Ion glider collier trophy!

[Yakky]

Here's an entry using FAR, so it may not qualify (but I would argue FAR makes it harder).

No control surfaces. Gentle turns are possible using the Probodobodyne core's torque. I got to about 32.4km before I ran out of daylight (after stupidly going in a straight line since takeoff). Next time I'll circle up to 25 km or so before starting the final speed run.

Just after takeoff:

Good progress with lots of fuel left:

Oh no! Out of daylight!

[Yakky]

OK, a moderately better result. This time I got to 41.6 km and 1680 m/s over land (slightly over 1800 in orbital reference frame). I still ran out of sunlight before I ran out of xenon.

The trick is going to be accelerating to orbital velocity before running out of sunshine. I'm not sure that's possible. For this attempt, I first flew west until I go to the edge of the sunlit sky at about 25 km and 450 m/s, then turned around and went in a straight line as far east as I could go. Darkness ensued before the xenon was used up.

Taking off from KSP and then heading west:

Turning around to head east again:

Passing back over KSP at about 30 km and going respectably fast:

Near the top:

So..... close..... to..... orbit!

Best speed and height recap:

[GoSlash27]

Yakky,

My longer duration flights, I just wait until late afternoon and take off heading west. You can get halfway around the planet before you run out of daylight.

As for your entry, it will have to go in its own category, since FAR aerodynamics are so radically different from stock.

Best,

-Slashy

[GoSlash27]

Laie,

That's a cool graph! That sort of datalogging would be really useful for R&D purposes...

You really need to have a low enough wing loading to carry you through "the wall" in that graph to a little over 30 KM. After that, your climb rate picks back up. And you also need enough thrust to accelerate you as quickly as your terminal velocity is increasing. But you also need enough fuel to give you the time for all that to happen, and all 3 are mutually exclusive, so it's a balance thing. My best entry thus far has 8 wings, 3 engines, and 5 xenon tanks. You might want to try experimenting with that ratio and see how it goes.

Anywho, 22.5* is the optimal AoA for a bare wing from a lift vs. drag standpoint, but it's not necessarily the best for an encumbered wing seeking best climb rate. 17* was pretty good for that particular craft according to empirical testing, but not necessarily a "recommendation". It's merely the profile that I used, so if you were to download my craft and verify it's results... you knew how I flew it on that submitted run.

I have since altered my flight profiles, and don't fly a fixed AoA anymore. Now I look to match a percentage of terminal velocity at benchmark altitudes, dependent on the craft's t/w ratio.

Best,

-Slashy

Edited August 10, 2014 by GoSlash27

[Yakky]

OK, I made orbit with plenty of fuel to spare! It involved careful craft design AND a careful flight plan that transitioned from a polar climb-out to a giant eastward turn at the end. Probably the most complicated continuous burn I've ever had to do. (And as a reminder, this was with FAR so not technically meeting the "no mods" rule. But I'm pretty sure it could be done without FAR if someone wants to try.)

A couple of "aha!" moments helped me figure out how to do it:

The first "aha!" moment was realizing I could use a carefully positioned polar orbit so that the sun would never set. That freed me from having to worry about running out of daylight. I took off from the runway a little before sunset, turned left, and headed north.

The second "aha!" moment was to use the very last wisps of atmosphere to make a high-speed turn to start heading east again along the equator. That allowed me to get a final kick into orbit from the usual 200 m/s or so of Kerbin's rotational speed. At high altitude and high speed, I started the turn a little below the north pole and didn't finish it until I was a little south of the equator.

Here are some screen shots:

Climb-out more or less like the posts above until 20 km. Here heading north toward the pole:

Over the pole at around 30 km. Soon it will be time to start the big left-turn that will take me well past the equator to complete.

Past the pole, heading south, and starting to turn left. Note compass heading change.

Still turning.

And still turning. At this point it's looking pretty good.

Here's where I finished the turn. I'm now so high and going so fast that the trajectory is pretty much unchangeable.

It's more a spaceship than a glider now. Inertial forces start dominate aerodynamic forces. Gets a bit hard to control in the upper 40's kms but the probodobodyne core has enough torque to keep things more or less under control.

Gaining speed to boost to a nice apoapsis around 250km. My periapsis is still within the atmosphere. It will soon be dark and I'll have to coast until there's solar power again.

After the sun comes up again, a small burn near apoapsis raises the periapsis up out of the atmosphere. We are in orbit!

Screen grab confirming orbit achieved:

Edited August 11, 2014 by Yakky

[Laie]

Laie,

That's a cool graph! That sort of datalogging would be really useful for R&D purposes...

