The 1.25m engines suck... Bad.

[SlabGizor117]

Ok, let me clear some stuff up.  First, the cost is irrelevant as I'm playing on Sandbox for now.  Second, What I mean is that the vector is OP for it's size, not in a bad way.  It's super heave, powerful, as someone said, a 2.5m engine in a 1.25m package.  My point though is that it was too powerful to use instead of the Reliant or Swivel because those two were so weak.  

The rocket I was building was a 5 ton lifter, with a half size tank(I forget the name) and a 909.  Then it went to the first stage with the Reliant or Swivel.  Now, if it was a 2.5m rocket, and(I'm guesstimating here), say, a 20 ton payload, I would need a probe core, half size tank, skipper, decoupler, half tank and orange tank, and a mainsail, and that would most likely get to orbit.  Even if it didn't, all I would need to do is strap two other identical first stage boosters Delta-IV style(except with crossfeed).  I can't do that with 1.25m engines.  That's what I mean by TWR of 1.25m engines compared to 2.5m engine TWR.  I just can't build any reliable 1.25m lifters unless they turn into pyramid rockets with 4 LFBs and another 4 SRBs.  I shouldn't need that.  And I don't use the aerospike, mostly for aesthetic reasons.  

I understand they're cheap entry level engines, but they're so hard to lift payloads with.  If the Reliant were 250 and Swivel 220, that would probably be perfect.  I may be wrong, but it just seems like if I were to swap every 1.25m part with their 2.5m counterpart(all fuel tanks, 909-poodle, swivel-mainsail/skipper), it would work just fine.  I dunno, they just seem to underpowered to lift anything decently.

EDIT:  I'll do some testing and post back to see if there's any difference.

Edited March 28, 2016 by SlabGizor117

[Red Iron Crown]

27 minutes ago, SlabGizor117 said:

First, the cost is irrelevant as I'm playing on Sandbox for now.

Well yeah, they're going to "suck" if you play a mode where their biggest advantages (low cost, early availability) are negated.

[Plusck]

If you double the diameter of the stack, you quadruple the surface area of the each end. Keeping that "double size" ratio, you need to double the length of your stack too, so you multiply the volume by 8.

The 1.25m engines should therefore be one-eighth of the power of the 2.5m engines to maintain the same sort of capability. In fact they are much more powerful than that. 2.5m engines are much less heavy than pure scaling would imply, provide an increase in power which is greater than their increase in mass but is not equal to 8 times their 1.25m counterparts, and provide a slightly different mix of efficiencies in and out of the atmosphere. They therefore demonstrate the advantage of size, but when you build bigger you get all of the additional problems (slow maneuvring, heavy command pods, etc) that come with size.

And yes, the Vector is a slightly more efficient (but much more expensive) equivalent to the Mainsail in terms of thrust, weight and Isp. So it is very much the odd one out. And playing in sandbox (with no cost or unlocking concerns) maybe doesn't make its odd-one-out status as clear as it should.

[RocketBlam]

I guess I'll say this here... I don't really know why the Juno exists, although it's kind of fun early on. What I REALLY don't understand is why the Goliath exists. It's of no use for SSTOs, so... I just wonder why they included it. I guess some people use it, for big cargo planes, though I have no idea why you'd want a big cargo plane.

I'm not saying get rid of it, I just don't know why it exists. It would be like if Squad put a locomotive engine in the game. It's like... why do I want this...

[Kerbart]

5 hours ago, SlabGizor117 said:

Ok, let me clear some stuff up.  First, the cost is irrelevant as I'm playing on Sandbox for now.  Second, What I mean is that the vector is OP for it's size, not in a bad way.  It's super heave, powerful, as someone said, a 2.5m engine in a 1.25m package.  My point though is that it was too powerful to use instead of the Reliant or Swivel because those two were so weak.  

One might wonder why NASA doesn't use the Saturn 5 rocket for crew rotation runs on the ISS. Or the Space Shuttle for that matter. Of course you can choose to ignore cost. And you're absolutely right. If cost isn't an issue I'd be using Mainsails and Vectors for everything.

5 hours ago, SlabGizor117 said:

The rocket I was building was a 5 ton lifter, with a half size tank(I forget the name) and a 909.  Then it went to the first stage with the Reliant or Swivel.  Now, if it was a 2.5m rocket, and(I'm guesstimating here), say, a 20 ton payload, I would need a probe core, half size tank, skipper, decoupler, half tank and orange tank, and a mainsail, and that would most likely get to orbit.  Even if it didn't, all I would need to do is strap two other identical first stage boosters Delta-IV style(except with crossfeed).  I can't do that with 1.25m engines.  That's what I mean by TWR of 1.25m engines compared to 2.5m engine TWR.  I just can't build any reliable 1.25m lifters unless they turn into pyramid rockets with 4 LFBs and another 4 SRBs.

