Welcome, Guest. Please Login or Register
Stick and Tissue Logo
 
  HomeHelpSearchLoginRegister  
 
 
Pages: 1 2 
Send Topic Print
Sillycopter Series (Read 9634 times)
Reply #5 - Nov 22nd, 2014 at 4:59pm

Robert Hudson   Offline
Full Member
I Love YaBB 2.5 AE!

Posts: 129
***
 
I remember making some single-bladed rubber copters many years ago.  Something to revisit perhaps and include Sillycopter innovations.
 

Tissue!

Gesundheit...
IP Logged
 
Reply #4 - Nov 22nd, 2014 at 3:17pm

Kittyfritters   Offline
Senior Member
Stick & Tissue
California

Posts: 647
****
 
So, why the Sillycopter?  Aside from the fact that I wanted to make a cute helicopter, I wanted to make a more stable rubber powered helicopter that was still a simple "Chinese top" type machine, without going to the complications of a powered counter torque rotor or contra-rotating rotors.

Here's an example of how the typical rubber powered helicopter flies.

https://www.youtube.com/watch?v=B-FxNsX0lAg

And, here's a short flight of the Sillycopter.

https://www.youtube.com/watch?v=hHFCfVlh29M

Haven't completely eliminated the torque reaction,(and, probably never will completely) but I think you can see it's a great improvement.  When I get it refined I will publish the plans.
 

Qua sublata omnia praecepta legis
IP Logged
 
Reply #3 - Nov 8th, 2014 at 12:51pm

Kittyfritters   Offline
Senior Member
Stick & Tissue
California

Posts: 647
****
 
Mk III

Experimenting with the Mk II Sillycopter I discovered that the vane in the photo is about the smallest one you can use if you want to keep the angle moderate.  If the angle is too steep you get a downward thrust as well as the counter torque side thrust which makes the copter fly backwards in circles.  Figuring that if I made the "cockpit" area, forward of the motor stick, at an angle to add to the side thrust, essentially turning the entire fuselage into a counter torque rotor, the angles could be made more moderate, I designed the Mk III Sillycopter. 

Except for a couple of minor structural details, I am completely satisfied with this one right off the board.  It flies exactly as predicted.  After a few indoor flights to confirm its characteristics, (My den has a 13-1/2 foot high ceiling.) I took it outside for a test flight with 1000 turns on the motor.  Released in the middle of the street, it flew beautifully, easily clearing the 30 foot Magnolia tree in my parkway strip, but there was just a hint of a breeze that carried it over my house.  It didn't quite make it into the back yard and I did have to get the ladder out to retrieve it from the roof.  I will get a video of it flying, indoors, at the next O.F.F.C. meeting on Wednesday.  Plans will be made available in about 3 months.  (Other projects need attention before January.)

The rotor looks a bit off in the photo because the model is leaning against the background so you are looking slightly up at the rotor.  The pitch of both blades is the same.
« Last Edit: Nov 8th, 2014 at 3:30pm by Kittyfritters »  


Qua sublata omnia praecepta legis
IP Logged
 
Reply #2 - Oct 15th, 2014 at 12:26am

Sky9pilot   Offline
Administrator
Stick & Tissue
Kelso, WA 98626 USA

Posts: 11329
*****
 
Very interesting Copter...is this your own design or are you working from an existing plan?

Rubber powered helicopters are a trip! Cheesy Grin Wink  I shall follow this build with great interest!

Tom
 

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
IP Logged
 
Reply #1 - Oct 14th, 2014 at 2:54pm

Kittyfritters   Offline
Senior Member
Stick & Tissue
California

Posts: 647
****
 
Mk II

Needed to find out if counter torque vane works at all.  This one had removable, adjustable vane.  Photo shows largest vane.  With this vane enough pitch to counter the torque induced a backwards pitching moment.  Made it very obvious that rotor blades needed to be tougher.  Motor stick is bamboo, much stronger than balsa and lighter than basswood.  Power loadings on a rubber powered helicopter are much greater than a similar sized fixed wing model.  Think, you are swinging a very large prop with a very short motor.  More to come.
 


Qua sublata omnia praecepta legis
IP Logged
 
Oct 14th, 2014 at 1:36pm

Kittyfritters   Offline
Senior Member
Stick & Tissue
California

Posts: 647
****
 
Some photos of my Sillycopter series.

MkI

Counter torque vane does not work well...little better than large side area.  Autorotation latch is pointless exercise since the copter always lands with winds on it.  More to come...

 

Qua sublata omnia praecepta legis
IP Logged
 
Pages: 1 2 
Send Topic Print