Apache24s: A Tale of Two Propellers (Science Olympiad FLIGHT)

We all love Ikara symmetric propellers. They fly very well, esp. after pitch is trued up and tuned to a specific airplane. Q is, can a custom-built propeller outrun Ikara? Check this video out!
Using Apache24s prototype (See my other video for Apache24s story), I first performed a baseline confirmation with a stock Ikara 24cm dia. 32 degree pitch propeller. As shown in the left panel of the video, Ikara propeller pulled Apache24s for two minutes comfortably. This long-tail high-lift no-tip-plate no-frills design is solid and easy to trim. Then, using the same airplane and same 3/32" rubber band, I tried out a new 33cm dia. custom-built propeller. As expected, this big propeller turned slower than Ikara, and flew Appache24s for 2min and 20s, slowly and smoothly. I am happy. More custom-built propellers are on the workbench. More rubber bands to try out, too. :-)
Many things can be observed in this side-by-side comparison video. Watch the two flights for differences in airplane speed, nose-up angle, propeller rpm, etc., during different flight phases. For one thing, the flight with the custom-built propeller has a lower speed after take-off. The asymmetric "flaring" propeller kept the speed consistent throughout the whole flight. Slower speed means less energy is wasted in countering excessive profile drag, which is proportional to speed squared!! Slower speed also makes the airplane looks better in the air. :-) Note that both flights slowed down to about the same landing speed, as they should.
Building propeller is straight forward. Check out links below for building instructions, the propeller mold program, as well as other 3d printable gadgets. Feel free to comment below if there is any question I can help with.
Another note. 33cm dia. propeller on Apache24s won't fit into Div. C's measurement box. Although it flew nicely in the video, it is too big a propeller to pass Science Olympiad's box constraint. :-O Like many things on our SO airplanes, one size does not fit all anyway. Need to build a smaller, ~27cm dia., flaring propeller to fit Apache24s. More propeller molds to build. More fun to fly. Stay tuned. :-)
Like, share, and subscribe! Cheers!
-AeroMartin
Watch 15 Apache24s flying at: (Full size design plan and building instruction are available.)
• TheLittleAirplane - So...
Build Your Own Propellers:
• Build Your Own Propell...
Apache24c2 - Another Unorthodox Science Olympiad 2024 Div. C Design
• Apache24c2 - A Tribute...
Apache23, A Simple and Unorthodox Design:
• Apache23 - An Unorthod...
Check out my Propeller Mold Program and other SO FLIGHT related 3d printable tools at:
www.thingivers...
Music Credit: Motivational Epic Music / Inspiring Cinematic Background Music by SoulProdMusic
pixabay.com/mu...

[@FreeFlightDigest]

Fantastic Video Aero Martin!

[@aeromartin1533]

Thank you! I'm happy to hear you feel that way. That means a lot coming from you. You guys are truly amazing. EVERYONE, if you have not, please visit National Free Flight Society's channel for many more fantastic SO videos. www.youtube.com/@FreeFlightDigest/playlists 👍

[@collinmccallum]

amazing!

[@aeromartin1533]

Thank you, I am happy to hear you feel that way! Many brilliant students are working hard on this event. I am sure more amazing things are coming. Cheers! 🙂