Are fairings useless?

[Jouni]

Well wait a moment, I will start up KSP right now and take 2 Screenshots for example and load the craft file up so everyone can try it out.

The problem is that you're flying way too fast. Remove two of the LFBs and add a similar amount of fuel elsewhere, and the rocket will behave much better. A good launch TWR is 1.2-1.4 (or perhaps even lower, now that air pressure changes engine thrust), and it's rarely a good idea to let the TWR grow above 3 during the launch.

[Murph]

It is your incompetence, but not as a pilot. There are struts going through your fairing wall.

You can do it with struts and without the fairing, or you can do it with the fairing and without struts. But don't do it with both, at least not with struts going through the fairing wall. Or maybe it's something else, I don't know, but it looks like it's the struts causing you trouble.

Do Squad fairings auto-strut the payload inside them? I don't believe they do, or at least have not yet seen mention of that, so the struts at the narrow point of the payload are likely critical (but probably don't need as many with the wind load taken off the payload). It's a fair comment that the struts actually penetrating the fairing could be an issue, although I don't know for certain that it does cause problems, it's just the sort of thing that might.

[Red Iron Crown]

That's a bug? The program is working as they intended it to work.

The bugtracker has several categories of issues; bug, feature request, feedback, etc. Your issue is useful feedback and should be logged in the tracker as such.

[Farex]

Adding the fairing both increases the weight, and increases the side surface area (i.e. more surface for air to react against when it's anything other than directly prograde). Smoothing the air flow does nothing to eliminate the large surface area itself, it just minimises the drag for the surface area, and eliminates friction heating of the protected parts. Both of those factors require more control authority, and I'm guessing that it's just enough between them to push it over the limit of what you have available. I've yet to put much effort into big rocketry in 1.0, but past experience (pre-1.0) with things very like the rocket in your picture tells me that the thrust vectoring alone is frequently not enough for a 400+ tonne rocket. (Your boosters do seem well strutted, which rules out a different issue where the flexing of the mounting negates the thrust vectoring.) With really big payloads, I've used a stack of 4x 2.5m torque wheels (more typically on top of a 3.75m core + boosters, rather than 2.5m), and tail fins in the past.

Thanks for the explanation and you trying to help. I will try it out with bigger fintails on the second booststage (there are 4 small ones currently, will change them with big wings).

You can do it with struts and without the fairing, or you can do it with the fairing and without struts. But don't do it with both, at least not with struts going through the fairing wall. Or maybe it's something else, I don't know, but it looks like it's the struts causing you trouble.

Believe me, the struts in this picture are absolutely necessary. Without them, the Payload would break in half, either on the booster or at the dockingports. They don't seem to interfere with the aero, at least the overlay F12 says so.

The problem is that you're flying way too fast. Remove two of the LFBs and add a similar amount of fuel elsewhere, and the rocket will behave much better. A good launch TWR is 1.2-1.4 (or perhaps even lower, now that air pressure changes engine thrust), and it's rarely a good idea to let the TWR grow above 3 during the launch.

You know, there is the feature of controlling the thrust I keep my TWR usually around 2, just around the outer green line.

Edited May 5, 2015 by Farex
The [quote].....

[Giggleplex777]

These fairings are too damn heavy!

The Falcon 9 v1.1 fairing is 5.2m in diameter, 13.1m long and weighs 1.75 tonnes.

Source: http://www.spaceflight101.com/falcon-9-v11.html

If you were to build a similarly sized fairing in KSP, it weighs 12.5 tonnes, or more than 7 times heavier than the real life F9 one.

Combined with the amount of drag the fairings create, they actually hinder the performance of your rocket. Seriously, who thought that it was a good idea to make the fairings out of solid lead?

They should either make the fairings lighter or revert back to the way they were in 1.0.

Edited May 5, 2015 by Giggleplex777

[Zucal]

I hate the orange stripes they have. However, fairings do have their uses!

[Majorjim!]

These fairings are too damn heavy!

