Three Stock 3.75m Catalogue Enhancements

[Bomoo]

Two things come to mind immediately when I'm trying to work with the (relatively) new 3.75m stock parts. The first two are both things that KW Rocketry already does, but I feel they would be a simple and highly useful addition to the stock catalogue.

(1) Low-profile Sloped 3.75/2.5 Adapter

Yes, you heard me, a low profile sloped 3.75m-to-2.5m adapter analogous to the Rockomax Brand Adapter 02 and FL-A5 Adapter.

(2) Kerbodyne ADTP-2-3 Should Hold Fuel

There's not really an excuse as to why this thing can't hold fuel. It's a mere .cfg edit, and users who want a plain structural part with no fuel can simply dump it using tweakables. Heck, I'd make this edit myself if I wasn't so damned lazy.

(3) Quarter/Half Radially-attached Structural Mount

The heck do I mean by that? Well, get your eyeballs a load of THIS. Essentially what I mean is a quarter or half-circle structural piece that attaches to 2.5m diameter parts and creates a raised 3.75m diameter surface for attaching junk like RCS blocks or solar arrays to. I can get the same effect, as you can see, through clipping shenanigans, but I'd prefer not to tempt the kraken. Make it easier for folks to build Copernicus-style interstellar craft, why not. And it's something that, to the best of my knowledge, no mod does!

[Jouni]

(2) Kerbodyne ADTP-2-3 Should Hold Fuel

There's not really an excuse as to why this thing can't hold fuel. It's a mere .cfg edit, and users who want a plain structural part with no fuel can simply dump it using tweakables. Heck, I'd make this edit myself if I wasn't so damned lazy.

The adapter used as a fuel tank should be a different from the purely structural adapter. In the future, we'll probably get the ability to move kerbals from one part of the ship to another without EVA. Then it'll be reasonable to assume that kerbals can move through empty structural parts, but not through fuel tanks, even when they're empty.

[Sky_walker]

Please, please, please add an 3.5m equivalent of the Poodle.

Basically: a flat engine that can be fit in-line into the rockets. Right now we have just one in-line engine for the largest size: Kerbodyne KR-2L Advanced Engine, and it's so enormous that it very much limits the designs we can do, and sadly: stock fairings around engines don't allow us to put Poodle in between 2 XL-sized tanks without looking whacky and completely out of place.

You know what would be great to have too?

In-line Clamp-O-Tron Sr. build on 3.5m (XL) part.

Docking bay based on a Kerbodyne S3-14400 Tank with hatches opening space-shuttle-style and a Clamp-O-Tron Docking Port at the one end of interior.

But I would swap any of these two for an XL version of Poodle.

The adapter used as a fuel tank should be a different from the purely structural adapter. In the future, we'll probably get the ability to move kerbals from one part of the ship to another without EVA. Then it'll be reasonable to assume that kerbals can move through empty structural parts, but not through fuel tanks, even when they're empty.

So far Kerbals cannot move between the components so there's no reason I would see why adapters cannot hold fuel - especially as enormous adapters as this one. If someone wants to use it as a purely structural element - he is free to remove the fuel using tweakables, if such fuel would ever be added in.

And IMHO it should - it would differentiate between low-profile adapters and a full-size adapters. Give them a value in game other than ascetics.

[CaptRobau]

The adapter used as a fuel tank should be a different from the purely structural adapter. In the future, we'll probably get the ability to move kerbals from one part of the ship to another without EVA. Then it'll be reasonable to assume that kerbals can move through empty structural parts, but not through fuel tanks, even when they're empty.

That would be a very bad design decision. It would make station construction very awkward, as it would make propulsion placement very unintuitive (radial with a lot of fuel-lines). Real-life stations have had transfer tubes through fuel tanks, from Skylab to Mir. Squad could make a bunch of transferable fuel tanks and adapter, but that would just increase part bloat and would add nothing but extra work for something which could be dealt with through a bit of hand-waving.

[Jouni]

That would be a very bad design decision. It would make station construction very awkward, as it would make propulsion placement very unintuitive (radial with a lot of fuel-lines). Real-life stations have had transfer tubes through fuel tanks, from Skylab to Mir. Squad could make a bunch of transferable fuel tanks and adapter, but that would just increase part bloat and would add nothing but extra work for something which could be dealt with through a bit of hand-waving.

The current ADTP-2-3 weights 0.2 tonnes. Based on its mass, its fuel capacity would be 320 units – a bit less than the FL-T400 fuel tank.

On the other hand, the adapter is a really big part. Its diameter is 2.5 m to 3.75 m, and it's a bit taller than the FL-T400 (or the X200-16 or the S3-3600). Based on its dimensions, its fuel capacity would be around 3200 units, increasing the dry mass to 2 tonnes. This makes the empty fuel tank way too heavy to be used as a structural part.

