The Vector: Your thoughts

[GoSlash27]

11 hours ago, Tweeker said:

Otherwise this argument just opens the door to all kinds of other problems, like a 1.25m poodle or a .625 meter swivel.

 I wouldn't consider either of these two examples to be a problem.

Mathematically speaking, you choose an engine based on it's mass, cost, Isp, and thrust. The diameter of it's mounting point doesn't factor into it. If you have too much engine for a job, making it skinnier doesn't help.

[monophonic]

12 minutes ago, GoSlash27 said:

Why would anyone want to cluster Reliants? Any larger form factor engine would outperform them in the same real estate.

Because then I can spend the 250 science points needed to unlock the Mainsail stack for other things.

I admit that the mainsail stack is superior in any other way of course. But so far in my 1.0.5 career the 6 Reliant + 1 Swivel cluster has been good enough. The second stage is powered by 6 Thuds in case you were interested. The reduction in height compared to an inline engine was very important to a few launches until I saved enough funds to fully upgrade the launchpad. This setup is enough for 10t to LKO with generous margins for my piloting. I have run the numbers for a Mainsail + Skipper version and that comes to 15t capability, which is a marked improvement. Since I recently unlocked the Skipper node to get the Poodle, I think I am about ready to switch over.

Of course this utility is also dependent on the style I run my current career. Which is very much a contract driven private launch company style of operation. I try to fit as many contracts with a launch as possible, and only unlock nodes when I cannot do the job with what I already have. Should I run a different style career another time I might beeline to the mainsail right away or stick to solids mostly. Only playtime will tell...

[Frozen_Heart]

People are completely missing the point of the Vector by asking for a 2.5m plate to be put on. The Vector was added without the plate to use on space shuttles as otherwise the plate stuck miles out the sides and made them look awful. If you added it back then you may as well take it out entirely and we'll go back to the skipper.

The only change i'd like to see with it is reducing the thrust by a third or so to be more like the skippers.

[GoSlash27]

Monophonic,

For a 10 tonne lifter, your best bet would be a Poodle upper and 3 kickbacks for the lower. A single skipper is just barely overloaded at that weight, but it could do 9 tonnes. All of these are available pretty early in the career.

 My point was that it's silly to compare a Vector to a cluster of Reliants. If a Mainsail is expensive to unlock, then how much worse is the Vector? If you have a job that's suitable for a Vector and you *have* a vector, then you're not going to look at a cluster of Reliants as an alternative. You're going to look at the Skipper and Mainsail because they're comparable.

Best,

-Slashy

 

[GoSlash27]

16 minutes ago, Frozen_Heart said:

People are completely missing the point of the Vector by asking for a 2.5m plate to be put on. The Vector was added without the plate to use on space shuttles as otherwise the plate stuck miles out the sides and made them look awful. If you added it back then you may as well take it out entirely and we'll go back to the skipper.

The only change i'd like to see with it is reducing the thrust by a third or so to be more like the skippers.

Frozen_Heart,

 Yeah, I've said this repeatedly. PorkJet stated this specifically in his DevNotes.

 Best,

-Slashy

[Temstar]

2 hours ago, GoSlash27 said:

Thrust isn't like Isp where "more is better". Any thrust beyond "enough" is simply wasted mass and cost.

No that's not quite correct either. While thrust by itself is not that useful, TWR is a critical number when it comes to engines. The fact is higher the TWR the better.

There's no such thing as an engine with too high of a TWR, there's only rockets that are too small for their engines.

[monophonic]

5 minutes ago, GoSlash27 said:

Monophonic,

For a 10 tonne lifter, your best bet would be a Poodle upper and 3 kickbacks for the lower. A single skipper is just barely overloaded at that weight, but it could do 9 tonnes. All of these are available pretty early in the career.

 My point was that it's silly to compare a Vector to a cluster of Reliants. If a Mainsail is expensive to unlock, then how much worse is the Vector? If you have a job that's suitable for a Vector and you *have* a vector, then you're not going to look at a cluster of Reliants as an alternative. You're going to look at the Skipper and Mainsail because they're comparable.

Best,

-Slashy

 

Yes, my lifter design and piloting skills could certainly be better.  The design I outlined gives around 4000ms^-2 dV for the ten tons. I guess I could trade a few tons of fuel to payload if I felt secure enough to launch with sane margins.  I guess I am still feeling the effects from the early launches that lost an engine or two to vectored exhaust - yet still made it to orbit. 

