G37 to 8241 feet

[AdrianParticipant]

I may have a somewhat different take on the record list than some people. Some view it as a contest like the upscale contest, in which it’s possible to exclude some people from participating. I view the list as a place to record what have been the highest undamaged flights for each motor class. Every flight that is recovered safely can either be proven to be the highest safe flight that has ever flown, or it can’t. And if someone brings forward proof that they had the highest flight, then either they really had the highest flight, they made an honest mistake, or they are a liar. If a flier who broke the record didn’t lie or cheat or have an inaccurate reading, but that flight isn’t on the list, it doesn’t mean that the flier didn’t break the record, because his or her flight certainly did. It’s just a failure of the record list to accurately record the highest flights.

From this perspective, the only reason to exclude manufacturer’s flights from record lists, when they use approved altimeters with valid-looking data, is if there’s reason to believe that they cheated. Not that it’s possible for them to cheat, but that they did cheat. This is why I took it personally at first when Tom Rouse originally refused to put my record-breaking F flight on the TRA list. I interpreted the ruling as saying that no manufacturer can be trusted to submit an honest record application form, a policy which I found to be insulting and absurd.

In the meantime, I’ve come to understand that some people view the record list as a contest, with rules for participation that mean that a record-breaking flight from an excluded participant just doesn’t count. So I don’t take it so personally any more. It’s really just a fundamental difference of opinion about whether the record list is a contest from which some people are ineligible to participate, or an attempt to document what has actually been achieved in high rocket flights. The gatekeeper for each type of list has to decide what kind of list they intend to maintain.

[slipstick]

I had the same thoughts about a conflict of interest, but on the other hand technology normally gets driven by a person which can not acomplish his desires when other alternatives are not available.

Be that as it may, after trying to figure out how to make the Parrot work, with little success on my part, I find it too complex to use for getting a simple altitude, and I just don’t want to spend time playing with a laptop in the field. I like the fact that the design is so small, but I would LOVE to just be able to turn it on, fly it,and get instantaneous feedback, and if lost and the battery dies, have the altitude recorded so I can find out what it was.

So, beeps would solve my problem and the concern of getting a validation at the RCO table. I am fairly certain that the NAR would not approve of getting a result after a recovery if the rocketeer went back to the pits first. They were real anal at NARAM 50 to insure they saw motors before they were placed in the rocket (with the initials of the check-in folks) and afterwards, and recorded the serial numbers of weighted payloads and eggs. Rockets had to be returned to the RCO table before the end of the day (8:00 PM) to count as a new altitude or timed duration record. The rocket had to be dissasembled in front of the RCO, to verify the parts as well. One altitude record was taken away from an A division young lady because her father put it on the rod and launched it, then recovered it all while she was doing range duty.

So rev 3 needs beeps to be readable while the rocket is still intact… …for me at least, but also to eliminate concerns of others and to improve its future marketability.

[slipstick]

As an afterthought, I proposed in my R&D entry at NARAM 50, that for the NAR to accept altimeters for record attempts, to get rid of the need for theodilites, that a pressure chamber be present at a meet, and every altimeter compared to a ‘gold standard’ altimeter for that day. Any percent of variance to the standard would be added or subtracted from the altitude reading to establish the actual meet results. Competitors would have their altimeter serial numberd, calibrated with its offset and approved before competing at that meet, or season.

[Warren B. MusselmanModerator]

Adrian, I do want to ensure to ensure you don’t take any of this discussion personally – at least on my part. I have never thought cheating was even a part of this discussion, at least as far as you are concerned.

As I’ve said before, I believe your altimeter has a much better chance of being more accurate than most of the commercial units out there – certainly more so than any I own.

That said, the lack of instantly readable results is probably the biggest obstacle you face from a variety of perspectives:

1) While it’s great to have downloadable data, the lack of instant readability post-flight will cause problems such as Mike Konshak relates above for NAR contests and for other contest environments. The downloadable data is great stuff, but the download/post-processing cycle is viewed askance by some as to prone to manipulation – not necessarily by you, but the process doesn’t conform to chain-of-evidence standards as the results require interpretation and possible corrections based on the totality of the data.
2) Level playing field issues – far from everyone is capable of designing and manufacturing an altimeter. A number of folks I’ve talked with are very taken with the idea that all altitude records be flown with the same model/brand of altimeter or even as James discussed, the same set of TRA-owned and certified altimeters. I personally find the logistics of that somewhat daunting, but the sentiment is definitely there.
3) I’ve also heard the complaint that the Parrot is an unfair advantage due to its light weight and lack of a heavy external battery when compared to the average flyers’ Missileworks or Perfectflight or Adept with an external battery bothers them.

All in all, I’d like to see the Parrot evolve a bit – absolutely keep the accelerometer, rechargable battery, downloadable data and the small size and weight… but some sort of direct read-out that can be turned over at the LCO table immediately after flight without a laptop is a necessity for acceptance in contest use.

Warren

[slipstick]

3) I’ve also heard the complaint that the Parrot is an unfair advantage due to its light weight and lack of a heavy external battery when compared to the average flyers’ Missileworks or Perfectflight or Adept with an external battery bothers them.

