what_next wrote:
Maybe, but still I don’t see how the advantages of a pusher could outweigh it’s shortcomings.
It usually doesn’t. But I guess many of those designers either don’t care (i.e. no economical constraints, like someone designing stuff because they want to and because they think it looks cool), or they lack the education, the knowledge and/or the will to proper assess the options. Or both.
Or they’re Burt Rutan, designing a plane about which builders like Klaus Savier can say “top speed is >260mph and the cruise speed is > 250mph at 17,500 ft using less than 7 gph” Surely not every plane has to be well rounded into total boredom… Some can be good at some things, not so good at others.
There are some advantages with a pusher, especially for canard designs, which would be very awkward to design with a tractor. What are the advantages with a canard, is a good question of course, but there definitely are some. With experimentals you don’t have to only look at what sells by the millions (or a few hundreds regarding light GA 
)
A light aircraft for the masses is a compromise of producing the best aircraft possible for the least amount of dollars, and the ability to sell it for the largest amount of dollars possible (or whatever currency is hot). This makes dollars the most important engineering factor in design of light aircraft. For an experimental, dollars are not usually the most important factor when designing. It certainly can be, but it’s not all that important for a successful design. For an experimental it is often enough to utilize some odd aerodynamic theory or some odd construction method, which is why experimental aircraft are in general much more interesting and varied than the mass produced counterparts.
Well Rutan had build a Canard in Push-Pull configuration with the Defender. Or even a sole tractor with the Quickie (a try to eliminate a few of the more obvious problems of canard aircraft). If I remember the story correctly, his initial design were not for economic purposes, but for personal use and for the challenge to pull off such a design. Only after he had some experience (and publicity) with his canard he opted to sell the plans / kits.
However, the Canard design itself is less than ideal. There isn’t much advantage other than looks, especially in a pusher configuration. Even aerodynamically the high wing loading of the canard itself and the impact on the main wing aerodynamics are huge disadvantages of the canard design.
LeSving thank you for photos and report – it is the EAA show, so good you looked under a lot of experimental rocks.
On the pusher question, the mixmaster 337 has better SE climb performance with the pusher prop than the tractor prop. I recall there was an STC to replace the rear engine with a turboprop, and they then streamlined the front and did away with the front engine.
Rutan built all kinds of crazy things. That scarecrow looking contraption (double lifting surface) up there is one of his designs. He is probably the number one example of a designer with no or very limited restrictions of any kind. Nevertheless, his canards with pushers keep on living even today. There is no doubt they are very efficient aircraft, and they look good.
A certain “class” of modern high performance microlights have gone into the equal looking mode. They all look the same, they perform the same, they are all carbon and they cost the same (a lot). This has happened because the market is the main driver, and this is how a microlight will look and perform when everything is optimized with regard to making most amount of dollars (or Euro in this case).
RobertL18C wrote:
so good you looked under a lot of experimental rocks.
I have lots of more pictures. These were just a more or less random selection
Of the more “mainstream” I think that Jabiru was amazing. It’s an LSA, but can also be built as an experimental I believe, With a 120 HP Jabiru it cruises faster, longer and take more “cargo” than a C-172. A really nice airplane, that was constantly crowded with people. Especially for the LSA market, it must be the only one that can carry two people with lots of luggage over great distances. The internal “luggage bay” was huge.
Silvaire wrote:
Or they’re Burt Rutan, designing a plane about which builders like Klaus Savier can say “top speed is >260mph and the cruise speed is > 250mph at 17,500 ft using less than 7 gph”
Since when do we believe in figures quoted by designers, builders and owners? 
And what are “miles per hour” anyway… And then, who knows what these figures would look like if Rutan would have designed it as a tractor instead of a pusher…
LeSving wrote:
There are some advantages with a pusher, especially for canard designs, which would be very awkward to design with a tractor.
With canards and flying wings, the pusher configuration is necessary because of mass and balance considerations (or alternatively a front propeller need to be driven by a long shaft). Since the fuselage is in front of the wing, something heavy must be behind to balance it.
And yes, tractor canards (of which there have been built very few) look terribly awkward:
what_next wrote:
And yes, tractor canards (of which there have been built very few) look terribly awkward
LeSving wrote:
With a 120 HP Jabiru it cruises faster, longer and take more “cargo” than a C-172.
Are you referring to the Jabiru J230-D? It has a useful load of 230 kg. What C172 has less? The C172R has about the same fuel consumption and range, but it is certainly slower.
No doubt that many UL and LSA aircraft have impressive performance — there is no need to exaggerate.
Airborne_Again wrote:
No doubt that many UL and LSA aircraft have impressive performance — there is no need to exaggerate.
Considering the Jabiru J230-D cost US$125k brand new, with g3x and autopilot this is no exaggerating. This is a two seat aircraft (two persons and 3-4 dogs ) It’s MTOW is 1320 lbs due to LSA regs, but it’s designed to 1540 lbs MTOW (all composite design, has been tested to 9g at MTOW). Empty weight is 850 lbs, and the max baggage weight is 260 lbs.
Cruise speed: 120 kts
Stall speed 38 kts
Fuel capacity: 35 gal
Fuel consumption: 5.5 gph (endurance, more than 6 hours)
It has 313 kg max load. With full tanks that leaves 218 kg for passengers and luggage. It’s similar in some ways to a Glastar/Sportsman, only the Glastar has even better specs due to larger engine, and cost 50% more (as a kit). You could of course rip out the back seats of a C-172…
