GDJ's Oddrocket: The tripod handle-rocket

[GDJ]

This started out as a joke, but as I worked thru the numbers on Openrocket, the less of a joke it became and it became reality.

The nose-cone-lid-bodytube-transition is a handle from a cheap camera tripod (y'know, the really bad ones that do everything EXCEPT keep a camera steady). It's hollow, about 1mm thick, the cap is rounded, and the piece that slips (glued actually) into the shiny bodytube has a 9mm hole thru it's axis. The nose assembly will house the 10cm (4") 4 string parachute and the wadding.

The shiny bodytube is home-made from office paper rolled on a chunk of 1/2" threaded rod from work, then wrapped with 4 feet of 1" wide Mylar tape (about 0.0005" thick).

The fins are 1.5mm 3 ply birch cut with a hobby knife, and knifed edged on the flight surfaces. They are mounted on a cardboard tube "fincan".

Without the stand, it stands at approximately 235mm or 9.25" long.

It runs on a Estes A3-4 engine (13mm size).

The scary thing is that OpenRocket simulates this rocket at just over 550 feet apogee. Even if it gets under that, it's a success!

 

[Aksrockets]

Looks awesome.
FLY IT!!!

 

[GDJ]

Looks awesome.
FLY IT!!!

Oh it will fly, but right now is only about 1/2 done.

What's left:

-Parachute
-shock cord mounting
-Launch lug placement

The last one is the tough part. This thing is so small and so light that a standard single launch lug with a short standoff will yank it right off course.
I may have to mount a 2nd launch lug 180º from the first one, or mount them on opposing fins to knock down the drag.

But I'm working on it!


EDIT: Made some dumb errors on OR pertaining to the recovery system. Too heavy and too large a chute. I corrected the errors and weighed the rocket as a whole.
Apogee is now 590 ft on a Estes A3-4 engine.

 

[GDJ]

Finished the rocket tonight and painted the fin can and fins with white Epoxy paint. It's slow drying stuff, but when fully dry it's as hard as a rock and moisture resistant.

Mounted 2 launch lugs on opposing fins to balance out the aerodynamics. Looks interesting.

 

[jeffgeraci]

I don't get where the cone separates to release the recovery system.
In the pic it looks like the cone is taped to the airframe? Start splaini'n Lucy!

 

[GDJ]

I don't get where the cone separates to release the recovery system.
In the pic it looks like the cone is taped to the airframe? Start splaini'n Lucy!

No problem.

The nosecone assembly (small shoulder-transition-body tube) is actually one piece. The shoulder is 30mm long and is bored out with a 9mm hole (slightly under 3/8"). The nose cone is a short rounded cap at the top of the whole assembly. This houses the wadding, Micro-Parachute and shock cord, not the shiny body tube. That's simply a long engine mount with a fincan on the bottom.

Basically it's a hollow plastic handle that used to have a threaded rod in the end where it screwed into a camera mount assembly. I just modded it slightly to suit a 13mm bodytube and A3-4 engine.

So, main rocket on the left, Parachute centred, Nosecone "cap" on right.
Front bodytube/transition is one piece, on the main rocket.

View attachment Geoff's tripod handle Micro-rocket.ork

 

[jeffgeraci]

Ah, I get it now, thanks for clarifying... and can I just say, that is one seriously home-made ugly-@ss chute: I like it!!!

 

[Rex R]

so now he can do do the 'flying of the handle' routine .
rex

 

[GDJ]

Ah, I get it now, thanks for clarifying... and can I just say, that is one seriously home-made ugly-@ss chute: I like it!!!

The Mylar in the center of the 'chute is on purpose. The two strips stuck together act like a hairspring that springs the 'chute open.....as long as the mylar strip doesn't get creased.

so now he can do do the 'flying of the handle' routine .
rex

Hee hee!

 

[GDJ]

UPDATE (Long overdue)

Rocket has flown 7 times, all successfully.

The original parachute was a piece of crap, so it got a new one made from a plastic Safeway grocery bag (the really crappy thin ones! )

It's not a real high flying rocket, but it is consistent and true, and that counts for alot.

 

[GDJ]

UPDATE on this old girl:

Has flown 20 times, and the original office paper body tube has given out.

Now sports a new BT-5 tube, new 0.79mm fins, a proper standoff for the launch lug, and just for whimsy I glued on 3 more fins at the CG.
Looks meaner in a puny way.

Shortened up the body tube down to 100mm, and with the new fins it has a projected apogee of 705 feet. Not bad for a 13mm mini-motor.

Pics to follow soon....