Posted on 08/03/2006 8:30:46 AM PDT by KeyLargo
what is the point of such a wacked out design?
Aviation Ping
That's an ample amount of alliteration.
Safety. If you lose one engine, a centerline-thrust twin is easier to control than one with the engines mounted on the wings.
Light twins actually have a worse accident record than single-engine planes. With twice the engines, you are twice as likely to have an engine-out event, and when you do, the a standard twin-engine craft becomes a widowmaker. It is likely to stall and/or spin if you make a turn towards the side of the dead engine.
-ccm
An updated version of the Cessna Mixmaster?
Like the old Cessna 337. Push/pull idea. I think the props rotate in opposite directions making for a very stable ride. Also, should one quit, especially on take off, the forces won't want to flip you over.
Bottom line, better control and less drag.
Since it is a pusher-pull configuration (cancelling out engine torque), you very well can't have a conventional tail. This configuration minimizes fuselage cross section, thus drag.
Getting the tail control surfaces away from the engine wash makes control predictable and efficient.
Other details address streamlining and minimum drag.
-ccm
The Eclipse E500 (based in Albuquerque) just received provisional FAA certification. $1.5 million apiece.
"Vern Raburn, chief executive of Eclipse Aviation, says he has over 2,500 orders for the Eclpise E-500, most of which required a non-refundable deposit of $125,000."
Here is the link to the specs and safety information:
http://www.pilotjournal.com/content/2006/marapr/adam_a500.html
"...Another goal of Adam’s push-pull design is to revive the pressurized twin without reintroducing the risks formerly associated with those original, heavy, corporate piston twins. Centerline thrust is regarded as so safe and easy to handle by the FAA that there’s a special twin rating formerly dedicated strictly to the CLT Cessna Skymasters, but now applicable to the Adam A500, as well...."
Flight testing has been going on for 6 or 8 months and certification is expected later this year.
The A500 isn't supposed to be competitive with VLJs. It's a piston twin and is in a totally different market.
The thing to watch with the Eclipse will be any kinds of longevity and manufacturing issues once they go into production. One of the reasons Eclipse is so cheap is that they are using some manufacturing practices to keep costs down. One of those is welding a lot of structures that would be rivetted on a conventionally built aircraft. In the out years I could see some significant NDI requirements if there is ever a failure in one of those welds.
One thing I will say for Eclipse is that they are dealing with liability in a proactive way. When you place an aircraft within the reach of doctors, lawyers, business people you have to fear a rash of mishaps. Can you imagine a Kennedy buying one of these things? The $1.5mil price includes training which they have sourced out to United Airlines in Denver. Depending on your experience level after training you may or may not require some number of hours with a "mentor" pilot. I don't know how Eclipse will enforce that, but that is their intent.
You like vertical stabs? I've got just the car for you.
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