My RC experiments with electric models

Started by wingmanbunty, December 18, 2013, 02:26:57 PM

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wingmanbunty

#150
by Richard Lindberg

Exponential.





This function is more clearly shown in the following graph (...a picture is worth a thousand words...).
This is the 'usual' exponential that is described in your manual—as the graph text says, "...increasing exponential values gives a smaller response for the same stick movement around neutral." For JR, this exponential is called Positive, and you should enter positive values to achieve it. For Futaba and HiTEC, this exponential is called Negative, and you should enter negative values to achieve it. For other manufacturers, please check your manual for the correct inputs.
Note the curve(s)—indeed there is a smaller response around neutral, just like dual rates, but unlike dual rates, full deflection is available near extreme stick positions. Kinda like having your cake and eating it, too...this is why I think exponential is perhaps the most useful of the functions in your computer radio!
Your manual will probably state that values of exponential can range from –100% to +100%. Ignoring, for the moment, which brand of radio we're talking about, what does the 'other' exponential curve look like, and why should you use it (or NOT!)? Check out the following graph. Note the servo response around neutral—for a VERY SMALL stick movement, the servo response is HUGE! This is why you should be very careful to input the correct values (either positive or negative, depending on your radio and the softness/sensitivity desired)!
When would you choose to use this kind of exponential? As the graph text states, perhaps for airplanes that exhibit sluggish response, or for 3-D models, or (so I'm told) for some helicopter tail rotor applications.†
Exponential values are usually assigned as part and parcel of assigning different (dual) rates, and therefore are controlled by the same switches. You can, for instance, set exponential values for one rate (such as the high rate) but not for the other, then compare the response when you fly. (Remember, however, that lower rates don't give you full control authority...!)
There are variations of these functions. One of these is called:
EAT ,SLEEP , FLY

K K Iyer

@wingmanbunty
Glad that you learnt about expo and dual rates.
But why did you make these last two posts?
The manual that comes with the RC usually contains this info.

Also when you post material that is not authored by you, the source should be mentioned.
Regards.

wingmanbunty

i will take care next time sir

i thought it could be helpful to anyone else in the same situation.
EAT ,SLEEP , FLY

wingmanbunty

hello

anybody know which kind of  bond to use for  joining

coro sheet and thermocol
EAT ,SLEEP , FLY

Nithinraj Kotian

hot glue & Araldite clear 5-Minute epoxy   :hatsoff:
Life is Simple Don't Make it Complicated

Swapnil

5-min epoxy works great. While using hot glue, cover the thermocol with clear tape and then apply hot glue to both the surfaces.

rcrcnitesh

thanks wing man bunty sir.
it helped me
Maker | Aeromodeller | Teenager

wingmanbunty

new tow launch glider build

from coro, hd thermo col,steel tube

desire to perform very long distance glide ,and improve myself in airfoil design.

wing 120 cm
length 80 cm
EAT ,SLEEP , FLY

K K Iyer

@wingmanbunty
Good start.
Pl share
Wing area and all up weight.
RC or Free Flight?
Why steel tube?
How is the glide?
How well does it tow?

wingmanbunty

@kk iyer sir
The source of inspiration is your glider  :iagree:
It travel more than 50 feet at 5 feet gentle hand launch  (1:10) but it is no near to the performance of you glider
Wing cord at the centre is 6 " and at the tip is 3" length is 120 cm
(total wight 380 grm ) Nose weight is 200 grm bec wind is blowing hard now a days
No rc,no servo , no motor installed
There is a L hook and I pull it in the air buy kite rope at that time I dcrease the nose weight to 150 grm.
Problems
1. When I tow the glider , glider got released at half the distance I mean 45 degree
I am expecting it to be above my head ie 90 degree
What could be the prob.
2. I build it to understand airfoil shape
 As the length of the wing increases its tendency to bang on one side also increases, sir how to improve it in the construction level
I want to say wing become more sensitive to the turn as length of wing increases.and this turn sometime result into stall .
EAT ,SLEEP , FLY

wingmanbunty

swing wing mechanism glider


material used coro sheet.
bamboo stics
bicycle spoke
rubber band to launch



EAT ,SLEEP , FLY

wingmanbunty

length 32cm
wing 42 cm

EAT ,SLEEP , FLY

wingmanbunty

glider is launched by rubber band  .wing unfold when it reaches to height

good for park flying
EAT ,SLEEP , FLY

K K Iyer

@wingmanbunty,
It may interest you to know that this idea is 84 years old.
This model used to be sold by India's Hobby Centre since over 50 years back.

Good that you are reviving the idea. Wish you success.

http://www.oldwoodtoys.com/american_junior.htm

utkarshg13

I remember I saw this during my last visit to India Hobby Centre at Kolkata.
"If you were born with wings, do every thing you could, for flying."

wingmanbunty

#165
servo installed in eurofighter



https://www.youtube.com/watch?v=r1nLHwc9mZ0&feature=youtu.be

trainer airplane


EAT ,SLEEP , FLY

iwincar

yes KK Iyer I had one brought from India HoBBY CENTRE when I was 12 it was spitfire with a iron weight fixed on its nose for CG
It also had a wing adjustment front of shifted behind would give short or long flight , the balsa wood had some peculiar smell also

wingmanbunty

its recall of childhood memory.


i used to build by card board.and i used to paint it with water color.



i also used to build thermocol glider which is lauched by kite rope .


there is one other in which propeller was powered by rubber band , and propeller used to rotate by the energy stored in the rubber band.i made several of them.
EAT ,SLEEP , FLY

wingmanbunty

trainer crashed, modified wing tip, will it work


My trainer airplane got crashed when I flew in heavy winds before rain, I was performing sharp turns and it got stall   it break in  two parts I had done the repairing and modified its wing tip


EAT ,SLEEP , FLY

shobhit17

Iyer Sir...... That was my first model......
Well I been into aeromodelling since I was in School....  and then been in the air for over 30 years.  Now looking to be back into aeromodelling full time...

wingmanbunty

My first coro build eurofighter was not success because the avionics transmitter perform error in delta configuration
I decided to build simple aileron and elevator  su 30 mki , it fly well but it require more power for aerobatics

Now learning from both my coro model decided to build again the eurofighter with aileron and elevator
This setting work well with my transmitter for power I want to use 8x3.8 size prop with my 1700 kv motor
That will give me 450 to 650 grm of thrust

i know the coro has strength and  performance problem for parkjets biofoam is best but i want to try

I decided to build it what expert think should I go with the plan       :headscratch: :headscratch: :headscratch:
EAT ,SLEEP , FLY

wingmanbunty

what matterial used in this f 22 raptor

wings seem to me in coro
EAT ,SLEEP , FLY

topalle

Sanjay sir has made it entirely from coro...
Amateur photographer ... DIY enthusiast ... Scratch Builder... Student-Innovator

wingmanbunty

@topalle

thanks for the information sir

and thanks to all how reply my pm related to building material of parkjets

As was searching coro build parkjets now it is proven that Coro can be used for building park jets
The only issue is the material is heavy
But the aircrafts build fly very fast
Second the crash resistant behavior of the material
If the model is build form balsa wood or thromocol any kind it will explode at the crash but coro model can handle lots of crash
So for the experimental rc aircrafts coro is a good matrial to chose from
This is a proven design from flite test
http://flitetest.com/articles/ft-22-raptor-build
sir is having  very good at the skill level so they  build and fly it in coro.aircraft also looks very neat and clean .
EAT ,SLEEP , FLY

wingmanbunty

I crash last coro airplane learning aerobatics, but very hardly survive the motor
I am showing you the jugad  and installed it in my next airplane
It become very hard to get back to build new airplane after losing some equipments
Sometime it takes months to get back to flying
EAT ,SLEEP , FLY