Fastest Juno-powered aircraft

[swjr-swis]

45 minutes ago, Pds314 said:

Maybe there should be a lower maximum limit on the number of engines or require the craft to be.. you know.. a plane... that can take off and land...

OP's starting example sets the tone of what type of craft is expected to show up for this challenge.

Even so I think there's a good number of entries that are planes by any definition you wish to use - they can take off and land, take off horizontally by means of lift, have control surfaces and landing gear, and even piloted by kerbals. Including the top manned entry. There's mk1, mk2 and even mk3 cross-sections represented on the leaderboard.

As for a limit of engines: that would just put a different arbitrary limit on the upper bound, and we can argue about how many engines philosophically no longer constitutes a 'realistic aircraft'... 8, 10, 12, 14, more? (although people will argue that both the B52 and the Dornier Do X were clearly cheating... since they're clipping their engines together and all).

[DunnoAnyThing]

Hmm, still top record's 820m/s... maybe that's the upper barrier?

[Lisias]

18 minutes ago, DunnoAnyThing said:

Hmm, still top record's 820m/s... maybe that's the upper barrier?

Yep. The Junos start to choke when in the intake air reaches mach 1, until the point they get a flame-out.

[TeslaPenguin1]

Just a question: Are we allowed to use normal rocket engines, then decouple a Juno payload from them?

I have an idea for putting something into orbit, then deorbiting.

 

[swjr-swis]

1 hour ago, TeslaPenguin1 said:

Are we allowed to use normal rocket engines, then decouple a Juno payload from them?

Well, the rules state:

On 6/14/2018 at 8:45 PM, RealKerbal3x said:

2. Only Juno engines are allowed, e.g no rocket engines.

Which seems pretty clear by itself. But this exact question was asked before in this thread, and answered by @RealKerbal3x:

On 6/19/2018 at 5:03 PM, RealKerbal3x said:

However, the only engine allowed in this challenge is the Juno, so your carrier would have to be powered by those too, sorry

[Kebab Kerman]

I wonder what I can do on this... HmMmmMMmMMmMmMmMmmMmMmmMmMMmmmmm...............

 

hehehe

At least, when my harddrive comes.

[Kernel Kraken]

I'm recalling a project from the 60's to take a battleship cannon, put a rocket in it, and shoot it into orbit. Brainstorm copyrighted for now because I want my 5 minutes of leaderboard time. Coming Soon!

[RealKerbal3x]

13 hours ago, Kernel Kraken said:

I'm recalling a project from the 60's to take a battleship cannon, put a rocket in it, and shoot it into orbit. Brainstorm copyrighted for now because I want my 5 minutes of leaderboard time. Coming Soon!

Sounds great. Make sure the only engine you use is the Juno though, as per the rules.

[Thorn_Ike]

I wasn't able to beat 820 m/s, but I think I got close enough.

817.3 m/s.

That screenshot had to be taken in a video replay, since this was coming in from a dive of 25,000m.

The unaltered video: https://mega.nz/#!o9glVASJ!ReApSwK3YjjpguTifuLuFMCUgAAu15DJ-gBM1fcQNno

[Pds314]

The limits of sustained speed are probably the limits of the Juno thrust curve. Roughly Mach 2.4. The only way I could see a craft exceeding this limit for very long at all is if you use the alternator output of a Juno to power a reaction wheel, since we know for sure these can get over 1 km/s.

The other possibility is of course motion that isn't linear. Nothing in particular prevents you from having the blade tips of a Juno- powered super-helicopter reach hypersonic speeds, as long as the engines aren't actually on the bladetip.

 

It might also be possible to exploit the push the Junos give from thrust pressure to reach very high speeds as long as the Junos themselves are sometimes at speeds low enough to produce thrust, or are, sealed in airflow the game considers static. I.E. a juno provides no thrust at the edge of a wheel spinning a kilometer per second, but can easily push on things that ought to be faster escsping than its own exhaust because of the magic of raycasting

Edited January 15, 2019 by Pds314

[Lapis]

is diving allowed, I know this thread is a little old, but i want to know if it is just level flight.

 

[RealKerbal3x]

11 hours ago, lapis said:

is diving allowed, I know this thread is a little old, but i want to know if it is just level flight.

 

Sure, but remember that you can only use Juno engines to get to altitude.

Also, I'm going to try and bring this challenge back, if anyone wants to give it a go

[Flying dutchman]

I just did a crewed mach 1.1 on a single juno.

[Lapis]

I decided to try a seperating wing design, i don't know if this has been done before here. there are two pylons clipped into the body holding the wings on.  here is the design:

here it is with it's wings decoupled(I forgot to take an end of mission screenshot)  but I got this:

so 757.3m/s

 

Edited May 4, 2019 by lapis

[RedSun Rocketry]

has anyone tried doing this challenge on laythe instead?

[Lapis]

31 minutes ago, RedSun Rocketry said:

has anyone tried doing this challenge on laythe instead? 

no, and there is nothing in the rules against it, as long as you take off from the ground i think it should work. but i am not the OP, so it is whatever @RealKerbal3x decides.

Edited May 4, 2019 by lapis

[RedSun Rocketry]

if I remember correctly laythe does have a slightly thicker atmosphere than kerbin so if you send it there you would be able to go farther than on kerbin from a fixed point

[Lapis]

Eventually I think it is more about the drag than anything else.

[RealKerbal3x]

@RedSun Rocketry @lapis I think I’ll add an amendment to the rules that you’re only allowed to make your attempt on Kerbin. I don’t want anyone to have an unfair advantage because they flew on Laythe with its thicker atmosphere.

[Hotel26]

On 10/20/2018 at 3:29 AM, Kernel Kraken said:

I'm recalling a project from the 60's

https://en.wikipedia.org/wiki/Project_HARP

[Lapis]

@RealKerbal3x that post I made is a submission.

[RealKerbal3x]

15 minutes ago, lapis said:

@RealKerbal3x that post I made is a submission.

Oops, I missed it. I'll add you to the leaderboard

[swjr-swis]

12 hours ago, RedSun Rocketry said:

if I remember correctly laythe does have a slightly thicker atmosphere than kerbin

Laythe has a 0.6 atm sea level pressure - it's thinner than Kerbin's.

 

12 hours ago, lapis said:

Eventually I think it is more about the drag than anything else.

The entries in this thread show that on a sufficiently optimized craft drag is no longer a factor, and the constraint becomes the Juno power envelope (Mach 2.31 @ ASL apparently being the best possible result before flame out). So on Laythe, like on Kerbin, on a drag-optimized craft the highest speeds will be achieved just above sea level (dictated by its atmCurve).

Mach number is directly derived from the speed of sound, which mostly follows the same curve as air temperature. Air temperature within the Juno's altitude range is highest at ASL, and is lower than Kerbin's. Given all this, it's to be expected that the Juno will flame out at a lower air speed on Laythe than on Kerbin.

A quick test dropping my JunoSpeeder-3c on Laythe only yielded a 772 m/s top speed at about 50 m over the ocean surface. The real top speed is probably a bit higher since I spent no effort optimizing (wing AoI and pitch trim made a difference on Kerbin), but flame out was happening around Mach 2.29 already, so it seemed a waste of time to dedicate much effort to this.

Feel free to try though, and keep us posted on the results.

 

[RedSun Rocketry]

the challenge can only be completed on kerbin anyway

[Lapis]

12 minutes ago, RedSun Rocketry said:

the challenge can only be completed on kerbin anyway 

that was just recently added to the rules, but if you mean if it is possible, jet engines work on laythe.

Edited May 5, 2019 by lapis