I have limited time to play so I like to bring that extra fuel along to do corrections should I mess up a burn or three. I usually get my injection burn mostly from the second stage - and sometimes it takes me as far as Minmus surface. But that's just my style - not everyone is made to be a caveman. 

[GoSlash27]

5 minutes ago, Temstar said:

No that's not quite correct either. While thrust by itself is not that useful, TWR is a critical number when it comes to engines. The fact is higher the TWR the better.

There's no such thing as an engine with too high of a TWR, there's only rockets that are too small for their engines.

Temstar,

 Not quite. T/W means nothing if both are more than is necessary for the job. For example, the Rhino vs. the Reliant. The Rhino has better t/w, but if a Reliant is sufficient you wouldn't use the Rhino.

 It's not a case of rockets being too small for their engines, but rather rockets being too big for their missions.

Best,

-Slashy

[swjr-swis]

This is sounding more and more like yet another fun and versatile part is going to be ripped because realism in a game.

One would think any kind of perceived OPness is already quite simple to resolve: dial it down when making it part of your design. This is already possible now, with stock game controls, without affecting anyone that happens to use its current full potential. Once it is nerfed however, the opposite can no longer be done and it's up to mods again.

Seeing where this is going, I'd like to put in the request early to have the current vector added as is to the historical parts pack, for those of us who still like to game in a game...

[Temstar]

6 minutes ago, GoSlash27 said:

It's not a case of rockets being too small for their engines, but rather rockets being too big for their missions.

But you know that's never going to be the case, since it's not like we have a lack of choice when it comes to small engines for small rockets. But go to the other end of the scale where you do need to lift large payloads then Vector and it's big brother Mammoth are king. So for a rocket that needs several thousand kN of thrust Vector and Mammoth gives you the required overall TWR with the least amount of engine.

Vector stands out particularly because it packs an enormous amount of thrust into a tiny physical package, and that package is explicitly made so it can be easily clustered. For a given physical footprint Vector or Mammoth (or even better, Vector glued onto Mammoth's empty centre space) gives you the most bang for the least amount of real estate.

I'm not saying Vector and Mammoth are overpowered. In fact given that the description specifically says they are technological breakthrough being the first staged combustion engines and the fact that they sit at the end of the tech tree even justifies their high thrust and relative high Isp in my mind. But calling their best in game TWR for bi-propellant engines as not an advantage is plain wrong.

[DrMarlboro]

I personally think it is perfect for what it was intended for, and that is shuttles. 

[Red Iron Crown]

1 hour ago, DrMarlboro said:

I personally think it is perfect for what it was intended for, and that is shuttles. 

I would have preferred bigger, stronger SRBs and weaker Vectors, both for authenticity and balancing reasons. Compare the thrust of a real Shuttle's LFO engine cluster to its SRB thrust, then look at three Vectors vs two Kickbacks. The real shuttle gets about 17% of its liftoff thrust from the LFO engines, the KSP equivalent gets about 70%.

[godefroi]

1 hour ago, Red Iron Crown said:

I would have preferred bigger, stronger SRBs and weaker Vectors, both for authenticity and balancing reasons. Compare the thrust of a real Shuttle's LFO engine cluster to its SRB thrust, then look at three Vectors vs two Kickbacks. The real shuttle gets about 17% of its liftoff thrust from the LFO engines, the KSP equivalent gets about 70%.

If you're arguing that we need bigger SRBs, then I'm 100% on board with you. I like to launch all my reasonable-sized rockets with a solid 1st stage, so a bigger one would be extremely welcome.

A larger SRB would allow us to scale Vector's thrust back a bit. I personally do not think it's especially necessary, but if I had to trade a 25% cut in Vector's thrust for a bigger SRB, I'd do it in a heartbeat.

One other thing (while we're on the topic of SRBs) that we need is a selectable thrust profile. A payload that results in a reasonable (~1.5) TWR at launch on top of a kickback also results in a difficult-to-control (~4-5) TWR at burnout. Even if we couldn't draw it ourselves, just being able to switch between "classic" and "tapered" would be plenty.

[Captain Sierra]

2 hours ago, Red Iron Crown said:

I would have preferred bigger, stronger SRBs and weaker Vectors, both for authenticity and balancing reasons. Compare the thrust of a real Shuttle's LFO engine cluster to its SRB thrust, then look at three Vectors vs two Kickbacks. The real shuttle gets about 17% of its liftoff thrust from the LFO engines, the KSP equivalent gets about 70%.

