Einzpfeil (oz12553)

About this Plan

Einzpfeil (Single Arrow). Radio control sport model for electric power with 70mm ducted fan.

Quote: "Steve, the Einzpfeil is the most successful and easiest to fly of all my flat jets. 27 in WS with a 70mm fan. It can be built in a day."

Direct submission to Outerzone.

Update 24/03/2021: Added article from FlugModell Apr 2021, thanks to Charlie. Note this is retrospective, the Einzpfeil plan was published first on Outerzone, and the printed article is later.

Quote: "I'm not one to toot his own horn, but the events of the last few months prompt me to share this with y'all. It started with a middle school teacher in Cologne, Germany that had scaled down one of my flat jets and converted it to a catapult launched glider. He sent me a video of his kids flinging the thing into the air on the school soccer field.....I was both amazed and gratified to see kids actually out playing, and not staring at their phone....One thing led to another, and FlugModell Magazine ended up featuring my little airplane in this months issue..Enjoy"

Quote: The Einzpfeil - The Rocket From Memphis. Why go far away when the good stuff is so close? Because there are also great things in the distance, for example the Delta Einzpfeil - it comes from overseas. FlugModell author Thomas Buchwald liked the model so much that he contacted the designer and one thing led to another.

Memphis in the US state of Tennessee is not only the epicenter of rock n roll, it is also home to creative model aircraft designers. One of them is Charlie Fite, a retired engineer, pilot and model airplane pilot by passion. His designs shine with minimalist construction, excellent flight characteristics and very interesting flight patterns. You can see them in the model flight forum RC-Groups: https://www.rcgroups.com/forums/member.php?u=451376.
Charlie's username here is Old_Pilot. There is also a Youtube channel from him: https://www.youtube.com/channel/UCzeGdsL-ZSMY_1K8E09zVXQ/videos.

Charlie has already successfully built and flown the single arrow presented here invarious sizes. For FlugModell he drew a version with 610 mm wingspan for 50 to 64mm diameter impellers and we built and flew it.

Concept: Charlie's idea was to build a ground-launchable impeller model with maximum top speed and minimum landing speed. A simple design with as few parts as possible was also in the specifications. He was inspired by MBB's Lampyridae stealth study from the 1980s. This influence is most evident in the triangular fuselage cross-section.

The model is made of 6-mm Depron, the wing has a Kline-Fogleman 2 airfoil and is reinforced with a CFRP tube or flat section. Ground takeoff capability is provided by two skids under the wing.

The model is designed to use a minimal number of components to create a lightweight yet strong structure. And the whole thing looks good, too.

Equipment: Suitable for propulsion are impellers with 50 to 64 mm diameter, powered by a LiPo in 3s version with 1,600 mAh or a 4s battery with 2,200 mAh capacity. Our model flies with a 50 mm impeller from FMS, 4s-LiPo with 1,600 mAh and a 45 A regulator. Only two servos from the 9- to 12-g class are needed. The transmitter only needs to have a delta mix function.

Since the whole model consists of only 13 parts, construction is easy and quick. You can tell that the parts were designed by an engineer and carefully refined - a minimum of material and build time is used to produce a strong and lightweight airframe.

Charlie Fite builds his models from Elmer's Foam, which is a paper-backed rigid foam. As Europeans, we have the advantage over our American model aviation friends of being able to easily obtain Depron, which makes the model much lighter. However, there are only a few differences in construction between the two materials. Here I describe the construction from Depron..."

Supplementary file notes

Article.

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