Actually this is the differentiator that makes the Parrot so attractive to fly, in that it fits in an 18mm tube and weighs so little. This is not unfair, by any means, its an evolutionary step in progress and technology and just pushes the market in a new direction, and increases the possible acceptance of use in other venues. No one wants to fly the exact same thing and manufacturers that don’t come up with competitive versions will lose out (assuming the market is there). If weight and size are the main criteria, then the perfectflight would be unfair when compared to missleworks and Adept.

[AdrianParticipant]

Thanks, Mike and Warren, for the constructive feedback.

Mike, help is on the way in the form of a PC interface program that Jim Yehle has been kind enough to provide, which will simplify the downloading and interpretation. It’s about 1 software rev away from me advertising that Hyperterminal is no longer necessary, and Excel is optional. It’s a few revs away from also eliminating the need for Excel entirely.

While an altimeter-derived peak altitude readout would undoubtedly simplify an altimeter’s use in contests, the validity of the peak is really questionable. The very flight that started this thread would have a reported altitude of about 9050 according to a peak-readout altimeter, rather than 8241. Why should that be o.k.? Look at the graph again on the first page. The post-ejection dynamics induced a pressure in the av-bay that was lower than ambient. And this isn’t the first flight I’ve seen this behavior. If the altimeter doing the peak recording is the same one that performed the ejection, it can be programmed to ignore any altitudes after it starts flowing current to the deployment charge. But that’s definitely not the case for an Alt15k (which is accepted for records but doesn’t do deployments), and I don’t know if that’s how the other altimeters are programmed. Also, when two altimeters are flown together, one may fire a charge while the other is still recording the peak. A human reading a graph can correctly interpret the true peak altitude better than an altimeter will ever be able to. Not to mention the issue of ambient temperature compensation, which would also require an off-altimeter implementation if the community ever decides it wants to improve its record standards to be more accurate than about 10%.

As an afterthought, I proposed in my R&D entry at NARAM 50, that for the NAR to accept altimeters for record attempts, to get rid of the need for theodilites, that a pressure chamber be present at a meet, and every altimeter compared to a ‘gold standard’ altimeter for that day. Any percent of variance to the standard would be added or subtracted from the altitude reading to establish the actual meet results. Competitors would have their altimeter serial numberd, calibrated with its offset and approved before competing at that meet, or season.

That would certainly work to eliminate questions about altimeter calibration. A test rig that would be adequate for this would cost about $250 for a reference pressure transducer. My setup cost about $500 additional for a pump, chamber and vacuum relief valve so that I can hold the pressure steady. There are probably cheaper ways to do it if a steady reference pressure isn’t necessary. But before long we’ll be seeing relatively cheap and small altimeters with factory-calibrated digital sensors that will eliminate the calibration issue altogether. If the spec accuracy is to be believed, these pressure transducers are as accurate as a reference gauge over a wide range of sensor temperatures. That’s what I had in my prototype last January that I never got around to developnig. But for an accurate altitude, you still need to eliminate deployment spikes and compensate for ambient atmospheric temperature.

[slipstick]

Adrian, In your model rocket configurations, the altimeter is in the same envelope of the airframe so it sees the deployment charge and is directly affected by it. Would the reading be more accurate if it was isolated from the charge by being in a payload, so that it was only reading outside pressure?

Although that adds a little weight and length to the record attempt, it might prevent the anamonoly from occuring. I don’t know much about this, so if I am off base, forgive me for my ignorance. If this is a true assertion, then that would help ‘sell’ it to the sanctioning bodies.

[Murdock]

Adrian, In your model rocket configurations, the altimeter is in the same envelope of the airframe so it sees the deployment charge and is directly affected by it. Would the reading be more accurate if it was isolated from the charge by being in a payload, so that it was only reading outside pressure?

Although that adds a little weight and length to the record attempt, it might prevent the anamonoly from occuring. I don’t know much about this, so if I am off base, forgive me for my ignorance. If this is a true assertion, then that would help ‘sell’ it to the sanctioning bodies.

I’m pretty sure his configurations use a payload bay. At least Barac-it did.

[Anonymous]

Actually this was something I had interest in as well. Were I able to put the altimeters in with the laundry, I’d be able to save considerable space. Over in “lost and found” Adrian had commented that he didn’t see the altimeter in the photo of the found rocket, but wrote “But i think I threaded them onto the shock cord, so maybe they’re deep inside next to the motor? (fingers crossed)”

I’ve always had a sealed ebay, as other altimeter manufacturers continually talk about damage to the unt, corrosiveness of bp, pressure spikes, etc.

Bottom line, if you don’t have to seal this area off, it would greatly modify current building techniques. I’m curious on Adrian’s thoughts here, as MW, Transolve, PF, etc. caution against this.

[elviss_boy]

Give an experienced flyer your rocket, the same motor and your electronics and do it again. Or do it yourself with high supervision. Prove that you can do it, or come close. Science can tell you anything, except when the human factor of skepticism comes along. So prove what you need to, to take out the human factor.

[Author]

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