Good point Silvaire – from an accountant’s perspective the Seneca 1, possibly on the least likely to top the poll list, has provided some very good Return on Investment having being made from the Six and Arrow’s parts bin and still a revenue earner for operators forty years on. Now a list of how to better the Seneca 1 might be quite a long one.
Types that have survived the test of time, which always means a compromise on design and handling, tend to be the unsung heroes of these polls.
As I write, my wife says she feels the same about variety 
Speaking of variety, and maybe sort of on topic, I was traveling on business this week, saw a Lycoming powered DA42 on the ramp, and had a quick look. Biggish engines on a little plane! That’s always good.
I think GA is a good demonstration of the principle that there is no free lunch in physics.
Every attempt to depart from the mundane and boring produces something that addresses the one objective but is a severe compromise in numerous other areas
saw a Lycoming powered DA42
I took the liberty of adding yet another vote for the DA42. (Aart’s vote covered the diesel verion only)
I think there is one free lunch in physics (in relation to aircraft) and that is the introduction of anything that saves structural weight as a result of improved materials or good structural design.
If I really had to vote for a best aircraft I think I’d vote for the Vans RV7A, it seems to violate the laws of physics in terms of all around performance and functionality. I think in actuality what it does is recognize that weight saving is disproportionately important, in this case without the need for advanced materials.
Interesting… most 140kt+ GA flies so far up the curve that most drag is parasitic, so weight is not important. My TB20 does 138kt IAS at specific low level economy cruise settings, no matter who is inside. Maybe a 2kt change…
IMHO the RV (and others like the Lancairs) get the speed primarily via displacing little air, i.e. a small tight cockpit. That is by far the biggest factor at these speeds. Whether that is a compromise depends on how well you know the RHS 
A further drag improvement (which the RV has beneficially avoided exploring too far) comes from having minimal wings and control surfaces, but that brings severe compromises (a high Vs and other dodgy low speed handling, low yaw stability, low xwind limit due to low elevator authority) which all prevent certification. Whether they matter depends on your mission profile (types of runways, mainly, and need to cope with ice) and attitude to risk.
About the only area where you can still play is the improvement of low speed handling via the use of flaps. Transport jets take that very far, but they avoid the 60kt Vs limit by having 2+ engines. Also I can’t see how to have even bigger flaps on a GA SEP… Socata did manage to achieve a huge amount of payload by lifting Vs to 65kt – amazing, and shows how SEP certification is a controlling parameter.
I voted…..yep, you guessed!
Yes, the Lycoming version of the DA42 is an interesting machine, but apparently only built for the US market, that had (has?) cold feet when it comes to Diesels. A reasonable rocket too, but starting to lose that advantage over the Diesel versions when higher than 8000 ft I believe. Also, a lot of engine levers in a narrow cockpit..
Emir, where are you? Get that vote in so that at least at EuroGA we are the clear winner. We can divide and conquer here.
Interesting… most 140kt+ GA flies so far up the curve that most drag is parasitic, so weight is not important
That’s a new one. Weight is always important. Induced drag is proportional to the square of the lift (weight) if I’m not mistaken. Things like climb rate, needed runway length, stall speed, aerobatic ability and general handling is highly affected by weight. The RV-7 is an all round aircraft. Takes off in 500 feet gross weight, climbs at 2500 ft/min, cruises at 180 and is aerobatic.
To see what low weight can do, a flight in a friend’s Wittman Tailwind is instructive: it weighs 830 lbs and has 160 HP. The thing can operate out of Cub style runways, carries two people side-by-side behind big doors, plus plenty of baggage, plus plenty of fuel in huge wing tanks, climbs at 2500 fpm, and is as fast as tandem seating RV4 on the same power – I’ve been in it while flying at 207 mph IAS. That said, nobody would nominate the Tailwind as the best GA aircraft – its extremely loud and quite fragile to get to that low weight. The RV7 (in either tail wheel or nose wheel versions) goes in the same direction in terms of design for low weight but with much more practicality, meaning a little more power & fuel burn.
The RV7 cabin is really quite roomy, I think its 42 inches wide but there is no center console between the seats and a lot of head room. Despite the RV14 being developed subsequently for really giant, fat people I can’t see a need for more room than an RV7 already has. To each his own anyway, I don’t own any of the planes being proposed as ‘best’.
