Additive Aerospace 38mm (~1.6") Fin Cans now available!

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Landru

Additive Aerospace
TRF Sponsor
Joined
Nov 21, 2011
Messages
476
Reaction score
210
38mm fin cans are now officially back into production!

The latest generation cans are made from PET, and available in 3 and 4 fin configurations, with weights as low as 62g!

These cans will have no trouble breaking Mach, and have been proven up to ~M1.4 with lots of room to spare.

Currently available in Red, Orange, Blue, and Grey, and fit tubing up to 1.605" OD (thin wall fiberglass). I will be adding another tubing OD option soon for 'standard' thickness tubing.

Detailed dimensions can be found on the product page.

IMG_20181011_213435.jpg
IMG_20181011_213537.jpg
IMG_20181011_230023.jpg
IMG_20181011_230254.jpg


54mm cans will be next, as I get time to finalize the documentation.
 
Last edited:
Can the ends of the can be printed with a taper instead of blunt?
 
Can the ends of the can be printed with a taper instead of blunt?

Unfortunately not, there is a limitation because the machines have a minimum extrusion width.

There is some slight taper built into the upper transition, but I would just suggest a thin fillet of epoxy where it meets the airframe and it becomes a non-issue.
 
I have an idea. How about printing a tapered tail cone with a closure build in?
 
I have an idea. How about printing a tapered tail cone with a closure build in?
Like a motor retainer? My past experience has shown plastic retainers have a very limited lifespan for HPR, and I wouldn't trust one to hold in my motor 100%.

Or am I missing something?
 
As someone pointed out you could print a groove for a snap ring. Maybe aluminum tape is better,
 
That's pretty cool. Superglue, not epoxy?
Epoxy should work well too. Once I even used just tape, and a thin ring (think thrust ring for a body tube) glued to the airframe.
 
I may give something like that a shot.

I just worry that anything which conducts heat from the metal case would allow the plastic to soften too quickly, and potentially fail at ejection.
 
I have the 38mm fin can from Adaptive Aerospace, and it's great. Light weight, and strong. Nice!!

I'd love to see them offer this in BT-60 size. It would be a perfect start along with some thin wall fiberglass BT-60 for a minimum diameter mach buster!
 
Red,blue,grey, orange, and ??? Looks like white or silver, not “yellow”

NikeMikey
Good Catch,

Clear has been added to the color list, and Yellow is also available, just no pictures yet...
 
As someone pointed out you could print a groove for a snap ring. Maybe aluminum tape is better,
The potential issue with this is that the groove would have large forces along the weakest axis of the print - I'd be surprised if this didn't just result in ejecting the motor and the portion of the fin can aft of the groove.
 
The potential issue with this is that the groove would have large forces along the weakest axis of the print - I'd be surprised if this didn't just result in ejecting the motor and the portion of the fin can aft of the groove.

The material would likely hold at normal temps, but the motor heat transfer is often underrated.
 
Are these units paint-able ?

Best kind of paint to use ?

Surface prep ?

I've used Standard Rustoleum 2 in 1. No prep needed, though if you want to remove the layer lines it will take a lot of sanding/priming.
 
They are similar in shape to AeroTech Mustang fins. (My design. Scott Pearce) That kit has been flown beyond Mach 1 with an I132 and it's paper tube... I see no reason why they wont hold to mach 2 briefly. Be nice to find out!
 
I suspect that the only factors would be "flutter" and heating from "air friction" . . . The fin planform looks good for MACH + ( "calibrated eyeball" - LOL ! ).

Dave F.

These have the benefit of

1) Being perfectly aligned
2) Having really large, continuous fillets
3) Fins are tapered from the tube to the tip which helps with stiffness quite a bit.

I suspect they can take any commercial 38mm motor out there in a single stage configuration.
 
Back
Top