Carl (or anyone who might know),

I'm getting conflicting lengths on the A300 and A300A "Sparrowbee" variants. Were there differing lengths (differing Sparrow models) for these upper stages?

The dimensions given by one source put the total length of the 300A's Sparrow at 113", counting the mating section just below the skirt of the Sparrow. I get a length of 122.41" for the earlier A300's Sparrow, measured to the same location.

Are they both right?

Revised Plan -- AeroJet 2.5 KS - 18000 Booster Stage
 

I have been having some issues with the data sheets I was originally using, but thanks to Carl and Don, I now have a better grasp of the dimensions for these Aerobee variants. Below is a more detailed plan for the early three-fin booster, having a length of 78.04".

As before, I'm using a Pete Alway interface idea that Pete used on his BT-60/BT-55 semi-scale model 20-odd years ago. My take on the his original idea is to countersink the support columns into the outer edge of the forward transition, and to sand flats into the dowel stock where they contact the inside surface of the coupler.

The tailcone is not a flight component, but for display. It pops out to allow access to the motor tube.

Revised Plans -- A150 and A300, with booster
 

Here's the 4th revision I've worked on, but this time I think the dimensions are much better.

Aerobee 150 Standard:

Length: 35.660"
Diameter: 1.54" (BT-58)
Fin Span: 6.225"
Weight: 3.16 oz


Aerobee 300:

Length: 39.121"
Diameter: 1.54"
Fin Span: 6.225"
Weight: 3.17 oz


Flight simulation comparisons:

Note: All flights use the D12-0 booster motor. All launch rods 48" x 3/16".


A150......C11-5......1243'......Dv 19 FPS
A300......C11-5......1234'......Dv 18 FPS
A150......C6-5.......1338'......Dv 8 FPS
A300......C6-5.......1331'......Dv 7 FPS
A150......D12-5......1629'......Dv 21 FPS
A300......D12-5......1619'......Dv 19 FPS
A150......E9-6.......2161'......Dv 10 FPS
A300......E9-6.......2152'......Dv 10 FPS


Now perhaps I can get the A150A and A300A to work out right... :o

Enjoy!

New Designs -- Aerobee 150A and 300A, with booster
 

Finally got these ready. The four-fin version takes about a 5% to 10% penalty overall.

Aerobee 150A:

Length: 35.66"
Diameter: 1.54"
Fin Span: 7.325"
Weight: 3.34 oz


Aerobee 300A:

Length: 39.121"
Diameter: 1.54"
Fin Span: 7.325"
Weight: 3.28 oz

All simulations use the D12-0 in the booster, and a 48" x 3/16" rod.



A150A......C11-5......1147'......Dv 9 FPS
A300A......C11-5......1144'......Dv 11 FPS
A150A......C6-5.......1234'......Dv 14 FPS
A300A......C6-5.......1231'......Dv 17 FPS
A150A......D12-5......1503'......Dv 14 FPS
A300A......D12-5......1499'......Dv 13 FPS
A150A......E9-6.......2005'......Dv 16 FPS
A300A......E9-6.......1995'......Dv 21 FPS


I might look at the Aerobee 350 next. It uses a Nike booster... :D

Enjoy!

Revision for Sparrow upper stage
 

When I posted the A300 and A300A plans, I forgot to include the little antennae just below the nose cone. Shown here is a revised partial plan of just that upper section, with those antennae in view.

The base of the stage is a single piece of balsa. I had to show it as two pieces because RockSim would not allow me to show it any other way...

Partial Plan -- Aerobee Series-A 4-Fin Booster
 

Here's the booster for the "A" models, all by its lonesome...

Like the 3-fin version, the tail cone is a turned balsa component, and is only used for display.

New Design -- Sandia Tomahawk
 

Here is the base single-stage 9" diameter Tomahawk, with a length of 209.5", based on the ROTW page 143 diagram. Good flying model, if we only had Carl's motors! (Hint, hint...) :D

Length: 20.95"
Diameter: 0.908" (ST-8)
Fin Span: 3.66"
Weight: 1.094 oz


1/2 A6-2......106'......Dv 14 FPS
A8-3..........271'......Dv 15 FPS
A5-4..........318'......Dv 6 FPS
B4-4..........617'......Dv 30 FPS
B6-4..........636'......Dv 29 FPS
B4-5..........741'......Dv 1 FPS
B6-5..........755'......Dv 12 FPS
C6-7.........1304'......Dv 27 FPS
C6-6.........1385'......Dv 5 FPS


Enjoy!

New Design -- Nike-Tomahawk
 

I did not two-stage this simulation, so that I could keep the design simple. It is large enough that it might be possible, but I think it would require electronics, and that would mean additional weight, meaning it would need composite motors...

Simple is sometimes better... :D

Length: 36.89"
Diameter: 1.70 (ST-16; The extra is the bulge of the transition.)
Fin Span: 6.30" (Nike fins)
Weight: 3.02 oz

All simulations require a 48" x 3/16" rod.


C11-5......450'......Dv 21 FPS
D12-5......906'......Dv 6 FPS.......Optimum motor
E9-6......1411'......Dv 14 FPS......Second-best motor


Enjoy!

Re: Sandia Tomahawk
 

9" in diameter, 209.5" long (17 ft., 5.5 in.) and yet it reaches 106' on a 1/2A? Wow, impressive! :D

Mark \\.

It is one of Carl's motors, after all... :D

Caveat on the motors: I'm using data that I generated in the RockSim motor editor, based on Carl's "Small Engine Families" datasheet. The thrust curves might not be accurate, but they do fit the numbers given. My pressure build-up times might be a little slower than the actual product, so the real motors might jump a little faster off the pad.

I want to flight-test some to find out!!!