight, causing it to expand a little and a false maximum altitude to be read. Because I could read the graph, I can see that I should ignore the data right after the deployment. But with a peak-reading altimeter, we would have no clue that that had happened, through nobody’s fault. I think that if it weren’t for the history and precedent of using peak-recording altimeters, we would have a consensus that they’re not sufficient for recording altitude records.

And even a beeping rocket presented to the LCO doesn’t prevent someone from cheating if they are determined to cheat. If someone launches a rocket out of sight, goes out with a transmitter and comes back with a smile and a beeping rocket, how does anyone know that the altimeter wasn’t swapped out? If that person were questioned and accused about it, he would rightly take offense. Sportsmanship, honor, honesty, and our own reputations are the only things preventing anyone from cheating, with any altimeter.

I don’t think twice about leaving car keys, radios and computers laying around the prep area, because we’re a small community and I trust my fellow rocketeers. So I’m a little taken aback by the assumption that people are going to cheat on records if it is “easy” to do so. I know that people aren’t accusing me specifically, but even in the hypothetical case I don’t really get it. I think that questioning about the details of how a record was measured is fine, if we’re trying to discern any accidental errors or confirm surprising results. But we should assume good faith on the part of our peers until proven otherwise. Anyone can cheat, using any altimeter.

There are some other specific questions that I’d like to respond to, but that will have to wait for now.

[SCOTT EVANS]

Adrian, two concerns, you are the designer and programmer of the device, sending a file or posting your charts do not allow someone to verify your altitude. I am not questioning your honesty but I am questioning your participation.

For club level we have had a rule that any altitude needs to be verified by another member. I know of at lest 1 that was not and it was never questioned. At a club level it is more of a friendly competition but at the national level it is not so much.

Nothing against you but I do not feel that a manufacture of an altimeter should compete for national records using his own flight computer and data that you can tweak.

Just my opinion,

So……
Whats to keep me from building 2 identicle Rockets, or 2 identicle ebays. Launching one, and bringing back another with the burnt moter, and a comercial altimiter that just came out of a vacume chamber or what ever.
If a guy wants to cheat, he can!
From what I have found, I dont really trust any of electronics we buy to be really all that acurate.
The records on the web are a best guess of all, hopefully, trying to be as honest as they can, using $100.00 doller pieces of equipment.
Most pilots looking at this (and there are a few) like me, look at it as well…… Its a hobby…its fun…. and my life doesnt depend on them.
I think he should submit it.

Scott e

[Doug GerrardParticipant]

Whats to keep me from building 2 identical Rockets, or 2 identical ebays. Launching one, and bringing back another…

I hope the person certifying you remembers this… 😉

Doug

[Anonymous]

I’ve tried to stay out of this as I have an inherent conflict of interest. Since no one else has brought these items up, I’ll toss them into the mill. I have a question and a comment.

First, my question – was this rocket really found 3 miles away (per the original post over in lost and found?) If it was indeed that far away, how does a rocket that goes to 8K (or 9K or even 10K) land 15,000′ feet downrange when it was under a streamer? Either it went a LOT higher, allowing it to land way over there, or it took off on a pretty wicked tangent (meaning it wouldn’t have gotten nearly as high). I would say mathmatically it is pretty much impossible to go to 8K and land 3 miles away with a smallish streamer.

Next, my observation. One of the TRA TAP posts listed the AOO, or “area of operations” for the sites around the country. That post said NCR’s AOO is 3 miles in diameter and 20,000′. That is a 1.5 mile radius. Anything that lands outside of that cylinder is disqualified. I know this because TRA DQ’d a high profile M shot earlier this year at Black Rock. They have a much bigger AOO than NCR, but the rocket landed 11+ miles away.

Until very recently I was unaware we had such a narrow cylinder. Bottom line, if that figure is correct, then anything that lands 1.5+ miles away is disqualified. TRA has enforced this quite stringently.

Joe, perhaps you can clarify our AOO? is it 3 miles radius or 3 miles in diameter? In any event, it would still be tough to land that far downrange, IMHO.

PS if we do have a 1.5 mile radius, then my L record is not viable – it was recovered 2.5 miles downrange.

[James Russell]

I guess you are not seeing the point I am trying to make. I think it is a conflict of interest and think that TRA/NAR should not recognize your records for the fact that you are a manufacture.

I am not an engineer, maybe that is why I do not understand that you need to analyze and interpret data that an altimeter gives you and you can not just use the data that it gives you straight off. That tells me that there is something wrong with your computer and you need to continue working on it. You need to make it to were it is straight out of the altimeter the altitude that you get is what you get. If it is not accurate that way then you need to update it and work on it and collect data. Fly it with other devices like GPS and other baro and accelerometer based computers. Collect more data not manipulate it to what you want or what you think it should be and make it be user friendly so no one needs to interprete the data and manipulate the data. The data you have is questionable and not verifiable any one else would be just looking at what you say and nodding their head.

the more I read your posts here and other places I question your data, I really would like to see you fly a bigger rocket with several other altimeters and GPS units with out and smoothing or interpretation of the data, just straight up head to head with some of the industry standards like RDAS, Missile Works, PerfictFlite, G-wiz and a GPS like Beeline. Fly it high, low fast and slow, look at you data and publish the data. Better yet have someone independent do it so that there is no playing with the numbers. That might be a real good way of proving your electronics and could really help you work out your firmware/software.

[Author]

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