10" diameter JayHawk

[SMR]

I noticed you used an Aerotech case for the CTI load. I mention that because I am thinking about what to use for my Level 3 cert flight. I thought about buying a Aerotech case which will allow me to choose either an Aerotech or CTI load.

I started with Aerotech hardware, so I was more familiar with it, and I like White Lightning propellant. My original plan was to fly the Jayhawk on an M1939-W (98/10240). I later redesigned the wing to fit a longer motor mount to add the N2000-W (98/15360) to my list, but with the nose weight I needed for stability, I blew right past the weight that either of those motors would have been able to handle. Cesaroni has some great motors, and thankfully has been getting them certified in RMS hardware, which give us options. I have recently acquired some CTI hardware in 29mm, 38mm, and 54mm, and have no complaints there, either. I think you'll be happy whichever way you choose to go. More a function of what your motor vendor carries. Wildman is ours, and he carries a good inventory of both. Good luck with your L3 cert flight. Will we get to see the build on TRF?

 

[n3tjm]

Already got a rocket for my L3, with one attempt under my belt. Had electronics issues which resulted in the p-chute charges never going off. Right now I estimate $300 to get the rocket repaired and another $300 for a new motor, and $300 if I decided to buy the motor hardware. Right now I am paying off debt so I want to wait till that's taken care of before I spend that kind of money again. Will be about 4 years before its paid off. But that does not stop me from planning and dreaming

https://www.youtube.com/watch?v=_7LxxKfKppE

 

[SMR]

Still collating a comprehensive flight report. Lots of data to sift through. Though we did not get any realtime information from the XBee transmitter in flight, I have recovered the stored data from the 3 onboard altimeters. In the meantime, here is a link to the video of the flight, taken by friend and fellow WOOSH member Marc S. (with really steady hands!)

ground video

 

[SMR]

Final test flight report - 10" diameter Jayhawk, MidWest Power 8, 30 October 2010.

It took a while to sort throughout the data, videos, and photos, and then to write this up, so my apologies for the lengthy delay. This is the final flight test report for the 10" Jayhawk from Midwest Power 8, on 30 Oct 2010. I had 9 objectives for this flight, so I will break down the flight into appropriate sections.

(a) Liftoff (taking the thrust kick off the pad, NO cato)
(b) Stability (triple check this)
(c) Staying together (no flutter / shred)
(d) Apogee (full drogue, NO zipper)
(e) Clean main deployment (no interference, no failure of attachments)
(f) Soft landing (in the clear, surviving ground impact)
(g) Evaluating the range of the XBee transmitter and its ability to transmit real-time altitude data
(h) Comparing the postflight data from the transmitting altimeter with the data from the recovery system altimeters, to possibly separate their functions
(i) Evaluate externally mounted video cameras on removable / interchangeable accessory pylons​

Preflight

I would have preferred to have a majority of the preflight setup done before arriving on the range, but with the cold overnight temperatures, the Jayhawk being too big and heavy to bring inside, and the altimeter bay buried inside the rocket when assembled, that was not an option. Keeping the altimeter batteries warm necessitated leaving the avionics sleds out of the rocket until the morning of the launch. I arrived at the prep area early Saturday morning. Mark from StickerShock23 brought the few decals I hadn't put on yet, and they were all attached by about 10:00 AM. Members of WOOSH were gathering throughout the morning, and there was never a shortage of help. Thank you! The avionics sleds and tether were installed, the upper body tube bolted on, three 192" main parachutes (pre-packed in deployment bags), 120" drogue chute, 24" pilot chute, and all shock cords were installed by about 2:00. There was substantial wind in the morning, but it appeared to get better in the early afternoon, so the decision was a go for launch at mid-afternoon. Seven of us carried the 160 pound rocket on a "stretcher" to the RSO table, and then out to the away pad. We carefully slid the rocket onto the 1515 launch rail / triangular truss tower, and winched it to vertical. The LCO read a summary of the rocket's statistics and a brief dedication to Erik Gates, and the button was pushed.

