CLOSED -- Flying Duna AGAIN (Thanks for Participating)

[Geschosskopf]

Back in August I posted this challenge and nobody said anything in the thread except me and Bothersome despite it getting over 1000 views. At that time, I spoke a bit prematurely but I have now accomplished the feat, so I'm seeing who out there wants to top me. I've also revised the rules a bit. Here we go:

CHALLENGE:

Build a ship that can fly on Duna and meet the following design specs:

1. The ship must be flown carrying a minimum of 2 Kerbals.
   
2. The only source of lift must be the result of aerodynamic forces acting on wings/rotors, so airplanes and helicopters are OK but anything held up by rockets, RCS, balloons, etc., is not.
   
3. The ship must derive its forward motion from an actual engine/motor of some sort. IOW, no infinigliders (sorry, Bothersome).
   
4. The ship itself must be delivered from the ground on Kerbin to the ground on Duna as a complete item. Once it leaves the VAB/SPH, no adding to or subtracting from what will actually fly around on Duna once it gets there, other than resource and crew transfers.
   
5. What moves the ship from Kerbin to Duna can change. Drop boosters on launch, add a transfer stage in orbit, detach de-orbit and skycrane things during landing, etc., all OK. But the ship actually has to be flown from the ground on Kerbin, so no Orbital Construction, no Extraplanetary Launchpads, no HyperEdit, etc.
   
6. Of course, no infinite fuel or any other things from the cheat/debug menu.
   
7. Once at Duna, the ship must enter the atmosphere and make a safe landing at a minimum altitude of 2500m.
   
8. After the initial landing, the ship must be able to take off again from a 2500m altitude and, carrying at least 2 Kerbals, be able to maintain an altitude of at least 5000m in level flight, then land safely again.
   
9. The ship must have a FLYING range that allows it to fly at least 1/2 way around Duna without refueling. FLYING range means that it never goes on an orbital or suborbital trajectory but flies through the air the whole way like an airplane or helicopter.
   
10. The ship must be capable of long-term use on Duna. If the ship uses consumable resources, there must be a way to replenish them. If it has parachutes, there must be access for Kerbals to repack them.
    
11. There is no requirement that the ship ever leave Duna. The idea is, this is to support several permanent facilities on Duna.
    
12. All mods, except those that circumvent the above rules, are OK, but don't tweak their config files so everybody's got the same parts to work with. However, welding parts together simply to reduce part count, without conferring any other benefit, is OK, too.
    

WINNING

To be considered eligible, the ship must satisfy all the above requirements. Ranking is determined by "extra credit" bonus points, as follows:

• +1 for each Kerbal carried above the minimum of 2.
  
• +1 for all Kerbals being inside instead of outside in lawn chairs.
  
• +1 for each ton of non-Kerbal cargo the ship can carry while meeting all other requirements.
  
• +1 for every 1000m above 5000m the ship can maintain altitude.
  
• +1 for being able to circumnavigate Duna without refueling and without going on a ballistic trajectory.
  
• +1 for using FAR (EDIT correction)
  
• +2 for doing this with an SSTDABTK (single stage to Duna and back to Kerbin).
  
• EDIT: Due to the IMHO overpowered nature of the Interstellar mod, ships using it are in a league of their own, so there is now a separate leaderboard for them.
  

Ties will be broken by a more detailed examination of what went into the above bonus points. For example, the highest flying altitude obtained, 1/2 a ton more cargo, etc.

Non-Interstellar Leaders:

1. Sensi: 20 bonus points (17 total Kerbals, 7000m altitude, 2(.8) tons of cargo, circumnavigation)

2. ID-1()T's VTOL: 15 points (13 Kerbals, 7200m, circumnavigation, FAR)

3. sdj64's ALL STOCK Ion Plane: 14 points (6 Kerbals, 14000m, circumnavigation, and 1/2 ton of cargo as a tie-breaker)

4. StevenRS11: 13 bonus points (circumnavigation, FAR, 7000m, 11 Kerbals total) Only works in 0.22

5. Kaa253: 11 bonus points (5 Kerbals all inside, 4.2 tons cargo, 6750m altitude, circumnavigations, FAR)

6. Fengist: 10 bonus points (5 extra Kerbalsl inside, 2 tons of cargo, 6000m altitude, circumnavigation)

7. DaMichel: 5 bonus points (Kerbals all inside, 7000m cruising altitude, circumnavigation, and FAR)

8. Sirine: 3 bonus points (circumnavigation, 2 Kerbals both inside, 6000m cruising (6701 highest attained), very cool concept, ALL STOCK

9. 1D-1()T: 2 bonus points (circumnavigation, 3 Kerbals, looks better than mine)

10. Geschosskopf: 2 bonus points (circumnavigation and 6000m cruising altitude) -- See below.

11.

12.

Insterstellar Leaders:

1. StevenRS11: 89 bonus points (circumnavigation, 18Km altitude, 73 total Kerbals all inside, FAR, SSTDABTK) only works in 0.22

2.

3.

4.

5.

