Blackhawk 54mm on a Loki L1400 (Minimum Diameter)

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Hello everyone! I've been lurking around the forum for awhile, but I've never posted a build thread before - I thought I'd try it out and see what you guys think. I built a Wildman Blackhawk 54mm rocket and managed to squeeze in a Loki L1400. I'll just spam a bunch of pictures below and kind of describe things. I'm still pretty new to the hobby and I had alot of help/ learned alot during this process.

One of my goals for the project was to learn how to do a carbon fiber overwrap on the fins. David Kittell was my mentor here. He taught me the process and allowed me to use the materials/tools in his inventory. The image below describes the layering process we used:

WP_20141019_065.jpg

Having never done this before, I decided to first do a carbon fiber overwrap on my wildman junior, which I had launched many times before. The idea here was to allow me to learn the process and to be able to do a better job for round 2 on the Blackhawk 54. Below, you can see that we made a fin template and cut out all the necessary layers of material. This pink layer is the bleeder layer.

WP_20141019_004.jpg

Here, you see the "diaper" layer already cut out. This is a cotton layer that absorbs all of the excess epoxy as it is pulled out of the carbon fiber. The green plastic on the floor is the vacuum bag material about to be traced and cut out.

WP_20141019_011.jpg

Gus cuts out the carbon fiber layer. It's important to use a pizza cutter here, not scissors. The carbon fiber frays very easily.

WP_20141019_026.jpg

Gus applies the first layer of carbon fiber and liberally applies West Systems epoxy. It's important to saturate and work as much epoxy as possible into the fibers. The vacuum will pull out any excess epoxy. We used 2 layers of carbon fiber for the wildman junior.

WP_20141019_042.jpg

After the carbon fiber, we place the bleeder layers. These layers don't stick to the epoxy, yet have holes to allow excess epoxy to be pulled through into the diaper layer.

WP_20141019_049.jpg

We tape on the diaper layer and then tape up the vacuum bag. We use very nice sealing tape to seal the edges of the vacuum bag. We pulled vacuum for 48 hours.

WP_20141019_053.jpg

You can see how the excess expoy is being pulled through the bleeder layers holes and is being absorbed by the cotton diaper layer.

WP_20141019_055.jpg
 
build thread continued:

After having done a carbon fiber overwrap on the Wildman Junior, I was ready to start putting together the Blackhawk 54. As per instructions, I tacked the fins with 5 minute epoxy using the fin guide:

WP_20141025_003.jpg

I then gave a generous epoxy fillet to the fins with west systems epoxy mixed with colloidal silica expander.

WP_20141026_014.jpg

Here, you can see the fin templates. Note that there are 3 templates of varying size --> We applied 3 layers of carbon fiber. Each layer was 0.5 inches larger on each edge from the last.

WP_20141026_021.jpg

Once again, we trace and cut out all the appropriate layers. Here, you see the vacuum bag about to be traced and cut.

WP_20141026_025.jpg

Again, we pulled vacuum for 48 hours. After removing the vacuum bag, it's a bit tricky, but we removed all the cotton and bleeder layers. Some sanding work with a dremel and mouser yeilds the following product:

WP_20141030_001.jpg

Those curves :jaw:

WP_20141030_005.jpg

I would also like to mention that, as a final step, I went over the fins with a thin layer of west systems epoxy. I found that this gave the fins a bit of gloss and brought out the contrast in the carbon fiber.
 
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build thread continued:

I selected the Loki L1400 motor for the advertised quick burn time of 2.0 seconds. My goal with this build was to make as fast of a rocket as possible --> I was only going for speed. As such, I shopped around for the largest 54mm motor with as quick of a burn time as possible. I came across the new and shiny Loki 54mm 4000 N-s motor. I decided that my end-goal is to launch the Blackhawk airframe on this motor. However, I decided to start with the L1400 (2800 N-s) motor for my first attempt --> allow me to learn, make mistakes, and also launch in Indiana/Ohio due to altitude waiver restrictions.