That depends. My standard shuttle to get a Mk1-2 pod into orbit utilizes a first stage with a Swivel and four Reliants as boosters. And an orbital stage with a terrier. Inadequate? Pray tell, how can 900 m/s DV in orbit be inadequate? It gets me to my transfer station (and back to Kerbin) for a meager 35,000 funds. And I'm talking about a fully decked out launch vehicle with escape tower and party lights. When I build that same configuration with a Skipper or a Mainsail I really have to scrape to stay under 50,000. 

And for unmanned satellites I hardly ever need anything else than a Swivel and two Thumpers. Why would I build something bigger when it's not needed?

5 hours ago, SlabGizor117 said:

I understand they're cheap entry level engines, but they're so hard to lift payloads with.  If the Reliant were 250 and Swivel 220, that would probably be perfect.  I may be wrong, but it just seems like if I were to swap every 1.25m part with their 2.5m counterpart(all fuel tanks, 909-poodle, swivel-mainsail/skipper), it would work just fine.  I dunno, they just seem to underpowered to lift anything decently.

That's why it's called rocket science. But really, that totally depends on what you're lifting. For large payloads they won't do of course. But the Vector and Mainsail are equally unfit for light payloads. There's nothing wrong with building big, but I do recommend trying the opposite for a while and build as small and as light as possible. You'll be amazed how far you can get with something super small.
One of the really hard parts in this game, especially in Sandbox mode, is fighting the urge to build big. Small can be challenging but it is very powerful. And when building small, Mr. Swivel and Mr. Reliant are your friends!

[KerikBalm]

On 3/28/2016 at 5:09 AM, bewing said:

The swivel and reliant are the very lowest tech engines on the tech tree for a reason, ya know. But if you look beyond just blasting a hole through the vacuum, IIRC the terrier has the best ISP of any LfOx engine. (It's also nice and short, which is convenient on lander designs. )

The 2.5m poodle has an Isp 5s higher.

Anyway, ignore the diameter of the vector... look at its mass. There are clearly applications where an LV-T45, or even more so the LV-909 are preferable, when lower mass and higher Isp are needed more than TWR.

That said.... if one just looks at stats like Isp and TWR, the 1.25m engines are not very good.

LV-909: 12.23 TWR, 345 Isp

Poodle: 14.56 TWR, 350 Isp

LV-T30/45: 17.53/13.59 TWR, 300/320 Isp

Skipper: 22.09 TWR, 320 Isp

Mainsail: 25.48 TWR, 310 Isp

But the 0.625m engines are just terrible, they are only used when you need a low mass:

Ant: 10.19 TWR, 315 Isp (less than half the TWR of the skipper, lower Isp... lower Isp and TWR than the LV-T45)

Spark: 18.35, 300 - Ok, this one is decent with its TWR ... it does outperform the LV-T30(TWR is nearly 6% higher, same vacuum Isp) if you ignore the atmospheric Isp (270 s 280).

The skipper matches or beats the LV-T45 in every way, the mainsail beats the LV-T30 in every way... both quite severely in TWR.

The poodle beats the 909 in every way...

Except total mass for all of the above

 

If I recall, for the skipper and poodle, they used to be worse than equivalent 1.25m engines, and reducing part count was their only advantage. Now they let you reduce part count, and give a performance boost... I don't know if they should... I feel like its just because they are deeper in the tech tree.

Buffing 1.25m engines to 2.5 or even 3.75m engine performance levels would make early career too easy I think... its super easy to get the dV needed for orbit with the new aero changes now.

[Frank_G]

Yeah the small engine sucks... preferringly air... I had lots of fun flying small aircraft with that engine.

[Temeter]

10 hours ago, SlabGizor117 said:

Ok, let me clear some stuff up.  First, the cost is irrelevant as I'm playing on Sandbox for now.  Second, What I mean is that the vector is OP for it's size, not in a bad way.  It's super heave, powerful, as someone said, a 2.5m engine in a 1.25m package.  My point though is that it was too powerful to use instead of the Reliant or Swivel because those two were so weak.  

