3D printed fin can - laserloc tribute rocket

[ether]

One of my next projects, inspired by the laserloc 3.1, but with updated materials

PML components: fiberglass nosecone, UL 3.0 carbon fiber airframe - traditional dual deploy - main and payload bay
Thundercloud: custom printed fin can, 3.0 external diameter with air foiled fins
54MM carbon tube for motor tube - awesome tube from Rek

Designed the fin can to be same diameter as the airframe and be removable just in case i want to switch the fin design or for servicing. designed it around the largest 54MM motors - should go slightly above mach 1 and around 14-15k ft

should be a great sport rocket to have in the fleet, will take a while to build as other projects are in the queue

 

[XrayLizard]

Makes me want to get a printer!

what is the weight of the fin can?

 

[ether]

604 grams

one fin in G10 material by itself would be around 100 grams, should be about neutral in terms of weight vs traditional build method

went with the 3d printed route to make it as simple to assemble as possible and get some features built in, diamond airfoil of the fins and integrated tail-cone

should be a very straightforward build - will use min diam type motor retainer inside the airframe to hold it together

 

[XrayLizard]

Please may I ask, What is the length and fin span?

I have understood the trade off is weight versus design ability
Wondering if I want to go the Creality printer route.

 

[JDcluster]

What's the fin can made of? If it's PLA, don't launch it unless you are on the dark side of the moon.

 

[FredA]

Say goodbye unless you launch on the wimpiest motor ever.

 

[ether]

Is it not fun to post things up, love the comments

 

[o1d_dude]

want

 

[ether]

Please may I ask, What is the length and fin span?

I have understood the trade off is weight versus design ability
Wondering if I want to go the Creality printer route.

root cord 12", span 3.5", tip 1.25" and sweep angle 70 degrees

 

[ether]

What's the fin can made of? If it's PLA, don't launch it unless you are on the dark side of the moon.

similar properties as ABS

https://www.3dfuel.com/collections/pro-pla

 

[ether]

Say goodbye unless you launch on the wimpiest motor ever.

yupp agree will use a wimpy L935, don't want to push it that hard, nice and gentle

 

[ether]

Please may I ask, What is the length and fin span?

I have understood the trade off is weight versus design ability
Wondering if I want to go the Creality printer route.

the weight penalty may not be there really, just weighed same the section length of carbon tube, 2 centering rings and 3 g10 fins - without epoxy, its about ~450 grams.. if you swap out a FG tube then i would venture it would be around 550-600 grams - then if you consider the weight of epoxy it might actual come out weighing less

the penalty might be from the fin thickness, made it thick at the root then tapers off at the tip, but then you get a great diamond profile and looks awesome. pros and cons to everything

 

[JDcluster]

I'm not trying to knock your design, just trying show you the possible failure that you can avoid before hand.
The fin can will melt in your car.

Will it stand up to the temperature range it will see from heat from the motor?

similar properties as ABS

https://www.3dfuel.com/collections/pro-pla

 

[ether]

I'm not trying to knock your design, just trying show you the possible failure that you can avoid before hand.
The fin can will melt in your car.

Will it stand up to the temperature range it will see from heat from the motor?

no it would not, heat from the motor would burn the material, let alone the heat from the motor case.. have you seen what the temps allowed are for commercial cases, very toasty

https://www.nfpa.org/codes-and-stan...st-of-codes-and-standards?mode=code&code=1125
220c is the spec temp

happy to answer questions

 

[ether]

here is some great practical testing of motor case temp, very useful for thinking through design parameters

https://www.nakka-rocketry.net/therm.html#Testing

 

[Neutronium95]

That looks gorgeous. When you say it's designed for the largest 54mm motors, does that include the motors that go in Loki 54/4000 casing?

I've heard of well designed 3D printed fins surviving up to around Mach 2, so the fin can should hold together. Please post pictures when it flies.

 

[ether]

should put an asterix on that statement.. *California legal, so aerotech and CTI

technically the airframe would fit that long motor, but will setup the motor retention to accept the longest CTI motor

this one is meant for fun, got another rocket on the design board that is between this and my L3 rocket, will be 75MM mount and that one should be a screamer

 

[Neutronium95]

should put an asterix on that statement.. *California legal, so aerotec and CTI

I know that pain. I have a few designs based around Loki motors. I doubt that they'll ever leave the Openrocket folder until I can figure out a way to get a reload shipped to someone, and then meet them and fly it out of state.

 

[ether]

I've heard of well designed 3D printed fins surviving up to around Mach 2, so the fin can should hold together. Please post pictures when it flies.

others have paved the way and done the hard work of pushing the limits, i did 3d for style and ease

at most expect the leading edges to suffer if at all, will do a thin layer of epoxy to help it a bit, but if they deform will then repair with some sort of inserts/caps (composite or aluminium), pretty confident it wont be an issue at these relatively low speeds

 

[beeblebrox]

Say goodbye unless you launch on the wimpiest motor ever.

Why? Apparently you do not understand how strong PLA is... I have several 3d Printed fin can rockets that have flown with no problems. I have seen a rocket with Estes Styrene fins shred on a smaller motor. Its construction techniques...and design. That fin can shown will easily hold up as long as there is a paper motor mount tube inside for insulation. It has a nice long root and great fillets. If minimum diameter the fin can might fail after the flight during heat soak phase, but the flight is over then...print another for $3 I have a 2.6" diameter rocket I am planning to fly at Bonneville Salt Flats in a couple of weeks, The fin can is a boat tail down to 1.6" 38mm motor mount. fins are three pieces each. PLA+ outside airfoiled parts and 0.030" G10 Fiberglass sheet core. Plan to fly it with an I400, if windy, an H168, will try to remember to get flight photos... I keep forgetting that I can take 1000's of photos with my phone...DOH My brain still is conservative like I'm using FILM...Remember that stuff!!!

 

[FredA]

I print PLA and have broken several prints along the layer-line.
Maybe this will work - but I wouldn't try and I would be very careful with the print direction.

H-Motors, no problem. L's are a different story.
But I'm coming from a viewpoint that my motors tend to rip the fins off of almost any MD rocket --- YMMV.

Good Luck - keep us posted