Question on FMS file types

[HankF]

Where can I get a description of the various FMS file types and what they are for (ie, .PAR), and how they are generated?

In particular, I downloaded a Voyager_E heli model but it initializes with the skids buried in the runway. In which file type is the initial position handled and does it require a specific editor (such as Metasequoia) to generate it?

[Flying Baer]

Hello Hank,
to the first question: look at this site www.rc-sim.de under FAQ - FMS PAR-Datei.
and to the second question: the last parameter in the par-File show the high from the runway.

Par-Designer can you find on my Web-Site under Tool´s
[url=http://members.tripod.de/flying_baer

greetings]http://members.tripod.de/flying_baer

greetings[/url]
Flying_Baer

[HankF]

The .PAR file definition under the FAQ seems to be about airplanes, not helis. The last parameter in the heli .PAR file is one of nine points. I don't know what they are for. Unfortunately, the PARdesigner's help menu is in Japanese of which I know nothing.

When the Voyager_E model I downloaded from the FMS site initializes, as said before, buried in the runway, it immediately collides and does another initialization (a reset). This continues over and over. Do I have to modify the Z value in all nine points of the .PAR file to correct this? Does Z indicate vertical?

In general, how does one insure that the mathematically defined vehicle corresponds to the geometrically defined (visual) model?

[johnhlong]

The voyager is a 3d helicopter.
If you start with no throttle you are actully giving it down pitch, so it wants to crash into the ground.
Start it with aboit 1/4 - 1/3 throttle and see what happens.

Remember, with the helicopter you control the pitch and the throttle (RPM) is fixed in FMS.

If you want to translate the Japanese try

http://babel.altavista.com/translate.dy ... .rc-sim.de

Hope this helps.
John
Seattle, WA
USA



(Edited by johnhlong at 1:14 am on Jan. 10, 2002)

[HankF]

Thanks John, and hello from across Lake Washington: You are right about mid throttle being zero pitch. The heli still has its skids buried in the tarmac, though. Does anybody know which of he Heli .PAR values controls the initial height of the model in FMS?

[Shinichiro_Nishiya]

A heli par-file has some points on the bottom of the model. (i.e. skids and tale)
You can arrange the landing position (vertical axis) to change the value of the PosZ.
PosZ is a parameter of the distance between the bottom points of model and the CG.
I made each PosZ longer in the Voyager's par-file to avoid the buried skids.
I added -0.1 to the all PosZ. (It means made the distance longer)

Mr. Masuoka explained about the par-file of helis.
He uploaded it on his website (in Japanese)

Sorry, I don't understand his explanation exactly.
I hope you will understand my incorrect English.
Please try this par-file

Shinichiro Nishiya
Aomori city, Japan



1 iModelStyle (0 = airplane / 1 = helicopter)

2 mass (MASS) [ kg ]
0.05 moment of inertia around the vertical axis (fIHochachse)
0.05 moment of inertia around the transverse axis (fIQuerachse
0.05moment of inertia around the longitudinal axis (fILaengsachse)
2.2 rotation resistance

35 exponentially nod (expnick) [ % ]
35 exponentially roll (exproll) [ % ]
0 greed (more expgier) [ % ]
15 exponentially pitch (exppitch) [ % ]

0.6 length of a main rotor blade (lRot) [ m ]
0.04 surface of the entire main rotor (aRot) [ m^2 ]
2200 revolutions per minute of the main rotor (upmRot) [ 1/min ]
0.10 collectives blade control of the main rotor (akol) [ wheel ]
0.011 cyclic blade control nodding the main rotor (azykln) [ wheel ]
0.011 cyclic blade control roles of the main rotor (azykln) [ wheel ]
0.10 height of the Rotos over the emphasis (hRot) [ m ]
0.001 back turning inclination by horizontal incident flow (fhorzd)

0.18 length of a tail rotor blade (lRoth) [ m ]
0.020 surface of the entire tail rotor (aRoth) [ m^2 ]
5300 revolutions per minute of the tail rotor (upmRoth) [ 1/min ]
0.12 collectives blade control of the tail rotor (akolh) [ wheel ]
0.011 basic angles of incidence of the tail rotor (alpha0h) [ wheel ]
0.9 distance of the tail rotor axle of the emphasis (LH) [ m ]
0.25 greed inclination by lateral incident flow (fhorzdh)

