[0.25] Realism Overhaul w/ RedAV8R [Terminated]

[RedAV8R]

ThorBeorn, they are going to be based on real life data...the curves for a lot of SRBs in the pack have a generic curve, that isn't that friendly...i really need to sit down and get the conversion going from time/thrust to fuel/thrust.

Correct, HoneyFox's plugin no longer required, RealFuels now has the capability.

[ninjaweasel]

If I do a MM database reload, will that force a reload of the .cfg file, or do I have to restart KSP every time I tweak the file?

[ThorBeorn]

Thanks Red. I just deleted my previous post. Found out that thrustcurves now comes with realfuels.

You've taken on a big task with the SRB's alone. If you can get burn time and thrust roughly equal to real world values it's great imo.

We can then use PP SRBs and make our own thrust curves to fill any gaps.

[ThorBeorn]

If I do a MM database reload, will that force a reload of the .cfg file, or do I have to restart KSP every time I tweak the file?

That should be enough now that MM handles reloads fine. Why don't you try and see if it works?

[RedAV8R]

I've noticed that a few things don't play nice with a database reload, there is no guarantees. When I test I have EVERYTHING removed except absolute requirements, keeps load time to a minimum.

@ThorBeorn: That's the problem...burn time is associated with thrust curve...so nothing is accurate until everything is accurate. I REALLY don't like PP SRBs, and honestly...mass, maxthrust, and isp is all there...and accurate, now it's up to a good curve to make it all work right.

Edited August 7, 2014 by RedAV8R

[ninjaweasel]

So,

First off, discovery: MM Database re-load didn't like me. Post-re-load, the mass of those boosters shot up to 1050t. Not cool for testing purposes!

On the EAP-241A thrust curves. My methodology was to use the following goalposts:

Metrics for which I lacked data:

- A satisfactory TWR at launch. I went for about 1.3

- A Max Q similar to the Delta series rockets (roughly 50 KPa)

Data pulled from the user manual:

- 1000 m/s @ 80 seconds

- 2000 m/s @ 120 seconds

- 4.5g Max G loading

- Burn Time of 129 seconds

- Booster Separation @ 100Km (this just helped define the ascent curve, isolating that variable somewhat)

I'm on target for all of these within a reasonable degree of error, with the exception of 2000m/s @ 120 seconds. I blow through that and hit about 2200. But if I turn down the thrust to hit that figure accurately, I blow the burn time figure etc... I don't envy your task if you're going to do this for every SRB out there!

I know this is a very different shape from the default curve and I don't know how realistic that is. I know that SRB thrust/time is controlled by the shape of the combustion chamber and the exposed surface area of the propellant, but I don't know how accurately that can be tuned. That being said, it reasonably emulates the real-world flight profile so... if the shoe fits?

key = 0 0

key = 0.03 0.69

key = 0.1 0.78

key = 0.16 0.85

key = 0.23 0.91

key = 0.29 0.97

key = 0.35 1

key = 0.42 .98

key = 0.48 0.95

key = 0.55 0.91

key = 0.61 0.87

key = 0.68 0.82

key = 0.74 0.76

key = 0.81 0.71

key = 0.87 0.66

key = 0.94 0.63

key = 1 0.6

Edited August 7, 2014 by ninjaweasel
Video

[Ophiuchus]

Here's the actual Araine 5 thrust curve. It needs to start at higher than 1 initially (Ariane has a very high launch TWR), then climb even higher, then go into a thrust bucket at max-Q, then go back up to ~1, and hit ~5% max thrust at "burnout" (burnout is actually when booster TWR<1 or thereabouts). The problem is converting this time curve into a % propellant curve, which will require calculus

[Woopert]

Just a few things regarding the GitHub version of RO.

1. J-2X engine -- was it removed? If so, will you be adding it back? I remember you said you'd like to stick with current engines, so I guess that might be why.

