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Basic VTOL Challenge -- Let's learn more about VTOLS

codepants
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codepants

codepants

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skycrane_mk_VI.jpg

First post -- woohoo! Hope it goes to good use.

Anyways, since building my first successful space plane (and getting really good at building planes in general -- only took 160-some playing hours) I've developed a fascination with VTOLs. There have been a few VTOL challenges (most similar one here) but they can become very frustrating very quickly. I wanted to design one that was possible, and possibly even easy. You get vastly more points the more you challenge yourself, however.

- - -The Challenge- - -

Using any VTOL (design your own or use the one I've included below), take off vertically from the starting point on the runway, pick up an item at the VAB launcher (using docking ports OR the KAS magnet (recommended)), place it at the opposite end of the runway, then land back where you started. For "the item," an Mk1-2 command pod is strongly suggested, but not required (it's a fair weight, robust, nothing to break).

Extra points are given for those who only touch the ground twice -- once at takeoff and once at landing. However, this is not required. You are certainly allowed to, say, take off, land, wheel over to the object, pick it up, wheel over to the runway, drop it off, wheel down the runway, then take off and land again. Heck, you can build a car that uses separatrons to get off the ground for a second or two. You won't get many points, but it's a good place to start.

Share your failures! I don't expect anybody to get this on the first try -- it's mostly intended so we can all learn more about VTOLs. If you notice anything that doesn't work, let us know so we don't try it either!

With permission of the owners, I'd also like to post links to the successful designs. Mine is currently included, but it's probably not the best one out there.

- - -Rules- - -

I want to make this as accessible a challenge as possible, so you are encouraged to use your own craft.

No mods are required, but KAS is recommended. If you use a magnet, don't forget it requires electric charge to operate.

Using the Airships mod to build "just" a balloon would not be in the spirit of things, but the mod itself isn't discouraged.

Since not everyone has fraps, but everybody has a "print screen" key, submissions only require three screenshots:

(1) A shot immediately after takeoff to prove you took off vertically.

(2) A shot with the object attached to your vehicle at the VAB launcher.

(3) A shot immediately before landing with a view down the runway, so we can see you landed vertically and the object was left at the end of the runway (the object itself will likely not be visible, but the HUD icon will be).

You can take screenshots using the "F1" key and they will be saved in your folder KSP_Win/Screenshots (thanks, the_BT). If you're old-fashioned like me (or your computer forces a combination with the "Function" key) the Print Screen key will do the trick as well, but since it only stores one at a time, you'll have to pause, tab out ("Alt"+"Tab"), and save in an image editor before your next one.

Videos are encouraged, but not required.

- - -

- - -Points- - -

Forgive me, for in trying to give points for not-quite-failures, I really broke things down.

Since videos are not required, it is expected that players will accurately and honestly describe their accomplishments.

- 4 points for taking off vertically.

- 5 points for making it to the VAB launcher without touching the ground, but you may land at the launcher to pick up the item.

- 4 points for picking up the item.

- An additional 7 points for picking up the item without touching the ground.

- 5 points for making it to the end of the runway without touching the ground, but you may land at the runway to drop off the item.

- 4 points for dropping off the item at the end of the runway (it may tip over or explode)

- An additional 7 points for dropping the item without touching the ground AND without it tipping over, breaking, or exploding.

- 4 points for landing vertically at the start of the runway.

- An additional 10 points for only having touched the ground twice, once before takeoff and once at landing.

= 50 points possible.

- - -Suggestions- - -

- This is definitely possible with stock parts, but the KAS magnet is recommended. That way you can worry more about a stable VTOL and less about the height of your docking ports and hovering for ten minutes while they decide to mate with each other.

- If you use the KAS magnet, don't forget that it requires electricity, and lots of it. Your engines may not replenish it fast enough, so make sure you have enough batteries to make it over to the runway without dropping your item.

- Suggest building a good plane by itself, then adding vertical engines around the center of mass.

- Suggest having your docking port/KAS at your center of mass so it doesn't change when you pick up the item:

skycranecom.jpg

- - -

- - -Questions for the Experts- - -

As this is intended to help everyone explore the world of VTOLs, I intend to post common questions here and, if answered, those answers as well.

(1) I have only one question myself, and that is: I find it incredibly difficult, once I've gotten moving, to go back to a hover. An otherwise stable VTOL just wants to tip all over the place as soon as I get below 5 m/s horizontal velocity. Any advice?

- - -Leaderboard- - -

- 39/50: Me with VTOL Mk IV

- 33/50: Nao

- - -Craft- - -

- Skycrane MkVI - http://www.filedropper.com/skycranemkvi (spaceport won't upload for some reason -- will try again shortly). Requires KAS and Aviation lights. 1 to toggle horizontal engines, 2 to toggle vertical engines and cargo lights, 0 for nav lights. Slow takeoff at about 45% throttle.

