EZ-DD Build

[SkyDart]

After much consideration, I have decided to go with the EZ-DD Kit for my L1. I have looked at the LOC-IV, The T-LOC 4, the Mega Initiator and several other kits as well as a few designs that would be scratch built. I know everyone says KISS for a CERT flight and that the L1 doesn't require DD. However, while DD isn't required recovery is and with DD the rocket comes down much faster and drifts much less, making recovery much more likely as long as the rocket separates and the chute deploys. After I get my L1 I want to build some high-performance rockets where altitude is the name of the game and DD + a tracker will be a must to ensure recovery. I didn't want to build a rocket just to CERT and then turn around and build another one to learn DD. I also didn't want to try and learn DD on a scratch build and wanted a kit to put together first, so I had a better understanding of how the parts fit together and what is needed for DD. For these reasons I went with the EZ-DD. It has everything for your first DD rocket and is cheaper than any other kit + altimeter that I could find. I will get a few flights in on F and G motors, make sure I understand the DD and prepping the rocket, then I will use it to CERT.

I got the kit in last Monday and immediately inventoried the contents

I found I was missing 2 of the N-FETs for the altimeter but a quick email to Cris at Eggtimer and he sent them to me right away.

The engine mount went together quick, and I was able to get the fin can assembled minus the fillets on the fins that same night. I didn't take as many photos to document the build as I should have.


The next night I was able to get the coupler, and the AV bay assembled minus actually assembling the sled, I forgot to take any pictures of this though.

Today was my first and only day off this week so I started soldering the altimeter together and was able to complete it minus the two FET's that should be here soon.


With the board as complete as possible I took the time to go back and add the fin fillets

The fillets went on quickly and nothing left to do but assemble the sled and final assembly I decided to move forward with assembling the sled. I skipped soldering the apogee wires to the terminal block and zip tying the 9V bolt battery clip to the sled so I can easily remove the altimeter from the sled and solder the last 2 FET's in place easily once they arrive.


Only thing left to do now as tie everything together and assemble the rocket




Now to primer and paint. Still haven't decided on a paint scheme yet.

 

[Raythain]

The great thing about something like the EZ-DD is that you can even practice before the L1 flight with G (and possibly even F if you build light) impulse motors. Deployment failures at lower altitudes are more survivable, and the learning motors are cheaper.
I’ve got a modified BMS 3” of my own that has 4 DD flights on it now, and it’s been a great learning experience.

 

[velocipedecowboy]

I am also planning on doing my L1 with the EZDD I have one flight on mine with a g80 it flew very nicely on that motor. My daughter named it Goldtooth

 

[SkyDart]

I am also planning on doing my L1 with the EZDD I have one flight on mine with a g80 it flew very nicely on that motor. My daughter named it Goldtooth

I like the paint scheme; I have a hammered copper/bronze paint that I used on my Olympus. I was thinking about using that on this. I was thinking of doing rings around the CP and another 1.5 calibers forward of the CP. That way the paint isn't just for looks but has a use in verifying the rockets stability quickly at the RSO table.

How did you manage painting with the plastic rivets? Did you paint the pieces separately or did you mask off the rivets and launch lugs? What about the hole for the altimeter button, just a piece of masking tape on the interior?

 

[cerving]

Nice build thread! Your pictures are much better than mine...

One thing I recommend is using a "mouse" sander to get the laser cut burns off the fins before gluing them to the fin can. It looks much nicer, and probably helps painting (but I wouldn't know for sure because I didn't bother to paint the prototypes).

 

[velocipedecowboy]

I like the paint scheme; I have a hammered copper/bronze paint that I used on my Olympus. I was thinking about using that on this. I was thinking of doing rings around the CP and another 1.5 calibers forward of the CP. That way the paint isn't just for looks but has a use in verifying the rockets stability quickly at the RSO table.

How did you manage painting with the plastic rivets? Did you paint the pieces separately or did you mask off the rivets and launch lugs? What about the hole for the altimeter button, just a piece of masking tape on the interior?

I just painted everything separate before tying the shock cords together, also just let the paint fly through the rivet and altimeter button hole

 

[SkyDart]

The great thing about something like the EZ-DD is that you can even practice before the L1 flight with G (and possibly even F if you build light) impulse motors. Deployment failures at lower altitudes are more survivable, and the learning motors are cheaper.
I’ve got a modified BMS 3” of my own that has 4 DD flights on it now, and it’s been a great learning experience.

Wouldn’t the rocket quickly accelerate to its terminal velocity after separation. Assuming the rocket hits it’s terminal velocity during free fall what is the difference from it falling 1k feet versus falling 2k or more feet when it comes to survivability?

I’m assuming the rocket will at least separate using the motor ejection as backup if the electronics fail.

