Canadian Level 4 Certification Build - Ultimate Wildman

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Here is the design for the avionics bay sled. The main portion of it is currently printing.


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The rocket will feature two completely independent sets of dual deploy electronics for full redundancy. The primary altimeter will be a MissileWorks RRC3. The secondary altimeter will either be a MissileWorks RRC2+ or an Altus Metrum EasyMini (the sled is designed so that either one can be used). All deployment charges will be shunted prior to arming the altimeters on the launch pad by means of two pull-pins. Each pull-pin will simultaneously control three Omron SS-5GL switches (I'm using the triple pull pin switch kits from Lab Rat Rocketry): two responsible for shunting the main and drogue charges and one to turn on the altimeter. The shunting switches will be wired in such a way that continuity across a deployment channel will not be detected by the altimeter if a charge were to somehow remain shunted. Planned wiring diagram shown below:

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Here is the design for the avionics bay sled. The main portion of it is currently printing.


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The rocket will feature two completely independent sets of dual deploy electronics for full redundancy. The primary altimeter will be a MissileWorks RRC3. The secondary altimeter will either be a MissileWorks RRC2+ or an Altus Metrum EasyMini (the sled is designed so that either one can be used). All deployment charges will be shunted prior to arming the altimeters on the launch pad by means of two pull-pins. Each pull-pin will simultaneously control three Omron SS-5GL switches (I'm using the triple pull pin switch kits from Lab Rat Rocketry): two responsible for shunting the main and drogue charges and one to turn on the altimeter. The shunting switches will be wired in such a way that continuity across a deployment channel will not be detected by the altimeter if a charge were to somehow remain shunted. Planned wiring diagram shown below:

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Outstanding. Do you have a picture of everything mounted?
 
Outstanding. Do you have a picture of everything mounted?
It took a few attempts to print it (kept getting a large and sudden layer shift with my printer 15+ hours in; eventually determined it was an overheating issue on the control board and made some upgrades/modifications to the printer to improve the cooling which seems to have fixed it).

Anyway, here are some pics with an RRC3 and RRC2 mounted. I think this is the configuration I will go with for the Level 4 flight as I have much more experience using the MissileWorks altimeters than I do the Altus Metrum EasyMini. Next thing will be to do the wiring. Black was not my first choice for the colour of the sled although it will match the paint scheme. The filament I'd ordered for this got lost in the mail for a while, though it eventually turned up (as this print was nearing completion in fact :rolleyes:).

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Speaking of paint, here is the paint scheme I ultimately decided to go with as depicted with the help of OpenRocket Photo Studio. Actually the rocket itself is already painted in real life, but I'll save the final reveal for a bit later on once I get some nice pics... :)
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(For the curious this paint scheme was inspired by the Air New Zealand livery. I recall when I flew with them a few years ago thinking that dang, that would look good on a rocket.)

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In other news, the CTI Pro 75 M1830 C-Star motor I'll be using for the Level 4 attempt arrived in the mail this afternoon! I'll be using an AeroPack adapter to adapt it to the 98mm motor mount. I've borrowed a 4-grain case from a fellow club member for this flight.

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It took a few attempts to print it (kept getting a large and sudden layer shift with my printer 15+ hours in; eventually determined it was an overheating issue on the control board and made some upgrades/modifications to the printer to improve the cooling which seems to have fixed it).

Anyway, here are some pics with an RRC3 and RRC2 mounted. I think this is the configuration I will go with for the Level 4 flight as I have much more experience using the MissileWorks altimeters than I do the Altus Metrum EasyMini. Next thing will be to do the wiring. Black was not my first choice for the colour of the sled although it will match the paint scheme. The filament I'd ordered for this got lost in the mail for a while, though it eventually turned up (as this print was nearing completion in fact :rolleyes:).

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Speaking of paint, here is the paint scheme I ultimately decided to go with as depicted with the help of OpenRocket Photo Studio. Actually the rocket itself is already painted in real life, but I'll save the final reveal for a bit later on once I get some nice pics... :)
In other news, the CTI Pro 75 M1830 C-Star motor I'll be using for the Level 4 attempt arrived in the mail this afternoon! I'll be using an AeroPack adapter to adapt it to the 98mm motor mount. I've borrowed a 4-grain case from a fellow club member for this flight.

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That turned out great, thanks for the photos. :goodjob:
 
Here she is with paint and vinyl!

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Chronologically, this was done before painting.

