Gas Gas Gas: I'm gonna run as a flash!

[Zertyme]

Gas Gas Gas: I'm gonna run as a flash!

The goal is to fly it on the H999 and the I1299.




Most of the parts come from a Darkstar Mini I got from https://eurospacetechnology.eu/index.php.
I will be using: the body tube with the slotted section removed, the nosecone, fins as stock to make the bulkheads, shock cord, and parachute.

The part between the end of the casing and the nosecone shoulder will be supported by a piece of fiberglass coupler as a sanity check.

Motor retention: threaded Aerotech closure + bulkhead on the stiffening coupler.

Fins: 2.4mm unidirectional carbon fiber plates, bonded with DP490, tip-to-tip TBD.

Electronics: Stratologger CF or AltimaxSimply 2018, tracking using an Eggfinder Mini. I also want to add a small camera such as a Runcam split3 or split4.

Ejection: surgical tubing zip-tied to the bulkhead, this is to prevent the ejection charge from being disabled during the acceleration.


Some of the parts layed down. I need a longer section of coupler :/


Because I also want to "test" the rocket on smaller 29mm motors. I made an adapter using the centerings rings and MMT provided in the kit:

Still missing the thrust plate.


To be continued.

 

[Zertyme]

Recovery fits!


This should leave enough space for the ejection charge, line cutter (or hot wire cutter), and the end of the forward closure.


______________________________


On a side note, I would like to make an interest check.
I've been thinking about manufacturing a limited run of kit, similar to Gas Gas Gas, and I would like to know if people would be interested before possibly making parts.

Specs:
-Custom 5.5:1 VK fiberglass nosecone.
-Roll wrapped 38mm, 370mm thin wall fiberglass airframe, translucent purple.
-3mm G10 fins.
-3m of 3mm Technora T12 shock cord.
-15" lightweight chute
-3d printed alignment jig
-3M DP490, enough for the fillets.

Should fly perfectly on motors up to Cti 3G and Aerotech 38/480, down to 24mm motors with an adapter. (Cti 4G would be possible but without much volume left for recovery)
Nosecone and body tube would be made by me.

Keep in mind that this is just an interest check: might happen, or not.
If you are interested, let me know.

 

[Neutronium95]

I would love a kit like that. The purple body tube sounds pretty neat. I might have to steal the idea for some of my designs.

 

[Zertyme]

Fins are made from 2mm carbon fiber plates that I had on hand. Cut using a hacksaw then finished and beveled on the belt sander.
This was my first time using DP490 for fillets. It's just perfect for fillets, non-sag, good mechanical properties, etc...

I used the mixing nozzles to first dispense an equal amount of resin for all the fillets: turns out squeezing the resin out of the mixing nozzle requires quite a lot of pressure, next time I'll get the dispensing gun.

Next is the Prepreg tip-to-tip...

 

[Zertyme]

3 layers of 150g/m² UD carbon. Root chord thickness of 3mm and tip chord thickness of 2.15mm. Leading coated in DP490 just for aesthetics (to be sanded).
Booster section weight before tip to tip: 130g
After: 140g

Wildman nosecone is nice but too heavy: so I'm trying to mold a new one.

To be continued.

 

[n27sb]

Nice work

 

[Zertyme]

Not the finest mold. The Epoxy/fumed silica mixture I used is quite brittle, thus I had to fill some of the areas with filler (dark section). Next time I'm getting a proper gel coat.
The layup was 2 layers of 160g/m² twill as sanding layer/finish, followed by 5 layers of 171g/m² S2-glass.





To apply compression I used a long ballon. Vacuum bagging was too tricky for such a small diameter and I didn't want to spend as much time and resources on a bladder. (I would have to redo the mold).


Shoulder/cone transition will need sanding and filling. Guess what else needs a lot of sanding, the cone.
Turns out it's a bit oval. I think this is due to the deformation of the mold while the balloon applies pressure on the layup.



The tip was chopped off, the inside cleaned from excess resin and I installed an AL tip from a proline cone.



The new cone is 60g.

ope
Some work was done on the fins:

 

[Zertyme]

I was also able to experiment with manufacturing my own carbon fiber plates. hopefully, this plate will be used on a 54mm CTI flying case fincan: "Don't Stand So Close"
The layup is nearly balanced and quasi-isometric.