 

[SkyDart]

Got the primer on now I'm trying to figure out a paint scheme

Thought 1: GOLDMEMBER
I already have all the paint I need and painting should be simple, I would print the name on a waterslide decal.

Thought 2: Marvin (the Martian)
I would have to buy the green paint, the eyes name and logo would be printed on a waterslide decal.

Thought 3: AlienWare
I would have to buy the paint and would add the name to the top in orange or purple. It would be fluorescent/hi-vis reflective paints and maybe a glow in the dark top cote

 

[SkyDart]

Refining the AlienWare to Area 51

 

[SkyDart]

Area 51 concept 2

 

[cwbullet]

Area 51 concept 2
View attachment 665362

Great design.

 

[SkyDart]

Well guys Marvin won on the Facebook poll, I’m still torn between it and AREA 51’s second concept.

Thinking I might save the AREA 51 design for my L2.

Anywho the rocket gods or maybe other gods dealt me a rough blow today. My trucks fusebox caught fire. I was able to disconnect the battery before it got out of hand and the damage is limited to the fuse box and 1 connector on the wiring harness. That said this is gonna cost 1-2k to fix and that’s going to take my launch budget away for the next few months. So looks like Rocket launches that require much travel or new HPR engines are going on the back burner till November or December.

 

[kjhambrick]

Refining the AlienWare to Area 51
View attachment 665346

Wait !

Shouldn't that be AREA LI ?

Which could also work as a double-entendre for the purpose of the rocket ?



-- kjh

 

[SkyDart]

Wait !

Shouldn't that be AREA LI ?

Which could also work as a double-entendre for the purpose of the rocket ?



-- kjh

Been a while since I got to work on this. But my truck got fixed and I am back to rocketry.

My boy liked the green rocket, and I couldn't pass up the opportunity to fly "AREA LI" for my L1 flight so "AREA 51" is now "AREA LI".
Got started on the paint today. Thought it would be easy to spray the fins, bands and nosecone with purple and then tape and put green over. So I started down that path.


While waiting for the purple do dry enough to tape I thought I could go ahead and do the top section.

While doing this I found out the green has to have a white base coat. Once the purple dries enough to tape I will be taping it off, putting on a white base coat and then spraying the green. Also found out that this fluorescent green is really hard to get even. Hope to have this done by next Friday and will update with photos once it's done.

Next is to figure out the decals, I have the waterslide decal material to print my own but need an inkjet printer to do so. Not wanting to purchase a new printer just to print this decal set so looking into places that will let me use their printer for a nominal fee. I have a contact at the local makerspace that has said she may let me use theirs even though it is not really intended for patrons.

 

[SkyDart]

If everything goes well hoping to fly this on 10/5/24 at the AARG's launch in Hutto. GPS Drift Cast sims are looking good for earlier flights.

 

[Rob Campbell]

That has to be the most complete kit I've ever seen.

 

[Azamiryou]

Next is to figure out the decals, I have the waterslide decal material to print my own but need an inkjet printer to do so. Not wanting to purchase a new printer just to print this decal set so looking into places that will let me use their printer for a nominal fee. I have a contact at the local makerspace that has said she may let me use theirs even though it is not really intended for patrons.

Keep in mind that if your decal paper is clear, your decals will be transparent. On the green rocket, your whites will look green, your greens will disappear, and your purples will turn to a dull muck color.

If your decal paper is white, they'll look okay but you'll have to cut very intricately to remove the white background where you want the rocket to show through.

If your printer can match the green of the rocket, you can use white paper and print the green background to make the cutting out easier. I think it'll be really hard to match though.

 

[SkyDart]

Keep in mind that if your decal paper is clear, your decals will be transparent. On the green rocket, your whites will look green, your greens will disappear, and your purples will turn to a dull muck color.

If your decal paper is white, they'll look okay but you'll have to cut very intricately to remove the white background where you want the rocket to show through.

If your printer can match the green of the rocket, you can use white paper and print the green background to make the cutting out easier. I think it'll be really hard to match though.

Thank you for pointing this out, I hadn't thought about this.

My decal is transparent. At an old company I worked at we had the same issue with some of our clear decals. We got past this by printing a white background onto the decal and then printing the color over it.

Without the printer that we had capable of printing white I'll have to come up with a different solution. I may be able to cut a white piece of vinyl the same shape and size of the decals on a Cricut. Apply the white vinyl to the rocket and then carefully line the decal up over that.

Or I could use the Cricut to cut a stencil and then spray the background of the decal white on the rocket. Either option will be a test of skill and precision though.

Maybe the easiest option would be to source white decal paper, print it and then cut it out on the Cricut.

 

[SkyDart]

Well, I got impatient and sprayed the green. This green is very unforgiving and very hard to get even. 