EDIT:

HONORABLE MENTION:

1. Brotoro for his circumnavigation in 0.90 with a combination of ions and rockets with refueling along the way. In all respects other than carrying 2 Kerbals, he completed this challenge.

EDIT:

THE PRIZE:

All who make a ship meeting the general requirements, whether they win or not, get to sew this patch on their flight jackets. Hey, I'm no artist but this is a lot of work and you all should have something to show for it.

Here's Mine

I made a large biplane called the D'OH (Duna Overflight Hybrid) powered by Firespitter electric props using a hybrid solar-electric/Kethane-electric power plant. It carries 2 Kerbals in lawn chairs, enters the atmosphere, can take off again from 2500m, can cruise at 6200m, can land safely, and can do this indefinitely. Due to sunshine being brighter on Duna, the Kethane generator hasn't yet been needed there so it's all solar with infinite range (during daylight).

After must frustration, I managed to get it into orbit as an SSTO spaceplane:

Then I docked it to a transfer stage and flew it to Duna.

At Duna, after using the big rear wings on the ascent stage for aerobraking, it ditched them and then the rest of the SSTO assent stage after the de-orbit burn.

Then it landed under probe control at a Kethane station I'd already established. This airbase has Kethane drills, refintery, power to run them, and a fuel bowser rover with KAS to go refuel the D'OH.

The crew of 2 Kerbals then landed, boarded the D'OH, and off they went. In the MapSat view, the starting point is the left end of the horizontal purple line near the left center of the pic. I flew it to The Face by a route about 360km long all on solar power, not burning a drop of Kethane.

Highest altitude obtained was 6290m but it couldn't hold this. It could, however, hold 6200m.

Then it landed safely at The Face.

Tomorrow (on Duna), it will go looking for the buried rover. More details can be found starting at this post:

http://forum.kerbalspaceprogram.com/threads/43871-The-Kethane-Travelling-Circus-EPISODE-14-The-Flight-of-the-D-OH!?p=653139&viewfull=1#post653139

Edited May 24, 2015 by Geschosskopf
giving sdj64 the notice he deserves for doing this stock. My bad for not mentioning this before.

[Hakari]

While that's not a bad challenge, but whenever you point your craft above the horizon you are using part of your propulsion as upward lift. And if you never do that you would never get into orbit.

[Fengist]

There's probably a very good reason why you didn't and won't get many to do this.

The only engines you'll get to work on Duna are Kethane and the electrics you use. Kethane engines on Duna are practically useless.

1. Kethane engines on Duna flame out at around 5 km.

2. Half of Duna's terrain is 4 km+

3. With Kethane engines you end up having to run full throttle in order to keep the air intakes going.

4. You have to fly full throttle on Duna to get to 4+km altitudes.

5. The the faster and higher you fly, the less air the intakes get.

6. The less distance between your plane and the ground, the less horizon you're able to see and thus prepare for.

On Duna, you flame out at 400+m/s and you're less than 1km above the surface. There's not nearly enough air to slow you down. At 4km+ the control surfaces are practically useless so trying to glide is futile. And parachutes for landing are just as deadly as landing without them. Duna is FAR from flat. Net result, you end up plowing into the side of a sand dune at 300+/ms because you couldn't glide or turn to avoid it.

The ONLY place where Kethane engines on Duna are reliable are in the huge depression that's at 2,500m and it certainly doesn't go half way around the planet.

How do I know this. I've been testing it for a circumnavigation challenge that I've pretty much deemed too difficult (for stock + kethane anyway)

[Geschosskopf]

There's probably a very good reason why you didn't and won't get many to do this.

The only engines you'll get to work on Duna are Kethane and the electrics you use. Kethane engines on Duna are practically useless.

Actually, there are quite a few folks who've successfully flown Kethane jets on Duna. You just have to understand how the engine works. It's not at all like a regular jet engine where the IntakeAir goes away with altitude. Instead, the availability of KintakeAir is almost entire a function of speed vs. throttle setting. While there does have to be some minimal atmospheric pressure to have KintakeAir at all, what actually controls the supply is a combination of the current speed compared to the current throttle setting. The Kethane jet is designed to work at high throttle and low speed (like on Eve with all its drag). If you ever get too fast for the current throttle setting, the KintakeAir goes away all at once. There is no gradual tapering off with increased altitude. So, the trick is to figure out a way to fly within this engine's unique parameters.

Anyway, flying on Duna is difficult no matter what propulsion system you use. That's why this is a challenge. And flying on Duna is only 1/2 the problem. Getting a Duna plane off Kerbin can be just as difficult.

So, if you don't want to play, don't. But don't say something can't be done when it very surely has been.

[Geschosskopf]

While that's not a bad challenge, but whenever you point your craft above the horizon you are using part of your propulsion as upward lift. And if you never do that you would never get into orbit.

Well, lift comes from forward speed so technically the engines are always making lift no matter which way the nose is pointed. But you know that's not what I mean. Besides, lift is a function of angle of attack, so in most cases (especially on Duna), the nose is always above the prograde vector (and well above the horizon) in level flight.

