The MachingBird Challenge!

[nicky4096]

the superbird challenge or something like that maybe?

but seriously tho, im still having great fun

edit: maybe the machingjet challenge?

i suck at coming up with names.

[Skyhawk]

Yeah, it's great to see you're designs and such, by again, no hope of ever getting on a leaderboard (I tried months ago), and some mode might just decide to lock this thread at some point. I'm just saying it's probably time to let old birds rest, and move on to something else. I'm awful with names to but I'll try to think of something creative.

in the meantime, just keep on pushing, you'll break the record eventually, even if no one sees it on the board.

[capi3101]

Well, if y'all are calling it...no harm in putting mine up then.

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Stock, unmanned, no mods used (though plenty installed). Final speed 2246. Should've tried a little harder - could've got a True Machingbird with another 50 m/s. If the leaderboard was being updated...

"Phoenix Challenge"? This does seem to be one that keeps being brought back from the dead...

[numerobis]

Skyhawk: Every new jet challenge gets a bunch of posts saying that it's already been done, pointing at *this* thread.

I don't see the harm in keeping this one around. So you can't get on the leaderboard; who cares?

[nicky4096]

nice one capi3101!

i agree with numerobis. but go ahead skyhawk if you like

but! 2375 m/s! i actually did this 2 days ago but had horrid internet so

stock, manned, 136 intakes i believe. THIS time i ditched the monoprop

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Edited November 22, 2014 by nicky4096
misspelled 'like'. although i dont know why you'd care. =)

[nicky4096]

PS, skyhawk, if you do make a new machingbird challenge, then i would include categories for airhoggers, 1:1 intake/engine planes, planes with decoupler stacks like discus', and infinigliders

if you like i can do it.

EDIT: and a category for orbital trebuchets like Pbhead was gonna build!

EDITEDIT: and a category for MJ planes, and a category for B9, and a category for FAR, and a category for...

Edited November 23, 2014 by nicky4096

[Pds314]

I think we should reset the FAR entries, seeing as FAR jet speed has been reduced to 1800 m/s, and thrust had been halved. Of course, the problem is that highly aerodynamic vehicles can reach nearly 1800 m/s, start falling back down, and then exceed 1800 m/s in the dive.

[nicky4096]

shoudlnt we start a whole new leaderboard?

[Wanderfound]

I think we should reset the FAR entries, seeing as FAR jet speed has been reduced to 1800 m/s, and thrust had been halved. Of course, the problem is that highly aerodynamic vehicles can reach nearly 1800 m/s, start falling back down, and then exceed 1800 m/s in the dive.

Which is where DRE comes in.

I'm actually finding the dive technique to be not that useful. You lose more to drag than you gain from gravity; you're coming down at much more than terminal velocity. Diving aids acceleration rather than top speed.

I haven't had anything over 1,800m/s on FAR jets alone; current best is this:

Edited November 23, 2014 by Wanderfound

[nicky4096]

but DRE isnt a requirement for FAR is it?

i have never used FAR so i apologize if im being dumb.

i gotta say though wanderound, that is an epic fireball.

this probably is different in FAR, but in stock diving is VERY useful. i got to 2375 by orbiting until i ran out of fuel in my droptanks, dropping those, and on those last 45 units of liquid fuel did a speed run coming back into the atmo, while getting a boost from gravity

EDIT:is patvin a BadS? because he looks like it

Edited November 23, 2014 by nicky4096

[Hodo]

but DRE isnt a requirement for FAR is it?

i have never used FAR so i apologize if im being dumb.

i gotta say though wanderound, that is an epic fireball.

this probably is different in FAR, but in stock diving is VERY useful. i got to 2375 by orbiting until i ran out of fuel in my droptanks, dropping those, and on those last 45 units of liquid fuel did a speed run coming back into the atmo.

Not required but it is like eating Oreos without milk or cake without frosting!

[Wanderfound]

but DRE isnt a requirement for FAR is it?

i have never used FAR so i apologize if im being dumb.

i gotta say though wanderound, that is an epic fireball.

this probably is different in FAR, but in stock diving is VERY useful. i got to 2375 by orbiting until i ran out of fuel in my droptanks, dropping those, and on those last 45 units of liquid fuel did a speed run coming back into the atmo.

