GoSlash27

Stoney3k, The designer is only awarded points for somebody else's flight. It is therefore in the designer's best interest to make a flyable spaceplane. If the plane fails due to pilot error, no worries. Another pilot should have success with it. If all the pilots crash it, it's obviously not a winning design. If all the pilots have good success with it, then clearly it's a solid design. Best, -Slashy

Claw, Excellent information! Do you happen to know the formulas by which these are derived? It'd be handy to be able to recreate these curves mathematically for engineering purposes. Best, -Slashy

SPA, For what it's worth, I don't use mods to calculate DV. If I read it right you have 1,378 units after your retroburn. That's 7.66 tonnes of fuel for the LV-N (units/180). If you know the mass of the ship in orbit (info tag) and the Isp of the engine (right click on the engine) then you can calculate the DV. DV= 9.81*Isp*ln(Ship mass/(ship mass-fuel mass)) I don't know what it's mass is in orbit, but it doesn't look very heavy. I think you could make Duna. Best, -Slashy

What Val said. Beyond having "enough" intake air, additional intakes add nothing but mass and drag. Most intakes are more than sufficient at 1 per engine. Best, -Slashy

Nothing. Most planes have sufficient yaw stability to obviate the need for active yaw control. Just bank it and the tail will keep it in line. Best, -Slashy

^ What Starhawk said. Mine actually has the fin locked. Best, -Slashy

Nich, I can't guarantee that this is correct. That's just what the math suggests based on the info I have. Please let us know if the AV-T1 makes a miracle- plane. Remember, nothing else can attach to those. You're limited by surface area. Best, -Slashy *edit* Also remember that the drag performance of wings is much better than fuselage sections (especially the Mk2) and clean design matters more than either of those.

^ I agree with all of this, which is why I only use SSTO spaceplanes for routine logistics flights to LKO. Transporting crew to orbit and back is a function you have to do fairly often. Ditto carrying fuel/ oxidizer and monoprop to orbit. Spaceplanes are good for these mundane jobs. Everything else, I use conventional lifters. Best, -Slashy

If the air density and gravity are the same, then spaceplanes should achieve the same performance as stock. RAPIERs can exceed 1500 m/sec even at very heavy loads. Turbojets can exceed 1100 when heavily loaded. Basically it's the same thing as building an SSTO spaceplane with an additional 2,200 m/sec DV. I'm thinkin' that's doable at a comparable payload fraction to conventional staged rockets. I have a 24t SSTO spaceplane that carries 8.6t of cargo to orbit in stock KSP; 36%. It weighs roughly 13t in orbit, so my back-of-the-envelope says it can hit that orbit with 3.8t payload. That's about 16%, which is in-line with staged lifters. Best, -Slashy

That's good stuff! -Slashy

sardia, I wouldn't know anything about that, sorry. I do have a list I've compiled from the data I mentioned: Area Cd Part 0.0858 0.0723 AV-T1 Winglet 0.536 0.0963 Big-S Wing Strake 0.153 0.213 Wing Strake 0.0280 0.220 Basic Fin 0.884 0.295 Swept Wings 0.184 0.337 Structural Wing Type D 0.363 0.338 Structural Wing Type A 2.22 0.409 Big-S Delta Wing 0.735 0.441 Delta Wing 0.735 0.441 Swept Wing Type A 0.363 0.443 Small Delta Wing 0.753 0.484 Swept Wing Type B 0.735 0.492 Structural Wing Type B 0.191 0.506 Wing Connector Type D 0.753 0.507 Wing Connector Type B 0.735 0.509 Structural Wing Type C 4.75 0.512 FAT-455 Aeroplane Main Wing 0.367 0.515 Wing Connector Type A 0.367 0.515 Wing Connector Type C 0.367 0.515 Wing Connector Type E This is strictly edge-on drag numbers. I don't have any source for the side-on values. I crunched these numbers with the lift values and came up with a heirarchy of wings for lift/ drag. Here they are in ascending order of load capacity and (mostly) descending order of efficiency: 1) AV-T1 winglet, 59.6. Estimated load capacity 3 tonnes per pair 2) Wing strake , 15.3. 4t 3) BigS strake, 19.4. 8t. Bonus: They carry 200 units of LF per pair. 4) Connector A 10.6. 16t. 5) SweptB, 6.2. 18t 6) BigS Delta, 5.5. 40t. Bonus: They carry 600 units of LF per pair. 7) Airliner wing, 3.2. 62t. Bonus: They carry 1,200 units of LF per pair.

