What is the least useful non-structural part?

[tetryds]

IMO the RoveMax Model XL3 is just a piece of junk.

[makinyashikino]

Too many parts on the command, aerodynamic, and utility tabs are tempting (eg: the Probodyne QBE, OKTO, Engine nacelle, covered solar panels...)

There is literally no purpose to use the covered solar panels, they are just dead weight.

[FITorion]

The solar panels in boxes.

Why would I saddle myself with extra weight for zero benefit?

[ddavis425]

I have never used this winglet and I literally cannot think of any purpose it would have.

[makinyashikino]

I have never used this winglet and I literally cannot think of any purpose it would have.

It's just a rigid winglet, incase you want something to point straight up. It's more of a blast to the past really.

[Spatzimaus]

The basic jet is far more efficient on liftoff: it has 150 kN thrust rather than 112.5 kN, 2000 Isp rather than 400 (taking into account half thrust), and is slightly lighter to boot.

A few things:

> ISP doesn't drop just because you're effectively at half throttle. It's a measure of fuel efficiency, and it seems that the turbojet will still be tooling along at an 800+ ISP even at sea level. (Just right-click on the engine to see what I mean.) It's still outclassed by the basic jet for efficiency at sea level, but that brings us to the next issue:

> According to the right-click tooltips, the breakeven point for ISP is about 2000m; above that line, the turbojet has higher efficiency. Even if you think the tooltips are wrong, and not reflecting the thrust scaling correctly, you're still talking about altitudes that are rarely used. After all, even if you want to stay in the atmosphere you're usually better off going above the thick layers of the atmosphere before cruising.

> The breakeven point for thrust is a couple HUNDRED meters. Seriously, try it; make a plane that has both jets, and see how much thrust each is generating at a given altitude. At about 250m, a turbojet thrusts 129kN (out of its maximum 225), while a basic jet only gets 126 (out of its max 150). Sure, it'll be burning through fuel almost three times as quickly, but the thrust advantage of a basic jet doesn't even hold for atmospheric cruising, let alone suborbital trips.

> The turbojet also has a lower stall threshold (10kN versus 20kN). This is handy when you want to do a controlled landing in rough terrain, since even a small amount of thrust is enough to keep the thrust vectoring in place.

The point wasn't that the basic jet is a horrible piece of equipment. It's that you'd be hard-pressed to find a design that would gain more benefit from using one versus using a turbojet, because its stated advantages are too slight and too narrow in scope. I'm hoping that, given the addition of the SABER in 0.23, they'll redo the stats for the basic jet to be a bit better.

[Aragosnat]

I have never used this winglet and I literally cannot think of any purpose it would have.

Back in the day. They where used as landing gears for the Mün. I have used those as a way to keep the small SRB from exploding from over heating. But, for me the poodle is the least used. As there are better engines for pushing then that. At least for myself.

[Madrias]

My choice on the least useful part... Toroidal fuel tanks. Took a while, but I picked a part. I find I never use them, due to their poor fuel capacity, and I find better choices for tanks.

[makinyashikino]

My choice on the least useful part... Toroidal fuel tanks. Took a while, but I picked a part. I find I never use them, due to their poor fuel capacity, and I find better choices for tanks.

They're decent if you use them with the Ant engine, but that's only for space Probes.

[Wheffle]

Why are people saying the linear RCS port is useless? On a tall rocket where you are unable to place a 4-way directly on the nose or on the tail, the linear RCS ports are the only way to get good torque.

[Madrias]

They're decent if you use them with the Ant engine, but that's only for space Probes.

I use the small Oscar-B tank. Most of my probes are 1/2 meter type.

[Nimaci]

The cluster only really works for first stages though, as you can't nicely stack them without having to put more parts on in the form of struts as the cluster is more bulky (which also makes the cluster less useful for radially attached booster stages).

Increased first stage performance is kind of the entire point of using the 2.5m 30/45 cluster, especially for a monolithic launcher. Also the 2.5m 6xT30 + 1xT45 cluster parallel staging requires the same decoupler/strut configuration as Mainsail or Skipper 2.5m parallel staging.

[RadHazard]

I love the linear RCS port. That's how I can RCS-balance things like this:

I'd say one of the least-useful parts is the shielded docking port. It provides no advantage (aside from aesthetics) over the regular docking port and has extra weight.

Edited December 17, 2013 by RadHazard

[makinyashikino]

I use the small Oscar-B tank. Most of my probes are 1/2 meter type.

I like the ROUND-8's better because they hold almost twice the fuel, at the cost of some... ascetics.

[FlamedSteak]

I'd say one of the least-useful parts is the shielded docking port. It provides no advantage (aside from aesthetics) over the regular docking port and has extra weight.

Isn't that improving stability like nose cones now? That being said, I haven't noticed nose cones making much of a difference if any in 0.23.

Also mad props on the space bus.

[I_Killed_Jeb]

I love the linear RCS port. That's how I can RCS-balance things like this:

IMG

I'd say one of the least-useful parts is the shielded docking port. It provides no advantage (aside from aesthetics) over the regular docking port and has extra weight.

this is KSP, aesthetics is at least 100% of the point here!

[ArmchairGravy]

This here was going to be my runner-up, but I just assumed that somebody, somewhere had come up with an actual use for it.

I use it with the small kethane converter so I have a fuel tank directly attached.

My vote is the avionics nosecone.

[UmbralRaptor]

Isn't that improving stability like nose cones now? That being said, I haven't noticed nose cones making much of a difference if any in 0.23.

All docking ports have 0.25 drag (compared with the 0.2 of most stock parts and 0.1 of current nosecones). They actually reduce stability slightly if placed at the front of a craft.

