Allow heat shields to inflate when the top node is in use

[KerikBalm]

So I was designing an interplanetary vehicle with an inflatable heat shield for aerobraking at kerbin.. but I also wanted a docking port at that end of the ship... no problem... stick a shielded docking port at the top node (its pretty heat resistant too)... only to find out that the inflatable heat shield is now useless and cannot deploy with the top node taken... my question is.... WHY?!

I worked up a solution making use of surface attach, the offset tool, and two structural girders... but I suggest we remove this gameplay restriction, because I don't see its purpose.

[solarbearman]

I don't think this will work

What about the shroud?

[KerikBalm]

well, I had the shroud disabled, the inflatable was basically a nose cone, with just a shielded docking port on top. A shroud looked stupid in such a scenario.

Allow it to inflate whenever the shroud is not present?

[Snark]

 This topic has come up before, and the answer is that it's not an oversight.  It's a very deliberate design feature.

In short:  the shield has been deliberately designed not to allow you to do what you're trying to do, precisely because people would want to do that and Squad considered that to be unrealistic and overpowered.  The idea is that the shield is just a floppy canvas bag, so you really can't mount anything on it.  When the shroud is in place, you can mount stuff to that ... but the presence of the shroud also precludes inflation.

If you really want to do this, you have to put a decoupler on top of the heat shield's pointy end so that you can blow off whatever's attached before you inflate it.

In short:  they did it on purpose, it's not going to change.

[danfarnsy]

23 minutes ago, Snark said:

Squad considered that to be unrealistic

Snark, you just made my day.

[KerikBalm]

2 hours ago, Snark said:

 This topic has come up before, and the answer is that it's not an oversight.  It's a very deliberate design feature.

In short:  the shield has been deliberately designed not to allow you to do what you're trying to do, precisely because people would want to do that and Squad considered that to be unrealistic and overpowered.  The idea is that the shield is just a floppy canvas bag, so you really can't mount anything on it.  When the shroud is in place, you can mount stuff to that ... but the presence of the shroud also precludes inflation.

If you really want to do this, you have to put a decoupler on top of the heat shield's pointy end so that you can blow off whatever's attached before you inflate it.

In short:  they did it on purpose, it's not going to change.

Well, It can be worked around with the offset tool, or modded away, I did 1, and then #2

Its not so hard to believe that there was a rigid internal structure at the core to mount things too. Think of rigid airships... or even better, blimps which have their envelope supported by pressure, but a few "hardpoints" for mounting engines, crew compartment, control surfaces, etc.

Inflatable doesn't mean nothing can be mounted to it if a hardpoint is specifically designed

I don't think its unrealistic to have a 1.25m connection at the top... just imagine a rigid girder section going through the center, and then the stuff around that inflates. It even looks like its a collection of symetrical "petals" around a core...  all I'm saying is that the core should be strong enough to attach a docking port.

Even worse is that you can expand the heat shield in the editor, and then place something on the node... although its quite hard to launch such a thing... you'd think that at least in the editor you could expand/retract it. If nothing is meant to be allowed to attach to the top node while inflated... then perhaps the top node should be removed when expanded... just as a shielded docking port has no top node (other suggestion: give the shielded docking port a node to use in the editor when the shield is open and the docking port is extended)

[Snark]

3 hours ago, KerikBalm said:

Its not so hard to believe that there was a rigid internal structure at the core to mount things too. Think of rigid airships... or even better, blimps which have their envelope supported by pressure, but a few "hardpoints" for mounting engines, crew compartment, control surfaces, etc.

Inflatable doesn't mean nothing can be mounted to it if a hardpoint is specifically designed

I don't think its unrealistic to have a 1.25m connection at the top... just imagine a rigid girder section going through the center, and then the stuff around that inflates. It even looks like its a collection of symetrical "petals" around a core...  all I'm saying is that the core should be strong enough to attach a docking port.

