Summertime MPR builds, a bigger Bull Pup and a kid-sized Katana

[novahobbies]

Just a quick thread for a pair of mid power builds I'm doing over the summer, in between other projects! I decided to pick up an upscale clone of the Bull Pup, and a downscale version of the Apogee Katana. Should be a fun set of projects!
I've always loved the Bull Pup 12D. In fact, despite my obsessive focus with models like the Explorer Aquarius, I think the BP12D is probably my favorite Estes model. Easy to build, looks good on the shelf, super fun to fly. What's not to love?
Well, the size, I suppose. Let's face it, it's a teeny model. It would be cooler if it were bigger, right?
Good for us we have a few options. You can get the Bull Puppy 2.2 and Bull Puppy 3.1 from Public Missiles via LOC's website, and they both look great. I was getting ready to pull the trigger on the 2.2 version when I noticed that Bad Boy Rocketry had one on ebay for a little less than the 2.2 version, and pretty much the same size as the 2.2, but it looked a little more like the Estes kit, and it had a simpler build profile while being just as sturdy. Plus, I've bought from BBR before and they seem on their game. So I chose that one. Believe me though.....I was SERIOUSLY tempted to get the Bull Puppy 3.1. It has a 38mm motor mount and can fly 29mm motors via an adapter, but after much soul searching I decided that the truth is, I'm not in a position to fly HPR where I live, and I'm not ready to spend the money on HPR motors versus mid power Fs and Gs, so any flight of the bigger BP 3.1 might look pretty on the pad, but would probably be a little underwhelming to fly. There's always next year.
The one I picked showed up in the mail a few days ago. I just sat down this morning to cut down the boattail, and to mark out the fin locations & cut the TTW slots. So far it's nice and easy to go together!
The size of this next to the Estes version is perfect for my field. Big enough for some oomph but not so large as to take up all the space in the trunk.


Test fitting the lower fins just a few minutes ago. I'm going to use an Estes retention ring so I need to make sure I have enough room for my top centering ring!


I like the way she looks so far. I DID get the Katana Jr in the mail yesterday. One of the little assembly jigsaw puzzle pieces on one fin came broken, but last time I checked I'm a decent modeler and I can solve that with minor fuss. Pics of that as it begins assembly....but I will probably make sure the BP is farther along before I go pulling that one out.

 

[novahobbies]

Not really an update, more of an observation. I opened the Katana Jr and went over the parts and the instructions. I'm actually surprised the Katana Jr doesn't have TTW fin construction. I know that it's not exactly necessary with just 29mm motors, but for a model that's supposed to give you practice for L1 building techniques, I'm just a little surprised. I like the E-bay sled and the instructions for that section are really well put together and detailed, same with the differences in how you mount your laundry for single and dual-deploy situations, so that lack of TTW fins just seemed odd. I've done 4 models that way to date, so I don't really need to learn it, but I sort of prefer that method for mid power rockets. Oh well. I'll just make sure we have a nice epoxy fillet and all should be fine.
Oh! Side note. I bought myself a Jolly Logic today! After watching my kid's mean machine shoot off on a baby-E and then drift.....and drift......and DRIFT.......and almost get lost, I decided it might not be a bad idea for some of those kits.

 

[novahobbies]

The basics of the BP12D are done! I used epoxy for internal fillets, and titebond thick'n'quick for the exterior fillets. I added an Estes motor retainer to the aft end, and I increased the Kevlar shock cord to 10-12 feet versus the 6 foot that was provided.
Sadly I have some sanding in my future, because a lovely glob of epoxy gooped onto the airframe as I was working and I didn't notice until it was mostly set up....also 5 minute epoxy is NOT 5 minutes in the South Florida heat. Heh. But that's all right, nothing some sandpaper, primer, and patience can't fix.




Not much left besides adding a parachute, sealing the fins, painting, decals......okay maybe that's a lot. But it looks like a Bull Pup!

 

[Pepe Le Pew]

Very nice Nova! Do you launch at Palm Bay??

 

[novahobbies]

More weekend observations about the Katana Jr. For those looking at this model, I have to say I DO like it....but like most models, it's best to go over the destructions well, and dry fit. For instance, I noticed that the 3-part fins have different root angles, so if the top half of the fin is flush with the body, the bottom half root is lifted away ever so slightly, or vice-versa if you put the bottom half flush. It's a 60 second fix with a disc sander but it's absolutely something that you need to address.
Otherwise it's going together well. I've finished the motor mount and epoxied it for extra strength, and the little joints on the fins are currently drying from a coat of wood filler. I'll start assembling the E-bay tonight. I admit I have no current plans of making this into a true dual-deploy model, I'd like to at least learn the steps.

