Level 3 Build:Red Dragon

[cdondanville]

So here is a build thread that I will be posting on as I progress on this build. This rocket is going to be my LVL3 certification bird. It will be mostly scratch built fiberglass with some plywood for centering rings and bulkheads. I bought the nose cone from Public Missiles, but I will be rolling the fiberglass tubes with the help of one of my TAPs. I am planning a traditional dual deploy, with an electronics bay in the middle, drogue aft and main in payload. rolling the tubes and coupler for the bay will be time consuming and I have to schedule time with my mentor to do them (thanks Walt) but I hope to complete construction this spring.

Special shout out to my TAPs for their patience, support and assistance as well as the members of Phoenix Missile Works for all their advice and suggestions.

Walt Stafford (Prefect Tripoli #81 Birmingham, AL)
Bob Haas (President Phoenix Missile Works)

and my 1st alternate TAP:

Chris Short (Prefect Tripoli Central Alabama #38)


Some essentials of the project:

Length: 110" or just over nine feet.
Diameter: 6" id airframe
Electronics: Dual PerfectFlite Stratologger SL100
Motor: 98mm Cesaroni Pro98 (3 grain)
Fins: 4 (sorry Tom) right triangular @ 1.5 caliber, surface mount
Target Weight: 28-30 lbs packed before motor




Red Dragon.ork

[cdondanville]

I have 2 flights planned for this bird. A shakedown flight and a certification run. I am getting my motor reloads and hardware from Carey Huff at Huff Performance. The motor is a 3 grain Cesaroni Pro98 case. The planned flights are to be on an L610 and an M520. Yes I said M520. Lets Have a look using a weight of 30 lbs packed before motor:

4842L610 Classic
---------
Weight on the pad: 40.7 lbs
Max Thrust: 210 lbs
Thrust to Weight (max) 5.16
Apogee: 6140'
Max Velocity: 393 mph (Mach 0.52)
Acceleration (max) 4.16g

7400M520 Classic (Moonburner)
----------
Weight on the pad: 44.7 lbs
Max Thrust: 267 lbs
Thrust to Weight (max) 5.97
Apogee: 9899'
Max Velocity: 460 mph (Mach 0.61)
Acceleration (max) 4.43g

Both of these motors have relatively low average impulse for their classes, but they both have a nice initial kick off the pad with the max thrust being way up front on a partially to completely regressive thrust curve. As long as I can keep the weight of the packed rocket under 31 lbs, I should keep a nice 5:1 thrust:weight ratio as I come off the pad. I am shooting for 29 lbs, which should put me just over 10k for the certification flight. It also keeps me well below Mach, which was a goal, I do not want to add that complication to the flight profile for a certification run.

Pro98_dimensions.pdf

L610 Thrust Curve.pdf

M520 Thrust Curve.pdf

[cdondanville]

I ordered a 6: fiberglass nose cone from Public Missiles. I chose them because I had a gift certificate that I won at a raffle! Well that and I know that they have great stuff.



The nose cone came with a plywood bulkhead with an attached U bolt. I took the U bold off and threw it in the parts box. I then drilled a 3/8" hole in the center of the bulkhead, between the 2 U bolt holes and I cut out a 4" diameter piece of 1/2" plywood that would serve as an internal bulkead. It also had a 3/8" hole in the center.

I poured a generous amount of epoxy into the tip of the nose cone then inserted a 3' x 3/8" threaded rod into the nose cone seating it in the epoxy. I then threaded the 4" bulkhead over the rod and slid it down into the nose cone until it seated against the interior walls of the nose cone. (I beveled the edge so it would conform to the contour of the wall of the nose cone and provide a better seal. I then poured another generous amount of epoxy into the nose cone to cover the interior 4" bulkhead. The bulkhead ended up being about 17" from the bottom opening of the nose cone. I threaded the top bulkhead on to make sure everything was centered and let the epoxy cure.



