[1.12.*] Deadly Reentry v7.9.0 The Barbie Edition, Aug 5th, 2021

[Taki117]

You don't need a heatshield on the MK I pod. It has one built in.

[Starwaster]

As stated, the Mk1 pod has a heat shield and does not require one added.

Furthermore re and more importantly, DRE DOES NOT ALTER DRAG AT ALL.

I'm not sure what inverted drag really means but it's an issue for you to bring up with Ferram and not deadly reentry.

[Lei07]

Thanks for your reply! I did also bring it up in the FAR thread, thought best to cover both sides

[indylead]

Calm down, calm down, no need to shout.

We weren't saying the problem was with the Deadly Reentry mod itself, just trying to identify what the problem was. We are aware the capsule doesn't NEED a heat shield, we were investigating the reentry issues of the part. Whether the root cause is the Deadly Reentry Mod, or FAR mod, I have no idea, nor do I particularly care. One of them is borked. I'll let someone else work out which.

I've posted across in the FAR thread with this link to a video showing what happens with that part fitted. I NOW IT IS NOT NEEDED. THAT IS NOT THE ISSUE!

By "inverted" drag, what we meant was the drag direction appeared to be in the opposte direction to expected, i.e. the drag force appears to be acting along the direction of flight, thereby accelerating the ship (as seen in the video) and not acting in the opposite direction to slow the ship. On re-watching the video, I don't think this is what is happening - it seems to me that the FAR data on the heat shield is simply missing, and somehow is not slowing the craft.

Anyway, whether you are interested or not, whatever. Just trying to show a bug somewhere and help someone fix it.

[Starwaster]

Calm down, calm down, no need to shout.

Just because I used caps does not mean I am not calm. They were for emphasis and nothing more. I wanted there to be absolutely NO (see? emphasis. Understand the difference now?) misunderstanding that DREC (acronym... so. caps.) is in anyway affecting aerodynamics. It is absolutely, positively, unequivocally and in every way impossible for it to do so.

[AmpsterMan]

What aerobreaking issues are you refering to? If you mean acceleration as in the video, that is actually a misconception. That increase in velocity happens in Stock KSP as well in the upper layers of the atmosphere. I wish i could offer a clever explanation as to WHY that happens. All i know is that it isn't so much a net increase in velocity, but rather I think it is because now you are having an acceleration "downwards", i.e. if you look at the verticle acceleration it increases.

also {mod hat: ACTIVATE! form of, Mediator!}

Some times, text is inssuficient in translating meaning. Upper cases can mean various things, such as shouting, surprise, or emphasis. A good rule of thumb I use is to assume people mean the most benign meaning when something can have multiple meanings and things usually work out.

{/mod hat: DEACTIVATE! form of, Ignoramous!}

Edited November 5, 2014 by AmpsterMan

[indylead]

My bad, just used to other forum where caps lock is shouting Ferram4 has responded on the other thread - seems to be a clipping issue of the parts, and can be worked around. Thanks for responding.

ETA as AmpsterMan replied after I wrote the above - I realized on re-watching the video that the acceleration was a misconception and not a result of the modelling of drag. I wondered if it was the acceleration of the craft as it closed on the periapsis (and ignoring aerodynamic effect of the atmosphere).

Impressed that two different mod developers and a forum mod have both replied so quickly to the issue at hand - my first foray into this forum and good to see quick replies from folk.

Now, to investigate if Lei's problem was all a ruse to lure me back into playing the game...

You will be happy to know that the video was all a bad dream Bill had on the eve of the launch night. On the 'real' mission, he realized the heat shield was unnecessary and jettisoned it prior to attempting a landing. This was followed by a landing maneuver entirely within acceptable parameters of Kerbal physiology, and Bill will be back on active duty just as soon as someone sends a boat to fetch him.

