Fastest Juno-powered aircraft

[GDJ]

I may be mistaken but I think this is the 3rd or 4th plane here that uses the MK2 parts.

Just a hair over 683 m/s dead level flight. .

Edited July 1, 2018 by GDJ

[RealKerbal3x]

35 minutes ago, GDJ said:

I may be mistaken but I think this is the 3rd or 4th plane here that uses the MK2 parts.

Just a hair over 683 m/s dead level flight. .

Actually you're only the second Mk2 plane; @Klapaucius entered first using Mk2 parts and then posted a couple of non-eligible planes for funzies. But thanks for your entry!

Edit: Woot! 7 pages!

Edited July 1, 2018 by RealKerbal3x

[Lisias]

17 hours ago, RealKerbal3x said:

Hehe. You've posted that pic so many times I'm surprised it's not your profile picture by now

It's on my desktop's wallpaper.

15 hours ago, Andetch said:

I know how hard it can be squeezing a few m/s more from a craft! I need 18 m/s more too. Currently getting 2 m/s more. (So my best is actually 803 m/s)

Sometimes we need to throw through the room's window any previously knowledge from RL and realize this is KSP. I finally solved the problem in the most classic Kerbal way. I'm screenshoting and posting the aircraft, I'll edit this post with the data.  

NEW ENTRY

Well, suddenly I realized that I could not further increase my speed on the previous design without a overhaul. But after a lot of effort later, I just could not advance enough. Since we don't have a Wind Tunnel available on KSP, I had no choice but to fly, register, record and compare every modification trying to figure out what was compromising my 'score'.

Well… I finally reached the conclusion that Wings Are Overrated. I ditched the new design, took the old and added MOAR JUNOS and replaced the wings with the lightest winglet I could - you need something to act as a rotational pivot, or que winglets with control surfaces would lead the vessel into a chaotic Unexpected Uncontrolled Landing.  

So this is it. My Mk1 entry reached 737.24 m/s - and, yeah, that 0.24 m/s is relevant - I wasted 2/3 of a fuel tank to reach that (and hit the ground exactly after, as I was flying low and on the current viewing angle, I didn't saw the ground popping out from nowhere!  ).

Craft on kerbal-x.

p.s.: I don't have the slightest idea in how in hell I would land the thing… I' afraid the landing gears will not withhold the touch-down at the minimum speed this thing needs to keep on flight…

p.s.2: I'm building a new rig for KSP, and the control issues I was having with automatic pilots are solved. The problem was the my previous rig was not fast enough to the autopilots be able to fine tune the control surfaces on the pace needed.

p.s.3: Jebediah is insane.

Edited July 2, 2018 by Lisias
adding entry. Fixed kerbal-x link

[RealKerbal3x]

Woot! TOTM!

No seriously. Check the TOTM thread.

@Lisias I’ll update the leaderboard later as I just don’t want to deal with the trauma of the post editor on mobile right now

Edited July 2, 2018 by RealKerbal3x

[swjr-swis]

13 hours ago, Lisias said:

I just could not advance enough.

I can't load your plane in 1.3.1, and the pics you have posted don't show it well enough to rebuild, so I can offer only limited help, but I can see a number of things that would help improve that plane:

• You can cut a good amount of drag by minimizing the number of intakes. The single DSI I see on the tail section is plenty by itself to feed up to 25 Junos, which means you could remove the radial ones and replace (most of?) the small circular ones by small nosecones.
• You say wings are overrated and cut down on them, but having enough wing to keep the plane 'afloat' helps in maintaining a small angle of attack, and thus, minimizing body drag. I can't tell from the pics how many basic fins you use, but it it's just the visible ones, that is not enough for the mass of that plane. Body drag is very likely setting the speed limit of your plane at the moment.
• Switch the landing gear for the smallest retractable gear. Yes, they are marginally heavier, but once retracted they are a lot less draggy in flight, which quickly overrides any downside from the tiny extra mass. As an added bonus, they are much stronger for landing on.

[GDJ]

@RealKerbal3x

I did some aerodynamic tweaking and added 2 more Juno's.
701.4 m/s dead level flight.

Still not the fastest, but for a MK2 plane.....not too shabby.

Edited July 2, 2018 by GDJ

[The Minmus Derp]

1 hour ago, GDJ said:

I did some aerodynamic tweaking and added 2 more Juno's.
701.4 m/s dead level flight.