I then created the sled that will serve as the holder for the tracking device. I have not secured tracking, but I know that this will give me a nice place for the bug and the antenna. I used a long thin piece of 1/4" plywood for the sled. I attached 2 small blocks of wood with 3/8" holes on the underside that serve as guides and to hold it securely to the threaded rod. I then fixed the sled assembly to the read bulkhead. I put 2 1/4" eye bolts through the holes where the U bold was attached these will serve as handles for extracting the sled/bulkhead assembly when it is secured and also as a point to tie off the 3/8" eye nut that will serve to secure the bulkhead/sled into position, and also as the attachment for the main recovery harness. (I will tie off the eye nut to the eye bolts to prevent the eye nut from spinning off during recover. Hey, it could happen.

[dixontj93060]

Will be following this build... PML fiberglass nosecones are nice, aren't they?

[cwbullet]

I like the tarcker sled. What are you usign as a tracker?

I would look at your motor selection. With a M520, I would not recommended going above 23-26 lbs.

[cdondanville]

I like the tarcker sled. What are you usign as a tracker?

I would look at your motor selection. With a M520, I would not recommended going above 23-26 lbs.

I do not have the tracker yet, but want to use GPS as opposed to RF. I am looking at the Garmin Astro and the Big Red Bee as possibilities. The Astro is very appealing for its rugged design and ease of use on the field so I am leaning that way, but am still open for options.

I think the math works out on the M530 up to about 30 lbs (and actually the L610 test is probably the limiting factor). My design looks to be about 27 lbs right now. Since I am way over stable, I can always cut down on the length of the payload to trim some weight. I am leaning towards the moonburner for budget reasons. Cary has the case and motor that someone ordered and the reneged on the deal. He is willing to let me have it on a deal since it is kind of an odd ball to have in inventory! I also like the low velocity and stress it brings to a certification flight. Less extreme flight profile, but as you point out, it is a little extreme in the other direction.

[Stymye]

sounds great so far Chris .. will you be flying it at MC2?

[cdondanville]

Question: thinking of putting some screws through the airframe into the centering rings to add a little support against the shear between the ring and the airframe. Looking at a counter sunk #6 x 3/4 machine screw. My only worry is weakening the airframe (0.1" fiberglass) or the centering ring (1/2" birchbark plywood). Any comments on this construction technique?

[cdondanville]

And BOOM! Mark comes through with PERFECT graphics.

[Eat, sleep, and Fly]

And BOOM! Mark comes through with PERFECT graphics.

Beautiful!!!

[[POW]Eagle159]

N I C E ! ! !

That turned out perfect!

[cdondanville]

Ok, thought I would provide an update. I took Red Dragon to Phoenix Missile Works the end of March and flew her twice. The first flight on a CTI L610 was picture perfect. About 6300' and recovery in the field about 500 yards from the pad. So I packed her up again and loaded an M520 and put her up again. The up part was perfect, however the main never inflated. It knifed a fin into the red Alabama clay and ripped it loose as the body fell sideways to the ground. Ouch. No cert for you!

So I took her home and ripped the fin the rest of the way off and remounted it. I reinforced the fin can all the way around with another couple of layers of glass. Sanded primed and painted. Begged the wife and another m520 was my birthday present. Did quite a bit of research and some more ground testing to make sure I had a good chute strategy, and recovery packing.

Next chance I had was in Manchester at the HARA research launch, May 20. just before noon she was ready to go. She took off with a little wiggle but then disappeared into the haze. Got the next visual of her as she was under main at about 1100'. She came down in a field about 2500 yards from the pad. I had to wade throug about 600 yards of blackberry bushes, but she was laid out perfectly in the field and in perfect condition.

Successful L3 certification flight. 10,750' on a CTIM520 Moonburner for the 27lb scratch built fiberglass airframe. Boo-ya!

[nh4clo4]

CONGRATS!!!

Very nice rocket and a very cool choice of motor for a cert flight.

[cdondanville]

http://www.youtube.com/watch?v=VB4Wi...e_gdata_player

Video of the second flight. This is the M520 with its 14 second burn.

[Coop]

Congratulations! Well-done!

Later!

--Coop

[COrocket]

What did you end up using for tracking? I was curious because I just invested in a Garmin Astro for my rocket, and i was wondering how the Astro/Stratologger combo works.

[grouch]

Wow, how did I miss this thread? Great job Chris!!! You have had a great year in rocketry!