Cosine Functions in Kite Physics

See my reply about moving the topic here: Questions and complaints about moderation.

I was expecting a reference from the kite domain, at the very least from aerospace or a related field…


Do not be surprised to see AWE terms-of-art first emerge on our Forums. “AWE” itself emerged on the Old Forum, and many other terms. We know who and when these terms first appeared, like Dave Lang coining “flygen” in a Drachen Foundation Newsletter.

Consider Antenna Design cosine-gain usage as naturally applicable to Aerospace Design, without controversy. What better dynamic for introducing new terms in AWE is there, than to encourage users to do so?

“cosine gain” as a term might make sense in a universe where in all planets that had an atmosphere, the energy available in the atmosphere as a function of density and wind speed only ever increases the higher you go. In our universe, that’s not the case. There is not always more energy available at 200 kilometers up than there is at 0.5 kilometers up.

What you do in our present universe is to measure the wind speeds at different altitudes and design your system to target a favorable and achievable altitude, keeping in mind our current understanding of “cosine loss”.

What you are trying to get at is better said by just saying: look at the wind measurements at different altitudes and try to target the altitude where the wind speed is favorable currently or has been over a period of time.

If you want to introduce a new term, do your homework and quantify it, qualify it, and support it with empirical and theoretical data.

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On this planet “cosine gain” makes perfect sense to me. Its no scientific law, just a term of art, just like “cosine loss”, which is no law either.

This is more about an anonymous authority abusing moderation powers than an actual “scrapyard” topic. If we knew who you were, perhaps we could judge better what’s going on. Perhaps you are underage or have some other weird motive to moderate crudely from anonymity. Cosine gain usage as such is just a small part of the wonderful kite cosine math-physics topic, but it all got put in scrap regardless, and only you know who did that.

The KAP usage example stands as a cosine gain case, given a high flying angle is so desirable. I have both observed and practiced KAP, with pros. Ask a KAP pro:

“The kite has a high flying angle, allowing me to maneuver in tight spaces.”

Having reviewed trigonometry, the only recognized Laws are Law of Cosines and Lambert’s Cosine Law. Neither is violated by either “cosine loss” or “cosine gain” terms of art. The KAP vs power-kite cosine issue is covered under trigonometric identities, as reciprocal (ie. sec theta) cases. There is no conflict in using cosine “loss” or “gain” in context, as standard descriptors.

No one commenting on the cosine subject has done the homework better than this. Relegating proper kite cosine physics discussion to Scrapyard is the poor-homework decision.