There is no requirement to get the ship off Duna, just Kerbin. You're free to assume the ship will be there permanently shuttling stuff between a couple of permanent colonies. But you can get extra points if it can indeed get home. The only thing is, while on Duna, you can't fly it like a suborbital rocket.

[ultra86]

I almost completed this challenge using one of my own designs last week. I don't think I would have met the travel 1/2 way around Duna portion of the challenge, but otherwise my space plane took off from Kerbin, made it to Duna, and after about 12 attempts I finally landed it in one piece. I was using 4 mini nuclear rocket engines from the Kerbal smaller stock pack (or whatever it's called) when flying around Duna, they provided plenty of thrust to fly. I was carrying a considerable amount of fuel so I was able to cruise around for a while (though getting to where I wanted to go was a challenge). The low gravity makes it extremely difficult to land, and the thin air makes it extremely difficult to maneuver (at least my design). The lack of flat landing space is also a challenge (perhaps I haven't explored Duna enough yet).

[Geschosskopf]

I almost completed this challenge using one of my own designs last week.

Keep at it and I'm sure you'll succeed .

The lack of flat landing space is also a challenge (perhaps I haven't explored Duna enough yet).

Yeah, I found this one of the harder aspects of the problem myself. I found that landing any faster than about 50m/s was pretty much a guarantee of an eventual somersault or even a face-plant into the side of the next dune. And I never could figure out a way to use parachutes effectively. I just wanted to drag one behind to slow me down but it always made me lawn-dart. So, as you see, what I ended up with was a biplane with a huge wing, which even at 2500m can float along at about 35m/s. But even with all 16 airbrakes deployed and landing with the wheel brakes locked, the thing will still bounce several hundred meters after touching down. So I had to build it tough to take rough landings and make it very hard to nose over. It's been working so far.

I also hear you on the difficulty of maneuvering. The D'OH bleeds altitude when turning. On my trip to The Face, I lost about 800m just making a 45^ turn. Thus, setting up for a landing approach usually requires setting up the approach from about 20km away after making a very gradual turn about 10km in diameter.

But that's why flying on Duna is a worthy challenge. If you can fly on Duna, you can fly anywhere .

[1D-1()T]

I'm working on this at the moment, mostly for an excuse to use the Kethane powered jet. If I get anywhere I'll post it.

[ultra86]

Yeah, I found this one of the harder aspects of the problem myself. I found that landing any faster than about 50m/s was pretty much a guarantee of an eventual somersault or even a face-plant into the side of the next dune. And I never could figure out a way to use parachutes effectively. I just wanted to drag one behind to slow me down but it always made me lawn-dart. So, as you see, what I ended up with was a biplane with a huge wing, which even at 2500m can float along at about 35m/s. But even with all 16 airbrakes deployed and landing with the wheel brakes locked, the thing will still bounce several hundred meters after touching down. So I had to build it tough to take rough landings and make it very hard to nose over. It's been working so far.

I know rockets aren't allowed for lift, but one idea would be to mount a series of upward facing Rockomax 24-77's and enough rocket fuel to fire them for a few seconds during several landings. Should stick you to the ground pretty well and allow the brakes to kick in to slow you down before the wobbling/tumbling starts.

This is def a worthy challenge.

[Fengist]

Actually, there are quite a few folks who've successfully flown Kethane jets on Duna. You just have to understand how the engine works. It's not at all like a regular jet engine where the IntakeAir goes away with altitude. Instead, the availability of KintakeAir is almost entire a function of speed vs. throttle setting. While there does have to be some minimal atmospheric pressure to have KintakeAir at all, what actually controls the supply is a combination of the current speed compared to the current throttle setting. The Kethane jet is designed to work at high throttle and low speed (like on Eve with all its drag). If you ever get too fast for the current throttle setting, the KintakeAir goes away all at once. There is no gradual tapering off with increased altitude. So, the trick is to figure out a way to fly within this engine's unique parameters.

Anyway, flying on Duna is difficult no matter what propulsion system you use. That's why this is a challenge. And flying on Duna is only 1/2 the problem. Getting a Duna plane off Kerbin can be just as difficult.

So, if you don't want to play, don't. But don't say something can't be done when it very surely has been.

Did you read what I said? Stock + Kethane. And I didn't say flying one was impossible, I have one on Duna. Read. I said circumnavigating stock+kethane would be too difficult for a challenge.

[Geschosskopf]

Did you read what I said? Stock + Kethane. And I didn't say flying one was impossible, I have one on Duna. Read. I said circumnavigating stock+kethane would be too difficult for a challenge.

I read your post. You falsely stated that Kethane and electricity are the only ways of flying Duna. You didn't understand how the Kethane engine works, which led you to the incorrect conclusion that flying Duna with stock+Kethane is impossible. I tried to tell you how the Kethane engine really works so you'd be able to participate even with your self-imposed restrictions on mods.

So, there we are. If you feel up to the challenge, get cracking. If you're not going to participate, then stop trolling and go away.

