Engines won't ignite even although all conditions are met.

[Vaporized Steel]

I'm building a very complicated Eve landing design. A rocket carrying a behemoth to and from eves surface that has the ability to glide once it reenters the atmosphere for a precision landing, shed it's wings and fairings and lands because i wan't to navigate to eves 7500m peak. It does this, I tested it, and I'm very happy with it. The craft is pure stock.

This is it.

It has 3 inflatable heatshields. The craft cannot turn once it has reentered the atmosphere to shed the inflatable heatshields, because it will get out of control when I do. It has to maintain it's nose in the direction of the prograde marker during descend, and recovering in flight will take to much time and cause me to lose altitude and I'll not be able to glide far enough. So the heatshield must be jetissoned and safely removed while facing prograde.
This is a problem, but not impossible to solve. All 3 heatshields have engines attached to them. Although you can only see the skipper engines on the 2 outer shields. The central has one to underneath.
I'm not sure if they produce enough power to actually shed, but if not I'll upgrade to mainsails or even vectors if that proves necessary. Each engine is attached to a small fuel tank.

In the picture I have already staged the outer shields, they're floating now. Stage "14" is the center heatshield decoupler and the engine attached to it, also having a engine with a fuel duct ensuring it get's it's requirements met. When I stage that one it will float away, just like the other 2 outer heatshields. The engines do not ignite.
As you can see my throttle is put at full power.
Can anybody tell me why the engines do not light?
Is this a bug? In any case, this should work or I have some big redesigning to do.

[Jarin]

I don't see a fuel bar by the engine. Looks like the staging is borked. Right-click engine and see if you can activate it.

[Vaporized Steel]

Yes I can! It does light. Now when it is lid and I stage it it quits completely
LOOOL, What the heck is going on here.
I used solid rocket motors in my 1st test flight. But they werent powerfull enough, they did maintain power once jettisoned. Sadly they're to weak to use them to fight the air during re-entry.

Edited June 21, 2016 by Vaporized Steel

[bewing]

I don't think the engines will run without a probe core on each of them to keep them turned on. And I think you will need the core's SAS function anyway to keep the IHS's from smashing into your ship -- the engines will provide enough electricity to keep the core running, of course.

(And that's amazing that you can manage to keep those wax-and-feather wings protected on a high speed reentry!)

 

Edited June 21, 2016 by bewing

[Vaporized Steel]

Good thinking.

I didnt thought that was necessary, to install a probe core. Im not at home now and ill test when I get back home.

If it is required then I think it shouldnt. My knowledge is that when a engine is lid, well, it's lid. No computer needed to maintain its thrust if the tanks are pressurized. I know fuel is pumped electrically, but in a pressure tank they shouldnt just stop, right.

(Correct me if im wrong. Im just a gamer.)

 

Maybe its a good idea for squad to remove that requirements. The main vessels probe core should be able to ignite them.

As for the waxing of the wings, it doesn't. Lots of testing and properly placed struts make sure it does not. But yeah, it required lots of testing and editing. The engines are moved with the toolset slightly of the heatshields center. Causing it to flip in the wind. The idea is not to make them fly away. Just set the right amount of thrust and fuel to make them get out of the way far enough to prevent a collision.

That said I dont think the probe cores reaction wheels have any effect at 500m/s with a 10m umbrella attached to it.

Edited June 21, 2016 by Vaporized Steel

[swjr-swis]

Not a bug, or at least it's 'working as intended', even if very annoyingly so. Missing probe cores is the issue.

The skippers do light up, but as soon as they detach, since the game deems them 'not controllable', the game automatically zeroes the throttle again - a very annoying and contradictory behaviour since supposedly they cannot be controlled, so how is the throttle being changed. More appropriately, the throttle should simply be left as is, in this case, full out, and the engines should keep firing.

Solid boosters do keep firing without a core, because they cannot be throttled once lit up, so they will merrily continue to use up their fuel, core or not.

[Vaporized Steel]

I'm at home and have indeed confirmed it's the lack of probe cores. This annoys me, but yeah it's fixed now. Still have to test whether it works during re-entry, I'll confirm when it does since I shared my craft I think I should. The reason it annoys me is I want limited part count on any vessel as complicated as this..

@swjr-swis

Your story about SRB's is true. They cannot shut down so it doesn't matter what the game deems to be uncontrollable, they'll keep firing.
But that is the thing about the difference between SRBs and LF engines. The SRB's cannot be throttled, and LF engines can.

I think the game says, you are no vessel anymore, then there is no throttle input to speak off, meaning automatic engine shutoff. It probably does the same for SRBs. But since SRB's aren't throttle controlled they don't suffer that consequence. Multiple SRB's might work, but that also doesn't contribute to part count. So maybe a very high TWR low profile SRB motor like a OP Flea solid motor might be in order.
Like I said, I don't think a computer probe is needed to maintain engine fire, but if that is a actual requirements in real life rocketry, I give in and accept this reality.

