BT60 upscale of Odd'l Break Away

[snrkl]

I really like the idea of a rocket that needs no wadding or parachute.

I took one look at the Odd'l Rockets break away and thought: I want!

Then I realised how small it was with TVM holding it and decided immediately: not big enough for me.



Given my propensity for BT-60 body tubes and the fact I had exactly 5 apogee tube couplers left over from my 2 stage build: the dimension gods had spoken - it would be BT60!

A suitable nose cone was available from my latest Estes designer special... (and is the same profile I used on my kraken clone...)

I figured out the scaling ratio and used the rocksim scaling mechanism to scale it to BT-60.

Printed fin templates and we are off to the races.

BT is all cut and couplers glued.
MMT is built (engine block to be installed when I've next got epoxy out)



Decided to use tape retention over a retention hook.

Fins will be papered shortly using printer labels (man, its sooooo easy with sticky labels!) then ca sealed edges and glued.

I've started using CWF to fill plastic NC seams - I harden the sanded CWF with thin CA and it looks 'super slick' great...

Next decision is do I print and cut a foam board fin jig (I don't have a BT-60 3F one already) or do I spend the time getting my new Estes fin jig assembled... pondering...

After fins it's straight to the paint shop. I've decided to make each segment a colour of the rainbow - fins currently planned for black but the jury is still out.

After that I need to do some thinking on shock cord attachment into each tube segment. (I've offered Odd'l to buy a copy of the instructions - I like to support innovative product design and always feel crappy cloning an awesome kit!)

My thinking is to use a small piece of BT wood glued over the shock cord (with a knot or two either side to limit travel.

I'll attach the rkt file once I'm back at a desk.

 

[dhbarr]

Glue a launch lug into each segment, then thread and knot?

 

[snrkl]

Glue a launch lug into each segment, then thread and knot?

Looking at the kit breakout on Appogee's website, it looks like they use small BT segments in the smaller kit - this is where my thinking was at..



If I use launch lugs, my thinking is that the knot would have to be huge - if I want this to break apart properly, I am thinking that the shock cord will need to be taught to yank the next segment out.. I am hoping that drag when falling encourages all the remaining segments to follow suit.. no real way to sim this, so I guess it will be a "fly it and see" test...

 

[snrkl]

RKT file: View attachment BT_60_Oddl_Break-Away.rkt

and pics...

 

[hcmbanjo]

Glue a launch lug into each segment, then thread and knot?

If you used a launch lug the Kevlar would tear right through it!

 

[hcmbanjo]

Looking at the kit breakout on Appogee's website, it looks like they use small BT segments in the smaller kit - this is where my thinking was at..

View attachment 325253

If I use launch lugs, my thinking is that the knot would have to be huge - if I want this to break apart properly, I am thinking that the shock cord will need to be taught to yank the next segment out.. I am hoping that drag when falling encourages all the remaining segments to follow suit.. no real way to sim this, so I guess it will be a "fly it and see" test...

Those small pieces are reinforcements that glue down under the knot position in each coupler.

 

[jadebox]

Looking at the kit breakout on Appogee's website, it looks like they use small BT segments in the smaller kit - this is where my thinking was at..

View attachment 325253

If I use launch lugs, my thinking is that the knot would have to be huge - if I want this to break apart properly, I am thinking that the shock cord will need to be taught to yank the next segment out.. I am hoping that drag when falling encourages all the remaining segments to follow suit.. no real way to sim this, so I guess it will be a "fly it and see" test...

Having built and flown a bit larger upscale of the Breakaway ...

https://www.rocketryforum.com/showthread.php?10846-YouBee-Build

The ejection charge will pressurize the entire inside of the rocket, so, assuming that none of the couplers are sticky, all the pieces will move apart relative to each other. You don't want the shock cord to become taught because that might make the parts rebound and hit each other or cause a zipper. The shock cord between each segment also should be long enough so that each part falls pretty much independently. This will allow each part to tumble, slowing the descent and increasing the"Wacky Wiggler" effect. One thing to consider is to try to avoid anything that the shock cords might catch on inside the rocket.