(a) Liftoff (taking the thrust kick off the pad, NO cato) - successful

I originally intended the rocket to fly on the M1949-W, with a backup of the N2000-W. Early in the build, it appeared the weight would be over my target, and team member Manny suggested the Cesaroni N3180 Red Lightning (certified in Aerotech hardware) might be an option. I also added a few features into the rocket during the build to help transfer thrust from the aft end of the tailcone to the more massive components (main wing and nose cone). This was my first "N" motor and, never having built a Cesaroni motor in Aerotech hardware, I had some concerns about the possibility of a cato. The N3180 uses the larger XL-style nozzle, with a longer shoulder. In RMS hardware, this requires a different rear closure, specifically made by Cesaroni. The aft O-ring fits into a slot in the side of the nozzle, and it appears to not get compressed as the aft closure tightens. Fortunately, I took an early delivery of the Cesaroni motor and built it prior to launch day, and I was able to spend some time on the phone with Jeroen at CTI, who walked me through the motor assembly. Even then, I pretty much held my breath until MECO at 4.5 seconds. At launch, she rose majestically from the pad under the full roar of the Cesaroni N3180, took the full thrust kick off the pad, and had no cato.

(b) Stability (triple check this) - successful

This is my 14th Jayhawk. Three of them (Polecat 4.0" and 5.5", MadCow 2.6") were kits, the others were scratchbuilt / odd-rocs. The kits all required the use of nose weight to keep the Cg forward of approximately the 60% point, which is where I have always put it on my scratch-builts as well. They, however, were all light enough to swing test to verify stability prior to flight. On this Jayhawk, I had approximated the Cp by halving the wing size and attaching four of them, with half of the winglet attached to each wing tip, a technique taken from the Gates Brothers full-scale Jayhawk build a decade ago. I have been using Rocksim for some bigger 3FNC projects, but wasn't aware of all the features added to it since then until they were pointed out to me by redsox15. (Thanks, Matt!). Rocksim is a great program, easy to learn and versatile. I was able to add winglets perpendicular to the tips of the main wings, and attach canards to the nose cone. The Cg came in at 93.2" aft of nose tip, and with a 25 pound slurry of #4 lead shot and epoxy added to the nose cone, the Cg was brought forward to 82.9", a 1.0 caliber stability margin. She came off the rail perfectly straight. She followed that up with the Jayhawk's characteristic half roll and arced into the crosswind following motor burnout. She was stable.

(c) Staying together (no flutter / shred) - successful

I had a lot of help with this. (Thanks, Mark and Tim!) Early in the build thread, there was some discussion about the possibility of wing flutter. I built three different wings before settling on the one that flew. The first wing was a 3/4" plywood frame with a 1/16" G-10 skin. It was rejected early in the build, as I was able to delaminate the G-10 by induced wing bending moments. (It also could only fit the 98/10240 casing and I was already starting to feel the need for more AP.) The second wing was 3/4" plywood with cabinet plywood skin, which adhered better to the plywood frame, and featured a redesigned motor mount cutout to fit the 98/15360 casing. The third wing was built from 1/2" Baltic Birch plywood (to save weight), using the same cabinet plywood skin and 98/15360 motor tube cutout. A layer of carbon fiber cloth and a 2-ply layer of fiberglass cloth (with the weave rotated 45°) was added, which wrapped around the G-10 motor tube, reinforcing the wing-motor tube joint. The long tang made the wing structure stiffer, but the long slot would weaken the body tube. Internal fillets and fiberglass cloth were added to compensate for that. Finally, all centering rings were bonded in position and the tailcone installed, foamed internally, and glassed externally. There remained the possibility for one flutter mode, the one with the tail flipping up and down like the tail of a dolphin, or a butterfly kick, but at this weight and corresponding slow speed, it did not manifest itself. Postflight review of video from the aft-facing GearCam shows the wing stiff as a board throughout the flight. She held together and did not flutter.

