Kerbodyne SSTO Division: Omnibus Thread

[Wanderfound]

What a lovely looking bit of work - can't wait to try it out! So this can obviously go to the Mun/Minmus from the runway - with or without an LKO refuel?

Can it get to, say, Duna/Eve? I'm assuming the lander couldn't handle Eve without parachutes or some such.

Does it fly like a Dairyman where you just pitch up to say 15 degrees and stay there, or more like the other planes where you level off at 20km and get up to mach 4.5 or so?

Nuke planes are a bit of a special case.

Start with a normal shallow climb, 5-25° depending on preference. Once you've maxed out your air-breathing height and speed, let the RAPIERs flick to oxidising and engage the nuke. Flatten out to about 5-10°. Watch your "time to apoapsis". As soon as it gets to a minute or so, kill the RAPIERs and fly on the nuke. Keep watching the T2A; flick the RAPIERs back on if it looks like it's going to hit zero, but shut them off again as soon as it stabilises. Aim to get your periapsis to at least 40 Km before the apoapsis cracks 70. Have a look at the fuel figures visible in the screenshots.

I haven't tested Ranger beyond LKO, but I'd expect it to do the Mun/Minmus easily without a refuel, and just about anywhere else with an orbital top-up. Do remember that it needs KAS strutting to work on reentry after a mission.

[Wingblaze]

As for the re-attachment: I need to look at the probes in detail. One personal pet peeve of mine is the number of small fiddly instruments. I have a small mod that I think is called Sensor Array (which I can't find out there any more) that puts all the science parts in one small disk in various diameters. You only have to find and click on one part to run your various tests, and it's easy to stack several into a ship without clicking on one vs another. I even hacked it to include a materials bay which wasn't in the original mod. My point being is that I'll end up modifying the probes to remove the materials bay, which might make them smaller and less prone to flop around.

Or not. In which case, explosions. 'nuff said.

[Wanderfound]

As for the re-attachment: I need to look at the probes in detail. One personal pet peeve of mine is the number of small fiddly instruments. I have a small mod that I think is called Sensor Array (which I can't find out there any more) that puts all the science parts in one small disk in various diameters. You only have to find and click on one part to run your various tests, and it's easy to stack several into a ship without clicking on one vs another. I even hacked it to include a materials bay which wasn't in the original mod. My point being is that I'll end up modifying the probes to remove the materials bay, which might make them smaller and less prone to flop around.

Or not. In which case, explosions. 'nuff said.

Normally, I would collect all of the science into an action group. You could easily do that by adding them to the door opening group.

The problem with an unstrutted lander is that it sags through the bottom of the cargo bay on reentry. A Materials Bay doesn't weigh much; that's why it's on top. You could probably lose the small fuel tank and change from a Jr to a regular clamp-a-tron. Still risky, though.

Edited September 25, 2014 by Wanderfound

[Wanderfound]

Strut-free extended-range compact-lander version of the Ranger at https://www.dropbox.com/s/nhq8hw5dcrhewqa/Kerbodyne%20Ranger%20XR.craft?dl=0

EDIT: nope, that one needs struts too. Unavoidable. I wonder if there's some sort of auto-clamp mod part out there?

Edited September 26, 2014 by Wanderfound

[Wingblaze]

Wow I see what you mean about the lander getting floppy.

[Wingblaze]

Yeah we need something like electromagnetic clamps or something. Or dual point docking ports. Or something.

[Jovus]

I wonder what would happen if you tweakscaled a clampotron sr?

You could also put a KAS magnet on the back end. Don't know if that'd work or not, though.

[Jovus]

Wanderfound, thanks a ton for the stuff you wrote up about aerodynamic analysis and building. A lot of it I knew or sort-of-knew already, but much of it was very helpful. I've already detected several changes I'd like to try in my designs and my design process.

Funnily enough, I disagree with you about the flaps. I find it very helpful to make my nose canards act as flaps, and then for final approach I put them on setting 1 or 2 to naturally flare the plane for landing. Using them at the same time as properly balanced spoilers can even raise the nose without causing you to gain altitude. (I'm aware this is exactly not conventional aeronautical wisdom.)

