Micro-challenges for all! (Continuation of Newbie Central.)

[sturmhauke]

What about the altitude though? Don't the Panthers get starved for air at like 18km or so?

[AeroGav]

3 minutes ago, sturmhauke said:

What about the altitude though? Don't the Panthers get starved for air at like 18km or so?

If you look on the Wiki,  all these engines' thrust and altitude curves are on there but you have to click on the Spoiler icon.

Yeah, the Panther loses power rapidly after 14km and mach 2.5,  but by that point your RAPIER is making 8x normal power, so it doesn't matter all that much.    From what i can tell,  your craft has a gross weight under 40ton,  a single rapier should be able to push that to mach 4.5 easily in level-ish flight at 20km or so,   but obviously a single rapier woudl not have enough thrust below mach 1 to get you supersonic, or even take off.

[sturmhauke]

Yeah it's 37.8t at launch, 29t on landing. That gives it a fuel mass used of about 23%. Between dumping some extra fuel and swapping in a couple Panthers, I could probably get cargo space for a small probe in there without changing the lines too much.

[AeroGav]

OK,  I had a play with that sleek looking mk2 from Teddy_Radko,  https://kerbalx.com/Teddy_Radko/SX-60B
I eventually was able to make it into this -

Spoiler

.. 

 

2 Junos, 1 RAPIER (air breathing only) 2 NERVs.   Original a/c is 3 RAPIER with 1 hidden NERV clipped into central RAPIER.    Even though the mk2 body is actually only a small part of the ship,  there's a whole bunch of cylindrical tanks which a chem ship needs but add too much drag for a LF.      Despite removing the RCS ports and adding extra strakes, the supersonic lift/drag was horrific, 1.2 to 1.     You could chuck on more RAPIERs to get TWR over 1 to compensate but at that point you might as well just strip off the wings and make it vertical launch ! 

So,  I angled the wings up about as much as i could without spoiling the looks.  This keeps fuselage closer to prograde and reduces its drag -

The trick here is to angle the front wings up slightly more than the rearmost, so they start to stall first.   This is also has the effect of making the airplane adopt a slight nose up attitude when there is no control input, but it resists going too far as the front end gets into "diminishing returns" before the back end does when AoA rises further.      The airplane was still draggy however.   I could add more jets, but it could not be able to sustain itself on 2 nukes when they flamed out.   then i discovered hidden part.      The original file contained a RTG that had been clipped inside the fuselage, but in fact the rear fuselage was attaching to this RTG rather than the attach node of the fuselage section in front.     So you had  a mk2 attach surface, joining to a  tiny size part (the RTG) , then the other end of the RTG was hooked up to a mk2 again.  The mismatched nodes were causing a lot of drag. 
Even after all these fixes, it's still a bit of a barge.   Here's the excess thrust chart with the NERVs off 

Spoiler

 

... and here it is with them on -

I kept this screenshot on my other monitor when flying it to orbit, and thus was able to reach space.   Even then , the lift to drag numbers were poor.    It could go over 2 to 1 , but spent most of its time at 1.8 to 1 while supersonic.   The above graph indicates that the NERVs should not be able to sustain level flight on their own, but by the time the RAPIERs quit you're going at a substantial fraction of orbital velocity, which greatly reduces the spacecraft's apparent weight, which enables it to do the remaining acceleration over 30km where drag is low.       My other designs  like the Sparrow get lift to drag of  3 point something or even 4 point something to one at hypersonic speed.

My version here https://kerbalx.com/AeroGav/SX-60L

[sturmhauke]

I made a nuclear jet-powered SSTO. There are only two nuclear jets in the NF suite (Aeronautics pack) - the "Fireflash"  for atmo only (any atmo, weighs 12.9t), and the "Project Eeloo" multimode that can burn LF also (weighs 14.9t).  The other nuclear engines are all rockets and come in the Kerbal Atomics pack.

Anyway, I used the Project Eeloo engines along with the Mk IV Spaceplane pack, Aircraft Plus (just wheels I think), and Tweakscale, to come up with this:

Spoiler

Might be practical if I can make some improvements, but right now it flies like a tank. It weighs 159t on the runway and has trouble getting up to speed, but once it gets going it can get to orbit with enough dV for Munar insertion. It also needs doodads like reaction wheels and/or RCS, electrical, radiators, that sort of thing.

[PrvDancer85]

Hey,

This goes to orbit and has About 2700dv left in lko. It flies quite nice and has no problem at reentry even with half the fuel left.