2. The KW Rocketry F-1 and J-2 clusters: the gimbal range on the F-1 shows a gimbal range of 4.8, but in reality it has a range of 6 degrees. The J-2 shows a range of 4 in-game, though I'm not sure what it is in reality. Just noting this one because the FASA J-2 has a gimbal range of 7.5.

3. Was the Apollo service module + RCS thrusters built-in removed by accident? I can't seem to find it.

Thanks in advance!

Edited August 8, 2014 by Woopert

[RedAV8R]

1. Yes it was removed from that individual and will be added to another.

2. Yes the gimbal range was lowered because of force, clustered engines like that don't properly distribute that force as if it were 5 individual engines...now that was before...that theory needs tested again, now that engine logic changed a bit.

3. Shouldn't have been. Haven't gone through FASA or OLDD yet.

[ninjaweasel]

http://i.imgur.com/HT3j5tf.jpg

Here's the actual Araine 5 thrust curve. It needs to start at higher than 1 initially (Ariane has a very high launch TWR), then climb even higher, then go into a thrust bucket at max-Q, then go back up to ~1, and hit ~5% max thrust at "burnout" (burnout is actually when booster TWR<1 or thereabouts). The problem is converting this time curve into a % propellant curve, which will require calculus

Awesome find! Is there a higher resolution? That one got downsized and I can't really read it. I should be able to extract approximate #'s if that's all there is.

I was already thinking about how to convert propellant % to time so that I could tweak numbers more accurately without having to do a test flight just to see when the booster would run out of oomph. I'm not there yet, but with a couple of the right formulas I should have excel doing this for me before too long.

Even to eye-ball it, I shouldn't be too far off.

I think I understand the rationale here. It ramps up to avoid shock-loading on launch, then pushes max thrust to get supersonic, minimizing drag. Makes sense.

[Ophiuchus]

Awesome find! Is there a higher resolution? That one got downsized and I can't really read it. I should be able to extract approximate #'s if that's all there is.

I was already thinking about how to convert propellant % to time so that I could tweak numbers more accurately without having to do a test flight just to see when the booster would run out of oomph. I'm not there yet, but with a couple of the right formulas I should have excel doing this for me before too long.

The propellant consumed should approximate the integral of the time curve, but it's been a decade since calculus so can't help you there And I don't have another size of that graph, sorry. Just what I found on Google.

[NathanKell]

Yes. Given these things are usually more or less piecewise linear you probably should just do piecewise linear integration?

[Ophiuchus]

This curve gives a profile pretty close to the real EAP. Hits max thrust at ~22 seconds, max bucket at 40 seconds, slowly throttles up till 110 seconds, then tails off, hitting TWR=1 at 132 seconds:

thrustCurve

{

key = 0 0.001

key = 0.01 0.01

key = 0.03 0.03

key = 0.035 0.15

key = 0.05 0.3

key = 0.10 0.65

key = 0.20 0.655

key = 0.30 0.66

key = 0.40 0.655

key = 0.50 0.65

key = 0.60 0.62

key = 0.65 0.6

key = 0.70 0.8

key = 0.75 1

key = 0.80 0.98

key = 0.85 0.95

key = 0.90 0.94

key = 0.95 0.93

key = 0.975 0.93

key = 0.985 0.92

key = 1 0.90

}

This thrust curve gives a roughly square-shaped profile that preserves the SRM's overall burn time and leaves about 3% residual propellant, similar to

thrustCurve

{

key = 0 0.01

key = 0.01 0.01

key = 0.03 0.03

key = 0.035 0.2

key = 0.05 0.77

key = 0.10 0.96

key = 0.20 1

key = 0.30 1.015

key = 0.40 1.02

key = 0.50 1.026

key = 0.60 1.02

key = 0.65 1.022

key = 0.70 1.02

key = 0.75 1.025

key = 0.80 1.03

key = 0.85 1.02

key = 0.90 1.03

key = 0.95 1.075

key = 0.975 1.03

key = 0.985 1

key = 1 .88

}

For example, the Atlas V SRM should burn out at 94 seconds; with this profile they cease to produce meaningful thrust at 94 seconds.

