zolotiyeruki

Kerbin Circumnavigation 1.2 - Aviator Challenge Continuation

149 posts in this topic

8 hours ago, Jarin said:

So, uh... flying west is apparently substantively different aerodynamically than flying east. Still investigating the actual effects here. But my craft that can hit rapier flameout going east (1752m/s) can barely bust 1730 flying west. Runs out of fuel twice as fast, too.

I tested it out, and got similar results. Well spotted.

Does not look like there is any significant advantage to going west, however. My craft reaches about 1748 m/s going west, so I loaded it with a bit more fuel, and crashed into the runway at 37:55. Half a minute for a proper landing seems a reasonable estimate, which puts it at the same time as my 38:35 eastward circumnavigation. So, I suppose, just go east.

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A long time ago, during a multiple-circle run, I noticed that the aerodynamics changed subtly when I was on the day side of the planet vs night.  I don't know if the game models a difference in air temperature or something, but something made a slight change to the aero when the sun came up.

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9 minutes ago, zolotiyeruki said:

A long time ago, during a multiple-circle run, I noticed that the aerodynamics changed subtly when I was on the day side of the planet vs night.  I don't know if the game models a difference in air temperature or something, but something made a slight change to the aero when the sun came up.

So it looks like we're running into orbital mechanics here. This high and fast, the gravity losses of the slower orbital speed going west are notably increasing the required lift to stay airborne.

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18 minutes ago, Jarin said:

So it looks like we're running into orbital mechanics here. This high and fast, the gravity losses of the slower orbital speed going west are notably increasing the required lift to stay airborne.

All evidence points in that direction, true. I didn't think of it myself, though, so kudos. :)

Reviewing my flights, the westward flight had to use a pitch of about 3.3 degrees above horizontal to maintain altitude, eastward maintained the same altitude with a pitch of 1.7 degrees above horizontal. The speed is roughly the same, the craft the same, and the fuel level is roughly the same. Both readings were taken on the night side.

36 minutes ago, zolotiyeruki said:

I noticed that the aerodynamics changed subtly when I was on the day side of the planet vs night.  I don't know if the game models a difference in air temperature or something, but something made a slight change to the aero when the sun came up.

As far as I know, it does. The air pressure changes slightly depending on the temperature, which changes depending on the time of day. The effects should be very minor. I think the discussion ultimately pointed to this thread, for reference:

 

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@zolotiyeruki

Is there a prize for the smallest circumnavigating aircraft? I have a craft weighing in at just over 10 tons that can make it around ^^

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19 hours ago, NightshineRecorralis said:

@zolotiyeruki

Is there a prize for the smallest circumnavigating aircraft? I have a craft weighing in at just over 10 tons that can make it around ^^

There's no specific category for it, but I'll be happy to make a "Special Achievement" or "Honorable Mention" category for people who would like to tackle it from an unusual angle.

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6XHDZcy.png

Took my English Electric Lightning for a spin 'round the block.  I emptied all the tanks, added just enough OX ballast to one tank to make it controllable if I ran out of fuel, and then filled all the LF with priority to draining the aft tanks first.  I also tucked the main gear inside the fuselage which made takeoff tricky due to the angled wheels.  I'm not sure if that affected drag at all with KSP's aero physics, but it makes the fuselage look much cleaner.  While at cruising altitude the Pilot Assistant mod was used for altitude hold since the stock SAS will just keep pitching up until it settles at stall speed, and nobody's got time for that.

Fullscreen at takeoff to show resources:

Spoiler

UsgsgXI.png

Round the farside:

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Fullscreen F3 and resources at landing:

Spoiler

cZCmVN7.png

 

MET 3:52:43
Max Speed 306 m/s
Max Alt 9001 m
Distance 7,964,988 m

I stayed at altitude until the last minute, expecting to run out of fuel, so I actually overshot KSC a bit and had to land from the east.  I was worried about balling it up after an hour of real time with one shot at landing, but the airbrakes and drogue chutes made it a cakewalk even on the splayed wheels.

pfLt3sz.png

Not a fast time since I stayed subsonic to conserve fuel.  I just wanted to see if the old bird could make the trip.

