GreenPower Electric Challenge ITS BACK!!!!

[2001kraft]

I present MinIon, the first flying, greenpower Unicycle.

Tried to do it without the added reaction wheel, but coudn't keep it upright.

http://imgur.com/a/J4SRb

Scoring:

Speed 59.3m/s = 55 points

Time 13:33 = 25 points

Mass 1.7t = 13 points

Xenon master: 3 points

Greenpower Elite: 10 points

+anything you want to award for the Unicycle achievement.

Total: 106 points

Did you really just download my design and removed some solar panels, and added control surfaces? Shame on you, ya goob.

Proof:

[wossname]

Congratulations. He has finally been beaten Welcome to 1st place again Juzeris

Congratulations indeed! I doff my flying goggles to you Juzeris. It was a really great challenge and it's always best to have some tough competition to test one's mettle.

And you stuck the landing too. Hmmph.

I have just now moved over to KSP 1.0 (complete abandonment of previous version). So any future efforts on my part will be undertaken in 1.0.

I hope 1.0's shiny new aerodynamics will allow me to claw back a few seconds from you

Edited April 27, 2015 by wossname

[wossname]

Seems that KSP1.0 has severely nerfed Ion Engines. I can barely get a simple go-kart up to 10m/s on the runway. Any ideas?

[ghostbuzzer7]

Yes highly nerfed. At the moment, Im trying to decide the next step to reviving the challenge from ending. :/

[panzer1b]

Ions useless in atmo now, i think we can forget about ion powered anything thats not pure space and or mun rovers ect.

[Pds314]

Yeah... wow. Thrust at sea level of 48 Newtons... That is about enough to make a 13-year-old girl fly with very, very efficient aerodynamics, which is distinctly unlikely.

The engine's TWR at sea level is.... about 1/51. Good F***ing luck getting that to take off.

Edited April 27, 2015 by Pds314

[wossname]

I'm stumped.

Well, lets give it a few days. We have new features to explode explore, and we might find a new way to use ions in a green fashion.

[juzeris]

Well, with the new ISP treatment of engines the new LV-N has a reasonably similar TWR to the old ion, the old Ion had 2kN of thrust and a mass of 0.25t, which equals a TWR of 0.8 (I think?), and the new LV-N has a mass of 3t and thrust at runway level of a bit over 14kN which is a TWR of almost 0.5. However given the lighter aerodynamic drag, and the fact that the TWR will improve once you go higher, it might be a reasonable substitute mechanically.

The flavor would change, of course, as well as the flight dynamics, and I'm not sure about the fuel economy (very little testing performed, but it seems almost reasonable for a ten minute run), but it might work in the spirit of planes with weak engines challenge.

Just a thought.

[Starwhip]

Wow, okay, I thought it might be possible. And it might.

But ain't nobody making it to the Insular Airfield with an ISP of 100. I'm sorry. That's not happening. Especially with a 480 Newton thrust... (or something stupidly small... Was it 48?)

[OdinYggd]

What's confusing me is the new aerodynamics- I need to figure out how much wing is required.

Previously, my single engine craft was capable of leaving the ground at a mere 10m/s, although so far I haven't been able to get past 7m/s or so on the runway.

I'm not ready to give up yet, but this is going to take time to figure out the new flight dynamics.

Gotta take this one step at a time. First we have to figure out how to leave the ground again.

[ghostbuzzer7]

Officially now has two options of scoring either by ions or liquid fuel LV-R1 Engines ONLY.

Edited April 28, 2015 by ghostbuzzer7

[OdinYggd]

Putting an LV-N on the frame designed for my ion powered plane resulted in a very quick liftoff at about 30m/s, mind you an LV-N and 400L 1M tank is a lot heavier than an ion set.

I think the issue is drag. The new parameters mean that you have to do everything you can to keep drag to a minimum.

Edit:

Ion powered flight IS possible once you get off the ground.

http://images.akamai.steamusercontent.com/ugc/44251225245006344/539F923052B81DB620AB99E5E35F4E19A9FB60BC/

I piggybacked this one using a jet-sled to place it at 15km, and once I got a feel for the controls have it simultaneously gaining speed and altitude.

Just at ground level, the max thrust of the ion engine is not enough to overcome the drag of the wing and get it above stall speed, even if there was nothing else attached based on my stall-sled tests. Under the new aerodynamics model, airfoils must exceed approximately 20m/s just to support their own mass let alone provide any lift to a load, while the best ion-only drives I've seen are unable to exceed approximately 10m/s on the ground.

I think my next attempt is going to use an ion-powered catapult to try and accelerate the craft up to liftoff speed, but even then it will quickly slow back down and stall on ions alone I think

Edited April 28, 2015 by OdinYggd

[juzeris]

Officially now has two options of scoring either by ions or liquid fuel LV-R1 Engines ONLY.

LV-1R, are you SURE about that? I've more than halved my time on the first attempt, and I'm ascending out of habit, I have no clue what I'm doing (yet) and it's definitely far from optimal (2:27).

