Big Purple Scratch build

So, I call this one Big Purple.
Full length LOC 2.14 air frame
Custom 3D printed nose cone, tail cone and rail button stand offs.
The 4 engine cluster is 3 canted 18mms and one center 24mm
The 3 canted motors are plugged and the 24mm is used full through for deploy
Notice the close up of the tail cone - My son did some fantastic 3D modeling there to pull off all the angles and curves.
The canted motors angle matches to the center of mass within a cm or 2 - in an effort for really straight flight.
The entire body and fins are covered in carbon fiber look vinyl wrap. - not a single drop of paint
First flight the center 24mm didn't fire (yep, not enough boost and no parachute deploy) The entire rocket survived (nose cone included).
Flight 2 was all engines go! (3-C6s and 1-D12)




[video=youtube;SfXK_yujDG8]

Have you considered hardening the inside of your tube tails ( thinned woodglue, thin CA, wood hardener? Can help with cleanup and prevent the lip from rolling up, strengthen the tube, etc.

Love that tail.

good call on the CA "stiffener" - might do that later today

Is that up to code the way the C engines just eject from the airframe during flight?

CoachSteve said:

The 3 canted motors are plugged

Click to expand...

^this

CoachSteve wins my vote for the most interesting new guy on the forum. Every rocket that he has posted has been totally different and totally awesome...

solid_fuel said:

Is that up to code the way the C engines just eject from the airframe during flight?

Click to expand...

Since I need the extra juice of the 18mm Cs I will create a vent system for the boosters for all future launches - just haven't quite got to it yet

Alright - Big Purple is now vented - should be fully cleared for proper launches - thanks for the reminder I needed to get that done.

I only mentioned that because I heard in the video someone either got hit in the head or almost in the head with an ejected motor.

I just want to say... That is one cool looking rocket!

I have a sudden urge to completely steal the design except make it airstart ready and a 29mm core... Maybe someday.

Wow, the hits just keep on coming. Love the design. I'm not a huge split fin aficionado but this one is really spiffy. Where did you get the carbon fiber-look vinyl?

Oh, and +1 for CA hardening your tube ends.

I found the wrap on Ebay - I was able to get 1' by 5' rolls for around $6 each
they have non carbon wrap as well of course - its even cheaper

Because I was using black for the fins I was able to use Black CA for fillets (effectively covering any gaps in the wraps where the fins met the body)

LithosphereRocketry said:

I just want to say... That is one cool looking rocket!

I have a sudden urge to completely steal the design except make it airstart ready and a 29mm core... Maybe someday.

Click to expand...

Do it! - Those LOC 2.14 tubes are super beefy, with the right nose cone and fins you could go way bigger that 29mm

CoachSteve said:

Because I was using black for the fins I was able to use Black CA for fillets (effectively covering any gabs in the wraps where the fins met the body)

Click to expand...

<scrambles over to a new tab to Google "black CA">

Well there's something I didn't know existed. Which variety are you using? I also found this black rubberized CA which is allegedly more flexible than the regular stuff... I wonder if it would be better for rocketry uses.

Yep - Black Rubberized CA is what I used - I doesn't fillet in the traditional sense very well but makes a good strong joint that is truly black

Here is another example of what I did with the Carbon vinyl wrap - Black Brant style

The edges of these fins are "black CAed" -

Nice BB II. Some scale decals would be a nice finishing touch.
I'm scratching my head about ejection of motor casings, cuz I know of several kits that do exactly that: most of your tumble recovery birds like Mosquito, Li'L Herc, Streak, etc. And I checked the safety codes (model rocket, high power model rocket, and sport model rocket) on the NAR website and nowhere does it mention ejection of motor casings.Yesterday there was a comment on one thread that said that ejection of motors was OK except for competition events. So maybe someone can enlighten us about that?

YMMV, depends on the org, event, club, field.

Some situations don't seem to mind a spent 18mm cardboard, I've heard of others with none or 13mm only.

oh. now that's just too cool!

CoachSteve said:

Here is another example of what I did with the Carbon vinyl wrap - Black Brant style

Click to expand...

NAR says you can't eject a motor w/o a recovery device(streamer usually) in NAR competitions, that said, spent motors clutter the field up(littering) and might be hot enough to start a fire in dead dry grass(low altitude ejection). not to mention the possibility of hitting people( eye hazard). spent motors will eventually biodegrade but it takes a while, especially if they don't go through a lawn mower one or more times. spent BP motors that is, spent composite motors are a whole nother fettle of kish.
Rex

Nice rocket Coach!

If you want to smooth the 3D print a bit you can try smearing on a coat of thin CA (I use Loctite 401) and then sanding (80 then 200 grit). Repeat. Repeat. That leaves a good smooth surface for painting. Note I use ABS for my prints, not PLA. Try it on a sample print first :wink:

Thanks for the 3D tip - My son has the printer and does all the modeling - He just recently started working with PET filiment - prints are coming out much smoother from the start. As this cone is pretty well integrated into this rocket I think I will play with the CA "filler' idea

Dude, you have skillz!

lol - thanks Bat-mite - I just have fun - been building rockets for a while - there are some guys here with True "craftsman" skills - but thanks

Have a look at this thread to see the sort of things you can do with nosecones on a 3D printer:
https://forum.ausrocketry.com/viewtopic.php?f=6&t=5019
I have applied the CA smoothing I described to this assembly.