(d) Apogee (full drogue, NO zipper) - partial success / partial failure

Well, I had no zipper, and briefly had a full drogue. However, my decision to launch on a windy day came back to bite me. Averaging the two main altimeters, the maximum altitude of 3,381.5' occurred at 17.7 seconds. Postflight review of video from the forward-facing GearCam shows the nose cone ejected cleanly away, exactly at apogee. Due to the crosswind, however, the Jayhawk was angled significantly into the wind and was still traveling at a pretty good speed when the drogue caught air. The 24" Giant Leap TAC-drogue pilot chute was the first to sample the air, opened perfectly and remained so throughout the remainder of the recovery. On first inflation, it fulfilled 100% of its design function, pulling the Kevlar deployment bag off of the 120" Spherachute drogue. The opening shock of the large drogue exceeded the structural integrity of the stitching along several seams, and it immediately shredded. Drag from the flapping nylon, combined with the best effort of the still viable 24" pilot chute, limited the rocket to a descent rate of approximately 118.3 feet per second until ground contact at 48 seconds.

The forward facing video also showed the forward tube opening was zipper-free, at least on that side of the rocket. The body did a few aerobatic gyrations before catching the shock cord on the winglet on the aft-facing camera side of the rocket, which held it in a nose-down attitude for the duration of the flight. The shock cord hit the side of the GearCam at 15:46:52 camera time (43 seconds into the edited video), pushing on it continuously for 15 seconds and breaking it off the pylon at 15:47:07 camera time (58 seconds into the video). The camera then tumbled alongside the rocket, still shooting video, alternating footage of the rocket and the countryside. One frame showed the forward tube opening with the shock cord. The Kevlar band had held firm and there was no zipper.

As rockets get larger, the need to understand how to reduce loads becomes more critical. -Kevin

 

[SMR]

e) Clean main deployment (no interference, no failure of attachments) - failure

The tether functioned perfectly and all attachment points stayed connected. When I pulled on the drogue shock cord, the main deployment bags slid easily out of the forward body tube, and when I pulled on the main recovery harness, the main parachutes slid easily out of their respective bags. Two things combined to stop that from happening in flight. The first and most obvious was the failure of the drogue, discussed above. The second was the orientation of the rocket at tether release altitude (1,100') through ground contact. Video from the aft-facing GearCam shows the body flipped back and forth a few times, hitting the shock cord on the outside of the winglet at 38 seconds, and again on the inside of the winglet at 43 seconds. The second contact snagged the shock cord. With the body inverted and oriented slightly past vertical, a three-way combination of unrelated factors found equilibrium. With the nose cone off, the remainder of the rocket is tail heavy. Forces from the heavy tail leaning against the shock cord, combined with the residual drag from the pilot and drogue parachutes, and airflow over the wing, balanced each other perfectly and held this completely unforeseen and hauntingly stable nose-down attitude for the remainder of the flight. My vantage point was very close to where Marc shot the ground video. I could see the drogue was in trouble early in the recovery, but held hope there would be enough drag to give the mains a chance at 1,100'. That chance was eliminated when it stayed nose down.

(f) Soft landing (in the clear, surviving ground impact) - partial success / partial failure

The orientation of the rocket brings up a "what if" scenario, with three possible outcomes. In the first, what we experienced, the rocket holds the nose down attitude and the outcome is known. In the second, in a perfect world, the rocket manages to correct its orientation and the mains deploy as planned. In the third, the rocket is again released from the nose-down attitude, but there is NOT enough drag to deploy the mains. That scenario would have been the worst, as coming in tail-end first or tumbling would clearly have destroyed the rocket. I probably had the luckiest recovery possible for a 100+ pound rocket with no main deployment and a shredded drogue. If you recall my list of favorite landing surfaces (post 174), a freshly plowed field was ranked 4th of 17 possibilities. Under the limited drag of the world's largest streamer, the rocket came in at 118.3 ft/sec (81 mph), open payload bay first, into a freshly plowed field of soft, black topsoil. The rocket impacted near vertical and intact, yet, like the Titanic, the two major sections were found in separate locations. The forward tube absorbed a portion of the energy destructively, like dedicated crumple zones in a Volvo, and the remaining energy in compression, like a big spring. The three main parachutes, in Kevlar deployment bags, possibly contributed a fair share here as well. Not allowed to function as designed, they served in a secondary capacity as a really big pillow. The motor section was tossed back into the air in line with the angle of impact, and landed about 10 feet away, unscathed. The nose cone landed next, sticking the landing with no tumble, and other than light scratches, also unscathed.

