Well first you'll have to beat me and John Wilke - you can damn well bet he'll be defending his standing records and since I've got probably the last few F32's and G55's in Colorado, you can bet I'll be going after those records in the next couple months. I hold the current club E record and since I know you beat it pretty handily, I'm going to have to build a new E record bird just to make sure I keep it. However, I must say that this is a kick in the ass to have some more folks interested in setting altitude records. (More on that later.)

Second, removing the ejection charge in a single use motor is not considered modification - you can do that with impunity. Just don't try to remove or modify the delay charge, nozzle or casing. I highly recommend you plug the hole in the forward closure with epoxy after you remove the ejection charge. Personally I usually epoxy in a small screw-eye and use it to retain the booster section of the bird.

Finally, I should say that NCR won't accept your altimeter as an acceptable altimeter for altitude records until Tripoli approves the production version. Any record attempts will have to have an approved altimeter on-board for the altitude to be accepted for a record attempt if flown prior to Tripoli's approval. Also, your altimeter will have to be the identical production version to that approved by Tripoli and not a test or development item.

By the way, slick little altimeter you have there. Love all the data it provides and if it reads out in feet and/or meters AGL via beeper and LED AND provides dual deployment, you've got a real winner - the download capability is pure gravy. If it doesn't provide deployment, you'll probably not sell too many of them except to the low power guys. On the other hand, given the sophistication of it, if you could tack on timer capabilities, multiple high-power outputs, pull-pin, and a GPS interface, you could compete favorably with the ARTS or RDAS. Very sweet design.

Warren

Just a short f/u to Warren's post--Nar rules/records prohibit modification of motors in any way, including removal of BP in SU motors. TRA does not--which is one reason for the wide disparity in altitude records. In other words, w/o removing the EC, none of the records for SU would be close to exixting records. So dump it, but good idea to epoxy plug as warren suggests.

For the sss, i drilled holes at the forward end of the case that tubing goes thru, and is epoxied n2 place, then filed flush with the OD. Makes a good hold for shock cord.

I'm genuinely delighted to hear about the renewed enthusiasm with altitude.

Oddly enough, I have not flown an A, B, C, or D motor in perhaps 15 years. On top of that, I have never once flown an E. Given my geographical constraints, mayhaps I will revisit that whole paradigm (hey, that is a GREAT rocket name...) It is a *totally* different type of construction. I have no idea of how to build something light. I'm typically more worried about how to keep the fins on at mach 2.

J

Let me say up front, before I'm tempted to talk any trash, that I really respect what you guys have done, both in the area of records (John's G record bird is (was? :() a thing of beauty) and more importantly in providing a fun and fair playing ground. Whatever else I accomplish in the record area, I hope to contribute to the friendly and fun spirit of competition we have going here.

Well first you'll have to beat me and John Wilke - you can damn well bet he'll be defending his standing records and since I've got probably the last few F32's and G55's in Colorado, you can bet I'll be going after those records in the next couple months.

You and John can duke it out for the G record; I'm just going to focus on the subsonic birds for now, and settle for the A through F records. 😉

The Apogee medalist motors --well, the E6 and the F10, anyway-- have versions with long enough delays to do some serious bar-raising without any mods. My question about the ejection charges was motivated more by trying to avoid blowing apart my shock cord like I did on Saturday.

I'm tempted to become a NAR member so I can try to get on the record board over there, too. I think I'll probably design with a full-strength, full-length shock cord, even if it takes away a few hundred feet of margin, so I don't have to monkey with the deployment charge.

timer capabilities, multiple high-power outputs, pull-pin, and a GPS interface, you could compete favorably with the ARTS or RDAS. Very sweet design.

