Altimeter Bay Pics

FredA said:

Sorry Kurt, but stuff happens.

I agree - leave them where they landed, fluff up the chute (at Brothers, dress it over some sage), note the location and report it back to launch control.

Nice idea, but not always possible.

I have had a "BAD" situation at Balls a few years back.
We were one of the last teams leaving the playa and we came across a rocket that was partially deployed (no main, broken fin) and was lying there beeping.

"Noting the location and giving somebody a GPS coordinate" was not an option because nobody was left to give the coordinates to.
We had to take the rocket because it wasn't nice to leave litter on the playa to piss off the BLM plus we were sure somebody wanted it..but it was a freaking twist and tuck.

It took us about a half an hour to find something (we were packed) that could fish out the wire and get it to shut up.
There was no way it was going to ride 550 miles in the back of the van armed, especially since we had no idea what avionics were involved or what condition it was in.
It DID have a charge that didn't fire.

So don't give me crap that this situation doesn't happen.
The rocket owner was very happy to get his rocket back and vowed to never use twist and tuck again.

A switch on the side marked "ARM" and "SAFE" is SO MUCH MORE FRIENDLY and SAFER.

Over literally hundreds of flights, my team has never had a switch fail or accidently turn off.
I'd rather do what I can to make the rocket flight and recovery as safe as possible for everyone instead of taking building/wiring shortcuts because I'm lazy and want convenience.

Ok - nuff said - I'll shut up now on this topic.

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cerving said:

How about if the altimeter fires the charges one more time right after landing, "just in case"? Unless you come in really hard and it's dead anyway, that's going to be a "safe" situation.

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cerving said:

How about if the altimeter fires the charges one more time right after landing, "just in case"? Unless you come in really hard and it's dead anyway, that's going to be a "safe" situation.

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ksaves2 said:

Unfortunate situation and cause for caution but if you don't have a key for a switch or the right plug for the jack or the right screw driver or ball nut driver you are still out of luck. I agree you are correct it would be easy if there was an accessible
switch and the finder knows what it takes to inactivate it. A keyswitch wouldn't have saved you here unless you had the right key on you. Twist and tuck. Never done that myself.

The crap that I'll give you it didn't blow on you did it? Did the recovery system appear to work? If it came down under drogue only ok there should be some caution here but if the altimeter is beeping out the altitude could be the
ematch failed and if you're not hearing a warning code again the level of fear/concern can be lower. If you can see the charge you can be sure one stays clear of it or if it's a long wire canister take a spade and snap the
wire with the shovel so you got some distance between you and the charge. I wouldn't take a wire cutters to the charge wire unless one has protective gear and it doesn't look that large.
I once disposed of a 1.5gm charge out in the open with a switch and damn that was loud. I bury before I blow no so's not to disrupt the neighbors.

What would you guys had done if it was controlled by a switch you could have access to but didn't have the proper implements to turn it off? Open the ebay?

Ummm, I carry a welders helmet with a clear impact resistant face shield and heavy leather gloves. Am not afraid to wear it especially when I have to lift up a bay in a rocket with a MAD unit in it to shut it off. Kurt

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Steve Shannon said:

All good reasons not to use switches that require a special tool to disarm. You're also presuming that it will be a rocket person who finds the rocket. At our launch site it's just as likely to be a rancher or fisherman. Having a very clearly marked way to safe the rocket may protect them and protect our surrounding landowner relationships.
You can continue coming up with less and less credible reasons to avoid mechanical switches Kurt, but the fact is that one mechanical switch, easily manipulated by an untrained person or even a loop of wire that protrudes outside the e-bay, along with a label explaining what to do and whom to call, would be safer.
I still really like the ease of a mechanical switch in line with the enhanced safety of something like the WiFi switch.

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ksaves2 said:

Steve you are missing the point completely. No switch guarantees safety period. An easily accessible switch that a stranger can easily turn off the electronics without special tools is not likely out there. (Snip)

If you have a mythical switch that a stranger can activate easily I'm all ears and all for it. Placarding ok. Kinda hard on a small rocket. The writing would be too small. If you are contending that a switch makes everything safer you're wrong period.
(Snip)

Kurt

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ksaves2 said:

Cannot argue with that. Nosecone is down in the picture? If it were an L3 project I bet there are folks that would question using a slide switch without seeing your spec sheet on the 50 G switches. Costly?
Nice and I am not being facetious here, Fred would have been ecstatic if your rocket was the one he found and I certainly would have no fear of it. Ah, do we have to make a rule change so everyone has to do it
the way you do for rockets of X size? Kurt

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GrouchoDuke said:

Here's a non-standard avionics bay for ya. I've been meaning to do a post on this setup, but haven't gotten around to it. Here's the short version...

