Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Drag and heating #4657

Open
mike-f1 opened this issue Aug 5, 2019 · 0 comments

Comments

@mike-f1
Copy link
Contributor

commented Aug 5, 2019

Disclaimer: I don't know if an issue is too much of effort for this, but I can't find any better...

Observed behaviour

Drag heating (and only drag heating) is calculated in a fancy way:

pioneer/src/Ship.cpp

Lines 1034 to 1039 in c469f57

// TODO: fix this to calculate appropriate skin friction and heating.
//const double dragCoeff = DynamicBody::DEFAULT_DRAG_COEFF * 1.25;
//const double dragGs = CalcAtmosphericDrag(GetVelocity().LengthSqr(), GetClipRadius(), dragCoeff) / (GetMass() * 9.81);
//return dragGs / 25.0;
// TODO: fix this to properly account for heating due to air friction instead of G-force.
double dragGs = GetAtmosForce().Length() / (GetMass() * 9.81);

as outlined on comments.

Expected behaviour

Something more real, which some hints are here

Steps to reproduce improve

Sources to be considered are friction and radiance, where first constribution should be calculated on these basis (which are used here), and second should come from an execise I did long (...and long, long...) time ago in which the temperature rise of a wall is calculated from heat power and distance from light source (IIRC, it was pretty straightforward...).

My pioneer version (and OS):
current master

EDIT:
Some additional links on that theory:

https://aviation.stackexchange.com/questions/23747/what-is-the-typical-temperature-of-an-airliners-hull-during-flight/23783#23783

https://aviation.stackexchange.com/questions/1640/what-is-the-difference-between-oat-rat-tat-and-sat?noredirect=1&lq=1

https://en.wikipedia.org/wiki/International_Standard_Atmosphere

and a couple of considerations:

  1. Last implementation of the formula (...mine's) is wrong because the effect of wheels should be included in drag calculation. A proof is that the maximum speed of a ship don't change with wheels status
  2. An additional error is that the temperature of the ship is not related to the atmosphere temperature. This due to the fact (IMO) that ship heating has been included in game only for historical and gameplay reasons, but with the above could become a part of the simulation.
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Projects
None yet
2 participants
You can’t perform that action at this time.