Iskierka

SF6 wouldn\'t give nearly those values of a (= speed of sound), but a reduced mach 1 would be a good idea for gameplay. a in pure SF6 is less than 150 m/s. As for atmospheric scale, an open search of all forums for 'scale height' by HarvesteR turned up this very early post: It seems I was correct that the scale height had been reduced when the atmosphere was extended to 69 km, but it had been changed to 5 km, from 6.8 km. 5 km is consistent with what has been stated in other official posts and close to consistent with the data gathered in the other thread, which definitely has the potential to have slight errors.

This is actually getting towards the high end of what a single stock stage is capable of, since lift-off is required; it\'s quite likely this would be easier with a two-stage, though three stage would be excessive.

The /photos/ section of dropbox can\'t be hotlinked. Upload to /public/

Image does not work. Also, the only way to create an 'aircraft' with stock parts at the moment is a pile of winglets built around the least mass you can make the fuselage. And once you\'re already going for a pile of winglets you may as well make a magical space turbine, which is silly. Also, at least one part of the challenge is broken, which is to fly over lakes at under 1200 m: the highest mountain found on Kerbin is only 900 m, so there is no agility required whatsoever.

This is very much possible, in theory, and similar to the Roche limit, which is an alternative that defines how close an orbiting body can get to its parent before its parent\'s gravity is stronger than its own at the surface. At this point, assuming no internal material strength to hold it down, the body will break apart. Same thing for this idea; the body could be spinning this fast, and it would survive up to that speed. Beyond that speed, unless there is material strength to come under tension and hold the surface down, it will start to break apart.

Mods almost entirely. The ones with good balance are, if anything, worse than stock in most measures of performance, but the values for the stock parts are unrealistic enough that it actually becomes easier to launch with theoretically underpowered mods. Ofc, we then have the occasional person flaming a realistic mod for being unrealistic just because it\'s easier. Even if it is, in fact, worse than half stock performance. At least there\'s very few of these guys, and most people doing it stock are doing so because it\'s a consistent standard.

Kreuger flaps are entirely different, used for delaying stall. Flaperons are the name for combined flaps and ailerons, again completely different. What he\'s suggesting is a rare design that works a lot better in KSP than IRL, but there are aircraft that have similar things. Probably the best example is the Sukhoi T-50, though in this case they\'re more for engine management and stall delay than control: You can see at the leading edge wing root, the wing appears to be separated and pointed down. This is what he means by an 'in-line canard'; a forward control surface that is part of the main wing. Granted, those and the ones on the outer wing -are- actually kreuger flaps, which -do- behave differently, but this shows the idea of the in-line canard best.

On Earth, there is still measurable atmosphere at 10,000 km. Are you going to claim that the ISS, at 300-500 km, is in the lower atmosphere? The definition of space is the point where, ignoring coriolis effects, you need to go faster than orbital velocity to maintain enough lift to fly. Hence at that point, you\'re in orbit, not flying. On Earth, this is 100 km. Scaled for Kerbin\'s atmosphere and orbital velocity, this is around 30 km. The atmospheric gauge is a log scale - the atmosphere was long ago confirmed as logarithmic with altitude*, and you\'ll notice that with altitude, the atmospheric gauge is linear. Hence, logarithmic with density/pressure. See above for how the space definition works and gets scaled on Kerbin. * For reference, scale height is 5 km, whereas Earth\'s scale height varies between 8 and 6km. Taking a lower-atmosphere average of 7.5 km, atmospheric density on Kerbin for a given altitude is equal to that 50% higher on Earth.

Space is defined as above the Von Karman line, which is 100 km on Earth. When scaled for Kerbin, this comes down to around 30 km. Your record was taken 9 km into space.

Only L4 and L5 are easy to station-keep. L3 maybe. L2 and L1, quite difficult, you\'re probably better off with two sats in low orbit at either end, making sure at least one can communicate at all times.