Getting everything home and cleaned up, I was able to do a proper inspection of actual damage. The forward body tube, as expected, was totally destroyed. A portion of the tube was still attached to the avionics bay / body joint, which is part of the motor section / fin can, and it was removed to inspect the coupler. The twelve tee nuts that held the two body sections together were originally epoxied inside the coupler with JB Weld. Three of these tee nuts had cracked JB Weld, indicating they took some stress. The coupler itself, with two layers of carbon fiber, was in perfect condition. One of the screws holding the three 1500 series rail buttons on the rocket exterior was bent slightly, probably as a result of going past the not-quite-perfectly-lined-up rail joint on launch. I also borescoped the motor tube, as I felt any damage to the internal structure of the rocket would manifest itself in cracks in the G-10, or the fillets of the wing tang, visible through the translucent G-10. There was nothing, the only damage to the lower body was a scratch on one winglet, which we made putting it ON the pad.

The majority of the rocket survived the event. I have extra 10" Polecat tubing, so the repair / replacement of the forward tube will be relatively easy. I need to drill a few holes and add some paint, but she will be ready to fly again at LDRS 30 in Sep 2011. With a heavier drogue and in lighter wind.

 

[SMR]

(g) evaluating the range of the XBee transmitter and its ability to transmit real-time altitude data - failure
(h) comparing the postflight data from between the transmitting altimeter with the data from the recovery system altimeters, to possibly separate their functions - successful

These were secondary goals of the flight. Basically, it used the MAWD's ability to send data out the serial port to an XBee radio, which would transmit the data to a ground station during flight for display on an LCD screen. A dedicated MAWD altimeter and an XBee transmitter were flown in a secondary avionics bay built into the piston / plug thing forward of the main parachute deployment bags. This was also a test of that configuration. The configuration was what actually failed. The main avionics bay was reinforced with carbon fiber, creating a grounding plane around it and eliminating the possibility of using a transmitter within it. I had the option of putting the transmitter into the nose cone or the piston / plug thing. (I never did come up with a good name for that part.) I wasn't sure about the quality of the sampled air at the nose cone location as the air would be disturbed by the curvature, so the piston location won by default. Two static ports were drilled through the upper body tube to align with openings in the piston, and I built two unique avionics sleds for the piston internal bay. One sled was a 102dB piezo siren, the other the MAWD / XBee combination. The sleds each had a 4PDT push-on push-off (POPO) switch installed, which would allow the electronics to be armed with a dowel. Sharpie marks inside the body ensured proper alignment of the plug's static ports with those in the upper body tube during pre-flight assembly. Unfortunately, during the thousand foot march to the away cell, the alignment of static ports was lost. To arm the forward bay electronics once the rocket was vertical on the pad, I had to pry the inner tube against the body tube, using a screwdriver as a lever, to realign the holes. In a classic example of Murphy's Law, the first POPO switch I activated was the siren, which prevented me from hearing the self-test beeps of the MAWD when I activated that switch. Realizing that after-the-fact, I then turned the siren back off, but I was unable to find the POPO switch on the altimeter side with my arming dowel. I believe I broke the switch free of its mooring during all the manipulation of the bay. Since there were no pyrotechnics attached to this MAWD, there were also no continuity beeps. The forward avionics were just along for the ride and not essential to the safety of the flight, so they were not a no-go item, and the decision was made to launch without knowing if the board was working or not. No real-time data was received during the flight, but post-flight analysis indicates the board was indeed working. The plug / piston thing was in the open front of the ill-fated forward payload tube, and it suffered a fatal blow on ground contact. The two bulkheads were intact, but the coupler tube that separated them was partially crunched. It was the first thing removed from the forward tube at ground zero, and my check of the two ejection charge canisters is visible in video from the forward facing GearCam starting at 1:28, with the nose cone in the background. Internally, the four 9V batteries were all broken, exposing their inner components. The XBee itself was jarred loose from its socket on the circuit board but otherwise undamaged. The MAWD appeared intact, but remained silent until power up with new batteries, where it beeped out 20,000', which is a default report following power interruption (a feature added in firmware revision 1.20). Data from it was downloaded and compared to the main altimeters. Ascent data correlates well, with an apogee of 3,327' (vs 3,381') occurring at 17.5 seconds (vs 17.7 seconds). Post-apogee data does not correlate at all. The altimeter shows an immediate drop to 2,645' at 17.55 seconds, followed by a linear climb to 8,368' at 61.15 seconds. It "hovered" there until 66.20 seconds, followed by a straight-line and almost immediate drop to ground level at 67.35 seconds. (The main altimeters showed it on the ground at 47.95 seconds.) The post-apogee data indicates that the static ports once again lost their alignment (likely), and the altimeter may have suffered some damage and/or corrupted data from the apogee event or by deceleration forces on ground contact.