3[90/0/+45/-45]s with a 90 plie as midplane

Post Debulk midway through the layup. This should have been done every 4-5 plies. this was a cold debulk, warm debulk would have been preferable.


Final ply

It was covered in Vacuoplex MP. Because of the microporous release film, it keeps all the resin in, but let the gases vent, right?
Well yes, unless the resin finds another path:



This picture still sparks pain in me.
The resin found its way around the Vacuoplex. I think this is due to the fact that the tool side peel ply edge was way too close to the edge of the Vacuoplex.





Tool side, flat, not twist.


Bag side, a bit of waviness. (grey marks are due to the jigsaw).


Nice and tight.

205 x 148 x 3.4mm, 157g. 1.53 g/m3, ~70/30 fiber to resin ratio.
Datasheet density is 1.81g/cm3 and 36% resin content.
Cured at 150°C

Things to change:
-Use a caul plate.
-perhaps switch to the good old peel ply/ non perf film / breather instead of Vacuoplex
-make sure the tool side peel ply doesn't extend too far.

Perhaps I should make a separated build thread for "Don't Stand So Close"

 

[Zertyme]

Received the paint today: FFB - SUBLIME GREEN it is!


I had an excellent result with this paint/clear combo before (PHG - PLUM CRAZY):


Now I'm just waiting for the weather to cooperate...



I've also designed a tower, heavily inspired by https://www.rocketryforum.com/threads/adjustable-launch-tower-build.150296/.
Two 3mm stainless steel or aluminum plate, with 20mm V-slot aluminum extrusion. The launch tower can be shortened for the H999 and I1299 flights, but I also want to be able to fly on small G motors.

 

[grouch]

Dude nice work! Looking forward to the flight report.

 

[Zertyme]

Dude nice work! Looking forward to the flight report.

Thank you.
With the current situation, it might be a bit tricky to fly the I1299 and even the H999.
I wanted to launch on the I1299 and H999 in Switzerland in March: turns out, not only I need a negative PCR test, but 10 days of self-isolation after entering Switzerland...

We'll see how the situation evolves.

 

[icyclops]

Received the paint today: FFB - SUBLIME GREEN it is!
View attachment 453625

I had an excellent result with this paint/clear combo before (PHG - PLUM CRAZY):
View attachment 453627

Now I'm just waiting for the weather to cooperate...



I've also designed a tower, heavily inspired by https://www.rocketryforum.com/threads/adjustable-launch-tower-build.150296/.
Two 3mm stainless steel or aluminum plate, with 20mm V-slot aluminum extrusion. The launch tower can be shortened for the H999 and I1299 flights, but I also want to be able to fly on small G motors.
View attachment 453628

Wouldn’t using a 3 sided launch tower like that going to cause some paint scratches when the body tube touches the rail on launch?

 

[Zertyme]

Wouldn’t using a 3 sided launch tower like that going to cause some paint scratches when the body tube touches the rail on launch?

It can scratch the paint, yes.
I planning on adding strips of UHMW or something similar to try and prevent that.

 

[watheyak]

It can scratch the paint, yes.
I planning on adding strips of UHMW or something similar to try and prevent that.

I had Teflon tape on my tower and it still scratches it.

Tower is still the best option. And the scratches let people know you were cool enough to launch from a tower.

 

[icyclops]

It can scratch the paint, yes.
I planning on adding strips of UHMW or something similar to try and prevent that.

That would be a bummer if it didn’t work.....i hate it when my paint jobs get scratched up from launches....

 

[Zertyme]

Primer/filler



Paint

 

[watheyak]

Love the green!

 

[Zertyme]

Took a total of 4h, from 600 grit to 3000 grit, and polishing.

 

[Cl(VII)]

Real pretty and structurally even better than that. Well done. Looking forward to a flight report when you get the chance to fly.

 

[Zertyme]

Well, no more Switzerland launch for quite some time: the next meeting has been canceled because of covid.
This means that I won't be able to get my hand on the I1299 or have the required waiver (3km).

Oh and, no more launch in April because we are getting another lockdown, starting Saturday.