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I think there needs to be clarification for slow craft. For instance, if my craft only goes 400km/s surface speed, it will have multiple day nigh cycles but only pass KSC once. Also, wasn't there already a 1.2 circum navigation challenge or was that 1.12?

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17 hours ago, macktruck6666 said:

I think there needs to be clarification for slow craft. For instance, if my craft only goes 400km/s surface speed, it will have multiple day nigh cycles but only pass KSC once. Also, wasn't there already a 1.2 circum navigation challenge or was that 1.12?

400,000 m/s would be the fastest thing I've seen in-game that wasn't glitched.  

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On 1/29/2017 at 5:25 PM, macktruck6666 said:

I think there needs to be clarification for slow craft. For instance, if my craft only goes 400km/s surface speed, it will have multiple day nigh cycles but only pass KSC once. Also, wasn't there already a 1.2 circum navigation challenge or was that 1.12?

Assuming you meant 400m/s, we can look at the maximum speed, the flight time, and the screenshots on the other side of the planet as documentation of how many times you went around.

On 1/29/2017 at 11:02 AM, Torquimedes said:

I stayed at altitude until the last minute, expecting to run out of fuel, so I actually overshot KSC a bit and had to land from the east.  I was worried about balling it up after an hour of real time with one shot at landing, but the airbrakes and drogue chutes made it a cakewalk even on the splayed wheels.

Cool!  I've added you to the boards.  One thing I've found that helps with the wheels is to use the Rotate tool in Absolute mode.  You can get the wheels to point true and stand plumb that way, regardless of how they're attached.

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5 hours ago, TheKorbinger said:

y no pizza. :(

I don't know--it was in the original challenge, so I left it in.

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Can we still do this? I would love to earn my first badge!

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Yup, it's still available, if you want it!

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Here's my go at the first level:

Also, got 6 revolutions.

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Wings full of fuel.

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First time around the globe.  HI KSC! *wave*

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After landing - honestly not sure how many times I made it around... I think 4 ish.  I'll have to do the math.  However, the endurance was remarkable: 49 hours and change. (with fuel left over)

Edit -Calculator says 6.019 revolutions.  I did overshoot and come back to land heading 270 - that's the .019 I assume.


7wyyJMs.png
beauty shot

Back to the drawing board for the speed run. :)

Edited by daniel911t
Accidental repeated picture
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Hey guess how much this sucks?! I am a little bit of a noob and was learning about MechJeb's SpacePlane Guidance widget in real time and turns out the Autoland feature isn't too helpful. If it counts for anything, I quicksaved about 15km out and landed by hand. I went to take an F3 screenshot and it said max distance travelled ~17km so I figured that wouldn't be sufficient. I will set this to go again tonight. Also, can we have a version of the challenge where we can use parts mods? OPT, MRS, Procedural wings, etc? I just think my plane is bland. (though I am not what I would call a skilled builder anyway)

nzp09jn.png

 

YWkO5ZB.png

Edited by SapperChop
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On 10/27/2016 at 9:54 PM, zolotiyeruki said:

How are we defining # of circles?  May I suggest your total distance over ground divided by the equatorial circumference of Kerbin ( 3,769,911 m )?

(What's the difference between "total distance covered" and "ground distance covered?", and which of these should be the measure for this challenge?)


Also, do you have to land back at KSC, or is total distance traveled from takeoff to landing/crash in the atmosphere the standard? 

 

Voyager Division

circumnavigator+resized+expedition.png

Circle the globe as many times as you can without landing or refueling.  Score = # of circles.

 

 

 

Edited by daniel911t
Additional question

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It's nice to see this challenge back. Time to re-earn my badge in 1.2.2!