And mistakes were indeed made. This was my first time purchasing a non-CTI motor of impulse J or less. As such, I had never assembled a motor before. For my first motor assembly attempt, I decided to try and follow instructions for epoxying the grains into the liner. The instructions directed me to stack the grains and then place scotch tape between the grains. Then, apply epoxy along the grain stack. (The purpose of the tape was to prevent epoxy from getting between the grains.) Unfortunately, the addition of tape made the grains too big to fit into the motor liner. I got 3 grains into the motor liner and everything got stuck. I ended up breaking open the motor liner in order to reacquire the grains.

I communicated this failure of mine to Loki rocketry. As it turns out, the L1400 does not require that the grains be epoxied into the case. (Something I misread in an email) Simply shoving the grains into the motor liner is all that was required. Nonetheless, Loki has modified the grain gluing instructions to prevent an idiot like me from messing this up again. Loki also sent me a free motor liner replacement. I'd really like to say thanks to Scott for making great products and for being very helpful over the phone for helping me to save the motor.

The image below shows the new motor liner and the condition of the grains after I freed them from the old motor liner.

WP_20141115_003.jpg

I tore off a layer of white paper from the 3 glued grains in order to make them smooth and even:

WP_20141115_004.jpg

Scott then directed me to place a layer of wide masking tape over the grains in order to replace the torn-off white paper. I did this and test-fitted the grains until the were nice and snug in the new liner.

WP_20141115_008.jpg
 
build thread continued:

I like to play around with electronics, so I had a bit of fun with the avionics bay. I used a Raven for handling deployment charges. However, I also added in some electronics for datalogging flight characteristics. The purple board is an ardupilot. This controller is normally used for controlling and flying hobby aircraft and quadcopters and such. It's a pretty nifty board because it has an embedded IMU and a high quality barometric pressure sensor onboard.

WP_20141116_002.jpg

At the top of the payload sled, we placed a high-quality GPS sensor. The ardupilot was responsible to taking data from the GPS and datalogging everything.

WP_20141116_003.jpg

It's also nifty to note that the sled was 3D printed with a Makerbot2. (Thanks to Purdue College of Technology 3D Printing Lab.) The other side of the sled housed the batteries. The Raven was powered by a Duracell 9v. The ardupilot was powered by 3 lithium Energizer AAA batteries. (The batteries were soldered into series.)
 
build thread continued:

We first tried to launch this at the 11/23 Indiana Rocketry launch. Unfortunately, the low and heavy cloud layer scrubbed the launch. As such, we tried again at the Ohio Aerospace launch on Black Saturday in South Charleston, Ohio. Despite fighting a cold, Gus woke up bright and early and drove out to the field from Indiana in order to help me prepare and launch the rocket. Here we are getting things ready in the bed of his truck:

WP_20141129_001.jpg

Getting her on the launch rail:

IMG_6685.jpg

For as long as we launch in the Midwest, we will have standoffs --> corn!

IMG_6687.jpg

One last picture and a kiss for good luck:

WP_20141129_002.jpg

She awakens:

wp_ss_20141129_0002.jpg

Aaaaaaand, she's gone

wp_ss_20141129_0001.jpg

Here is the video. The launch occurs at ~0:33 into the video. Apologies for the poor camera handling. I was holding it at chest level and following it with my body. (The battle between wanting to watch the rocket with my own eyes and wanting to be able to get a good video at the same time.)

[video=youtube_share;H_JTUkj514c]https://youtu.be/H_JTUkj514c[/video]
 
build thread continued:

We first tried to launch this at the 11/23 Indiana Rocketry launch. Unfortunately, the low and heavy cloud layer scrubbed the launch. As such, we tried again at the Ohio Aerospace launch on Black Saturday in South Charleston, Ohio. Despite fighting a cold, Gus woke up bright and early and drove out to the field from Indiana in order to help me prepare and launch the rocket. Here we are getting things ready in the bed of his truck:

View attachment 247992

Getting her on the launch rail:

View attachment 247994

For as long as we launch in the Midwest, we will have standoffs --> corn!

View attachment 247995

One last picture and a kiss for good luck:

View attachment 247996

She awakens:

View attachment 247997

Aaaaaaand, she's gone

View attachment 247998

Here is the video. The launch occurs at ~0:33 into the video. Apologies for the poor camera handling. I was holding it at chest level and following it with my body. (The battle between wanting to watch the rocket with my own eyes and wanting to be able to get a good video at the same time.)