The forward avionics bay / piston / plug thing was intended primarily to reduce the volume to be pressurized to separate the nose cone at apogee. This required wires from the main avionics bay to BP charges above the piston, through the main parachute bay. If the altimeter in the piston reported altitudes aligned with the working altimeters in the main bay, these wires could be eliminated. The forward altimeters would then be used to fire the apogee charges, and the main bay altimeters would fire the tether charges for main deployment. It appears from the data that the forward altimeter functioned normally and it would be possible to use this setup for the apogee event. However, the static port alignment issue would reduce the reliability of that option below the threshold where I would ever do it without backup. The good news is that wires from the main avionics bay, secured with metal tape alongside the main parachutes and equipped with break-aways at the piston, was easy to set-up and reliable.

(i) Evaluate externally mounted video cameras on removable / interchangeable accessory pylons - successful

This was a huge success. I am now a big fan of the Booster Vision GearCam. The pylon attachments were solid and sturdy. They allowed me to attach the Jayhawk antenna array for static display and photo ops, and quick-change them to externally-mounted video cameras for flight. The aft-facing camera pylon took a beating from the shock cord for a majority of the recovery, and survived without damage. The aft-facing GearCam itself was pushed by the shock cord for a full 15 seconds before breaking one side of its base. It then free-fell for over a thousand feet, taking usable pictures the entire way. It was found 30' from the rocket. (Thanks, John!) Both GearCams took great video, were fun to watch, and provided much useful information about the flight, documenting both good (wings flutter-free, nose cone ejection at apogee, body tube zipper-free) and bad (drogue shred and shock cord capture). I'll be flying GearCams in this configuration again!

SUMMARY

Lessons learned… Everything functioned as designed. All charges fired, the nose cone separated cleanly at apogee, the pilot chute pulled the deployment bag off the drogue and it inflated. The failure of the stitching of the drogue parachute contributed to the crash, but was not the cause. The cause was, in all honesty, the "go" decision. There had been many successful flights prior to mine, but in the existing wind, the Jayhawk's larger wings led to a flatter flight profile. With the resultant higher speed at apogee and her higher mass comes an energy problem. Anytime a system's energy exceeds its binding energy, it will come apart. I asked too much of the drogue, and like the thoroughbred Ruffian, she gave it her best shot and broke down. Thanks for trying. For future reference, a smaller drogue may have been a better choice (the pilot chute did just fine), and less wind at launch is definitely a requirement.

This was a fun project to build and fly, and I would like to again express my gratitude to everyone involved with it… those who followed the build thread online, those who offered advice, and especially those who helped at the launch and recovery sites. I certainly couldn't have done this project without a lot of help, and the rocket community was there for me. It was a wonderful experience for my whole family. To them, I owe a lot of thank you's as well, for their patience and sacrifice in my preoccupation with getting this rocket built and flown. Even though the outcome was less than ideal, I feel like it was worth the time and effort. I learned a lot from both the build and the flight. We got great video and altimeter data, and were able to reconstruct the flight profile with relative certainty. My biggest goal (not landing in the parking lot) and secondary goal (being able to fly her again) were both fulfilled.

Once it's on the pad, it either works or it doesn't, and you have to deal with it either way. In rocketry, it's not the flights that matter, it's the people. In the end, the rockets are what draw us all together. -Kevin

Cheers. Sather

 

[RandyM]

You had considerably more success than failure.

It was a B..E..A.. utiful flight and I'm happy I got to see it fly!

Can't wait to see the repaired version fly at LDRS30!

 

[Wiley]

So, how much did this gorgeous thing weigh:y: (minus the motor)?

 

[SMR]

So, how much did this gorgeous thing weigh:y: (minus the motor)?