[Fengist]

I read your post. You falsely stated that Kethane and electricity are the only ways of flying Duna. You didn't understand how the Kethane engine works, which led you to the incorrect conclusion that flying Duna with stock+Kethane is impossible. I tried to tell you how the Kethane engine really works so you'd be able to participate even with your self-imposed restrictions on mods.

So, there we are. If you feel up to the challenge, get cracking. If you're not going to participate, then stop trolling and go away.

Please click the link in my signature and tell me again I don't know how Kethane engines work. And again, I never used the word impossible. I suggest that if you wish me to quit responding then you need to quit putting words in my mouth.

[Geschosskopf]

I'm no artist but I made a little graphic you can add to your sig if you can do this challenge. It's now included in the 1st post.

[Northstar1989]

Difficult challenge Geschosskopf- but the hardest part is getting the thing to orbit from Kerbin!

Inspired in part by your Kethane Traveling Circus episodes, I already built an all-electric plane that's almost up to the challenge- it can cruise at 16000 meters on Kerbin (that's the same pressure as 4770 meters on Duna) and is plenty maneuverable and powerful for the job. The first problem is, after about 16000 meters, the Firespitter electric propellers I used (and you used in the D'OH) start to leak coolant (FSCoolant)- and stop working soon after that when they run out! How did you get your plane to over 6000 meters on Duna? The propellers should have lost all their coolant long before then...

The second problem I face, is, as I said, getting the darn thing to orbit. You see, I built the thing in Career mode (bonus points for doing it in Career mode before discovering all the nodes, anyone?) and I haven't even discovered Ramjet engines yet, nonetheless SABRE ones (I'm running B9 Aerospace, KAS, Firespitter Mod, NovaPunch2, Near-Future mod- which is balanced and realistic advanced ion engines and nuclear power, and Multipanels 1.0- which basically is just a static panel weld mod)- either of which would be required to get the thing high enough to orbit it like a spaceplane. So it's going to be a real hassle getting the thing into orbit- I'm pretty sure the lift of the thing would tip any rocket over I sat it on top of or on the side of... My only option (before discovering more tech nodes) seems to be sending TWO copies of the plane to Duna, on each side of a huge rocket- but the part count for that on the Launchpad would kill my weak/slow computer (or invite the Kraken over for dinner)...

Let me know if you have any ideas- otherwise, it's waiting until I get better propulsion methods (SABRE, or at least Ramjet engines) so I can send the thing to orbit via spaceplane, like you did in the KTC... That is, if I don't lose interest in the challenge before I get to the node...

As a side-note, I've recently been experimenting with using Turbojet engines alone to get to orbit (they pop up on the tech tree intermediate between basic jet engines and ramjet engines when you have B9 Aerospace installed). They make it to a vaguely suborbital trajectory (63,350 meter apoapsis), but I haven't quite been able to get up to 80,000 meters or so with them yet (where I'd have enough head-room for an orbital burn)

[Northstar1989]

Yeah, I found this one of the harder aspects of the problem myself. I found that landing any faster than about 50m/s was pretty much a guarantee of an eventual somersault or even a face-plant into the side of the next dune. And I never could figure out a way to use parachutes effectively. I just wanted to drag one behind to slow me down but it always made me lawn-dart.

By the way, did you try placing the parachutes right on the center of mass of the plane? In my medium-altitude electric plane design (the one I just posted about) I was having the same problem, until I moved the parachutes to directly on top of the center of mass.

Basically, parachutes tend to exert torque on your craft if they're placed off-COM, which is what makes your plane lawn-dart. So, you're left with two options- try and balance the torque with parachutes on both ends- which is tricky to get right at best unless your craft is front-to-back symmetrical as well- or place the parachutes right on the COM.

The plane will still tend to tip some- you'll never get the 'chutes exactly on the COM- but if you're close enough you can stop the thing from tipping tail or nose-up (depending on which end the parachutes are on) with control surfaces alone.

[Geschosskopf]

Inspired in part by your Kethane Traveling Circus episodes, I already built an all-electric plane that's almost up to the challenge- it can cruise at 16000 meters on Kerbin (that's the same pressure as 4770 meters on Duna) and is plenty maneuverable and powerful for the job. The first problem is, after about 16000 meters, the Firespitter electric propellers I used (and you used in the D'OH) start to leak coolant (FSCoolant)- and stop working soon after that when they run out! How did you get your plane to over 6000 meters on Duna? The propellers should have lost all their coolant long before then...

I honestly don't know. But as you can see from the screenshots in the KTC thread where the resource tab is open, even above 6km on Duna I still have about 1/2 the FScoolant. Perhaps it has something to do with Duna's lower gravity? Or that Duna's atmosphere isn't oxygen? Or that Duna's colder than Kerbin so there's less need of coolant? Or maybe the mod's code works on ASL and not pressure altitude so the engines think they're in thicker air than they really are. I have no idea. Also, solar panels work better on Duna than they do on Kerbin, I'm guessing because the atmosphere's thinner even though Kerbol is further away.