You don't ask for much, do you?
So far, developing the Parrot for production has taken all of my available time for the last 4 or so months, and put a serious dent in my wallet. So I'm going to focus on getting those built, calibrated, certified, and then out the door before I spend more time on the next version. But just so you know, I have a mostly-bare prototype board sitting on the bench for an alt called the Peregrine that will have three high-current outputs (compatible with Estes igniters and copperheads, if my calculations are right). The trouble is that the code in the Parrot maxes out the code space on the sweet little microcontroller I'm using for the Parrot, so I'll either have to eliminate some features of the Parrot in order to squeeze in the deployment logic, or....I have some other concepts.

I have no idea how many Parrots I sell, but I hope it's at least 40, because that's how many sets of parts I ordered from Digikey last night. Apogee probably sells a fair number of the non-deployment Perfectflite altimeters from their site, if I were to guess, but who knows.

I'm working on handing off the production panels and the parts to a professional assembly house on Friday. I should have some production alts to put through whatever certification wringer Tom Rouse has in mind in a couple of weeks, if all goes well. I'm definitely due for an update from Tom on what I'm going to need to do next for certification.

Excellent Adrian. It's a really sweet product as it stands. What's flight weight? How much do you expect to charge for them?

Warren

Oddly enough, I have not flown an A, B, C, or D motor in perhaps 15 years. On top of that, I have never once flown an E. Given my geographical constraints, mayhaps I will revisit that whole paradigm (hey, that is a GREAT rocket name...) It is a *totally* different type of construction. I have no idea of how to build something light. I'm typically more worried about how to keep the fins on at mach 2.

The nice thing about building light is that the rocket is 90% built as soon as you push away from the computer, which is the only reason a newbie like myself has a shot. I'm sure I'll shred plenty of fins before I figure out a better way to set an H record

What's flight weight? How much do you expect to charge for them?

The last time I weighed one with an accurate scale, it was 7.6 grams, but that was my first prototype. Since then, I've added some components, including a 2-56 screw switch, but the board is slightly shorter, so it should stay around 8 grams including the battery, which is what an A23 battery weighs. I've been meaning to get a good little scale for months now; I know they're cheap these days.

For the first run I'm charging $110, which will cover the cost of parts and surface mount assembly, plus my time for the remaining assembly and calibration. In a few days they will be available for pre-order on featherweightaltimeters.com

An F motor bird, done 29mm for the Apogee F10, doesn't stand a chance against a 24mm motor. The additional diameter and concomitant increase in drag overcomes the longer burn and will make it quite difficult to fly much over 5K regardless of weight. The standing F record is going to be a tough one to beat since the motors necessary to beat it just aren't made anymore. Given that the only remaining certified motors capable of it - the F32 and F72 haven't been made since before the Aerotech fire and go out of certification at the end of December, I'll be very surprised. I still have 2 F32's, one of which I promised to John in the event he needs to defend his record. (Of course I'm going to use the other one to take his record...)

An E motor bird for the Apogee E6 optimizes weight-wise down around 25 grams and I'll be damned if I can figure out how to built a rocket that will survive AND carry an altimeter at that weight. On the other hand, I have an E bird that sims almost 2K higher than the record bird I flew which was not weight optimized nor was it flown on the motor it was designed for. I threw that bird together in an evening, painted it and then flew it the following week with the only E motor that was sitting in my flight box. It was a test for an F version of the same design. The E record is low-hanging fruit for sure.

For sub-E records, there is a lot of low hanging fruit out there. I've actually never seen anyone at NCR build a bird specifically optimized to take those records and none of the currently available commercial altimeters are light enough to fly without significantly impacting the altitude reached. All records E and down weight-optimize below the weight possible to build them. If a bird for the E6 optimizes around 25 grams, a D or C bird is going to be concommitantly lower and unless you get into some esoteric building techniques like a single layer carbon fiber tube, I doubt you can optimize for altitude by weight. On the other hand, there's a lot of low-hanging fruit down there - especially the A and B records although all 4 could probably be readily bumped up higher.

On the higher power motors, there isn't so much low hanging fruit. Although Chris did very well with his I600 shot, that's far from the optimal I motor for a record and again, unfortunately, the ideal motors are out of production. The J world record is probably impossible to beat as is the K and L. Again a matter of the ideal motors no longer being made.