Spoiler

I realy like this thing but i'm alittle confused why it works with just one airintake.

[sturmhauke]

56 minutes ago, PrvDancer85 said:

I realy like this thing but i'm alittle confused why it works with just one airintake.

You only need 1 shock cone per 4 Rapiers or Whiplashes. The intake spam thing stopped being useful sometime before 1.3 (I dunno exactly, that was before my time). With the current aero model, too many intakes just creates unnecessary drag.

Anyway, nice work! It's probably the cleanest-looking solution so far.

[PrvDancer85]

1 hour ago, sturmhauke said:

The intake spam thing stopped being useful sometime before 1.3

Anyway, nice work! It's probably the cleanest-looking solution so far.

I remember bewing wrote something about 1 intake per engine and i never tried that before. This is technicly an 1.2.2 install its on ps4. 

 

Thanks 

[Kerbalstar]

The Challenge is now closed.

Thank you to everyone who participated! @doggonemess will hand out the medals when they are ready, and @Lucast0909 will post the next challenge soon!

 

[vyznev]

16 hours ago, Kerbalstar said:

The Challenge is now closed.

Thank you to everyone who participated! @doggonemess will hand out the medals when they are ready, and @Lucast0909 will post the next challenge soon!

I know it's late, but I didn't manage to reach orbit with this thing when I first tried it yesterday.

It's a five part LF-only SSTO. I first tried making a four part one, but it turns out that none of the inline intakes carry quite enough fuel, so I had to add a separate fuel tank. Even then, there's a pretty narrow range where the vessel is light enough for a single Whiplash engine to take off and push it supersonic quickly enough, but still carries enough spare fuel for the nuke to finish the orbital insertion (which takes about 1000 to 1400 m/s of delta-v, depending on how much speed you manage to pick up before the jet flames out).

Flying it properly is a bit tricky, but I did finally manage to put it in orbit:

More screenshots here: https://imgur.com/a/mH7Mozh

Craft file here: https://pastebin.com/C6tsnQVP

Maybe this'll at least qualify for a honorable mention.  

[Kerbalstar]

4 minutes ago, vyznev said:

I know it's late, but I didn't manage to reach orbit with this thing when I first tried it yesterday.

It's a five part LF-only SSTO. I first tried making a four part one, but it turns out that none of the inline intakes carry quite enough fuel, so I had to add a separate fuel tank. Even then, there's a pretty narrow range where the vessel is light enough for a single Whiplash engine to take off and push it supersonic quickly enough, but still carries enough spare fuel for the nuke to finish the orbital insertion (which takes about 1000 to 1400 m/s of delta-v, depending on how much speed you manage to pick up before the jet flames out).

Flying it properly is a bit tricky, but I did finally manage to put it in orbit:

 

More screenshots here: https://imgur.com/a/mH7Mozh

Craft file here: https://pastebin.com/C6tsnQVP

Maybe this'll at least qualify for a honorable mention.  

4

Very wonderful! I'll have @doggonemess make you an honorable mention badge!

[sturmhauke]

I suppose the challenge was Single Stage To Orbit, not Single Stage Reentry From Orbit. Although with the EVA chutes you could probably bail out before crashing, at least.

[vyznev]

1 minute ago, sturmhauke said:

I suppose the challenge was Single Stage To Orbit, not Single Stage Reentry From Orbit. Although with the EVA chutes you could probably bail out before crashing, at least.

Exactly.

In fact, if I had some more spare fuel, I suspect that a SpaceX style vertical tail landing on the jet engine might be possible. I haven't actually tried it out in practice, though.

[Kerbolitto]

6 hours ago, vyznev said:

In fact, if I had some more spare fuel, I suspect that a SpaceX style vertical tail landing on the jet engine might be possible. I haven't actually tried it out in practice, though.

Depends if the airflow through the cooler has a front and back, or if it works both ways :p

[sturmhauke]

Precoolers are omnidirectional, which is ideal for that sort of thing. They don't pull as much air as a directional scoop though.

[AeroGav]

2 hours ago, sturmhauke said:

Precoolers are omnidirectional, which is ideal for that sort of thing. They don't pull as much air as a directional scoop though.

I'm not sure they are OMNI,  I have had problems when inadvertently mounting them backwards on a plane before (engine starts coughing once speed gets up).

Intake air is based on two values, a static one and a ram air rating.     The ram air rating goes up with increasing speed , though some of the low speed ones (radial supersonic intake , i'm looking at you!) start heading back down to zero again once you go past their peak.   The static rating is fixed, and the pre cooler has the highest static rating of any intake,  so it will work mounted backwards up to about 50m/s,  then the negative ram air number overcomes the static rating and causes insufficient air.

