Basic Jet Escape?

[medbor]

I have an interesting challenge for you guys!

Primary goal: Maximum Karbin Apoapsis.

Secondary: Maximal Sun Apoapsis.

Bonus: Encounter with another planet.

Super-Bonus: Visiting another planet and getting back.

This might not look so hard, but the limiting factor of this challenge is the propulsion system. Only the Basic Jet engine is allowed in Class 1. Class 2 allows all AIRBREATHING STOCK engines. Class 3 is free MODS but still AIRBREATHING.

Infinite fuel is a separate sub-category B for above classes.

Any takers?

[vat21s]

http://forum.kerbalspaceprogram.com/threads/24898-Challenge-Submission-Guide

[Capt. Hunt]

Have you even tried this yourself? I'll save you the trouble, it's completely and utterly impossible!

[Redshift OTF]

Getting an apoapsis over Kerbin in Basic Jet engines is not impossible. The others though, erm, yeah. Would be tricky. Getting a Kerbin escape with any kind of jets would be hard I think.

[Othuyeg]

Modded entry would not be too hard, I presume. You need to strap a thermal turbojet onto an antimatter reactor in interstellar mod and you might have a shot at it.

[Kulebron]

I think it's marginally probable, if you keep vertical speed under control at the altitude about 30Km, to achieve an escape velocity of 3400m/s and even higher. But hitting laythe is too hard, and requires corrections in space, so not 0 probability, but really low.

This is the reason why Apollo missions did not do direct ascent/descent: orbiting Earth and Moon allowed to correct the accumulated errors. In case of this challenge, if you have exclusively jet engines, it's impossible.

Edited October 11, 2014 by Kulebron

[Michaelo90]

I think it's marginally probable, if you keep vertical speed under control at the altitude about 30Km, to achieve an escape velocity of 3400m/s and even higher. But hitting laythe is too hard, and requires corrections in space, so not 0 probability, but really low.

This is the reason why Apollo missions did not do direct ascent/descent: orbiting Earth and Moon allowed to correct the accumulated errors. In case of this challenge, if you have exclusively jet engines, it's impossible.

Aiming isn't the problem, the problem is that the basic jet is limited at 1000 m/s and the turbojet is limited at 2400 m/s. It MIGHT be possible to make it to laythe with only turbojets if you really abuse intake spamming, but with basic jets, you can't even orbit kerbin.

[Javster]

Can't you spam intakes and use them to store intake air?

[Laie]

Getting an apoapsis over Kerbin in Basic Jet engines is not impossible.

Really?

One can't possibly go faster than 1000m/s on basic jets, as that's the point when their thrust reaches zero. Actually, thrust becomes abysmal long before that. That forces you to fly a relatively steep suborbital trajectory, where you have a lot of either gravity drag or actual aerodynamic drag. The true top speed, where thrust equals drag, is probably no more than 800m/s even for the tiniest vessel. That would require considerable use of massless parts and intake spam. I don't say it's impossible to leave the atmosphere on basic jets, but I expect that it would take a lot of fine-tuning of your parts and flight profile.

Getting a Kerbin escape with any kind of jets would be hard I think.

Getting to (say) 90x68km isn't very difficult (on turbojets, that is). After that, I don't know. I've heard about storing intake air, but never tried that myself. Even the tiniest push would suffice, though.

Edit to add: turbojets reach zero thrust at 2400m/s, IIRC. Not enough to leave Kerbin SOI, at any rate, and not enough to get a gravity assist from the Mun either.

Edited October 12, 2014 by Laie

[Endersmens]

use FAR for modded. It will be easy. I once had a jet go to the mun and back on turbojets. I angled the plane down, and sped around the planet at 3,000 m/s till it was a munar encounter and then let go and made it back without using anything but turbo jets. I could've gone faster too.

[Redshift OTF]

Edit to add: turbojets reach zero thrust at 2400m/s, IIRC. Not enough to leave Kerbin SOI, at any rate, and not enough to get a gravity assist from the Mun either.

This I didn't know. I knew there was some kind of hard limit programmed into the game for Turbo Jets but I didn't realise they did this by reducing the thrust at near orbital speeds.