Fully loaded with parachutes and electronics, she came in at 133 pounds. Adding the 27 pound motor, launch weight was a whopping 160 pounds.

 

[SMR]

This thread was started on this forum right around when I did and I've followed it ever since....

It's also been WAY TOO interesting...we have to find some way to keep it alive after this weekend....

any ideas?

Thank you. Well, the summer flying season is winding down, and I finally have a little time to catch up with documenting the rebuild... in anticipation of the re-flight. I started with the only damage sustained by the motor section... inside the avionics bay. I cracked a few fillets of JB Weld holding the tee nuts that in turn hold the payload section in place. This was evidenced by mis-alignment of the 1/4"-20 bolts. I ground down the offending beads with a Dremel tool, and replaced the tee nuts with new ones. A little touch up paint on the winglet, scratched putting her ON the pad, and the motor section is complete.

 

[nh4clo4]

:wave:

 

[dixontj93060]

:wave:

Sather, are we going to see the Jayhawk fly at MWP9?

 

[RocketManDan]

This is my first really big scratch build, and first attempt to document it on the forum. I am building a 10" diameter JayHawk, (roughly 3/4 scale). Estimated launch weight approximately 100 pounds to fly on M1939-W, M2500-T, N2000-W, or N3300-R, depending on final weight. Launch is scheduled for late October at Mid West Power 2010. Special thanks to Andy Woerner for the concept, Jack Garibaldi and Polecat Aerospace for core components, and to Gates Brothers Rocketry for build tips. (First launch is for you, Erik.)

View attachment 16435

Really big? Really? Yeah I would think so...its a monster build! Nice job!

 

[UPscaler]

Thank you. Well, the summer flying season is winding down, and I finally have a little time to catch up with documenting the rebuild... in anticipation of the re-flight. I started with the only damage sustained by the motor section... inside the avionics bay. I cracked a few fillets of JB Weld holding the tee nuts that in turn hold the payload section in place. This was evidenced by mis-alignment of the 1/4"-20 bolts. I ground down the offending beads with a Dremel tool, and replaced the tee nuts with new ones. A little touch up paint on the winglet, scratched putting her ON the pad, and the motor section is complete.

Awesome! Wicked rocket man...I hope my dad and I can do something big like this eventually!

I've bolded something in that above post...

Wow, Braden, I didn't see your previous attempt at this, or I would have sent you a pile from last summer. (upscale Death Star, etc...). So, I'll put a box in the corner of the basement for you, of current / future projects gone bad. Of course, MY goal would be to keep YOUR box empty. We'll see how I do. Cheers, Sather

Ya got anything for me? :wink:

I guess I should say, "I hope not" :tongue:


come back to argonia next year, I want to see this thing fly!



Braden

 

[SMR]

Awesome! Wicked rocket man...I hope my dad and I can do something big like this eventually!

I've bolded something in that above post...

Wow, Braden, I didn't see your previous attempt at this, or I would have sent you a pile from last summer. (upscale Death Star, etc...). So, I'll put a box in the corner of the basement for you, of current / future projects gone bad. Of course, MY goal would be to keep YOUR box empty. We'll see how I do. Cheers, Sather

Ya got anything for me? :wink:

I guess I should say, "I hope not" :tongue:

come back to argonia next year, I want to see this thing fly!

Braden

I will definitely be coming back to Argonia. LDRS XXX was a very well run launch on a great flying field. Probably enough so that I will finally get around to joining Tripoli. (As a NAR-only guy, I could only fly on Friday thru Sunday. Friday was windy, Saturday was great, and Sunday was windy again. To make the drive, it would definitely make more sense to be able to fly all 6 days.)

And, nope, I haven't forgotten about my promise. (Even though you are, essentially, rooting against me. But, you were one of the first to support me when this build began - so I think of it as a return on your investment.) Your box still sits in the corner of my workshop. Empty! So, either I'm not flying enough or I've just had a lucky year - No hull losses for me. The only damage my fleet has sustained since setting out your box have been (a) the legs of my lander, and (b) a cracked winglet on the JayCoke Zero, both easily repairable (replace-able) components. Interestingly enough, both were lightened plywood, which splintered adjacent to my lightening holes, and I just finished commenting in bjphoenix's plywood discussion thread...

