Let’s say I require 100Hp as stated by my calculations of Thrust for an aircraft-
When finding a power plant for this, would it be better to use a power plant with more Hp or exactly that 100Hp please?
I thought it would be better to use more?
2 Answers
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If your calculations are conservative, and you're sure that 100 hp is the right amount of power for your airplane's mission, then use an engine that you are sure will provide 100 hp under the conditions (temperature, pressure) that you assumed in your calculations.
If you use an engine with more power, it will very likely be heavier and use more fuel than you originally assumed, leading to increased overall mass, requiring in turn more power, stronger structure etc.
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More is better:
You'll have reserve power - engine power of standard engines reduces with altitude, no need to use a turbocharger
There will be a bit of a margin for calculation inaccuracies. It's only a calculation, only wind tunnel tests and flight tests will determine the power requirement.
