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Ex Model Rocketeer from the 70s


SRV Ron

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As the title states, I used to fly model rockets and developed a process called ducted staging to allow scale multistage rockets to reliability stage up to 10 inches from each booster engine. Successfully launched a scale 4 stage design using Estes D engines that ended up two miles upwind.

In KSP, my first Kerbal rockets are based upon such designs starting with a single stage sub orbiter for flight testing. (Similar to the old Mercury program.) The Redstone design shows the need for aerodynamic stability. In model rocket terms, as long as the center of pressure is behind the center of mass, the rocket will fly straight up while experiencing atmospheric drag. A plain set of static fins placed as far to the base as possible are sufficient for that design.

The current two stage design, now with the Redstone upper stage modified with a low powered third stage, needed steerable fins on its booster to hold on course. Also, a set of braces were added to stabilize the long rocket from wobbling. Once cleared of the atmosphere, flight becomes stable. That simple design has placed its Kerbal astronaut into orbit with a partial burn of the second stage. With a full burn, it will reach an intercept with both Kerbal moons. The third stage retains all fuel for lunar orbit insertion and a safe return using an aiming point of about 15,000 meters in the atmosphere. That is good for a reentry slowdown that holds G forces down to about 5Gs. Like Apollo, the ideal launch should aim for that booster to crash into the moon so it doesn't become a future hazard for later flights.

I will be doing more experimenting with that rocket to learn more of orbital, lunar insertion, and how things work. Then' I will start adding more boosters to extend its range for interplanetary flight.

The nephew, who loved the old Amiga Solar System explorer program, will probably get hooked tonight. He downloaded the beta last night.

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My Redstone experiment that actually made low Kerbal orbit, over 100,000 meters;

Two stage rocket of 18 parts

1. Pod MK-1

2. MK-16 parachute

3. TR-18 Stack Decoupler

4. Advanced SAS Module. (Not sure if I could do without.)

5. F1-T800 fuel tank

6. LV-909 engine on model 1, LV-T45 engine on model 2. the 909 is weak on thrust for getting in orbit but did work. The T45 you have to throttle back to retain enough fuel for a reentry burn.

7. TR-18 Stack Decoupler

8. two F1-T800 fuel tanks stacked

9. LV T30 engine

10. Four Delta Deluxe Winglets mounted as low as possible.

11. Launch stabilizers just to be safe.

My flight experience with that design; (only one abort caused by not activating stability right away.) Both rockets need to activate stability during the launch or they would go off course after a short time. However, the fins stabilized things so much at 10,000+ meters as to make the gravity turn difficult. Second stage is fired to get to apogee above 100,000 meters, then shut down to save fuel till I reach apogee for the circular burn. The larger engine version needed to burn at reduced power for the orbital insertion. The small second stage engine one may be more efficient if one gets the insertion path right after booster burnout since it lacks the power to overcome gravity at separation.

Both rockets flew successfully, made orbit with sufficient fuel left to drop para gee to 15,000 meters with some to spare, and only subjected Jeb to a 2.7 G reentry and safe landing. (I popped the cute at 10,000 meters.)

Now, it is time to play with other designs for deep space flight.

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Added a booster stage using an adapter, large stacked tanks, and big engine. Bracing and adapter separator added. Still a bit wobbly mostly from the SAS and effects of the lower atmosphere. Have to be careful staging to avoid damaging the upper stage during ignition. Otherwise, the second stage goes out of control. Solution to save Jeb, shut it down, activate third stage and either orbit or return to Kerbal. The first two stages put me into a loop for encounter with Mum and a small burn of third stage to the second moon. However, a close encounter with Mum on the return loop towards Kerbal kicked me into escape velocity. At least, the third stage had a full tank for returning as I was now heading for a close encounter with the first outer planet.

Interesting game once I learn how to use the tools for insertion into orbit of those moons or one of the nearby planets with the present design. Then, strap on boosters for even more range.

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