FAR and DRE are independant of each other, but they go very well together.

The big difference in stock is that your engines keep pushing you throughout the dive; in FAR, jet thrust drops to zero before Mach 6.

You might get a good dive in FAR if you came in from orbit, but you'd need rocketry to get up there without burning all of your existing lateral speed in the climb.

BTW, follow up pic:

[nicky4096]

but then just having a new leaderboard works fine right?

thanks for explaining though

EDIT: wanderfound, that is an even more epic fireball, however you are going slower, which makes it 16.43% less epic. JK

im starting to wonder what these fireballs would look like in real life

Edited November 23, 2014 by nicky4096
mispelled "thanks"

[numerobis]

My favourite trick in this thread was to bottle up a bunch of IntakeAir, and use it at apoapsis. At Ap you're going about 1km/s, so that's the most efficient point. If you burn prograde you'll just raise Pe, but if you burn downward you can get an orbit with much higher speed at periapsis. Then you shed everything except your cockpit, to minimize the drag as you re-enter. I got over 2500 m/s surface horizontal with that

Of course, if you have control surfaces, you can infiniglide your way to a solar escape velocity.

[nicky4096]

My favourite trick in this thread was to bottle up a bunch of IntakeAir, and use it at apoapsis. At Ap you're going about 1km/s, so that's the most efficient point. If you burn prograde you'll just raise Pe, but if you burn downward you can get an orbit with much higher speed at periapsis. Then you shed everything except your cockpit, to minimize the drag as you re-enter. I got over 2500 m/s surface horizontal with that

Of course, if you have control surfaces, you can infiniglide your way to a solar escape velocity.

yeah, but as soon as you close your intakes, they start losing air, so you have to have RIDICULOUS amounts of intakes (you needed 4k for 2 mins of run time). it's a cool trick, but as far as im concerned, pretty part count heavy.

of course i might be being dumb again and the intakes might actually not lose air which would be awesome

[hoioh]

I just had to try this! Got up to 2342m/s upon reentering the atmosphere:

http://imgur.com/a/jzm4c#0

100% Stock btw.

From this experience I did think of a new challenge and I wonder if that's possible/tried before: would it be possible to obtain so much speed in atmosphere that you can create and maintain an orbital trajectory? Or in other words: can you put a craft in LKO with just jet engines?

That should definitely not be possible in the real world, but I'm not that good and just trying this challenge got me a apoapsis of 240k and a periapsis of of 42K that's pretty close, isn't it? I'm certain one of the die-hards could pull it off without using infinigliding or somesuch "cheat", right?

Edited November 28, 2014 by hoioh

[nicky4096]

nice plane man! some tips to make it faster:

1. use only 1 jet engine. if you dont have enough speed to lift off with only 1, then use 2+ but drop all of them but one at like 30-40 km or so..

2. get rid of the wings!

3. MOAR INTAKES!

4. use a smaller fuel tank for your final run, and then to get somewhere, use droptanks. LESS WEIGHT!

about getting to orbit, its not possible without bottling up intakeair like numerobis said (i still cant figure out why the air goes away while they are closed tho. maybe the engine is draining it or something)

im actually surprised you got to 2342 m/s with that low a periaps/apoaps! my 2375 m/s run ended with a periaps above 50 km and an apoaps WELL above 400 km. i believe lesbiotic got even higher.

hopefully this helps

Edited November 30, 2014 by nicky4096

[hoioh]

I tried with one engine, but didn't manage to get over 2300 m/s with that, that's why I went for 2 on that attempt, hopig it would get the thing to go faster. Twice the thrust and all that, but it turns out that the engines just start to crap out after a certain speed, or maybe I just tend to fly too high.

I tried moar intakes, but I get clipping issues like below. The intakes tend to attach to each other and function like one of them springs that walks down stairs. Eventualy the physics .... up and itn tears it to shreds...

https://dl.dropboxusercontent.com/u/2935674/Kerbal/2014-11-28_00090.jpg

I'll try it withou wings, curious how that turns out though, I'm just managing to fly planes barely. Too much hassle to build a spaceplane and land it, so I tend to lean towards single use rockets.