Edited August 8, 2014 by Ophiuchus

[RedAV8R]

Alright folks...in the source, grab the latest KW Solids and FASA SRBs/1207 files...Test out the KW UA1207 and the FASA UA1205/UA1207s, let me know what you think! Yep those curves are long, and account for every second of flight.

I'll make it easy...download THIS, save to main RO folder, then THIS, and THIS and replace in the RedAV8R/FASA folder.

Edited August 8, 2014 by RedAV8R

[ninjaweasel]

Yes. Given these things are usually more or less piecewise linear you probably should just do piecewise linear integration?

I was thinking that calculating area under the curve should be the easiest thing. Since total area under the curve = 100% fuel burnt, I should be able to average one fuel % interval to the next to calculate time. Since the problem has been solved for the booster I was working with, I'll give that a try on the next build I do.

[Ophiuchus]

Alright folks...in the source, grab the latest KW Solids and FASA SRBs/1207 files...Test out the KW UA1207 and the FASA UA1205/UA1207s, let me know what you think! Yep those curves are long, and account for every second of flight.

I'll make it easy...download THIS, save to main RO folder, then THIS, and THIS and replace in the RedAV8R/FASA folder.

Edited August 8, 2014 by Ophiuchus

[RedAV8R]

@ninjaweasel: and @Ophiuchus: and @EVERYONE!: Alright everybody, I have a working method which produces awesome results (as long as other specifications like max thrust and what not are correct) SO all I need are pictures of thrust curves, time based is the usual, I can work around something else just as easy. PLEASE everybody link images of thrust curves for me, sometimes THAT's the hard work is just the research for that, here I will rely on everybody as my team!

Seriously guys, stop trying to come up with them. I have a program now that automatically gathers data points from a curve with minimal effort (no guessing now), and then exports that data to an excel sheet which calculates fuel burn and creates the fuel remaining vs. thrust curve. The results as I said (as long as other key info is right) makes a curve that is data generated with no guesswork, and testing and matches the curve every second of flight. Don't believe me get the UA1205 curve and you can literally follow your flight and watch your thrust vs time perfectly match that on paper. It's giggle fantastic.

[mecki]

This is great news, RedAV8R!

Another short question on balancing: Are the Remote Tech2 antennas being balanced by RO? Or need they to be furtherly tweaked? 10Mm for biggest range omni antenna is OK?

Thank you!

[Ophiuchus]

It's giggle fantastic.

I had no doubt you would, the thrust profiles were to play with until we get some usable boosters

Castor 30

Castor 120

[RedAV8R]

@mecki: Yep, RT2 for the time being is as they should be. We've got some plans for the future, but that's on the back burner for right now.

@Ophiuchus: GREAT, keep it coming! One thing to keep in mind the larger the actual picture, the more accurate the thrust curve will be, so even if you have to link a file or page that it's on, if the original is larger that will benefit everybody.

Edited August 8, 2014 by RedAV8R

[Ophiuchus]

Are the Remote Tech2 antennas being balanced by RO? Or need they to be furtherly tweaked? 10Mm for biggest range omni antenna is OK?

Thank you!

If you put more than one antenna on your craft, the range adds up

[mecki]

If you put more than one antenna on your craft, the range adds up

you made me laugh

[Ophiuchus]

Yup, these are all at the highest quality I could find them

you made me laugh

All my comsats look like sea urchins

Edited August 8, 2014 by Ophiuchus

[Ophiuchus]

Jackpot: thrust curves for every ATK SRM

http://www.ltas-vis.ulg.ac.be/cmsms/uploads/File/DataSheetSolidATK.pdf

[mecki]

Sorry to start with the antennas again but I'm mildly confused: The Communotron states to have an omni range of 8.00 Mm (which is 8000km if I'm not mistaken?). However I was connecting to a vessel that is 21000 km away. What did I do wrong?

EDIT:

All my comsats look like sea urchins

They don't really add up, do they? This can't be how it works…

Edited August 8, 2014 by mecki