High Altitude Balloon Project

#81

Well, I forgot about last week. Oops.

For some reason the He connector still has not arrived. I will look into this. In the meantime, I will probably take a look at the regulator at DMS to see how hard it’d be to pull off the part I need.

Should we hold the meeting tomorrow or next week? Next week gets back to original bi-weekly schedule, but tomorrow minimizes the risk to the project’s momentum.

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#82

We’ll do the meeting next week. The part came in and it was the wrong part, so I’ve got some … choice words for this company’s part pictures. I’ll probably be releasing my redtailed hawk today instead.

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#83

Next week works for me! I’ll try and prep the payload container before then.

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#84

Latest issue of Make (arrived in mail yesterday) has an interesting article on a father and daughter high altitude balloon project. Discussed a lot of same issues on this thread.

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#85

Alright. Meeting tonight at 7pm. I’m going to try to call FAA today.

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#86

If anyone arrives, I’ll be over in Electronics resoldering the FET.

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#87

Hey guys, please attend one of the 2 Aerospace/RC Committee meetings I have scheduled on Oct. 7 or Oct. 14 to discuss the High Altitude Balloon Project.

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#88

Alright, meeting tonight at 7pm again. I’m planning on grabbing things for the balloon filler / tank attachment thing. Once that’s done, the only things left for launch 1 are the internals (Pixhawk and APRS) and the actual mechanics of the NiChrome / cutaway between the balloon and the box.

Once it’s all together, I figure we’ll be taking a Saturday with Nick’s quad to get used to all of the radio stuff and to make sure everything works well together.

We should probably make any necessary flight checklists soon.

If Nick doesn’t show tonight, I’ll be getting my own Pixhawk to work with.

I called FAA a while back and got transferred to a not-present Mr. McAllister, so I called again today and managed to get in touch. Apparently he doesn’t know about HAB operation; I may have to call someone in DC to discuss. But while I was looking for more info today, I found 14 CFR 101 (took a while …), so there’s that.

If I’m reading 101.1 correctly … there’s a potential we could not be regulated at all.

(a) This part prescribes rules governing the operation in the United States, of the following:

(4) Except as provided for in §101.7, any unmanned free balloon that—

(i) Carries a payload package that weighs more than four pounds and has a weight/size ratio of more than three ounces per square inch on any surface of the package, determined by dividing the total weight in ounces of the payload package by the area in square inches of its smallest surface;

(ii) Carries a payload package that weighs more than six pounds;

(iii) Carries a payload, of two or more packages, that weighs more than 12 pounds; or

(iv) Uses a rope or other device for suspension of the payload that requires an impact force of more than 50 pounds to separate the suspended payload from the balloon.

I’m a bit confused at what the physical interpretation of “impact force” is, since an impact would be an impulse rather than a force. Kind of like asking for a “position acceleration”. Wtf.

So far I think this means if we can design it to fail all of (4), we are unregulated. I think that means we can do whatever we want, but until the FAA actually tells me that or I read and understand all of FAR I’m going to be real careful. I’m pretty sure we can’t just do literally whatever.

How many people would be interested in participating in a weekend launch?

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#89

Chesley, I’m planning to be there tonight.

My ToDo list:

  • Build new Foam payload housing, figure out electronics placement and integration
  • Configure Pixhawk for telemetry recording and activation of Nichrome relay upon specified altitude
  • Configur APRS TX and troubleshoot Baofeng interface cables for APRS recieve
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#90

Parts are on a table in the common room. I’m running to Home Depot to get PVC stuffs and maybe a hose; would have grabbed it earlier but realized I really needed the parts on me, so I came down to the makerspace first.

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#91

Don’t forget about our official “Committee Chair Discussion Meeting” tomorrow.

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#92

Here’s another great video from a successful HAB Glider launch project: https://www.youtube.com/watch?v=qC6Tet-Jvew

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#93

Alright. Time again for another meeting this evening at 7pm.

Phase 1 TODO:

  • Finish Pixhawk programming (interface to cutter, interface to APRS)
  • Finish APRS system
  • Figure out how we tie the payload to the balloon
  • File paperwork / get clearances from FAA as required
  • Assembled electronics functionality testing
  • Quadcopter drop testing, with as much system coverage as feasible
  • Pre-launch preparation (checklist generation, any “dress rehearsals”, final launch site selection, helium rental / purchase, etc.)
  • Launch

I will work on the payload tie, and if I get that done I will start studying for a radio license again so I can do the APRS stuff. I want Extra in the first shot, y’all. I will also try to remember to call FTW FAA today.

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#94

I’ll be up there tonight doing some plane work, I can help test the payload tie if needed. I’ll bring my quadcopter and we can test dropping stuff from it :slight_smile:

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#95

I won’t be in town next Tuesday. However, I can still set something up if others want to come and work; the to-do is mostly the same.

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#96

Back in town.

Nick, how goes the electronics?

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#97

Did you get the TTRS adapter to work for you? Did mine a few months back and it doesn’t work… Think there might be too much static in the line and it just trips the VOX.

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#98

Meeting tonight at 7pm.

I called ZFW, who is apparently the correct FAA entity (i.e., not North Texas FSDO). I was told that:

  • We should call 1-2 weeks before launch, gave me a guy and a number to call
  • They split the area into sectors, and we need to call whoever runs the sector; the guy I was given apparently is good for NE of Dallas for that prairie area we’ve looked at, but if we want a different launch site we might need to call someone else
  • We are probably unregulated, but that doesn’t have to stop us from informing them
  • We probably don’t have to add a radar reflector, but he didn’t seem as sure about this
  • What we probably will do is call ZFW 30 minutes-ish before launch to inform them and … I think he said we call to update them on its altitude as well. So I think we would call at milestones like 20k ft, 30k ft, etc.
  • We don’t have any paperwork to file, or anything like that

For the attachment mechanism, I think last time we discussed going with something like 80lb fishing line instead of trying to do some elaborate paracord thing held together with lighter fishing line.

I believe we also lost the cutter FET, but that’s not a huge deal since we have about a dozen others that would only need resoldering of the wires. I also lost the NiChrome, which would be a bigger deal, except it’s like 3 bucks. This leaves shifting the Pixhawk output to a 5v on-off output via some mechanism. I haven’t looked into it a lot yet, mostly because I don’t know what Pixhawk outputs I can make work, and having to shift it with a custom something is a lot of work for something that should be off-the-shelf somewhere. (That being said, it’s the second time the on-off signal via PWM problem has come up for me, so maybe it’s worth doing some “fast” board with a PIC10 or somesuch.)

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#99

Tanner carries NiChrome wire cut to length, I noticed it there last week. Also, I could build a circuit if needed to convert the PWM output from the pixhawk to a simple on/off switch. I did exactly that for the landing light control on my RC plane. I used an ATTiny85 chip, and I still have some spare ones laying around.

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#100

If you’ve already got the circuit worked out, I’ll go with that. Main reason I wanted something off-the-shelf was because I didn’t want to spend a bunch of hours debugging a PIC10.

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