 

[Zertyme]

Today I received some parts for the launch tower.
Of course, I'm still missing the two plates: with all the launches postponed, they can wait.
I'll probably reinforce the 90° angles with 3d printed brackets.

For anyone wondering, I got my rails from https://www.dold-mechatronik.de/

 

[Handeman]

Very cool rocket and nice build. Probably way over built, even for Warp 9 motors, but it will eat those for lunch for years.

I learned to love the i1299 in my scratch built L1 rocket. It was 2" ID, 2.25" OD mailing tubes with plywood fins and assembled with wood glue. The nose cone was pink foam turned to shape and some laminating epoxy coated on it to give it a shell. It flew great on the i1299s at 80g to about 4000 ft.

 

[Zertyme]

Very cool rocket and nice build. Probably way over built, even for Warp 9 motors, but it will eat those for lunch for years.

Thanks!
Overbuilt, just how I like my rockets

Most of my rockets will never see the launch site. For some of them the main goal is just to experiment with some building techniques (mostly composites).
There's still a few more building techniques I want to experiment with: bladder molding prepreg (nosecone), more plate manufacturing
...

All of that to later be used on "Running in the 90's" (https://www.rocketryforum.com/threads/carbon-fiber-2-stages-rocket-build.155181/post-2090708)

 

[Zertyme]

Another day, another lockdown update.
New travel restriction between departments, it should stop just before the meeting in April.... maybe... (this is getting really annoying :/)

Suprisingly, sierrafox had a few single use and reload in stock so I ordered a few.
E30-7T, F32-6T , E20-7W, G76-4G, F52-8T and F40-7W.

Hopefully I'll be able to fly a few rocket...

 

[Zertyme]

Made a plate using the leftover prepreg I had from my other project: this one will hopefully be used to make the first two kits.
The layup is as followed:

Plate layup: [90/0/+45/-45/90/0/+45/-45]s (with a 90 pli as midplan)
Overall layup: Tool/release agent/peel ply/plate layup/peel ply/perforated release film/caul plate/breather/bag

I'll replace the perforated release film with unperf, and the G10 caul plate with aluminum.
A debulk was made every 4 plies: 10min without caul plate, 10min with.

Post second debulk on the left, about to go in the oven on the right.

Tool side on the left, caul plate/bag side in the middle, and cross-section on the right.
Dimensions: 175x140x2,3mm, ~87g

 

[Zertyme]

Let's make a proper nosecone mold.

Supplies from r-g.de/en/home.html.

Parting board and walls made out of 15mm MDF, sealed with epoxy and mold sealer. I'll be using alignment dowel all along the seam.
The edge between the plug and the parting board is sealed with modeling putty.


This time, instead of struggling with laminating resin + fumed silica as first layer (brittle), I got a pack of Mould Resin P + Hardener P-25.
It's a really, really thick resin and it should provide a nice mold surface.



Mold layup will be as followed:
Mold resin P / Fiberglass strands / Coupling layer / 2x 163g/m² Twill fiberglass / 2x 580g/m² Twill fiberglass / Epoxy + Sand / 2x 580g/m² Twill fiberglass / 2x 163g/m² Twill fiberglass.

Notice that the mold layup is symmetrical: this will prevent wrapping.

To be continued...

 

[Zertyme]

Pulled the first half:

On the left, the plug, parting board, and walls ready for the layup. On the right, the mold resin was applied with a brush, followed by fiberglass strands to provide a proper mechanical bond between the mold resin and the layup. It was then left to gel.

The mold will definitely need polishing. Currently 2.8kg.


To be continued...

 

[Zertyme]

The second part of the mold:

Nearly 5kg.

I made a few "transparency" tests:
fibers: https://shop1.r-g.de/en/art/190120
Resin:https://shop1.r-g.de/en/art/100110
Dye:https://shop1.r-g.de/en/art/130155

Each sample is 7 layers thick (1mm).

 

[watheyak]

Looking great!

Is the mold back-filled with anything?

 

[Zertyme]

Looking great!

Is the mold back-filled with anything?

Yes, the mold is backed with epoxy and sand similar to yours, followed by fiberglass to keep the layup symmetric. For future molds, I will switch to Poraver to reduce weight.