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Re: Dead Simple Human Powered Aircraft model v1.0

Postby wkitty42 » Wed Oct 07, 2015 12:13 am

adding more batteries to a circuit to increase voltage or current may or may not increase work done... if the motor is designed to use X voltage at Y current draw and provide Z output of work done, then adding more batteries won't help... Ohm's Law is in play...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby abassign » Wed Oct 07, 2015 5:02 am

Unfortunately, the lack of definition in Jsbsim complete system consists of the electric motor and batteries, makes everything much more complicated. Not only for the conception of a hybrid aircraft (Human - Electric), but also for the correct definition of the power which can produce the athlete! It seems proper to propose to use an application written in NASAL, but you must able to join the parameter "instantaneous power to propeller" with the parameter product NASAL. This knowledge is needed in both cases is that we want to simulate a human flight pure or hybrid. I think the best thing is to pose the question in the forum that deals with problems related FDM to see if the problem can be solved without need change the Jsbsim.

In an undergraduate degree in Mechanical Engineering from the "Politecnico di Milano" I found some very useful diagrams to describe more correctly the power produced by an athlete during the ride and how this changes with time.

This diagram shows the consumption and the power that produces an athlete while pedaling. As can be seen the weight, especially for high powers, it is advantageous, but not too much .. if the speed (pedaling) is not high. Since a plane must go up, the weight must be low, and therefore the advantage of an athlete heavy and powerful, might not be so important.

Image

This diagram is very interesting because it puts in relation the power, pedaling speed with the maximum time of the effort. Notice how the maximum power (250W) last only 15 seconds! The diagram also tells us that the idea of applying 1000W continuous, does not work! The power which can give a trained athlete is much lower and for times much smaller.

Image

This diagram shows us that human is made to run! Ie the maximum power occurs with a high rate of pedaling, and thus this requires that the propeller should be a variable pitch, or there must be a mechanism that decouples the pedaling rhythm respect the rpm of the propeller of the aircraft. This was the reason why I believe that a human flight has only sense with a hybrid system, because can be recharged the battery initially with moderate effort, then use this potential energy accumulated to take off the aircraft. For purists of the bike, what I say I may sound blasphemous, but I have to remember that the bike does the same thing as the power of pedaling is partly used to compensate for friction and partly converted into dynamic energy (speed).
Of course if I were to make an athletic competition, if I were a jury, I would do ensure that the initial charging of the batteries is zero or at a level equal for all competitors.

Image

This diagram reminds us that the power that can give an athlete is not infinite and it is also surprising that long times of stress, the difference of a well-trained athlete is not so high compared to a healthy athlete, but not trained. This is a diagram that tells us that flying long is difficult if you do not take advantage of other energy funds, such as thermal dynamics, the sun.

Image
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby Thorsten » Wed Oct 07, 2015 5:54 am

Unfortunately, the lack of definition in Jsbsim complete system consists of the electric motor and batteries, makes everything much more complicated. Not only for the conception of a hybrid aircraft (Human - Electric), but also for the correct definition of the power which can produce the athlete!


JSBSim is a physics simulation engine. I can write a fuel cell in it, including the consumption of hydrogen and oxygen, output of water, resulting voltage, temperature, failure modes,... I can write an APU system in it, including hydrazine ignition conditions, fuel consumption, temperatures of the gas generator bed, exhaust stream, lube oil, hydraulic fluid, valve settings, failure modes... I'm sure it manages a battery.

Of course there's no complete electric power source pre-defined - just use some basic equations and write the one you need.
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby wlbragg » Wed Oct 07, 2015 6:20 am

The original version of this aircraft was setup with a 600 watt power source. It was subsequently increased to 1000 watts.

ggg wrote in Mon Nov 24, 2014 6:54 am:All the potential pilots can sustain 200W-300W (depending on body weight) for at least 10 minutes and several can sustain this output for hours. "Only" need 220-280W (130-180lbs) to maintain level flight per Alec Proudfoot's computation.

cheers
grant


So for the base aircraft (human powered flight) these are the parameters I am going to work with. Anything greater will have to be a hybrid, selectable in the GUI.