I 3d printed the sled. It fits in the avionics bay in my PML Quicksilver with just enough room at both ends for foam padding that holds it in place. I don't do deployment with this, so I don't have any wires that leave the bay. The avionics set up is for data logging and GPS tracking.

Parts:
Turnigy 2S 300mAh lipo battery
Ready To Fly Quads Micro M8N GPS
Featherweight magnetic switch
FrSky XSR
Seriously Pro F3 Evo quadcopter flight control board running Betaflight or iNav (both work great for GPS tracking & telemetry).
5V beeper
5V voltage regulator

The quadcopter flight control board is the brains. It listens to the GPS and its built-in G-meter, gyros & barometer then packs up all that data & zaps it out to the FrSky XSR. The XSR is an r/c aircraft receiver that also sends out telemetry. I use an FrSky Taranis radio (an r/c controller) to receive the telemetry. It shows me real time GPS coordinates, GPS altitude, speed, baro altitude along with max baro altitude (shown in AGL), max GPS altitude (in MSL) and max speed. With a 7dB patch antenna on the Taranis, it gets just under 3 miles of range when the rocket's about 6 feet off the ground. The Evo flight controller also has a built-in micro SD card that records the entire flight at up to 1000Hz. The Taranis also records the telemetry, but it's much slower at about 1Hz.

View attachment 311242 View attachment 311243 View attachment 311244

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GrouchoDuke said:

Here's a non-standard avionics bay for ya. I've been meaning to do a post on this setup, but haven't gotten around to it. Here's the short version...

I 3d printed the sled. It fits in the avionics bay in my PML Quicksilver with just enough room at both ends for foam padding that holds it in place. I don't do deployment with this, so I don't have any wires that leave the bay. The avionics set up is for data logging and GPS tracking.

Parts:
Turnigy 2S 300mAh lipo battery
Ready To Fly Quads Micro M8N GPS
Featherweight magnetic switch
FrSky XSR
Seriously Pro F3 Evo quadcopter flight control board running Betaflight or iNav (both work great for GPS tracking & telemetry).
5V beeper
5V voltage regulator

The quadcopter flight control board is the brains. It listens to the GPS and its built-in G-meter, gyros & barometer then packs up all that data & zaps it out to the FrSky XSR. The XSR is an r/c aircraft receiver that also sends out telemetry. I use an FrSky Taranis radio (an r/c controller) to receive the telemetry. It shows me real time GPS coordinates, GPS altitude, speed, baro altitude along with max baro altitude (shown in AGL), max GPS altitude (in MSL) and max speed. With a 7dB patch antenna on the Taranis, it gets just under 3 miles of range when the rocket's about 6 feet off the ground. The Evo flight controller also has a built-in micro SD card that records the entire flight at up to 1000Hz. The Taranis also records the telemetry, but it's much slower at about 1Hz.

View attachment 311242 View attachment 311243 View attachment 311244

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Steve Shannon said:

Here's what I do. This is a 4 inch rocket. I've done the same as small as 2.1 inch and as large as 7.5 inch.
Thrust keeps the switches in the on position. The only gee forces that can switch off the switches would be to strike something such as the ground. The switches are rated for 50 gees in six degrees of freedom.
I think you'll agree the text is large enough, but it could use a warning.

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JimJarvis50 said:

Aren't you a bit worried about the harness turning off the switch?

Jim

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Steve Shannon said:

Well, although it's never been a problem before, now I will be! [emoji15]

Actually, after seeing Fred's pictures, I decided I would see if I could move the switches inside the switchband with countersunk flat head screws on the outside so that the handles on the slide switches sit low or even slightly below the surface.

Thanks, Jim! I can see how that could happen, even though it never has yet.


Steve Shannon

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BDB said:

I agree, this is very cool. Can you tell those of us who aren't RC guys us a little more about where you got this and if it was difficult to adapt for rocketry.

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ttabbal said:

I usually buy my FrSky gear from Aloft Hobbies.

If you are interested in R/C, it's a very powerful radio for a fraction of the price of the big names. Really great stuff. Price is competitive with some brands of trackers too. It uses the 2.4Ghz unlicensed band, so no need for ham licenses, and is very resistant to interference. You can also use it to fly some of burkefj's really cool boost gliders. Just grab one of the little 4-channel receivers.

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Steve Shannon said:

Is the gps limited for vertical velocity? Can the output be linked to a mapping application on a tablet? What diameter is that sled?

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GrouchoDuke said:

Thanks!! It was a really fun project to do. It's kinda fun to have a different setup than everyone else I meet.

I got sick today, so excuse me if this is a jumbled mess...

