And the "I shattered my rocket into a million pieces" award goes to...

[jordan.jacob]

My college's team, Grizzly Aerospace, attended the Rocketry of the Southern Stars (R.O.S.S.) event hosted by Clemson University this past weekend. We know 3D printing can be fragile, but we didn't expect to have 20 minutes worth of cleanup after launch.

Luna Mk V Maiden Flight - Rocketry of the Southern Stars (R.O.S.S) Event

 

[Rob Campbell]

 

[Steve Shannon]

Perhaps instead of scaling up the BT and motor mount, your team should work out the kinks with recovery first.

 

[jordan.jacob]

Perhaps instead of scaling up the BT and motor mount, your team should work out the kinks with recovery first.

We're upsizing to 75mm motor mount and a 6" diameter. This should resolve the recovery issue, as the parachute was slightly too big.

 

[Hobie1dog]

 

[CalebJ]

We're upsizing to 75mm motor mount and a 6" diameter. This should resolve the recovery issue, as the parachute was slightly too big.

Why not adjust the parachute size with the existing design?

 

[tsmith1315]

Wow, thanks for posting!

 

[jordan.jacob]

Why not adjust the parachute size with the existing design?

The existing size wouldn't be able to hold the payload required for the competition. We have to implement a 100x100x300mm CubeSat.

 

[pathtouch]

Loved the telemetry overlay. Did you pay for that software or find a freeware version to accomplish that?

Good luck scaling up.

 

[KenECoyote]

What material was that rocket printed in?

Also sorry for the failure... definitely painful to pick up the pieces, but we do these things not because they're easy...

 

[Banzai88]

We're upsizing to 75mm motor mount and a 6" diameter. This should resolve the recovery issue, as the parachute was slightly too big.

That should have been self evident on recovery packing and during ground testing.

 

[jordan.jacob]

Loved the telemetry overlay. Did you pay for that software or find a freeware version to accomplish that?

Good luck scaling up.

I paid for Telemetry Overlay. Well worth the money! I made the gauge background in Photoshop, added it as a gauge itself, and overlayed the actual data on top of it.

 

[jordan.jacob]

That should have been self evident on recovery packing and during ground testing.

We didn't have a chance to ground test when we put the larger parachute in. It was moving freely when we packed it in the tube.

 

[jordan.jacob]

What material was that rocket printed in?

Also sorry for the failure... definitely painful to pick up the pieces, but we do these things not because they're easy...

Polymaker PETG

 

[KenECoyote]

Polymaker PETG

Ah, thanks for that info. That's surprising to me since PETG is more durable and impact resistant than ABS and it didn't look like you launched in cold temperatures. I was surprised by how much it shattered.

 

[ThirstyBarbarian]

We're upsizing to 75mm motor mount and a 6" diameter. This should resolve the recovery issue, as the parachute was slightly too big.

Too big, as in too big to slide out of the tube freely?

I thought I heard on the video someone saying a battery had come disconnected. Did that have any part in the recovery failure?

 

[KenECoyote]

BTW- regarding the shattered award... I once helped a guy pick up a million pieced of his hp 12"+ diameter foam rocket that cato'd on the pad. We had to get every piece of foam (even ones blowing away) since we were launching off a working farm field.

 

[jordan.jacob]

Too big, as in too big to slide out of the tube freely?

I thought I heard on the video someone saying a battery had come disconnected. Did that have any part in the recovery failure?

Yeah, the parachute's diameter was too big to come out after the ejection charge pushed it down in the tube further. The battery disconnected when it crashed, and we lost the GPS signal.

 

[jordan.jacob]

BTW- regarding the shattered award... I once helped a guy pick up a million pieced of his hp 12"+ diameter foam rocket that cato'd on the pad. We had to get every piece of foam (even ones blowing away) since we were launching off a working farm field.

That's insane. At least the PETG didn't blow around!

 

[rfjustin]

The existing size wouldn't be able to hold the payload required for the competition. We have to implement a 100x100x300mm CubeSat.

Respectfully, moving to larger scale on the heels of a failure is recipe for more failure. I would measure success on the current size, and scale up from there...

 

[SolarYellow]

Yeah, the parachute's diameter was too big to come out after the ejection charge pushed it down in the tube further. The battery disconnected when it crashed, and we lost the GPS signal.

How about placing the ejection charge so it pushes the chute out of the tube instead of "down in the tube further?"

 

[jordan.jacob]

Respectfully, moving to larger scale on the heels of a failure is recipe for more failure. I would measure success on the current size, and scale up from there...

Being a competition rocket, we don't have the time. We have a month and a 1/2 to have our competition rocket finished. We've succeeded on similar designs with smaller parachutes, just hard landings breaking the fin section.

 

[jordan.jacob]

How about placing the ejection charge so it pushes the chute out of the tube instead of "down in the tube further?"

Shouldn't be an issue anymore with the upsize.

 

[Jester]

Just a suggestion for consideration, a longer shock chord may help in more ways than one. Good luck!

 

[FredA]

How come the telemetry is backwards?
Would expect positive G's during the burn.
Altimeter upside-down?

 

[Rob Campbell]

How come the telemetry is backwards?
Would expect positive G's during the burn.
Altimeter upside-down?

Satanic backward masking?

 

[jordan.jacob]

How come the telemetry is backwards?
Would expect positive G's during the burn.
Altimeter upside-down?

I set it that way on the telemetry overlay only to show the forces acting on the rocket. The scale shows + on the bottom.

 

[Charles_McG]

How come the telemetry is backwards?
Would expect positive G's during the burn.
Altimeter upside-down?

It -is- positive Gs during burn, the display scale is inverted. I'm thinking so the meter looks like flame.

 

[Worsaer]

You need multiple ground tests and some practice flights to get your recovery system right.

The up part is easy. But many things can go wrong with ejection charges and getting the laundry out. Like anything else, practice will make you better.

 

[jordan.jacob]

You need multiple ground tests and some practice flights to get your recovery system right.

The up part is easy. But many things can go wrong with ejection charges and getting the laundry out. Like anything else, practice will make you better.

Thanks. Not too worried about it, honestly. We've had successful flights with this design. We just put too large of a parachute in this time, and it got hung up in the body tube. The upscale to a 6" diameter will resolve this problem. Nose Cone is printing now.