Thank you Thorsten for your input. After seeing what you have programmed in the Shuttle, I was pretty sure what abassign was stuck on was not a limit of JSBSim. However, it is definitely a limit of my skills .
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby Thorsten » Wed Oct 07, 2015 6:34 am

if you have the physics model (=equations) of how the engine/battery/human... should work, I can give you the pointers how to do it in JSBSim. But I don't have the time to explain the physics.
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby abassign » Wed Oct 07, 2015 9:02 am

Thanks for your help :)! For equations, there are no problems (As you can see I've already found the material that should help define properly a motor that uses human energy ... as a parameter input, would put the weight and the level of training in order to make more realistic features), that's my job even professional, my desire is just figure out how to put these equations in jsbsim, just wondering if there's an example. Then there is the problem of the electric motor driven by the throttle of the aircraft, at this point I think it would be better to configure an XML code that implements the electric motor on my own by the equations that can be solved at jsbsim. I do not know if I was clear enough.
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby AndersG » Wed Oct 07, 2015 2:01 pm

It seems you didn't get that you can break the connection between the user's throttle input device and the throttle position sent to the JSBSim engine.
Just use a component that outputs whatever to fcs/throttle-pos-norm[X].
Example from ZLT-NT:
Code: Select all
  <actuator name="fcs/etc/throttle-actuator[0]">
   <input>fcs/etc/throttle-controller-pid[0]</input>
   <clipto>
    <min>0.0</min>
    <max>1.0</max>
   </clipto>
   <output>fcs/throttle-pos-norm[0]</output>
  </actuator>


That said, IIRC the JSBSim "electric" engine is not really a good electric engine/motor simulation (IIRC there is no RPM limit etc) - it is rather a directly controllable power source which may well be a very useful component when creating your own engine simulation as a JSBSim system.
It is possible to abuse the JSBSim piston engine starter as a more realistic electric engine/motor model.
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby wlbragg » Wed Oct 07, 2015 9:01 pm

I must be an idiot, I just spent an hour trying to capture the space bar, (or any key for that matters), I tried several.

I started out using
Code: Select all
<keyboard include="Aircraft/DaSH/Systems/keyboard.xml"/>

and a .nas file for handling the key press actions.
Code: Select all
    <nasal>
        <dash>
            <file>Aircraft/DaSH/Nasal/keyboard.nas</file>
        </dash>
    </nasal>


When all that failed I went back to basics and included
Code: Select all
    <input>
        <key n="32">
            <name>Space</name>
            <desc>Test</desc>
            <binding>
                <command>nasal</command>
                <script>
                    gui.popupTip("Test Worked");
                </script>
            </binding>
        </key>
    </input>

right in the -set.xml file. But I get nothing.

What am I missing?
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby MIG29pilot » Wed Oct 07, 2015 10:33 pm

Dont want to sound like the amateur clamouring for the download button, but.. I am an amateur and where's the download button?
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby wlbragg » Wed Oct 07, 2015 11:47 pm

MIG29pilot wrote in Wed Oct 07, 2015 10:33 pm:Dont want to sound like the amateur clamouring for the download button, but.. I am an amateur and where's the download button?

It's in fgaddon.
https://sourceforge.net/p/flightgear/fgaddon/HEAD/tree/trunk/Aircraft/DaSH/

But you can't have it unless you tell me why my key event isn't working :lol:
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby wlbragg » Wed Oct 07, 2015 11:53 pm

I am getting really perturbed here.

This works, but I don't really want to use it this way ( and I know their is a better timer function, this was just a quick test to see if I could get any key capture to work).

Code: Select all
keyHandler = func {
   #space = peddle
   if( getprop("devices/status/keyboard/event/key") == 32){
       gui.popupTip("Test Worked");
   }
   settimer( func { keyHandler() } , .5 );
}
keyHandler();
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby wkitty42 » Thu Oct 08, 2015 3:19 am

if it works, what is the problem? why does it even have a timer?
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"Dunno. It's frightened of heights, I guess."
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby wlbragg » Thu Oct 08, 2015 5:18 am

The timer will be used to control a loop I will need for what I am doing. What is bothering me is I can capture the key press initializing it at startup in this fashion.

But I can't call the same function using the standard xml key binding method
Code: Select all
 <nasal>
        <dash>
            <file>Nasal/dash.nas</file>
        </dash>
    </nasal>


Code: Select all
<input>
        <key n="32">
            <name>Space</name>
            <desc>Test</desc>
            <binding>
                <command>nasal</command>
                <script>
                    dash.keyHandler();
                </script>
            </binding>
        </key>
    </input>

It make no sense, unless I am missing something.

I can't even call a system nasal call
Code: Select all
<input>
        <key n="32">
            <name>Space</name>
            <desc>Test</desc>
            <binding>
                <command>nasal</command>
                <script>
                   gui.popupTip("do something dang-it");
                </script>
            </binding>
        </key>
    </input>


To add insult to injury, I can call call the .nas function using a GUI call.
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby AndersG » Thu Oct 08, 2015 8:05 am

Note that the XML hierarchy for keys is input/keyboard/key...
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Re: Dead Simple Human Powered Aircraft model v1.0

Postby wlbragg » Thu Oct 08, 2015 4:45 pm

AndersG wrote in Thu Oct 08, 2015 8:05 am:Note that the XML hierarchy for keys is input/keyboard/key...

Like I said, "I must be an idiot"!

Thank you!
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