The rocket I was building was a 5 ton lifter, with a half size tank(I forget the name) and a 909.  Then it went to the first stage with the Reliant or Swivel.  Now, if it was a 2.5m rocket, and(I'm guesstimating here), say, a 20 ton payload, I would need a probe core, half size tank, skipper, decoupler, half tank and orange tank, and a mainsail, and that would most likely get to orbit.  Even if it didn't, all I would need to do is strap two other identical first stage boosters Delta-IV style(except with crossfeed).  I can't do that with 1.25m engines.  That's what I mean by TWR of 1.25m engines compared to 2.5m engine TWR.  I just can't build any reliable 1.25m lifters unless they turn into pyramid rockets with 4 LFBs and another 4 SRBs.  I shouldn't need that.  And I don't use the aerospike, mostly for aesthetic reasons.  

I understand they're cheap entry level engines, but they're so hard to lift payloads with.  If the Reliant were 250 and Swivel 220, that would probably be perfect.  I may be wrong, but it just seems like if I were to swap every 1.25m part with their 2.5m counterpart(all fuel tanks, 909-poodle, swivel-mainsail/skipper), it would work just fine.  I dunno, they just seem to underpowered to lift anything decently.

EDIT:  I'll do some testing and post back to see if there's any difference.

Your complaint is a bit distracting in that regard. The Vector is a bit overpowered, but that's not because of it's size. Frankly, it's far too powerful for actual 1.25m stacks, and throttling down turns into a disadvantage because of it's weight. The actual reason for - and advantage of - it's small diameter is found in the application in space shuttles. Ridiculous vectoring and high sea level ISP at the superb T/W of a Mainsail (despite being a bit lighter) are what make the engine somewhat overpowered. IMO the vector isn't really a problem in itself, tho. I really like it's design, using orange tank+adapter looks like a delta heavy.

For curiosities sake, I just went into the VAB, and I was remembered of what you are talking about. There is a bit of a gap between the point where 1.25m stacks can lift stuff, and where 2.5m becomes reasonable. For 5 tons, a skipper is basically single stage to orbit, while you need more complex construction with LV-T45/30.

Personally I like to see the LV-T's as low tech, low complexity and low price engines. That meaning is of course a bit lost in sandbox. I'd say rather try combining the LV909/45/30 with SRB's, always had fun doing that and it really felt like the Kerbal thing to do to me:

For 5 tons, use an LV-909 + FT400 tank as an upper stage, below it an LV-45 + 2xFT800. Then add two BACC's (mid size SRB) on radial decouplers. Now here's the interesting thing: If you lower their thrust limit to 60%, you can use both boosters and the LV-45 in the first stage without throttling down. Means you get full engine vectoring, and when the SRB's are empty, you just dump them. That's how many real life rocket designs work.

Of course you could also just use a vector and some 2.5m tanks and get single stage to orbit with some d/V left. Easy, simple. But that's also possible with a skipper.

EDIT: Just checked it out, and no, seems like you want to keep the boosters thrust limit at 100% for full efficiency. Guess this isn't reasonable, but rather Kerbal rocket design. Time in RSS taught me too much sensibility. :3

Edited March 29, 2016 by Temeter

[SlabGizor117]

21 hours ago, Kerbart said:

That's why it's called rocket science. But really, that totally depends on what you're lifting. For large payloads they won't do of course. But the Vector and Mainsail are equally unfit for light payloads. There's nothing wrong with building big, but I do recommend trying the opposite for a while and build as small and as light as possible. You'll be amazed how far you can get with something super small.
One of the really hard parts in this game, especially in Sandbox mode, is fighting the urge to build big. Small can be challenging but it is very powerful. And when building small, Mr. Swivel and Mr. Reliant are your friends!

Actually, that's exactly what I was trying to do;  a 5 ton lifter.  My main problem is that after the 5 tons worth of fuel, and the upper stage with an FL-T400 and a 909, I couldn't build a decent first stage under it.  I am trying to build small with it, I was trying to limit myself to 1.25 for the 5-10 ton lifters, but I just can't do it, there's such a huge gap between the 30/45 and 2.5m/Vectors.  I still haven't found a solution with my first stage, because I am trying to build small and also aesthetically.  That's kinda why I'm refusing the "moar boosters" mentality.  Sure I can throw a bunch of SRBs on and call it done, but like you said, I'm trying to build small and I also prefer LFBs to SRBs.  I dunno, SRBs just seem clunky, like using duct tape to fix a problem.  "Just duct tape it, it'll work fine" - "Just throw some SRBs on it, it'll work fine".  It just seems like SRBs are a quick fix that would be more properly solved with LFBs.  I guess because of their inversatility(real word?) and uncontrolability.

[Waxing_Kibbous]

Maybe I'm not understanding the problem, but with all the engines on one stage I get 1.48 TWR on the launchpad. As long as you have a Swivel in the middle you can use either Reliants or SRBs and still get control :

[Red Iron Crown]

@Waxing_Kibbous Showing Vacuum stats there.