Kerbin\'s atmosphere follows said exponential curve from surface to edge, and as I recall HarvesteR stated the scale height was 5 km, though I do also recall a more recent comment that might have changed the scale slightly (4.75 km comes to mind). Quite a bit of this data has had developer confirmation long ago, though it\'s fun to see the experiments people come up with to determine them.

Yeah, balancing an aircraft to launch, level out, and maintain its launch altitude is 'kinda hard' to say the least. This goes for a second best and has a design which will launch, then seek out and fly at a pre-defined altitude and speed (with mine, 8.5 km 191 m/s.) Tosh\'s rebalance apparently has gone for 2.5 km and 90 m/s. So, it\'ll only fly straight and level from launch if launched from that point. And heh, I did half-suspect there may be stability issues with default C7 parts ... I\'m really not sure what part I\'d choose to have. I mainly wanted to try make this fly for the fun of it Can I get back to you on that?

Sure, go ahead, though they\'re fairly minor alterations.

That\'s interesting, what speeds are you launching at and how quickly are you firing the drone\'s engine? Launched quickly I could see the possibility of backflips.

Ah yes, ofc. I was thinking the other way; if the plane pitches up with no other changes, the lift will encourage it down. I wasn\'t considering if velocity and nothing else changed. I\'m not sure what\'s providing the former stabilisation mode now, since it\'s necessary to avoid losing control completely, but I\'d probably be able to find something if I tried to construct stability equations for it. Only first year and first semester so far

Aerospace Engineering at University of Manchester. First semester was flight, including a topic covering stability and control, so yeah. As noted in my addition to that post, the incidence is probably wrong for perfect stability - though it might take quite some figuring out to re-balance other parameters to make it fly well again, so it\'s probably best to leave it as-is, since it\'s stable and flies like a (rocket propelled) arrow already.

I was mainly trying some things learned from my first semester at uni, regarding aircraft stability and control. In short, what\'s stabilising the drone is the incidence I\'ve given the tails - they\'re angled slightly down now, so as alpha alters, the centre of lift moves back and forth, which means that there is a particular angle of attack the drone wants to settle at. I don\'t think this is strictly necessary, but even a slight change in alpha causes quite a significant restoring moment, making it a very effective correction factor. EDIT: Actually, thinking about this more, I think I\'ve gotten confused, I should\'ve used opposite incidence to what I did in order to stabilise the drone. I\'m not sure why the lift doesn\'t completely destabilise because of this, though following points still apply. In addition to this, wings are very near zero drag (when at zero alpha in KSP, they -are- zero drag). This means the high-mounted tails provide almost no drag to cause a pitch-back, but do add to the centre of gravity, moving it above the main body. Since the main drag is then from the main body, drag causes a pitch-down moment, which increases with velocity. With the way the engine is set up, the thrust is almost exactly opposite to drag, but with no proportionality to velocity, meaning there is a balanced velocity where D = T. Since drag is also proportional to air density, it goes faster at higher altitudes. So, after some complex stability interactions, what happens is high lift causes it to ascend to a point where air density is such that, when D=T, lift = weight, thus resulting in a stable vehicle. I think what some designs also suffered from was a problem of thrust being greater than weight, which enabled them to pitch all the way over and loop. With a mass just over 0.6, and a thrust of only 2, this thing only has a TWR of around 0.3, meaning instead of looping, it decides to power into the air, looking for its balance altitude.

Fair enough, I would\'ve had a launch photo but as stated, didn\'t expect success. On a retry, launch: Hopefully the runway counts. As far as has been flown, the behaviour is the same. Should be approaching 8 km shortly after the 10 minute mark, and stabilising around 15 minutes. I\'m attaching a zip of the drone with adjusted configs (though I haven\'t cleaned them up, so there\'s some mess from trying to create attachment nodes. Because there are now left and right tail pieces, and the drone has been altered for mounting above the plane, testing in a different design will require complete (Yes, complete, don\'t try get away with half) reconstruction. I suspect the launch aircraft would be able to keep up with the drone, but it may suffer from lack-of-fuel problems prior to drone burnout in default C7 configs. It\'s also a work in progress and joystick problems make it difficult to tune out issues. Requires: attached drone, C7 (original and remake), tiberdyne shuttle launch system.

