[1.3.0] OPT Space Plane v2.0.1 - updated 29/07/2017

[Bakase]

These parts seem way too OP.

The Aerospike is massive, yet only 3.5 tons.

Many large parts weigh too little. The most massive plane parts hardly weigh anything.

The Scramjets seem the most OP of all. They can provide like 1,500kN of thrust for those tiny little 2.5ton things. In FAR, at least.

Stock parts definitely lack a scram jet and such, and it's nice to have something better than the turbofan, and better than rapier without having to run on ox, but it's too good. It gives like double the thrust that it should.

I don't think any balance pass has yet been done -- none of these parts are final. Also, you say that the most massive plane parts hardly weigh anything -- would this have something to do with the fact that they are hollow?

[gilflo]

OPT J61 scramjet engine is fantastic to use

http://forum.kerbalspaceprogram.com/threads/131211-Starblaster-Cargo

[TheReaper]

Personelly i dont care for the realism part, and ill reject the "balance" updates. KSP is a simulator game but with mor emphasis on the fun. Some people may seek fun in realism, but i dont.

[innociv]

I don't think any balance pass has yet been done -- none of these parts are final. Also, you say that the most massive plane parts hardly weigh anything -- would this have something to do with the fact that they are hollow?

Hollow or not, it needs a stronger structure to support what is attached to it, what it's carrying, etc.

I think I'll go in an edit some balance changes when I get around to it.

There's also a lot of bugs with parts that clip wanting to jitter around.

Very cool looking and useful parts, but I hope that stuff is fixed soon.

[M_Ouellette]

Personelly i dont care for the realism part, and ill reject the "balance" updates. KSP is a simulator game but with mor emphasis on the fun. Some people may seek fun in realism, but i dont.

I couldn't have said it better myself. But if "Balance" changes are made I am not adverse to going into the config files and changing things to my liking.

[innociv]

Yes, that's fine. No one says you can't "cheat".

But I feel like parts packs like these should be relatively balanced around stock to start with, and not require editing the other way around to make them fair.

[AccidentalDisassembly]

Yes, that's fine. No one says you can't "cheat".

But I feel like parts packs like these should be relatively balanced around stock to start with, and not require editing the other way around to make them fair.

I see what you mean, but I would simply add that some stock values for parts are a bit crazy, and I think there's a lot of leeway to make parts lighter while still making them perfectly reasonable.

Crazy stock mass actually becomes a problem under some conditions, too, like if you want to use FAR. Things become (effectively) really, really heavy all of a sudden in FAR, and you have to get a 4-ton plane with gigantic wings going something like 180mph just to lift off.

Just by way of example: a stock jet engine weighs 1.5 TONS. That's 3,306 pounds. It's roughly 4 feet (~49 in) in diameter and maybe 4 feet long. That's kind of big, but random googling revealed that a J40 turbojet from 1953, which is 25 feet long and 40 inches in diameter, weighs about 3500. Maybe the stock part is just supposed to represent the tail end of a long engine like that, but it creates problems with the center of mass of craft that are really only resolved by cockpits being equally ludicrously heavy to balance it out.

I think so long as an effort is made so that the parts don't become super overpowered if they're low-weight (e.g. huge TWR or something), then there's a good case to be made that stuff should really be lighter than it is even when you're not hell-bent on "realism" per se.

[blowfish]

Just by way of example: a stock jet engine weighs 1.5 TONS. That's 3,306 pounds. It's roughly 4 feet (~49 in) in diameter and maybe 4 feet long. That's kind of big, but random googling revealed that a J40 turbojet from 1953, which is 25 feet long and 40 inches in diameter, weighs about 3500. Maybe the stock part is just supposed to represent the tail end of a long engine like that, but it creates problems with the center of mass of craft that are really only resolved by cockpits being equally ludicrously heavy to balance it out.

In 1.0.x the CoM of the jets has been offset so that it's actually in front of the engine nozzle, as it should be. Not sure how reasonably it is placed though.

[AccidentalDisassembly]

In 1.0.x the CoM of the jets has been offset so that it's actually in front of the engine nozzle, as it should be. Not sure how reasonably it is placed though.

Huh... didn't know that. Still though, I think the general point stands even if the jet engine isn't a perfect example, or maybe everyone just needs to start throwing around CoM offsets on their engines or something =)

[Starwaster]

Huh... didn't know that. Still though, I think the general point stands even if the jet engine isn't a perfect example, or maybe everyone just needs to start throwing around CoM offsets on their engines or something =)

Yes, they do and I've suggested it myself long before 1.0

[M_Ouellette]

Yes, that's fine. No one says you can't "cheat".

But I feel like parts packs like these should be relatively balanced around stock to start with, and not require editing the other way around to make them fair.

Fair in comparison to what? We aren't competing here, we are playing a game based in an unrealistically small solar system against no-one but ourselves, so the accusation of "cheating" sounds at the least, absurd. In any event each to his own. I agree with you though, simply for the sake of a seamless fit with the existing game, that values should be proportioned accordingly.