Still not the fastest, but for a MK2 plane.....not too shabby.

I’m pretty sure that that’s the fastest mk2 plane here!

[GDJ]

2 hours ago, The Minmus Derp said:

I’m pretty sure that that’s the fastest mk2 plane here!

I think you're right. I know I can add 2 more Juno's, but the aero is pretty much tweaked out and still have a plane that can easily take-off and land. I'm going to leave it since based on what I've observed on adding motors, I may gain about 5 m/s.

She's as fast as she's gonna get since MK2 parts are basically as aerodynamic as a brick.

But hey! Fastest MK2 plane on the board? I can live with that!

Edited July 2, 2018 by GDJ

[RealKerbal3x]

11 minutes ago, GDJ said:

She's as fast as she's gonna get since MK2 parts are basically as aerodynamic as a brick.

Which is weird as they look like they'd be slippery and aerodynamic

[GDJ]

10 minutes ago, RealKerbal3x said:

Which is weird as they look like they'd be slippery and aerodynamic

Yeah, they do look good.

[GDJ]

@RealKerbal3x

FINAL UPDATE ON THIS PLANE! 

Had a brainfart (or whatever you call it) and did some alterations.

732.2 m/s on a level flight. Trimmed the leading edges of the wings for near zero angle of attack on the fuselage.


This has to be the fastest flyable MK2 plane in this challenge.....this time.....for now.....

[RealKerbal3x]

1 minute ago, GDJ said:

@RealKerbal3x

FINAL UPDATE ON THIS PLANE! 

Had a brainfart (or whatever you call it) and did some alterations.

732.2 m/s on a level flight. Trimmed the leading edges of the wings for near zero angle of attack on the fuselage.


This has to be the fastest flyable MK2 plane in this challenge.....this time.....for now.....

Great job....just loading KSP so I can’t update the leaderboard right now. But later!

[GDJ]

10 minutes ago, RealKerbal3x said:

Great job....just loading KSP so I can’t update the leaderboard right now. But later!

No problem.

Too bad there isn't a "Pretty" category.  

[RealKerbal3x]

50 minutes ago, GDJ said:

No problem.

Too bad there isn't a "Pretty" category.  

Hehe, yeah.

And I put you on the 'board

[Lisias]

12 hours ago, swjr-swis said:

I can't load your plane in 1.3.1, and the pics you have posted don't show it well enough to rebuild,

Kerbal-X is nice because it lists the parts used on the aircraft. I think it should be standard procedure publishing the entry on Kerbal-X due that.

 

12 hours ago, swjr-swis said:

You can cut a good amount of drag by minimizing the number of intakes. The single DSI I see on the tail section is plenty by itself to feed up to 25 Junos, which means you could remove the radial ones and replace (most of?) the small circular ones by small nosecones.

Hummm… Nice catch. I was in the mistaken believing that I would get the best results flying on thinner atmosphere, but then I saw the good numbers happening the low as possible, and forgot to adjust. Good catch.

 

12 hours ago, swjr-swis said:

You say wings are overrated and cut down on them, but having enough wing to keep the plane 'afloat' helps in maintaining a small angle of attack, and thus, minimizing body drag. I can't tell from the pics how many basic fins you use, but it it's just the visible ones, that is not enough for the mass of that plane. Body drag is very likely setting the speed limit of your plane at the moment.

I'm using canards and elevators. Sounds crazy, they also provides lift and less drag than wings. With two sets of control surfaces on both tail and nose, you have an incredible amount of control about the craft atitude - and the vectors end up acting as lifting too!

I'll post a picture of the Force Vectors on my next entry.

 

12 hours ago, swjr-swis said:

Switch the landing gear for the smallest retractable gear. Yes, they are marginally heavier, but once retracted they are a lot less draggy in flight, which quickly overrides any downside from the tiny extra mass. As an added bonus, they are much stronger for landing on.

Again, I missed that. On my career, I don't have tech for retractable landing gears yet - and forgot to adapt when I move the vessel to the Sandbox. Thx!

Edited July 2, 2018 by Lisias

[Lisias]

On 7/2/2018 at 2:49 AM, RealKerbal3x said:

@Lisias I’ll update the leaderboard later as I just don’t want to deal with the trauma of the post editor on mobile right now

If you don't mind, delay it for some more time. @swjr-swis insights won me at least 10 m/s more!!! I'll update this post with the mk2 entry soon.