Vehicle used: Condor (Craft file)
Number of circumnavigations: 1
Time: 4:14:53

Assembly
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Resource check before takeoff
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Takeoff 
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Checkpoint: Peninsula east of KSC (I call it Keralonia)
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Checkpoint: Canyon River
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Dark Side of Kerbin 
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Checkpoint: Crater
cnhevGl.jpg

Checkpoint: The Great Desert
94LRUqi.png

Landing
b7vi5Lf.png

Flight Report
r3eBVQd.png

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Attempt Two, I believe I am successful. :)

 

6HzoYBJ.png

 

CYhr1an.png

 

26dBDrG.png

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daniel911t, SapperChop, and Haruspex, you have been added to the leaderboards!  Congratulations!

Quote

How are we defining # of circles?  May I suggest your total distance over ground divided by the equatorial circumference of Kerbin ( 3,769,911 m )?

(What's the difference between "total distance covered" and "ground distance covered?", and which of these should be the measure for this challenge?)

Also, do you have to land back at KSC, or is total distance traveled from takeoff to landing/crash in the atmosphere the standard?

Unfortunately, the mission report does not accurately report the distance covered--it seems to add the rotation of Kerbin or something like that.  For counting circles, the easiest way is to take your total MET, multiply by your highest speed (or, just pick a velocity in the middle of the mission), divide by the equatorial circumference of Kerbin, and round up.

You must land at (or very near) KSC for it to count--half circles don't cut it!

Edited by zolotiyeruki
I messed up the quote
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16 hours ago, zolotiyeruki said:

daniel911t, SapperChop, and Haruspex, you have been added to the leaderboards!  Congratulations!

 

Thanks, how does one add their badge to their signature? 

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I've been working on the velocity challenge with this simple little missile:

YiT1PfV.jpg

but landing is HARD (that's why there's a decoupler and chute!) It'll fly back over the KSC at Mach 5.85 in 37:30 though

Edited by fourfa

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2 hours ago, fourfa said:

Mach 5.85 in 37:30 though

For the purposes of RAPIER science (SCIENCE!) what's your cruising altitude and top speed?

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about 21km and riding engine flameout at 1751m/s.  Sometimes I can throttle down and get a constant speed, but I can't tell if that's actually faster than just full throttle and cycling on and off.

I should probably try less wing incidence and lower altitude for higher speed.  There's a little thermal room left at 21km

(BTW that's with a rule-breaking rear nose cone, but it doesn't seem much different without one)

Biggest problem is throttling down just right during the climb.  It'll explode real quick if it overspeeds too low, but it's really easy to overshoot and set an AP above 100km.  Throttling down to AP at 21km, level off smooth, then full throttle - easily a minute gained or lost there.

Edited by fourfa

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I made a second attempt, this time going for distance!  

The new plane was built around the second most efficient engine, the little Wheesley.  This aircraft required several step climbs, starting at about 8KM, ending at 13,750M.  I really, really, really tried for 14KM, but every time I got there, speed started slowly bleeding off and it was clear I couldn't hold it.

 

m7fADbU.png

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So... now I have to do the math in public and I'll let you decide what seems more accurate for the number of laps:

Time traveled:              2 Days, 5 Hours, 11 minutes (53hrs, 11 min) or, ((53*60)+11)*60 = 191,460 seconds in flight
Highest speed:             267m/s
Approximate distance: 191,460 seconds * 267m/s = 51,119,820m
Kerbin circumference:  3,769,911m
Circumnavigations:       13.56

... however, I landed back at KSC, and only overshot by a few Km.  So a whole number would make sense.

Let me publicly do the alternate:
Ground distance traveled:  33,462,023 divided by 3,769,911 = 8.87 circumnavigations

So... I think the 13 number is closer to truth.  Anybody care to help me figure how far it really was?  (especially in light of the correct answer being known to be a whole number!)

EDIT:  I'm kinda dense - while flying for two days, Kerbin would make two full rotations underneath me.  Depending on how they calculate it, that could remove more than 2 revolutions from my total.  That adds weight to the larger number.

Edited by daniel911t
Kerbin rotates once a day! :)

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