In any case, during the course of building the D'OH, I discovered that high altitude on Kerbin isn't a good approximation of Duna for whatever reason. Plus, there's no ground that high to practice landing and taking off on. So, there was nothing for it but to "build a Duna simulator". Meaning, in a separate save file from the KTC, I used HyperEdit to put the various prototypes into Duna orbit with a small deorbit stage slapped on. That way, I could test the whole thing from initial atmospheric entry to landing, taking off again, and flying around. Once I had something that could fly on Duna, I copied it over to the KTC file and set about working on getting off the ground on Kerbin.

The second problem I face, is, as I said, getting the darn thing to orbit. ... My only option (before discovering more tech nodes) seems to be sending TWO copies of the plane to Duna, on each side of a huge rocket- but the part count for that on the Launchpad would kill my weak/slow computer (or invite the Kraken over for dinner)...

Let me know if you have any ideas- otherwise, it's waiting until I get better propulsion methods (SABRE, or at least Ramjet engines) so I can send the thing to orbit via spaceplane, like you did in the KTC... That is, if I don't lose interest in the challenge before I get to the node...

Yes, a plane with enough wing to fly on Duna won't ride up vertically on top of a rocket--ask me how I know . I know of 3 alternative methods. One you've already thought of, 2 copies of the plane. Part count killed me on this, too. The second I call the "Bothersome Method" after the guy who explained it to me. In this one, you use the airplane's wings as the tailfins of the rocket and build several boosters on outriggers surrounding, with more on the top side so the asymmetrical thrust balances the asymmetrical lift and the CoM is above the CoL as it should be. Never could get that to work. The 3rd method is to turn it into a horizontal take-off spaceplane, which is how I eventually got the D'OH into orbit. You can see pics of this monstrosity in the KTC thread. What I did was put some fuel and SABREs behind the D'OH with some of the B9 Heavy Wings and fiddled with their positions to get the CoM and CoL lined up correctly, taking the D'OH's wings into account. After much work tuning the fuel ratios, I finally got this to work. And when I did, it was the sweetest-flying spaceplane I've ever made. It just walked on up there without any of the typical control difficulty. It had so much wing it never had much angle of attack so leveling off for speed at 20km was no problem--it practically did it by itself. Once in orbit, I docked on a transfer tug and off to Duna.

Aerocapture at Duna was a bit tricky. First, I got a REALLY bad encounter due to a glitch with the patched conics. Then, having the heavy transfer tug on the back end, which I had to keep to fill up the D'OH with Kethane before landing, screwed the CoM. Thus, I couldn't go very deep without getting dangerously unstable, which meant I had to make a significant burn. Good thing I brought enough fuel for that .

I never put chutes on the D'OH, just earlier prototypes. I agree, CoM placement is the only way to prevent lawndarting, but it raises other problems. First off, CoM chutes have to be your sole means of descent because you can't keep going forward, so you need enough of them to get your vertical speed down into the safe range. Which on Duna, especially with the challenge requirement of landing and taking off at a minimum of 2500m ground level, means a LOT of chutes, at least with something as big as the D'OH. I did check the parachute calculator while building the D'OH and found I needed like 6 or 8 TONS of chutes. Given that I'd had to pare weight to the bone just to get the D'OH to fly at all, I could tell that wasn't going to work, so instead focused on making the D'OH able to fly slow, tough enough to bounce, and very unlikely to flip over.

Edited October 31, 2013 by Geschosskopf

[1D-1()T]

http://imgur.com/a/hK1Mz#0

That is an album of my plane. Like yours Geschosskopf, it is a hybrid, and uses the firespitter electric props. It is capable of infinite flight in daylight.

The tally

+1 - Can carry 3 Kerbals

+1 - One of them is inside

+1 - Circumnavigation

That comes to three points, I believe. It can make over 6000, but only for a few minutes.

By the way, there is another way to get them off Kerbin, launch them backwards

Thanks for a great challenge

[Geschosskopf]

http://imgur.com/a/hK1Mz#0

That is an album of my plane. Like yours Geschosskopf, it is a hybrid, and uses the firespitter electric props. It is capable of infinite flight in daylight.

The tally

+1 - Can carry 3 Kerbals

+1 - One of them is inside

+1 - Circumnavigation

That comes to three points, I believe. It can make over 6000, but only for a few minutes.

By the way, there is another way to get them off Kerbin, launch them backwards

Thanks for a great challenge

Well done! Bravo! Kudos! Be sure to snag the Flying Duna Challenge patch off the 1st post and slap it in your sig. I'll be updating the standings with you in 1st place as soon as I finish this post. But I think you only got 2 bonus points because not all the Kerbals are inside, which is what I meant. Still I think yours is better than mine from an engineering POV.

Your plane looks much more elegant than mine. I knew somebody would find a more aesthetic way of doing this . I might have to steal some of your ideas so please elaborate on its features and flying characteristics. I take it from the landing gear that it lands like an albatross

And great idea about launching it backwards.