 

[novahobbies]

Very nice Nova! Do you launch at Palm Bay??

No, I'm a little south for that. PB is about 1.5 hours north of me. My brother lives there though, with his kids. I've thought about taking some kits up to launch with his kids before....do you have any recommendations for places to launch LP and maybe some baby MP rockets?

 

[Pepe Le Pew]

I live an hour north of Palm Bay, but I go launch MP and HP there on the 3rd Saturday of the month. The groups is Spaceport Rocketry and they are then best bunch of guys to fly with.

 

[novahobbies]

The E-bay was pretty straightforward, and the directions were nice and clear. It was a lot easier to sand the sled tongues as opposed to the baffle holes tho!




The only thing I noticed was that the switch hole wasn't really well-aligned with the switch itself. I should have test-fit that before I glued the switch in. A tiny eighth inch shim would have corrected that issue, but I can still reach thru the body to press the switch in with everything assembled.


The fins are drying from their CWF now:




So far it's going together nicely. I've also put an epoxy fillet down on the lower motor mount, and added an Estes 29mm retainer ring for the motor. Not really needed, but I like them.

 

[novahobbies]

Glued thebfins down and applied a bit of primer to see what was needed. I need to sand this back down (mostly because I forgot my epoxy fillets!) But that final sanding should be all I need to get some nice smooth fins, anyway.

 

[novahobbies]

Sanded the primer back and added small jb-weld fillets to the Katana Jr fins tonight, and........I'm starting to think about actually using this model as a true dual-deploy. I was eyeing the recommended altimeter; I mean, it's not super expensive.....

 

[novahobbies]

I know.....posts w/o pics are just no fun. But even though there's no photographic evidence, work on these two models has moved along a fair bit. Both models have had (I HOPE) their final sanding on the fins to nice and smooth status. I'm still sanding away at an unfortunate epoxy glob on the back of the bull puppy. It's not huge, and not even noticeable at a distance....but it tasks me. I'm hoping to get both models in their base white by this weekend.

 

[novahobbies]

Maybe a little before the weekend! First coat of white is down on the Bull Puppy, and I'm pretty happy with the repair of the epoxy booboo. And the official grey is down on the Katana fins. I'm in a seriously humid environment so I won't be touching them until at least Saturday, but I should be able to mask them and paint the white body this weekend.



Please excuse the state of the work benches.

 

[novahobbies]

P.s., I LOVE these display supports I found on thingiverse. There wasn't one for 29mm so I just scaled it up. Prints with no supports and is very sturdy.

 

[novahobbies]

Got the "decals" (stickers) on the Bad Boy Rocketry Bull Puppy this morning! All that's left is just a clear coat to seal them, some clay in the nose to balance, and she'll be ready to fly! About 27 inches from tip to tail here.....and the Estes version is pictured for scale.

 

[novahobbies]

And the Katana Jr is painted and decalled!


I made a couple small mods. Because I had just eyeballed the paint scheme, the middle part of the Katana blade stickers wouldn't fit, so I omitted them. Also, the "cut clouds" (I guess that's what they are?) overlap the separation line just a tiny bit, so I used a fresh blade and sliced those cleanly.
I admit to one complaint, tho. It's a minor nitpick but still: I wish the decals for each side were MIRRORED, not just duplicated, most especially for the tip of the Katana blade decal and the clouds decal. It's a small thing but it makes it look like one side is facing up while the other side is facing down, and it doesn't look terribly even.
Barring a clear coat and a parachute (you know, those little things) the Katana Jr is done! I'll let this dry a couple days so the soap solution fully evaps, and maybe hit it with clear on Mon or Tues.

 

[novahobbies]

I managed to get out to the field today for a little r&r, and got quite a few unflown kits into the air....including these two! Sadly, my Saturn V Skylab was partially lost. The upper half lost its chute and pranged into a swamp area. I looked for a good 30 minutes, slogging through mud and reeds, to no avail. But that's life, and at least the bottom half retrieved fine! Some pics:










All in all, a good day! The Katana Jr and Maxi-Bull Pup flew beautifully.

 

[novahobbies]

And some vids:





There are more vids, just check my shorts.

 

[Pepe Le Pew]

Very kewl Nova! Thanks for sharing!!