The Falcon 9 v1.1 fairing is 5.2m in diameter, 13.1m long and weighs 1.75 tonnes.

http://www.spaceflight101.com/uploads/6/4/0/6/6406961/4915000.jpg?433

Source: http://www.spaceflight101.com/falcon-9-v11.html

If you were to build a similarly sized fairing in KSP, it weighs 12.5 tonnes, or more than 7 times heavier than the real life F9 one.

http://i.imgur.com/3f2Va6m.png

Combined with the amount of drag the fairings create, they actually hinder the performance of your rocket. This is ridiculous. Seriously, who thought that it was a good idea to make the fairings out of solid lead?

They should either make the fairings lighter or revert back to the way they were in 1.0.

I couldn't agree more, they are unbeleiably heavy rendering them a hindrance...

I think it's clear they where an afterthought. We just have to hope that squad fix them,

[Brotoro]

These fairings are too damn heavy!

The Falcon 9 v1.1 fairing is 5.2m in diameter, 13.1m long and weighs 1.75 tonnes.

http://www.spaceflight101.com/uploads/6/4/0/6/6406961/4915000.jpg?433

Source: http://www.spaceflight101.com/falcon-9-v11.html

If you were to build a similarly sized fairing in KSP, it weighs 12.5 tonnes, or more than 7 times heavier than the real life F9 one.

http://i.imgur.com/3f2Va6m.png

Combined with the amount of drag the fairings create, they actually hinder the performance of your rocket. This is ridiculous. Seriously, who thought that it was a good idea to make the fairings out of solid lead?

They should either make the fairings lighter or revert back to the way they were in 1.0.

Wow. I didn't realize the mass of the KSP fairings was that ridiculously high.

Squad...please fix this.

And a kerbal snack for Giggleplex.

[r4pt0r]

These fairings are too damn heavy!

The Falcon 9 v1.1 fairing is 5.2m in diameter, 13.1m long and weighs 1.75 tonnes.

http://www.spaceflight101.com/uploads/6/4/0/6/6406961/4915000.jpg?433

Source: http://www.spaceflight101.com/falcon-9-v11.html

If you were to build a similarly sized fairing in KSP, it weighs 12.5 tonnes, or more than 7 times heavier than the real life F9 one.

http://i.imgur.com/3f2Va6m.png

Combined with the amount of drag the fairings create, they actually hinder the performance of your rocket. Seriously, who thought that it was a good idea to make the fairings out of solid lead?

They should either make the fairings lighter or revert back to the way they were in 1.0.

I have not gotten to use fairings in my career yet, but Im glad someone looked into some solid numbers on them. I too hope this gets tweaked.

[Giggleplex777]

More on the overweight fairings:

Here's the largest cargo bay:

It is 10.3m long and 3.75m in diameter (despite what the engineer's report says). 6.0 tonnes.

Now, here's a similarly-sized fairing:

7.4 tonnes(!).

If this isn't broken then I don't know what is.

Edited May 6, 2015 by Giggleplex777

[Farex]

I don't know which fairing you use, is it the biggest one? Because if you look at my pictures on page 3 you will see that this big fairing weighs ONLY 0,4t - 400 kg!

My Ship with fairing: 414,1t -> without fairing: 413,7t. I was using the 2,5m one. :/

[Giggleplex777]

I don't know which fairing you use, is it the biggest one? Because if you look at my pictures on page 3 you will see that this big fairing weighs ONLY 0,4t - 400 kg!

My Ship with fairing: 414,1t -> without fairing: 413,7t. I was using the 2,5m one. :/

Are you using 1.0.2? The fairings have mass now, and even a small 1.25m fairing weighs 1t.

[Farex]

Yes, these pictures were made yesterday. I am using 1.02. This was the 2,5m fairing.

€dit: The Stock-Engineer Report says so, Kerbal Eng Redux says it's something around 12t. OK, so forget the Stock Engineer Report or what is wrong with my game`?

Edited May 6, 2015 by Farex

[Starwaster]

Yes, these pictures were made yesterday. I am using 1.02. This was the 2,5m fairing.

€dit: The Stock-Engineer Report says so, Kerbal Eng Redux says it's something around 12t. OK, so forget the Stock Engineer Report or what is wrong with my game`?

KER isn't reporting correct mass for the fairing in the VAB. Neither does MJ.

