Folding Park Flyer

[miraclesailor]

Even though it has not flown yet I thought I would share this with you. This project was inspired by Dave Robelen’s Pattern Babe. If you have seen it then you know that this is not it. I had every intention of making one and then woke up in the middle of the night with a different plane in mind. I wanted one to keep in my car at all times. I have a small car so that was going to be quite a feat. What I came up with is a Scimitar design that has folding wings and a profile fuselage. The fuse is about 18 inches long with the prop on it and the wings fold down to 12 inches (wingspan: 24 inches cord:8 inches). It weighs in at 6.4 oz (flying weight) with a two cell 500 mAh Lithium Polymer battery. It is a balsa buildup with some variances. For example I put a piece of EPP foam on the leading edge and the spars are bamboo skewers. I covered the wings with Reynolds Wrap. I was going to cover them in Coverlite but I did not have good luck with it. Ripped it off and started over. I am using a DX-D motor and will turn a 12X8 prop for the first flight. The radio in an MRX-4, ESC is a Pixie-7 programmed for a 6volt cutoff, and 2 HS-55 servos (maybe three later if I like it). I found some felt pens and highlighters for the fuselage. The wing is a friction fit into a slot in the fuselage.

While I was trying to figure out the CG I broke the nose off the fuselage while lightly tossing it in the house…what has my mother always said? I have never made a profile plane before so I did not know to strengthen it there. I did and am satisfied that the reinforcement will last at least one throw. This is a complete experiment. I did not even know what a Scimitar was until I shared the design on this site and was told what I had. I wonder if there is anything new? Folding wings? I will bet…not.

I will fly it when the rain clears here in sunny Southern California. Oh, I can not have clearing winds either.

Later,
Dan

[Dave Robelen]

Hi Dan,
Sorry to hear you broke the nose already. You must have a fair size house to be tossing it around indoors. It looks really neat the way you have decorated it.
Be prepared to enlarge the vertical tail. With that short of a moment arm, the bird is apt to get "squirrely" under power. The Scimitar series generally have a fuselage of sorts to give the vertical tail more moment arm. When you made it into a "wing" you reduced the moment arm of the tail assembly dramatically. The horizontal mode is handled by using a stable airfoil, and forward CG. The directional stability is another matter, since it is a funtion of wing span, area, and the size and moment arm of the vertical tail.
Good luck, Dave