The real shuttle also has vastly different proportions that would require us to have 5m tanks for the external and 2.5m SRBs at least 40% taller than the kickbacks. Having done a more correctly proportioned shuttle with SpaceY, the Vectors arent so bad .... but the dV that vehicle packed was ridiculous when compared to the mission requirement. It could do a low-munar payload delivery and back with fuel to spare.

[NathanKell]

7 hours ago, swjr-swis said:

This is sounding more and more like yet another fun and versatile part is going to be ripped because realism in a game.

Uh....whaa? Realism isn't "everything I don't like". As I showed upthread, realism means size isn't a good metric anwyay, and in reality the Vector would be hilariously underpowered--and a bit large for its power, too!

[GoSlash27]

9 hours ago, Temstar said:

But you know that's never going to be the case, since it's not like we have a lack of choice when it comes to small engines for small rockets. But go to the other end of the scale where you do need to lift large payloads then Vector and it's big brother Mammoth are king. So for a rocket that needs several thousand kN of thrust Vector and Mammoth gives you the required overall TWR with the least amount of engine.

Vector stands out particularly because it packs an enormous amount of thrust into a tiny physical package, and that package is explicitly made so it can be easily clustered. For a given physical footprint Vector or Mammoth (or even better, Vector glued onto Mammoth's empty centre space) gives you the most bang for the least amount of real estate.

I'm not saying Vector and Mammoth are overpowered. In fact given that the description specifically says they are technological breakthrough being the first staged combustion engines and the fact that they sit at the end of the tech tree even justifies their high thrust and relative high Isp in my mind. But calling their best in game TWR for bi-propellant engines as not an advantage is plain wrong.

Temstar,

 The problem with that line of reasoning is that the Vector, when clustered, does not stack up well against the 3.75m engines. Well... excepting the Rhino which is a problem child at the moment.
The Twin Boar is an extremely economical lifter stage and the Mammoth does the same job as a comparable cluster of Vectors for half the price. You can stack up to 7 Vectors under the Kerbodyne tank and make a booster with excellent lifting capacity, but you're going to pay through the nose to do it. 
The Vector is just plain not economically feasible as a disposable stage; It's only really useful in designs where the engine comes home intact.

 AFA whether it's excellent t/w is an advantage or not is specific to the role in which it is used. If you mathematically analyze the process by which a stage is designed, you will see that thrust and weight both factor into the decision, but the t/w *ratio* does not.
 Less weight is always a good thing (all else being equal), but more thrust isn't necessarily good. Therefore the t/w ratio *in and of itself* is not an indication of whether an engine is the best option for a given job. If you have an engine with adequate thrust for a job and replace it with another engine with twice the weight and 4 times the thrust, you have put yourself at a disadvantage even though the second engine has twice the t/w ratio.

Best,

-Slashy

 

 

Edited January 14, 2016 by GoSlash27

[Gojira1000]

The vector is fine, especially in career where you pay the big bucks for it. And I can't see the use of sticking it on anything but shuttles (except in sandbox, where it works great on a dragster)

[regex]

On 12/9/2015 at 1:24 PM, NathanKell said:

Despite their looks, the Mammoth and Vector are really more modeled on the RD-171 and RD-191 respectively.

the Mammoth and Vector are really more modeled on the RD-171 and RD-191 respectively.

Vector [is] really more modeled on the RD-191

Vector ~ RD-191

<3

Stockalike Angara wooooo!  Too bad the 2.5m tanks all look like crap.

[Alshain]

8 hours ago, Red Iron Crown said:

I would have preferred bigger, stronger SRBs and weaker Vectors, both for authenticity and balancing reasons. Compare the thrust of a real Shuttle's LFO engine cluster to its SRB thrust, then look at three Vectors vs two Kickbacks. The real shuttle gets about 17% of its liftoff thrust from the LFO engines, the KSP equivalent gets about 70%.

This.  I mean, without SRB's the Vectors as-is is a must.  However, I too would much prefer shuttle style SRB's and weaker vectors.  It would be more balanced and the shuttles would look a lot nicer (more realistic anyway).  The SRB's are the tallest part of the space shuttle (keeping in mind the orange tank is offset) and the weenie little things in KSP don't even come close.

[GoSlash27]

10 hours ago, Frozen_Heart said:

The only change i'd like to see with it is reducing the thrust by a third or so to be more like the skippers.

