any helicopter par experts? - i need help figuring this out!

[verymadmax]

i am making a par and my heli is sinking into the ground and crashing. i am using the freeware software ParDes. i have tried editing the points to get it to lye flat on its feet but it will not. i have no idea what pionts are were on the heli. i have no idea what coordinates affect what and what does all the other stuff like displacment do? could somebody tell me and everybody else the answers. i think a how to section should be made on this site so the answers could be posted there.

any help would be great.

[johnhlong]

1: You are most likely crashing because you start with negative pitch (Throttle all the way down) on a helicopter that has a large negative pitch for 3d stunts.

2: you could maybe adjust the height of the helicopter above the ground.

3: There have been discussions of all the helicopter PAR entries about a month or two ago. Search this board for them.

John

[johnhlong]

I searched for "Helicopter PAR".

The post I am refering to was on about 12 Nov 2001.
In MODELS
Titled "Mods to the .par file"

Hope this helps.

John

[verymadmax]

i have already mad it so that the heli can have no down thrust. it is a piccolo. the problem used to be that it sat to high so i tried to lower it. what i need to know is what changes the height of the model when sitting on the ground.

[Mr P Trog]

Line 35 down in the par file discribes the Points of the Helo. They have nothing to do with the graphic 3d image. you have to discribe them. POSZ in each group discribes how far below the models center of gravity the point is. I useualy discribe four points for the landing skid and one for the tail rotor, then 3 or 4 for the rotor disk. email me for a copy of my LMH110+ that has four different par files for the different versions of the model.(I have an upside down trainer in a stick cage that flops all over the place on its 5 points. just remember to invert the tail, nick and pitch before you fly it.)

Here is my english translation of the Helicopter Par file.


1 iModelStyle (0 = airplane / 1 = helicopter) {1}

5.5 mass (MASS) [ kg ] {2}
0.05 moment of inertia around the vertical axis (fI vertical axis) {3}
0.05 moment of inertia around the transverse axis (fI transverse axis) {4}
0.05 moment of inertia around the longitudinal axis (fI longitudinal axis) {5}
2.2 rotation resistance {6}

35 exponentially nod (exp nod) [%] {7}
35 exponentially roll (exproll) [%] {8}
0 exponentially greed (exp greed) [%] {9}
0 exponentially pitch (exp pitch) [%] {10}

0.65 length of a main rotor blade (lRot) [m] {11}
0.04 surface of the entire main rotor (aRot) [m^2] {12}
1800 revolutions per minute of the main rotor (upmRot) [1/min] {13}
0.10 collectives blade control of the main rotor (akol) [wheel] {14}
0.016 cyclic blade control nodding the main rotor (azykln) [wheel] {15}
0.016 cyclic blade control roles of the main rotor (azykln) [wheel] {16}
0.10 height of the Rotos over the emphasis (hRot) [m] {17}
0.001 back turning inclination by horizontal incident flow (fhorzd) {18}

0.18 length of a tail rotor blade (lRoth) [m] {19}
0.020 surface of the entire tail rotor (aRoth) [m^2] {20}
4800 revolutions per minute of the tail rotor (upmRoth) [1/min] {21}
0.12 collectives blade control of the tail rotor (akolh) [wheel] {22}
0.009 basic angles of incidence of the tail rotor set. to neutralize rotation (alpha0h) [wheel] {23}
0.9 distance of the tail rotor axle of the emphasis (LH) [m] {24}
0.10 greed inclination by lateral incident flow. weather vaneing of tail roter. low = heading lock(fhorzdh) {25}

0.05 sensitivity of the gyroscope (hstab) [rad/(rad/s)] -0.007 = 0%, 0.05=100% {26}
100 per cent of fading out the gyroscope with was appropriate for 0.05 sensitivity of the gyroscope (hstab) the tail rotor (hstabdel) [for%] {27}

6,2 lift rise (d approx.) {28}
1 max. coefficient of lift (of approx. max) {29}
-1 minimum coefficient of lift (approx. min) {30}
0.02 coefficient of drag with zero lift (cw 0) {31}
0.02 resistance rise (d cw) {32}
0.3 coefficient of drag of the trunk (cw R) {33}

9 points of chassis: {34}

0.3 PosX {35} (Right Front Gear)
0.3 PosY {36} (Y positive is right when viewed from behind)
-0.15 PosZ (Describes height of model from models center of grav.) {37}
1.0 strive (Drag of gear) {38}
2000 h [ N/m ] (It is rigidity, as a compressed spring of the body point.) {39}
10 muev (It is, landing energy absorption quality of the body point.) {40}
800 fmax (It is, breaking strength of the body point.) {41}

0.3 PosX {42} (Left Front Gear)
-0.3 PosY {43} (Y negative is left when viewed from behind)
-0.15 PosZ (Describes height of model from models center of grav.){44}
1.0 mueh {45}
2000 h [N/m] {46}
10 muev {47}
800 fmax {48}

-0.2 PosX {49}
-0.2 PosY {50}
-0.15 PosZ (Describes height of model from models center of grav.) {51}
1.0 mueh {52}
2000 h [N/m] {53}
10 muev {54}
800 fmax {55}

-0.2 PosX
0.2 PosY
-0.15 PosZ (Describes height of model from models center of grav.)
1.0 mueh
2000 h [N/m]
10 muev
800 fmax

-0.8 PosX
0 PosY (tail rotor)
-0.09 PosZ
2 mueh
2500 h [N/m]
10 muev
50 fmax

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

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

[coptervortex]

Doesn't editing the downward thrust stop it climbing inverted as fast?

[Astro]

silly question, but are you using a tx or the keyboard controls? reason I ask is that standard keyboard set up has a constant throttle setting and variable pitch, meaning that at 'idle' ie the setting when you load the model, the default pitch setting may be negative. Try increasing the positive pitch (either on your tx or by holding the 'g' button down) and reloading the model at the same time. I had the same thing happen and this seemed to solve the problem.