regkoestoer

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About regkoestoer

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  1. hello I just finished the STS-1b with the same design I used in my previous post called "Extension Mk.2". All stock parts, Mechjeb installed, and BDarmory installed but not used. I built the fuel pod myself based on the pic on page 1 and it turned out around 40t (40.90t if I'm not mistaken). please kindly find the album in this link: http://imgur.com/a/eichK I used a full fuel load this time and added a couple of Kickback SRBs to help with the launch (even that only gave me barely enough delta-V). I didn't really expect this design to work as I haven't tweaked the CoM or wing inclination or anything (which are planned for Mk.3 btw, as per suggestions from this forum), but I just gave it a go for fun. Launch was OK, I used a steep angle. Turns out, at the very end of the booster stage burn the whole thing flipped backwards, and I basically detached the orbiter from an out-of control booster, so yeah we hit some small stuff. Orbiter is OK though, carry on. So I aimed a bit above 1000km orbit. I cut the throttle as we got something like 1200km. Then we circularized, which took a painful 6-minute long burn (with 3 NERVS). Turns out the orbit tolerance was just 100 m, so I made a few more adjustments. Settled at 1279km. Deployed the fuel pod (contents remain untouched and full). Then I start descending. But not altogether, I first went down to a stable orbit at 130km to make sure the reentry speed is OK at first go. Then we made the reentry run. I told old Jeb to keep holding prograde. We had some "turbulence" due to my personal meddling at the end of the reentry run but all is good, we recovered, without it we would've overshot the KSP again. So yeah, quite easy this time. I fired the engines a bit to add airspeed to make sure we reach the KSP. And we did. Landed on the old main runway.
  2. @53miner53 yes the CoM and CoL problem really bugs me lately. I simulated all conditions in the SPH (empty, fulltank, RCS full or not) to make sure the CoL always stays behind the CoM so it doesn't flip, but I think the "arrow flying backwards" thing is the one that got me @AeroGav ahh yes I never really considered L/D ratio in my shuttle designs (my design philosophy was: any brick with wings is a shuttle if we strap it on big enough boosters)....gotta try that inclined strakes trick...thanks for the enlightment! That's a really clean and clever design you have there. Btw, congrats on the STS-2a run! I never knew we could cram so much stuff in the cargo bay @Scabank whoaa...those fists are just....awesome. Mazinger-level awesome @StahnAileron one solution I found in the past is having 2 fuel tanks, one in front and one in the back, and then pump fuel around like submarine ballast tanks to modify CoM during reentry (or any other flight situation). For my more recent shuttle designs (with no ballast systems), I just had to stick to flying with very low AoA (<10 degrees, perhaps 5) during reentry
  3. Thanks for the feedback! “Tail Heavy” is the right word for this design. Even under load, the CG rarely moves forward beyond halfway of the length of this 44-ton craft. For STS-1a I tricked out the fuel loadout a bit so I only had a bit of fuel in the wing strakes and the other tanks were empty. So I moved the CG to the front slightly. Even then. it was just slightly ahead of the liquid fuel tank. The problem with CG so far in the back is that it needs a (very) steady hand during re-entry, any excessive AoA (usually above 10 deg) will flip the plane over, spin uncontrollably, and then it’ll fly backwards in atmosphere. I used a bunch of RCS thrusters to control the nose for that problem (barely). Actually the pitch control felt quite OK (I only used the inboard Elevons for pitch and the outboard ones for Roll, and that was OK so far) as long as we keep the AoA in control (i.e. don’t get into a spin). Maybe its because the CL is very close behind the CG, almost like super-maneuverable fighters. But you have a great point there with the Elevons on the front strakes. Does it mean they function kinda like Leading Edge Slats? Anyways I’ve added it to the “Extension Mk.2B” version and I’ll try it out tomorrow! Yes, the booster stage I used for this mission was kind of overkill (it can get the shuttle to LKO on its own, with fuel to spare). You’re right, for LKO missions I only need 1700 dV from the booster stage and then the craft has enough dV (3900) to circularize and everything. Next time I’ll try a more efficient launch with SRBs rigged for 1700 dV instead, as long as my TWR can carry me! (the 3 Nervs only makes 0.4 TWR so I hope it climbs)
  4. Hi, this is my first post! I saw this exciting thread and thought one of my old designs might be up for the challenge for STS-1a. It's called the Extension Mk.2. It has a simple traditional shuttle layout (nothing fancy yet). Originally, I made it for Duna missions, hence the nuke engines. album link is here: http://imgur.com/a/iuRNS Mods used: - MechJeb (for ascent guidance and delta-V calculations) - BD Weaponry is installed (but not used) - apart from that, the shuttle is stock The mission was fairly straight-forward. Ascent final inclination was 45 degrees and the craft was circularized at 200 km altitude (all using the launch vehicle). At that point the orbiter separates and we start to look for a de-orbit point. After that we did the de-orbit burn. I lost some control at the end of the long re-entry run and recovered, but we overshot the KSP a bit. Some teasers: So I landed at the island airstrip. I had to use the main engine a bit to avoid stalling on the approach. But it was all good and we landed. I parked the shuttle in the fighter squadron hangar. I think I can claim the Commander badge (landing at the island airstrip is ok, right?) Gonna do the next missions and perhaps also retry the STS-1a with weirder designs. I want that Skunkworks Badge!