Edited November 1, 2013 by Geschosskopf

[1D-1()T]

Oh, whoops, didn't notice that ALL the kerbals needed to be inside for the extra point. Sorry.

Not sure quite what you mean by 'lands like an albatross', but if you apply the brakes to heavily it is prone to either going onto the front wheel or flipping.

One feature that I really like is I set up an action group to put the motors in reverse, so I can land in a much shorter distance. I also use it to slow to a stop once I have landed.

Also, how to I put the patch in my sig?

Edit: Just looked up how an albatross lands, and yes, I kill most of my speed a meter or so up, and just pancake land, hopefully without going splat.

Edited November 1, 2013 by 1D-1()T

[Geschosskopf]

One feature that I really like is I set up an action group to put the motors in reverse, so I can land in a much shorter distance. I also use it to slow to a stop once I have landed.

I didn't realize this was possible until the D'OH was already on Duna .

Also, how to I put the patch in my sig?

First, right-click on the patch and "Save Picture". That gets it on your HD. Now you have to upload it somewhere like Imgur so this forum can access it.

Then look up at the very top of the forum for the long row of links. One of them near the middle on the lower row says "Forum Actions" and has a drop-down arrow. Click that drop-down and at the bottom of the resulting list you'll see "Edit Profile". Click that. On the new page, on the left edge about halfway down is a sidebar that says "My Settings". The 1st part of this is "My Profile" and the 4th thing under that heading is "Edit Signature". Click that. This brings up what's like the Quick Reply box you type posts in, wherein you enter the signature you want using all the UBB codes. Use the [ img ] .... [ /img ] tags with the URL of the image inside to have the patch become part of your sig.

Edit: Just looked up how an albatross lands, and yes, I kill most of my speed a meter or so up, and just pancake land, hopefully without going splat.

[1D-1()T]

There is this

http://forum.kerbalspaceprogram.com/threads/24882-Actions-on-the-Fly-Edit-your-action-groups-in-flight-mode

mod that let's you edit action groups after launch.

Once again, thanks for a great challenge! +1

[Patupi]

Yeah, I use that all the time! Also, on the issue with launching a plane on a rocket... I really haven't used FAR much, but if that's installed doesn't it cancel out lift as well as drag from parts that are 'protected' by components ahead of it? IE fairings etc. Not sure whether you consider FAR adjusting aerodynamics too much to be allowed for a plane challenge anyway, but I thought I'd ask.

[Geschosskopf]

Yeah, I use that all the time! Also, on the issue with launching a plane on a rocket... I really haven't used FAR much, but if that's installed doesn't it cancel out lift as well as drag from parts that are 'protected' by components ahead of it? IE fairings etc. Not sure whether you consider FAR adjusting aerodynamics too much to be allowed for a plane challenge anyway, but I thought I'd ask.

In this challenge, all mods are fair game except those that defeat the spirit of the game. IOW, I have no problem with HyperEdit used to merely to test how your plane flies on Duna, but you still have to launch and transfer it there without it. And IIRC, you get a bonus point for making completing this challenge using FAR. If not, I'll go and add that now because that was in the original version of this challenge.

I haven't used FAR since 0.20 so I can't speak with authority on how it acts these days. However, back then, FAR really like rockets to be like arrows. That is, long and skinny with the weight at the front and tail feathers at the back. FAR also created a lot of lift off fairings. The reasons for using fairings thus were to reduce drag and to make the lift and drag of the payload symmetrical. But the more fairing you had on the top, the more tail feathers you needed on the bottom to pull the CoL down well below the CoM. I used to use stock delta wings with standard control surfaces as my tail fins instead of the usual winglets.

Anyway, a plane that can fly on Duna needs to have an extremely low wing loading (low mass, huge lift). If this is on the top of the rocket, it's exactly the opposite of what FAR liked back then and probably still likes. And the lift would be asymmetrical. I suppose that you could only cover this up with a procedural fairing, but FAR would probably still give that a huge amount of symmetrical lift. So you would probably have to build huge B9 or procedural wings on the bottom to make it launch correctly.

[Northstar1989]

http://imgur.com/a/hK1Mz#0

That is an album of my plane. Like yours Geschosskopf, it is a hybrid, and uses the firespitter electric props. It is capable of infinite flight in daylight.

The tally

+1 - Can carry 3 Kerbals

+1 - One of them is inside

+1 - Circumnavigation

That comes to three points, I believe. It can make over 6000, but only for a few minutes.

By the way, there is another way to get them off Kerbin, launch them backwards

Thanks for a great challenge

WOW, if *THAT THING* can fly on Duna, my electric planes from before certainly could have too. They have essentially the same general design- but mine was upsized and optimized a bit for higher thrust (about 1/3 greater relative to mass), higher lift (maybe 25-30% more), and about the same wing load... It probably flies that high on Duna (whereas that design wouldn't have reached even 17,200 meters cruising altitude on Kerbin) due to the lower gravity...

