The Homebuilt Difference

Conversation around the airport hangar crowd generally rotates among subjects covering lots of topics, including what this or that airplane is like, which one does this or that best, which is the best performer—things that are long on opinion and frequently more speculation than fact. 

And then someone will say, “What about homebuilts?” and I feel eyeballs turn toward me. I’ve only flown a few dozen homebuilts, out of the hundreds of amateur-constructed experimental designs out there, so I’m hardly an expert. But I am emboldened to render a broad-based opinion, although it’s probably delivered sharply enough to offend some of the hearers in the group. 

Homebuilts are different, I’ll begin. There are no surprises, and very few breakthroughs, when it comes to light aircraft design. Every airplane is a compromise. If you want more of this, you have to give up some of that. Homebuilts simply cut across some of the barriers posed by mass market appeal and FAA certification standards. 

The freedom to build and fly something that doesn’t meet standard certification simply means that an airplane licensed in the experimental-amateur built category (E/ AB) will probably fly differently than the normal/utility category bus you rent from the FBO. Its performance is usually optimized toward a certain criteria that was important to the designer and builder, and you’ll see sacrifices in other details to achieve that end. 

The go-like-hell crowd will subscribe to the ‘great big engine/ little bitty airplane’ concept, some- thing that would have never been available in the certificated market-place because not too many people want to go fast at all cost. Or, in some cases, experimental aircraft builders will shift toward a small, low-cost alternative engine, as a basis for flying reasonably fast and cheap. 

That engine won’t be seen in a certified airplane, and the plane might be too small to fit much of the population” 

But, They Say It Will… 

By now, one of the assemblage will say, “But what about the XYZ Super-Flash? It does 200 knots on 10 gph and is fully aerobatic to boot.” 

I have to issue some disclaimer about the difference between the 200 mph stated in the brochure and the 230 mph implied by his statement, and then note that we have to analyze what is meant by “fully aerobatic.” Like full-IFR, that claim is frequently subject to interpretation. 

At the foundation, I posit, is the whole point of the E/AB category. 

Homebuilding is about freedom to build what you want, using whatever materials you choose, to achieve whatever point you want to make. The category was established to support building airplanes for personal education and enjoyment, rather than commercial practicality. 

Because we are free to build, modify, and change our uncertified aircraft, repeatability is not guaranteed. If the advertisement says “200 mph,” it probably means one specimen may have achieved that benchmark at least once, but an average clone, likely modified with extra space and weight, won’t get there. Claims and representations, in E/ AB aviation, are somewhat speculative targets. It’s not fraud, per se, it’s just that a design’s projected performance, empty weight, build time, or cost is based more on best-case intentions, rather than an average of numbers achieved out in the field. 

In experimental-amateur-built aviation, we are free to exchange our building efforts for a factory’s production line, cutting the cost considerably unless we try to achieve showplane perfection. However, one has to discount the hours and years spent building to obtain these savings. If you have the time and skills, it’s a great trade-off. 

Then there’s freedom of expression. 

A homebuilt airplane is like a blank canvas. We can sketch out pretty much anything we want, putting our own stamp on a design, so long as it doesn’t endanger passengers or the populace below. Even CNC-engi- neered, kit-supplied airplanes are open to modification, within reason, so if we want extra-thick seats, smoke-tinted canopies, drooped wingtips, etc., E/AB allows this freedom. 

Enjoying this flexible approach to aviation results in aircraft that don’t always fly predictably and probably work well for one purpose and not for others. Aircraft design, and modification of a design, is all about compromise. As mentioned, to get more of this, you have to give up some of that. 

So, What’s the Difference? 

If there is a generalization to be made regarding E/AB aircraft, it is that control response will likely be more sensitive than what we experience in standard production planes. 

Stick controls, often unconventional creations like centered or side-mounted sticks, prevail over control yokes. On the first takeoff, you should be ready to use light input pressures, anticipating the controls will be more sensitive and powerful than allowed in certificated airplanes. 