It is. Many things I do wouldn't work half as well if it wasn't for logging and plotting data. That's just a kOS processor. Logging flight data to a file is just three lines of code; and of course, kOS is much more versatile than any prefab data recorder. For display purposes, I use Gnuplot.

kOS also flies the plane; it strives to maintain a set percentage of terminal velocity (though around 15-20km, terminal velocity climbs faster than I allow kOS to pitch up). The ion flights run on autopilot while I'm otherwise occupied -- I certainly would have given up long ago if I had to babysit them myself.

My best entry thus far has 8 wings, 3 engines, and 5 xenon tanks. You might want to try experimenting with that ratio and see how it goes.

10 resp. 14 wings, one engine, four tanks. Though the key feature is the tilted engine: if the wings can't provide enough lift, maybe the engine can help out? Having it point down by ~15° helped a lot -- otherwise, these flyers would have stalled much sooner than they eventually did.

As to flight path, I strongly suggest going east. Eventually, orbital velocity will matter; and going east or west makes a 300m/s difference. I'm already high up and reasonably fast when I fly into the night; it takes me about 25k units of batteries to last until dawn. That's doable with physicless parts, though frankly, I just cheat. I may build a stock craft when and if I can expect it to work; until then, I use stronger batteries and weightless reaction wheels (for kOS' sake).

[Yakky]

Polar orbit means no nighttime if done properly. Helped me a lot!

[GoSlash27]

10 resp. 14 wings, one engine, four tanks.

What's "resp."? And yeah, that t/w ratio is way too low. I think tsevion did some experimenting along these lines and found that you need a minimum of .42 t/w to clear the wall and reach orbit. My findings generally agree with that.

Though the key feature is the tilted engine: if the wings can't provide enough lift, maybe the engine can help out? Having it point down by ~15° helped a lot -- otherwise, these flyers would have stalled much sooner than they eventually did.

Funny, I found the opposite; about 15* up But of course... none of us have reached orbit yet.

As to flight path, I strongly suggest going east. Eventually, orbital velocity will matter; and going east or west makes a 300m/s difference. I'm already high up and reasonably fast when I fly into the night; it takes me about 25k units of batteries to last until dawn. That's doable with physicless parts, though frankly, I just cheat. I may build a stock craft when and if I can expect it to work; until then, I use stronger batteries and weightless reaction wheels (for kOS' sake).

The reason I work west on the longer flights is because I haven't yet reached orbital velocity in any direction. I figure if I can hit 2Km/sec heading west, then I can slap some batteries on it and head east. Until then, not worth the headache.

As it stands, my current ratio of wings/engines/fuel don't have enough fuel/engine for it to be an issue. I can launch east and run out of fuel before daylight, and I always go east when I can, since turning is inefficient.

Best,

-Slashy

Edited August 11, 2014 by GoSlash27

[ihtoit]

Simple question: will the delta-deluxe with locked control surface be acceptable? It's called "winglet" after all.

Better question: I've heard about infiniglide before and suspect this rule is meant to prevent it. I don't quite know what it is or how it works, though. Would you explain what this rule really is about?

Infiniglide is a physics glitch in KSP that basically allows you to power an aircraft to ridiculous speeds without consuming fuel, instead using the flapping motion of multiple active control surfaces. This means you can build stupidly light. FAR negates this effect. Infiniglide can be used on ion gliders to produce greater thrust than the engine itself (I've been accused of it, still waiting for a proof that two small ACS panels can actually power a 3 ton glider to orbit...)

[Laie]

What's "resp."?

Respectively.

The reason I work west on the longer flights is because I haven't yet reached orbital velocity in any direction. I figure if I can hit 2Km/sec heading west, then I can slap some batteries on it and head east. Until then, not worth the headache.

In a way, you're right -- if you can't get to orbit, why bother. But if altitude records are a worth goal in and of themselves... once you make it through the 30km hole, climb rate recovers not because of, but despite the wings. I presume. MOAR WINGS works better until then (well, to some extent) but the recovery seems to be based on TWR, so additional wings are starting to bog you down. Also, I can pitch down slightly without hurting the climb rate. Hence I believe that orbital velocity is becoming important at that point.

If I am right, there should be a noticable runaway effect. If you barely make 40km going west you might reach orbit going east.

Update: 34.3km and 1290m/s on two engines, twelve wings, five tanks. Placing lift over thrust may take me as far as you, but it doesn't seem as if I could get much further.

Edited August 12, 2014 by Laie

[GoSlash27]

Respectively.

In a way, you're right -- if you can't get to orbit, why bother. But if altitude records are a worth goal in and of themselves... once you make it through the 30km hole, climb rate recovers not because of, but despite the wings. I presume. MOAR WINGS works better until then (well, to some extent) but the recovery seems to be based on TWR, so additional wings are starting to bog you down. Also, I can pitch down slightly without hurting the climb rate. Hence I believe that orbital velocity is becoming important at that point.

If I am right, there should be a noticable runaway effect. If you barely make 40km going west you might reach orbit going east.

