Q. Why do we need a weight and balance calculator for helicopters?
A. There are several valid reasons, but the most important ones are that the manufacturer specifies a figure known as the Maximum Gross Weight. This is the weight you are not allowed to exceed due to the fact that you could compromise the structural integrity of the airframe, and you will not be able to predict the performance of the helicopter (the helicopter is provided with charts that enable you to determine how it will perform and if you exceed the Max Gross Weight figure, then the charts are invalid and you will no longer be predicting, but 'guessing' helicopter performance. You don't want to do that. Another reasonably sound argument is that it is illegal to exceed Max Gross Weight. Do we need more reasons?
Q. Okay. But why did you go to the trouble of a calculator?
A. In 2006 I followed a dream and started to learn to fly helicopters. I learned that helicopters (all aircraft) can only carry a certain amount of weight, and the more they carry, the poorer the performance. So it became apparent that it was important to determine not only how much weight was onboard prior to liftoff, but also WHERE that weight was distributed.
Q. Why didn't you buy one of those electronic calculators?
A. The answer is that I was a struggling student with not much spare cash and couldn't justify $80 on the CX-2 (that was 20 minutes of a training flight!)
Q. What inspired it?
A. The calculations involved were (to me), somewhat confusing, because the numbers were made of of a lot of other numbers with lots of zeros and what not, and I found I would make mistakes regularly. So I thought about that and how annoyed I would get making mistakes, and came up with the idea of getting a program like MS Excel do all the work for me. (Despite the fact that I've spent an insanely ridiculous amount of time working on the calculators, I really am quite lazy and wanted it all automated!). And the more I worked on them, the more I learned about neat little things that Excel could do to make it even easier for myself, like little messages that would pop up and tell me I couldn't take a particular fuel load onboard unless I offloaded one of the fatties on board...and the fact that it would not let me overload the helicopter.
Q. What does the calculator do?
A. I'm glad you asked. The calculator determines how much weight you have onboard and whether you are legal (or you can use it to figure out much fuel you can load in it and stay legal). It also plots your gross weight with loaded fuel, gross weight after you've been flying, and a neat thing, it plots your center of gravity within the CG envelope.
Q. Whoa. What's Center of Gravity and what's a CG envelope.
A. Your helicopter is provided with a POH in which you will find your CG envelope (not all manufacturer's provide a CG envelope, but training helicopters do). This envelope is a window so to speak, where your weight limits are allowed to be. The window indicates forward, aft, and left and right limitations. The calulator plots on the envelope which way you can expect the helicopter to move when you lift off the ground. This gives you a good indication of which way to hold the cyclic prior to lift off. It's quite neat, really.
Q. How can you extort nearly $5 for an excel calculator?
A. Well, it's not really just me. You see, there are a bunch of other co-extortionists, too. First of all there's the coffee. Good coffee (not that St*rb*cks dishwater, either) does come at a price. Around $3.50 for anything with an espresso shot in it. Then there's the guys that help me out occasionally with ideas for the calculators. Oh and then there's the eBay and Paypal fees, which average $1 per transaction. Ouch, that's 20% taken out right there. Go back through my feedback; many people have mentioned they would pay a lot more for the calculators. $5 is really not too bad in today's marketplace.
Q. How does it work?
A. Magic. (Is anyone really reading this far?). Without giving away the secrets, it's really very easy. The calculators come with several fields; you can only enter information into a field that is highlighted blue. As you enter the information, the CG envelope and weights are updated. It takes less than 30 seconds to enter the information in the smaller calculators.
Q. What models do you make the calculators for?
A. It all started with the Robinson R22. Then we went for the R44. We now have a decent lineup, including Safari (Baby Belle) models, Bell Jetranger and Longranger, and a couple of others that elude my memory right now.
Q. Will you make one for a helicopter not in your list, and for how much?
A. All calculators are $4.95. If we don't have it, and you can provide some information from the POH (we will advise what we need), then we will make it for you for no extra charge. And hey, maybe we'll get to sell it again in the future!