[Balto-the-Wolf-Dog]

Personally I'd be inclined to balance the SCRAM by limiting it to being a SCRAM so it doesn't produce any thrust at all at subsonic speeds, orbiter XR-2 ravenstar style. That or perhaps leave its low atmosphere functionality but limit it to turbojet-reasonable thrusts until in a realistic SCRAM functionality envelope

[M_Ouellette]

Personally I'd be inclined to balance the SCRAM by limiting it to being a SCRAM so it doesn't produce any thrust at all at subsonic speeds, orbiter XR-2 ravenstar style. That or perhaps leave its low atmosphere functionality but limit it to turbojet-reasonable thrusts until in a realistic SCRAM functionality envelope

I think the later would be preferable for a space saving aspect maybe with narrow peak efficiency ranges in the operating envelopes of the dual modes, that would give advantages and disadvantages to using a hybrid engine. If that's doable of coarse.

[ZodiusInfuser]

Ok, I finished the new parts finally,,,

http://i.imgur.com/Cd6lqJ8.png

I personally think they turned out great and pretty useful as well, but because it cannot connect to any stock parts, it just lack alot of versatility compare to the current k parts.

Still, the upside is you can build some very smooth looking cargo ship, so ill add them as 6 new parts and it wont be replacing the k parts.

This is a mission i deploy a space station with these parts as well as Mk4 2.0 engines.

http://imgur.com/a/B5eb7

These new parts a looking great! Just what I wanted from a larger cargo capacity bay!. Btw, is the new JX(tended ) profile similar to what you showed earlier when concepting it? I'm trying to judge whether it would fit 3.5m parts. Also if that's a flat bottom I'm seeing then this profile is asking for a rear cargo ramp for driving rovers in and out!

[innociv]

Personally I'd be inclined to balance the SCRAM by limiting it to being a SCRAM so it doesn't produce any thrust at all at subsonic speeds, orbiter XR-2 ravenstar style. That or perhaps leave its low atmosphere functionality but limit it to turbojet-reasonable thrusts until in a realistic SCRAM functionality envelope

Yeah, I'm not saying it should be the stats of 2 turbojets or something.

I don't like that pretty much the only way to make a SSTO in 1.0+ is to use rapiers. I miss being able to use turbojets+LV-N...

Having the scramjet be optimal at mach2.5-mach6 but have less thrust than a single turbojet under mach2.5 would be a good way to balance it.

Right now it's not only better than 2 turbojets at mach0, but it's even more better at mach3+, which is just not good.

Edited August 12, 2015 by innociv

[K.Yeon]

That looks AWESOME! What are you calling the new fuselage profile?

As before, I'm happy to write part descriptions again...

Can't wait for the new update.

Thanks! Definitely need descriptions! Im thinking of calling the new parts J-XWB

After testing out different plane designs I find that there's a need for some more parts.

Just an unordered list of what came into my mind:

- add a MK2-J adapter without offset MK2 node (-> which leads to offset CoM, very difficult to compensate)

- add a simple J-K adapter without MK2 nodes OR a part which fits into the slots and makes the adapter look sleek

- make J & K tanks radially attachable

- move the J aerodynamic tail and J engine mount to the tanks or aerodynamics tab

- add a K tank without a hollow inside

- add a K aerodynamic tail

- add more wings

The above is very likely to be added others probably not

These parts seem way too OP.

The Scramjets seem the most OP of all. They can provide like 1,500kN of thrust for those tiny little 2.5ton things. In FAR, at least.

Stock parts definitely lack a scram jet and such, and it's nice to have something better than the turbofan, and better than rapier without having to run on ox, but it's too good. It gives like double the thrust that it should.

Yeah they are probably going to stay OP for now until i figure out a better way to implement them. Because to be honest, id like my space planes to still have enough delta v to do things once is in orbit, i find building large SSTO with non-op engines, its really hard to have fuel left to actually do things once its in orbit. (without spamming intakes and use wing parts everywhere)

One way im thinking of how to implement such an engine is to have some sort of single mode LFO jet engine with a converter thats able to constantly convert intake air into oxidizer. Once the converter doesnt provide enough oxidizer, it will start consume onboard oxidizer accordingly.

Ideal performance would be something like: uses LF only below 20km with isp=2000-3000 speed up to mach2, uses little or medium amount of oxidizer to keep up the combustion at 20km-30km with isp=1000-2000 speed up to mach 4-5. Finally, it uses normal ratio (1.1:0.9) at 30km-40km with isp=500-1000 speed upto mach 7. And it shuts off at 40km.

If you know such engine has already being designed or proposed let me know!

These new parts a looking great! Just what I wanted from a larger cargo capacity bay!. Btw, is the new JX(tended ) profile similar to what you showed earlier when concepting it? I'm trying to judge whether it would fit 3.5m parts. Also if that's a flat bottom I'm seeing then this profile is asking for a rear cargo ramp for driving rovers in and out!

A cargo tail probably will be added for it, but it doesn't fit 3.5m parts...