It's really hard for me to say. I've been doing work with r/c flight control boards for about 4 years, been doing r/c stuff for over 30, and working with real aircraft flight control computers on & off for about 25 years. I've been writing some code & doing lots of flight testing for various flight controllers, so I'm pretty familiar with it all. That said, my guess is just about anyone who can wire up standard rocket avionics could put a similar setup together without too much trouble. There are some different aspects to it though like setting up the GPS through an FTDI & U-blox's u-center and loading firmware & changing configurations on the flight control boards. There are probably YouTube videos or blog posts out there that cover every part of it. For rocket specific stuff like my setup here, I really should do a big how-to post. If other people are interested in putting this kind of thing together, that'd save people a bunch of time.

It's not designed for rockets, but it seems to work really well. The biggest gotcha with it is that if you don't have a controller radio with telemetry (like the Taranis), then the cost of getting all the parts starts to get right up there with the dedicated rocket avionics. To do any chute firing, you'd have to modify the flight control code and build a circuit to handing the power going to the charges. The accelerometers in most r/c flight control boards are usually set for a max range of 8G's. Many can be toggled to 16, but getting above that is probably not something you'll find without going to dedicated rocket avionics. You could still back out acceleration from the baro data though.

For me, I just wanted to do motor ejection with this Quicksilver. The biggest I'll probably ever put in it is a small J (like a J270W) and that'll take it up in the 6500' range. With a max of a 20mph wind the max the rocket should ever drift is about 1.5 miles...so that's the bounds of what I wanted tracking for.

Honestly, if I had known about the Eggtimer TRS or Eggfinder when I started my Quicksilver build (for my L1 cert), I might have just skipped the r/c stuff and gone with one of those. I have an Eggfinder sitting on my bench that I need to build. I'm looking forward to trying it out. It's awesome they have a GPS tracking solution for about $100. I'm also interested in trying the Altus Metrum tracking products. I have an EasyMini (no tracking), but a TeleMini (v2 please?) and/or TeleMetrum might be in my future too.

Anyway, the process is roughly:
- buy parts
- load & configure flight control software
- tweak GPS settings (or set the flight control software to manage it through the U-blox protocol)
- solder all the serial port wires to the right places
- solder power/switches/etc how you want them
- configure r/c transmitter (ground station) for telemetry screens
- mount on the sled
- test & fly

Yeah, Aloft is great for FrSky stuff. I've also bought stuff off Amazon. For each of the other parts, Google can find them quickly. I'm pretty sure it was a different online store for each part though. 2.4 is a really nice band for these moderate range applications.

It's a U-blox M8N (or possibly a clone of one), so it's velocity limits depend on how you have it set up. The U-blox GPSs have different dynamic models (from pedestrian to several airborne modes) that all have different limits. The pedestrian setting seems to be really good at getting quick locks on the ground and when under chute. Some of the other modes do better at keeping the track flowing under high speed flight, but they seem to take more time to lock on initially. I wish U-blox had a "rocket" dynamic model we could use.

The Quicksilver main body tube is 54mm inside diameter. My 3d printed sled fits in that and is about 6.5" long. I could definitely make it smaller, but that's sized to fill my av-bay. There are also much smaller flight control computers that could cut down on the width requirements.

There are sooooo many different flight control computers that you really have to just figure out the features you want & find a board that has them. The Betaflight F3 flight controller looks like it might be a good one. It has an onboard voltage regulator & SD card slot. It's SD card slot is a shortened one though, so I'm not sure how it'd do in higher G rockets.

I don't currently have my ground station Taranis radio outputting to anything. I just input the coordinates into iArrow on my iPhone or scroll around in my own app, GPS Location, to see where the rocket landed. I believe it's possible to connect a little $10 Bluetooth module to the Taranis then have it send data to a computer or other device. I've been thinking about setting that up and programming a quick "Kate"-type application. I keep building more rockets instead though.

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JimJarvis50 said:

Years ago, I had a rocket with the PML CPR system, and it had an external switch. I thought it was a potential problem, so I put the switch on the altimeter board (starting a trend I guess). Since that time, I've seen many cases in my flights where the harness obviously strafed the body tube or fins.

Jim

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FredA said:

I mount my slide switches horizontally.
No need for super-strength switches....certainly not 50G rated.

We have 100's of flights using the Switchcraft 50212LX 4PDT's at two per rocket....NEVER and issue.
You do need to glue down the metal tabs where they bend around the phenolic contact board and they are bullet-proof for our application.

Usually we cut a 1/4" x 1/2" slot in the switch-band and glue them to the inside of the EBay and sand off the handles so it does not protrude proud of the outside of the body.

Super simple. Very robust.
Mouser sells them for ~$6 in low quantity - I bought a few hundred at surplus for 25 cents each.
Have them in every rocket out team flies ... a few dozen of rockets, a few hundred flights.

A little label on the outside and the most you have to worry about is the label burning off and the handle melting when going over Mach2.....

Yes, I'm sorry - I said I was done with this thread, but couldn't resist since Kurt keeps invoking my name.
This is a picture from my L3 from 13 years or so ago...it that happens to sit in my den so it was handy to pose for the shot.
Yes, it's a huge switch band .... I don't build them that big anymore....

