Medusa’s Wild!
Level 2 Project: A two-stage Scratch Design
Mike Brest TRA #9383
(Last Update 10-10-04)
Background
I need to
build a rocket to certify Level 2 with, and I’m not prone to following the
K.I.S.S. theory. I’ve always been most
interested in staging and clustering.
Soooo, I decided to build a two-stage rocket that covers all these
needs.
|
Rocket Specifications |
|||
|
|
Sustainer |
Booster |
Overall |
|
Diameter |
4” |
4” |
- |
|
Length |
8 feet |
5’ 6-1/2” |
13 feet |
|
Fin Count |
4 |
4 |
8 |
|
Motors
(14) |
29/240 (4) 54/2560 (1) |
29/240 (4) 38/600 (4) 54/2560 (1) |
29/240 (8) 38/600 (4) 54/2560 (2) |
|
Fin Semi-Span |
5.5” |
7.5” |
- |
|
Flight
Weight (no motors) |
16.75 lb |
20.0 lb |
36.75 lb |
|
Flight
Weight (w/ motors) |
23.4 lb |
31.5 lb |
54.9 lb |
|
Decent
Weight |
19.5 lb |
24.8 lb |
- |
|
CG (with
motors listed) |
55.72” K1275, (4) H180 |
- |
- |
|
CG (with
motors listed) |
55.73” K700, (4) H210 |
46.1” K1275, (2) H97, (2) H180 (2) I-425, (2) I-435 |
98.1 |
|
CP
(Rocksim) |
79.3” |
58.9” |
123” |
|
Static
Margin |
5.9 |
4.25* |
6.0 |
|
* Static stability margin for booster is
representative of conditions prior to motor burn, and will improve before staging
(when the booster actually must fly on it’s own.) |
|||
Schedule:
Flight One:
The initial
plan was to fly the sustainer only in late June at Black
Rock in the Aero-Pac
event called Mudrock,
this would be my Level 2 certification flight (attempt was successful!). This flight used a central ground started
54mm K1275-R, and four air-started 29mm H180-Ws. Air-start timing sequence was set to start all 4 H180s at T+1.5s,
which lit them about .5s after burn-out of the central K.
Flight Two
(the reason for building this rocket):
The main
reason I started this plan is to fly the rocket with both parallel and
sequential staging, in the true spirit of the Tom Cloud Memorial Launch,
and the Aero-Pac
tradition and XPRS theme,
at XPRS-3 in
late September 2004 at Black
Rock. This flight will use 14
motors, 9 in the booster and 5 in the sustainer. This flight will burn 8330 Ns (about 63% M). And it will go like this:
Ground start
a central 54mm K1275-R;
Air start
two 38mm I435-Ts,
Air start
two 29mm H97-Js,
Air start
two 38mm I435-Ts;
Air start two
29mm H180-Ws; (Yes, that is RED Line, WHITE Lightning,
BLUE Thunder,
and BLACK Jack)
---- Stage
Separation ----
Air start
four 29mm H210-Rs;
Air start a
central 54mm K700-W.
Exact event
timing plan can be seen on this Timing Chart
Flight Three:
I designed
the booster and sustainer fin can motor mount airframe sections to be
interchangeable. I did this because I
want to fly the 9-motor fin can in single stage configuration also. Since that flight will be in season two
(2005), I wont plan the motor combination until later. But expect it to be the K1275 central again,
and probably (4) I435 & (4) H180.
Design
Documentation:
The initial
RockSim designs of this rocket: 2-D and 3-D views
Aft
Cross-sectional views: Sustainer Booster
Parts:
The PML parts order arrived
containing most of the stock for the project including the main nose cone,
phenolic tubes, centering rings and bulk plates, piston kits, and two sets of
custom cut G10 fins. The rest of the parts
had already arrived including: 12 nose cones from Ray Dunakin at HAKO Ballistics; 3
parachutes and two add-on dual channel igniter boards for my R-DAS from Bob
Fortune of Aerocon, and two PET2 Dual
channel timers from Missile Works. Already in my electronics stable are three
G-Wiz units, 2 MCs & one LC. After
the initial tube cutting session, my table was a little crowded, and looked
like this!
The
Building Process begins… On page two