Edited November 5, 2014 by indylead

[SRFirefox]

I was using DRE as part of Realism Overhaul today and noticed that my replicas of the Falcon 9, F9H, and Energia launch vehicles, all of which have relatively high TWRs on take off (1.3-1.5). My F9 is about as close as I can get it to realistic, weighing just over 500 tonnes at liftoff. Lacking better information than external measurements on the Energia, I'm using known payload mass and external measurements to make a best guess. Problem is, both vehicles reach ~30km at between 800 and 1000 m/s, which is heating components to the point of failure. I'm finding this very odd since the vehicles are well past max Q and as far as I can tell, I'm following something approximating a realistic flight path for the F9 and F9R and doing a best guess burn for 400km on the Energia. I could go higher more quickly, but then I end up burning out well before apogee and launching into a high suborbital path. I could use a little help figuring out what I'm doing wrong.

[Starwaster]

I was using DRE as part of Realism Overhaul today and noticed that my replicas of the Falcon 9, F9H, and Energia launch vehicles, all of which have relatively high TWRs on take off (1.3-1.5). My F9 is about as close as I can get it to realistic, weighing just over 500 tonnes at liftoff. Lacking better information than external measurements on the Energia, I'm using known payload mass and external measurements to make a best guess. Problem is, both vehicles reach ~30km at between 800 and 1000 m/s, which is heating components to the point of failure. I'm finding this very odd since the vehicles are well past max Q and as far as I can tell, I'm following something approximating a realistic flight path for the F9 and F9R and doing a best guess burn for 400km on the Energia. I could go higher more quickly, but then I end up burning out well before apogee and launching into a high suborbital path. I could use a little help figuring out what I'm doing wrong.

I'm assuming Real Solar System here or there wouldn't be much point in using RO? Stock RSS config or something else? (6.4x, 10x Kerbol, etc)

Also, any changes made to DRE configuration: If you have a custom.cfg file in your Deadly Reentry folder, please paste the contents of it here.

[SRFirefox]

Everything is as it came from the factory, and yes, I'm using RSS standard Earth config with RO and all required and suggested mods. Falcon 9 liftoff TWR is 1.21 and Energia liftoff TWR is 1.53. F9 and F9H are launched from KSC and Energia is launched from Baikonur.

[NathanKell]

There's two problems here.

One is that, to make DRE deadly on Kerbin, it *does* look like the heating model may be pumping out a bit much heat. The second, worse, one is that DRE is at best a bandaid on the stock temperature model, which is a *temperature* model, not a heat model. No matter how much or little thermal mass, no matter how much or little heat capacity, KSP and DRE don't know and just apply degrees Celsius as the way to heat things up. Also, the stock dissipation model is quite, quite wrong.

[Starwaster]

Yes yes, but here's another two things:

SRFirefox should still be on a density exponent of 0.85

I've been launching flight after flight for the past week with mostly density exponent 0.8 and maxTemp of 700.

He should be fine...

[redrem]

What Starwaster is saying is that DeadlyReentry does not modify ambient temperature. It adds heating when in an atmosphere, based on the (incorrect) assumption that that atmosphere is Earthlike.

What it does not do, and what RSS can do, is modify the curves that govern ambient temperature; these are ingame variables called temperatureCurves (same format as an atmosphereCurve or any other floatcurve / animationcurve).

However, RealHeat (forthcoming) will try to model solar flux.

When this is made fashions? On heating of kraft from sunlight.

Very much we wait.

Maybe already there is an alpha the version for test?

[SRFirefox]

Just to make sure everything is as-intended, here's a copy of my DRE configuration file.

