When someone contacts Alan wanting to test-ride a GNAT, he is likely to suggest they first try riding lots of other recumbent trikes. If they later ride a GNAT, they will certainly appreciate the difference, and probably want one!
The heart of a GNAT is the chassis. Aesthetically, depending on which way you look at it, this moulding is either pleasingly bottom-shaped, or depressingly reminiscent of a coffin.
The chassis replaces around two dozen one-inch-diameter tubes in the steel trike from which the current GNAT evolved. Steel tubes would make for a very expensive trike - not because they are expensive themselves, but because joining them takes a long time, as anyone who has built a cycle frame knows. Have A Peek Inside Nick's Workshop if you want to get an idea of the sort of work involved. The GNAT's steelwork is brazed, producing better-quality joints than welding, which is nevertheless used on some other recumbent trikes.
You may have come across some remark by some cycling guru - maybe someone who must know what he is talking about because he has been doing exactly the same thing for donkeys' years - to the effect that glassfibre is unsuitable for cycle frames. If so, you might be thinking that, at the very least, the chassis is a concession towards economy.
This sounds like a worn-out advertising slogan, but .. the chassis is no compromise: It is lighter and stiffer than if it had been made in steel; it won't break even if you crash into a wall (but if you did you should be able to repair it yourself); it won't rust and never needs painting. If you didn't have much money, but wanted something like a GNAT, you should at least buy a chassis, even if you make the other bits yourself (although I would suggest you also get the front wishbones and axle carriers, since their geometry is important). You could not make something better than the GNAT's chassis at any price, and certainly not in steel.
The chassis is designed to give overall stiffness, and local strength - the latter for example around the screw-holes where the brackets are attached. Strength doesn't need a lot of substance:- there is strength enough in the suspension webbings, thin strips of woven nylon that you can have in your pocket without knowing they are there. Overall, the chassis needs stiffness, and the GNAT has so much of it that without suspension it would be uncomfortable. Yet - and this might come as news to some people - suspension is not just there for your comfort. It also keeps the wheels on the road, and reduces mechanical stresses.
Another design aim of the chassis is to distribute wheel loads over large rectangular areas. This keeps stress and therefore flexing of the chassis to a minimum. Given this design, the glass-fibre chassis is plenty strong enough; it would not weigh significantly less in carbon.
Elasticity permeates the realm of mechanics. Things flex in proportion to applied stresses. This rule holds even for very rigid-looking structures, and the result is usually unwelcome. In the case of some trikes going round corners, sideways forces change the geometry of the wheels appreciably, altering the steering characteristics, changing the line through the corner, again changing the forces, ... and so on. Quite apart from the comfort factor, riding a trike of this sort for any distance can be a tedious business, if you have experienced something better, although like most things you can get used to it.
However, when you get used to a GNAT, I don't think you would want to ride anything else. At any rate, the last time I rode a nonsuspended recumbent trike, the ride was intolerable after a short distance. Try this test, on a GNAT if you can, and any other recumbent trike: Hold the back of the seat with one hand, and with the other, see how far you can flex the top of the back wheel sideways, using a reasonable amount of force (right). Make sure you are holding the seat firmly, since you want to feel the flex between rear axle and seat, not front-suspension movement. Movement here translates directly into sloppy handling on the road; you may be surprised how much there is in some recument trikes, even those that have tubes running between the rear axle and seat top, and are thus literally a pain in the neck to ride. The GNAT, on the other hand, isolates you very nicely from rear-wheel vibration, as you can probably see from the picture. While you have your hand on the GNAT's seat back, press down and feel the suspension movement - more than you might expect from a piece of nylon! Whether you go slow or fast, the GNAT gives you a great ride.