I epoxied the nosecone bulkhead with tracker mount to the nosecone coupler. I made sure to have a generous fillet of epoxy on both sides.
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To secure the upper airframe to the avionics bay and the nosecone coupler to the NC itself, I used five 8-32 machine screws and PEM nuts (same ones I used for the AeroPack retainer). 3 would have been sufficient I think, but 5 equally spaced around the body tube looks more aesthetic. The installation procedure consists of drilling a hole for the machine screw through the airframe and coupler together and then removing the coupler and enlarging the hole in it to the correct size for the PEM nut. I then put the PEM nut in place and used a spare screw and a washer to pull the PEM nut into the hole in the coupler by torquing the screw.

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For paint I used Rustoleum 2X Painters Touch gloss white and gloss black. Before painting, I went over the fin fillets with some Bondo spot putty to fill any imperfections (forgot to take pictures). After spraying on the white, I let it dry for a couple days and then masked off the white areas of the booster in preparation for the black.

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After letting the black dry for a few days, I applied the vinyl name decal which was kindly made for me by a friend and fellow club member (who is also working on her L4. If she succeeds, she will be the first woman in Canada to become L4 certified. Both of our flights are planned for the same weekend in July).

The name Cosmic Kiss was inspired by ESA astronaut Matthias Maurer’s recent mission (named Cosmic Kiss) to the International Space Station as part of SpaceX Crew-3. As he put it, the name Cosmic Kiss is a declaration of love for space. Seems appropriate for a level 4 rocket built by a guy who has loved rockets and space since he was a little kid :)

Painting a rocket of this size was definitely a learning experience for me. I discovered that you will need more paint than you think. It is also quite hard to get an even coat down. In my case there are a few spots where the white paint is a little bit thin and which I only noticed after I'd already applied the black. Overall though, I am quite pleased with how the paint turned out but it definitely won't win any awards...
 
Getting near the finish line. I got the avionics bay wired up using 22awg silicone wire. I used JST-PH 2.0 wire connectors to make one of the av-bay lids easily removable.
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I also received and installed a Runcam2 camera shroud from Additive Aerospace to hopefully capture some 4K onboard footage during the flight:
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What do people recommend for shear pins? My current calculations suggest three 4-40 pins for the nose and three 2-56 pins for the booster should be adequate, but I'd like to hear what others have used on similar rockets.
 
I just flew my L3 with an Ultimate Wildman this past weekend. I used 2 x 2-56 pins for the booster, 4 x 4-40 for the nosecone.
My shakedown flight went perfectly. The first attempt, I blew the main at apogee. Made some changes, and the second attempt worked.
 
I just flew my L3 with an Ultimate Wildman this past weekend. I used 2 x 2-56 pins for the booster, 4 x 4-40 for the nosecone.
My shakedown flight went perfectly. The first attempt, I blew the main at apogee. Made some changes, and the second attempt worked.
Would love to see some pics!
 
For all my Wildman 6" Ultimate rockets, I only use 4-40 pins in the nosecone and no pins in the booster. These are streamlined birds, very unlikely to have drag separation. No harm in putting pins in the booster, but you definitely do not need pins larger than 2-56. I have hit my DS Ultimate with an AT M4500 and that Super Thunder load packs a wallop. I have RunCams pointed fore and aft and always watch the videos carefully to check for flight discrepancies. So far, there has been no hint of drag separation.
 
Three 4-40 for the nose is a good idea. I stayed with 4-40 on the booster end, but your suggestion is probably adequate.
I use two 4-40 on the nose and booster section. 2-56 failed me once during a high thrust launch. I’d stick with 4-40 all around.
 
So time to give an update to this thread. If all goes well I'm hoping to launch it this weekend (but that is a little bit up in the air at the moment for various reasons).

To finish up the build, I drilled holes for three 4-40 shear pins to retain the nose, and two for the booster. I chose to go with 3 and 2 for the nose and booster respectively as a compromise between having enough holding power to handle a nominal flight profile, while favouring an early separation (rather than no separation at all) in the event of an off-nominal flight profile and/or weak ejection charge. Using a fewer number of pins also means that smaller BP deployment charges are needed which will help to minimize the forces exerted on the structure of the rocket. According to various sources I found, a single 4-40 shear pin is capable of retaining between 40-55 lbs of load force before shearing. For the nosecone this means that it should take between 120-165 lbs of force to break the three shear pins (and for the booster 80-110 lbs of force). The mass of the nosecone is 5.2 lbs meaning that at minimum it would take 23G of acceleration to break the three shear pins. According to OpenRocket, the maximum acceleration immediately after motor burnout is -2.5G. In reality the drag separation force will be at most maybe 2/3 of this, if even. The other factor that needs to be considered is the greater atmospheric pressure inside the rocket compared to the atmospheric pressure at altitude forcing the rocket sections to separate. To help minimize this effect, two 1/8” pressure relief holes were drilled into the side of the main parachute compartment, and a single 3/16” hole in the booster.

