HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 30, 2003, 11:47 AM
Self-taught crash expert
cynewolf's Avatar
Hamilton, Ohio, United States
Joined Jun 2003
211 Posts
Fan-fold experts, lend me your opinions...

I am relatively new to R/C, but I would consider myself in a
transition between beginner and intermediate maybe. Anyhow,
I have been getting the urge to fly a plane with ailerons on it...
so I made a wing with no dihedral (di- or poly- hedral will simply
fight ailerons, right?) and put it on my "mostly-Frog" favorite
little flyer.... sans ailerons for the first test flight! Wing span was
several inches greater than original Frog dihedral wing, so she
had a nice amount of extra lift. However, no dihedral, no
ailerons, NO CONTROL! I am amazed I got the poor bird down
in one piece! I had to muscle that thing, wouldn't level out to
save it's life, and the rudder wasn't all too helpful, but it was all
I had.

Well, now I not only understood how a dihedral wing helps, I had
first hand knowledge of how badly I need one! =]

So, last night a revamp the same wing, cut some ailerons in LAR
fashion, hook them up to a single servo centered under the wing.

Waited all night for the sun to wake up (I was awake, what's it's
problem!?) was at the flying field at the break of dawn. First flight
needed some trimming, banking to the right rather sharply. Not
alot of help from trimming the ailerons, but it seemed OK at first.
Level her out, try my first turn, using ailerons and rudder together
as I thought I should, what a fight! I brought her down, thinking
maybe a need to reverse the channel the ailerons are on. Not a
good choice... crash. Well, I'll link / mix the ailerons - rudder, first
I did it in NOR mode. Bad. Then I did it in REV mode... not TOO
bad, but compared to the control I am used to with elevator /
rudder/ dihedral this stinks! Also have troubles keeping a nice
level craft.

I brough her home, ready to crawl back to my dihedral wing and
beg forgiveness for being unfaithful!

I am wondering if the undercamber wing is a bad combo with the
ailerons... or maybe I had too little travel on the ailerons... they
are supposed to move opposite right? When one is up, one is
down?

Maybe the shape of the wing tips needs some mod?

ANy bright ideas are greatly appreciated! Thanks and have a
great Labor Day weekend all!
cynewolf is offline Find More Posts by cynewolf
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 30, 2003, 11:56 AM
40%, 5% whats the diff?
TeamSME's Avatar
Baltimore Greenbelt, Maryland, United States
Joined Jul 2003
1,341 Posts
When you move the stick to the left the left aileron comes up and the right aileron comes down. Vice versa for right. Dihedral helps a plane get back to it's normal flight path.
TeamSME is offline Find More Posts by TeamSME
Reply With Quote
Old Aug 30, 2003, 12:41 PM
The effect is sadly temporary
Hippo's Avatar
Ann Arbor, Michigan
Joined Oct 2001
1,675 Posts
Cynewolf,

If you're using baked wings (looks like you are) I would taper the wing, so that it has the full chord at the center, and you take an inch off the trailing edge at the tips. This will create washout, and help to improve stability.

Also, yes, ailerons aren't all that effective on an undercambered wing like that, but on my Shark, I found I got the best results mixing 50% rudder with the ailerons.

Like TeamSME said, make sure everything is moving in the right direction. You'll also want some differential if you can make it happen. That is, the aileron that's moving up should move farther than the one that's moving down. If you position your control horns right, this is automatic... Unfortunately, I can't remember which way they need to go for that right now...

Good Luck, Stick with it.
-Dan

P.S. The ailerons will become a lot more effective if you sheet over the bottom of the wing to create a flat bottomed airfoil.
Hippo is offline Find More Posts by Hippo
Reply With Quote
Old Aug 30, 2003, 04:48 PM
Self-taught crash expert
cynewolf's Avatar
Hamilton, Ohio, United States
Joined Jun 2003
211 Posts
Thanks for the ideas

I'll put some more effort into getting this to work...

I guess the bottom line is, if it will end up being LESS responsive
than just rudder / elevator then I won't keep it.

I reshaped the wing, I already just by chance had the differential
set up... not on purpose I assure you.

I don't know about flat bottom... sounds like it'll be something
more than just slapping a sheet of fan fold on... maybe some
split F3?

Thanks again!
cynewolf is offline Find More Posts by cynewolf
Reply With Quote
Old Aug 30, 2003, 05:18 PM
The effect is sadly temporary
Hippo's Avatar
Ann Arbor, Michigan
Joined Oct 2001
1,675 Posts
It could be that simple

A sheet of fanfold beveled at the edges to fit nicely up into the bottom would work nicely. You could also use saran wrap or something to cover the bottom. The foam sheet will add a little weight, but it will really reduce drag, so you'll probably come out even.

-Dan
Hippo is offline Find More Posts by Hippo
Reply With Quote
Old Aug 30, 2003, 08:14 PM
Foam rules
Thatovalguy's Avatar
HdG Md.
Joined Jan 2003
4,914 Posts
With a undercamber you do need the up aileron to have more angle than the down aileron. Being the down aileron creates more drag and will cause the plane to yah the wrong direction in turns. I have a few undercamber planes in the stable that are vary aerobatic on elevator and ailerons, One is my Fan fold fun jet 75 and that plane is a real blast to fly. As far as coupling rudder and ailerons, I never have done it or needed it sept on 1/4 scalers that I have.
Thatovalguy is offline Find More Posts by Thatovalguy
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Lend me your pictures.... portfoxdesign Thermal 4 Feb 03, 2005 10:19 PM
XP-4 experts lend me your knowledge Lightnin Hand Launch 30 Jan 09, 2005 11:24 PM
Slow Stick Experts, Lend me Your Ears KsFlyer Parkflyers 11 Jul 23, 2003 06:25 AM
Slow Stick Owners, Lend me your ears :) KsFlyer Parkflyers 19 Nov 17, 2002 12:37 PM
Help..... Fan Fold Experts! hoppy Foamies (Kits) 8 Jan 27, 2002 04:45 PM