Air drag in rigidchips

[copy of another post i made some time ago on ridigchips.tk without any replies]

In an attempt to improve WW2-regulated fighters by enhancing propeller efficiency, I tried to get a function able to correlate blade velocity and air drag.

For this task, i've created a scenario which breaks apart a model made out of 500 chips and teleports them to the RC world origin(0,0,0), setting their rotation so they're level with the horizon and applying a constant force on them to find out the terminal velocities.

After plotting ~500kb of data points into it and parsing them into a table, i found out this interesting graph.


[x axis = force applied to each chip in N, y axis = terminal velocity for each chip in m/s, click the image to see its entirety]

As the curve indicates, the air drag behavior actually reverses at higher forces.

This leads to 2 implications:
1 - more power to the propellers may not be always the best choice
2 - ramjets are a possibility in rigidchips.

So far, i was unable to create a working ramjet, as the entire plane also reverses lift direction at the speeds ramjets can work(~mach 2.4, using external mods to increase terminal velocity), rendering control surfaces tricky to use. However, the concept looks promising.

So, theoretically, if you reached a high enough speed, the vehicle would start to accelerate itself without energy input?

Short answer: Yes.

Long answer: Yes, starting at ~800m/s. the default speed limits are 140m/s for the core and 175m/s for other chips - i've used the _SETLIMITVELOCITY function on the Spirytus DLL library to get around these limitations.

I haven't been able to come up with a vehicle able to safely get to these because at these speeds the fuselage also suffers a lot from the effects(it also accelerates itself, until the point it gets below the barrier, realizes it's not supposed to accelerate in such situations then drags down so hard wings get ripped off with unbreakable on). The problem is also worsened off by the fact control surfaces end up inverted, as well as the aircraft stability.

Would you care to link to these things that remove the speed limit? I'm interested in trying this out.

Firstly, you'll need to patch the rigidchips executable with Stolichnaya then get the Spirytus dll library.
(Spirytus's library isn't linked on the wiki article, so i looked the orz uploader to find this version).

after patching the executable(which also allows usage of several functions originally intended for scenarios such as camera and file manipulation) you can call loadlib("spirytus.dll","rc_OpenSpirytus")() in your lua script to load the Spirytus library. keep in mind _SETLIMITVELOCITY is a scenario-scoped function.

If control surfaces are a problem, I'd suggest replacing them with jets.