12 seconds to burnout. Just in case anyone was doubting. Unfortunately, the drone seems to be much less aerodynamic than the plane, and didn\'t waste time dropping behind after burnout. This unfortunately means impact point or distance cannot be determined. We can offer, however, a final shot of the drone being left behind, an image of an estimated impact point based on last known trajectory, and an estimate of 500-520 km range launched from low altitude. On a more useful note; I think this set-up for the drone should be quite balanced, and will probably have minimal dependence on launch conditions. I expect it to be possible to adjust final flight conditions by varying throttle, though I don\'t know how much, beyond that a thrust of 7 from low altitude will begin cartwheeling uselessly. (I think this one might be more useful launched at altitude and speed)

Damn, unlucky with that collision. I\'ll PM you the configs for the drone, craft for the aircraft, and my C7 configs (I don\'t use stock and I doubt this plane could match the drone\'s pace otherwise), though it might not be today, as I should leave soon-ish and would have to tidy up a little. As a further update on the drone\'s progress, it appears to be oscillating between just over 8.5 km and 8.4 km, and is still going after 45 mins (5 mins remain) at a strong ~191 m/s. Ground distance covered by the chase plane is currently around 450 km. Going by the roleplay political map, we\'re just crossing the north coast of Pedestrania, and will probably burnout not far from Forseti. Predicted impact zone is somewhere near the border of these countries.

Launch conditions were not accurately taken, due to it not being expected this configuration would work so well, but to estimate: 80 m/s, 400 m altitude, less than 10 degrees above horizon. As for config, I\'ll look at cleaning up the mess I made once this flight is completed, but the changes I made were: Reconfigured drone to be overhead mount, which removed problem of drone hitting launch vehicle. Created attachment nodes for forward wings for consistent placement. Tailfins were split into left/right pieces and given very slight inclination, and placed so the leading edge was touching the front of the flat mounting area for them. Throttle was reduced to 2, and I think that should be all changes. No craft editing, though constant roll tendencies make me want to look at the craft for the aircraft itself ...

Status update: the drone appears to be level at 8.3 km altitude and 155 m/s velocity after 15 mins flight. (I was paused for long periods) At this point the distance travelled is at least 90 km, most likely over 100, but an accurate figure is difficult due to erratic flying from the chase plane. Hopefully the drone doesn\'t outlast the chase and burnout can be observed.

The plane-dependent performance might instead be due to each competitor assembling their drone with marginal differences in positioning of parts. EDIT: I\'d thought this launch would be a dud, seeing its steep and slow climb, but I decided to let it fly for a bit and it seems to be levelling out around 5 km and 90 m/s. I\'ll have to watch it closer and see how it goes.

This was noticed shortly after reporting, further tests have been more careful to stay within line of sight. Also, the plan hasn\'t been for seeing where, it was just to see how long it endured. I\'ve made some progress on figuring out how to trim the drone to fly far, but implementing the design is tricky. Best results so far are with minor modifications of default settings, but are not self-sustaining (Within the bounds of launch conditions tested). My testing ends here for now, with one drone that flies at only ~50 m/s, and very insistently upwards, but is following a stable path.

Currently conducting tests here with minimal design modification. Currently only thrust vector and attach conditions have been modified, the latter allowing an overhead mounting, which results in the drone lifting itself clear of the parent vehicle unassisted by jettison mechanism, allowing much more stable launch. Initial tests are promising, though visual contact with current best was lost due to pilot/control error roughly two minutes after launch. Radio signals imply vehicle is still airborne after more than five minutes of flight, with an estimated cruise velocity of 120-160 m/s, giving an estimated range of 40 km or more. Report shall be updated once ground impact is confirmed, hoped to occur roughly 45 minutes from now, after burnout.