Kerbodyne SSTO Division: Omnibus Thread

[Wanderfound]

I will do some screenies tomorrow.

Wgat is ur setting with Deadly and Far? original or changed something?

The most recent changes to FAR (improved skin drag) have made DRE rather pointless unless you mess around with the back end settings to crank up the difficulty a great deal. Even when using DRE's "hard" setting, craft tend to slow down to safe speeds long before reentry heating becomes an issue.

It's not that there's anything wrong with either mod, it's just that the combination of realistic drag with Kerbin's low orbital speed makes reentry non-threatening unless you heavily modify things. So, for now, I've given up on DRE. Fortunately, there will be stock reentry heating in the soon-to-be-released KSP 1.0.

[eddiew]

...Would you like to get to orbit in the most overcomplicated and inefficient way possible?...

Efficiency is boring - if it wasn't, we'd just use rockets and save hours of game time to get the same stuff into orbit

[Nowater]

Ok, 1s after this, it starts to tumble...its at 23000, i dont get the speed over 3.36, no matter how or i am doing something horrible wrong

23000 by No_Water, on Flickr

Edited January 30, 2015 by Nowater

[Wanderfound]

Does the instability begin with yaw, roll, pitch, or some combination of those? In that image, it looks like you might not have the autopilot heading control engaged; I'm not sure if SSAS is holding your heading and bank angle for you or not. I'm not too familiar with the SSAS and autopilot modes of KPA; I normally use it just as a PID tuner on stock SAS.

There's nothing obviously wrong there, but as a first diagnostic step:

Turn off the vertical control autopilot and fly manually. In KPA, switch the SAS to "stock SAS" mode instead of SSAS, make sure the SAS is turned on (just the T-key toggle as usual) and use the PID tuner to cut all of the kp values to 1/3 default (i.e. 5000/3000/5000) and lower all of the scalar values to 1/2 default (500). Give that a try and let me know if the problem reoccurs.

[Nowater]

The heading control is on and functions exactly up to this point.

I will give the normal SAS a try. PID is exactly set to 5000/3000/5000 and scalar to 500

If i switch to the normal SAS the heading control of the the Pilot is paused. How do u hold the heading?

The instability sdtarts with yaw.

thanks

Mike

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Aaaah with normal SAS and Pilot its way better, 27k no problem, but then i messed it up...need some training, the controls are horrible. Any recommendations for a addon which shows me climb rate etc...like a HUd? What do you use for this?

Edited January 30, 2015 by Nowater

[Wanderfound]

Kerbal Flight Data and Kerbal Flight Indicators, both by DaMichel. Highly recommended.

As for climb rate: the stock game provides a Vertical Speed Indicator dial at the top of your screen, just to the right of the altimeter.

[Nowater]

Danke! (Thank you)

Orbit by No_Water, on Flickr

Do you know, how the satellites will get recognized inside the bay from a contract. Because i have them in the ship, it thinks its not unmanned...

Edited January 31, 2015 by Nowater

[blowfish]

Do you know, how the satellites will get recognized inside the bay from a contract. Because i have them in the ship, it thinks its not unmanned...

It checks that you have a probe core and an antenna. It doesn't care what else is on the ship.

[Nowater]

Hmm no,

i have a Satelitte as Cargo with probe etc...

It is notr recognized. If i EVA the Kerbal, it will be recognized (Switchin). If i go inside the Spaceplane again...not recognized

[blowfish]

Well maybe not then...

[Einarr]

I would think it would recognize the payload once it has been deployed (released from the bay).

[Wanderfound]

A new build tutorial: part 1 of 3.

[eddiew]

i have a Satelitte as Cargo with probe etc... It is notr recognized. If i EVA the Kerbal, it will be recognized (Switchin). If i go inside the Spaceplane again...not recognized

Your 'cargo' is still attached - which means it is considered part of the plane, which not unmanned. Just detach the satellite and switch to it, then it'll register for the contract.