Actually, about the solar panels Geschosskopf- the atmosphere on Duna is going to be similar at max cruising altitude on Kerbin and Duna in terms of thickness (a bit less on Duna, as the reduced gravity means cruising is possible at lower atmospheric pressures). What I'm pretty sure the main difference is, is the scale height. Since Duna's atmosphere has a smaller scale height than Kerbin's (that is, it falls off more rapidly), you have less atmosphere above you at a give pressure level there. Which means less atmosphere to interfere with the sun's light, even though solar radiation *IS* weaker there...

Unfortunately, somehow my craft files got corrupted for the electric planes I designed for Duna (I think it might have been from some additional mods I installed- all my SPH designs but one were corrupted- they fell through the runway and crash the game when launched. On that note, I also lost some traditional jet designs,and an adaptation I made of my Duna flier for the Kerbal Airliner Challenge that never circumnavigated due to the severe lag from all the External Command Seats I strapped on for crew capacity...), and I don't have the heart to design it all over again.

However, I downloaded the KSP Interstellar mod, added it my Career save, and developed an even better design! I introduce, the Nuclear-Powered Thermal Turbojet! Here's a couple images, and I'll post a craft file just as soon as somebody can tell me how to get the darn Forum file attachment system working right now (I can't find the button to attach files?)

Note that the second image is a slightly earlier version than my current working one- I moved the parachutes a tiny bit closer to the COM and adjusted them so they weren't clipping into (read- almost completely concealed by) the front winglets, which I added into the design after the parachutes.

I've found it's an excellent design, able to reach 18,750 meters cruising altitude on Kerbin- shattering my previous record with electric propellers. Because it's a type of jet, rather than propeller, the engines still work very well at that altitude- so it could conceivably fly much higher if I could find a good way to reduce its wingload or increase its thrust further. It's still in the prototype stages- I'll send an improved version (with crew capacity for 2, instead of 1) to Duna. I've also FINALLY developed SABRE engines not long ago (the tech node is really expensive, and advanced)- so I'll be able to use that to get it off Kerbin- since I assume you won't take kindly to my using my newly-installed (but thus far largely unused- except for an orbital scrapper/recycler ship I built with it and an Extraplanetary Launchpads recycling part to clear debris from Kerbin orbit...) Orbital Construction mod to simply build a copy in-orbit...

Which brings me to another point- there are actually TWO ways to increase a plane's altitude ceiling. ONE is to increase lift relative to its mass, or decrease mass relative to lift (reducing "wingload"). The OTHER is to increase thrust relative to wingload- thus increasing max speed and making the existing wings effectively provide more lift, and reducing the effects of gravity if flying in the direction of the planet's rotation... I've taken more this approach with my Nuclear Powered Thermal Turbojet, since I find adding too many wings and winglets drastically increases my game's lag... (my electric propeller design I was going to launch to Duna, while it did carry 5 propellers- which could only be fully powered near maximum altitude where the sunlight was strongest- still mostly relied on minimizing wingload to raise its altitude ceiling- as propellers work very poorly at high altitude).

As a side-note, the high mass, high thrust approach actually works BETTER on Duna than on Kerbin- where the lower gravity means that you essentially get penalized less for the extra mass, whereas you still see the same benefits from the TWR.

Now, finally, you must be asking by now "What exactly is a Nuclear Powered Thermal Turbojet?" Well let me tell you. A turbojet, as you know, relies on pushing exhaust out the rear of the plane to achieve thrust. A traditional/conventional turbojet achieves this by combusting jet fuel. However, as we all know, jet engines don't work on Duna thanks to the lack of any substantial amount of oxygen there...

A thermal turbojet, on the other hand, works on a slightly different principle. Rather than relying on combustion to generate thrust, it relies on heat transfer to air passing through the engine- superheating it and then pushing it out the rear of the engine. "How do you heat this air if you can't combust fuel?", you might ask. Simple. You pass it over a small nuclear reactor. Now a nuclear reactor isn't exactly light- but if you can manage to lift one into the air on a plane, you have a very efficient means of propulsion- one that can last for YEARS without needing refueling (provision of fresh uranium supplies for the reactor).

The plane's reactor's uranium supply doesn't last forever, though. That's where the other components of the KSP Interstellar, and the Kerbal Attachment System (or hard-docking, if you're feeling really masochistic) mods come into play... Since KSP Interstellar mod introduces nuclear reactors that *DO* consume Uranium Hexafluoride (the "UF6" in my screenshot resources tab) at a very slow rate; it also introduces a way to replenish that nuclear fuel supply- albeit a slightly expensive/unwieldy one.

The nuclear fuel doesn't simply disappear as the reactor utilizes it. Instead, like in real life, depleted uranium rods are left over (the "DUF6" in my screenshot resources tab). The mod allows these rods to be reprocessed, re-enriching the uranium at a Science Lab with a sufficiently powerful nuclear reactor attached to it (which is used as a breeder-reactor: look it up if you're not sure what that is). So, you can recycle the uranium, prolonging the service life of your nuclear-powered craft essentially indefinitely.

