Wing and servo loadings.  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       

All Forums >> RC Airplanes >> RC Gliders, Sailplanes and Slope Soaring >> Wing and servo loadings.
Page: [1]

Login
Message << Older Topic   Newer Topic >>
Wing and servo loadings. - 1/4/2003 9:08:16 PM   
Brokie


 

Posts: 11
Joined: 12/12/2002
From: KZN, South Africa
Status: offline 		I have recently rebuilt a 3.2m Multiplex Fiesta SF and have used an online W/L calculator that yields wing cube loading figure for this completed model of around 5.2. The same calculator recommends that gliders should be less than 4. Is this something that should concern me prior to my maiden flight? The calculator I used is at:
[URL=http://www.electric-flight.org.uk/data/wcl.htm][/URL]

I have also just purchased a 4m scale Discus and am becoming increasingly concerned that the JR 331 servos to be used are not going to cut the mustard torque wise. I have used online calculators but am unable to provide the maximum speed figures required! The 331's have 42.2oz/in of torque at 4.8v and are about the only servos I can fit in the wing. Also the fully flying stab has an area of 10 square dm (140 sq/in) and the torque figures required seem daunting at the least...

I have recently started flying again after a 15 year layoff and am horrified by just how technical this brilliant sport seems to have become!
       Post #: 1

Wing and servo loadings. - 1/5/2003 1:45:27 AM   
Ollie


 

Posts: 958
Joined: 12/8/2001
From: Punta Gorda, FL
Status: offline 		Stop worrying! The all moving stab will have zero torque load on the servo if the pivot line goes through the aerodynamic center of the stab because it is aerodynamically balanced. Don't worry about the torque load on the ailerons. the load goes up as the square of the airspeed but so does the aileron response. The servos that fit in the wing will provide all the roll response you would want. If you should stall the aileron servos momentarily at high speed you won't hurt anything. The critical loads are on flaps and rudder in poor landings when they drag on the ground. Always retract flaps the instant before touch down and try to avoid ground loops which might damage the rudder servo. Also don't deploy full flaps at high speed. Pull out gradually first and slow down before deploying full flaps. That's all you have to worry about.

_____________________________

Regards, Ollie

(in reply to Brokie)
       Post #: 2

Wing and servo loadings. - 1/5/2003 1:59:24 PM   
Brokie


 

Posts: 11
Joined: 12/12/2002
From: KZN, South Africa
Status: offline 		Ollie!

Thanks for allaying my paranoia! Any feedback on the wing loading issue? I can't go any lower than 80oz on the all up weight of the Fiesta and this yields a wing loading way above the "desirable" 4 wing cube loading figure...

In any case it's great fo you to take the time to answer all these inane questions from around the world! Much obliged.

(in reply to Brokie)
       Post #: 3

Wing and servo loadings. - 1/5/2003 3:01:42 PM   
Ollie


 

Posts: 958
Joined: 12/8/2001
From: Punta Gorda, FL
Status: offline 		The relatively high wing loading will affect the type of thermals you can work. It will be very difficult to work small, weak low altitude lift under 50 to 100 feet. Above that altitude, the thermals will have widened and strengthened to the point where it will be much easier to work them. Launch as high as you can and try to determine where the lift is before you get too low.

The soaring birds have much greater wing loading that yours and they do just fine. You may have noticed that the soaring birds do most of their flapping at low altitudes and very seldom flap at high altitudes.

_____________________________

Regards, Ollie

(in reply to Brokie)
       Post #: 4

Wing and servo loadings. - 1/5/2003 3:54:25 PM   
Brokie


 

Posts: 11
Joined: 12/12/2002
From: KZN, South Africa
Status: offline 		Thanks Ollie, may all your thermals be "fat ones".

(in reply to Brokie)
       Post #: 5

RE: Wing and servo loadings. - 4/8/2007 3:52:20 AM   
Bastoune


 

Posts: 3
Joined: 3/28/2007
From: , KS, USA
Status: offline 		Brokie,

I am in a similar boat as you are. I am in the process of updating a Fiesta SF that I have not flown for the last 15 years. Unfortunately, I can't find the drawing with the CG location. Could you help me out?

Thanks,

Bastoune

(in reply to Brokie)
       Post #: 6

RE: Wing and servo loadings. - 4/8/2007 9:57:39 AM   
jooNorway


 

Posts: 758
Joined: 12/23/2004
From: Naersnes, NORWAY
Status: offline 		Have you checked the Hitec HS-125 or 5125 servoes? They are thin and easy to mount in tiny wings. I use them even in 4-meter acro scaleplanes.

(in reply to Bastoune)
       Post #: 7

Page:   [1]
All Forums >> RC Airplanes >> RC Gliders, Sailplanes and Slope Soaring >> Wing and servo loadings.
Page: [1]





Jump to:


Google 



Search | Marketplace | Event Calendar | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

Photo Gallery | Member Video Posts | RCU Video Gallery | Instructor Search | Field|Track|Marina Search

Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

SITE MAP!   : :   FORUM RULES

© 2001 - 2007 24-7 RC, LLC, all rights reserved.

Charities we support that also need your help
Yorkie Rescue | Humane Society | ASPCA | Crohn's-Colitis America

Kaango.com Classifieds

0.594RCU2