RotorTalk Newsletter

RotorTalk HeliflightUK Newsletter

RotorTalk - HeliflightUK Newsletter

I had some more work published recently in RotorTalk the official newsletter of HeliflightUK Ltd.. They used several of my photos from Western-super-Mare Helidays back in July. I also wrote an article for them comparing model helicopters with flying full-size machines.

You can download the newsletter below, it’s just over 2MB in size so might take a little while.

Student’s Progress Report for Flight Instructors

Progress Report

Student's Progress Report

This progress report spreadsheet automates all the calculations and ensures accurate and tidy recording of your student’s progress. Simply enter the date to activate each sector, and then enter the flight time in the appropriate column. All headings are replicated on each printed page, so you can just keep logging flights without having to worry about which page you are on or how many you have used. Just go to print preview and select which page you would like to print, then file it away in your student’s permanent folder. No more tippex!

Please feel free to leave any comments or suggestions on how the Progress Report spreadsheet could be improved.

  Progress Report Log (597.5 KiB, 736 hits)

Legal Stuff

 

All files and tools on this page are provided “as is” with no express or implied warranty for accuracy or accessibility. Use at your own risk. All calculations should be checked before being relied upon for flight planning purposes.

Digital Flight Planner

Ready to throw the whiz-wheel out the window? Have a look at this flight planning spreadsheet that includes the solution to the Triangle of Velocities. With a convenient knee-board sized output and large clear display of all the most important information, you may never need your whiz-wheel again!

Simply enter your desired track, true air speed, wind forecast, and distance on the flight log just as you would with the paper equivalent. The spreadsheet then calculates the heading you require, your ground speed, and your estimated time enroute.

Mathematical Solution to the Triangle of Velocities

The motion of an aircraft relative to the surface of the Earth is made up of two velocities. These are the aircraft moving relative to the air mass, and the air mass moving relative to the surface of the Earth. Adding these two vectors together gives us the aircrafts motion over the ground. Together, they form the “triangle of velocities”.

A wind that is blowing from the left will carry an aircraft onto a track that is to the right of the heading. In order to achieve a particular track from A to B the aircraft must be turned into-wind by an amount that corrects for the drift.

Each of the three vectors in the triangle of velocities has two properties – magnitude and direction. This means that there are a total of six components. These are the True Air Speed (TAS) and heading (HDG) of the aircraft, the speed and direction of the wind (W/V), and the Ground Speed (GS) and track (TR) of the path over the ground. This is shown in Figure 1 – The Triangle of Velocities.

Figure 1 - Triangle of Velocities

Figure 1 - Triangle of Velocities

Typical navigation problems involve finding two of these properties when given the other four. For example, most of the time we know what track and air speed we would like and we also have the forecast wind velocity. What heading do we need to steer to follow that track, and what ground speed will we achieve?

The usual method of solving this problem is with a “Flight Computer” such as the E-6B also known as a “whiz wheel”. The wind side of the flight computer consists of a circular rotating compass rose which is marked with an index at the top, and has a transparent screen in the middle to allow viewing of the slide plate underneath. The slide plate is marked with concentric speed arcs and radial drift lines. The computer allows you to physically visualise the triangle of velocities, and read off the answer you require. But what calculations is the flight computer performing? How do you solve the problem mathematically?


Calculating the Required Heading

In order to find the heading required, we need to make use of the sine rule. The sine rule states that for any triangle the ratio between a given side length and the sine of the corresponding angle is equal for each side of the triangle – Figure 2.

Figure 2 - The Sine Rule

Figure 2 - The Sine Rule

We simply substitute in the parameters from Figure 1, and rearrange to solve for our heading (HDG). Thus,

Heading Equation


Calculating the Ground Speed

The ground speed is simply the magnitude of our track vector. The easiest way to determine this value is to divide the triangle of velocities up into two right-angled triangles – Figure 3.

Figure 3 - Ground Speed

Figure 3 - Ground Speed

The length of the track vector is then just the sum of the x-component of our velocity through the air mass and the x-component of the wind velocity.

Ground Speed Equation


Flight Planning

These equations are quite cumbersome, and if working out the solutions by hand then by far the quickest solution is to use the whiz wheel. However, now that we understand the mathematical solutions it is possible to enter them into a spreadsheet and speed up the flight planning process considerably.

Robinson Helicopter Weight and Balance

Struggling with the pre-flight weight and balance calculations on your Robinson R22 or R44 helicopter? Then try out these MS Excel spreadsheets. Unlike many of the other weight and balance spreadsheets available on the internet, this CG calculator has a clean and readable layout. It is also very easily customised to match the details of your own aircraft.

Robinson R22 R44 Weight and Balance Calculator

Robinson R22 R44 Weight and Balance Calculator

Simply enter your weight, and the weight of your passengers plus their baggage, and the calculator will tell you how much fuel you can load to reach MTOW, and also show you the CG position on the charts taken from the POH. Simple drop-down lists allow you to choose your doors and dual-control configuration, and see how the change in weight affects your CG position. If things start to light up red – you know you’re overloaded! All you need to do is add the details of your aircraft to the data tables, and you’re good to go.

Please feel free to leave any comments or suggestions on how the CG calculator could be improved.

  R22 Weight and Balance spreadsheet (14.1 KiB, 3,823 hits)

  R44 Weight and Balance spreadsheet (17.8 KiB, 4,405 hits)

Legal Stuff

All files and tools on this page are provided “as is” with no express or implied warranty for accuracy or accessibility. Use at your own risk. All calculations should be checked against the relevant pilot’s operating hand book before being relied upon for flight planning purposes.