My vote is the avionics nosecone.

In 0.21, I'd generally agree. But they provided an alternative ASAS tuning in older versions, and are useful in campaign mode now...

[khyron42]

So far, I've never used the Stratus-V Cylindrified Monopropellant tank, the PB-X50R Xenon Container, or the Inline Advanced Stabilizer. Almost everything else has gotten used for aesthetics if no other reason.

Linear ports - if you want to keep two sides of your rocket clear for other radial attachments, you can set symmetry to 2-way and put a linear and a quad RCS at the top and bottom of the rocket, and have full three-axis control from just those with only two of each at each end instead of 4 quads at each end. I often do that on landers where I want the ability to dock the craft, but also want space clear all along one side for a ladder and the other side for landing views.

[numerobis]

A few things:

And my reply. tl;dr: the basic jet has more thrust than the turbojet at speeds below 150 m/s and better TWR at speeds below 240 m/s. It has better effective Isp at speeds below 200 m/s at any altitude, particularly at low altitude (below 6km), beats the turbojet at speeds up to 250 m/s at the edge of space, and always beats the turbojet at sea level. In other words, the basic jet is good for hovering or otherwise spending a long time sight-seeing low and slow. The turbojet is good for getting places fast.

Note that IRL jet airliners fly at about 250 m/s at an altitude equivalent to Kerbin's 7-10km level. The basic jet allows you to emulate that (except KSP jets have very high thrust for their mass).

Hence my contention the basic jet is not among the least useful parts: there are good niches for it.

> ISP doesn't drop just because you're effectively at half throttle. It's a measure of fuel efficiency, and it seems that the turbojet will still be tooling along at an 800+ ISP even at sea level. (Just right-click on the engine to see what I mean.) It's still outclassed by the basic jet for efficiency at sea level, but that brings us to the next issue:

Yes and no. The Isp that's listed goes into the equation for mass flow, and determines how much fuel and air you'll be burning based on the listed Isp, the max thrust, and the achieved throttle; that's listed in the fuel consumption number. The thrust that's listed is throttle * max thrust * the velocity curve, and your plane accelerates based on that. So now you have an actual mass flow, and an actual thrust, so you can calculate the actual Isp. Basically, you just multiply the listed Isp by the velocity curve. So yes, the number says 800s or so at sea level for a stationary turbojet -- but if you look at fuel consumption versus thrust, the answer is 400s.

I drew the following graph some time back to plot in red the effective Isp of the turbojet versus in blue that of the basic jet; spots that are bright red are good for turbojets, blue are good for basic jets. X axis is the speed in m/s, Y axis the altitude in m at Kerbin. The bright horizontal line is 6km and the bright vertical line is 1km/s.

> The breakeven point for thrust is a couple HUNDRED meters. Seriously, try it; make a plane that has both jets, and see how much thrust each is generating at a given altitude. At about 250m, a turbojet thrusts 129kN (out of its maximum 225), while a basic jet only gets 126 (out of its max 150). Sure, it'll be burning through fuel almost three times as quickly, but the thrust advantage of a basic jet doesn't even hold for atmospheric cruising, let alone suborbital trips.

Thrust doesn't depend on altitude; it depends only on speed (surface velocity, to be precise). If you're hovering at the edge of space, the basic jet gets full thrust whereas the turbojet gets half thrust. If you're getting 129 kN from your jets that means you're flying at about 150 m/s. That's the break-even for thrust; the break-even for thrust:weight ratio of the engine itself is a bit higher, at about 240 m/s, because the basic jet is lighter.

> The turbojet also has a lower stall threshold (10kN versus 20kN). This is handy when you want to do a controlled landing in rough terrain, since even a small amount of thrust is enough to keep the thrust vectoring in place.

Stall threshold? You can run a jet at whatever throttle you want, it won't flame out just from being at low throttle. I have experienced that if I let throttle go to zero, I need to bump throttle up well above zero before the jet starts using fuel (and maybe generating thrust, but usually when I see this I've reached orbit and just want to dump excess jet fuel before an interplanetary cruise).

Edited December 17, 2013 by numerobis

[SpacedCowboy]

Yes, I agree! The Mark 55, despite that it's a gass sucker, placed in your staging just right, it can be a mission saver.

[SpacedCowboy]

Yes, I agree! The Mark 55, despite that it's a gass sucker, placed in your staging just right, it can be a mission saver. Least usefull constructural part? , that's a hard one ! I know it's constructural but the small hard point, whatever it's called, I never seem to use.

[CalculusWarrior]

I find (apart from that godawful white radial engine) that my least-used part is the Advanced Canard. It has exactly the same statistics as the standard canard, but I've always found that it looks very out of place on any of my ships, and tend to avoid it.

Also the Inline Advanced Stabilizer, ever since 0.21 and the reaction wheels change, I've stopped using it due to its higher weight with respect to the standard reaction wheels.

[Stargate525]

Yes, I agree! The Mark 55, despite that it's a gass sucker, placed in your staging just right, it can be a mission saver. Least usefull constructural part? , that's a hard one ! I know it's constructural but the small hard point, whatever it's called, I never seem to use.

Cubic octagonal strut?

It's my bread and butter. The only real way to turn a hardpoint-mounted item into a radial-mounted one (duna dragchutes, I'm looking at YOU).

[Grumman]

LV-1 Liquid Fuel Engine this useless piece of ...tech... has never been used by my space agency. The much hated LV-1 Liguid fuel engine. 1.5 thrust almost no thrust and a pain in the ass to mount non radial.

I have found one good use for these, and that's for my escape module module. 1.5 thrust is sufficient when all you need to do is put a Kerbal in a decaying orbit.