 

[bad_idea]

Well, I got impatient and sprayed the green. This green is very unforgiving and very hard to get even.

My orange rockets are the same way. Gives 'em character, I say.

 

[Azamiryou]

Maybe the easiest option would be to source white decal paper, print it and then cut it out on the Cricut.

You can try this out with white paper to see how well it works. If there's a risk of small slivers of white showing where they shouldn't, you can add a green outline. Nominally, it would all be cut away, but if the cut is slightly off, the sliver won't show.

 

[Ronz Rocketz]

After three tries, I still haven't had a successful main chute deployment. Cris mentioned that only half charge is needed. Sure enough, the full charge blew out the back of the NC. It was a good show.

 

[kjhambrick]

Thanks Ron !

Wish I could have been there ( maybe some day ) !!

So ... did you plan for that pad-side camera to fall over to catch the H242T flame on your Desert Rat ?

-- kjh

 

[Art Upton]

Well, I got impatient and sprayed the green. This green is very unforgiving and very hard to get even. View attachment 668016View attachment 668017

It's got a Reptilian look to it ?

 

[WizardOfBoz]

That has to be the most complete kit I've ever seen.

I just finished the flight computer on the thing. It is indeed complete! The design seemed to me (keep in mind I'm just getting back into the hobby after many years) a bit idiosyncratic. But after reflection, I kind of grokked some of what Cris was doing. I learned a bit.

One thing I may do is to cut 1/2" off the top of the body tube and use it for a switchband. But that's a preference. The standard design is incredibly cleverly efficient. Both the BMS rocket kit and all the mods Cris added to allow DD.

A thumbs up for the EZ-DD. And for this build - looks like a lot of fun.

 

[WizardOfBoz]

My trucks fusebox caught fire. I was able to disconnect the battery before it got out of hand and the damage is limited to the fuse box and 1 connector on the wiring harness. That said this is gonna cost 1-2k to fix and that’s going to take my launch budget away for the next few months.

Sorry to see that.
But aren't fuses supposed to open up to prevent fires like this?
What happened?
What model truck (is there a service warning, or is this a common failure)?
Unless someone bridged a fuse with a piece of wire, this seems like an inadequate design.

 

[kjhambrick]

After three tries, I still haven't had a successful main chute deployment. Cris mentioned that only half charge is needed. Sure enough, the full charge blew out the back of the NC. It was a good show.

Ron --

How do you secure the nose cone to the forward, main chute tube ?

-- kjh

 

[Ronz Rocketz]

Ron --

How do you secure the nose cone to the forward, main chute tube ?

-- kjh

That's a sordid tale filled with sighs. In the first rocket, I missed the part in the instructions where two strips of Scotch tape is used to keep the NC from separating. I instead added masking tape to the shoulder. The recovery was fine except it landed on the road and then disappeared. I imagine whoever took the rocket was inspired and will try to figure out how to use it.

I bought two kits because they're $100 each. I built the second rocket before XPRS and launched it twice. I forgot to bring Scotch tape with me so bought a roll at Walmart in Fernley. I then forgot it in the trailer at the RV park so used blue tape with perforations. It worked fine with the first launch, but the main charge blew open the NC. For the second launch, I put too many perforations in the tape but was a beautiful recovery in the desert (with a borrowed Leviathan NC). I repaired the NC with a bulk head.

Yes, sheer pins are the preferred method. Cris told me he doesn't believe the tube can take the sheer force. It's possible to strengthen the tube with thin CA, maybe.

 

[SkyDart]

Sorry to see that.
But aren't fuses supposed to open up to prevent fires like this?
What happened?
What model truck (is there a service warning, or is this a common failure)?
Unless someone bridged a fuse with a piece of wire, this seems like an inadequate design.

I think the board on the inside got corroded and created a bridge from an unfused positive post that goes straight to the battery and a ground terminal that provides a ground for the relays. I had some issues with other circuits just before this happened where the circuits were receiving power when they shouldn’t have been. All the affected circuits had fuses around the ground terminal and the same positive bus

 

[bad_idea]

Yes, sheer pins are the preferred method. Cris told me he doesn't believe the tube can take the sheer force. It's possible to strengthen the tube with thin CA, maybe.

The BMS tubes are 0.035" thick. I can't bring myself to trust a cardboard tube with shear pins, even with CA, and especially one that's thinner than typical high power tubing. I fiberglass shear plates of 0.005" stainless steel shim stock into the break points of cardboard DD rockets, and onto the shoulders of light plastic nose cones like the BMS cone too. (Looking at heavy plastic high-power nose cones like those from LOC, I doubt they need anything but a hole drilled.)

I'm planning to get an EZ-DD at some point and build and fly it stock to see how well the tape method works, but I'll probably install plates at some later point (will also mod the nose cone to fly an Eggtimer Mini).