[Wanderfound]

Wanderfound, thanks a ton for the stuff you wrote up about aerodynamic analysis and building. A lot of it I knew or sort-of-knew already, but much of it was very helpful. I've already detected several changes I'd like to try in my designs and my design process.

Funnily enough, I disagree with you about the flaps. I find it very helpful to make my nose canards act as flaps, and then for final approach I put them on setting 1 or 2 to naturally flare the plane for landing. Using them at the same time as properly balanced spoilers can even raise the nose without causing you to gain altitude. (I'm aware this is exactly not conventional aeronautical wisdom.)

There will inevitably be an element of personal taste involved in any advice given.

I find flaps very handy on large or slow cargo stuff, but I don't like planes pitching unless I tell them to. I find that having a pitch set by flaps or spoilers gets troublesome when you want to suddenly change that pitch.

If I want a set pitch on approach, I'll trim up and counter the climb with spoilers. For slow climb, level and flaps; slow descent, level and spoilers; very slow descent, level and flaps and spoilers. I wish you could easily set spoiler level in flight like you do with flaps, but you can approximate it by counter-flaps.

I always try to keep my flaps and spoilers balanced; those combinations get too messy if they aren't. It helps that I'm building more mid-wing than delta stuff lately; no need to balance canards vs elevators.

[Wanderfound]

I wonder what would happen if you tweakscaled a clampotron sr?

You could also put a KAS magnet on the back end. Don't know if that'd work or not, though.

Standard Clamp-a-trons and splitting the lander into two dockable sections appears to work. The magnet idea is worth looking into, though.

The other option would be to just run a Module Manager script that beefed up the rigidity of Clamp-a-trons. Make the strutting assumed.

Edited September 27, 2014 by Wanderfound

[Jovus]

I'm looking forward to getting to see a copy of the Brutus. It looks like one beast of a plane.

[Wanderfound]

I'm looking forward to getting to see a copy of the Brutus. It looks like one beast of a plane.

It's fairly easy to tweak the Brutus to carry one of the Ranger landers along with a Microbus (http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread?p=1431743&viewfull=1#post1431743).

Put that rig together and you can go anywhere.

[Wingblaze]

Something odd is happening. The flaps and spoiler on my Dairyman TSP aren't working - action groups are gone and I can't seem to put them back - no actions showing for those parts. I just re-dl'd the file and still not right

[Wanderfound]

Action groups disappearing during craft sharing is a known bug.

Inability to re-establish them is a bigger thing, though. Search your Gamedata folder for extra copies of ModuleManager and delete all but the latest. Kerbpaint in particular has an archaic copy buried in a subfolder that is known to cause problems with the FAR-derived control surface tweakable options.

[Wingblaze]

Seems to have fixed it, thank you. No wonder everything is flying for crap

[Wanderfound]

A special last-of-the-old-breed model, soon to be rendered obsolete.

From our own in-house tuning shop Kerbodyne Special Vehicles, comes the new KSV Benchmark GTHO. Gave it a body kit, swapped out the central turbojet for a third RAPIER, replaced the ramscoops with shock cones and nacelles and lengthened, streamlined and upgraded the fuselage.

Zoomy enough to race to orbital altitude and speed, flip retrograde and immediately scrub off the entirety of its orbital velocity, with fuel remaining to run the jets on the descent. Runway to orbit to runway without ever completing an orbit or making a turn in atmosphere, in under 20 minutes.

https://www.dropbox.com/s/qv9v27spfk...THO.craft?dl=0

Needs SP+.

Edited September 30, 2014 by Wanderfound

[Wingblaze]

So it's for the runway-to-orbit-to-runway challenge

Still struggling with probe deployments. What good is a cargo bay when it doesn't hold cargo? Sigh.

[Wanderfound]

What's giving the trouble? Make sure that nothing protrudes from the bottom of the bay, strut well and pop 'em out as smooth as you can.

I doubt it has the grunt to beat the Goblin, but it'll run it close.