For those interested in the parasail... I really just came up with it because I suck at VTOLs and wanted something that used primitive tech to get science from the rooftops in career mode.. I deploy the chute at the same time I start the engine. Throttle up and a little nose up and it takes off. I steer with the rudder and control climb rate with throttle. For final descent, I pitch up and adjust the throttle for glideslope (very steep and slow descent). Best, -Slashy

Technical stuff aside, that picture! - - - Updated - - - True, but it *did* work. The point is that if you have a low t/w you shouldn't look to reducing wing area or incidence to help reduce drag. You should look to go the other way. My most efficient designs at the moment work at higher t/w, but the original question was about low t/w spaceplanes. Best, -Slashy

Welp... The bad news is I dented the ship a bit (that'll buff out). The good news is I managed to save Val. The ship is acceptable, it was pilot error that did it in. I was overly- aggressive on the s- turns and lost too much speed too early. I wound up coming down on the West side of the mountains in the dark. Found what I thought to be a suitable landing area and set it down fine, but it had an abrupt change in slope that I didn't spot until it was too late. It rolled and disintegrated, but thankfully I was going slow enough to save Val and a few chunks of wreckage. It had enough to do the job. I'd recommend adding speedbrakes, solar panels, and maybe moving the ailerons inboard some. Final score +12 for kerbals delivered. -20 points for destroying the ship. -8. No kerbals were harmed in the filming of this catastrophe... Sorry! -Slashy

Well... the battery recharged when I docked, so that shouldn't be an issue. I had another 'senior moment'. I was waiting for an evening reentry window to maximize exposure for my solar panels Suppose I'd best get on with it...

Successfully docked. Made it with less than 2 units of electric charge. It was definitely an emergency condition! Still have plenty enough DV for deorbit, but I'm pretty scared to try it without the airbrakes... Best, -Slashy

Starhawk, It flies just fine. I established orbit without any fuss. I arrived in orbit late, but that allowed me to save a little on the transfer to intercept, so no worries there. But I *do* have a major worry in another department: This thing has no solar panels! I'm monitoring it for now and rationing power. Also, I must not have been quite as efficient on my launch. I have 100 m/sec to achieve the rendezvous. It should be enough. Best, -Slashy

Hint taken. I'm just making sure I've got the procedure down before I risk it. Is there anything you recommend I should do with the remaining fuel prior to reentry? Best, -Slashy

Starhawk, I concur with everything you've said. I had all the same issues when I tried it. Had I taken a couple test flights before submitting the design, I could've ironed all of it out. Nevertheless, it looks like you're atop the "pro pilot" leaderboard despite that. That'd give you like 16 points... *if* it counts. The Camacho is definitely not for the faint of heart in it's current condition. Now that you've flown it, I can issue recommendations: Enable roll control on the canards and transfer remaining fuel forward before reentry. Congratulations on handling the beast. It takes a good pilot. Best, -Slashy

Pecan, I've found that I can land fine in all biomes without needing the parachutes. The exception is KSC rooftops, which I work with a parasail. These are much easier for me to land precisely and cheaper/ easier to design. Best, -Slashy

sardia, It does matter which wings you use. Different wings have different "drag cube" values, lift ratings, and mass densities. Somebody posted the new drag values (not the same as the old config file numbers) but I don't recall where they were posted. I think they were also the edge- on "parasitic" values rather than the "induced" values that come with making lift. Best, -Slashy

Jouni, True, but even a Harrier design would be more mass efficient than stock KSP design because it's not carrying the mass of redundant engines. KSP VTOLs (at least the stock ones) are more like Yak-38 Forgers. Stoney3k, That's the part I struggle with; the engine spooling is so slow that they're difficult for me to manage in landing. That, coupled with the fact that I can't find a suitable role for them that I can't do more easily by other means keeps me from playing with them much. Best, -Slashy

It could also be that you have an excessively flimsy structure and/ or too powerful control surfaces. Both can cause an excessive control oscillation. Best, -Slashy

Heck, I'm not a semi- new player and VTOL planes are hard for me. Best, -Slashy

All, Val is correct about the benefit of adding incidence and also correct that the design I've shown here doesn't employ it. Geschosskopf is talking about the same thing I am; when dealing with low t/w, it's important to *not* jump to the conclusion that reducing wing area (or incidence) will help. Adding wing area or incidence can actually reduce drag. Here's a bigger one incorporating 3° incidence to further reduce drag: Best, -Slashy