Launch Report - First Successful Dual-Deployment Flight

[GregGleason]

Today was launch day for my Estes Ascender modified for dual-deployment. You can read about the adventures in av bay creation at this link.

I have been wanting to do dual-deployment for over 9 years, and thought this was the best opportunity to try it.

I felt well prepared and today was a great day at the field to put all the theory to the test.

I did the av bay prep and things went well. The drogue charge was set to 1.20 g and 0.96 g for the main.

The only question was how the home-brew chute protectors were going to perform. I did a test last night and there was no appreciable damage and performed well in that it released the chute.

The careful ordering of the recovery gear was surprisingly tedious, more so than building the Aerotech G64 (not that those builds are that big a deal anymore). I can see why riggers are so careful when they pack chutes for recovery.

After everything was buttoned up I weighed it and it came out to 1,032 g, which made it first rocket that I launched that weighed over 1 kg.

It was time to rack it.



Greg

 

[Tonimus]

Congrats, Greg. Welcome to the downward spiral that is DD...

 

[GregGleason]

Congrats, Greg. Welcome to the downward spiral that is DD...

Yeah, I know!

Now I could be wrong, but I think having a successful DD flight might be more difficult than getting a Level 1 cert. But I'm not sure since I'm still a Level 0.

Greg

 

[BDB]

Yeah, I know!

Now I could be wrong, but I think having a successful DD flight might be more difficult than getting a Level 1 cert. But I'm not sure since I'm still a Level 0.

Greg

That was definitely true for me!

L1 - no problem.
DD - that's where problems began. Hoping to get that monkey off my back next month.

 

[Tonimus]

Was true for me too.

 

[GregGleason]

After placing the rocket on the rail I went to arm the av bay before hooking up the igniter leads. However, the arming mechanism didn't release. After about 15 or 20 minutes of fiddling with it, it finally released and the MAWD was singing its triple-chirp song. The leads for the motor were hooked up and it was time to push the button.

The countdown was initiated and at zero the Aerotech G64 came to life.



Greg

 

[GregGleason]

I tried DD once before in another rocket and the results were mixed. You can read about that saga here. Because of that experience, I doubled down and tried to mitigate as many of the risk factors as possible. So there was a little internal drama as the day unfolded, "Did I do enough to contribute to the success of this project?" I was about to have an answer.

Since the rocket was heavier than the estimates I had given OpenRocket, I knew it wasn't going to hit the ~1,700 foot apogee.

It rose and went nearly straight up on a column of white smoke. I really like the mini-rail for MPRs.

I watched as it nosed over in the bright blue sky and saw the separation for the drogue as the PerfectFlite MAWD did its thing at just past apogee. Yep, everything looked good so far as the Top Flight Recovery 12" Thin Mill chute came out like it was supposed to and slowed the descent. Then not long after, the main charge went off (it was set to 700 feet AGL) and the Top Flight Recovery 30" chute blossomed and everything looked great as the descent was slowed to a much lower rate. And I just watched it float down and land about 100 yards away form the pad.

As I gathered up the parts of the rocket, there was no damage visible from the cursory inspection. Even the home-brew chute protectors looked like they were still serviceable and ready for another go at the sky. And I listened as the MAWD chirped out a new song: 1,162 feet.

Wow. All the hard work and planning came resulted in a remarkably great flight. A goal finally realized. Thank you Lord!

I really appreciate my club where I fly, because without them I don't think this would have happened.

Greg

 

[ksaves2]

One little tip for you Greg and all: If you want to protect your shockcord protectors a bit, get some boric acid/borax solution and mix it up in warm water. Soak some pieces of cardboard or posterboard in it and hang the pieces up to dry. You can cut a piece to parallel your shockcord protectors and lay it in there so the BP charge doesn't blow directly up the side of the shockcord protector. The cardboard gets toasted a bit but insulates the shockcord from the charge. Many times it gets blown out the rocket but so what. Cardboard is expendable.

I took two pieces of this borate soaked, "flameproof" cardboard, used duct tape to make a sleeve I put over my Dino shockcord protector. Had a motor burn-through at the forward closure as depicted here:


The shockcord protector and the borate "board" sleeve looked like this:

I tore the cardboard sleeve in two so the edges could be seen.
I was going to trash the rocket but a borescope picture wasn't too bad. Cord looks a bit ratty but I yanked real hard and it didn't break. Took the picture:


Fixed the rocket by sliding a coupler down while epoxying it in place:


I was lucky the flame coming out the hole in the motor was away from the cord otherwise it would have seared right through. Actually, the aft end of the Dino chute protector was a tiny bit melted/shrunken but I just flipped it
around so the aft end is now the forward end and it's still very intact. The rocket will fly again soon I hope.

Borate/borax soaked cardboard has many uses. One can cut circles that fit inside a bodytube and put a tab of masking tape in the center so with a long forceps can place it up against the forward closure charge. A little dog barf and
the major flame with be attenuated by the cardboard but not the charge blast. I've used this technique with great success in a short rocket like a Jart with the 29mm motor. Not much room there for a shockcord. In fact I cut a thick
centering ring and epoxied it in the nosecone shoulder with a side eyelet for the shockcord connection to the N/C. The bulk of the cord gets threaded up inside the nosecone saving the precious room for the parachute.
I use a cardboard circle as a shield with a tiny bit of barf and a chute protector. I fit a 30" chute in that space! The shockcord reeling out of the nosecone also attenuates the shock of deployment so that is an added plus.

Kurt

 

[GregGleason]

Thanks Kurt.

I omitted that I did something similar. I took paper towels and treated them with boric acid and Borax and folded them to make a pocket and placed dog barf in them. It served as the primary layer of protection between the charge and the recovery gear.

Greg

 

[GregGleason]

Here is the "after" shot of most of the recovery gear. I'm glad I had enough quick links.



Greg

 

[tmacklin]

Congratulations Greg on your successful dual deployment launch! That is indeed a milestone in this hobby and is on my bucket list...if I can remember where I put the bucket!

 

[H_Rocket]

first rocket that I launched that weighed over 1 kg

Just wait until the amount of propellant weighs that much. And the "pucker factor" remains the same!

Nicely done.

 

[Coop]

Congratulations! Gotta love when a DD flight just works!


Later!

--Coop