Edited September 30, 2014 by Wanderfound

[Wingblaze]

I have parts getting stuck in the bottom of the bay it seems. (Not your probes - I was making something smaller to fit in the Dairyman and land and leave behind on the Mun.)

I need to start playing with the Ranger and expand my reach.

[Wanderfound]

I have parts getting stuck in the bottom of the bay it seems. (Not your probes - I was making something smaller to fit in the Dairyman and land and leave behind on the Mun.)

I need to start playing with the Ranger and expand my reach.

That's one I learnt from experience: you can afford to poke through the top of the bay a bit, but not the bottom, especially with things like lander legs. It's worth fiddling with the mounting points; often with SP+ bits, there's more than one spot to mount to, and the higher one may let you clear the bay floor. And there's always the old cubic octagonal instant mounting point trick.

The Ranger​'s lander has that skinny Oskar-B base for a reason: it's the only way to fit lander legs into an SP+ bay. You can go as long as you want within a 1.25m radius, but it really does need to be within the radius.

At least it seems that you haven't yet knocked any solar panels off while leaving the bay...

It's not up yet, but I've got a version of Ranger in the works that doesn't require any strutting. Split the lander into two bits, each small enough for a docking port to hold stable.

Edited September 30, 2014 by Wanderfound

[Wanderfound]

PS: if you're unsure, mount the plane upside down on some girders, take it to the runway and drop the probe on the deck. You'll probably lose the probe, but it may be worth the cost to avoid a wasted flight.

[davidpsummers]

How you calculate mach in m/s?

[Wanderfound]

Mach varies with pressure, so there isn't a simple all-altitude conversion. Roughly speaking though, Mach 1 is about 350m/s.

Both FAR and Kerbal Flight Data will give you your speed in Mach numbers.

To go to space, you want to get fast before you light the rockets. 1,000m/s is a bare minimum, 1,500m/s is better, 2,000m/s is excellent.

Edited October 2, 2014 by Wanderfound

[davidpsummers]

My current test plane is this....

I have gotten it up a ~65 km apogee (and maybe 1/10 the fuel needed to circularize) and decided it just wasn't quite good enough. However, reading the comments here makes me wonder if I shouldn't improve my piloting and see what I can do with this one (It probably still won't make, but I'll have a better idea where I stand) before designing an improved plane.

I've been able so, so far, to get maybe 1,100 m/s at ~22,000 meters. Should this plane have more in it?

[Wanderfound]

99% of my flying is with FAR, and it looks you're using stock aero, so BYO grain of salt. I started spaceplaning in stock before I switched to FAR, but that was some time ago. However:

By the looks of it, the setup there is a central RAPIER flanked by turbos, yes? The plane could use a touch of polishing (ditch at least one ASAS unit, to start with) but it looks as if it should be orbit-capable.

The first bit of advice would be to turn off the automatic mode-switching on the RAPIER and set an action group to toggle modes instead. You don't want it to start burning oxidiser until the last possible moment. Once the air runs low, shut down the lateral engines and run on the central one alone (thereby dropping your intake air requirement by 2/3rds, as well as avoiding all chance of an asymmetric flameout). Once that one starts to choke, gradually throttle down to extend it further. A single-turbojet basic plane can get over 2,000m/s and 35,000m altitude in stock aero if flown right. Your plane above should easily manage 30,000m and 1,500m/s.

You'd be better with a 1 turbo / 2 RAPIER arrangement; that way, you can leave the central turbo running in conjunction with the RAPIERs during final ascent. On your current setup, trying to do that would be a near-guaranteed flameout-induced spin.

Have a play with the stock aero version of the Benchmark: https://www.dropbox.com/s/lbnz9s8k9h7gwgb/Kerbodyne%20Benchmark%20StockAir.craft?dl=0

That one can certainly reach orbit with ease. If you struggle with the Benchmark, then yeah: you need to work on your piloting. Make sure to check the action groups before you go; none of my planes are designed to use staging.

Have you read through the piloting guide in the second post of this thread?

Edited October 2, 2014 by Wanderfound