The Bobs - Minimum Diameter N1000 Project

[UPscaler]

Hey everyone! I just wanted to do a bit of a build thread for this project that I just flew at BALLS.

The Bobs started life as a Wildman Falcon 98, but I shortened it to maximize performance. To ensure I had accurate measurements (under the assumption that the rear closure wouldn't thread entirely) I assembled the N1000 for the sake of taking measurements:


After that, I bolted the rocket's electronics bay assembly to the top of the motor, measured, and cut the tube down. The idea here is that the coupler gets glued into place, the motor case bolts to the coupler, and all the recovery gear goes in the nosecone. I left about 3/8" of wiggle room between the coupler and the motor case to ensure the rear closure against the bottom of the airframe is the primary load-bearing bit, rather than the coupler and the bulkplate.


Once I had everything cut and ready, I moved on to sanding prep. I sanded all bonding surfaces with 120-grit sandpaper and meticulously cleaned them with 99.9% isopropyl alcohol.

 

[UPscaler]

FIN BONDING

After the bonding surfaces were adequately prepped, I moved on to bonding the fins to the airframe. To do this, I used a modular fin alignment guide from https://hprtools.com , which made it smooth and simple! The fins were bonded to the airframe with JB Qwik Weld.


Once all the fins were bonded and given time to properly cure, it was on to more sanding and cleaning in preparation for fillets.

This rocket used Proline 4500 fillets with no additional composite layup. The fillets have a roughly 0.75" radius and were laid out with a 2" PVC elbow. I degassed the epoxy in a vacuum chamber for about 10 minutes before pouring it onto the rocket and pulling it into shape with the PVC.

 

[UPscaler]

ELECTRONICS
After the fillets were done and allowed to cure, I glued my coupler in place after repeatedly (and with much paranoia) measuring and test fitting to ensure I had the tube length and coupler placement correct to fit and retain the motor. Then, I got to work on the electronics sled assembly.

Shane from HPR Tools also designed and printed this custom sled, which houses a Featherweight Blue Raven w/ Power Perch, A Featherweight GPS Transmitter, An Altus Metrum EasyMini, and a Mobius Maxi 4K camera.


If you need a custom sled designed, @PosTart is definitely your guy.

With the all-thread installed, I slide the sled in and, once again, drove myself insane with measurements to make sure I had everything aligned for the massive hole I was about to drill into the side of this $300 carbon tube. Fortunately, I drilled it close enough that I got it shaped out pretty well with a dremel and a sanding drum.

 

[UPscaler]

Painting/Finishing
In the interest of full disclosure and revealing my fillet vanity, I did indeed sand and shape the fillets. They were good, but I wanted great. So, after shaping them, I masked them off and sprayed them with a layer of gloss black spray paint so they would still look like bare Proline. Yes, it's stupid and unnecessary, but it's how my brain works. Lol.


After the fillet paint dried, I sanded and prepped the whole rocket with 400-grit sandpaper, applied my "The Bobs" decal, and applied a mid-coat of emerald-green metallic flake from Kustom Canz, and topped that with three coats of Spraymax 2K Clearcoat. Yes, I wore a proper respirator. That stuff is no joke. I am over the moon with how cool it came out looking. I wanted to take the time to wet sand, cut, and buff it before it flew, but I didn't have time. C'est la vie.

The nosecone is two coats of Rustoleum black gloss with three coats of Spraymax 2K Clear.

 

[lr64]

Looks good. What sort of performance are you expecting?

 

[UPscaler]

The Flight
The Bobs had a successful flight to a hair over 47,500 feet on Friday morning at BALLS. The onboard video is phenomenal and I've included a couple of screen grabs. The liftoff photo was purchased from Jim Wilkerson of Tahoma Photo.


The Tinder cable cutters worked great for about 10 seconds, when it seems my shock cord wrapped around them and gave them a violent tug. Unfortunately, that led to the main unfurling at around 47,000 feet. At one point, a GPS packet indicated it was moving horizontally at over 120 feet per second. However, the Featherweight GPS gave us a great final packet as it drifted behind the mountains and the rocket was within 300 feet of it despite its indicated altitude of 2,300 feet AGL (it was on top of a mountain, so it was pretty dang close to down.)

