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I fly a home built quadcopter that is 120g all up weight and hovers at less than 15 percent throttle. I believe maximum thrust in the field is likely in excess of 500g. Needless to say this is a very agile aircraft and easily rockets up into the air and inverses direction etc.

I’m trying to draw some comparisons to this type of vehicle for a blog post I’m writing and I’m curious how this type of power to weight ratio compares to things like race cars, rockets or fighter jets. Eg if my little quadcopter could retain its performance scaled up larger, what would it be like flying it? Or if I could shrink down to the size of a Lego minifig and pilot it directly how would it feel flying it compared to other vehicles. Hoping to get a specific numerical comparison not just a general statement.

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  • $\begingroup$ Well, the latest version of the Pegasus produces 106kN of thrust - a Rolls Royce engine that was used in the Hawker Harrier... You can start researching weights and power to weight ratios for any form of transport you wish - it is only division... $\endgroup$
    – Solar Mike
    Commented Jul 24, 2021 at 19:26
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    $\begingroup$ I understand you can convert power to weight into thrust to weight but not feeling very confident in doing the math myself. Hoping someone who knows this type of these intimately could offer a perspective. $\endgroup$
    – Jeremy Gilbert
    Commented Jul 24, 2021 at 19:48
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    $\begingroup$ @JeremyGilbert actually, not easily without knowing how much air is being accelerated. Also note planes have wings which don't count as thrust but do affect the efficiency. Perhaps it would be easier to compare something like max g-force? $\endgroup$
    – Criticizing Israel not allowed
    Commented Jul 26, 2021 at 16:45
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    $\begingroup$ IMHO these kinds of metrics are useless and don't really tell you anything except for 'sounding cool' (to a layman that is). The math/physics just make a high power to weight ratio much easier to achieve for a smaller model than for a vehicle in real-life (like @niels_nielsen pointed out). I would personally take your project less seriously if you made comparisons like this. $\endgroup$
    – Chris_abc
    Commented Jan 20, 2023 at 8:39

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In general, "model airplanes" have power/weight ratios far greater than their full-size counterparts, which means for example a Piper Cub model with a gas motor in it can climb vertically whereas the real thing cannot. I strongly suspect the same is true for quadcopter drones as well.

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The GEnx turbofan engine has a thrust/weight ratio from 5.15-5.62, according to the Wikipedia page https://en.wikipedia.org/wiki/General_Electric_GEnx. As a cautionary note, please consider the operating condition at which the thrust and power are rated. In other words, where was the power rated in the flight envelope (i.e. take-off, climb, cruise, etc)? What is the ambient condition? How was the weight classified (i.e. dry? wet? with payload?) Also remember that engines are classified with different ratios depending on the application. Jet engines goal is to produce thrust, so thrust to weight is important. However, for a ground-based power turbine or an automotive engine, the shaft horsepower output would be more appropriate to use. Finding figures on UAVs can be difficult, considering their extensive and expanding use in the defense industry. This site is a pretty good collection I've found https://www.militaryfactory.com/aircraft/unmanned-aerial-vehicle-uav.php

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