EDIT: 10 m/s? I said TEN m/s? HA!!!  

NEW ENTRY: L's X1 Stock Mark 2 ("Wings are still overrated").

With the invaluable advices from @swjr-swis, I was able to reach 760 m/s !!  

So, here is my new entry:

@swjr-swis, as I promised, here follows the screenshots with the Force Vectors:

Any lifting surface adds drags, and I don't need more lift - I think that even the Basic Fin I added is not really needed for lift (just to provide pivotal axis for the control surfaces to act), as the aircraft manages to take off without it, she just don't keep flying the way I want without the Fins!  

The Canards adds a considerable amount of drag themselves - I would probably gain something by scratching either the canards or the elevators and then strapping some lifting surfaces. But I didn't managed to stabilize the craft by doing that - at least with this airframe. I will probably scratch her and start the L''s X-2 branch in order to pursue this.

Edited July 4, 2018 by Lisias
new entry; better choose of words

[GDJ]

1 hour ago, Lisias said:

If you don't mind, delay it for some more time. @swjr-swis insights won me at least 10 m/s more!!! I'll update this post with the mk2 entry soon.

Interesting. 

[neistridlar]

21 hours ago, Lisias said:

Any lifting surface adds drags, and I don't need more lift

I bet you could get away with even less wing surface if you increase the angle of incidence. I have not done extensive research on this, but around 5 degrees seem to be quite good. The Idea is that as angle of attack on the lifting surfaces increase, the lift generated very quickly, but as long as the angle is relatively small drag increases very slowly. You want to find the angle where the wings have the highest Lift/Drag (since the lift required always equals the weight).

[Lisias]

30 minutes ago, neistridlar said:

I bet you could get away with even less wing surface if you increase the angle of incidence.

There's no way to get less wing surface, as I already using the smaller lifting surface available from the game!  And frankly, the craft don't need it anyway, as all the hard lifting work on this craft is being done by the Control Surfaces. It's probably an exploit of the KSP' Physics Engine, but… Well, it's working.  

Other than that, yes, your advice is valid. I do it on cargo planes where lift is more important than speed, and also on some other planes where the main fuselage inclination causes more drag than the inclined wings - so by raising the wing's angle of incidente, the main fuselage "drops" the nose on cruising, minimizing the fuselage's drag.

p.s.: The link on the quoted text is mine.

Edited July 3, 2018 by Lisias
yeah. typos.

[neistridlar]

27 minutes ago, Lisias said:

There's no way to get less wing surface

Control surfaces are also wing surfaces .

[Servo]

I gave this challenge a shot and wound up with this little guy. Drag is the limiting factor, not weight, so I went for the manned category (and Jeb seems to be enjoying it). Level(ish) flight, I topped out at 793.2m/s. A similar craft, in a dive topped out at 813 m/s.

Things I learned - 

* Part count is everything. Get it as low as possible. 

*Everything should be inline wherever possible. Avoid transitions between different sizes of tank, and if you do, use an adapter

*intakes are basically optional. At speed, you need one intake per 10+ engines

Using these insights (the intakes one was big), I redesigned and made an unmanned probe with 17 Junos that hit 815.7 in a slight dive.

[GDJ]

@RealKerbal3x

Had another idea at work today and gave it a try. Changed the rear of the plane, staggered the engines so none of them would have any interference with each other and tried to keep them as low to the fuselage as possible. Also changed out the other vertical stabilizers to wing strakes and canted them. It worked well.



743.4 m/s at level flight.

Edited July 4, 2018 by GDJ

[FunThomas]

760.1 m/s at sea lvl, i could squeeze a little bit more but for some reasons this plane keeps rolling to right

view from top 

Edited July 4, 2018 by FunThomas

[Lisias]

Interesting. Something exactly the inverse from what I'm pursuing!  

8 hours ago, FunThomas said:

760.1 m/s at sea lvl
 

Challenge accepted.  

 

8 hours ago, FunThomas said:

i could squeeze a little bit more but for some reasons this plane keeps rolling to right

Check the fuel balance, and you probably need better elevators/stabilizers. The one you are using produces less drag and it's lighter , but the AVR-08 (that's the name? I forgot) produces more control.

Edited July 4, 2018 by Lisias
whoops… typo

[RealKerbal3x]

Got a few more entrants. Thanks guys!  I’ll sort you all out later