Because, in the VAB the fairings don't actually have mass until they get to the real world. The stock report will show the correct fairing mass.

And I've been looking at numbers for real life fairings.

The lightest seems to be Space X's Falcon Heavy fairings at 1.75 tons for a 5.2m x 13m fairing but those aren't representative of other fairings using heavier materials.

Edit: Module Manager config fix

Using this on 11m x 3.75m resulted in a fairing mass of 0.8t (down from 7.425719t) (retrieved from craft file)

The original stock values had different UnitAreaMass values for each of the 3 fairing sizes instead of the flat rate below; an alternate means of correction is commented out below for UnitAreaMass

stock_fairing_fix.cfg

// values of 0.0069 to 0.008 will give you fairing density from Space X - Atlas/Delta
@PART
[*]:HAS[@MODULE[ModuleProceduralFairing]]
{
	@MODULE[ModuleProceduralFairing]
	{
		@UnitAreaMass = 0.0069
		//@UnitAreaMass *= 0.115
	}
}

Edited May 6, 2015 by Starwaster

[Brotoro]

If you want more data on real-world fairing masses, here are the dimensions and masses for the Titan IV payload fairings. These were constructed from aluminum. The are still available (I gather) as a "legacy" item for government projects (which I think refers to spy satellites) on newer launch vehicles, but I think most customers go with a more modern fiberglass option nowadays.

The vertical dimensions in the diagram below are in millimeters measured from the separation point (SP) line at the base. The diameter is 5.08 meters (the inner diameter was 5 meters...so the shell thickness was about 5 centimeters).

The names and masses of those fairings, from left to right:

50ft PLF: 3,600 kg

56ft PLF: 5,000 kg

66ft PLF: 5,500 kg

76ft PLF: 5,900 kg

86ft PLF: 6,300 kg

- - - Updated - - -

The narrow base of those fairings, by the way, was 10 feet (3.048 meters), so the masses of these fairings should be representative of fairings made from the 3-meter part in KSP (if the structural material is aluminum instead of fiberglass).

Edited May 6, 2015 by Brotoro

[Red Iron Crown]

In fairness KSP's engines and tanks are also much heavier than their real world equivalents, maybe they haven't advanced in materials science as much as we have.

Though I must say I agree that they seem too heavy now, in that the drag reduction is not worth the extra mass.

[Brotoro]

ADDENDUM: The fairing used on the Skylab launch (aluminum in construction) was 6.6 meters in diameter and 17.1 meters long. The complete assembly had a mass of 11,068 kilograms. So the Skylab fairing had roughly twice the mass per fairing surface area as the Titan IV fairings.

- - - Updated - - -

In fairness KSP's engines and tanks are also much heavier than their real world equivalents, maybe they haven't advanced in materials science as much as we have.

Though I must say I agree that they seem too heavy now, in that the drag reduction is not worth the extra mass.

in this case, for both reasons of realism and for reasons of gameplay (and we want to encourage people to use these cool fairings after Squad went through all the effort to put them in), I think it would be best if the masses of the KSP fairings were decreased to at least match the best real-world fairings...and give them a low drag coefficient, too, or however that gets calculated in the new aero model.

[mikegarrison]

and give them a low drag coefficient, too, or however that gets calculated in the new aero model.

Well, OK, but going back to the OP, launching a huge disk like that is not going to be much less draggy than launching that lander. I mean, just look at it. It would be like trying to push a Frisbee through the air wide-side-first.

[Brotoro]

Well, OK, but going back to the OP, launching a huge disk like that is not going to be much less draggy than launching that lander. I mean, just look at it. It would be like trying to push a Frisbee through the air wide-side-first.

In some cases, launching without a fairing (even if the fairings have proper masses) might work better than using a fairing. If you try to enclose a rectangular-planform rover in a circle, you are going to be enclosing a lot of wasted area...so a naked rover could have less drag than the large fairing. (This is why I built the rovers for my current Duna mission to have a circular planform so that they could fit in fairings once 1.0 came out.)

