Uses of basic jet engine in early career?

[simsatellite]

The basic jet engine seems to lose a lot of thrust if I go too fast or too high (I find it hard to maintain speed around 10km or so.) I looked around the wiki and in the cfg file, and it seems that it's designed to be that way (the atmCurve goes down very quickly.) It's low on the tech tree, so my question is, what exactly can I use the basic jet engine for in early career?

Initially, I thought it was designed for all of those Kerbin survey contracts, but they all want an altitude reading at like 18km+ or so, which seems impossible to reach with a basic plane (okay, I know it's not impossible according to some challenge posts, but it's very hard for new players like myself.) For parts testing, it's just so much easier to put them on liquid fuel rockets.

The only use I've found for it so far is strapping one to my makeshift rover (made it with the cheap landing wheels since real rover wheels are higher up on the tech tree) and drive around KSC for science. Saves me a lot of fuel compared to an equivalent rocket-powered rover.

I think it does provide a nice educational value about how (hard it is) to design planes, but it just doesn't seem to help with any in-game contracts or goals. So, what am I missing?

Edited May 19, 2015 by simsatellite

[Invader Jim]

I used it for short range (same continent as base) surveys in flight that specify "below" a certain altitude. You are correct in that it can't get high enough for the "above" surveys. I also used it to fly to and then land on ground survey locations.

[DancesWithSquirrels]

I use the basic jet(s) on my planes for early-career surveys, adding additional tanks and two Terrier 909's to boost for high altitude surveys once in the right area. The jet rover is simple to use for very early science too, but I generally don't bother with that.

[EtherDragon]

You can use the basic jet engine to go around to lots of biomes and do Crew Reports while Flying Over them. Bring an Antenna to transmit your data.

If you feel really adventurous you can try to land on various biomes and do Crew Reports while landed, as well as EVA Reports. Again bring an antenna to transmit. Your Jet Engine will provide plenty of power.

[simsatellite]

I didn't realize that some survey contracts specify "below", I always assumed it's "above"... That explains why I keep getting 'trivial' contracts that don't appear trivial to me... Guess I should read contracts more carefully.

Strapping Terriers to boost a plane up high sounds intriguing. I tried that with Thuds once and it flipped out of control, but then again, I'm not good at designing planes nor flying them, and I tried that before knowing about action groups... I'll have to give it another shot.

[DancesWithSquirrels]

Mk1 cockpit, two Mk1 liquid fuel fuselages with science mounted (Goo and thermometer on top, I've put the Materials bay in the middle for balance), basic jet engine and basic wheels, radial air intake, a couple of control surfaces in a 'V' on top.

On the sides, two FL-T400's with nose cones and 909's, then whatever wings and ailerons you've got unlocked. I keep the LF in the -400's locked until I'm about to boost so the jet doesn't suck it down.

Full power at 8-10K, crank the nose up and stage the 909's when you start to lose thrust. Get some speed on, shut the engines down and coast through the survey altitude. I can easily get to 20K that way. Shut down the 909's, lock the LF in the side tanks, and restart the jet once you've coasted back to 6-8K. Reset staging, head to the next survey area, repeat. Action groups are not required.

Edit: I wonder - if I put two radial intakes low on the Mk1, if I could use them to clamber back up to the cockpit when I haven't unlocked the ladders yet. I'll have to give that a try...

Edited May 19, 2015 by DancesWithSquirrels

[Ferrous]

On the topic of out of control jet plane with LFEs... you probably know this already but you will want to align thrust vectors on all three possible occasions, a) when only the jets are on, when only the LFEs are on, and c) when all of them are on. you can check all those by setting thrust limit at 0 with tweakables. (you can have some leeway with all three cases, the more gimbalable the engines are the more leeway you've got)

You can easily shut all of the LFEs down by forbidding oxidizer usage, it's easier to do most of the time, if you don't have group actions yet.

You will also need low atmo torque for your SAS, cause when you are high up the wings are useless, plop some reaction wheels and RCSs on will help a lot. flexible LFEs will also help, making thud one of the best ones for the job (which is why it's kinda weird you couldn't make it work with thud)

Finally you need to be aware that burning fuel will change your center of mass, which could bungle everything up, set your fuel storage to zero with tweakables and check if that would put your center of lift ahead of your center of mass, and make sure that it doesn't.

