ISRU kills velocity if active during takeoff...?!(And heat issue)

[Arugela]

I have a vehicle that will be part of an asteroid collecting kit and will itself be a lander for a mothership. I was doing calculations and found that the 1500 ore it can carry will get a little more deltaV if left full on launch then used at some point during transit. Next thought comes along and I figured the earlier I spend the fuel, aka on takeoff, the more efficient it will be and the more deltaV it is adding to my overall trip. So I go about mining and fueling my vessel on the runway, as this is innitially empty to be hauled inside another vehicle and is saves me a lot of carrying weight and I take off. I then notice something. If the ISRU is converting materials at all the velocity drops to 0m/s. I originally took off, got to about 80m/s, but then the velocity drops to 0m/s and I reland on the launchpad for some mysterious reason. I sit there a second thinking about what is going on and notice that the ore is dropping. This led to the obvious conclusion. The ISRU turns on when it has the chance again and does not actually shutoff fully when it runs out of resources.. So I turn it off manually via my shortcut and the ship magically starts going in the air again. This leads me to why I'm here. I actually want to use the ISRU during takeoff to use up the ore as early in the flight as possible. But, as mentioned it for some weird reason kills my vessels velocity in flight... Is this supposed to happen? And if so does anyone know why it does. Why would the ISRU have any affect on my velocity during flight?!

BTW, pardon the overheating engines. I just removed 4 twin boar engines and replaced them with orange tanks to give it more deltaV. I have not yet dealt with the overheating when you to around 900m/s from the lower TWR.

Craft if anyone is interesting in testing:

http://www./download/fpw47zn3i4xszfa/The_Orion_Retriever_Lite.craft

Vehicle after fueling up on the launchpad: (if you want to fuel this vehicle in a sane manner. Use 4x engineers in the crew compartment.)

Edited October 30, 2015 by Arugela

[Guest]

There might be an issue with fuel density. I know that they're not balanced equations.

[Arugela]

It flies with the ore tank full and empty. What does the fuel density do? it seems this problem occurs the moment you are flying and you turn on the ISRU converter.

[Snark]

I've never had any problems with that, I run the ISRU while launching just fine.

With one caveat: the ISRU doesn't fill tanks symmetrically. It seems to pick one tank, fill that one up completely, then move on to the next tank, etc.

So if (for example) I have a pair of radially-attached fuel tanks, it'll fill up the left one before it goes after the right. Not a problem if I'm sitting on the surface refining until I'm full before takeoff. But if I'm running the ISRU while flying, I end up with an asymmetric mass distribution that makes it hard to control the ship, and I have to try to manually balance them. Wish they'd fix that.

[Arugela]

I assume it's not an issue with COM. All of my engines and fuel tanks are stacked on the same spot. It literally makes my velocity drop to 0m/s and pretty quickly... I can fly and control the ship perfectly. it's just the velocity disappears and I drop back to the ground.

The moment I turn the ISRU off it goes right back to what it was doing. Is it possible it's messing with the engines access to fuel somehow?

On a seperate note, does anyone know how to get twin boar engines to quickly get rid of their heat? Mine are not overheating since I removed some of them an d made my flight times longer. I put radiators and stuff on them but it doesn't do anything useful. They seem to not be able to remove heat in a timely enough matter to actually extend flight time during takeoff and initial orbit... Is there anything that actually gives numbers on heat and radiators affectiveness so we have a chance to actually solve it?

Edited October 29, 2015 by Arugela

[Laie]

Cue Admiral Ackbar: It's a bug!

Check the context menus of your engines and you will see that all but one run at reduced thrust. This happens when you run the converter and more than one engine at the same time, and stops as soon as you turn off the converter.

- - - Updated - - -

On a seperate note, does anyone know how to get twin boar engines to quickly get rid of their heat? [...] Is there anything that actually gives numbers on heat and radiators affectiveness so we have a chance to actually solve it?

ALT-F12 and turning on the thermal data in part menus is the best I know of. It's not very good for your purpose, though.

Other than that, maybe you should reconsider your use of TwinBoars. They're designed to be boosters: comparatively cheap, high thrust per weight, but only mediocre efficiency. Their whole data encourages to use them only for a short time and jettison them quickly -- when used like that, there is no time for them to overheat.

If you start dressing them up with radiators and stuff, have a good long look at the outcome: it may well be that an unadorned Mainsail+Tank is cheaper and more lightweight than a TwinBoar with heatsinks. It certainly has better fuel economy.

[Arugela]

But is there a way to actually slow down the heat with them? I was using radiators and stuff and wasn't seeing any difference. I wasn't sure if that is just the engine or if I likely placing them wrong. I get to like 45k apoapsis before they blow up. I just need to get a little farther.

Technically I placed them on the outside of the ship. Since it's very condensed I didn't technically make sure it was directly on the engine. It could have been on the tank. Does that make a difference atm? I have yet to find proper information on how heat works and how the radiators and panels work with them.

And they did work I just reduced the TWR to save weight and gain DeltaV a bit so this thing could hop around more easily. With the 4 extra engines I had placed they did not blow up before orbit or virtually ever. But they did not get as far because of the base weight increase. I was hoping to keep the ship smaller with the reduced engine count.

Edit: I put up a bigger version with better TWR but it still doesn't easily dissipate heat when you get into orbit. Do you have to have some radiators to do it or should it do it on it's own? I would think several days in orbit and is should lower the heat. But it does not.

Do you need to have extendable panels and passive panels together to make it work or are they like solar arrays and just different versions of each other?

Edit2: I have now put on the largest deployable radiator panels and it does nothing. I spin around kerbin over and over and it does not seem to reduce the engine overheat.. The only thing that reduces the heat is if I get 500k plus past kerbin orbit and it just goes away... What is the point of these panels and heat if they do nothing.

I have 4 engineers on board. Do I need a scientist or something?

Edit3: I just spun it around kerbin from the space center for 34 days with the panels out. It did not budge. How is it acceptable to have this bad of a mechanic in this game. It should not stay hot for 34 days in the cold of space... Sorry, I don't find a mechanic this simple acceptable if they are going to keep it this way stock. I really hope they are going to do something about this if this is not a bug.

Someone please tell me how a bar that fills up once and stays until a given altitude is a system. This is not a working heat system. I swore they said they added these things in 1.0.4..

Update: I have since found out this may have to do with a bad Physics.cfg file related to a desktop shortcut. My phsyics weren't running at all. I actually wasn't dissipating heat at all or seeing atmospheric or other affects correctly.... I may have to redo this and other ships now. So if my designs have been out of sync, this is why.

Edited October 30, 2015 by Arugela