Smaller fuel tank is definitely an option!

About the apoapsis and periapsis, on the first run I got up to 240K, but the highest I got thusfar was well over 300K with lower speeds. I figured that meant I was wasting energy on going up rather than forward and tried to reduce my vertical velocity to as close as I can to 0 (which is a lot easier with MechJeb than without.) And then I managed to squeeze this speed out of it. So maybe if you attempted a similar strategy with your craft you'd be able to break 2400 m/s. You never know, right?

[nicky4096]

the engines in KSP produce NO thrust above or at 2400 m/s, as i understand it.

if 2 works better for you, then go ahead, its just that ive never gotten fast with more than 1

on my 2375 m/s run, i did do lots of periaps kicks (pointing down once in front of periaps). the problem is, above a certain point, at least for me, the engines just dont produce enough thrust to bring up periaps. so you have to point basically strait down, which means less intakeair, which means less thrust, which means youre just wasting energy.

at least for me

about intakes, try pinalallo's technique:

start with an octo struct.

place the desired amount of inverted cubic struts into the octo strut (if you want 8 intakes, then clip 8 in)(switch symmetry on and off to get it to clip)

stack as many intakes as you have cubic struts onto the octo strut. i use 8 intakes per octo strut

SPAM AWAY! just make sure the octo strut units dont clip into each other.

if that makes any sense

[numerobis]

about getting to orbit, its not possible without bottling up intakeair like numerobis said (i still cant figure out why the air goes away while they are closed tho. maybe the is draining it or something)

The engine uses air from all intakes, whether they're open or closed. To bottle up the air you need to click the triangle that you see when you right-click the intake -- that makes it so that engines aren't allowed to use the air that's stored there.

[scifi6546]

here is my ship it is probably the lightest ship submitted...

here is a link to the ship on igmur http://imgur.com/a/LU0Bz

[nicky4096]

The engine uses air from all intakes, whether they're open or closed. To bottle up the air you need to click the triangle that you see when you right-click the intake -- that makes it so that engines aren't allowed to use the air that's stored there.

that makes sense. i gotta try that!

thanks for explaining

[nicky4096]

hoioh - its easily possible to get something to LKO on jets alone.

next step - geostationary orbit with only jets XD

i only used 10 radial intakes or something, but they were all only like half full when i closed them.

pics:

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speed at periaps was only 2275 m/s, you really should point strait down.

[hoioh]

Nice contraption, Nicky, love the wings!

I don't really get your description of the intake clipping, maybe you can show me a couple pictures?

Currently I'm just placing a cubic strut and attaching an intake to the attached end (I use alt-F12 clipping, easier that way). Then I copy-paste that strut-intake combinationall over the place without stacking it onto any other parts but the structual ones.

The moment I'm placing one on top of another the physics break and it just vibrates into pieces.

I managed to build a new plane with about 30 intake air last night, but didn't manage a speed above 2325 m/s even using the same craft as before, just with more intakes didn't help to increase my speed. So maybe instead of adding more I should actualy remove some to get a better thrust to weight ratio, or maybe I had the perfect ratio to begin with, considering your amazement at my speed achievement, who knows eh?

Also tried the no-wings thing, but that I really can't fly. It becomes uncontrollably unstable once I try to drop my nose after about 12k altitude. This basically happened all the time, no matter how I tried. Without the wings, I'm basically lost.

[nicky4096]

ill get the link for the intake in the sec. pinalallo posted it on the K-prize thread.

FYI debug menu clipping is considered cheating by henge, but hes not looking anyway

intakes are part of the trick, but not all. how big is your tank? i usually use an FTL-100 for my speed run. you need as little weight as possible. try the mk1 lander can as a cockpit (drain the monopropellant too!)

if the plane becomes uncontrollable without wings, spam reaction wheels (i like to use 4). if they weigh you down, drop them for your speed run.

hope this helps

the sweet intakes spot for me seem sto be 25.6 intake air or 128 intakes.

here is pinalallo's technique: K-prize thread, page 53, post #524. i dont know how to link to posts, so heres the url for page 53: http://forum.kerbalspaceprogram.com/threads/11214-The-K-Prize-100-reusable-spaceplane-to-orbit-and-back/page53