The recovery effort was a good bit of driving and a 4.5-mile (there was a trail that took a bit of a roundabout path but saved us from having to ascend sheer mountain terrain) hike up and down a mountain with an elevation of around 3,500 feet relative to the ground level. It was pretty intense for myself and @MrPoopyPants and a harsh reminder that we're not really in shape. I digress, we got the rocket back with everything 100% intact.

 

[UPscaler]

Here is the video showing the entire build, flight, and recovery of The Bobs!

 

[Gastrok]

Just watched the "live stream" of the video - that was awesome. Amazing you retrieved it after the main opened at 47,000 ft!
BTW - I enjoy the Antigravity Group...rocket on.

 

[Papa Elf]

Glad to see the charges worked fine at that altitude. Beautiful flight!

 

[jkovac]

Great build documentation and flight! Enjoyed the YouTube livestream as well. Looking forward to your next project!

 

[UPscaler]

Here's some fun aftermath stuff. I've been told that N1000s are notorious for burning through liners and blistering cases, so I put an absurd amount of grease on the liner to help the case's life expectancy. Still, it burned through about half the liner and bubbled and blistered it all the way to the top.

Speaking of things getting very hot, the seal disk started losing its anodizing and turned purple. I kinda like it! No missing material, so it'll fly again.

 

[2-0turbo]

So what was he total distance as the crow flies from takeoff to landing? I always throw the main out at 9 miles up! 😜

 

[UPscaler]

So what was he total distance as the crow flies from takeoff to landing? I always throw the main out at 9 miles up! 😜

It was about 12 miles from the launch pad! It definitely could have been worse.

 

[Bobrogg]

what did you use for recovery?

 

[Glasspack]

That is so cool Braden !!! God Speed !!

 

[UPscaler]

what did you use for recovery?

What aspect of the recovery?

 

[rfjustin]

what did you use for recovery?

If I am interpreting the question correctly, featherweight GPS, plus an RDF beacon. @UPscaler can verify.

 

[Bobrogg]

What aspect of the recovery?

Sorry, what did you use for the main chute and do you know your decent velocity?

 

[Ronz Rocketz]

Peter Gibbons: The thing is, Bob, it's not that I'm lazy, it's that I just don't care.
Bob Porter: Don't... don't care?
Peter Gibbons: It's a problem of motivation, all right? Now if I work my ass off and Initech ships a few extra units, I don't see another dime, so where's the motivation? And here's something else, Bob: I have eight different bosses right now.
Bob Slydell: I beg your pardon?
Peter Gibbons: Eight bosses.
Bob Slydell: Eight?
Peter Gibbons: Eight, Bob. So that means that when I make a mistake, I have eight different people coming by to tell me about it. That's my only real motivation is not to be hassled, that and the fear of losing my job. But you know, Bob, that will only make someone work just hard enough not to get fired.

 

[UPscaler]

Sorry, what did you use for the main chute and do you know your decent velocity?

Main chute was a Top Flite thin-mill 70", which brought the rocket down at around 25 ft/s by the time it made it back into the breathin' air. At the top it was descending around 65 ft/s under the same chute.

 

[Theory]

Very cool! And cool to prove that BP can work at altitude so long as you know what you’re doing.

 

[UPscaler]

Very cool! And cool to prove that BP can work at altitude so long as you know what you’re doing.

and much, much higher. Kip Daugirdas' flight to 293,000 was black powder with virtually the same charge setup. Jim Jarvis, who pioneered this ejection setup as far as I know, has multiple six-figure flights with them, too, I believe.

 

[NTP2]

what is with the name, what reference am I missing?

 

[Rschub]

They are talking about charge cannons.

many posts on this topic

 

[2-0turbo]

They are talking about charge cannons.

many posts on this topic

I think he means the name of the rocket, "The Bobs."

 

[Rschub]

I understand the reference, but even though I am on their discord and Patreon I must have missed the reason for the name.

 

[UPscaler]

what is with the name, what reference am I missing?

I actually have had several different people say they love the name for various reasons. However, the name was given to this rocket by @MrPoopyPants for personal reasons. So if he wants to share, I'll let him!

 

[NTP2]

I actually have had several different people say they love the name for various reasons. However, the name was given to this rocket by @MrPoopyPants for personal reasons. So if he wants to share, I'll let him!

Ok I was thinking of the we are bob books but I couldn’t find any obvious link.

 

[lr64]

Could have been named after the a cappella singing group The Bobs. My wife says they were very good.

 

[bad_idea]

I immediately thought of the same Bobs as @Ronz Rocketz did.