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GrouchoDuke said:

Thanks!! It was a really fun project to do. It's kinda fun to have a different setup than everyone else I meet.

I got sick today, so excuse me if this is a jumbled mess...

It's really hard for me to say. I've been doing work with r/c flight control boards for about 4 years, been doing r/c stuff for over 30, and working with real aircraft flight control computers on & off for about 25 years. I've been writing some code & doing lots of flight testing for various flight controllers, so I'm pretty familiar with it all. That said, my guess is just about anyone who can wire up standard rocket avionics could put a similar setup together without too much trouble. There are some different aspects to it though like setting up the GPS through an FTDI & U-blox's u-center and loading firmware & changing configurations on the flight control boards. There are probably YouTube videos or blog posts out there that cover every part of it. For rocket specific stuff like my setup here, I really should do a big how-to post. If other people are interested in putting this kind of thing together, that'd save people a bunch of time.

It's not designed for rockets, but it seems to work really well. The biggest gotcha with it is that if you don't have a controller radio with telemetry (like the Taranis), then the cost of getting all the parts starts to get right up there with the dedicated rocket avionics. To do any chute firing, you'd have to modify the flight control code and build a circuit to handing the power going to the charges. The accelerometers in most r/c flight control boards are usually set for a max range of 8G's. Many can be toggled to 16, but getting above that is probably not something you'll find without going to dedicated rocket avionics. You could still back out acceleration from the baro data though.

For me, I just wanted to do motor ejection with this Quicksilver. The biggest I'll probably ever put in it is a small J (like a J270W) and that'll take it up in the 6500' range. With a max of a 20mph wind the max the rocket should ever drift is about 1.5 miles...so that's the bounds of what I wanted tracking for.

Honestly, if I had known about the Eggtimer TRS or Eggfinder when I started my Quicksilver build (for my L1 cert), I might have just skipped the r/c stuff and gone with one of those. I have an Eggfinder sitting on my bench that I need to build. I'm looking forward to trying it out. It's awesome they have a GPS tracking solution for about $100. I'm also interested in trying the Altus Metrum tracking products. I have an EasyMini (no tracking), but a TeleMini (v2 please?) and/or TeleMetrum might be in my future too.

Anyway, the process is roughly:
- buy parts
- load & configure flight control software
- tweak GPS settings (or set the flight control software to manage it through the U-blox protocol)
- solder all the serial port wires to the right places
- solder power/switches/etc how you want them
- configure r/c transmitter (ground station) for telemetry screens
- mount on the sled
- test & fly

Yeah, Aloft is great for FrSky stuff. I've also bought stuff off Amazon. For each of the other parts, Google can find them quickly. I'm pretty sure it was a different online store for each part though. 2.4 is a really nice band for these moderate range applications.

It's a U-blox M8N (or possibly a clone of one), so it's velocity limits depend on how you have it set up. The U-blox GPSs have different dynamic models (from pedestrian to several airborne modes) that all have different limits. The pedestrian setting seems to be really good at getting quick locks on the ground and when under chute. Some of the other modes do better at keeping the track flowing under high speed flight, but they seem to take more time to lock on initially. I wish U-blox had a "rocket" dynamic model we could use.

The Quicksilver main body tube is 54mm inside diameter. My 3d printed sled fits in that and is about 6.5" long. I could definitely make it smaller, but that's sized to fill my av-bay. There are also much smaller flight control computers that could cut down on the width requirements.

There are sooooo many different flight control computers that you really have to just figure out the features you want & find a board that has them. The Betaflight F3 flight controller looks like it might be a good one. It has an onboard voltage regulator & SD card slot. It's SD card slot is a shortened one though, so I'm not sure how it'd do in higher G rockets.

I don't currently have my ground station Taranis radio outputting to anything. I just input the coordinates into iArrow on my iPhone or scroll around in my own app, GPS Location, to see where the rocket landed. I believe it's possible to connect a little $10 Bluetooth module to the Taranis then have it send data to a computer or other device. I've been thinking about setting that up and programming a quick "Kate"-type application. I keep building more rockets instead though.

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Steve Shannon said:

About 15 years ago, after what I thought was an Aerotech bonus delay, I converted all my smaller rockets 2.1 inch and up to CPR systems so I have these switches sticking out of a few rockets. By now I've had some wear and tear so I'm down to one left, I think a BBX, with the CPR. I probably won't move its switch inside; I don't think there's any way. The only strap that would matter would be to the drogue. If it caught on the switch then the main would not eject.
So, I don't think there's a huge risk there. That rocket is near retirement age anyway.
But it should be easy to move the switches on this rocket and future rockets into a guarded position where I can still turn them on with my fingers, but the strap cannot snag them.
Thanks for the information.

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