Is it my RRC2+ or the way I am testing it going wrong?

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DAllen

DAllen

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So I have a mason jar with a syringe glued to the lid. I put alts in there to simulate flights and can generate enough pressure differential sims to 1k to 2k - usually. I hook up xmas lights to stand in for charges and is a good visual for when the charges are triggered. So the procedure is, turn on the alt, put in the jar, attach the lid with the syringe in it and pull out the syringe and push it back in. What normally happens is when I stop the syringe the main light turns on then as I start to push it back in the drogue light turns on.

Now I am testing my newly acquired RRC2+ and RRC3 and both are doing something weird. Both are turning both lights on at the same time after I push the syringe all the way in. Then instead of beeping out an altitude they are just beeping. A lot. Not beeping an altitude - just continuous beeping. So I am thinking my method of testing is flawed but cannot find anything in the manuals for either addressing this continuous beeping. Was wondering if anyone had any insight as to what is wrong here. My suspicion is the test is not developing enough negative pressure to truly simulate a flight but would love it if someone could confirm.

FYI I did email Missleworks with this same question but am hoping someone could provide an answer soon as I am trying to iron some things out.
 
I do the same thing, although I use the Adept jar and syringe system. One thing I noticed, which may have just been a brain fart, was you said your main light was turning on at apogee and drogue during descent.

What I would do is take an older, trusted RRC and test it in the same way you are doing the new ones. If it acts weird, then it's your method. If it acts normally but the new ones don't, then something is wrong with the new ones.

Let us know how it goes.
 
Draw the syringe slowly...pause...push the syringe slowly.

Download the data and see what the altitude looks like.
 
Okie dokie...MW responded already! I was not expecting THAT lol. Anyways, they basically said with my setup it might be confusing the software because I might be pulling the syringe in and out (as Buckeye suggested) too fast. So I slowed it down and it worked - sorta. I got one simulated flight to 2100' and the lights went on as they should. Then I tried the RRC2+ and got it to beep out an altitude of 197'. Yeah so that tells me I need a new altimeter test rig and the altimeters are probably fine. I am guessing I am getting an inconsistent and/or not very good seal.
 
DAllen said:
Okie dokie...MW responded already! I was not expecting THAT lol. Anyways, they basically said with my setup it might be confusing the software because I might be pulling the syringe in and out (as Buckeye suggested) too fast. So I slowed it down and it worked - sorta. I got one simulated flight to 2100' and the lights went on as they should. Then I tried the RRC2+ and got it to beep out an altitude of 197'. Yeah so that tells me I need a new altimeter test rig and the altimeters are probably fine. I am guessing I am getting an inconsistent and/or not very good seal.
Click to expand...
If you have a Foodsaver or vacuum pump its easier to get repeatable results. I use a food saver marinating container and the food saver hose end (the pump died on the FS), with my vac pump and the valve on the container its pretty easy to get 30k plus simulated flights and both events.
 
Ooooohhh a foodsaver. I can hear it now:

"Did you seriously con me into letting you buy the foodsaver just so you could test your altimeters? SERIOUSLY?"

"Uhhhhhh...maybe."
 
It's very common for both lights to come on "simultaneously" when you're using a setup like that, or with a vacuum cleaner. The problem is that the vacuum drops so rapidly that there's very little difference in time between "apogee" and your main deployment "altitude" pressure. This is especially true if you can't pull enough vacuum to simulate at least 5K. The channels don't actually fire at the same time, but there may be a few hundred milliseconds or less between them. I can't count the number of times that I've had people send me a support request over the past seven years saying that their Eggtimer altimeter fires both channels at the "same" time while doing a vacuum test... if you look at the actual "flight" data, you can see what happens. Although I don't have one, I assume you can do this with a RRC3+ too since it's a datalogging altimeter; the RRC2+ doesn't log data except for apogee, similar to an Eggtimer Quark, so you'll just have to take my word on that one.
 
HVArcas said:
why are you guys ground testing altimeters anyway.. flight test!
Click to expand...

The altimeter itself is very robust and not likely a failure point. It is good straight out of the box. I only vacuum test the altimeter outputs if I did something stupid, like suffer a hard landing.

I use the computer interface to ground test batteries and ematch compatibility with the altimeter.
 
DAllen said:
lol cause its for my L3 and I am paranoid.
Click to expand...
yeah but is a ground test even a good check for that?

I am dead serious about flight testing - I fly 2-4 altimeters all the time, with dummy charges on the ride-along boards. When I say it in a kinda-joking way I guess it sounds like I am saying, throw caution to the wind, and fly without testing first (which I sometimes do), but it does not have to be that way.
 
HVArcas said:
yeah but is a ground test even a good check for that?

I am dead serious about flight testing - I fly 2-4 altimeters all the time, with dummy charges on the ride-along boards. When I say it in a kinda-joking way I guess it sounds like I am saying, throw caution to the wind, and fly without testing first (which I sometimes do), but it does not have to be that way.
Click to expand...
Another advantage to vacuum chamber testing is verifying that you actually programmed the altimeter correctly, as far as the alt knows its in a rocket going "up", it detects "apogee" and fires drogue charge, then "descends" and fires main at set altitude, all without leaving the bench. Ground testing really just tells you if the charges are going to do their job. A vacumm chamber allows you to actually watch the altimeter do its job.
 
HVArcas said:
yeah but is a ground test even a good check for that?

I am dead serious about flight testing - I fly 2-4 altimeters all the time, with dummy charges on the ride-along boards. When I say it in a kinda-joking way I guess it sounds like I am saying, throw caution to the wind, and fly without testing first (which I sometimes do), but it does not have to be that way.
Click to expand...
A ground test is good for making sure that your baro sensor is working and that your battery will fire your charge... and that's basically it. I totally agree with you about ride-along flight testing, I do it with every altimeter I build, and of course I do a lot of it when I'm testing new Eggtimer software. Once I'm 100% sure that it's doing what it's supposed to do, it goes into an AV bay.
 
rharshberger said:
If you have a Foodsaver or vacuum pump its easier to get repeatable results. I use a food saver marinating container and the food saver hose end (the pump died on the FS), with my vac pump and the valve on the container its pretty easy to get 30k plus simulated flights and both events.
Click to expand...
Link to preferred marinating container please? :)
 
rfjustin said:
Nice! Thank you sir.

I take it you can vent it slowly using the twist cap on the top?
Click to expand...
Yes, that how I use it. It does require the Foodsaver canister hose fitting. My Foodsaver pump died so I cut the hose off and use it with my Robinair Vacuum pump. You can see the Foodsaver hose between the valve and the bag fitting, its the black plastic part.
20200430_063940.jpg
 
rharshberger said:
Yes, that how I use it. It does require the Foodsaver canister hose fitting. My Foodsaver pump died so I cut the hose off and use it with my Robinair Vacuum pump. You can see the Foodsaver hose between the valve and the bag fitting, its the black plastic part.
Click to expand...
Sweet, thanks!
 

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