[video=youtube_share;H_JTUkj514c]https://youtu.be/H_JTUkj514c[/video]

How high and at what speed?
 
build thread continued:

I am very happy to report that everything in the avionics bay worked PERFECTLY!!! As such, I managed to pull datasets off of both the Raven and the Ardupilot. I had 4 separate ways of determining altitude over time:

1) Integrating Raven axial accelerometer over time
2) Raven pressure altitude
3) Ardupilot pressure altitude
4) GPS altitude

alt2.png

As seen, we hit an apogee of approximately 17,600 feet ASL. This corresponds to approximately 16,600 feet AGL.

The pressure altitudes were both very similar. During motor burn, the pressure altitude is unreliable due to high acceleration and Mach. The accelerometer altitude seems to be the most reliable during motor burn and Mach.

The following plot shows the number of satellites visible to the GPS over the time of the launch:

sats.png

We can see that for most of the launch, 9 or so satellites were visible. This generates good GPS data. However, we loose a GPS lock during motor burn and high speed. The yellow bar in the altitude plot indicates the time period for which no satellites are visible. (No GPS lock.)

As seen in the altitude plot, as soon as the satellite lock is reacquired, the GPS data quickly begins to catch up. It takes some time for the GPS data to become accurate again as it is trying to figure out where it is.

mach2.png

Here is Mach speed over time up until apogee. Again, the yellow bar represents lack of GPS lock.

Lastly, I plotted the GPS data in 3D into Google Earth. Note that the data slightly before and after losing GPS lock is a bit wonky and unreliable.

google maps.png

map1.jpg

birds-eye view:

map2.jpg
 
build thread continued:

I am very happy to report that everything in the avionics bay worked PERFECTLY!!! As such, I managed to pull datasets off of both the Raven and the Ardupilot. I had 4 separate ways of determining altitude over time:

1) Integrating Raven axial accelerometer over time
2) Raven pressure altitude
3) Ardupilot pressure altitude
4) GPS altitude

View attachment 247999

As seen, we hit an apogee of approximately 17,600 feet ASL. This corresponds to approximately 16,600 feet AGL.

The pressure altitudes were both very similar. During motor burn, the pressure altitude is unreliable due to high acceleration and Mach. The accelerometer altitude seems to be the most reliable during motor burn and Mach.

The following plot shows the number of satellites visible to the GPS over the time of the launch:

View attachment 248000

We can see that for most of the launch, 9 or so satellites were visible. This generates good GPS data. However, we loose a GPS lock during motor burn and high speed. The yellow bar in the altitude plot indicates the time period for which no satellites are visible. (No GPS lock.)

As seen in the altitude plot, as soon as the satellite lock is reacquired, the GPS data quickly begins to catch up. It takes some time for the GPS data to become accurate again as it is trying to figure out where it is.

View attachment 248001

Here is Mach speed over time up until apogee. Again, the yellow bar represents lack of GPS lock.

Lastly, I plotted the GPS data in 3D into Google Earth. Note that the data slightly before and after losing GPS lock is a bit wonky and unreliable.

View attachment 248002

View attachment 248003

birds-eye view:

View attachment 248004


You really do find gold at the end of the rainbow!
 
build thread continued:

lastly, I would like to make some acknowledgements:

1) Gus Piepenburg --> Gus has been my rocketry mentor since the Purdue USLI days. I did the majority of rocket construction out of the bed of his pickup with his help. Can't say thanks enough Gus!!
2) Dave Kittell --> For teaching me how to perform a carbon fiber overwrap and for allowing me to use your materials/tools
3) Andrew Davis and Dahlon Lyles --> for helping me with the avionics payload. Andrew did the majority of the Ardupilot software programming. Dahlon was responsible for the majority of the 3d printing work.
4) Ohio Aerospace rocketry group --> for allowing me to launch and for calling in the required waiver extension
5) Loki Rocketry --> for making great products and for helping me to save the motor when I messed it up
 
Nicely done!