Oh, just to be clear, I'm not saying I disagree with you-- my post wasn't "I believe all these things," it was "this is my understanding of the designer's explicitly stated intent".

In other words, I wasn't saying that the idea is a bad one, just that it's one that I'm pretty sure is going directly against what the designers deliberately decided (and are unlikely to change minds about).

[KerikBalm]

well, thats fine, as the devs made the game easy to mod from the outset... that should be standard practice in the games of today.

I've already modded it, and I don't feel bad at all about it. I am keeping the limitation that it can't be retracted and deployed at will though, as I think it makes for an interesting gameplay limitation/choice. The lack of another useable node on top for something that won't be staged, imo, was too limiting though.

 

This is all I ask for:

 

Edited May 16, 2016 by KerikBalm

[MacLuky]

how did you mod that?

[Firemetal]

19 hours ago, MacLuky said:

how did you mod that?

He did it in the VAB mate.

Personally, I have no problems with the inflatable heat shield. I believe there should be a 1.25m/5m inflatable heat shield.I had the idea of adding an inflatable heat shield that can be docked to the front or back of the ship, used and ditched. Would be awesome for a Jool V mothership.

Still I don't see how that is unrealistic. The shield should be able to inflate with something on top of it. But I respect Squad's decision and I doubt they will change it in the future.

[Wyzard]

How are the kerbals supposed to access that docking port?  Cut a hole in the heat shield?

[Wjolcz]

Into the atmosphere docking port-first? That doesn't sound right.

Dunno about the inflatable heat shield, but maybe a new part could be introduced to get around this. Like a ballute, or something.

[razark]

7 hours ago, Wyzard said:

How are the kerbals supposed to access that docking port?  Cut a hole in the heat shield?

7 hours ago, Veeltch said:

Into the atmosphere docking port-first? That doesn't sound right.

A rigid core structure, surrounded by the inflatable structure.  As long as you are willing to accept that the shielded docking port is at least as capable as the inflatable structure at resisting heat, then it's perfectly sensible.

Edited August 22, 2016 by razark

[KerikBalm]

On 8/19/2016 at 7:14 PM, MacLuky said:

how did you mod that?

I think I went into the config and changed "        allowAnimationWhileShielded = False" to "        allowAnimationWhileShielded = True" - but I did that mod on my older computer, and on my newer computer the inflatable heat shield is stock (for now)

7 hours ago, Veeltch said:

Into the atmosphere docking port-first? That doesn't sound right.

It is the *shielded* docking port, which is quite resistant. When I was testing this combo, there were cases where the shielded docking port wasn't resistant enough, but I go docking port first into the atmo quite frequently with my SSTOs

[Snark]

15 hours ago, Veeltch said:

Into the atmosphere docking port-first? That doesn't sound right.

Aside from the docking port being very heat-resistant, as @KerikBalm points out... there are also plenty of uses for the inflatable heat shield that work great even if the shield is on the back side of the craft, i.e. trailing behind you like a very very heat-resistant parachute.

In fact, it's often simpler to engineer a craft that way, since the high drag on the inflatable tends to make the ship want to flip to that orientation anyway.  Kind of an "if you can't beat 'em, join 'em" approach to engineering. 

[KerikBalm]

Yea... I tried to keep my craft like this as long as possible:

But it just wouldn't stay, and the fairing was barely heat resistant enough (stuff near the fairing base could overheat, took a few tries to get it right

Drogue chute?

Yep, its a drogue chute

A pretty good drogue chute, the main chutes were ready to go, no need for the radial drogues (which I had on there anyway)

[Snark]

My designs using the inflatable shield often don't even bother trying to stay inflatable-prograde.  They just enter the atmosphere with the inflatable trailing behind from the get-go.

For very high-speed entries where that would cause something to go boom, I make my craft fit in a reasonably compact "footprint" and stick a 2.5m shield on the prograde side of the ship.  That is, it's leading with the 2.5m heat shield, with the big inflatable trailing.

