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altimeter selection for DD
#1
Well, now that I have my level 2, it's time to work on DD! I have been looking at a number of altimeters for DD, and it's a bit mind boggling...

The ones that seem to have caught my eye are the Perfect Flight Stratologger, Missle Works RRC-2, Adept ALTS-25, the ARTS 2, and maybe one of the transolves.
Anyone have any bad experiences with any of these, or recommendations based on good experiences with any of these?

I do plan to use 2 (from different manufacturers), so I will have redundancy, and as a bonus, I will be all set if I decide in the future to go L3.

What I thought I would do is mount one on one side of the sled (using a LOC sled), the other one on the other side. Would plan on two battery sources, and 1 or 2 switches (1 if I can get a DTDP switch).

I realize an open ended question like this may generate a Chevy vs Ford discussion, but I am sincerely interested in knowing what has worked for folks!

Thanks in advance,

Greg
Greg Young - L3
NAR #42065
TRA #00234
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#2
Almost forgot to mention that I plan to use a beeline transmitter to avoid a potential rocket loss (the 400 Mhz unit). Will that affect any of these altimeters, or interfere with the charges, etc?

Greg
Greg Young - L3
NAR #42065
TRA #00234
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#3
Greg,

    You are right - everyone has their own preferences.  Mini-RRC2 is a good unit, I used one to get my L1 and my L2.  (Yes, I flew Dual Deploy for my L1).  Easy to set, easy to mount.  No Mach intelligence, though, so be sure to set that lockout if you are approaching Mach.  I still fly mine almost every launch.  It records the altitude, max speed and Time to Apogee for each flight. Adept 22?  I'm a believer.  Inexpensive, small and mach intelligent.  Saved my L3 attempt when my other altimeter reset itself at apogee.  Super easy to set with a couple of jumpers.  Just be sure to buy a mounting kit when you order the altimeter as it is smaller than most.  Check out the MARSA54 as well - made by MARS' own John Dermiggio.  4-channels to support any deployment scheme you can think up, built in LCD screen for easy programming at the field, mach intelligent as well.  Many club members have flown it.  I own one but don't know where it is, so haven't flown it yet.  Others will chime in on what they fly and the advantages or disadvantages.
    BRB transmitter is the way to go.  Most of the club flies those units so there are a lot of receivers, beam antennas and knowledgable users around for every launch.  Plenty of help for the asking.  Haven't seen an issue of interference yet but perhaps others have?

Dale
Dale Stoyer - L3
NAR #91256
TRA #13499
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#4
I have used a Perfect FLight Stratologger, and find it to be an excellent choice for the money, especially if you want to study telemetry data. It is built very well. Mine has survived a crash and 2 shreds.

If you want reliability on a budget, my Adept 22 has done admirably in the 2 flights I have flown it. The drogue fires at apogee, and the main fires at 600' unless you manually insert jumpers in different slots to change it to 300', 900', or 1,200'. Since everything is for the most part preset, the opportunity for error is diminished. You cannot connect it to your computer and it will not measure speed, but it will beep out altitude. Not bad for $39.

I have just started using the BRB transmitter and it works very well. The Yagi antenna plans they provide are also simple to understand, and it does a very good job.
Evan Brown
NAR# 92851
Level 2
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#5
The beeline lets you do silly things and get them back.  My weasel flight on Sunday was a vanishing act to 4k, drove out into the farm fields and the radio took us directly to it.  If it wasn't for Dennis's sharp eyes to spot it just before it landed, we'd have missed the whole flight and would have been 100% on the radio.

Consider what size rockets you're going to fly as you choose altimeters.  I have been heading backwards towards smaller rockets (cheap high-performance flights) and I bought a Raven.  It will fit in a 29mm tube AND it's powered by a single tiny LiPo cell.  Some devices are rated to run off 9v batteries and if you want to go small the power supply becomes a limit.  LiPo batteries can bring with them some other issues, but you can't beat them for size.

Reviewing the flight data is entertaining, and accelerometers provide some good data on top of the barometric sensor.

Nat
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#6
MARS members get a stupidly rediculous discount on MARSA54's.  PM me for details.

There has never been a deployment failure at Geneseo with a MARSA involved (except for Goggins who doesn't count).

Bird altimeter wiring is odd and increases the chance of error, only get one if you fly those dinky rockets like Nat does.  Old guys like us should never fly a rocket that you can't comfortably stick your arm in. Lipo batteries for altimeters are also silly.  Save that lithium for the psyhopathic medication we will all need someday.

Don't get a baro only based altimeter if you even plan to break or get close to mach.  It will fail you eventually.

--jd reporting from Shanghai
John Derimiggio
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#7
(08-22-2012, 02:45 AM)jderimig link Wrote:Don't get a baro only based altimeter if you even plan to break or get close to mach.  It will fail you eventually.

Is this from forgetting to set a mach lockout/inhibit on that one flight, or is there evidence that subjecting the sensors to mach flight will cause eventual failure?

The Raven is wired oddly-  it uses a common positive.  I wired it wrong the first time!  If the altimeter stays wired up to a home-brew harness there is little chance of getting it wrong.  I wouldn't pay that much for an altimeter unless, like JD says, you're going to fly dinky *cough* $18 motors *cough* little rockets. 

N
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#8
Nat makes an excellent point.  Flying rockets out of sight is cheaper if the rockets are smaller (and have a tracker so you can get it back).  I happen to agree with J.D., though,  that rockets should be large enough to stick your hand into.  That is why John's MARSA54 is larger than most altimeters - to discourage flying tiny rockets.  Or was that just a coincidence?

Dale
Dale Stoyer - L3
NAR #91256
TRA #13499
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#9
(08-22-2012, 09:08 AM)Nat Kinsey link Wrote:[quote author=jderimig link=topic=303.msg3415#msg3415 date=1345617953]

Don't get a baro only based altimeter if you even plan to break or get close to mach.  It will fail you eventually.

Is this from forgetting to set a mach lockout/inhibit on that one flight, or is there evidence that subjecting the sensors to mach flight will cause eventual failure?

N
[/quote]

Yes.  There is an opportunity for error in setting the mach delay and eventually (if you fly enough) that will bite you.  Baro based altimeters with 'special' software to automatically deal with mach (like Adept) will also eventually be fooled.  Again no guarantee that a failure would happen but the extra opportunity for a failure exists and there are enough other opportunities for rocket flight failures to be adding another one if you can avoid it.
John Derimiggio
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#10
(08-22-2012, 09:33 AM)Dale Stoyer link Wrote:Nat makes an excellent point.  Flying rockets out of sight is cheaper if the rockets are smaller (and have a tracker so you can get it back).  I happen to agree with J.D., though,  that rockets should be large enough to stick your hand into.  That is why John's MARSA54 is larger than most altimeters - to discourage flying tiny rockets.  Or was that just a coincidence?

Dale

Correct.  I am designing the new MARSA98 now.  Everyone is going to want to have this model with the features I am including.
John Derimiggio
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