Back to your,.. already answered... question, the most powerful use of the basic jet engine is that it allows you to do surface surveys, which is really handy because those tend to come in couples, giving your jet planes a really high ROI, esp. on science points.

If the target is close you can just fly there, if it's more than a quarter away around Kerbin ... well, you either need to be real patient, or you can put a jet plane on a rocket. The important thing is you will be able to precision land once you are back in the atmosphere.

P.S. I do all of my "in flight" contracts with orbital dropped drones, those targets have a very huge margin so it's rather easy to get the drones into range, but the surface contracts are rather specific with your location, again, making the basic jet useful.

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It's a lot easier to climb via control surfaces, you could have 2 pairs aft for pitch control that doubles as a ladder

You can also make your craft "sit down" with the retractable landing gears if you researched 'landing' before 'space exploration'

Edited May 19, 2015 by Ferrous
typo

[DancesWithSquirrels]

"...2 pairs aft..." - I go for the V-tail to keep them out of the 909 exhaust. And I like the side-mounted 909's because the thrust line is always through the aircraft center, without vertical angle issues like the NF-104A:

[ajburges]

I alter my capsule recovery to hit high altitude survey points in the shock layer. Losing a few percent recovery is worth 3 science early game. Basic jet craft is used for lower altitude and the 300 or so science you can get from the KSC continent with thermometer, goo, EVA, science Jr, and capsule. Use a octo probe core so a scientist "flys" the jet.

I think Kerbin surveys should be rebalanced to 12-13 Km max altitude so that early aerobic craft can complete them with proper design and handling. I only do early surveys on the KSC continent and only if I can run 2+ simultaneously.

[Prepper-Jack]

Besides what's already been mentioned... they can be used to get a small to mid-size rocket to around 10km @ 300m/s at the trajectory of your choosing, for very little cost in fuel. The main booster can even suck the remaining fuel before jettisoning, provided you throw some fuel lines between them. It's a costly launch option, but an option nonetheless.

[Ferrous]

"...2 pairs aft..." - I go for the V-tail to keep them out of the 909 exhaust. And I like the side-mounted 909's because the thrust line is always through the aircraft center, without vertical angle issues like the NF-104A

I see, well maybe if you switch on your kerbal RCS and then jump with a boost you can reach your other wings?

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Besides what's already been mentioned... they can be used to get a small to mid-size rocket to around 10km @ 300m/s at the trajectory of your choosing, for very little cost in fuel. The main booster can even suck the remaining fuel before jettisoning, provided you throw some fuel lines between them. It's a costly launch option, but an option nonetheless.

That's a brilliant trick, if you play with the stage recovery mod you will probably save a bit of space bucks with this option XD

Edited May 19, 2015 by Ferrous
broken quote

[UnusualAttitude]

You can build a low-tech basic jet SSTO spaceplane. It will probably have a very modest payload fraction, but you get a 100% recoverable launcher for satellite contracts or science probes.

[Torquimedes]

Try these for early survey missions.

[steve_v]

You can also get a decent amount of science with a low-tech VTOL around KSC - the roof of each building appears to have it's own biome Yeah, I've been playing for a *while* and I just figured that one out.

[mrklaw]

How low tech can you build a VTOL?

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Try these for early survey missions.

Really like the one with the jet and rocket. Never tried downloading a craft file but going to try that one.

[steve_v]

I forget exactly, as my career save is now past that point, but this is fairly low-tech. Probably more so than whatever I actually used to get up there, but it's similar.

The spool time on the basic jet makes it *almost* impossible to fly, so you need to toggle the intakes for thrust control.

Adding some RCS or a small LFO engine would help enormously, but I like a challenge:

Don't ask how long that took, or how many kerbals perished in the attempt

Edited May 23, 2015 by steve_v

[Torquemadus]

For the early game survey missions, the waypoints that need to be done above a given altitude can actually be done from orbit. If you have the patience, you can put a spacecraft in either a polar or highly inclined orbit to overfly any nodes your jet planes can't get to.

[moondogccr]

... this can only get you so far. Used to do this until the survey targets started popping on the other side of the world at altitudes above 19,200.

Mitigated some of it by using stages to drop empty tanks along the way, but even then impossible to cover 2+ targets above 19,200 on a single trip.