It probably isn't a requirement in rocketry, so it should keep firing, but the game mechanics are preventing it causing the anomaly like you said.
If it isn't to much of a workaround I would like Squad to change this game mechanic, allowing a lid liquid fuel engine to keep firing as a probeless and thus uncontrollable vessel. Throttling is a electrical requirement, so being probe less and without electricity shouldn't even change your throttle. It's not even annoying, but unrealistic. No matter how scarce this appliance is required in vessel building.
This saves me the part count of having to add a probe core. Once released the probe less object should just be "debris" like it is considered now but maintain any persisting command giving prior from detachment until that command ends (like a engine firing, or any thing else for that matter) although I can't yet name them.

Edited June 21, 2016 by Vaporized Steel

[Speadge]

its not the "u are no vessel", but "you are not contralable - therefore we shut down engines to not waste fuel".

Think about a probe that is doing a burn without alternator in the shadow... it might run out of EC, starts spinning and wastes all fuesl, cause it had 100% throttle when it got to 0 EC... so ur mission would be over.
Instead, it stops firing for saving fuel until u can start a new burn when it recharged.

[Vaporized Steel]

You sure it's "you are not controlable"?
This means a probe with a probe core quits his engine when it has no EC left. Does this mean that in my design I could use batteries instead of a probe core, and it's not related to having a probe but something with EC.

I doubt your right but I'll test it out soon and I'll see. but if you are right then it's the alertness of the pilot in question to make sure he quits his engine in the shadow close to 0 EC. What your trying to say indicated pilot error.
Either you make sure you have enough electricity in the shadow, or you make sure you shut off your systems before your close to 0EC.

I'm not sure why I have to suffer from a unrealistic game mechanic just to serve the stupidity of pilot error for anyone forgetting to shut off his/her engine when reaching 0 EC.
Ofcourse it being unrealistic is assuming you need a computer to keep a engine lid, but that sounds so unrealistic that I'm sure it's bogus.

Edited June 21, 2016 by Vaporized Steel

[Vaporized Steel]

Atleast the design works now.

Haven't yet finished the jetisson system for the centre heatshield. Because it stayed attached I couldn't pull the nose up. But it should have very good gliding distance. I might share the complete mission once completed when I get every system to work properly, but that will take some time.

The craft is intended for aerobraking at eve, yet I don't have a requirements that I want the craft to aerocapture at eve at interplanetary velocities. First of all, that's hard or near impossible with any craft, so I will use some LVNs to slow down for aerobraking. "Bewing" mentioned how well I protected the wings. Well, it should. But as you can see in on the pictures via the imgur link below the wings are the only parts on the ship that seem to overheat. There are 2 main wings on each side (4 total) thus 4 overheat bars visible. Just in case you thought there were only 2 wing parts 1 on each side.

I am absolutely positive that the heatshield covers the full width area of the vessel. Including the height radius so either those big wings work as radiators and I have nothing to worry or I am confused. The very wing tips are protected by the heatshields. They still seem to capture alot of heat. It went OK within reasonable limits, it might not do the same for eve. And this is my first aerobraking design for the ship and I always test on Kerbin first before moving on to testing at the target destination.

Atleast I have proof of concept for aerobraking stability.
If anybody can help guess why those wings catch heat I'm glad to hear. Would radiators help without braking off if placed directly behind the heatshield during re-entry. Ofcourse it's my design but there are many appliances to think off so if somebody can help me nail it down I know what to look for.

Full Album

 

Edited June 21, 2016 by Vaporized Steel

[Signo]

I think that the FAT wings will explode around 45000m on Eve while you are re entering. They do not have enough heat tolerance (max 1200° if I remember correctly). It is hard to save them re entering on Kerbin from LKO.

You should try with Big-S parts.

[Vaporized Steel]

Hmm............ cry...!

These wings look so nice on this particular craft. The BIG-S will definitely look less eye catching. But it probably is realistic, since the FAT wings are aircraft wings, not spaceplane wings. I didn't considered this, but luckily it will only require readding and balancing more heat resistant wings like the BIG S ones. Any chance from a purely theoretical standpoint that static radiator panels will absorb the heat. Any theoretical system i can implement in the VAB/SPH whereby radiator panels only draw heat away from those wing parts and ignore the other parts? Do radiators even know they have to radiate below 1200c for the less heat resisting parts on the ship, assuming you have plenty enough.

Edited June 21, 2016 by Vaporized Steel

[Speadge]

1 hour ago, Vaporized Steel said:

Does this mean that in my design I could use batteries instead of a probe core, and it's not related to having a probe but something with EC.
 

with just bats and no core its still not controable
So yes, im sure its "you are not controlable". And yes - a probe without EC cuts its engines.

Edited June 21, 2016 by Speadge

[Vaporized Steel]

Ok haha, got it. A probe core serves controlability and EC obviously, should have figured that. It's controllable now :=)

[Jarin]

12 hours ago, Speadge said:

Think about a probe that is doing a burn without alternator in the shadow... it might run out of EC, starts spinning and wastes all fuesl, cause it had 100% throttle when it got to 0 EC... so ur mission would be over.
Instead, it stops firing for saving fuel until u can start a new burn when it recharged.

The annoying part here is that the engine won't shut down in your example. The probe core is still there, so the engine keeps firing.

[Speadge]

it shuts down at 0EC, IIRC