 Frozen_Heart,

 I had the chance to crunch the numbers on this today, and I think you're dead- on. Not only does the Vector need a thrust reduction, but *all* of the 2.5m engines need it.

 This would rebalance the game considerably in a good way. The 2.5m engines are currently too close to the 3.75m engines and too far away from the 1.25m engines. The Vector is indeed overpowered for a shuttle replica in stock KSP, and the Skipper is just about ideal (except for the pesky butt plate).

 So the Vector should take on the stats of the Skipper and the Mainsail should take on the stats of the Vector (with the canonical tie-in to the 3.75m clustered engines). The Skipper would be derated to 65% of it's current thrust, weight, and cost making it actually useful in early career before facility upgrades.

The Rhino would need a total rebalancing, as it's currently an engine without a home. I would derate it to match the specs of the current Mainsail.

 Finally, the LV-T30 and LV-T45 need to be a little more expensive (about 30% or so) in order to make the jump to the Skipper more economically attractive.

Best,

-Slashy

[regex]

1 minute ago, GoSlash27 said:

  I had the chance to crunch the numbers on this today, and I think you're dead- on. Not only does the Vector need a thrust reduction, but *all* of the 2.5m engines need it.

 This would rebalance the game considerably in a good way. The 2.5m engines are currently too close to the 3.75m engines and too far away from the 1.25m engines. The Vector is indeed overpowered for a shuttle replica in stock KSP, and the Skipper is just about ideal (except for the pesky butt plate).

I disagree with this.  If anything what the Vector needs is more thrust to place it solidly between the Skipper and Mainsail.  Then the 3.75m engines should be drawn out for even more thrust. 

[GoSlash27]

2 minutes ago, regex said:

I disagree with this.  If anything what the Vector needs is more thrust to place it solidly between the Skipper and Mainsail.  Then the 3.75m engines should be drawn out for even more thrust. 

regex,

 I love the fact that we have an engine between the Skipper and mainsail, but that's not why the Vector exists. It exists to serve as a shuttle replica engine. As it sits now, it's overpowered in that role. Adding more power won't help.

 I'm not averse to having the big engines become even more powerful, but you've still got that chasm between the LV-T30 and Skipper to contend with. In the current situation, the Skipper comes along early in the career, but can't be used (at least not economically) in base facilities.

Best,

-Slashy

[regex]

1 minute ago, GoSlash27 said:

 I love the fact that we have an engine between the Skipper and mainsail, but that's not why the Vector exists. It exists to serve as a shuttle replica engine. As it sits now, it's overpowered in that role. Adding more power won't help.

Why is it overpowered?  Have it lift more stuff.  There is no reason why it can't also serve as the engine between the Skipper and Mainsail, and reducing its thrust just puts it in line with the Skipper, which already has too few uses (makes an excellent 5 ton reusable lifter but ... eh ... this isn't RO we're talking about so 5 tons on orbit is garbage).

[GoSlash27]

19 minutes ago, regex said:

Why is it overpowered?  Have it lift more stuff.  There is no reason why it can't also serve as the engine between the Skipper and Mainsail, and reducing its thrust just puts it in line with the Skipper, which already has too few uses (makes an excellent 5 ton reusable lifter but ... eh ... this isn't RO we're talking about so 5 tons on orbit is garbage).

 Because a shuttle that looks like a shuttle and lifts shuttle- like payloads from Kerbin doesn't *need* any more than a cluster of Skippers (and reasonable SRBs) to do the job.

^ Skippers, not Vectors.

 And I definitely disagree with your assessment of the Skipper in it's current state. It's actually the single most versatile and useful LF&O engine in the game currently. It's the best choice for boosters in the range of 2.4-7.0 tonnes, upper stages in the range of 18-44 tonnes, and SSTOs in the range of 1.5- 5.5 tonnes. It is the only engine in the entire game that works out to the lightest and cheapest option in all of these regimes.

 And I don't sneeze at 5 tonnes in orbit in career, *especially* early career. That's a huge amount if you use it efficiently. Especially when compared to the 2.2 tonnes an LV-T30 can put into orbit as a booster or the 1.5 tonnes of an LV-T30 SSTO.

Best,

-Slashy

Edited January 14, 2016 by GoSlash27

[Frozen_Heart]

If we had proper SRBs the Vector wouldn't need to be so madly powerful. As it is those are horribly underpowered.