Single Shot Sweepstakes 2006

[Bruce R. Schaefer]

… and the wind is calm–at best, dead. Honestly, I’m probably going to just sim, build and launch. While it goes against my engineering experience, there’s something I have to do to the rocket, other than wax, that I only want to do once.

[Chris LaPanse]

I personally will not be test-flying mine. It would be too difficult to find, and I want to maximize my chances of finding it. If I loose it, I want to loose it on the qualifying flight, not a test flight.

[Bruce R. Schaefer]

I know what you’re saying. But, Chris, if you lose it, you don’t qualify anyway. It has to be turned in by the end of the day’s flight time. It’s still gone. I have two versions: one, apogee deployment (less weight), and two, dual deployment (more weight). With the DD, the chances of losing it are pretty slim. Might be better to have a recovered rocket with less altitude, than one that was lost with a record-setting altitude. With apogee, depends on the weather and seeing conditions… and luck. After all, we only have to beat each other. I still don’t know, but I want my options open. I DO know this, with Warren’s 15 and your 14.8 second delay, providing it’s for apogee, you’re both near 7,000 feet, if not over it. 6,500 feet is more than achievable, and most should do that. ‘Nuff said. 🙂

[Chris LaPanse]

I know, but I would rather not qualify by loosing it while trying than by loosing it on a test flight. I agree about the DD issue – still debating about whether to go dual or not.

[Anonymous]

Just curious if you guys are using the file for the NEW Aerotech G80 or the older motor? This contest stipulates that the new G80 must be used. It has 20% fewer NS than the old G80. If anyone gets 7K on the new G80, then they need to have their altimeter checked (I’m serious).

6K would be an awesome, incredible shot. 7K? Not gonna happen with the new load. Not with a properly calibrated altimeter.

[Bruce R. Schaefer]

Agreed. It’s my understanding that all are using the correct AT G80 version in their sims. The key is a low Cd, and unless you have a wind tunnel, that’s only a SWAG using age-old techniques.

[Bruce R. Schaefer]

Just curious if you guys are using the file for the NEW Aerotech G80 or the older motor? This contest stipulates that the new G80 must be used. It has 20% fewer NS than the old G80.

Okay, now that I’ve had time to verify what I said earlier, and all trash talking aside, I checked my software (SpaceCAD–which has been very accurate in the past), and it has two AT G80’s: one G80 and a G80T. Looking into the engine data files, the G80 has 119 N/s, and the G80T has 99 N/s. So, technically the G80T is the one to use. However, when I use the G80 (the more powerful motor, by 16.6%), my rocket doesn’t go near as high as the G80T. Since the contest is underway, I can’t–or won’t–go into details of my respective settings in the software because that can give some of my gameplan away. I can get a delay from 12-17 sec., and altitudes ranging from 4800′ to over 7100′. Neither is correct. So, my altitude will be in that range, as will everyone else’s. Boy, I gave nothing away in this e-mail, did I? 😆 You know that saying “a month of Sundays”? Well, the rocket is built… so now it’s layers of various paint and covering types and “a month of sanding.” I really hate this part, but it makes the difference between ensuring all the trade-offs like fin shape, fin tip, optimum weight (lightest rocket never wins, by the way… can’t; laws of physics won’t allow that–think about the phases of flight, inertia, momentum, etc. But everyone knows that, right?), component placement, etc. work. We all know a bad paint job can negate all the neat techniques. Oh well, back to sanding while the sun’s still out…

[Warren B. MusselmanModerator]

Sanding and painting is ALWAYS the reason my projects are late or don’t fly when I intend.

Warren

[denverdoc]

Not sure to what to attribute the diffs, my Rocksims vary considerably depending on small items, but I get 7500 consistently. I believe at least 80% of that ( based on past experience) is reasonable expectation for even less than optimal flight path.
JS

[Bruce R. Schaefer]

Hey, I remember when I calculated all this by hand, way back in the mid to late 60’s. And it was a helluva lot closer. 😆 The really good thing about this is not all the calculations and sanding, it’s the flight… and the camaraderie to help you find and pick up the pieces after you’ve searched the prairie for hours for the results of all your hard work. All the best laid plans of mice and men, right? I just love this kind of competition. NAR traditionally is better at it only because we had to optimize low power, while TRA could just power their way up. The skills in this club, either NAR or TRA, are just tremendous. The best. Even with Lucerne Lake just an hour or two away while I lived in So. Ca., this is the best club I’ve ever been in. And I’ve waited a long, long time. 😆

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