Thread about realism of thermals in crrcsim
-------------------------------------------


From: "Stephen D. Cohen" <sdcohen@...>
Date: Fri Feb 8, 2002  4:11 am
Subject: Reality?

[...]

The question is: How realistic is the performance and thermal signaling of
the Apogee in crrcsim? If I can expect this kind of "Hello, there is a
thermal here" signaling I am gonna get me one and thermal soar it on
Saturday and Sunday afternoons on the golf course behind my house (I can
launch between foursomes and glide above them if I catch a thermal, right?).

So what is the deal? How realistic *is* the thermalling model in crrcsim
and the Apogee implementation? I am using the default thermal parameters:

thermal_strength_mean 5 5 foot per sec average strength
thermal_strength_sigma 1 1 foot per sec 1 sigma variation
thermal_radius_mean 50 50 foot average radius
thermal_radius_sigma 10 10 foot 1 sigma variation
thermal_density 0.5E-5 Thermals/sq ft
thermal_lifetime_mean 240 4 minute average lifetime
thermal_lifetime_sigma 60 1 minute 1 sigma variation

I've been flying with a 7.33 fps breeze (5 MPH).

[...]

----------------------------------------------------------------

From: Jan Kansky <kansky@...>
Date: Fri Feb 8, 2002  6:15 am
Subject: Re: [crrcsim] Reality? 	

Steve,
Let me put it this way... It is certainly true that being able
to find and center thermals in crrcsim (with indicators off) is a
prerequisite for being able to find and center thermals in the
real world.

I programmed in the true vacuum cleaner effect of the thermals
superimposed on the steady wind. This means that the wind shifts
and airplane yawing should all be useful indicators in the sim.
The vertical components of the wind are obviously included as
well. Being able to get a visual sense of the energy of the
aircraft is important, and that is all represented well in the
sim, in my opinion.

The part that is missing is the fact that in the real world
there is a lot of turbulence. Right now, there is no turbulence
in CRRCsim. Becoming an expert HLG pilot requires the ability to
distinguish between the effects of turbulence on the aircraft
from thermals.

Overall, I think that you will find that if you can thermal in
the sim with the thermal indicators off, you will have no
problems in the real world after a bit. I do recommend you try
to get a rc transmitter interface of some sort for better stick
feel.

-Jan

----------------------------------------------------------------

From: "Stephen D. Cohen" <sdcohen@...>
Date: Sat Feb 9, 2002  4:16 am
Subject: RE: [crrcsim] Reality?

[...]

Glad to hear it. Are the default thermal parameters I posted yesterday
typical of a 1) gentle lift day, 2) moderate lift day 3) heavy lift day or
4) strap down the Volkswagens guys, this air will lift *anything* day?

> The part that is missing is the fact that in the real world
> there is a lot of turbulence. Right now, there is no turbulence
> in CRRCsim. Becoming an expert HLG pilot requires the ability to
> distinguish between the effects of turbulence on the aircraft
> from thermals.

I suspect my success rate might be a little lower with the turbulence -
like maybe closer to 1 in 100 times... You had to mention this, didn't you?
I guess I asked...

While I have your attention, one feature that would be really really useful
in crrcsim would be the ability to hit a key and have the simulator point my
head towards the horizon so I can see which way I am facing. Once I leave a
thermal, I am never quite sure which way is up wind. In real life I would
have many visual cues that I do not have in the simulator (little things
like peripheral vision, for example). A way to hit the N key for "nod" or
some such that just showed me what I would see looking horizontally would be
a big help.

[...]

----------------------------------------------------------------

From: Jan Kansky <kansky@...>
Date: Tue Feb 12, 2002  10:59 pm
Subject: RE: [crrcsim] Reality? 	


Steve,

> Glad to hear it. Are the default thermal parameters I posted yesterday
> typical of a 1) gentle lift day, 2) moderate lift day 3) heavy lift day or
> 4) strap down the Volkswagens guys, this air will lift *anything* day?

The default parameters are a pretty strong lift day, with very
localized tight thermals.

[...]