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A new build tutorial: part 1 of 3.

Ooo, nice, one for later, cheers Wander Any chance of covering an MK3 build in the future? Even with B9 parts, mine all end up sluggish and awkward... :/

[WhiteKnuckle]

Any chance of covering an MK3 build in the future? Even with B9 parts, mine all end up sluggish and awkward... :/

I'll second this.

I've made a Mk3 cargo plane that flies pretty well actually, for what it is. And using B9 parts I can make a Mk3 spaceplane that can take an orange tank to orbit no problem. But in stock, well, I can get an orange tank to orbit... I just can't come home afterwards.

[Wanderfound]

I'd prefer to do a Mk3 vid after they release the upcoming larger gear and wings, but if 1.0 takes too long to arrive I might get in earlier.

[Einarr]

I take it you don't use the Simulation mode of the FAR window in the design process, Wanderfound? I'm also eagerly awaiting the next 2 installments of your build video as your solutions may be helpful in my own designs.

[Wanderfound]

Ibis build tutorial, part 2 of 3:

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I take it you don't use the Simulation mode of the FAR window in the design process, Wanderfound? I'm also eagerly awaiting the next 2 installments of your build video as your solutions may be helpful in my own designs.

I never did figure out how to use the Simulation mode. If anybody knows how it works, please do tell.

[Wanderfound]

Ibis tutorial, part 3 of 3:

[eddiew]

Can't deny the appeal of a quad-rapier bird when you just want to get to orbit without fussing around too much For the VTOL manoeuvres, wondering if it might be easier to control from the docking port, since then you'll be more likely to see your prograde marker?

You suggested in the last video that you could have swapped two rapiers for jet engines. Whenever I try this, the jets always fizzle out at a lower altitude than a rapier would have, even when the air intake looks fine, and at lower altitudes they like to overheat and make me back off the throttle. Not sure what I'm doing wrong, but I consistently get better results with all rapiers - although I usually kick the outer pair to rocket mode while the inners are still breathing, just to get as much from them as possible.

And a request for a future video, if it takes your fancy! Something that can land on Mun, ideally doing the whole round trip without a refuel. Following your design tutorials and advice has gotten me to the point I can confidently make stuff that gets to space and comes home, but landing in a vacuum is intimidating for a winged vehicle. Maybe some LV-909s (or smaller) in the VTOL bay?

[Wanderfound]

RAPIERs auto-throttle to delay flameout; turbojets don't. You need to throttle down or thrust limit them to keep them running at extreme altitude.

I find Vernors adequate for low-grav VTOL (easy on Minmus, tricky but doable on the Mun). The key is to use your main engine to bring yourself to a dead stop 50-100m off the deck, then quickly flip over to be level and in line with any residual lateral motion and VTOL the last little bit. A flat target helps; again, easy on Minmus, tricky on the Mun.

For more intense low-G VTOL, I'd be inclined to line a bomb bay with the little Rockomax radial engines. I tend to find vertically-oriented VTOL control a bit disorienting when moving laterally, but it works well for landers.

[eddiew]

Yeah, I'm aware of the auto-throttle, but even with nursing the jets I just can't seem to keep them litat any level of usefulness. Starting to wonder if I've got something that's auto-throttling them; maybe MechJeb's prevent overheat option is getting in my way.

Alas, I still don't think I have vernors as yet (my 0.90 playthrough is kinda slow), which may be one reason I struggle to keep my birds stable in that 25-35km zone. Need to focus my research towards them and have a go with those radial engines as VTOL... rather taken with the idea of packing a little rover into a bomb bay

[WhiteKnuckle]

eddiew, if you're playing with FAR then the turbojets are going to run out of power at just over 1km/s. And at least in my experience they won't overheat. Next time try leaving them at max throttle and right click one to see it's power output. At around 700m/s they start to make max power, and they also start to overheat, but as they climb closer to 1km/s the power output will drop, and they will stop overheating. By 1.1km/s they're making essentially zero power and it's time to turn them off, even if you still have intake air.