[sturmhauke]

Interesting, I don't think I've flown backwards with them.

[Dark Lion]

15 hours ago, vyznev said:

It's a five part LF-only SSTO.

WHAAAT?!  Noice! 

 

15 hours ago, vyznev said:

Maybe this'll at least qualify for a honorable mention.

I sure hope so! I kinda feel like that whole first quote deserves a medal unto itself! 
Simple, but genius. I never would've thought of that... 

[Lucast0909]

Universal Aerospace Challenge Flyer

Attention! Carrier Landing Challenge Issued!

Good evening (maybe) ladies and gentlemen. I am here to formally announce the following challenge: Land on the KSS Kerman (found here:  https://kerbalx.com/LucasT0909/USS-Kerman-Class-CV-Built-by-LucasT0909) with an aircraft of your choosing, provided it has at least one kerbal aboard.

Further Stipulations:

• The carrier must be located 75km from the KSC
• The carrier must be unmodified
• You are not required to get the carrier there under its own power (it doesn't move anyway)
• The aircraft used must survive the landing (no, stopping it with the superstructure doesn't count)
• Go nuts.

You'll need to have unbreakable joints turned on when launching the KSS Kerman, you'll also need to use some vessel moving mod to get it where it needs to be, I personally recommend Vesselmover. Anyone interested in those fighters can find them here: https://kerbalx.com/LucasT0909/UA-Myrmidon-F-57-Built-by-LucasT0909

Good luck!

Medal:

Edited January 3, 2019 by Lucast0909

[Kerbalstar]

Edit: Disregard, see my next post. Thank you.

 

Kerbalstar

Edited October 13, 2018 by Kerbalstar
Deleting misleading comment.

[AeroGav]

2 hours ago, Lucast0909 said:

•  
• You are not required to get the carrier there under its own power (it doesn't move anyway)

Might be easier if the carrier is moving, since that means less speed difference between the carrier and the airplane.

[FleshJeb]

@Lucast0909 I hope you don't mind, I've never built a ship in that style, and I really liked it.  So, I rebuilt your ship 60% lighter and a bit more seaworthy. It no longer needs unbreakable joints, thanks to autostruts. I built the "columns" with Grandparent, and set the endcaps to Heaviest. There's a bit of ore in the leftmost cargo bays to balance the mass of the superstructure.

She pulls to the right a bit, due to the uneven aero from the superstructure, but the SAS fixes that.

• Stage - Changes the control point to forward.
• AG1 - Engine toggle
• AG2 - Afterburners

https://www.dropbox.com/s/iypbj34yejub57o/Aircraft Carrier.craft?dl=0 (Stock KSP ver 1.4.5, approximately the same part count)

@AeroGav That should be fast enough.

Spoiler

 

Edited October 14, 2018 by FleshJeb
Oops, left the MechJeb module on. Fixed now.

[Kerbalstar]

3 hours ago, Kerbalstar said:

By the way, I added this rule.

Er... I’m an idiot. Just so you know, as of now, you are only allowed to use @Lucast0909‘s carrier. If @Lucast0909 says it’s okay you can use @FleshJeb‘s carrier. Please do not design your own carrier, it needs to be standardized. I realize that posting that right after the challenge might be misleading. When I get to my computer, I will change the wording to: unless a challenge says so only craft you build are allowed.

Edited October 13, 2018 by Kerbalstar

[hoioh]

Instead of using a vesselmover, can you please issue a savegame where the vessel is in place?

This would completely negate the ambiguity problem about craft use and will make the challenge a lot more accessible

Edited October 13, 2018 by hoioh

[vyznev]

9 hours ago, hoioh said:

Instead of using a vesselmover, can you please issue a savegame where the vessel is in place?

This would completely negate the ambiguity problem about craft use and will make the challenge a lot more accessible

Here's a save I made with @Lucast0909's original carrier placed just about exactly 75 km due east of the launch pad (by straight-line distance, so a little more as measured over Kerbin's non-flat surface).

I made it using KSP v1.4.5 with the Making History DLC enabled; let me know if there are any compatibility issues. I also had KER and Vessel Mover installed (the latter just for this challenge; that carrier indeed doesn't fly worth ****, not even with gravity hacked down to 1% of normal), but those shouldn't hopefully affect the save in any way.

Here's a screenshot of the carrier in place, with the target set to a Stayputnik sitting on the launch pad.

Have fun!