But it depends on how many parts the rover is made of and how draggy it all is. And if you don't have to worry about the aerodynamics ripping off parts of your spacecraft (as you do with the very fragile spacecraft we have in real life) you can get away without a fairing's protection.

[Van Disaster]

All tests are performed at 100% throttle using SAS to go straight up. All designs were also tested for gravity turns, and, while the fairing run did the turn the smoothest, none of them had serious issues performing up to a 45 degree turn. Obviously that's not efficient for an actual launch, but if they can do it at 3k they should be able to do it at 10+k.

I suspect that isn't helping - that's not how you fly a rocket profile anymore, start turning roughly straight off the pad ( or around 100m/s ballpark ).

That is if I'm reading it right that you're doing an old-stock style ascent.

Edited May 6, 2015 by Van Disaster

[Starwaster]

I suspect that isn't helping - that's not how you fly a rocket profile anymore, start turning roughly straight off the pad ( or around 100m/s ballpark ).

That is if I'm reading it right that you're doing an old-stock style ascent.

You're right, it's not a valid test. I performed 3 tests.

Three launches using a normal launch profile. (started turning ~250 altitude, 40% turn shape, turn end 60, target altitude 100 - Mech Jeb ascent profile)

Pure stock fairing = 883 delta-V remaining

No fairing = ~550 delta-V (ejected fairing and nose cone arrangement)

My mass adjusted fairings = 1108

The craft was a little needlessly complicated as I use two fairing bases to form an interstage and a cone on top (so, not quite stock because it was the Mk7 cone scaled up)

two large 3.75m tanks, the 3.75m engine cluster. Payload was a big orange tank with no fuel flow.

I'm going to go back and do it without the nose cone deal but I do believe even this experiment shows there is a definite savings in my delta-V budget that may not be apparent if you're just launching straight up because you're not spending enough time where fairings matter: In the lower atmosphere. If you're just launching straight up the ballistic coefficient becomes the deciding factor as you're just doing a ballistic lob out of the atmosphere.

(That is, there's a savings even with the stock fairings, so the answer to the title of the OP is: No, fairings are NOT useless. However, that said, they are too heavy by far)

Edited May 6, 2015 by Starwaster

[JoCRaM]

On the test I did I gained - but I'd estimate the fairing you have has roughly twice to thrice the cross-sectional area as the rover - it being round, to match the maximum diagonal of the rover, but the rover itself.

Of course, they've tweaked things several times over the last few days, so I don't know if my test is still valid.

[Superfluous J]

Dumb question time. What settings do Procedural Fairings use and can't we just copy those? I've not heard anybody complain that they're too heavy but - I'll admit - I haven't frequented that mod's thread since 1.0 came out as I personally would rather use stock fairings so long as they get the job done, which I think the stock fairings do in spite of their problems.

By "we" I mean the players who think the fairings are too heavy (myself included), by using a simple modman config.

[Starwaster]

Dumb question time. What settings do Procedural Fairings use and can't we just copy those? I've not heard anybody complain that they're too heavy but - I'll admit - I haven't frequented that mod's thread since 1.0 came out as I personally would rather use stock fairings so long as they get the job done, which I think the stock fairings do in spite of their problems.

By "we" I mean the players who think the fairings are too heavy (myself included), by using a simple modman config.

No you can't copy settings from the PF mod. The settings don't have the same names and the mod and stock fairings may not share the same TYPE of settings.

If you want to modify fairing mass then look at the Module Manager patch that I posted. Use that. Adjust it to your personal taste. The value is tons per square meter of fairing.

[Superfluous J]

If you want to modify fairing mass then look at the Module Manager patch that I posted. Use that. Adjust it to your personal taste. The value is tons per square meter of fairing.

Oh wow I totally missed that on a first read. I think I got distracted by the pictures in the post following yours.

Thanks for that. I think I'll try some different values (1/9th the mass just seems like too little, though I'll do some testing) but the structure is appreciated.

Also, I downloaded Proc Fairings to look at their configs and while you're right, I suggest anyone who hates the stock texture, replace the stock fairings_diff.dds with procfairings' fuselage1.dds. I don't "hate" the stock yellow line, but that black ] mark always makes me think something is clipping through the fairing.