Video on ‘Parasol’ Structures 101


Today I received a number of questions asking for a bit of clarification on last nights Pietenpol story. In that story I tried to explain some of the planes issues.


 If you are real new to aviation, a ‘Parasol’ is an airplane configured to look like a biplane without lower wings.  Just after WWI, this was the configuration of choice for front line combat fighters. It persisted into the 1920s, and they were the bridge between biplanes and cabin monoplanes. The most famous one today is the 90 year old Pietenpol Aircamper, but over the years, there have been a number of classic homebuilts with this configuration, and some factory built beauties like the Fairchild 22.


In the interest of sharing some info which all Piet builders should understand, , I made a quick video using a ugly balsa representation of a parasol. The esthetics shouldn’t deter anyone from understanding the concepts.




Note, I was tired when I shot this, I did it in one take, and without any kind of a script. I just had a phone call where I was explaining the difference between compression and column bending to a builder who was asking about jury struts. Twice in the video I mistakenly say column bending instead of compressive load. Just ignore it, thanks.


If you have any comments or questions on the video, please share them here. If you have not yet, please subscribe to the Youtube channel. Having 1,000 subscribers will allow us to put links to stories directly in the video comments.





About William Wynne
I have been continuously building, testing and flying Corvair engines since 1989. Information, parts and components that we developed and tested are now flying on several hundred Corvair powered aircraft. I earned a Bachelor of Science in Professional Aeronautics and an A&P license from Embry-Riddle Aeronautical University, and have a proven 20 year track record of effectively teaching homebuilders how to create and fly their own Corvair powered planes. Much of this is chronicled at and in more than 50 magazine articles.

8 Responses to Video on ‘Parasol’ Structures 101

  1. Dave Hoehn says:

    This video is excellent! Your explanations are accurate and easily understood.


    • I screwed up a few words, but the concepts are correct and valid. I don’t like watching myself on video, so I just do the takes in sequence, and often don’t notice I goofed up some thing small until it comes back from Ken edited.

      • Dave Hoehn says:

        It is better to notice the mistakes after the fact, I frequently find myself composing what I want to say in my mind, dumping it to my mouth to be said, and while it is being said, I start re-thinking it and find a better way to say what I want, and then change everything in mid-sentence. The result is usually a garbled mess.

  2. scott thatcher says:

    Very impressive demonstration of the Piet’s and other parasol structures. Thanks.

  3. Mark Chouinard says:

    Great explanation William. Gives me renewed appreciation of the design and increased confidence in my completed work.

  4. Doug Wright says:

    That was excellent, William.

  5. Robert Sackmann says:

    Excellent video.

  6. Dan Branstrom says:

    The video does a great job of showing the various forces that a wing generates on the fuselage. I had never considered the twisting forces on the vertical axis before. Thank you.

    I spent time trying to visualize all of the forces on your previous commentary on the Pietenpol. This video, in spite of the misstatements, makes them very clear. Thank you.

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