Maybe we could add a passage tube to the fuel tank. As kerbals apparently require 1.25 m parts to pass through, the tube would reduce the fuel capacity by around 500 units. The dry mass would probably not decrease correspondingly, as we're adding new internal structures to the part. Therefore we would have a slightly inefficient fuel tank with mass fraction 1/7.75 instead of the usual 1/9, but it should still be useful for launch stages.

[Red Iron Crown]

A 3.75m reaction wheel, stack separator, docking port and battery would round out the lineup, in addition to the parts mentioned above.

[Capt Snuggler]

The current ADTP-2-3 weights 0.2 tonnes. Based on its mass, its fuel capacity would be 320 units – a bit less than the FL-T400 fuel tank.

On the other hand, the adapter is a really big part. Its diameter is 2.5 m to 3.75 m, and it's a bit taller than the FL-T400 (or the X200-16 or the S3-3600). Based on its dimensions, its fuel capacity would be around 3200 units, increasing the dry mass to 2 tonnes. This makes the empty fuel tank way too heavy to be used as a structural part.

Maybe we could add a passage tube to the fuel tank. As kerbals apparently require 1.25 m parts to pass through, the tube would reduce the fuel capacity by around 500 units. The dry mass would probably not decrease correspondingly, as we're adding new internal structures to the part. Therefore we would have a slightly inefficient fuel tank with mass fraction 1/7.75 instead of the usual 1/9, but it should still be useful for launch stages.

maybe crew tunnels could be a tweakable on a fuel tanks/parts? and would increase the dry mass of a tank, but a reduction in capacity? externally it would only require the addition of a small 1m texture.

[Bomoo]

Please, please, please add an 3.5m equivalent of the Poodle.

Basically: a flat engine that can be fit in-line into the rockets. Right now we have just one in-line engine for the largest size: Kerbodyne KR-2L Advanced Engine, and it's so enormous that it very much limits the designs we can do, and sadly: stock fairings around engines don't allow us to put Poodle in between 2 XL-sized tanks without looking whacky and completely out of place.

Oh yes, I forgot to mention this, but this is another of my missing features. Perhaps something like a Centaur (double Skippers!) or/and a slightly slimmer Saturn V third stage "J-2" engine (or quad Poodles??). The Kerbodyne KR-2L strikes me more of as an Ariane 5 main engine analogue than a viable upper stage or even deep space solution.

Edit: In the meantime, here's what I managed to bodge together for a 3.75 upper stage solution. The fairing you see is the excellent KWR 5m-3.75m interstage shroud.

maybe crew tunnels could be a tweakable on a fuel tanks/parts? and would increase the dry mass of a tank, but a reduction in capacity? externally it would only require the addition of a small 1m texture.

Excellent solution, and a medal for you, good sir. They might create a repeatable external tube skin texture, two 1.25m end cap textures, and design each part so that it creates a 3d cylinder model through itself, and caps it with two of the 1.25m caps if they wanted to get fancy. Further, I don't see why an unpressurized structural part would be any more habitable than a fuel tank, at least for unsuited kerbals. And even suited I'd argue the part really isn't made to be traversed by kerbonauts, i.e. "anthropometric" as the Russians would put it (would that be kerbometric in our case?). A tweakable crew tunnel option, however, solves both sides of the question beautifully.

Edited July 24, 2014 by Bomoo

[Majorjim!]

maybe crew tunnels could be a tweakable on a fuel tanks/parts? and would increase the dry mass of a tank, but a reduction in capacity? externally it would only require the addition of a small 1m texture.

When they implement crew transfers it will be like

Fuel transfer now, as long as they are connected

The crew can be moved. It's simpler that way.

[Whirligig Girl]

the adapter's model is hollow. It can't have fuel in it without a new model.

[Sky_walker]

Oh yes, I forgot to mention this, but this is another of my missing features. Perhaps something like a Centaur (double Skippers!) or/and a slightly slimmer Saturn V third stage "J-2" engine (or quad Poodles??). The Kerbodyne KR-2L strikes me more of as an Ariane 5 main engine analogue than a viable upper stage or even deep space solution.

Edit: In the meantime, here's what I managed to bodge together for a 3.75 upper stage solution. The fairing you see is the excellent KWR 5m-3.75m interstage shroud.

Yea, but these hacks-around don't come with any nice white fairing that would fit the rocket design. :/

But yea - be it 1, 2 or 4 engines - doesn't matter as long as we get something for an XL-sized upper stages

BTW: Good point about Kerbodyne KR-2L working as an Ariane 5 main engine - that's exactly how I use it. In my version of the Ariane 5

the adapter's model is hollow. It can't have fuel in it without a new model.

Model got nothing to deal with it. It's just a change to the part in a configuration.