Update: 34.3km and 1290m/s on two engines, twelve wings, five tanks. Placing lift over thrust may take me as far as you, but it doesn't seem as if I could get much further.

I concur with all of your observations, but disagree with your hypothesis about launch direction. There's no altitude advantage or disadvantage either way, but when you transition to orbital velocity it reads 349 m/sec faster. (edit) My current record flight was conducted eastbound. (/edit)

That's a very respectable speed and altitude! You should submit an entry for your spot on the leaderboard.

Best,

-Slashy

Edited August 12, 2014 by GoSlash27

[GoSlash27]

Yakky,

Congrats on reaching orbit. I'll update your mention on the leaderboard to reflect it. Do you have a name for this craft? Also, what was the final apoapsis/ periapsis?

-Slashy

[Laie]

This is not a stock craft.

(great, now I've got Johnny Rotten ringing in my ears: It's no stock craft, it's no stock craft... )

Anyhoo, that's not merey a kOS core, but also a bottomless power supply and a reaction wheel, at zero weight. I have no qualms about the battery (it just saves a lot of parts, that's all) but would the probe core alone suffice to control the plane? I haven't tried, nor will I.

No craft file, as the design is so obvious and straightforward: 12 wings, four tanks, two engines. Nothing is tilted in any way (well, the wings are swept forward to make them as straight as possible).

Flight profile:

maintain 31% of terminal velocity

pitch up gently, no more than about on degree per minute (so at ~15km, airspeed will increase faster than you pitch up).

stop at 22 degrees.

the plummeting climb rate will recover briefly somewhere around 25-26km. At that point, lower the pitch to 21.5 degrees.

wait until fuel runs out.

Edited August 12, 2014 by Laie

[GoSlash27]

Laie,

You should submit a stock version of that glider. I've run them that big with a probe core.

Best,

-Slashy

[Tsevion]

I made a video examining exactly why using locked control surfaces as wings is broken, I thought it might be relevant.

And yes, I actually started this video when we were working on this and took this long to actually put it out... I'm that slow.

[GoSlash27]

Tsevion,

I became convinced of that during our time working on the Eve SSTO effort, which is why the rules of this challenge are so strict for control surfaces.

One control surface for use as an empennage. It must be locked and must be oriented vertically. This serves to make infinigliding (or even just a competitive advantage) impossible for this challenge.

This is borne out by the result; nobody has as yet managed to achieve orbit in this challenge, though several people have achieved orbit in other challenges using locked control surfaces.

Best,

-Slashy

[spaceman1999]

*Snippity ...nobody has as yet managed to achieve orbit in this challenge... Snip*

Yakky made it with FAR.

[GoSlash27]

Yakky made it with FAR.

"With FAR" being the key phrase. The rules call for stock aerodynamics, and that's why.

Best,

-Slashy

Edited September 26, 2014 by GoSlash27

[Tsevion]

Tsevion,

I became convinced of that during our time working on the Eve SSTO effort, which is why the rules of this challenge are so strict for control surfaces.

One control surface for use as an empennage. It must be locked and must be oriented vertically. This serves to make infinigliding (or even just a competitive advantage) impossible for this challenge.

This is borne out by the result; nobody has as yet managed to achieve orbit in this challenge, though several people have achieved orbit in other challenges using locked control surfaces.

Best,

-Slashy

Yeah... I figured you'd already reached the same conclusions. I mostly added this here for anyone else wondering on the strictness of limiting control surfaces... also some of the behavior is just funny. My particular favorite I when they're reversed... the results are just hilarious.

[Monthar]

Why no batteries?

[GoSlash27]

Why no batteries?

Oh, batteries are legal. You just get a bonus for not using them. The reason was to encourage development of legal entries for a previous challenge; Reach for orbit

Best,

-Slashy

[Monthar]

Here's my first manned attempt. No control surfaces of any kind, no batteries and no RCS (although I forgot to drain the monoprop from the command module). The vertical stabilizers are Tail Fins. Shortly after the last screenshot the aircraft started an oscillating roll that I couldn't recover from and ended up crashing. I know it got above 7300m before losing altitude, but I was too busy trying to regain control to remember to take a screenshot. I'll likely try again after some redesigning. I'm still happy with this attempt since it is the only legal manned flight for this challenge so far.

7262.1m (according to the flight engineer) altitude and 48.4m/s speed

Edited September 27, 2014 by Monthar

[GoSlash27]

Monthar,

Well done! Do you have a name for this entry?

Best,

-Slashy

[Monthar]

I named the ship Ion Glider 2 when designing it, but let's go with The Red Baron since it's a tri-plane and it looks kind of evil.

[GoSlash27]

I named the ship Ion Glider 2 when designing it, but let's go with The Red Baron since it's a tri-plane and it looks kind of evil.

I've updated your entry and I look forward to your next run

Best,

-Slashy