(https://www.rocketryforum.com/showthread.php?t=27755).​

Sounds good to me, sorta, I guess I'd have to hope for the demise of your rockets for them to be sent to me.

no one likes to see civilian casualties :wink:

Braden

The Jayhawk actually made the trip to LDRS XXX, but I only had one motor option available (on Sat), and I previously had learned my lesson about flying her in stiff winds (Fri and Sun). So yes, Tim, the plan is to have her fly at MWP. I'll have an M4770 (Vmax) and an M3400 (White Thunder) to choose from. Hopefully, the wind cooperates.

 

[SMR]

Really big? Really? Yeah I would think so...its a monster build! Nice job!

Thanks. I definitely learned a lot from the build, and I had tons of help from my local club as well as members of TRF. It is also interesting to see how far OFF I was on my original weight estimate. All the little things that get added as you go, i.e. all-thread, doubled-up rings, glass, etc., really add up in the end. The true craftsman among us are much better at building light.

Like everything in rocketry, there are compromises. The trade-off is not linear, though. If I was a better engineer, I could compute the actual numbers, but an example would be reducing the weight 35% and the strength by 10%. (And by reducing the weight, it also lowers the strength required.) My favorite saying from engineering is that anyone can build a bridge to support a given weight, but it takes an engineer to build a bridge that JUST BARELY supports a given weight. Of course, the weight savings in engineering is dollar driven, realized in reducing material costs.

 

[UPscaler]

Well.,
Congratulations on a successful season!


This project is one of the coolest things I've ever seen. Hope I can see it in person! Sometime.




Braden

 

[UPscaler]

Well.,
Congratulations on a successful season!


This project is one of the coolest things I've ever seen. Hope I can see it in person! Sometime.




Braden

 

[chadrog]

Sather, are we going to see the Jayhawk fly at MWP9?

I'm going to have to clear out the hard drive on my camera if I'm going to catch everything he has planned, 80 gig might not be enough!

 

[SMR]

With lead shot added for stability, the nose cone weighs 37.5 pounds. Landing in the freshly plowed field, she suffered only minor scratches on the tip and one canard. The vinyl decals from Stickershock23 were in perfect condition - I was able to mask and re-use them. (Thanks, Mark!!!) A little light sanding and touch up paint, and the nose cone is complete.

 

[SMR]

As anticipated the last window for painting before MWP opened this morning. Calm winds and highs near 60. Hope this holds out through Sunday evening--maybe even Monday!

Wow, you called that correctly. Got in a good day of painting today. Thanks for the heads up.

T minus 7 days

 

[UPscaler]

With lead shot added for stability, the nose cone weighs 37.5 pounds. Landing in the freshly plowed field, she suffered only minor scratches on the tip and one canard. The vinyl decals from Stickershock23 were in perfect condition - I was able to mask and re-use them. (Thanks, Mark!!!) A little light sanding and touch up paint, and the nose cone is complete.

looks excellent! I love Mark's Decals!



What are you flying it on?


Braden

 

[SMR]

looks excellent! I love Mark's Decals!

What are you flying it on?

Braden

I do, too. Mark also did the full body wrap on my JayCoke Zero recycling bottle. It landed in a tree, getting caught about 8' up. I pulled it down by yanking on the shock cord, dragging the bottle across the branches. The decal still looks perfect!

I prefer white motors*, so I am hoping to fly the Jayhawk on a Cesaroni M3400 White Thunder in dual deploy mode (with a Defy Gravity Tether). My backup motor is the M4770 Vmax, just to get it in the air. I'll throw the laundry out at apogee with that motor, since it won't get much higher than where the mains would be out in a dual deployment.

(* My original hope when starting this was to use either AeroTech M1939-W or N2000-W motors. When the weight got too much for those, my only AT option was Blue Thunder. Bzzzzzzt! Hence, the switch to CTI.)

 

[SMR]

The original payload tube was imbedded about a foot into the ground. It absorbed essentially all of the energy. Sacrificially. Unrepairable. But, fortunately, easily replaceable.

The original was a pre-glassed 10" tube from Polecat Aerospace, which come 46" in length. Since I add a heavier glass anyway, Jack Garibaldi at Whats Up Hobbies (Polecat) was kind enough to send me some raw tubing in the full 48" length. This made it easier to attach the anti-zipper band at the top. The extra 2" in length will help in stability as well as give a smidgeon more room for recovery gear.

