A Performance Calculator for Your Airplane

Benchmark allows you to model the performance of an engine, a propeller and an airplane, then 'fly' the airplane at any flight condition to see how fast it will fly, or how many miles per gallon you will get. Calculate the power of the engine. Watch what happens when you change the design of the propeller. Try out different engine and propeller combinations in your airplane. Print miles-per-gallon charts for the flight manual of your airplane, not a factory-average machine.

Benchmark allows you to get to know your engine, propeller and airplane in ways that have never been possible before, to understand the power and fuel consumption curves of the engine with a degree of accuracy that is unheard of. With Benchmark, our collective understanding of engines, propellers and airplane will never be the same.

Benchmark handles all of the standard calculations used in performance flight testing and analysis—a specialized type of aeronautical engineering used by aircraft manufacturers to conduct performance flight tests, analyze the flight data, model the performance of the airplane and finally produce performance charts for the flight manual for the airplane. It is the only program of its type in the world and in a few seconds Benchmark handles all of the calculations that have previously required months of engineering work and analysis.

The normal flight test regime involves serious, careful work to model the performance of the airplane. But once you have modeled a design—Falco, Bonanza, Mooney, etc.—you can then use one airplane as a base for the performance modeling of another plane of the same type. We have Karl Hansen's 160 hp Falco modeled, and it's an exceptionally fast machine. But your Falco may have a 180 hp engine, a different propeller and may not be as fast. With Benchmark, you can 'save as' to create a separate airplane file, change the engine and propeller and then add or subtract drag to match the performance of your airplane. This done, you can calculate the performance of your airplane at any flight condition and produce your own performance flight manual charts.

Thus Benchmark is an authoring tool that you use to create the models and it includes calculators for engine power and airplane speed. Our plan is to provide the ability to export the model and then use a version of Benchmark on the iPhone to calculate the performance of the engine, propeller and airplane. Thus, Benchmark on the iPhone would become an interactive performance section of a flight manual. We have much to do before that becomes a reality, but that is one of our goals.

I originally wrote Benchmark back in a fit of passion around 1990 or so, and it was my first effort at programming. While Benchmark has worked reliably for many years, the user interface was attrocious. I never knew how to go about making it a 'real' program. Matt Emerson approached me about moving Benchmark to Apple's Cocoa programming environment, and for the last few years, we have been working on turning Benchmark into a modern program with an elegant interface. Matt has done the programming to get Benchmark into Cocoa, and I have been working on improvements.

We are going to do the final work on Benchmark in open beta testing. That is, anyone on the internet can download and run the program. It is a fully functional version that only has a few limitations: it expires every month so you will need to get a new version, and it will print "Prerelease" on all printed charts. I am always interested in comments and suggestions, so if you have any, please contact me direct.

Alfred Scott

Let's take a quick tour of Benchmark.



Go back to Benchmark