0.05 sensitivity of the gyroscope (hstab) [ rad/(rad/s) ] / / - 0.007 = 0%. 0.05=100%
80 per cent of fading out the gyroscope with was appropriate the tail rotor (hstabdel) [ for % ]

6.2 lift rise (DCA)
1 max. coefficient of lift (camax)
-1 minimum coefficient of lift (camin)
0.02 coefficient of drag with zero lift (cw0)
0.02 resistance rise (dcw)
0.3 coefficient of drag of the trunk (cwR)

9 points of chassis:

0.3 PosX
0.3 PosY
-0.25 PosZ
1.0 strive
2000 h [ N/m ]
10 muev
800 fmax

0.3 PosX
-0.3 PosY
-0.25 PosZ
1.0 strive
2000 h [ N/m ]
10 muev
800 fmax

-0.2 PosX
-0.2 PosY
-0.25 PosZ
1.0 strive
2000 h [ N/m ]
10 muev
800 fmax

-0.2 PosX
0.2 PosY
-0.25 PosZ
1.0 strive
2000 h [ N/m ]
10 muev
800 fmax

-0.8 PosX
0 PosY
-0.19 PosZ
2 strive
2500 h [ N/m ]
10 muev
50 fmax

0.5 PosX
0.5 PosY
0.0 PosZ
2 strive
2500 h [ N/m ]
10 muev
5 fmax

0.5 PosX
-0.5 PosY
0.0 PosZ
2 strive
2500 h [ N/m ]
10 muev
5 fmax

-0.5 PosX
-0.5 PosY
0.0 PosZ
2 strive
2500 h [ N/m ]
10 muev
5 fmax

-0.5 PosX
0.5 PosY
0.0 PosZ
2 strive
2500 h [ N/m ]
10 muev
5 fmax

[HankF]

Thank you, Shinichiro-san: Could you tell me what the nine (or other value) points are for? Does this have to do with collision detection?

[johnhlong]

Yes please help us understand the 9 points at the bottom of the heli par file.

Is there always 9 points or can there be a different number?

What do each of the sub-items represent:
-0.5 PosX
0.5 PosY
0.0 PosZ
2 strive
2500 h [ N/m ]
10 muev
5 fmax


Thanks again for all the help.

John
Seattle,WA
USA

[shinichiro nishiya]

Hi,
Mr. Masuoka says about the 9 points in his website as blow.
According to his analysis 4 for up part of the skids, 4 for down part of the skids and 1 for the tail-rotor.

I will show you more information of Mr. Masuoka's analysis about the 9 points and sub items later.
Give me time to translate in English.

Shinichiro Nishiya
Aomori city, Japan

[johnhlong]

Thank you. I look forward to your next update.

John
Seattle, WA.
USA

[shinichiro nishiya]

I translated Mr. Masuoka's analysis on the par-file of helis.
This refers to the 9 points and the sub items.

Line 34:nb (cobra=9)
The number of the points on the bottom part of the model
This is for calculating to land.
You need to input all PosX through fmax for each bottom points.
In the case on 9 points, it is supposed that 4 points for under part of the skids, 4 points for upper part of the skids and 1 point for tail rotor.
Line 35:PosX (cobra=0.3m)
An X-axis distance from the CG (origin point) in front and behind
Lin 36:PosY (cobra=0.3m)
A Y-axis distance (right-and- left) from the CG
Line 37:PosZ (cobra=-0.15m)
A Z-axis distance (up-and-down) from the CG
You need to adjust it to make the landing position naturally.
Line 38:muh (cobra=1)
A coefficient of friction against land
You can have the model running by input it smaller.
You need make the all points have the same number to run it straight.
Line 39:h (cobra=2000N/m)
Hardness of the bottom points as landing springs
Making it smaller makes soft landing and making it harder makes hard landing.
Too small input makes vibration.
Line 40:muv (cobra=10)
An ability of shock observing on landing
Making it bigger makes smaller bounce as it has a soft landing gear.
Line 41:fmax (cobra=800)
Strength against destruction of the bottom part points of a model
If the shock of the landing is bigger than this, the FMS will stop.
When you make the hardness (h) bigger, you need to make fmax bigger because the shock will be bigger even if it is in the same speed.
The values on the points under part of the skids have bigger value, and the other points have smaller values.

I am afraid if you will understand my English and I am afraid that I didn't translate his words exactly.

Shinichiro Nishiya
Aomori city, Japan