Homebuilder's Workshop - November 2013

Perspectives

By Ed Wischmeyer

So now that I’ve rejoined the ranks of “real” pilots with a homebuilt taildragger, namely an RV-8, here are my unimpeachable thoughts on life, the universe, and all that.

Tailwheel vs. Nosewheel

Actually, there are several kinds of tailwheel skills. There’s the faster landing tailwheel airplanes like the RV-8, and the slow landing kind like the AirCam I used to own. When I got the RV-8, it was a real surprise how much my skills had degraded. A tailwheel airplane will keep your skills at a level higher than required for a nosewheel airplane. But the flip side is that the nosewheel airplane is easier to land when you’re tired or in ugly wind conditions (safety), at night if you’re trying to make a wheel landing, and a nosewheel gives you over the nose visibility when taxiing (safety).  There are few circumstances that legitimately demand a tailwheel, so the nosewheel wins hands down. But I’m not in any hurry to sell my new RV-8.

Low vs High Wing

High wing airplanes have a better ride in turbulence, provide shade in flight on those hot summer days – especially compared to a bubble canopy, are great for sightseeing, and let you get in and out more gracefully in the rain. Low wing airplanes seem less susceptible to gusty crosswinds, and are easier to fuel – if not to drain the sumps. So high wings tend to win for many applications.

Fixed Pitch vs Constant Speed Props

Depends on the airplane. If your plane has a limited speed range, fixed pitch props are fine, as on the AirCam. If your plane has a wide speed range, like the RV-8, your choice of prop pitch will determine whether you gain cruise speed at the expense of takeoff and climb, or vice versa. And don’t overlook drag from a constant speed propeller in flat pitch, and that can be real handy for slowing down a clean airframe. The other place where a constant speed prop wins is at higher density altitudes, where a constant speed prop lets the engine turn at full RPM on takeoff to give you all the performance that’s in the airplane.

Control Wheels vs Sticks vs Sidesticks

Sticks win for aerobatics, wheels win for IFR, and sidesticks win for getting the control out of the way. Sidesticks lose on planes with high aileron forces because you can’t use the big muscles in the arm. Sidesticks also lose when you need to switch hands on the stick, because reaching across your body is awkward. Planes with control wheels are generally easier to get in and out of.

Cost of Ownership

Within reason, the costs are not much different between owning a fast airplane and a cheap, slow, “economical” airplane. Why? Hangar costs are exactly the same, insurance costs for liability are about the same (hull insurance will go as a percentage of the insured value, and if both planes are fixed gear, the rate will be comparable), and annual inspections (if hired out) won’t vary that much, either. The differences between a “cheap” airplane and an “expensive” airplane will be in cost of gas and cost of monthly payments.

Accessibility

One of the major “costs” of ownership is how accessible the airplane is. Specifically, how long does it take from going out your door to starting the aircraft’s engine and, similarly, how long does it take from shutting off the aircraft’s engine to walking in your front door. Distance to the airport is a major factor, but other factors are how much of a hassle it is to wrestle the plane in and out, including moving hangar doors, moving a car several times, etc. Folding wings can help with the distance to the airport, but the time to fold and unfold the wings can hurt the time to airborne. Getting gas at a pump and restarting the airplane to taxi to the hangar or parking spot is another factor. But here’s an interesting thought: wings will get folded mostly at the home airport.

Autogas vs Avgas

The real win in aviation will be when you can take pump gas of whatever ethanol concentration and use it in your (probably experimental) airplane. And the claims about ethanol being for cleaner air – I don’t get it. Modern automotive engines have oxygen sensors and sensors of all sorts to run super clean and super efficient. For example, my seven-year-old, two-liter, turbocharged Audi gets better gas mileage (and produces six times the power) of the 1.2 liter VW that I drove in high school. But fully electronic airplane engines, with variable valve timing and the like, remain well in the future.

Auto Engine in Airplanes

No problem with the engine! The problems are all in the installation, with vibration and cooling leading the charge. Reliable (usually meaning redundant) electrical power and reliable electronic engine control are other significant issues.

Buying an Airplane

When you buy an airplane, especially a homebuilt, you are – to a certain extent – buying the integrity of the seller and of the airplane designer. Those factors should be as important to you as the pre-buy inspection of the airplane.