-- Roger

 

[jadebox]

See also: https://www.rocketryforum.com/showthread.php?40716-Breakaway-2-6-quot-upscale-build-The-Castaway

PS ... I prefer the original "Rainbow" paint scheme for the Break Away over the new "Where's Waldo" scheme that Odd'l Rockets is using on the face card for the kit now. Sorry, Chris.

-- Roger

 

[snrkl]

Those small pieces are reinforcements that glue down under the knot position in each coupler.

I now understand how this is put together in the kit...

Unfortunately, I have already glued the couplers into the tubes... (and my build has the couplers on the tops of the tube segments, not the bottom...)

so a small retrofit - the plan is as follows: taking small 30mm lengths of BT60, I take a vertical slice out of them and make them into tube couplers.

Two small holes for the kevlar to be looped and knotted through. Another small piece of horizontal slice of BT to go under the knot (and glued down) , then the whole thing inserted and glued in BEHIND the tube couplers.

It will add weight, but unless I start from scratch (and either build or order 5 more couplers) this is what it is...

I'll take a pic and post once I have built the first one.. I need to paint the body segments before final assembly...

Fins went on tonight (I ended up prepping the estes fin jig) and I am about to fillet them before bed...

 

[snrkl]

Build update: primary construction is complete (minus tube interconnects - this will have to happen after paint...)



Small fin alignment issues with my first use of the Estes fin jig - Two of the fins are 1mm further aft than I wanted them to be and overhang the aft end.. the jig made it hard to align by touch on the aft end (I thought they were aligned but.. they weren't...) something to watch out for next time...

 

[snrkl]

Got the gang out today.

It was a mad frantic juggle to get the whole thing done under an hour, so no progress pics were taken.

In order to get smooth paint I had to get final coats down within an hour of starting (second coat within 1 hour or after 48) so the race was on...

I primed with a grey high fill primer (two coats) waited 15mins (its quick drying) sanded with 400grit, wiped (norwex cloths are fantastic for paint prep) two coats of flat white primer, dried 15 mins then shuffled each segment onto a common BT60 scrap to protect the couplers and painted the various colours..

Let sit for a few hours and now I've recombined so it can sit to dry properly for a few days without it taking up so much room...

Fins are going to be colour shift so once it's dry enough to mask (later next week) I'll flat black the fins then colour shift over the top...

(intentionally horizontal...)

I'll say this though, the British paint cans are 1/2 the price of the rustoleum, but I know where the money goes...



That light pink line on the fin fillet isn't light reflecting - that's just really thin paint that doesn't adhere well, leaving the coat REALLY thin in places...

 

[neil_w]

I've had my eye on the Breakaway for a while (just the regular kit, no plans for upscale). My first thought was to paint it ROYGBIV, but then I thought, what a huge pain in the neck, no way. Also didn't want to invest in that many cans of paint. How you managed to pull this off in a single painting session is amazing. It looks fantastic!

I have to say, I'd have been nervous to attempt this upscale without having first built the kit, in terms of getting the whole breakaway mechanism to work reliably without the considerable experimentation and refinement that Chris performs when developing his kits. Looking good so far, though, and I am really eager to see flight video on this.

 

[snrkl]

I've had my eye on the Breakaway for a while (just the regular kit, no plans for upscale). My first thought was to paint it ROYGBIV, but then I thought, what a huge pain in the neck, no way. Also didn't want to invest in that many cans of paint. How you managed to pull this off in a single painting session is amazing. It looks fantastic!

Once I figured out the 1hr or 48hr rule (and 72hrs on plastic...) painting has become MUCH easier.. Also, I cannot speak highly enough of the solvent proof frisket film.. holy crap it was easy... and I already had a wide variety of colours.. rockets with kids means I have accrued many colours over the last 9 months...

