Altimiter swapping

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viciouspeanut

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Hey all,

I'm about to have two dual deploy rockets and will only have one altimeter for a bit so my question is how many of you swap unit from rocket to rocket, or do you have dedicated units that stay with one kit? I imagine that is more ideal and will probably move that way, but for now I would like to swap.
 
I try for dedicated but still have fewer altimeters than rockets that need them so its necessary to swap one or two between rockets (my RRC3 typically does this duty).
 
I have dedicated, but only because I like to fully prep at home and bring rockets ready to fly (except turning on GPS, putting in shear pins).
 
Gosh, I probably have 20 rockets that can be dual deploy, I have 3 altimeters (all the same model) - so its safe to say I swap. I try and make all my altimeter sleds interchangeable and prep them at home.
 
With the 3d printed sleds, it's real easy to make your AV bays modular. Altimeters, batteries, and switches stay on the sled, all you have to do is keep the bolt spacing the same.
You can also do this with home made sleds, but just sayin...
 
I think if one plans well they don't have to swap. Learn to solder and do a Quark for all the simple rockets or buy an Adept 22. What Adrian states is very valid but........... Kind of a pain to do out in the field so's to fly the second rocket.
Fly the lower flying rockets first and the higher ones that require tracking later unless you have the luxury of a dedicated recovery team. Prep more than 2 or three high fliers and you try to fly them first before your lower fliers, you'll go home
with prepped rockets. Ok, ok. If you recover via motorized vehicle will cut down on the recovery time but if you have to walk it, it takes more time. Kurt
 
I have 2 altimeters. Most of the the time I fly both of them for redundancy. If you design your altimeter bays so that it's easy to swap them out it's not a problem. I use 4-40 screws and PEM nuts on all of my trays so that I just need one tool to install or remove the altimeters. I usually leave the batteries and switches in the altimeter bays so all I have to do it move the altimeters and hook them up. Keep your wiring simple and it's not too hard.
 
I have one altimeter sled that will fit inside a 3" diameter bay. I slide it out and put adapters on the ends so it will fit any of my larger diameter bays. The avionics sled has 2xEggtimers and 1xEggfinder. The Wifi arming makes it easy to swap the sled since I don't have to worry about physical switch connections. I re-use it for a few reasons:

1. It's cheaper
2. It's a tried and true system that's never failed me, so I trust it now
3. I put a lot of time and effort into building those electronics, so I want to get maximum usage
 
Thanks for all the input guys, appreciate it. Both rockets are 4" so I should be able to use the same sled for a while I guess (I can use RC fuel line to cushion sled for different length bays). Then I'll grab an already built Quark or something (terrible at soldering) and use that in one of them.
 
I have more altimeters than I can fly in one day. I prep the bays at home. And another Quark to build.

Even still, I try to avoid screwing/unscrewing the terminals and mounting/unmounting the board too much. The more I fool with it, the more concerned I get about breaking something.
I started on a modular quick switch system. Just haven't given it a lot of thought lately.

To the OP, I have an Adept22 I have been gonna sell if you are interested.
 
I swap.

Will need to be much closer to my retirement goals before an altimeter for every rocket happens.
 
Dedicated! There are so many altimeters out there at very low prices, particularly the DIY ones. It’s much more convenient and practical to have a specific installation in each, particularly with many different body diameters. However, having said that, there is logic in swapping over complete avbays in between the same body sizes. I would normally only swap over for the expensive avionics, though.
 
I used to swap, but since I have pretty much gone to all 3D printed sleds, I get a new $49 Perfect Flight altimeter for every dual deploy rocket. I have been plagued with deployment failures in the past, and going dedicated brings me one step closer to mitigating failures due to wear and tear on electronics.
 
I swap between sleds for special rockets, but as much as possible I try to share sleds. I have a sled for my 2.6/3" rockets, one for my 4" rockets, and a setup for my 5.5 and up rockets that use a different base in each rocket (to accommodate the different dimensions) but a sled that swaps between those bases with just 4 screws. Same wiring connectors, so a fast swap. That ends up as 3 sets of redundant flight computers (I fly Raven/TeleMetrum combos). You do need to pay attention to flight parameters (main deployment altitude, etc) which is why I try to do it in sets - all the 4" rockets use the same flight parameters, as do the others.

David
 
We choose dedicated with NO swapping. Wayco and I launch alot. We flew nearly 50 days this year with over 200 flights between the two of us. I counted 53 altimeters since we fly (most) of our dual deploy rockets with redundant altimeters. We want to maximize our launching time, maintain consistency in flight parameters and minimize potential damage moving altimeters between rockets. We plan ahead each year as to which new rockets will be built and try to buy altimeters during sales (and never quite get it right somehow...). But that is just how we do it. YMMV

But the OP wrote they had 2 DD rockets and one altimeter and was planning to swap instead of getting a dedicated altimeter for each rocket. That just fine until the altimeter has a problem or gets damaged (rare, but both have happened to me). Then it's really nice to have that additional altimeter. :2:
 
I run a Missileworks RRC3 and RRC2+, each with their own 54mm size sled from the same vendor, and a 110/220V switch for each on power. My HP fleet runs from 54mm to 5.5" so they will work in any of my rockets with an e-bay. My bulkheads that didn't have 1.5" center-to-center rod spacing were either sealed & redrilled or replaced. My e-bays that are long enough run both sleds; the ones that aren't run one sled / altimeter with motor backup. I have some brass tubing spacers that I use to keep the sleds from moving back (or occasionally forward if necessary) under accelleration. They are armed with a screwdriver through the static ports, which can be a bit tricky with larger BT's, but as long as I'm careful to assemble each permutation properly, it works.
 
It's all different strokes for different folks. Some people (like me) like to show up at the launch with rockets ready to go. Others like to sit around at the launch and load their rockets from scratch. I think it boils down to two questions:

  1. What do you like spending time on?
  2. What are you willing to spend money on?
 
One thing to keep in mind if you swap altimeters: if you are planing on flying several rockets and you crash the first one, what do you do to keep flying? For many of us our launch opportunities are limited so if you are swapping out altimeters at a launch and things go awry on an early flight, your might be done early and then are left with a bunch of half-prepped rockets to deal with. I use mostly Raven's and Strataloggers CF altimeters (one of each in a redundant dual deploy situation) and have enough so that I can fly all the rockets I plan to without moving altimeters. It allows for a much higher flight count and a lot easier prep at the field.

I prep everything except for adding the BP to the charge holders. That I do at the field once I know I can fly a particular rocket.


Tony
 
I used to swap, but since I have pretty much gone to all 3D printed sleds, I get a new $49 Perfect Flight altimeter for every dual deploy rocket. I have been plagued with deployment failures in the past, and going dedicated brings me one step closer to mitigating failures due to wear and tear on electronics.

+1. I have dedicated altimeters. I believe in the idea that if a process allows a mistake can happen, it eventually will. There’s less chance of me screwing up a transfer with swapped wires or a loose connection, stray strand, etc if I use dedicated altimeters. I install, connect, check, and seal it up and I know that av bay is good to go. I do have two 4” rockets that I swap the av bay between. That’s a simple matter of removing/re-installing three plastic rivets.

I’m in the group that preps rockets ahead of time so I can launch as many as possible while the range is open.

Stratologgers and RRC2+ are low cost enough, especially during sales to allow me to dedicate altimeters. Keep an eye out in the yard sale for people selling their altimeters. There's deals to be had there if you're fast enough. Electronics go quickly.
 
I am cautious of electronics in the yard sale. You don't always know how many flights, hard landings, or water submersions they had. $50 for a new one works for me.
 
I am cautious of electronics in the yard sale. You don't always know how many flights, hard landings, or water submersions they had. $50 for a new one works for me.

I think that’s a valid point. Caution does need to be exercised. The Stratologger I purchased was listed with a description of a
handful of flights and no crashes. Photographs showed it was clean with no BP residue. After receiving, ground tested it and it worked fine, downloaded the flight graphs and they all appeared to land under chute. I was comfortable flying it and it’s worked well.

Electronics are a line of safety and should be treated as such.
 
I have 9 altimeters and about 20 dual deploy rockets. All of my rockets have a 1/2" diameter rod (wood, aluminum, or steel depending on the size of the rocket) through the altimeter bay. All my altimeters are mounted on a 1.5 x 5.5 " sled with a 1/2" lug on the rear. I can put any altimeter in any rocket. I prep in advance, but never need more than 9 dual deploy flights at a single launch.
 
