I think Bob K's post just above yours says it all. We already have wonderful XC trainers with engines - they're called Duo Discuses (Discii). They cost a lot of money, and very few blue collar glider training operations are going to buy one, at least here in the US. I'm sorry, but Greg may be disconnected from the realities of a typical club or low budget FBO. Managing a sophisticated system like you describe? Hah! I watch what the ASK-21s, Blanik L-23s, and 2-33s go through at our operation and those nearby. We're lucky if we can keep the 12V SLA battery charged with working connectors in order to run the radio and electric vario :-)

Seriously: Simple. Robust. User Friendly. Repairable. ASK-21 performance.

That's the high level requirement IMO.



On Friday, April 5, 2013 12:03:48 PM UTC-4, Eric Greenwell wrote:
On 4/5/2013 4:24 AM, Evan Ludeman wrote:

No motors! That adds cost, complexity and training issues all out of

proportion to any supposed benefit as a trainer. We need *trainers*

and a safe, reliable, economical way to launch them. The PW-6 is the

closest thing on the market.



Greg's belief is we need *soaring* and *XC* trainers, not just

"trainers". He absolutely wants to avoid the cost, complexity and

training issues of the current gasoline engine systems, and that is why

he want to use a TFP system ("Tractor folding propeller" - same concept

as the FES, but that name belongs to another company). The cost,

complexity, and training issues are far smaller with an electric folding

propeller sustainer than gasoline sustainers, or self-launcher systems

like the ASK-21 Mi. Any instructor should be able to make good use of a

TFP after a few flights, and students could be ready to use it as well

by the time they are solo.



The TFP addresses the "safe, reliable, economical way" to launch the

glider, using a car launch to 500 feet.



I think training effectiveness would be increased if the instructor

could extend the flight with another climb instead of landing, and with

just a flick of a switch.



Think how exciting it would be for a student who isn't solo, but has

progressed to flying the glider for most of the flight, if part (or

all!) of the flight included real XC flying, beyond gliding range of the

airport? I think that would eliminate the huge "rubber band" effect most

solo students experience, and that continues to haunt them even when

they get their license.



That excitement would keep them coming back better than the typical

training program does now, don't you think?



--

Eric Greenwell - Washington State, USA (change ".netto" to ".us" to

email me)