By the way Adrian, put me down for one of those altimeters when you've got one that will do at least Apogee deployment. Without electronic deployment, you really can't optimize for altitude. My E, F and G birds all come in around 14-17 seconds optimal delay.

Warren

Warren,

all i know is what Rocksim tells me. I assumed for a long time that the extra area (approx 30/25^2=36/25, or roughly 45percent more would make such a venture out of the question. Then when the motors were certified for contest use, I took a second look.

Payback for the frontal area sacrifice comes in avoiding transsoic and supersonic velocities where the Cd can easily double from the nadir, usu at around 600-700 fps. A long burning 24mm F would obviously be the ideal.
J

The J impulse TRA record is just nuts. I passed the old record a year ago, but not by 2%. By the time I had another crack at it, the record went from ~16,700' to almost 20,000'. On a perfect day with a perfect shot at Hartsel (if they had a waiver that high) with an optimized rocket with apogee deploy (to keep length down) I can't imagine doing 20K. When I cracked 17K on a J, I told myself I'd retire that rocket. I don't think an airframe has an unlimited number of 70G boosts.

I've seen a lot of guys take their swing at the plate for the F record, and it is harder than it looks. I'd love to see a fellow NCR member nab the TRA F record.

Warren is right -- many of the other records are out of reach due to motor restraints. For example, there is no longer a full K long-burn SU motor. The new K250 is not nearly a full K. Many of those records will stay intact unless new motors become certified.

JW

Yea, there's a minor beef I have and one of the reasons some of the staged records strike me as more inviting--IMHO any record that flew on a now legacy motor should be retired at the time the motor becomes unavailable. Course, there can still be an all time list. Otherwise like the F, the I and the K records they just sit there collecting dust. I believe the Ellis su L330 may soon become extinct as well. (Course I have some 24mm F's and two G55's I'm hanging on to til then)

As to the 90 percent point, (at least with F and above) I would have to opine that would be sometime during descent after the recovery device has deployed and someone has seen it recently or they have a radio fix. The build is easy, the ascent is even easy,its finding the darn things!

Yeah, without a tracker, getting it to a record-breaking apogee would only be 10% of the battle. I'm pretty happy with my new BigRedBee. It took me (evenually) to my separated E nosecone which was invisible until I was about 10 feet away from it. I've been lobbying the guy who makes them (Greg Clark, if I remember correctly) to come up with a narrower version. There's only so far you can go by trimming the board edges with a belt sander!

Also, isn't the missleworks guy (sorry, I don't remember his name) working on a nice small tracker? Perhaps 18mm compatible? He offered for Chris and me to fly it on Chris's cirrus dart flight, but I had too much tunnel vision trying to get ready at the time to take him up on it. I have stuffed my bigredbee into an 18mm tube (not the nosecone) and even with all the belt sanding it ovalizes the hell out of the tube. So I'm unsure about the best tracking method for C and under. An oversized streamer might be lighter and better than the BigRedBee for those alititudes. For the 18mm D, I just can't imagine trying to keep a visual fix on it without a giganto-enormous streamer so I'll find some way to cram the BRB in.

An F motor bird, done 29mm for the Apogee F10, doesn't stand a chance against a 24mm motor. The additional diameter and concomitant increase in drag overcomes the longer burn and will make it quite difficult to fly much over 5K regardless of weight.

I'm so tempted to help you see the light on this one, but mabye I'll just do it by demonstration 🙂

Adrian,

Not sure who that might have been. With your electronic talents, simple matter of finding a schematic on line and making it even smaller if not small enuf. I assume you have a HAM lisence. . I'm happy that the BRB tracker fits in a 29 NC and the GPS in a 38. Greg flies some small stuff so he might be amenable to a narrow version. But last I looked theres some really dinky stuff on the net.

I have a 433mhz transmitter module that will fit in a 13mm tube. The problem then becomes the battery and keying module necessary to make the beeps. It's not GPS, but it will provide RDF type tracking.

Warren