I have to say, I'd have been nervous to attempt this upscale without having first built the kit, in terms of getting the whole breakaway mechanism to work reliably without the considerable experimentation and refinement that Chris performs when developing his kits. Looking good so far, though, and I am really eager to see flight video on this.

I would have started with the kit, but kit shipping through anyone but amazon ends up costing 3x the cost of the kit, so it is cheaper to build from parts and trash it then to experiment with the kit first...

Also: I haven't flown it yet, nor have I installed the retention mechanism (didn't want to have to paint it with it all tied together!!) Next launch day is on the 20th, between my scratch built 2 stage and this, I expect to have some time chatting with the RSO...

 

[snrkl]

Also, hcmbanjo was nice enough to nudge me in the right direction on how he solved the "keeping it together" problem on the actual break-away...

 

[snrkl]

I've started the "better coupling retrofit"...

I've made some BT segments into shock cord mounts.



Once the reinforcing strips are dry (wood glue) I'll Wick a very small amount of thin CA into each hole, then, as I reef knot (you Janquis call it a square knot) tie each strip I'll be wood gluing the sections into each BT segment.

I have a foot of Kevlar shock cord for each segment, which should be plenty... the upscale calls for 8", but I've got it spare, so more's the better, I figure...

Segment gluing will have to wait for the fins to be black then colour shift painted.

I'll be masking the fins, but I'm going to try blending the black/colour shift into the purple - figure blending rattle cans is a good skill to improve on...

Worst case scenario, I'll just paint the whole fin if I screw it up...

 

[snrkl]

Ok - so we're now finished construction:

Square knots duly tied:



And the shunt installed and glued with wood glue:




Paying particular attention to ensure the shunt didn't interfere with the couplers.

Couplers are CA's and 600grit "polished" and are all silky smooth to slide on/off as suggested by this rockets original designer.

All done:


Fins are blended colour shift, which looks great in the sunshine. I've taken several rotation shots to try to share the #awesome...





The blended purple to black (colourshift should be sprayed on black) worked much better than I thought it would...

My only regret on this beast is using the light/dark blue I already had, rather then dropping out the dark blue and getting a lighter cyan blue, but hey.... I used the paint I already had...

 

[neil_w]

Looks fantastic!

When's it gonna fly? I'm psyched to see some flight videos, and also flight data from your Alt3 to see what kind of descent rate you get out of this thing.

 

[snrkl]

Sunday is the day... I'll post what I get... I haven't simmed with the Alt3 yet, but hey, I get to choose from 5 different segments to mount it, so I'm sure one will be awesome! 😜

 

[snrkl]

Incidentally, I was tempted to jam my $7 808 clone inside the BT at the top and fly it - figured it might make for some interesting video... but alas, the 808 clone suffered the same terrible battery fate they all do...

It's a shame because I actually like how the clones are 30% of the weight of the real ones...

 

[snrkl]

So I flew this twice today. Both flights went well. (Super windy day - 20-25km/h winds - launch almost got scrubbed half way through)

A teeny tiny amount of the start of a zipper on one of the couplers - before I fly it again I'll likely CA the inside of the couplers (can't believe I didn't think to do this in the first place)

As requested, video showing the tumble recovery (gets lost but picked up again at ~1:43)

https://youtu.be/dIPsBTQXckc

Altimeter added to capture descent rate (8.1m/s)



And a shot of how it landed:
Flight 1:

Flight 2:


So all up a super fun rocket and Sooooooo easy to fly:

insert motor, push button, look up, smile!

 

[Woody's Workshop]

That looked like a fun build brother!
I bet it was a hoot to watch come down!
I like the way you went with the paint as well.
Well Done Sir.

 

[hcmbanjo]

Great to hear a good flight report!
Now that you've up-scaled the Break-Away, how about a MicroMaxx downscale?

 

[snrkl]

Great to hear a good flight report!
Now that you've up-scaled the Break-Away, how about a MicroMaxx downscale?

View attachment 326259

I think my lounge room is too large to fly that in - I'd lose it! 😜

 

[snrkl]

Some pics from another QRS member of the upscale breakaway in action: