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Forces in a RC Plane

ananas1301

Crazy flyer/crasher :D
#1
Hey guys,

I have to do a investigation at school using my rc planes to find out about different forces acting on a rc plane.

How many G´s are there in a 180° turn ...

I will be doing that very soon anyway but I thought instead of having me trying to explain any of my work and fail at my explanations, Flitetest could do a nice episode about this which wouldn´t be only educational but funny as well.

I thought of using accelerometers there and then look at what forces are excerted in different maneouvers.
I´ll let you know how I will be doing this in a thread maybe if there is a lot of interest shown and not a episode coming up.
 

pgerts

Old age member
Mentor
#2
That should really be interesting to know. Most model pilots have lost a plane because of to much up elevator after a "high speed" dive.
Anas, why cant you do some calculations based on the worlds fastest dynamnic slope soarer - it is almost a round path.
http://k2bs.org.tw/modules/mod_wdbanners/hello.php?html138
You can try to time some laps and calculate the lap time together with the speed and find out the Acceleration forces.
 

ananas1301

Crazy flyer/crasher :D
#3
You know you are speaking with the right person there!

In a circular motion you have to apply a constant acceleration for a constant velocity!

The acceleration is always only for a short time going tangetially to the circle. However due to your elevator input you do fly a circle and the direction (vector) if the acceleration changes but its value stays constant! This gives you the constant velocity.

Now I cant really see how those dynamic soarers can increase there velocity! The power has to come from somewhere.
I am either thinking of it being due to the gravitational force or due to winds at a slope. Both sound reasonable at the moment!



Btw: Does anyone know where to get some kind of "thing" porbably like a data logger that can record the accelerations during a flight with an accelerometer and save that on a small chip. It would be nice to have stuff like current and voltage there as well (GPS as well if possible but not necessarily if it gets too expensive) to make the evalutation of the recorded flight easier and maybe get a readout on google maps or so. Any ideas for that? Or maybe a board that I would need to solder for my self?
 

pgerts

Old age member
Mentor
#4
..
Btw: Does anyone know where to get some kind of "thing" porbably like a data logger..
Dont you get offers to buy "science" or sports magazines with "gifts" the of a value ten times what you pay?
I sometimes find interest in trying those garbage toys.....
This little GPS is the size of a "key ring camera" and can be placed in most model planes.
As you say "it is a poorably datalogger" ;-) The included software interacts with Google Maps and has one use as a "photo tagger".

 

ananas1301

Crazy flyer/crasher :D
#5
Dont you get offers to buy "science" or sports magazines with "gifts" the of a value ten times what you pay?
I dont get that what you just said:

Do you mean that I sometimes get offered to get a toy for only a fractional amount of money with a magazine or so ?
 

ananas1301

Crazy flyer/crasher :D
#6
Hey guys!

I made a bit of research about exactly what data I would need.
Firstly of course some kind of accelerometer that would measures the G Force (best would be in all 3-axes)
Secondly I´d need a GPS module that I can image into Google Earth and then compare where which forces were made.
Then a good camera to record the flight itself so I see which maneouver has which forces in average.
Force Module that goes in all three axes.

Just one little question. They sell two different G Force "measurerer" One that goes up to 7 G and the other one up to 38 G

I can hardly imagine the force being close to 15G at all but I am actually not so sure about the 7G. Could I get over the limit with my Parkzone Extra 300? I think I will be using this in my Event 3D anyway as I want to look at maneouvers and with my Extra I cant really fly controlled maneouvers.

Any ideas of other brands or something similar? Also this Eagle Tree kit is quite expensive so I would have to look if the school could support me in that part financially.
 

ananas1301

Crazy flyer/crasher :D
#7
Hey guys,

So school doesn´t really like the idea of supporting this with some money as I don´t have that much, so I think I have to come up with something myself.

What I thought is trying to get something built and soldered up myself maybe using a small processor if that is possible.
I found this 3 axis accelerometer : 3-axis accelerometer

The problem is that I don´t know how to use it. It will need some kind of proccessor I think that needs to be then programmed to somehow save them on some kind of memory. I have no clue what this is getting me into but I am very interested in stuff I2C but I don´t know ANYTHING about that. Anyone know how to tackle this or giving me a rough information about what I2C is all about? Reading that up in other forums if very hard for me right now.