- VTOL Mk IV (since renamed to "Hammerhead MkVI") - http://www.filedropper.com/hammerheadmkvi. KAS only. 1 to toggle jets, 2 to toggle rocket assist, 7 to toggle magnet. Remote control unit on top if you prefer a forward facing nav ball (--> "Control from here").

Let's see 'em.

Edited by codepants
(1) Added note about screenshots (2) Added new craft and updated leaderboard
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Cupcake...

Cupcake...

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Nice, I'll give this challenge a go on the weekend. :) In answer to your question the problem might be caused by the fact that you've used wings and other flight control surfaces. If you're making a pure VTOL you'd be better off ditching them, as in my experience they completely mess up the handling and stability of a ship. I'm also a bit confused by your engine layout, why are the rear engines mounted at 45*?

Cupcake..

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the_bT

the_bT

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[...]

If you aren't sure about the whole "screenshot" thing, remember that you can pause KSP at any time, tab out (alt+tab), paste into Microsoft Paint, save, then return to KSP and continue. Just don't hit action group 1 instead of the Escape key. Ouch.

[...]

In KSP you can press F1 to make a screenshot. They are saved under KSP_Win\Screenshots as .png

I think I'm going to try this now...

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codepants

codepants

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Cupcake: Was hoping you'd join in. ;o) I think you'll manage to pull this one off with your mod (which looks like a great mod, by the way). It would be great to see that video, but I'll also gently suggest you try it stock, as well -- just to level the playing field. :oP

Correct me if I'm wrong, but at 0 horizontal and vertical speed, shouldn't flight surfaces have no effect? I know KSP physics aren't perfect, but even so, the number 0 generally helps things along. I would understand that, if falling, more drag in front would cause the tail to fall faster (though interestingly, the SkyCrane has wings in front and falls towards the front during a hover). I think I'll try a "pure" VTOL to see what happens, but my idea behind most of them is that they'd have to travel some distance, pick something up (say, a capsule floating in the sea), then fly back.

With the few VTOLs I've built I found angling the engines away from the center of mass (along with placing them far away from it) makes them more stable. I do have a rather small sample size, however, so if you can correct me on this, I'd be much obliged. The front engines are also at a 30* angle or so, though difficult to tell from the photo.

the_BT: Thanks! I'll add that in in a bit here. Many games have different shortcuts for this, so I usually go with ol' reliable. On my laptop you have to hold the "function" key to use any F-commands, often making it unwieldy while controlling sensitive vessels (especially if you have a time-sensitive shot). All the same, good to know. :o)

*goes to design another VTOL from scratch*

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Cupcake...

Cupcake...

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You'll have to excuse my slowness but which mod were you referring too? My designs are all pure stock, always have been. :) Anyway, in theory you're right at 0 m/s the flight surfaces shouldn't make a blind bit of difference but saying that I have noticed KSPs flight model do all sorts of weird and wonderful things that often don't make a great deal of sense. I'm just speculating here as it's not an issue I've come across with my drop ships, the majority of which I can land/hover at a speed of 0.5m/s or less, the only one that handles like a drunken pig in the atmosphere is the Cavalier and that's my only design that features wings, coincidence? Who knows. Cockpit placement can also affect the aerodynamics, but again this isn't an issue at low speeds. Hmmm, I'll be interested to know how you get on with your pure VTOL, let me know if it's still happening.

Cupcake...

Cupcake: Was hoping you'd join in. ;o) I think you'll manage to pull this one off with your mod (which looks like a great mod, by the way). It would be great to see that video, but I'll also gently suggest you try it stock, as well -- just to level the playing field. :oP

Correct me if I'm wrong, but at 0 horizontal and vertical speed, shouldn't flight surfaces have no effect? I know KSP physics aren't perfect, but even so, the number 0 generally helps things along. I would understand that, if falling, more drag in front would cause the tail to fall faster (though interestingly, the SkyCrane has wings in front and falls towards the front during a hover). I think I'll try a "pure" VTOL to see what happens, but my idea behind most of them is that they'd have to travel some distance, pick something up (say, a capsule floating in the sea), then fly back.

With the few VTOLs I've built I found angling the engines away from the center of mass (along with placing them far away from it) makes them more stable. I do have a rather small sample size, however, so if you can correct me on this, I'd be much obliged. The front engines are also at a 30* angle or so, though difficult to tell from the photo.

the_BT: Thanks! I'll add that in in a bit here. Many games have different shortcuts for this, so I usually go with ol' reliable. On my laptop you have to hold the "function" key to use any F-commands, often making it unwieldy while controlling sensitive vessels (especially if you have a time-sensitive shot). All the same, good to know. :o)

*goes to design another VTOL from scratch*

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codepants

codepants

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Ahah! Forgive me, I did not recognize some of the parts in the design for your Sherpa, but taking a closer look now, I think I can pick them all out. I think I had read your challenge just after reading one that "showcased a mod," so apparently I got the two confused. My apologies. I think the rocket assist also confused me -- actually, I'm still not sure how you do it the way you do. The exahust makes it look like the rocket is inside the jet -- ???