I really want to ask: why does everyone likes cargo bays fits 3.5m parts? i know MFS have vehicle parts that needs 3.5m clearance, but if you want to make it works well you really need at least 4mx4m cargo bay which only mk4 parts can do.

Anyway im currently at the process of remodelling the K parts, should i give it a bulge to fit 3.5m parts? (like on the left) or keep it the way it is (right)

[ZodiusInfuser]

I really want to ask: why does everyone likes cargo bays fits 3.5m parts? i know MFS have vehicle parts that needs 3.5m clearance, but if you want to make it works well you really need at least 4mx4m cargo bay which only mk4 parts can do.

I was curious more than anything, as I couldn't tell if the part was symmetric/asymetric or whether its large curve was larger than 3.5m or exactly 3.5m (for some planned 3.5m adapter maybe? ). Could you show a front on view of the profile?

I haven't got a particular use case in mind for a plane capable of transporting 3.5m parts. There are a few space station parts from Nertea that are 3.5m that a large bay could potentially be of benefit for (http://imgur.com/a/k6qrA#3). As for the MK4 parts, they look great but are not sleek enough for my liking.

Anyway im currently at the process of remodelling the K parts, should i give it a bulge to fit 3.5m parts? (like on the left) or keep it the way it is (right)

http://i.imgur.com/8yCSGUE.png

Perhaps if the bulge was centralised rather than just on the top side? The original does look nicer though, and as you show fits in well with the existing J profile. Maybe have a K-XWB profile that is just bays?

[Balto-the-Wolf-Dog]

I actually like the bulge, it gives it some dimension and shape. If that weren't done I'd still like to see some irregularity along the longitudinal axis. Maybe a pair of ridges or something instead of a central hump. Just something to give it some lines.

[stali79]

yeah keep the bulge! and keep the parts hollow if possible, I loved the 1.7 hollow bay like parts.

[innociv]

It'd be possible to make an SSTO that would get to LKO with thousands of dV to spare if the scramjet just provided far less stationary thrust. Could still do a turbojet or 2, plus 1scramjet, plus an LV-N or 2.

Or make it require some extra 2ton part similar to a precooler that gives the scramjet more thrust when stationary after nerfing it, can work too.

Right now you can pretty much leave Kerbin entirely with the scramjet alone. http://images.akamai.steamusercontent.com/ugc/630854724290007916/3E220CCC0088EAEFF0BEFCB6119E5B14B50B8B9A/ This was my first experiment with them and could do a lot better. That's with no rocket at all, just 2 scramjets.

Not saying make them useless, as I agree with you (in 1.0+ it's near impossible to get a SSTO to LKO with some decent dV left over), but they take out any challenge at all right now.

As far as the 3.5m cargo bays, there's Tweakscale for that. I like the geometry of the current bays. In general I like parts that match up with stock ones.

Edited August 13, 2015 by innociv

[gilflo]

Your Opt J 61 turboramjet is fantastic. I use it with 2 Rapier and 4 nukes to send my mk2 cargo to orbit and i don't need to use the Rapier closed cycle. My cargo is more than 100T. I use Kerbokatz afterburner at take off on OPT J61 and Rapier, then cut afterburner when mach>1.5 at 12km. I only use fuel, cut Rapier at 24km, start nukes, cut OPT at 40km, then when i am establish on my 100km orbit I got 70% fuel left! My oxy reserve is just needed for small help from RCS vernor control when landing on low gravity planet with nukes as they don't have gimbal and for the same reason for take off or if i use RAPIER for take off rotation. 2 shock cone intakes per engines leave them alive to give thrust until 40km, provided you reach mach 5 or more for climb. I use intake build air mod manually to distribute air intakes between engines. The automatic distribution with this mod is not satisfactory with OPT ramjet, i don't why, it's working fine with all other engines, even Rapier, but it looks like it's forgetting OPT J61.

I dont still use your cargo part because because i have not built stuff bigger than a 7t scansat satellite to send in orbit.

Here is my starblaster cargo with OPT RAMJET and also in my KerbalX

http://forum.kerbalspaceprogram.com/threads/131211-Starblaster-Cargo

Edited August 13, 2015 by gilflo

[sashan]

Your Opt J 61 turboramjet is fantastic. I use it with 2 Rapier and 4 nukes to send my mk2 cargo to orbit and i don't need to use the Rapier closed cycle.

Closed cycle is oxidiser-burning, right? Maybe you would be better off using Turojets then? They ar emucm more powerful.

[gilflo]

Yes you're right. I did not try. That's an option. But i am not sure i can use them until 24km.

[innociv]

Closed cycle is oxidiser-burning, right? Maybe you would be better off using Turojets then? They ar emucm more powerful.

It's pointless to use rapiers or turbojets with the turboramjet, currently. The turboramjet is better than them both, just add in a rocket for out of atmosphere.

You can get to Mach 7.5 easily with the turboramjet in FAR at least. That easily gets you out of the atmosphere and you just need a rocket from there.

[sashan]

Turboramjet is simply OP. IMO it should be nerfed at low altitudes.