But the above is only for really high-speed reentries.  If I'm not going too fast, I often don't even bother with the 2.5m heat shield at all-- just lead with naked engines.  Engines are fairly heat-resistant, and my experience is that the drag from the big (trailing) inflatable will generally muscle the trajectory to be slow enough, soon enough, that the engines don't go kaboom.

Another approach is to just put an inflatable at both ends of the ship, then you get the best of both worlds and it's steady as a rock in whichever orientation you prefer.  Here's an example:

Fuel tanker, bringing back a load of fuel from the Mun.  It's built around a single giant tank from SpaceY.

It's rock-solid stable during aerobraking, since its center of mass is slightly forward of center, and the drag from the inflatable on the back balances out the drag from the inflatable in the front.

Plowing almost 400 tons behind a 10-meter heat shield at lunar-reentry speed through air at 28 km gave me the longest F12 aero-overlay drag arrow I've ever seen. 

[magnemoe]

 

1 hour ago, Snark said:

My designs using the inflatable shield often don't even bother trying to stay inflatable-prograde.  They just enter the atmosphere with the inflatable trailing behind from the get-go.

For very high-speed entries where that would cause something to go boom, I make my craft fit in a reasonably compact "footprint" and stick a 2.5m shield on the prograde side of the ship.  That is, it's leading with the 2.5m heat shield, with the big inflatable trailing.

But the above is only for really high-speed reentries.  If I'm not going too fast, I often don't even bother with the 2.5m heat shield at all-- just lead with naked engines.  Engines are fairly heat-resistant, and my experience is that the drag from the big (trailing) inflatable will generally muscle the trajectory to be slow enough, soon enough, that the engines don't go kaboom.

Another approach is to just put an inflatable at both ends of the ship, then you get the best of both worlds and it's steady as a rock in whichever orientation you prefer.  Here's an example:

Fuel tanker, bringing back a load of fuel from the Mun.  It's built around a single giant tank from SpaceY.

It's rock-solid stable during aerobraking, since its center of mass is slightly forward of center, and the drag from the inflatable on the back balances out the drag from the inflatable in the front.

Plowing almost 400 tons behind a 10-meter heat shield at lunar-reentry speed through air at 28 km gave me the longest F12 aero-overlay drag arrow I've ever seen. 

Nice and good capacity, you can however not land this. You could dock the bottom shield and left it in Minmus orbit and pick it up afterward. 
What the 1.25 meter radial tanks with no engine for?

Have two designs with front mounted inflatable, an tanker and a 20 kerbal liner, the tanker return from Minmus, the liner from just outside Kerbin SOI, it also return fast as in 8-10 days from the SOI, no problem with it, as long as craft is balanced, landing is another issue as you get far more g forces, remember worked a lot to get the eve lander to work, Landing on Eve is hard in any cases. 

[Snark]

5 hours ago, magnemoe said:

Nice and good capacity, you can however not land this.

Well, of course I can't land it.  Why on earth would I want to land it?  The whole point of this particular ship is to get fuel from the Mun and move it to LKO where it's useful.  If I landed it... I might as well just launch directly from KSC.    The purpose of this ship is to aerobrake to orbit.

For cases where I need to actually land the thing with the heat shield on it, I just decouple the shield at the appropriate point of the descent.

5 hours ago, magnemoe said:

What the 1.25 meter radial tanks with no engine for?

More fuel for the LV-N's.  They're plumbed in with fuel ducts.  All of those 1.25m radial tanks are LF-only tanks.

[StrandedonEarth]

We're getting sort of off-topic from the OP, but here's one vehicle (Space Camp Bus) that stays nicely inflatable-prograde. All that heavy landing gear helps, as do the air brakes, but the real key is that the Mk3-2.5m adapter-tank nearest to the heatshield is full, while the other one is empty, helping keep the CoM ahead of the CoD.