Poodle Vs LV-T30

[Red Iron Crown]

The problem is that there are other engines with the same vacuum Isp as the Poodle with better TWR (aerospike, LV-909), so the Poodle is rarely, if ever, the best choice. Even engine length isn't a big factor, both of those other engines are quite short, too.

[Sky_walker]

Theres a weird kind of thing here where the Nuclear engine is so good I use it for practically everything past Kerbin. It be nice if I had to make a choice more often.

This.

(10 char)

[rkman]

The problem is that there are other engines with the same vacuum Isp as the Poodle with better TWR (aerospike, LV-909), so the Poodle is rarely, if ever, the best choice.

Assuming you replied to me: i'm aware of that, i am trying to figure out why that is and how it could be fixed.

I don't use the aerospike because i think it's to cheaty, but I'm pretty sure the 909 outperforms the Poodle since the 909 has been buffed a few times.

How do you think the Poodle would best be fixed to regain its niche?

[Red Iron Crown]

Assuming you replied to me: i'm aware of that, i am trying to figure out why that is and how it could be fixed.

I don't use the aerospike because i think it's to cheaty, but I'm pretty sure the 909 outperforms the Poodle since the 909 has been buffed a few times.

How do you think the Poodle would best be fixed to regain its niche?

I was replying to you, sorry I didn't quote you to make it clear.

IMO, the Poodle should get a vacuum Isp buff, to ~450s. That would make it useful in more situations, and might displace the LV-N in some interplanetary scenarios.

[Sky_walker]

IMO, the Poodle should get a vacuum Isp buff, to ~450s.

450? Wouldn't it make it one of the best engines in a game? It doesn't make any sense from a logical point of view.

Poodle main advantage is in it's large gimbal range. If anything - I'd welcome slight increase in vacuum Isp for a decrease of atmospheric Isp, but nothing radical.

IMHO a good way to balance it would be by giving a 10 degree gimbal range or something around that - it'd make Poodle an outstanding engine for landers. You could forget about SLS or RCS modules on these.

[Red Iron Crown]

450? Wouldn't it make it one of the best engines in a game? It doesn't make any sense from a logical point of view.

Poodle main advantage is in it's large gimbal range. If anything - I'd welcome slight increase in vacuum Isp for a decrease of atmospheric Isp, but nothing radical.

I find gimballing almost useless. Almost always better to choose a lighter engine and add reaction wheels, a good example of this is LVT-45 vs LVT-30 + wheel. Gimballing just isn't a consideration for me when choosing an engine, like presence or absence of an alternator. It's nice to have, but not a deal breaker.

450s of vacuum Isp would make it the third highest in the game, to match it having the third worst TWR. I see nothing particularly illogical about it.

Edited July 14, 2014 by Red Iron Crown
Typo

[Jouni]

The problem is that the different engine series are not balanced with each other. Within each series (LV, Rockomax, Kerbodyne), the engines are balanced and all of them are useful. When you start mixing engines from different series, the Kerbodyne engines beat the LV engines, which in turn beat the Rockomax engines.

Maybe Squad will fix this in 0.24. If you can buy a Poodle for the price of three LV-909s, the engine becomes quite useful.

[Sky_walker]

I find gimballing almost useless.

I don't. You need to fly ships that rely on gimbals differently than these with RCS or reaction wheels, never the less - gimbals work just fine.

Don't look at the game from purely subjective perspective. Especially when you try to talk about balance. Noone will balance the game especially for you

450s of vacuum Isp would make it the third highest in the game, to match it having the third worst TWR. I see nothing particularly illogical about it.

It doesn't lay in line with other engines from it's group. And there's absolutely no reason to have such a high Isp for an engine that's basically made for probes / landers.

[Red Iron Crown]

I don't. You need to fly ships that rely on gimbals differently than these with RCS or reaction wheels, never the less - gimbals work just fine.

Don't look at the game from purely subjective perspective. Especially when you try to talk about balance. Noone will balance the game especially for you

I don't expect it to be balanced just for me, I just don't like to make my opinion sound like universal fact. I can only offer my views on how it fits into my playstyle.

It doesn't lay in line with other engines from it's group. And there's absolutely no reason to have such a high Isp for an engine that's basically made for probes / landers.

Huh, I never think of it as a lander engine, more of an orbital maneuver engine for big ships. When you say "lay in line with other engines in its group", what do you mean exactly?

[r4pt0r]

i always use the poodle for landing on the mun

[Laie]

IMO, the Poodle should get a vacuum Isp buff, to ~450s. That would make it useful in more situations, and might displace the LV-N in some interplanetary scenarios.