I though that it would go higher??
My 4" rocket weighs 26+ lbs on a full L / baby M does almost 15k


JD
 
Brent...That was a Rocking flight man! That Loki motor really shot that thing out of a cannon. Too bad about the booster but, we can build another one...Glad i could help out in anyway needed that day. Wait till you see what "Uncle Gus" is building on the Kitchen Table right now! :D
Call me if you want to put another bottom end together...;)
 
Well done - rocket and thread. I noticed that sled right away and thought, "oooh, what's that?". Cool that you designed/printed your own - looks like 3D printing is getting more and more "mainstream" all the time. Won't be long til it's common for everyday/regular people to have them, similar to how 2D/paper printers are.

One thing: I realize that I'm out west where there's lots of room in the world, but isn't that launch site a bit close to town? It seems to me from the google-earth pics that the rocket could have very easily landed right in the middle of little 'burg of South Charleston, no? Had something gone wrong and it came in ballistic, that could have been pretty nasty.

Otherwise, excellent work! Post more stuff here on the forum - don't just lurk, you've got cool stuff to share that we'd love to see and hear about.

s6
 
Congratulations on your build, flight, and recovery. What kind of weight did you get with or without motor?
 
Why did you leave the t2t under vacuum for 48hrs?

If I remember correctly, the full cure time for West Systems slow cure epoxy is 24 hours. I just doubled that for a margin of safety. You would probably be fine after the epoxy cure time
 
Congratulations on your build, flight, and recovery. What kind of weight did you get with or without motor?

It's silly to admit that despite all this work and the pretty plots, I forgot to weigh the thing. I haven't added an explanation for this in the build thread yet, but the booster shock cord snapped and I lost the booster. Only the forward airframe was recovered. If I get the booster back, I will be sure to weigh it.
 
Well done - rocket and thread. I noticed that sled right away and thought, "oooh, what's that?". Cool that you designed/printed your own - looks like 3D printing is getting more and more "mainstream" all the time. Won't be long til it's common for everyday/regular people to have them, similar to how 2D/paper printers are.

One thing: I realize that I'm out west where there's lots of room in the world, but isn't that launch site a bit close to town? It seems to me from the google-earth pics that the rocket could have very easily landed right in the middle of little 'burg of South Charleston, no? Had something gone wrong and it came in ballistic, that could have been pretty nasty.

Otherwise, excellent work! Post more stuff here on the forum - don't just lurk, you've got cool stuff to share that we'd love to see and hear about.

s6

Thank you! 3-d printing certainly simplified life. The other side of the sled had battery holsters for the 3AAAs and the 9v, so I didn't have to worry about the high-g loading tear the battery off. And it's difficult to see, but we were able to print mounting holes and standoffs for the electronics. We just print the holes small enough such that the can self-thread when you crank down on the screw. Works real well in the plastic. No nuts required.

I'll see if I can become a bit more active on this forum
 
It's silly to admit that despite all this work and the pretty plots, I forgot to weigh the thing. I haven't added an explanation for this in the build thread yet, but the booster shock cord snapped and I lost the booster. Only the forward airframe was recovered. If I get the booster back, I will be sure to weigh it.

I was just curious. I am getting into 54 mm min. diam. I lost a Space Cowboy going past 20 K. Would love to know my alt. and velocity. You did great. I am rebuilding by scratch. It could be a Black Hawk 54, Space Cowboy, or Madcow Tomach depending on which fins I put on. The Black Hawk 54 fins are awesome, but are pretty large. Just trying to fit everything together in terms of fins, weight, tip to tip. Your altitude and velocity are up there. Congratulations. You have entered a select group. Great place to be at. You can improve from there. Any thoughts on what happened to your shock cord? How long was it? What kind of kevlar etc.? I will recheck your thread. I think from your video I heard that you had 2 g of powder for charges. Seems like a lot. I had 0.8 g to 1 g in my Space Cowboy. Would have to check. I also did not understand in your video that you were waiting for main to come out to get a signal. The Black Hawk 54 was fiberglass, so should transmit. Any insight for us? I have CSI transmitter / receiver. I am contemplating gps, and what kind. Again, great job. 54 mm is not for the faint of heart. Good stuff. Hope that you find your booster.
 
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