Twitch Dual Deploy Level 2 Build Thread

[Lowpuller]

I'm building this bird for my level cert flight.



I bought a few extra parts but still need recovery hardware

 

[Lowpuller]

The inspiration for this started in 1999 when I got this October copy of high power rocketry for free!



I had no idea what Level Two was but this ad got my attention.



I actually bought this right after I got my Level 1 and have selected the rocket around it.



I know everyone says go low and slow and simple on a cert flight............but I've had this plan for a long time.

 

[Lowpuller]

Motor tube assembly



Recovery attachment via finger trap

 

[watermelonman]

I know everyone says go low and slow and simple on a cert flight............but I've had this plan for a long time.

It is all about what you want to do. I did 8k, supersonic, on cardboard for my L2. One of my friends topped 20k on an L with fiberglass, and possibly my craziest friend set the period Tripoli N record with his first flight of a prototype tracker for L3.

Best wishes and looks good so far!

 

[Lowpuller]

AV Bay sled constructed, bulkheads drilled, test fit and switch band mounted.



Test fitting of fins. I used an emory board to widen the tube slots. I am also not going for altitude so I intentionally left the fin edges square.



I don't know way I did this next but I attached the main bridle to the nose cone. I think I only had a few minutes and wanted to get something done. This is the nylon that came with the kit but I think it too bulky for the size main I want to use but leaving it for now. I already replaced the drogue bridle with some Kevlar I had on hand.



I always tack my knots, old parachute rigger habits die hard. I was also concerned about a metal link on the plastic.

 

[terryg]

Do not trust the thin loop that is on most plastic nose cones to hold the shock cord. It will break on you at some point. Drill two holes on either side and run a loop thru to make an attachment point or use an eyebolt.

 

[Lowpuller]

Thanks for the advice, I've been worried about the loop.

 

[Lowpuller]

While I was waiting for the motor mount to dry in the booster section I worked on the nose cone. The nose cone had two really rough low spots where apparently mold marks were removed. I puttied them up.





Time to attach the fins:

One fin



Two fins





Three fins.





I drilled my AV Bay rivet holes, now it's time for paint.

 

[Lowpuller]

I set my paint booth up (time lapse video of the step up, under Techniques). It took less than 7 minutes to set up my booth including bringing it in from my other garage.



The primer went on beautifully.







Then I top coated with a Rustoleum Satin finish and then wanted to cry. I had waited 48+ hours but I still got bubbles. Lots of bubbles and the finish was shinier than I wanted. Time to fill and sand.

 

[Lowpuller]

Top coated with Krylon flat black, just what I wanted. Debating above covering with a matte clear coat. It looks just like I want so I'm hesitant to screw it up.



StickerShock on the way.....

 

[Lowpuller]

Moved on to building my Eggfinder TRS and LCD covered in a separate thread. Awesome documentation and customer support. I was hesitant to take the Eggfinder on but it turned out to be a very challenging and rewarding experience.



Now it is time to tackle the AV Bay.



I intend to lengthen or rebuild this sled. Eggfinder and LiPo on one side and RRC2+ with 2 nine volts on the other side. One of the nine volts will provide deploy power for the Eggfinder. I also plan on adding Missile Works screw switches.

I'm waiting on parts from MW so work goes on hold for a while. I also have to wait for my November check to buy recovery parts.

I really want to use a 60" or bigger main but I'm worried I don't have the volume.

 

[Lowpuller]

Here is a sneak peek.



Getting ready to drill the nose cone vent, AV Bay vents, and add rail buttons.

 

[Lowpuller]

????????

My motor casing wiggles/slides just a little after I fully tighten my AeroPac retainer. I found that adding a thin o-ring just ahead of the rear closure tightens everything up nicely.

Anyone see a concern with adding this o-ring???

 

[Tonimus]

Nah, you'll be fine.

 

[Lowpuller]

Should it fit tight or is the wiggle normal?

 

[Tonimus]

A little wiggle isn't always abnormal. Stacking tolerances and the like.

 

[Tonimus]

If it really bothers you, you can knock down the edge of the inner part of the Aeropack that butts up against the screw on retainer.

 

[Lowpuller]

Finally got a little rocket time. I've been focused on the AV bay but can't make my mind up about how to put it together I think I'm gonna make a longer sled than what came stock.

For now I moved on to recovery. I have what I need except for a main canopy so I put the drogue together.

 

[Lowpuller]

I attached the harness to the motor mount prior to gluing in the motor mount so now I added a swivel to the booster section. I'm probably a little to long between the booster and the swivel but I'm gonna give this a try.



I'm about 8" from top of the booster to the swivel.



I only have a single needle sewn machine so I use this cheater device to sew the materials.



Here's the finished product.



Here is a short video showing how I do my finger traps.

https://youtu.be/h8QE8dTEi64

And the finished product



I need to add a picture that shows the full harness, drogue, blanket, etc....

Used a 14' harness fro the drogue. I'm not gonna make the main harness until I buy the parachute, anybody got an old parachute in the neighborhood of 60" you want to sell???

