The Eggtimer EZ-DD Rocket/Altimeter, a Complete Dual-Deploy Package for $100

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I wonder if I can use this model to get my 20 yr old son interested. He's already on the hook for helping me track staged flights.... hmmm. More than anything I think I want to build it so I can still say "I've built at least one of everything Cris makes" 😆
 
Has the shock cord been changed from what comes stock on the 3" School Rocket? I built one to see if it would make a good option for a cheap L1 cert rocket, and the use of an elastic shock cord was my only complaint. From the product description, it seems like it doesn't come with a nomex parachute protector. That might be a nice thing to offer as an optional addon.


I think that this kit might become my default suggestion for L1 certification. The stock School Rocket is quite happy flying on anything that'll fit, and the addition of a deployment altimeter is perfect.
 
Has the shock cord been changed from what comes stock on the 3" School Rocket? I built one to see if it would make a good option for a cheap L1 cert rocket, and the use of an elastic shock cord was my only complaint. From the product description, it seems like it doesn't come with a nomex parachute protector. That might be a nice thing to offer as an optional addon.
Yes, it comes with two 10' 750# Kevlar shock cords. We would have liked to include Nomex, but that would have been enough to push the selling price over $100, and chances are that anyone who's advanced far enough in hobby rocketry to build this rocket probably has some dog barf laying around anyway. You could certainly add one... but for our test flights we used dog barf. I got a 5# bucket of it to kill...
 
Has the shock cord been changed from what comes stock on the 3" School Rocket? I built one to see if it would make a good option for a cheap L1 cert rocket, and the use of an elastic shock cord was my only complaint. From the product description, it seems like it doesn't come with a nomex parachute protector. That might be a nice thing to offer as an optional addon.


I think that this kit might become my default suggestion for L1 certification. The stock School Rocket is quite happy flying on anything that'll fit, and the addition of a deployment altimeter is perfect.
You COULD read the description........
 
I think that this kit might become my default suggestion for L1 certification. The stock School Rocket is quite happy flying on anything that'll fit, and the addition of a deployment altimeter is perfect.
Same here. I can think of many times in the past couple of years when this would have been the ideal recommendation for someone moving into mid-power, high-power, or electronics. That said, this should go higher on a baby H than a giant 4" kit like many use for L1, so I'd think a tracker would be a good idea if flying it with more than a baby H at many fields.
 
Well, it goes to about 1800' on a G80, so I tend to agree with you. It sims to about 4000' on a 29mm "I"... I'm hopefully going to fly it on one this Saturday so I'll let you know for sure, but so far all of the flights that I have made have been pretty close to the OpenRocket sim (which is posted on the web site now, BTW).
 
Well, it goes to about 1800' on a G80, so I tend to agree with you. It sims to about 4000' on a 29mm "I"... I'm hopefully going to fly it on one this Saturday so I'll let you know for sure, but so far all of the flights that I have made have been pretty close to the OpenRocket sim (which is posted on the web site now, BTW).
That sounds about right. I have two rockets built on 3" OD tubing, one which should be much heavier than yours and goes to 4k on a full I, and one which should be somewhat heavier and goes to 3k on an I200. My mind sim was therefore guessing 4k or so on an I200. With dual deploy it shouldn't go far enough in reasonable winds not to be visible under main, but there's a lot of sky to search if it were to get lost in the haze on the way up.

But I bet with an H115DM, or any RMS 29/180 H, or one of the higher thrust Pro29-3G H motors, people could cert on your kit all day long on a busy field with plenty of spotters.
 
That sounds about right. I have two rockets built on 3" OD tubing, one which should be much heavier than yours and goes to 4k on a full I, and one which should be somewhat heavier and goes to 3k on an I200. My mind sim was therefore guessing 4k or so on an I200. With dual deploy it shouldn't go far enough in reasonable winds not to be visible under main, but there's a lot of sky to search if it were to get lost in the haze on the way up.

But I bet with an H115DM, or any RMS 29/180 H, or one of the higher thrust Pro29-3G H motors, people could cert on your kit all day long on a busy field with plenty of spotters.
This would be a great place to use one of Inverted Pursuit's products. Our club has Featherweight trackers to loan. Most of my tracker stuff goes in a nosecone "tube", but I've also got the Featherweight "shroud", and I'm looking at the nosecone sled system for the 3" BMS nc. (I've already got one in 54mm)
 
This would be a great place to use one of Inverted Pursuit's products. Our club has Featherweight trackers to loan. Most of my tracker stuff goes in a nosecone "tube", but I've also got the Featherweight "shroud", and I'm looking at the nosecone sled system for the 3" BMS nc. (I've already got one in 54mm)
For my own stuff, I put the tracker in the nose, but I also have a BT55 capsule for an Eggfinder Mini that can hook into any larger rocket anywhere there's a good loop for a quicklink or similar. I bring the capsule to launches just to lend to folks, rather as @SnapRoll kindly lent me a capsule with a Featherweight in it when I brainfaded and left the house without the batteries for my Eggfinder on the morning of my first L1 attempt.
 
