(BAR-39) Astron Sprite Upscale

Here's an Estes Astron Scout upscaled to a BT-80H.

29mm Power

Rear Eject

I used Bruce Levinson's Ring Fin Haack with Open Rocket to check stability.

Looks like a fun build!

 2024-11-10 CAD Model and Drawings, Rev 00

 

2024-11-14: Dog Dish Ring Fin

Spent some time perusing the isles of the local Tractor Supply today and found a dog dish to make the Ring Fin from.​

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Chucked it up in the lathe and parted the side of the bowl.​

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It's a conical shape:​

7-7/16" O.D. Front x 0.128 thick​

6-3/4" O.D. Rear x 0.113 thick​

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Of course that conical shape will be aero draggy... but no worries, it's an exhibition, not a competition.​

 

Also... updated the Open Rocket Model.

 

 

 2024-11-16  Altimeter

 

The altimeter... created a pod and placed it at the base of the rocket. Also rotated the launch lug and hid it in plain sight up against the fin.

 

Greenback.... A Helicopter Recovery

This one has went through 7 different revisions to get to this point.

The rear fin can ejects and floats back to the ground on a chute, while the upper portion deploys (3) blades and spins back.

My only issue is how fast the helicopter blades will bring it down? They generate lift, so it has to be more than a quick area calculation of the blades compared to an equivalent area of a parachute.

I n any event I can't find a calculation for the decent. If you happen to know of one... hook me up.

 2024-11-12  I'd still like a calculation to determine lift and the resultant decent rate? 

I think this rocket is on hold, pending further data.​

 

 

 

 Mach Buster

Who Ya Gonna Call?  Mach Buster!    

Here's a scratch built Hot Rod Rocket made to break the speed of sound.

Main Body is BT-52H, Fin Can is BT/C-55, Nose Cone is custom turned from pine and the Rear Fins are plywood.

Power is via a G80T-10 AeroTech composite motor.

The ejection is from the rear.

The spool is made from a 3/8" dia. solid wooden dowel that is attached to the Nose Cone via a Kevlar Shock Cord. The motor has a lanyard epoxied to the hex on the ejection end of the rocket, which is also attached to the spool. At ejection the force pushes the motor out of the rocket, and the lanyard pulls the spool from the rocket.​

 

 2024-10-05 CAD Drawings, Rev 00

Lakeroadster's Fin Alignment Fixture

Inspired by this thread Homemade Fin Alignment Guide I decided to take a crack at making a fin alignment guide.

My design is basically the same as The Rocketry Forum's @qquake2k with the exception of being double sided. One Side is for BT-60 thru T-400 tubes, the other is for BT-20 thru BT-55 tubes.

Here's the CAD drawings:

 2024-09-16

Armed with the drawings I headed out to the barn to make some sawdust. I changed the design a bit, making 4 longer legs for the base.

I mocked up the parts for a visual representation... once the glue dries and I get a couple carriage bolts, I'll post up some more photos.

2024-09-17

Here's the finished jig / fixture.

I ended up using 3/8" dia. x 3-1/2" Carriage Bolts, washers and wing nuts. The wing nuts were $2.48 each?

For the mock up photos l used a piece of BT-60 and a left over plywood fin from my Spad Ace build, and that's a BT-50H for the smaller tube.