I had tried a few different techniques with the original's anti-zipper band. The first was made from a nylon handcuff. I liked that it had rounded edges and was virtually indestructible, but it was pretty thick and difficult to fiberglass over smoothly. The second attempt, which was flown, was a strap of kevlar webbing. Thinner and literally bullet-proof, it was epoxied on after the tube was glassed, which made it more obvious. This time, I thought I would try and blend it in a little more. I used a length of galvanized pipe-hanging strap, which has the slight advantage of being thin. It also has holes along the length, which gave the JB weld plenty of places to reach the tube and help it adhere properly. The disadvantage is the metal edge does have the possibility to cut through the recovery system strap, so I'm going to add an anti-zipper ball to the strap to mitigate that. Using my extra 2" of room.

 

[SMR]

I added 2 wraps of 8 ounce glass to the new tube, over the anti-zipper band, which blended in nicely. The centering rings are just stuck in the tube temporarily, to hold it off the rotisserie, making the tube easier to turn and keeping the wet glass from fouling. Once the epoxy got tacky, I cut off the extra glass cloth on each end with an Xacto knife.

 

[SMR]

Glassing was followed by the inevitable filling and sanding and filling and sanding and filling and sanding. My primer was alternating coats of grey and white, which gave an indication against the blue Super Fil of where the high spots were, to help fill the low spots. I also added the 26" section of coupler to the tube as a sleeve, to help support the weight of the nose cone during boost. And a trial fit to mark the holes. Twelve 1/4"-20 bolts hold the payload tube to the motor section, and six more serve as static ports for the avionics bay. Since these holes already exist in the avionics bay coupler, careful measurement to ensure alignment was critical.

 

[SMR]

The attachment and vent holes were marked and drilled, and the tube once again trial fit in position to ensure they lined up. Since it fits correctly in only one position, not every 60°, I marked where the sides of the rocket (wings) are. This will be where the antenna / camera pylons will be on the payload tube. Just as with the original, the template was cut out and taped on the tube. I drilled right through it, and attached tee-nuts from the inside. With the added thickness of the coupler tube sleeve, I was able to use longer tee-nuts, giving me more thread length and not having to file the exterior edges down.

 

[SMR]

I love Mark's Decals!

Stickershock23 offers an awesome "crash replacement" warranty, which I unfortunately was able to take full advantage of. Also of interest, it appears that any area of the rocket that actually HAD Mark's high quality vinyl also suffered NO damage. They really are indestructible! The motor section of the rocket was unscathed, the nose cone decals survived, and the payload tube was only damaged at the top and bottom, areas that were essentially sticker-free. If I had tried to peel the stickers off the old payload tube, or if I was able to "splice in" tube sections only where needed, I wouldn't have needed replacements at all. Must be some sort of force-field in place.

Anyway, I sent Mark a list of the payload tube decals (circled in yellow in attachment #1) and he fixed me right up. Using the original tube as a template, it took only a few minutes to attach them, and the payload section is complete.

Note - attachment #2 is in the hallway of the Best Western in Wichita, KS, at LDRS XXX.

 

[chadrog]

Do you have a time estimate for the flight this weekend? I know you have an awful lot on your MWP9 agenda.

 

[SMR]

Do you have a time estimate for the flight this weekend? I know you have an awful lot on your MWP9 agenda.

Well, it's a function of the weather, winds, and my sanity. All else being equal, the plan right now is...

Friday - JayCoke Zero bottle, either L3150-Vmax or M3400-WT
Saturday - 6.0" Pandora*, N5800-C Star drag race at noon
Sunday - 10" Jayhawk. either M4770-Vmax or M3400-WT​

For a variety of reasons, I had to reschedule the encore flight of the 12" Modular Booster. I didn't get the lander's legs rebuilt in time, and I really didn't want to overdo myself and not be able to fully take in everyone else's flights. I'm doing a couple of certs, a shift as RSO, and the night launch, so one big launch a day will be just about right.

* - my Ultimate Wildman, appropriately named since I really shouldn't have opened the box.