REENTRY_EFFECTS

{

name = Default

shockwaveMultiplier = 1.0 // multiplier to the temperature of the air due to high velocity.

shockwaveExponent = 1.0 // exponent to (above temperature), applied before above multiplier.

heatMultiplier = 25 // rate at which heat from the shockwave is tranferred to the part

temperatureExponent = 1.03 // exponent to the transfer

densityExponent = 0.85 // exponent applied to air density (heat transfer is also dependent on air density)

startThermal = 750 // the velocity at which the red/orange thermal FX starts appearing

fullThermal = 1150 // the velocity at which it becomes full strength

afxDensityExponent = 0.85 // the exponent to air density for the FX

gToleranceMult = 6.0 // multiplier to the G tolerance of parts, which starts at sqrt(part.crashTolerance * 6)

parachuteTempMult = 0.25 // multiplier to part.maxTemp for burning up deployed chutes

crewGClamp = 30 // Any G level > this is treated as this

crewGPower = 4 // exponent to the G level. G damage is added at a rate of G^power per second

crewGMin = 5 // Any G level < this is ignored for crew damage, and G damage is reset

crewGWarn = 450000 // when G damage reaches this level, warn the player

crewGLimit = 900000 // when G damage reaches this level, start killing crew

crewGKillChance = 0.01 // chance per tick a crewmember will die (if damage is > GLimit)

// any part with a maxTemp over this value will have its maxTemp multiplied

// by maxTempScale.

ridiculousMaxTemp = 2500

maxTempScale = 0.5

}

[Starwaster]

Throttle back in the upper atmosphere would be my suggestion at this point. All of the rockets you cited should have throttleable engines... If not (early Falcon?) then shut an engine down, unless it's a 1 part engine cluster....

Just out of curiosity though, what parts are failing and at what temperatures? It's been months since I used any part of RO other than the heat shield configs so I don't really know what it does to max temp or even if it touches it at all.

Edit: I just ran a test flight with a rocket starting at 1.53 TWR ASL and. I did throttle back a bit approaching 28km (max acceleration at that point was 28m/s throttled back to 24m/s) until I passed 35km. However, I'm running a test version where max temp is capped at 700C. For you the cap is 2500 which is why I asked about specific components and failure temperatures and question whether or not RO might be adjusting those temps.

Also, touching back on what Nathan said a few posts back, (sorry Nathan) but I think that assessment is both overly severe and overly simplified. Yes it's true that the stock heating model leaves something to be desired there are a variety of issues beyond whether or not stock KSP or DRE are modeling heat properly. I don't believe the specific issues being discussed are due to DRE inflicting too much heat on SRFirefox's rockets. I think he's getting a reasonable amount of heat but receiving it to rocket parts that IRL are protected against aerodynamic heating.

As an example, look at the shuttle external tank's 'insulation'. Sure, it protects the propellant contents against excessive heating when the shuttle was on the launch pad, but it also protected against aerodynamic heating where it had to withstand temperatures up to 2200F (just over 1000C). Without that protection, would the tank have been able survive a launch? I don't know, but we don't even really take things like that into account when talking about problems like this. It's not just a matter of whether or not DRE is putting out too much heat or too little, it's also a matter of how much those parts should really be able to withstand. And so far, discussions on that point have been limited to looking at melting or failure temperatures of of the materials and not taking into account the measures put into effect IRL to protect rocket components made out of those materials.

Edited November 6, 2014 by Starwaster

[Jarin]

Having trouble coming in too fast on sub-orbital hops using NEAR. Without the soup to slow me down, I never enter the "safe parachute" speed range before impacting. Any advice?

[Starman4308]

Having trouble coming in too fast on sub-orbital hops using NEAR. Without the soup to slow me down, I never enter the "safe parachute" speed range before impacting. Any advice?

Use FAR and more horizontal hops. FAR's mach effects make for gentler reentries.

[Starwaster]

You can also press alt+D+R and increase the ParachuteMultiplier. Add 0.05 to it at a time until it meets your needs.

[Jarin]

Use FAR and more horizontal hops. FAR's mach effects make for gentler reentries.

But that means learning about all those fiddly bits...

[NathanKell]

No, no it doesn't If your plane flies in NEAR, unless it's a milliplane, it will fly fine in FAR. I really, really don't understand why people assume that modeling less = things are easier, or that a GUI being *present*, even if unopened, somehow makes it ~Le Too Hardz~.