Ion powered flight IS possible once you get off the ground.

Well, once you get up there where the pressure is low, ion engines are close to what they used to be, so it will probably fly even better due to the changed aerodynamics. Down on the ground they provide almost no thrust however. It's definitely not the drag but the atmospheric Isp, which now properly produces less thrust instead of higher fuel consumption.

[ghostbuzzer7]

Im pretty sure I still want the LV-R1's division in this. As you can see, you think outside the box . People say I only need two of them, you say you mean't two.... hundred. Anyways, probably adding a real with the ions that you may use sepratrons I to get into thinner atmosphere. Would you be willing to test that out for me Juzeris? Btw great submission.

-----Edit-----

Actually, you build a rover that releases it in the air as said by OdinYggd..... Rule changing.

----Edit---- Im going to try the new rules. Must have a rover to deploy glider. Hopefully it works. Juzeris Can you test that for me. Not that thing above.

Edited April 28, 2015 by ghostbuzzer7

[juzeris]

Well, I ran some tests on the ion engines just for you, but the videos are pretty boring, I'm just dropping ion powered probes from orbit. So here come the test results (sound warning).

tl;dr I cannot figure out a way to make ion engines work for this challenge in 1.0. Unless we can have 3km high launch clamps (we can, but that's a very niche market).

less tl;dr:

I don't see rovers working, ion engine problem is not speed, but altitude. Mr. OdinYggd tested it at 15km as you can note, and at that altitude they run at 98% power or so, which is perfectly fine.

The lowest they miiight be able to work is about 3km up in the sky, and that's pushing it, and starting from that altitude you can probably just glide to the old airport (not tested!).

-----BEGIN NUMBERS-----

The main testing takeaway is that the ion engines run at almost full power at 20km up, still have 75% of their power at 8.5km up, 50% power at about 5km up, 25% at 2.35km up or so, 10% at 1.15km up, 5% at 500m and only lower after that. (Or we could just plug the exponential atmospheric pressure gradient into the unity interpolation function of 4200 isp in vacuum and 100 at sea level, but, eh, not enough explosions).

Now, everyone's his own engineer, but from some more testing, a streamlined craft (cart) at 0.1 TWR will reach 30m/s by the end of the runway, [email protected], [email protected], [email protected], [email protected], [email protected]. I don't know what the new lift formula is, but I don't think it's reasonable to ask a plane to lift off at less than 40, which would require a TWR of about 0.2. From my previous entries it's very hard to push the engine mass ratio above 75% for ion planes, so that would require the engines of 0.266 or so rounded, which would be 1/3 of the total. Ion engines have 33% power at 3km altitude above sea level. A rover will not help, as normal rovers can reach only slightly over 23m/s on level ground.

Even a plane boosted to 50m/s will not have enough energy to climb to the altitude required to maintain flight with ion engines, as initially the ion engines will not be able to maintain velocity even in level flight.

-----END NUMBERS-----

EDIT: There might be other ways to get there using just electricity though...

Edited April 29, 2015 by juzeris

[Starwhip]

Im pretty sure I still want the LV-R1's division in this. As you can see, you think outside the box . People say I only need two of them, you say you mean't two.... hundred. Anyways, probably adding a real with the ions that you may use sepratrons I to get into thinner atmosphere. Would you be willing to test that out for me Juzeris? Btw great submission.

-----Edit-----

Actually, you build a rover that releases it in the air as said by OdinYggd..... Rule changing.

----Edit---- Im going to try the new rules. Must have a rover to deploy glider. Hopefully it works. Juzeris Can you test that for me. Not that thing above.

What, Juzeris has to test all the things?

I'm gonna import my Ion Sail, see how it performs. I doubt it will work, but then again, it is vastly different in design from the others here that I have seen so far.

Then I'll try pure Ion power. Then the rover.

EDIT:

Okay, it took 3 minutes to get to the end of the runway, that ship ain't workin'.

Next, Ions, 1.0 style.

EDIT2:

Oh, dear...

Zero TWR, are you kidding me?

AGAIN:

Okay, so it is REALLY a priority to get higher... look at what a few thousand meters does.

Edited April 29, 2015 by Starwhip

[wossname]

Hmm, the LV-1R "Spider" engine category (check the spelling on the OP) just got me to the Insular Airstrip in less than 5 minutes without any real effort or any real wings. Perhaps this challenge should be restricted to a maximum of 2 or 3 spider engines.

I will not submit my entry in this case since I dispute the rules

[ghostbuzzer7]

Officially tested and modded by me. You must download that modded part because 1.0 basically makes ions useless in atmosphere. Yes it is possible. Once again proof of concept.

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All crafts must still remain stock. Old leaderboards will be merged with the new ones depending on how outrageous designs can get such as Juzeris and wossname. Happy gliding *ISP is better, fuel effieciency is not at all, need a lot more solar panels to keep them going, taking off is hard but once in the air, ascend slowly to prevent stall. From high altitude ISP raises drastically because ASL/VAC ratio.