I wonder if I can use this model to get my 20 yr old son interested. He's already on the hook for helping me track staged flights.... hmmm. More than anything I think I want to build it so I can still say "I've built at least one of everything Cris makes" 😆
My son ran out of classes to choose from this summer session so he's free and order placed. Bam!
 
The assembly instructions for the EZ-DD Rocket are now on our web site under the Support/EZ-DD tab.

We've started to ship out kits, it's going to take a few days to clear the backlog, including a few kits that we're out of. If you've ordered and paid for a kit, expect to see it in a week or so.
 
I've been saying it a lot since this thread started. Still waffling but I haven't pulled the trigger yet because I have too many rockets on the build pile.

Yeah, but I ran out of the space for more kits long before I ran out of the desire to have them.

Will I run out of the desire to have them?
 
I grabbed one as my entry into MPR. Which means I also got myself a new 29/40-120 so I could fly it (I know you can use single use motors, but this was an excuse to play with RMS).

Unfortunately it turns out csrockery can't ship the firewires internationally, so if anyone knows how to obtain them in NZ I'd be grateful for the hint. Aerospace Education have an ematch but haven't replied to my request for technical information and they're NZD $4 ea!
 
I grabbed one as my entry into MPR. Which means I also got myself a new 29/40-120 so I could fly it (I know you can use single use motors, but this was an excuse to play with RMS).

Unfortunately it turns out csrockery can't ship the firewires internationally, so if anyone knows how to obtain them in NZ I'd be grateful for the hint. Aerospace Education have an ematch but haven't replied to my request for technical information and they're NZD $4 ea!
You tried Van Tiel Propulsion for eMatches?
 
I don't know if the EZ-DD altimeter will light up a piece of shooter wire with some #40 nichrome wrapped around the leads... I'll try it and let you know. That's a case in which you may have to go with a 2S Lipo instead of the 6LR61 9V battery.
 
I don't know if the EZ-DD altimeter will light up a piece of shooter wire with some #40 nichrome wrapped around the leads... I'll try it and let you know. That's a case in which you may have to go with a 2S Lipo instead of the 6LR61 9V battery.
Thank you, that'll be helpful. There are a few DIY options I'll be able to play around with if I need to, it would be nice to have a "safe bet" though.
 
So I did a test with some shooter wire and #40 nichrome, the EZ-DD altimeter easily lit the nichrome. I used a fresh Amazon Basics 6LR61 9V battery (voltage beep-out was 9.7V). You can use that, but I would recommend dipping the head in some kind of pyrogen. I will "probably" light BP without it, but you may want to do some tests before you fly it.
 
So I did a test with some shooter wire and #40 nichrome, the EZ-DD altimeter easily lit the nichrome. I used a fresh Amazon Basics 6LR61 9V battery (voltage beep-out was 9.7V). You can use that, but I would recommend dipping the head in some kind of pyrogen. I will "probably" light BP without it, but you may want to do some tests before you fly it.
Thank you! I'll of course do some testing when it arrives, is good to know there's a backup option of I can't obtain ematches.
 
So I did a test with some shooter wire and #40 nichrome, the EZ-DD altimeter easily lit the nichrome. I used a fresh Amazon Basics 6LR61 9V battery (voltage beep-out was 9.7V). You can use that, but I would recommend dipping the head in some kind of pyrogen. I will "probably" light BP without it, but you may want to do some tests before you fly it.
Is this https://a.co/d/7Whna0w the battery you’re using?
 
My EZ-DD kit arrived yesterday. This kit is neat and robust. I had my electronics workbench already set up for another project so I knocked out the altimeter first. It’s a very simple build with all through-hole components except the voltage regulator, so I got a chance to use my reflow blower on that, just for fun. The instructions are very clear with good photographs. Cris includes several stopping points where you can test for correct assembly before proceeding deeper into the build. My sole 9V battery was petering out, but had enough power to test the electronics, which passed just fine. New 9V 6LR61 batteries on order from Amazon.

The through-hole components make this altimeter/controller very easy to build, even for a novice. Doubtless that's why Cris chose a through-hole over surface mount design.

My preference would be a LiPo battery but I can live with the 9V alkaline for now. Suggestions regarding a LiPo substitute would be appreciated.
 
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