I've never actually used the re-enrichment system yet, as I just installed the mod, and like in real life the nuclear fuel supply is consumed VERY slowly- with most nuclear reactors taking something on the order of years to exhaust their uranium supply. However, I know the reprocessing can be done- and since I intend to greatly reduced the uranium loading of my plane's reactor to save weight (like in the screenshot- the three reactor cores it hosts can normally hold up to 0.60 UF6- however I only have a bit less than 0.03 loaded on the plane for the test flight- thanks to TAC Fuel Balancer...), I might have to do it sooner rather than later. The UF6 isn't light, by the way- a single reactor (which is already rather heavy to begin with) holds only 0.20 UF6- but that much fuel weighs a solid 1.0 TON of weight in the game... Hence why I reduced my plane's loading for the test-flight to determine maximum cruising altitude (a bit over under 19,000 meters on Kerbin- but I rounded it down to the nearest 250-meter mark for safety).

The strategy of increasing thrust (and thus airspeed) relative to wingload in order to raise maximum altitude has another benefit, by the way. The plane moves a lot FASTER! Which means, it won't take me nearly as long to circumnavigate Duna (even with a greatly reduced nuclear fuel supply, my design should easily be able to fly for several weeks or more of continuous flight- which is more than enough time to get anywhere my Kerbals are going, and then eventually return for some freshly-enriched uranium from a Science Lab base-site on Duna. In real life, the thermal turbojet engine would probably need maintenance long before the fuel supply ran out.)

So, it's not a cheat-mod. The thrust isn't free (the necessary nuclear reactors are VERY heavy, and still require a constant UF6 fuel supply), that's for sure. Initially, given the weight of my craft, I was surprised it even made it off the ground at all on Kerbin. As-is, the thing barely clears the end of the runway on Kerbin due to its weight- but it should lift off much quicker on Duna, thanks to the reduced gravity... I might also install a level deployable-runway or two on Duna using the Extraterrestrial Launchpads mod- if that's allowed (I won't be using it to build the ship, and I probably wouldn't be bringing the necessary Rocket Parts warehouses to build things there anyways- at least not at first, though maybe eventually for future expansion of my operations there- just not for this plane challenge), just for the permanent bases of course.

By the way, one last bit before I cut this post off. The Nuclear Thermal Turbojet Plane I built is capable of using a couple SMALL parachutes in "drogue" mode in level flight- thanks to its very high weight, and thus significant momentum. They don't exert enough torque relative to weight/rotational inertia to tilt the craft, at least not in slow flight close to the ground. This should prove ESSENTIAL to safely landing the thing on Duna, thanks to the much thinner atmosphere at landing altitudes there requiring some sort of way to further slow my craft down in landing, thanks to its relatively high wingload...

I DO have to cut the chutes before the fully deploy in its current configuration however, else the thing will probably still lawn-dart when they open all the way... (though I haven't let them stay open long enough to see if that happens yet- and Duna gravity is lower, so the lawn-dart might be at a safe speed). Since cut chutes obviously can't be re-packed, this means I am probably doing to have to either restrict their use on Duna to landing sites too high up for full deployment before touchdown, or find a way to attach KSP's stock drogue chutes to the thing somehow- which are problematic for their ability to only be connected to a proper attachment port, rather than radially.

OK, I lied, one more thing. I'm looking at building upgraded (larger) versions of the plane, using either 2.5 meter stacks or additional outboard fuselages, to further maximize thrust-wingload ratio. So the design I eventually launch to Duna might not even too closely resemble this one. Larger designs would of course have the benefit of being able to carry more cargo- as it stands, I'm worried about the drag effects of just slapping more than a couple lawnchairs on the thing, to increase its crew capacity (currently only 1- so it doesn't yet meet the minimum requirements- though a single centrally-placed External Command Seat, or larger/additional cockpit, should fix that).

I hope you like the Nuclear Thermal Turbojet idea- and don't consider use of the KSP Interstellar mod cheating (let me know if you do). As is, I'm not even using the highest level of upgraded nuclear reactors (better reactors equal more Thermal Power, and higher core temperatures- and thus more thermal turbojet thrust, though at the cost of higher fuel consumption) for the thing- since I haven't developed the tech nodes for anything beyond solid-core reactors (level #2- upgraded once from the basic version, but not to the most advanced level) yet...

Needless to say, I'd get an even higher thrust return on my mass with an Antimatter Reactor (which I haven't developed the INSANELY expensive tech node for yet)- though the process for refueling that thing's a huge pain-in-the-rear (it requires MASSIVE amounts of electrical power to produce Antimatter, and a Science Lab- which by the way, is huge, and weighs 3.5 TONS). Those things also require antimatter containment tanks, rather than carrying their fuel internally- which makes for an even more unwieldy plane design...

Regards,

Northstar1989

Edited November 13, 2013 by Northstar1989

[1D-1()T]

You seem to have put a lot more thought into this than I did, Northstar1989.

I just found a propulsion method that would work on Duna and made something with big wings.

But, I have thought of a way to get a LOT more points, which I am considering attempting.