[Kerbart]

42 minutes ago, SlabGizor117 said:

Actually, that's exactly what I was trying to do;  a 5 ton lifter. 

Would you mind sharing a picture of said lifter?

[Waxing_Kibbous]

4 minutes ago, Red Iron Crown said:

@Waxing_Kibbous Showing Vacuum stats there.

I did actually launch it and it lifted fine- again according to KER it had around 1.48 TWR at liftoff- of course that could explain why I always have discrepencies between the VAB and the pad

Edited March 30, 2016 by Waxing_Kibbous

[Red Iron Crown]

2 minutes ago, Waxing_Kibbous said:

I did actually launch it and it lifted fine- again according to KER it had around 1.48 TWR at liftoff

How did the second stage do? The Swivel suffers more in atmo and is more marginal in TWR, were you far enough up by then that that didn't matter?

[Kerbart]

Here's my "Apollo" (stop laughing) low orbit crew shuttle. Orbital stage (+ escape tower) weighs 12,500 kg. Launches just fine using Reliants (and one Swivel in the center stage, for control and since it has better I_sp higher up)

[samstarman5]

23 hours ago, Kerbart said:

That's why it's called rocket science. But really, that totally depends on what you're lifting. For large payloads they won't do of course. But the Vector and Mainsail are equally unfit for light payloads. There's nothing wrong with building big, but I do recommend trying the opposite for a while and build as small and as light as possible. You'll be amazed how far you can get with something super small.
One of the really hard parts in this game, especially in Sandbox mode, is fighting the urge to build big. Small can be challenging but it is very powerful. And when building small, Mr. Swivel and Mr. Reliant are your friends!

With satellites about to become really relevant shortly after 1.1, then those lighter engines are going to be very useful longer in career. So it would definitely pay to go back to the roots and play with the Reliant and Swivel engines to get more familiar with what they can do. After all, there are those of us who got to the Mun and back with only those to use.

[Dispatcher]

The engine launch graph linked in my sig line will probably be outdated when KSP version 1.1 is out, but you might be surprised how some of the engines compare with each other in their respective classes and modes.

I suspect that some engines will be further tweaked and rebalanced when version 1.1 hits.

[Stoney3K]

On 29/03/2016 at 5:31 AM, RocketBlam said:

I guess I'll say this here... I don't really know why the Juno exists, although it's kind of fun early on. What I REALLY don't understand is why the Goliath exists. It's of no use for SSTOs, so... I just wonder why they included it. I guess some people use it, for big cargo planes, though I have no idea why you'd want a big cargo plane.

You can say the same thing about the Wheesley which is not really useful for SSTOs either.

Unless there are going to be career goals that say "Land this payload or this tourist on location X", there is absolutely no use for subsonic aircraft. Which raises the question what the stock Mallard is even used for.

I mean, airliner parts are cool, but I'd like to do some more things with them than just circling around the pattern at KSC runway 09/27. That gets boring pretty quick.

[Temeter]

6 hours ago, SlabGizor117 said:

Actually, that's exactly what I was trying to do;  a 5 ton lifter.  My main problem is that after the 5 tons worth of fuel, and the upper stage with an FL-T400 and a 909, I couldn't build a decent first stage under it.  I am trying to build small with it, I was trying to limit myself to 1.25 for the 5-10 ton lifters, but I just can't do it, there's such a huge gap between the 30/45 and 2.5m/Vectors.  I still haven't found a solution with my first stage, because I am trying to build small and also aesthetically.  That's kinda why I'm refusing the "moar boosters" mentality.  Sure I can throw a bunch of SRBs on and call it done, but like you said, I'm trying to build small and I also prefer LFBs to SRBs.  I dunno, SRBs just seem clunky, like using duct tape to fix a problem.  "Just duct tape it, it'll work fine" - "Just throw some SRBs on it, it'll work fine".  It just seems like SRBs are a quick fix that would be more properly solved with LFBs.  I guess because of their inversatility(real word?) and uncontrolability.

SRB's are a 'quick fix' in the real world, usually used to solve low thrust levels of the core engines during the start. Look at ariane 5, the most important commercial rocket, and SLS, which is gonna be the most powerful rocket since the Saturn 5.

[RocketBlam]

On 3/29/2016 at 8:31 PM, RocketBlam said:

I guess I'll say this here... I don't really know why the Juno exists...

I want to amend my statement. The Juno isn't much good for making an SSTO. It is, however, fun for the early days of career. You can still use it for low-altitude stuff. I've been having some fun with this, the Hopper, which was designed to just fly around the KSC and get science from all the building biomes. It is also useful for flying to nearby biomes, like Grasslands, Highlands and the mountains. this is before you get wheels. This is before I even got solar panels. It's a surprisingly easy and fun craft to fly.

