Bell 412

[bomber]

Currently, the mast torque in a rotorcraft mast, such as a helicopter mast, is measured by measuring the rotational phase shift, or torsion, between a precision gear attached to the top of the helicopter mast and an identical precision gear attached to the bottom of the helicopter mast. The rotational phase shift between these two gears, which is caused by the twisting of the helicopter mast, is measured using an inductance device.

Ok simply put.. you attach a small AC motor at the top and at the bottom of the shaft (they're going to be run as small generators)... with no mast torque the AC output waveforms will be in sync, however as soon as there's twisting of the mast, ie the rotor head lags behind the engine end of the shaft due to the resistance forces being applied on the blades the waveforms will go out of sync, and a simple syncroscope can be used to show this..

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

[bomber]

So a thought on how one might go about creating the data needed for such an instrument...

a prop, yes I know not a rotor but bare with me can be defined as

Code: Select all

v/(nD)   v/(ΩR)   Ct   Cp   Cs   Tc   Pc   η   η*   stalled   v   rpm   Power   Thrust   Torque
[-]   [-]   [-]   [-]   [-]   [-]   [-]   [%]   [%]   [%]   [m/s]   [1/min]   [kW]   [kN]   [Nm]
0   0   0.112115   0.054598   0.000056   9.999999   9.999999   0.01   0.01   4.00 !   0   2391   75   2.173   299.5
0.05   0.016   0.104577   0.05778   0.088433   9.999999   9.999999   9.05   17.35   99.00 !   3.48   2347   75   1.952   305.2
0.1   0.032   0.1131   0.054248   0.179111   9.999999   9.999999   20.85   30.51   4.00 !   7.1   2397   75   2.202   298.8
0.15   0.048   0.1115   0.055037   0.267892   9.999999   9.999999   30.39   42.03   2.00 !   10.6   2385   75   2.15   300.3
0.2   0.064   0.109289   0.055782   0.356231   6.957536   9.999999   39.18   51.61   0.00 !   14.07   2374   75   2.088   301.6
0.25   0.08   0.106339   0.056638   0.443934   4.332621   9.230556   46.94   59.61   0   17.5   2362   75   2.011   303.2
0.3   0.10   0.10   0.057253   0.531572   2.902706   5.399743   53.76   66.33   0   20.93   2354   75   1.927   304.3
0.35   0.111   0.097825   0.057347   0.619964   2.033537   3.406   59.7   72.03   0   24.4   2353   75   1.835   304.4
0.4   0.127   0.092387   0.056991   0.709413   1.470377   2.267593   64.84   76.84   0   27.94   2357   75   1.74   303.8
0.45   0.143   0.086231   0.056055   0.800738   1.084368   1.566439   69.22   80.93   0   31.61   2371   75   1.642   302.1
0.5   0.159   0.07918   0.054261   0.895514   0.806518   1.105395   72.96   84.45   0   35.51   2396   75   1.541   298.9
0.55   0.175   0.071791   0.051865   0.994004   0.604346   0.793823   76.13   87.42   0   39.65   2433   75   1.44   294.4
0.6   0.191   0.064189   0.048889   1.097261   0.454044   0.576359   78.78   89.92   0   44.11   2481   75   1.339   288.7
0.65   0.207   0.056473   0.045346   1.206717   0.34037   0.420475   80.95   92.01   0   49   2544   75   1.239   281.5
0.7   0.223   0.048533   0.041154   1.325   0.25222   0.305532   82.55   93.79   0   54.51   2628   75   1.136   272.6
0.75   0.239   0.040399   0.036288   1.45582   0.18289   0.21904   83.5   95.3   0   60.9   2740   75   1.028   261.4
0.8   0.255   0.032089   0.030725   1.605428   0.127679   0.152815   83.55   96.6   0   68.67   2897   75   0.913   247.3
0.85   0.271   0.023613   0.024439   1.78567   0.083225   0.101338   82.13   97.7   0   78.74   3126   75   0.782   229.1
0.9   0.286   0.014982   0.01741   2.023412   0.047101   0.060814   77.45   98.66   0   93.36   3500   75   0.622   204.6
0.95   0.302   0.006205   0.009617   2.40501   0.017509   0.028563   61.3   99.49   0   120.1   4266   75   0.383   167.9
1   0.315   -0.00102   0.002719   3.226722   -0.00265   0.007135   0   99.99   0   190.7   6500   75   -0.146   110.2
1.05      -0.009797   -0.005074

the last collumn of numbers being important in this case

Code: Select all

v/(nD)   Torque
[-]      [Nm]
0      299.5
0.05      305.2
0.1      298.8
0.15      300.3
0.2      301.6
0.25      303.2
0.3      304.3
0.35      304.4
0.4      303.8
0.45      302.1
0.5      298.9
0.55      294.4
0.6      288.7
0.65      281.5
0.7      272.6
0.75      261.4
0.8      247.3
0.85      229.1
0.9      204.6
0.95      167.9
1      110.2

so you might be able to use an engine torque value (don't know what type of engine you're using) or the prop forces torque and see if there's any slippage between these 2 values and use this.

This is real conjecture at this stage mind

Simon

p.s. I really hate trying to show this type of data, as it's hard to make it look correct... any help appreciated

[valery]

thank you Bomber, I'm about to think about the engines nasal, I study the chopper dynamics and come back with your material. Hard step, not really funny, but interesting anyway.

[Octal450]

This is gold! GREAT JOB!

[valery]

Hi guys,

some progress: one f. day to make some lights effect ... :/ !!
But external lighting is done now, ... pretty done (I forgot the tail nav) :
Beacons Gyro (top/down) and Nav lights (left, right, green red, white)


... and the 2 OH controls too !


Has you perhaps could see, no electrical buses yet, it's coming. Do you know what ?
The Bell has 2 buses with 2 different voltage each. A DC/24V and an AC/110V ! WTF ?!!
I'm trying to mimic the virtual electrical buses from the amazing 707, don't know for what the AC is expected.
The engines model is not done yet, I was looking for electrical functionalities before anything else.

Some propeller/blade effect are done too:
Engine Off:


Engine On:


Enough for today.

Val.
[EDIT]: I forgot : light texturing for instruments in progress ...!:
w/o light:

with light:

[legoboyvdlp]

Most planes have AC / DC

[valery]

Thanks, I don't knew it. I know a bit on sailing boats, 12 or 24DC, I was thinking it was the same for airplanes. Wrong, sure ! )

[legoboyvdlp]

Ah!

Yes, I don't want 110V near my head :O

[IAHM-COL]

That green light in the ALT looks brilliant!

[bomber]

Are you sure it's 110V ac ?
Could it not be dc off the starter bstteries with a 24V tap.