And if you want to try a VTOL with the radial Rockomax engines, I've got a few, just check out the link in my sig.

Wanderfound, great videos as always. I'm going to have to try that trick with the canard pitch settings. For someone that says they suck at flying VTOLs you seemed to do just fine. One trick though, you use a lot of fuel using the vernors to arrest your climb rate by just thrusting downwards. On a craft like that one with a narrow wingspan, I'd be more inclined to do a quick barrel roll, or just a quick roll 90* one way then 90* back the other way. This spills off a lot of your vertical thrust without having to adjust throttle or use a ton of fuel with the vernors.

I'm wondering, does that thing stay balanced when you're low on fuel? And if so does it require a fuel balancing mod or is there just some fancy fuel line routing that I didn't see going on?

[Behemoth1702]

Do you have a bizarre attachment to retro-80's space tech? Would you like to get to orbit in the most overcomplicated and inefficient way possible?

Then the Kerbodyne Titan Shuttle is just what you're looking for...

http://i1378.photobucket.com/albums/ah120/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Titan%20Shuttle/screenshot80_zpsvelnhf5l_1_1.jpg

http://i1378.photobucket.com/albums/ah120/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Titan%20Shuttle/screenshot93_zpshi4ay9e2_1.jpg

http://i1378.photobucket.com/albums/ah120/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Titan%20Shuttle/screenshot100_zpstgkc6evh.jpg

Annotated test flight at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Titan%20Shuttle/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Beta/Kerbodyne%20Showroom/Titan%20Shuttle

Craft file at https://www.dropbox.com/s/jnpfrcb5rdeqn6l/Kerbodyne%20Titan%20Shuttle.craft?dl=0

(note: this does require some piloting skill to fly. Not recommended for serious use; built it just to prove I can)

Haha, thank you!

Tried this one today, it's hard to fiddle with all the action groups but fun! Thanks!

[Wanderfound]

I'm wondering, does that thing stay balanced when you're low on fuel? And if so does it require a fuel balancing mod or is there just some fancy fuel line routing that I didn't see going on?

Haven't tested it that far, but it should be okay. The fuel lines are set to keep it fairly balanced, and the jets can gimbal enough to compensate for minor disturbances.

[lordcirth]

Hi Wanderfound, thanks so much for all the great spaceplane ideas. I have a problem though: I downloaded the Kerbodyne Initiale, as I am in career mode, but when I launch it, it often pulls sharply to the right on the runway. I can keep it on course with manual steering but it's tricky to get to takeoff speed without tipping and smashing a wing.

Clearly this wasn't happening for you when you made it, so I'm wondering if a new FAR version changed something? I am in career mode, and only have basic action groups, which will change the jet>rocket transition, but shouldn't change runway performance. I am using the Level 2 Runway in career mode, but I've tried the same .craft in Sandbox and it has the same problem. If I can get it off the runway with decent speed, it flies ok, but this is rare. Planes I've made recently, although they have plenty of other problems, don't yaw so hard on the runway. I know that normally a pull to the side would mean too much weight on landing gear, but wouldn't that pull in random directions? Also this plane isn't too heavy. Reseating the landing gear with angle snap on doesn't change anything, so it's certainly on vertically.

I just tried putting a T800 in the cargo bay in Sandbox. It pulls to the left as it starts, then at 50m/s it starts pulling right again. This is very confusing behaviour.

Also, possibly unrelated, most planes I make get very unstable around 20km-25km even though their stability derivatives at similar altitude and speed show green. They change attitude with controls, but this seems to have no effect on their course until I pitch so high that they suddenly flip and explode. Am I just piloting wrong? The few times I've been able to try the Initiale at 20km it worked fairly well.

In both scenarios, I'm usually using FAR's flight assists, but I have tried all combinations of SAS, FAR, and no assist. I haven't tweaked SAS.