Tuesday, October 25, 2011

The Clark Y Airfoil is Ideal for RC Model Aircraft

Complete instructions on how to plot out a Clark Y airfoil Outline of a Clark Y airfoil

Clark Y is the name of an airfoil that is widely used in aircraft design. With its predictable and gentle stall characteristics and flat bottom outline, the Clark Y airfoil is an ideal choice for sport RC model aircraft. I have used the Clark Y airfoil for all my model airplane designs, from the Electro Aviator to the Finch.

See later on in this article for complete instructions on how to plot out a Clark Y airfoil from tabulated ordinates. Drawing up your own airfoil shape is very easy to do. You can use the tabulated ordinate method to draw a Clark Y airfoil by hand, or use TurboCAD for the drafting task. You can then use TurboCAD to draw additional versions of the finished Clark Y wing rib shape for any length wing rib your model aircraft design requires.
Table 1: Ordinates to draw a Clark Y airfoil. All figures are a percentage of rib chord (top line), with percentage of chord upper and lower airfoil points on next two lines


 Selecting an airfoil is one of the most important decisions that a model airplane designer has to make. Airfoils can vary from a complete symmetrical shape, usually used for aerobatic RC models, to a no airfoil at all. The employment of no airfoil, in other words a flat wing, is used only on lightweight electric powered flyers. The flat wing usually lends itself best to smaller aircraft used for indoor 3D flight. With this type of model, the thrust actually exceeds the weight of the aircraft. As a result, the shape of the wing’s airfoil is really not all that critical. A flat wing will not apply for larger or heavier model aircraft, where an airfoil shape must be employed.
Table 2: Percentages from Table 1 are used to determine the upper and lower marks for this example Clark Y airfoil which is ten inches in length
Antique airplanes, incorporating designers’ early knowledge of airplane building techniques and aerodynamics, often had an under cambered airfoil shape. An under cambered airfoil can be captured for lighter weight scale RC model airplanes of antique aircraft. I used the top outline of a Clark Y airfoil for my 1912 Blackburn monoplane wing’s airfoil shape.
Initial plot of upper and lower points for the sample airfoil
As a general rule an under cambered wing cross section does not have enough depth for the strong spars needed for a larger aircraft. To maintain wing strength, the two options are to use a deeper wing section, as available with a Clark Y airfoil, or to employ functional wing to fuselage rigging wires in your model airplane design.



Initial bezier curve outline of the airfoil


The Clark Y airfoil was designed in the early 1920s by Virginius E. Clark. As you can see from the Clark Y ordinates, the airfoil bottom is flat from essentially 20 percent of the chord to the airfoil’s rear end. This flat bottom shape makes for simplified RC model airplane construction, as the wing ribs can be pinned directly onto the building board to guarantee a warp free wing.
Construction lines are removed from airfoil sketch
The Clark Y airfoil is a great choice for the RC model airplane designer. The Clark Y has high camber, which allows for an efficient lift to drag ratio on a typical lightweight RC model. For the benefit of all users of this airfoil, the Clark Y offers predictable and gentle stall characteristics.
Finished Clark Y outline and two examples of a complete wing rig outline
The Clark Y airfoil has a deep mid-section that allows a model airplane designer to add whatever structure and wing spar arrangement that is needed for a particular wing layout. In addition, the generous volume within the Clark Y wing shape allows the placement of other functional equipment such as aileron or flap servos and retractable landing gear.
The tabulated ordinates are easy to use to draw your own airfoil. The top set of figures is the percentage of the chord back from the leading edge of the airfoil. The second line (Upper Mark) is simply the top of the airfoil from a datum line as a percentage of the airfoil chord. The third line (Lower Mark) is the bottom of the airfoil shape, measured from the datum line, as a percentage of the airfoil chord.
Draw with CAD or by hand

For our example of drawing a Clark Y airfoil, I will use an airfoil chord of 10 inches to make the math easy. I used TurboCAD for the drawing, although you can easily draw the airfoil by hand on paper with a pencil and a French curve.
Division lines are drawn back from the airfoil leading edge at 2.5 percent, 5 percent, 10 percent, etc. as shown in the ordinates chart. Next add the calculated upper and lower marks on each division line. I then used TurboCAD’s Bezier curve to join the intersections for the final Clark Y airfoil shape. If you are drawing the Clark Y airfoil by hand, use a French curve to connect the upper and lower marks on the division lines.

19 comments:

  1. Many thanks for the exciting blog posting! I really enjoyed reading it, you are a brilliant writer.  I actually added your blog to my favorites and will look forward for more updates. Great Job, Keep it up...
    remote control plane sydney 

    ReplyDelete
  2. I’m a great fan of your blog; I regularly visit this site to get further details from here.

    Buy Multirotors Online

    ReplyDelete
  3. sir,
    i want to make an ic engine aircraft which could carry maximum payload and could take off and land nicely.. so please could u suggest me how do i design my wings to be ??