Starwaster: Yes, it's true the ET needs protection. But that means that rocket fuel tanks, and nosecones, and everything else exposed to the airstream should get similar protection, rather than having a destruction point (remember, parts start burning at 85% of max, so the real "death temp" is lower) of about 600C. I say this, having been in 6.4x for a bit and recently returning to RO, where yes, I *do* think that temperature increases too much.

[Starwaster]

Starwaster: Yes, it's true the ET needs protection. But that means that rocket fuel tanks, and nosecones, and everything else exposed to the airstream should get similar protection, rather than having a destruction point (remember, parts start burning at 85% of max, so the real "death temp" is lower) of about 600C. I say this, having been in 6.4x for a bit and recently returning to RO, where yes, I *do* think that temperature increases too much.

Then maybe RO needs special attention in the form of its own DRE config, but I don't use RO myself these days so I'm not sure where it needs help. But without RO, and the current set of configs I'm running with?

Golden.

[Wanderfound]

No, no it doesn't If your plane flies in NEAR, unless it's a milliplane, it will fly fine in FAR. I really, really don't understand why people assume that modeling less = things are easier, or that a GUI being *present*, even if unopened, somehow makes it ~Le Too Hardz~.

Especially with the new tweakable wing strengths; I don't think the broader Kerbal community is yet aware of the significance of that.

The one thing that was legitimately newbie-unfriendly in FAR were the hair-triggered aerodynamic failures. It's now easy to build around that problem in return for a slight weight penalty if desired (and the ultralight option is still there for when you do want a glass speedster...).

It's great for advanced designers, too; I'm having success with using the tailfin mass tweakables to fine-tune CoM height and other such tricks. Now we've just gotta convince Ferram to bring in a more friendly UI than the finicky right-click sliders...

[NathanKell]

Starwaster: if you're only hitting a max of ~3Gs, you're totally missing the issue. Most (early) real life launchers hit 7+Gs on ascent. Heck, Thor-Able (aka Thor-Delta aka Delta) hit over thirteen Gs at burnout, even including residuals. That has absolutely nothing to do with RO.

My main point, however, is this. First you talk about going to ~700C across the board. Then you talk about the shuttle ET being rated for 1000C. It seems reasonable to me to treat nose cones and rocket stages as being similarly insulated.

That said, if you're fed up with this, I'll shut up and just try to get RealHeat working. I don't mean to pick a fight.

Wanderfound: Don't blame ferram, that's my pull request (took all of twenty minutes, IIRC, it was very barebones). Ferram is doing all sorts of magic with wings right now, it'll probably get obsoleted soon.

[Starwaster]

Starwaster: if you're only hitting a max of ~3Gs, you're totally missing the issue. Most (early) real life launchers hit 7+Gs on ascent. Heck, Thor-Able (aka Thor-Delta aka Delta) hit over thirteen Gs at burnout, even including residuals.

I don't think I said I hit a max of 3g, only that I throttled back a bit when I was low to middle atmosphere. That's why I said 'at that point'.

I was also trying to keep my example launch close to the sort of launcher that the guy was talking about that he was trying to replicate which does thottle back at points in its flight. I admit I'm not as familiar with the Thor but it doesn't sound like a good comparison as the launcher in question. Should I try to replicate one?

That said, if you're fed up with this, I'll shut up and just try to get RealHeat working. I don't mean to pick a fight.

I wasn't aware it was a fight...

[NathanKell]

Ah, sorry, you seemed a bit annoyed in your last post and I didn't want to further annoy. :]

It's definitely worth trying some higher-TWR launches heading for LEO (LKO if 10x Kerbin, which IIRC you use rather than RSS). Also, without throttling...

I get persistently quite high temperatures on my fairings (~650C which is beyond the "burning point" if maxtemp is lowered to 700) during the middle of the ascent. And that's with a liftoff TWR of about 1.2; it would be much, much worse for high liftoff TWR LVs (i.e. US solid-assisted LVs).