Hill to Estimate Height |

Slope Flying UMX Radian |

Using the Estes AltiTrak device that I had purchased for computing the apogee of model rocket launches I was able to measure the angle of the face of the slope (22 degrees), no doubt some type of carpentry level could be used as well. Then I measured the length of the slope using a tape measure (39 feet), this would be the length of the hypotenuse of a right triangle which is the basis of trigonometry.

Measuring Face of the Hill - Hypotenuse |

Estes Alti - Trak to Find Slope of Hill |

For myself math skills become rusty because I do not use math enough, I posed the scenario of what I was trying to calculate on model aviation listserve and someone provided an example of the correct trig function to use; the sine function. Sine = Opposite / hypotenuse so the height of the top of the hill would be the opposite side of the right triangle. Rearranging terms the height of Slope =sin(angle)*hypotenuse or =sin(22)*39ft = 0.375*39ft= 14.6ft the height of the slope.

There are other small slopes that I would like to compare to this one as to available lift. It would be interesting to see if there was significantly greater lift from a slope that was 30 feet tall compared to 15 feet. No doubt there are many more variables to the lift than slope height. My guesses to slope height tend to be rather optimistic, this slope I thought was close to 25 feet tall.

Bill Kuhl

http://ideas-inspire.com

**Related Links**

UMX ASK 21 Glider

Slope Soaring UMX Radian

Basic Aerodynamics With a Lesson

Simple Math Tutorial to Go With Lesson

Slope Soaring UMX Radian

Basic Aerodynamics With a Lesson

Simple Math Tutorial to Go With Lesson

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