Go Back  RCU Forums > RC Airplanes > Aerodynamics
Reload this Page >

WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

Notices
Aerodynamics Discuss the physics of flight revolving around the aerodynamics and design of aircraft.

WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

Old 01-09-2008, 04:52 PM
  #1  
speed lover
Senior Member
Thread Starter
 
Join Date: May 2006
Location: , UNITED KINGDOM
Posts: 242
Likes: 0
Received 0 Likes on 0 Posts
Default WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

What I would love to know would be if there is a calculation for lift. Is there a calculation for how much lift you can get for any given wingspan and chord and root and wing area with also drag factor. The reason is I want to design and build something very specific and unique can anyone help
Old 01-09-2008, 09:03 PM
  #2  
highhorse
My Feedback: (2)
 
highhorse's Avatar
 
Join Date: Nov 2006
Location: Memphis, TN
Posts: 2,564
Received 93 Likes on 49 Posts
Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

i've seen links in prev threads to programs u need.......
Old 01-10-2008, 10:18 AM
  #3  
BMatthews
 
BMatthews's Avatar
 
Join Date: Oct 2002
Location: Chilliwack, BC, CANADA
Posts: 12,425
Likes: 0
Received 22 Likes on 19 Posts
Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

To do a complete analysis of all the stuff there's a number of formulas to run your material through. Part of the plan is also your airfoil choice. Depending on the size and speed of your model this will determine the maximum lift coefficient that you can operate at before the wing stalls. For example the SAE heavy lift models can operate up close to a Cl of 2 while a light indoor model may only be able to get to 1 or so. This is largely due to the reynolds number effect. So keep that in mind if you are wanting to operate in one of the more extreme aspects.

I don't keep the formulas handy but I know that others have dug them up from web searches. Try key words like "aerodynamic lift drag calculation" or "wing lift drag calculation" and I'll bet you find them soon enough.

For a quick test run your planned wing size through Foilsim (google for it from the NASA site) and alter the one airfoil they give you to be the planned camber and thickness and then input the wing size and expected weight of your model. Then alter the angle (angle of attack) and speed until your "model" is running around a Cl of 1. Then switch to the lift readout and see how many lbs of lift you have.
Old 01-10-2008, 05:24 PM
  #4  
speed lover
Senior Member
Thread Starter
 
Join Date: May 2006
Location: , UNITED KINGDOM
Posts: 242
Likes: 0
Received 0 Likes on 0 Posts
Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

Thanks for some feedback I plan on a weight of roughly 6 ¼ to 6 ½ lbs and for power a 61 mds rear port with a custom exhaust and after market carb what I want to try to do is build an elliptical wing that will not make my plane float at take off and landing. Like some straight wing models ie pulse xt. And others alike. I also want to try to get the wing as thin as possible for a given stall speed what I mean is instead of picking a wingspan pick a lift amount that will fly my plane at the given stall speed and then try to retain the as little root as possible by increasing wing area through span an chord if this makes sense.
Old 01-10-2008, 05:30 PM
  #5  
da Rock
Senior Member
 
Join Date: Oct 2005
Location: Near Pfafftown NC
Posts: 11,517
Likes: 0
Received 2 Likes on 2 Posts
Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

You might also look through the sticky at the top of this forum. It's Sticky: Aerodynamic Tools, Calculators, and Test Links and I think it was originally started by someone who often posts here. Someone well respected in the community.
Old 01-10-2008, 05:42 PM
  #6  
speed lover
Senior Member
Thread Starter
 
Join Date: May 2006
Location: , UNITED KINGDOM
Posts: 242
Likes: 0
Received 0 Likes on 0 Posts
Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

Im not very familiar with forums and don’t realy know what you mean by at the top of this forum could you put a link or an address I can copy and paste.
Old 01-11-2008, 09:54 AM
  #7  
Flying freak
Senior Member
 
Join Date: Jun 2006
Location: granby, QC, CANADA
Posts: 1,407
Likes: 0
Received 0 Likes on 0 Posts
Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF


ORIGINAL: speed lover

Im not very familiar with forums and don’t realy know what you mean by at the top of this forum could you put a link or an address I can copy and paste.
To get here you had to get to the section called "Aerodynamics" when you got to tha page there were a bunch threads and you posted one (this one) at the top of the forum theres a section called "Aerodynamic tools, calculators and test links"

Direct link = http://www.rcuniverse.com/forum/m_2867994/tm.htm
Old 01-11-2008, 10:54 AM
  #8  
BMatthews
 
BMatthews's Avatar
 
Join Date: Oct 2002
Location: Chilliwack, BC, CANADA
Posts: 12,425
Likes: 0
Received 22 Likes on 19 Posts
Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

Speed lover, your idea for decreasing the float is flawed. It's not having a thin wing that reduces the float. It's from the airfoil's camber amount and the wing loading. For the style of model you're talking about the airfoil would have a relatively thin airfoil anyway so that isn't a real avenue regardless. The other factor is wing loading. If you make the loading high enough it may slow down the float on landing but mostly it'll just make it so the model has to fly faster to stay in the air and make it harder to land.

Besides I've seen lots of references to the formula 1 racers with thin wings and higher loadings float on landing due to how clean and efficient they fly.

Truly the only two ways to steepen the glide slope for landings are to use flaps or airbrakes and to learn to fly the model more like a real plane. In full sized aviation no pilot that wants to survive long would EVER dive their craft in for a landing like us model guys do. They set up a slow nose up attitude way out and use the drag from the near stall flight to help establish the glide slope. Combine that with some flaps or other drag device and even a lightly loaded slow flying model will settle in very predictably.
Old 01-13-2008, 03:32 PM
  #9  
Craig-RCU
Senior Member
 
Craig-RCU's Avatar
 
Join Date: Jan 2002
Location: minneapolis, MN
Posts: 645
Likes: 0
Received 0 Likes on 0 Posts
Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

If you don't mind a slower top speed, there is a third way to steepen a glide slope. Use a lower pitch, higher diameter prop. It will give a better air-brake effect than a higher pitch, lower diameter prop. Maybe that fits under the "air-brake" category mentioned above. If you have to input down elevator to dive toward the runway on final approach, you are not flying near the stall speed and are too fast to attempt a landing without "float." If you are set up properly and at the right airspeed for final, the plane will settle down toward the runway naturally. Practice flying near the stall speed at high altitude so that you are not surprised by any tip stall tendencies that the aircraft may have and get used to the more sluggish control response at slow speeds. If there is a wind, I like to practice slow flight by heading into the wind and trying to achieve zero ground speed. It's just a fun challenge to explore the slow end of an aircraft's flight envelope and I've found it really helps me with landings because it teaches me to gage how close I am to the stall speed by noticing how much elevator and throttle I need to hold altitude near the stall.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.