    ReplyDelete

  4. mcafee.com/activate registered trademarks, company names, product names and brand names are the property of their respective owners, and mcafee.com/activate disclaims any ownership in such third-party marks. The use of any third party trademarks, logos, or brand names is for informational purposes only, and does not imply an endorsement by mfmcafee.com or vice versa or that such trademark owner has authorized mfmcafee.com to promote its products or services. office.com/setup is an independent support and service provider for the most secure remote technical services for all Office products. Our independent support services offer an instant support for all software related errors in the devices, laptops, desktops and peripherals. We have no link or affiliation with any of the brand or third-party company as we independently offer support service for all the product errors you face while using the Office. If your product is under warranty, then you may also avail our support services for free from manufacturer’s official website office.com/setup. mcafee.com/activate is an independent support and service provider for the most secure remote technical services for all norton products. Our independent support services offer an instant support for all software related errors in the devices, laptops, desktops and peripherals. We have no link or affiliation with any of the brand or third-party company as we independently offer support service for all the product errors you face while using the norton. If your product is under warranty, then you may also avail our support services for free from manufacturer’s official website norton.com/setup.

    ReplyDelete
  5. A decent structure must state to customers or potential customers that your business is proficient; you care about your business; you comprehend what you are doing; and your business is the one that can be trusted to carry out the responsibility right. That is a great deal to pass on with one little realistic picture - yet this is the way significant a logo is to any organization's corporate image. The logo says the majority of this through shading, structure and picture.logo design service

    ReplyDelete
  6. McAfee Antivirus offers great protection against online threats as well as the attack of the unwanted virus in your system. This smart software ensures total protection for your device against security issues. also, to avail the benefits of proper protection. visit on mcafee.com/activate | www.mcafee.com/activate | mcafee.com/activate

    ReplyDelete
  7. Office is one of the biggest, best and the top rated Productivity Software in the market. This just creates a space for alot of errors and warning for the software to have while installing or while running. For more information visit on office.com/setup | www.office.com/setup

    ReplyDelete
  8. Thank you so much for spending time to write this blog article, i must say you are a excellent and talented blogger, I Found This Article To Be Very Informative and Helpful, please keep sharing such amazing blogs I am a Accountant from United States of America, Washington Dc, and I Love to read and Write Blog.
    Some Of My Web Blogs Awesome Blog Post Please Feel Free to Check Out My Blog you will find the process of Norton software installation with step by step instructions and much more.

    Keep Sharing will come back to read more,

    Click to Process

    norton.com/setup download and install
    norton.com/setup enter product key
    www.norton.com/setup
    login.norton.com
    my.norton.com
    norton.com/setup
    norton.com/setup activate
    norton.com/setup install
    norton.com/setup help
    norton.com/setup renewals
    norton.com/enroll product key

    ReplyDelete
  9. I think I have never seen such blogs ever before that has complete things with all details which I want. So kindly update this ever for us.
    www.primevideos.com/mytv
    www.prime.com/mytv
    www.primevideos.com/mytv
    www.hulu.com/activate
    www.primevideos.com/mytv

    ReplyDelete
  10. Thank you so much for giving us such a productive information. This will really help .
    office.com/setup

    ReplyDelete
  11. Primevideo.com/mytv - Do you need to register your viable gadget at amazon? Simply go to the site www.amazon.com/mytv and adhere to the directions to finish the enrollment of your gadget, at that point you can begin getting a charge out of Amazon Prime Instant Video administration for nothing.
    Read more…

    ReplyDelete
  12. Go to amazon mytv login - know best method to www.amazon.com/mytv prime in new device and watch web series. Using primevideo.com mytv enter activation code in your device.primevideo.com/mytv

    ReplyDelete
  13. Amazing work done. Nice website, Love it. Great website.
    ij.start.cannon

    ReplyDelete
  14. Thank you for sharing this post and it is very well told that you can easily understand and get it done. mcafee.com activate McAfee’s Gamer Security will automatically detect that and will optimize its performance according to it. This sure is a great innovative step in the gaming security sector.

    ReplyDelete
  15. So, Is GiftCards.com Legit? The idea of putting your credit card data on a site has never been used before could be stressful. The variety of reviews can make it difficult to know whether the site is authentic or not. We believe that it's legit, but it is far from perfect.
    hbomax.com/tvsignin
    Mcafee.com/activate
    amazon code

    ReplyDelete
  16. The world has enjoyed their Prime membership on larger-screens. www.amazon.com/mytv has made it easy. MyTV App registration is your best option for streaming all of the Amazon Prime shows to your Smart TVs. The above article will solve all your registration, login, verification problems. Now all you have to do is put on your comfy clothes and enjoy the theatre-like experience at home. Log in with your Amazon Prime Login account to access all your favorite web series and original web shows on your smart amazon code
    amazon.com/code
    amazon.com/us/code
    amazon.com/us/code

    ReplyDelete
  17. We already stated that you don’t need any additional contraptions to be successful.target gift card balance
    amazon mytv
    amazon com mytv

    ReplyDelete
  18. Akshi Engineers is among the gearbox manufacturing company in India. We offer quality turnkey solutions for hot rolling mills within your friendly budget. To get a free quote, visit our website.

    ReplyDelete
  19. This comment has been removed by the author.

    ReplyDelete