[Nich]

10 hours ago, SlabGizor117 said:

Actually, that's exactly what I was trying to do;  a 5 ton lifter.  My main problem is that after the 5 tons worth of fuel, and the upper stage with an FL-T400 and a 909, I couldn't build a decent first stage under it.  I am trying to build small with it, I was trying to limit myself to 1.25 for the 5-10 ton lifters, but I just can't do it, there's such a huge gap between the 30/45 and 2.5m/Vectors.  I still haven't found a solution with my first stage, because I am trying to build small and also aesthetically.  That's kinda why I'm refusing the "moar boosters" mentality.  Sure I can throw a bunch of SRBs on and call it done, but like you said, I'm trying to build small and I also prefer LFBs to SRBs.  I dunno, SRBs just seem clunky, like using duct tape to fix a problem.  "Just duct tape it, it'll work fine" - "Just throw some SRBs on it, it'll work fine".  It just seems like SRBs are a quick fix that would be more properly solved with LFBs.  I guess because of their inversatility(real word?) and uncontrolability.

You are so wrong on SRBs.  Using LFBs are the equivalent of using $100 dollar gold plated Monster HDMI cables when a $2 chinese cable will work just fine.

[theorigin]

I dont think those engines suck. I am currently "replaying" career mode in 1.0.5 (waiting for hypetrain 1.1 to arrive), and had some very interesting experiences so far with all the low tech engines. Right now i am doing some very own challenges by building rockets which fit exactly the deltaV amount of the deltaV map (here), i.e going to land on the mun with a rocket with exactly 5150deltaV. All done with LVL-909 and LV-T45 and the only mod i use is KER for basic information (mass/speed etc.) In the end on my way back from Mun to kerbin, i had about 19seconds of fuel left (180deltaV), had no orbit around mun and was about 700k km away from aerobraking into kerbins atmosphere. So instead of breaking, i accelerated towards kerbin for 8seconds, slingshotted around it, just to hit the mun on the other side again, which then  slingshotted me again (after 10seconds of reverse thrust) towards kerbin but now with an periapsis of 33k meters. Two more orbits and a small burn of the left fuel later, i was splashing down safely into the kerbin ocean with 350 science on board.

What i want to say, even with proper planning and exact calculations, your results may vary (bad vectoring, missing burn windows and stuff) and you have to improvise or just engineer the crap out of your given tools to hit your goal. Its possible, but sometimes, you need to "think around the corner" (german saying). And if all fails - just add more boosters

[Spaceception]

1 hour ago, InterCity said:

I don't think 1,25m engines suck. On the contrary, i find the aerospike to be one of the best engines in-game, and swivel is a good engine for smaller missions. Granted, compared to the mainsail they suck as lower stage engines. Take them to orbit, though, and you'll see their true power.

Until then, you basically have one five options:

1. Boosters!
2. More boosters!
3. Ridiculous amount of boosters!
4. Ludicrous amount of boosters!
5. FIRE ALL THE BOOSTERS!!1!!1!1!!1!!1!!!1!!1

GET THE POWER OF PLAID BOOSTERS!!!!!111!!!

Just now, Kerbart said:

Here's my "Apollo" (stop laughing) low orbit crew shuttle. Orbital stage (+ escape tower) weighs 12,500 kg. Launches just fine using Reliants (and one Swivel in the center stage, for control and since it has better I_sp higher up)

You don't have onion staging or anything? You could probably get more efficient that way.

[Kerbart]

1 hour ago, Spaceception said:

You don't have onion staging or anything? You could probably get more efficient that way.

The four outer boosters feed into the central core and they drop off first (Vostok/Soyuz style). Does that count as onion staging?

I used to use a Skipper and Jumbo tank for this launcher but the Reliants/Swivel get the job done for considerably less money.

Edited March 30, 2016 by Kerbart

[MatttheCzar]

On 3/29/2016 at 10:31 PM, RocketBlam said:

I guess I'll say this here... I don't really know why the Juno exists, although it's kind of fun early on. What I REALLY don't understand is why the Goliath exists. It's of no use for SSTOs, so... I just wonder why they included it. I guess some people use it, for big cargo planes, though I have no idea why you'd want a big cargo plane.

I'm not saying get rid of it, I just don't know why it exists. It would be like if Squad put a locomotive engine in the game. It's like... why do I want this...

I think the Juno is the best jet engine: efficient, easy to cluster, decent top speed, and keeps its thrust at high altitude.  As for the goliath, people like playing Kerbal Plane Sim, myself included.