I can, obviously, attach rockets to the side of my jets (and have been doing that -- it's great!) but haven't been able to get it quite as smooth as it comes through in your videos. Would you mind posting a SS of how exactly the rockets are set up?

And yea, I'm a math major/physics minor so always cautious about the words "in theory," because we both know that theories only go so far. :o)

Hm, I had worked out cockpit placement affecting center of mass, but not aerodynamics. Thanks for mentioning that.

You'll have to excuse my slowness but which mod were you referring too? My designs are all pure stock, always have been. :) Anyway, in theory you're right at 0 m/s the flight surfaces shouldn't make a blind bit of difference but saying that I have noticed KSPs flight model do all sorts of weird and wonderful things that often don't make a great deal of sense. I'm just speculating here as it's not an issue I've come across with my drop ships, the majority of which I can land/hover at a speed of 0.5m/s or less, the only one that handles like a drunken pig in the atmosphere is the Cavalier and that's my only design that features wings, coincidence? Who knows. Cockpit placement can also affect the aerodynamics, but again this isn't an issue at low speeds. Hmmm, I'll be interested to know how you get on with your pure VTOL, let me know if it's still happening.

Cupcake...

Here are my efforts so far:

- I can do the takeoff/land/wheel over approach with the SkyCrane, but want to try a more airborne approach before I succuumb to easy points.

- Skycrane approach. With no rocket assist I have trouble with altitude control... need to work that in:

screenshot1.png

- Here's another asymmetric design I tried, based around giving Jebediah complete visibility of what's going on... alas, at slow speeds the mass doesn't quite balance out (it's close!) and have killed many of Jeb's relatives in testing:

screenshot2.png

- Wanted to try as simple as possible while keeping thrusting points some distance away from the center of mass. This is the closest I've gotten (!!!), but when I got close to the runway hit "toggle magnet" instead of "rocket assist" and dropped the pod to its death:

screenshot6.png

- 4 points for taking off vertically.

- 5 points for making it to the VAB launcher without touching the ground, but you may land at the launcher to pick up the item.

- 4 points for picking up the item.

- An additional 7 points for picking up the item without touching the ground.

- 5 points for making it to the end of the runway without touching the ground, but you may land at the runway to drop off the item.

- 0 points for dropping off the item at the end of the runway (it may tip over or explode)

- An additional 0 points for dropping the item without touching the ground AND without it tipping over, breaking, or exploding.

- 4 points for landing vertically at the start of the runway.

- An additional 10 points for only having touched the ground twice, once before takeoff and once at landing.

= 39 points/50 points possible.

Edited by codepants
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Nao

Nao

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I went with a conservative fool proof design Jet engines+ASAS and RCS for fine control.

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Unfortunately due to a bug i had to land (and go to Space Center) after both picking up and dropping the cargo as the ship(s) had their attitude frozen.

With ASAS+RCS the docking part was so easy i had one hand on F1 button and second on IKJLHN and did it from cockpit.

Since i didn't take takeoff screenshot the first time, i went and launched it again, and started messing around (some shots of landing on buildings included).

Counting it up: - 4 points for taking off vertically, - 5 points for making it to the VAB launcher without touching the ground, - 4 points for picking up the item, - 5 points for making it to the end of the runway without touching the ground, - 4 points for dropping off the item at the end of the runway, - An additional 7 points for dropping the item without touching the ground AND without it tipping over, breaking, or exploding, - 4 points for landing vertically at the start of the runway. = 33 points :P

I maybe record a video of another run for 50points if I figure out how to prevent the rotation freeze bug.

Cheers!

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Cupcake...

Cupcake...

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actually, I'm still not sure how you do it the way you do. The exahust makes it look like the rocket is inside the jet -- ???


:) You got it in one! It's a bit naughty of me but I've been using small cubic struts to attach two engines to the same mounting, it's something I first did with the Orca which shares the same power-plant as the Sherpa. The main advantage of it is that it helps get rid of the throttle lag from the jets. It's a bit hard to explain exactly how it's done but you can download one of my ships from the Bazaar and do an autopsy. I've called it rocket assist as the rockets don't put out enough power on thier own to lift the craft, they're purely they're to work in conjunction with the jets.



I can do you tutorial if you like but it'll have to wait a week or so I'm afraid. Also considering the challenge takes place in a small area you could get away with ditching the jets altogether and just using rockets. A VTOL with a T/W of 1 using a aerospike engine will give you around 5 mins burn time at full throttle, more then enough for the challenge. As far as the smooth control goes I think a lot of it comes down to the fact that I'm using a joystick and analogue throttle (Nao managed to complete my challenge using a keyboard, but I suspect he's a masochist). :wink:

Cupcake...
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