[Torquimedes]

As Steve said, a jet VTOL is very difficult to land without intake and/or rocket toggling, but early in your career you don't have action groups for those controls. You can use his craft to get over the target and hover as best you can, then throttle down a bit and use the chute to cushion the landing because you won't have time to spool back up.

Off the topic of jets, it's possible to build a Tier 2 KSC hopper VTOL, steered only by a pod's torque. Use a pilot for SAS and very gently nudge it toward the building you want. Don't tip more than a few degrees off vertical. Tiny throttle adjustments to maintain vertical speed while the mass of fuel is being shed. If you run out of fuel while over a building, pop the chute and you may fall on target anyway. It might take some practice to learn how to get from the launchpad or runway to the target building with minimal fuel.

Edited May 23, 2015 by Torquimedes

[GoSlash27]

I use a simple basic jet to collect science from biomes all over Kerbin early-on. temperature, goo, science jr, crew reports, etc.

The science builds up in a hurry.

Best,

-Slashy

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You can also get a decent amount of science with a low-tech VTOL around KSC - the roof of each building appears to have it's own biome Yeah, I've been playing for a *while* and I just figured that one out.

Steve V,

Isn't the rooftop the same biome as the grounds next to the building?

I built a simple jet cart to drive to each building and collect science.

Best,

-Slashy

[Torquimedes]

Isn't the rooftop the same biome as the grounds next to the building?

I built a simple jet cart to drive to each building and collect science.

Best,

-Slashy

Can you get close enough to trigger the building biome from the ground? In that screenshot it says "VAB main building" while on the ground it says "VAB".

[GoSlash27]

Can you get close enough to trigger the building biome from the ground? In that screenshot it says "VAB main building" while on the ground it says "VAB".

Interesting!

So possibly the rooftops may be different biomes? That's a lot of science I've just got sitting around if so...

Best,

-Slashy

[Kerba Fett]

Steve's craft is a great design. I used to use those all the time. The easy way to land used to be to just pop the chute then repack it while you're on the ground, but now you need to use an engineer to repack chutes, so the flying is more difficult. Mods also help. Dazio's vertical velocity controller has some trouble with the spool up lag, but I was using it to tail land a full size jet, so maybe with the thrust limiter on the engine turned down it would manage better.

Another option would be to find the throttle setting needed to hover and use RCS for rapid thrust changes since that's independant of throttle setting.

Using jets as a booster to get rockets up is also a great use for them. They don't go as high any more, but they still get a lot higher than an SRB will last you.

When using them as a booster it's important to let them get to full power before releasing the launch clamps. Right click on an engine and wait till it gets to at least 90 to 95% of max thrust. You've got a limited amount of altitude for them to work so you might as well get all the push you can from the ground.

[Kerba Fett]

I played with a variation of Steve's craft. I used Kerbal Engineer to tweak the TWR to 2.0. For this particular craft that's 79% on the engine thrust limiter for those of you not running mods. I removed the oxidizer from the fuel tank but all the other tanks are full.

With a 2.0 TWR you get hover thrust with 50% throttle. To take off you can use 50% throttle and just use the H key to fire the downward facing RCS jets or just throttle up to 55 to 60% then throttle back to 50 once you're in the air.

To land start with 40 to 45% throttle then go back to 50% once you start to descend to maintain your descent rate. To slow your descent use short bursts of RCS and use X to cut your throttle when you touch down to keep from bouncing back up in the air.

You could also use upward facing RCS to help manage your vertical speed but you'll use your monoprop quicker. Also keep in mind that using precision mode reduces the thrust of the RCS jets.

I used that landing gear since it's what I had unlocked in career, but it also has the advantage that you can spin on your axis while landed.

By mounting a ladder right under the hatch, it defaults to an angle that gets over the RCS thruster and lets the pilot get in and out for surface samples.

It's a good short range craft that's fun to fly.

[Scoundrel]

Before I designed better exploration crafts I used this thing:

26 parts (including the antenna) before science - which was 2 Sci Jrs and 2 Goo at first. I used three engines for better throttle response, which at first I set to 50% thrust, but I set it back to 100% thrust because I found myself needing to stop my descents faster.

I had 4 parachutes on it, with three chutes on stage 1 and one chute on stage 0. The idea was to use the chutes on stage 1 to land wherever I needed to EVA/Report, and the chute on stage 0 to land back at KSP.

Obviously I replaced it with this guy once I figured out that a well designed roverplane was far more useful (and safe!) than a VTOL.