Tailwheel landing gear is more fashionable in homebuilts than in airplanes built for the mass market. Typical characteristics like diminutive size and faster touchdown speed result in such homebuilts having runway handling that’s a notch above the Citabria you might have used to get your tailwheel endorsement. Practice some taxiing and braking before you launch off for the first landing in a homebuilt. 

Don’t expect to find a CFI ready to do a checkout in your newly-acquired homebuilt. The average flight instructor knows little about the type or category involved and can contribute nothing but an evaluation of your ability. If the aircraft has factory support with training available, you would be well advised to spend the money to travel to the plant or bring the factory pilot to your location. 

Among unsupported designs, seek the counsel of other owners and builders. Even if the homebuilt airplane has dual controls, there often is only one set of brakes, and rear-cockpit instrumentation may be lacking, further impeding a checkout. 

Because of the customized nature of E/AB aircraft, it is vital to go over all the paperwork and logs before flying. 

Specific operating limitations are issued when the special airworthiness certificate is awarded and, when the initial 25 or 40 Phase 1 flight test hours or their now-structured equivalent, were flown, documented data should have been gathered to supplement the often-sketchy information in brochures and blueprints. Weight and balance limitations can be critical for a small homebuilt. The specific numbers for the individual airplane should be in the paperwork, providing the basis for working out best and worst cases before flying. Particularly beware of aft-CG loading’s effect on stability. 

It’s critically important to watch for “customized” features when flying someone else’s handiwork. 

Fuel systems seem to be particularly attractive targets for tinkering, as extra tanks and valves are installed, perhaps with transfer pumps, or maybe just gravity feed. The gauging and venting need to be understood, as well as the order of usage from individual tanks. 

Watch out for unlabeled switches and knobs. In vintage homebuilts, features may get removed by simply disconnecting wires or cables, but the old control will be left in place, replaced by a newer one somewhere else. 

All inoperative items should be labeled, and every control needs to be identified by title and function, as in “Cabin Heat-Pull Hot.” Before flying, know what does what, and put temporary reminder labels in place to keep things straight. Know which way the trim knob turns for nose-up, and what the limiting speeds are for the flaps and gear, rather than relying on memories of a briefing. 

Keeping the Chain Intact 

The original builder knew the characteristics and features of their airplane intimately, but this tribal knowledge may have been lost. 

As the distance of years and ownership changes add layers of insulating confusion to a homebuilt, some test flying may be required to reestablish a basis for safe operation. Document the findings in well-logged entries, both for the airplane’s records and your own notes. 

It is important to understand that experimental-amateur built aircraft are individuals. 

Because they did not flow down a frozen-type production line, each one bears the stamp of its maker, as well as the designer. The wonderful freedom to fly a creation of one’s own hands carries with it a responsibility to other persons who may someday fly your personal aircraft. 

It Will Fly About Like It Looks 

Understanding the difference in flight characteristics between certified and E/AB airplanes begins with understanding why there are differences. 

Often, just looking at the airplane tells a lot about what to expect. A small wing, for instance, provides higher cruise speed, but probably means the stalling and landing approach speeds are going to be higher than normal. If the distance between main gear and tailwheel is fairly short, runway handling will be sensitive and steering response quick. A plethora of wings and struts mean a lot of drag, so the glide will be steep and fast. 

Under Part 3 of the old Civil Air Regulations, certificated light airplanes had to have a landing- configuration stall speed no higher than 70 mph, translated to 61 knots in Part 23 of today’s Federal Aviation Regulations (FARs). 

Experimental certification removes this limitation, allowing us to top 300 mph with optimized big-bore engines, but we must accept the reduced crashworthiness of 100 mph landing speeds. Similarly, the FAR standards for crushable seat structure, cockpit visibility, and entry/egress are not mandated. Such nonconformity is the reason E/AB aircraft will have the passenger-warning placard displayed. 

Freedom of expression is at the core of all artwork, and a beautiful homebuilt is certainly a piece of art, worthy of appreciation. Rather than competing with factory-built airplanes, the custom creations of the E/AB category simply represent an alternative path to personal flight. 

Vive la difference!