I came up with a easily swapable av bay sled that fits in a 54mm coupler with a 1/4-20 threaded rod though the center of it at least 5 1/2" long. I used two Eggtimer Quantums and an Eggfinder TX for tracking. No switches thanks to the quantums, just hook up the deployment changes and go! Despite the threaded rod, we've flown it over 10,000' and had no issues with tracking.
12-16-17 download 104.jpg
 
I came up with a easily swapable av bay sled that fits in a 54mm coupler with a 1/4-20 threaded rod though the center of it at least 5 1/2" long. I used two Eggtimer Quantums and an Eggfinder TX for tracking. No switches thanks to the quantums, just hook up the deployment changes and go! Despite the threaded rod, we've flown it over 10,000' and had no issues with tracking.
View attachment 334413

Er, ummmm. Helps to connect up the batteries too ya know!:wink: Kurt
 
I make my own altimeters and my own rocket motors. I do not use pyro ejection because I find it not really reliable so I have a minimum of 2 altimeters in each of my rockets single or dual deployment.
However I do swap the batteries.
 
My first av-bay was my 2" ID L1 cert rocket. The next was my 4" L2 cert rocket. I built that to be able to use the same sled and swap altimeters. My next DD was a 3" and also built for the same sled. That was about as far as swap-able altimeters went. The L1 is history and the other two rockets now have dedicated altimeters. Everything I've built since has also had it's own altimeter.

As I've moved up, the rockets get larger, the kits more expensive and altimeter have been getting cheaper for the features available. If I'm going to spend $600 on a kit, harnesses, recovery, etc. I can kick in another $60 for an altimeter.

As I write this, I realize I'm now going down the same path with GPS trackers. Building/modding to be able to swap the transmitters. I wonder how long or how many rockets it will be before I'm putting a dedicated transmitters in each rocket?
 
My first av-bay was my 2" ID L1 cert rocket. The next was my 4" L2 cert rocket. I built that to be able to use the same sled and swap altimeters. My next DD was a 3" and also built for the same sled. That was about as far as swap-able altimeters went. The L1 is history and the other two rockets now have dedicated altimeters. Everything I've built since has also had it's own altimeter.

As I've moved up, the rockets get larger, the kits more expensive and altimeter have been getting cheaper for the features available. If I'm going to spend $600 on a kit, harnesses, recovery, etc. I can kick in another $60 for an altimeter.

As I write this, I realize I'm now going down the same path with GPS trackers. Building/modding to be able to swap the transmitters. I wonder how long or how many rockets it will be before I'm putting a dedicated transmitters in each rocket?

Weeeeeelllllll..................... It's a lot easier now for a dedicated tracker than 12 years ago when Ham Radio APRS trackers a' la Beeline GPS and Byonics stuff were the only game in town and the license free rocket stuff on the 900Mhz band was > $1000.00.
The ARTS system I think was $750.00 and could be integrated into the ARTS2 and possibly the ARTS one. I picked one up second hand as I have an ARTS 2 and it can be flown by itself. Sort of ahead of it's time EggFinder on a larger footprint.

Never did read on TRF where anyone used a Microtrak: https://www.byonics.com/mt-300 although one would have to have wired in their own 5V GPS chipset which isn't that hard.

Two meter ham band would have better propagation than any other tracker flying but with most of our stuff it's overkill. The Multitronix system has certainly bore this out with the receiver antenna design and more horsepower with the usable 1 watt output on the tracker. The online videos bear this out.

At $75.00 a pop for an EggFinder it sure is easier to have a dedicated tracker per rocket than it was in the old days.

If one gets a Ham Tech license, the AP510: https://www.radioddity.com/sainsonic-ap510-aprs-tracker.html with it's high learning curve but cheap at $99.00 is a very viable APRS tracker on 2 meters and can even store the track on a MicroSD card.
Alas, it's a Sirf IV chipset and wouldn't be viable for record attempts. Has the potential for longer range tracking on a shoestring though.

Alternatively, the PicoAPRS: https://www.hamradio.com/detail.cfm?pid=H0-015928 which is quite small for a 2 meter tracker is viable with a better aftermarket antenna not the one shown. Alas it too wouldn't be decent for record attempts as it's hobbled to
60,000 feet and the German designer has stated it can accommodate higher altitudes but he's failed to write back. Also, no on device memory storage as far as I can discern. Still if one needed something to find an extreme project that was size limited
it certainly might be a candidate.

So yeah, it's a lot better to be flying out of sight projects now than 10 years ago. Kurt
 
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So yeah, it's a lot better to be flying out of sight projects now than 10 years ago. Kurt

That is most certainly true. Ten years ago the only system I had available to me was a Walston RDF. With today's electronics, its much better. I can see that when I look at the motors I fly. The rockets that used to get I motors and sometimes a J are now mostly K motors and only a J if the conditions are bad. That is holding true over most of my fleet. I do have to say it isn't all about the trackers available, some of it is because of the JLCR.
 
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