Parasite Drag Force Explained

[@my_dear_friend_]

I will be using your videos in my afterschool model airplane club. Thank you for making them!

[@robinkock9435]

All the graphics are great and really add to the video!

[@xayord9818]

This channel is helpful.❤

[@jurgenhelgen212]

My father presents your videos in airplane modeling classes. 🤗 The students are very happy with your easy and simple explanations to understand. 😉 Thank you for your work in teaching ! 😁 👍 😉 Best regards ! 🙋‍♂️ J H 🇩🇰 JOSS 🇦🇷

[@Jetstreamer0]

Should you expect the steady glide speed to be the same for both gliders? The optimum glide speed depends on the zero-lift drag coefficient, and is proportional to 1/(CD0^0.25). Therefore, using the same elastic launch energy for both aircraft may not be the best approach. Your goal is to achieve the exact steady glide speed in both cases, so as to not launch one (or both) airplane(s) on a phugoidal flight path.

[@DesignYourOwnAirplanes-xd6lz]

Yes, you are correct that increasing the zero-lift drag coefficient decreases the ideal glide speed. I found that to get the maximum flight distance with the non-streamlined glider I had to launch it slightly slower than the streamlined glider.

[@Jetstreamer0]

@@DesignYourOwnAirplanes-xd6lz Interesting! Thanks!

[@JCAtkeson3]

So sometimes area is cross sectional and sometimes not? What about planes where wing and fuselage are the same thing, like a delta wing?

[@DesignYourOwnAirplanes-xd6lz]

For the drag force created by the wing, the area is chosen to be the planform area since the frontal area changes a lot as you change the angle of attack. For other parts like the fuselage, it would be the cross sectional area. Area where the wing and fuselage overlap is usually included in the wing area.

[@RobFeldkamp]

Planform is actually crass-sectional from straight above. Which would apply when a aircraft flies parallel to the airflow (directly into the wind, not descending).

[@ash2embers]

will you be teaching about rc airplanes in the future?

[@DesignYourOwnAirplanes-xd6lz]

I still have several more glider videos planned, but I’ve been considering it.

[@jurgenhelgen212]

​@@DesignYourOwnAirplanes-xd6lz : Please continue with videos of free flight gliders ! 😊 No one ever explains as well as you. 👍 There are many other channels about RC models but none teach about free flight gliders. 🤗 👍 😁 Best regards ! 🙋‍♂️ J H 🇩🇰

[@michaelmcgovern8110]

Thanks!