At this point the rocket is now complete and ready to fly, although I still need to ground test my charges. Final built weight is almost exactly 37 lbs according to my bathroom scale. My initial estimate was 35 lbs so not too bad overall - for me anyway :)

I took the rocket into the back yard and laid out the recovery system to get a sense of it. I wrapped the shock cords with foam copper pipe insulation at the points where they will contact the edge of the body tubes to protect them from getting damaged by the tube edges. I also used sandpaper to knock down the sharp edges of the body tubes.
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Here is a plot of the flight profile simulated with the latest beta version of OpenRocket:
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Motor: CTI Pro 75 4-Grain 5604M1830-P C-Star
Estimated dry weight: 37 lbs
Estimated launch weight: 47 lbs
Thrust to weight: 8.7:1
Velocity off rail: 20.4 m/s (using 8 ft rail — extendable to 12 ft if needed)
Apogee: 7216 ft (time to apogee 21 s)
Max velocity: 234 m/s (Mach 0.69)
Max acceleration: 9.47 G
Ground hit velocity: 4.7 m/s
 
Really nice-looking build! Well thought out! On my next larger build I think I'll try that fin pocket design. Really looks like it should add a lot of strength and makes it a much cleaner build than doing regular internal fillets.
 
Brought her out to the launch site and did some ground tests yesterday. So far it has been a wet and windy summer, and this launch weekend is proving to be no exception :mad:
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I tested 5g of FFFG for both the main and drogue. 5g seems about right for the nose, and a tad excessive for the booster, but I plan to stick with it per the advice of my Level 4 Certification Committee members. For future flights I will likely cut down the drogue charge to 4.5 or 4g. I was a bit concerned about the 3D printed charge wells holding up, but they performed beautifully!

Main:
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Drogue:
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Unfortunately the weather today isn't conducive for launching. Tomorrow is also looking iffy, so at the moment it seems likely this will only fly at the next opportunity in September. (And there is also the fact that some of my support crew likely can't make it to this launch due to recovering from Covid).

I'm hoping to at least fly my Featherweight GPS tracker in my Wildman Shape Shifter Jr this weekend to test it out and get some experience with using it before sending it up on my L4 flight.

Not my photo, but here is a pretty cool pic of the launch pad that Cosmic Kiss will be launching from! :cool:
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Well shortly after my last post on Saturday the weather started to take an abrupt turn for the better. I headed out the launch site in the early afternoon. By evening the sky had cleared and the winds were calm enough for me to test-fly my Featherweight GPS tracker in my Shape Shifter Jr on a CTI I345 WT to 2712'. It was a perfect flight and the Tracker worked flawlessly (the spoken telemetry feature is pretty cool), giving me the confidence to use it on my Level 4 flight.

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A fellow club member who knows someone with access to detailed wind forecasts reported that they were predicting calm winds and relatively clear sky for the launch site on Sunday morning. Up until this point, I'd pretty much decided to scrub the L4 flight until September, but with the successful test of the tracker and new forecast, I revised my decision and decided to aim to fly the Level 4 flight first thing on Sunday morning.

After getting home (the launch site is only about an hour drive from my house) I stayed up a bit too late on Saturday getting things prepped as best I could. I folded up the main Parachute in my kitchen (had to banish my cats to the basement :rolleyes:) and measured out and prepped all the BP charges so that I could just connect them to the bulkhead terminals the next day. I also made sure that all my batteries were fully charged up.

The forecast for Sunday morning proved to be correct. I left for the launch site around 6:30am. The sky was blue, and there was barely a breath of wind in the air when I arrived. I immediately got to work prepping the rocket and assembling the motor under the supervision of my two Level 4 committee members.
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It was then time to carry it down to and load it on the pad.
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The rocket was then raised to vertical and the electronics and onboard camera were armed for flight.
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