Won't the reality types cry in pain? IIRC, ~390 is as good as it gets in real life. However, what about shedding some weight? If it was no heavier than it's equivalent thrust in poodles, or (god forbit) even a little lighter, that would go a long way. IMO.

[Red Iron Crown]

Won't the reality types cry in pain? IIRC, ~390 is as good as it gets in real life. However, what about shedding some weight? If it was no heavier than it's equivalent thrust in poodles, or (god forbit) even a little lighter, that would go a long way. IMO.

There are real life engines with ~450s of vacuum Isp, many of them, in fact. I don't think the realism types would object too much. The problem with giving it a better TWR is that there are already engines in that category, like the aerospike or LV-909. Raising its Isp would put it in a new niche that isn't filled currently.

[Master Tao]

IIRC, vacuum Isp of 390s is KSP's version of 450s to slightly compensate for the reduced scale. Still, it's a game, so bumping the Poodle up a bit would make it more interesting.

[Overfloater]

I think motors that can perform SSTO are very practical:

Bad? hah. Definitely worth something. I like using it on interplanetary drives and big moon-landers.

But more importantly it looks cool ;-)

p.s. if you all want to make it even more efficient that fine with me!!!

Edited July 14, 2014 by Overfloater

[nli2work]

if you don't object to mods, I made these

[SciMan]

Here's a few chemical fuel engines that have good ISP IRL. To be honest, I don't understand the "ISP glass ceiling" effect that bipropellant chemical engines in stock KSP seem to have, and think it should change a little bit

The RS-25 Space Shuttle Main Engine (SSME)burns LH2 and LOX to get an ISP of 366s at sea level and 452.3s in space. It's got a lot of thrust for its weight, but it's very complex because it uses a staged combustion cycle, which is part of what makes it so expensive.

The RL-10 used in the Centaur upper stage is another LH2-LOX engine. Upper stage engine, so no data for sea level ISP, it gets an ISP of 450s to 465.5s in space. It's a simple, reliable, 10kN thrust expander cycle engine that hasn't changed much for the past 30 years at least.

The RS-68 is used in the first stage of the Delta IV, which is unusual for a LH2-LOX engine. It gets an ISP of 365s at sea level and 410s to 412s in space. It's less efficient than the SSME or the RL-10 because it uses a gas generator cycle, and likely also because it's nozzle is optimized for use as a first-stage engine.

There was also some research into engines that would burn LH2 fuel and a mix of Liquid Florine and LOX as oxidizer, but the Florine was simply too reactive, and would ignite on contact with almost anything, including the aluminum structure of the fuel tanks! If they could have been built, they were predicted to have something like 500-600s ISP in space.

Here's the KSP engines that I think translate well to Apollo-program era engines (yes, that includes the RL-10)

Mainsail = F1 (S-IC stage of Saturn V)

Skipper = J-2 (S-II stage of Saturn V, also S-IVB stage of Saturn V and Saturn IB)

Poodle = AJ-10 (Apollo Service module's Service Propulsion System engine)

48-7S = TR-201 (direct successor to the Lunar Module Descent Engine)

LV-909 = RL-10 (Centaur upper stage engine)

LV-T30 = LR-87 (Titan missile 1st stage, as used to launch Gemini capsules)

LV-T45 = H-1 (1st stage of Saturn IB, rebranded as RS-27 and used on the first stage of Delta II and Delta III rockets)

Edited July 14, 2014 by SciMan

[Jouni]

Here's a few chemical fuel engines that have good ISP IRL. To be honest, I don't understand the "ISP glass ceiling" effect that bipropellant chemical engines in stock KSP seem to have, and think it should change a little bit

As other people have already said, it's a game balance issue. The delta-v requirements of going anywhere are so low that we don't need more efficient/realistic engines and fuel tanks. The situation might change, if the game switched to bigger planets in a bigger solar system.

[hydropos]

I just set up a spreadsheet to calculate ∆V for different engines, and the poodle loses almost across the board. It only beats the LV-T30 when you get below a TWR of 0.5, and it's marginal even then. The same can be said for the LV-909, and both are outclassed by the aerospike for every TWR. The spreadsheet also showed that the NASA engines were clear choices for anything with a TWR > 1.

As other people have already said, it's a game balance issue. The delta-v requirements of going anywhere are so low that we don't need more efficient/realistic engines and fuel tanks. The situation might change, if the game switched to bigger planets in a bigger solar system.

I've been playing the Real Solar System mod using stock parts, so this relates to me. I don't use mod parts for two reasons: First, modded parts put many people off (I like posting my craft). Secondly, balance comes down to which mods I use, which feels like cheating.