 

[Lowpuller]

I also added my rail buttons today, the top rail button is located at the CP



This is the final paint, flat black and yes it is that rough, not going for altitude records here!

 

[Nick@JET]

Nice instruction, never thought of that, nicely done

 

[mpitfield]

I know everyone says go low and slow and simple on a cert flight............but I've had this plan for a long time.

Not everyone is of that opinion. You will see that some believe the certification process is all about the end game of the certification and do not take any unnecessary risks. Then there are others like myself that believe the best time to take the risks is when you have the most at stake. Why, because this is personal, it's just a hobby, I learn more from my failures than my successes, and it is certainly more rewarding for me when I do so regardless of the outcome.

BTW, what flat black is that, it looks nice. I recently discovered the Krylon camouflage for flat black and it is so easy to work with and has great results.

 

[Handeman]

I attached the harness to the motor mount prior to gluing in the motor mount so now I added a swivel to the booster section. I'm probably a little to long between the booster and the swivel but I'm gonna give this a try.

I only have a single needle sewn machine so I use this cheater device to sew the materials.

View attachment 303860

Here's the finished product.

View attachment 303861

And the finished product

View attachment 303862

I need to add a picture that shows the full harness, drogue, blanket, etc....

Used a 14' harness fro the drogue. I'm not gonna make the main harness until I buy the parachute, anybody got an old parachute in the neighborhood of 60" you want to sell???

very interesting the aid you use to sew the cord. I'll have to try that.

I do have a suggestion, and that is to use a ball bearing swivel like this one https://www.spro.com/ProductDetails.asp?ProductCode=SBSB2WR-ALL

I've had a #8 size one on my 4" 10 lb. L2 rocket since 2009 and through 34 flights. It's still as good as new.

I did try a swivel that looked like the one you have there on a smaller 3" L1 rocket and it was deformed on the first flight. Hope that one works for you, but keep an eye on it.

 

[REK]

I attached the harness to the motor mount prior to gluing in the motor mount so now I added a swivel to the booster section. I'm probably a little to long between the booster and the swivel but I'm gonna give this a try.

View attachment 303858

I'm about 8" from top of the booster to the swivel.

View attachment 303859

I only have a single needle sewn machine so I use this cheater device to sew the materials.

View attachment 303860

Here's the finished product.

View attachment 303861

Here is a short video showing how I do my finger traps.

https://youtu.be/h8QE8dTEi64

And the finished product

View attachment 303862

I need to add a picture that shows the full harness, drogue, blanket, etc....

Used a 14' harness fro the drogue. I'm not gonna make the main harness until I buy the parachute, anybody got an old parachute in the neighborhood of 60" you want to sell???

Sweet now I have an excuse to use the sewing machine.

Thank you for sharing.


Sent from my iPhone using Tapatalk

 

[Lowpuller]

Finally got to work on my AV Bay.

Eggfinder and RRC2+ mounted on one side with a screw switch for the GPS and a screw switch for the RRC2+, cables still need to be secured



The other side holds the batteries, 2 nine volts for deploy charges and a LiPo for the GPS. I didn't order enough screw switches but the board is ready as soon as it arrives from Missile Works.



The screw switch for the GPS can only be accessed inside the AV Bay. The screw switches for the deploy charges will be accessed through the vent holes that will be placed in the switch band.

It's tight in there!!



I still need to install the well seals in the bulkheads for the ematch pass throughs and finish and mount the charge canisters. I think I plan to use modified 30-06 and 38 Special Brass.



I do have a problem. I drilled my rivet holes first, big mistake in hind sight as the rivets interfere with the electronics. I have considered abandoning these as rivet holes and using them for my vent holes. However I need at least 2, 1/4" vent holes in the switch band for deploy charge screw switch access. I would then relocate the rivet holes to a clear portion of the AV Bay.

Can I have to many vent holes or rather too much vent area? I calculated needing 3, 1/4" vent holes, if I abandon the rivet holes and add the two new switch holes I will have 5, 1/4" vent holes total on a 3"x 9" AV Bay that is jammed full.

Please let me know your thoughts on the vent holes.

 

[Lowpuller]

I have been estimating 7lbs. - 10lbs. but it looks like I will be closer to 6 pounds, so much for keeping her low.

I still need a bargain on a 48" - 60" chute, please let me know if you have an old one your ready to unload!

 

[RocketFeller]

I know everyone says go low and slow and simple on a cert flight............but I've had this plan for a long time.

I took their advice to heart - 1920' on an L850W...

 

[DGBrown]

Could you fit pem nuts in the rivet holes for retention? Those should protrude significantly less than rivets.

 

[Lowpuller]

So can I have too many vent holes or too much area?

 

[Lowpuller]

Bump, seeking vent hole advice, I've gotta make some kind of modification.....


I do have a problem. I drilled my rivet holes first, big mistake in hind sight as the rivets interfere with the electronics. I have considered abandoning these as rivet holes and using them for my vent holes. However I need at least 2, 1/4" vent holes in the switch band for deploy charge screw switch access. I would then relocate the rivet holes to a clear portion of the AV Bay.

Can I have too many vent holes or to much area, can that create a problem?