Dne torek, 25. september 2012 18:00:15 UTC+2 je oseba Eric Greenwell napisala:
On 9/25/2012 7:21 AM, Tim Mara wrote:

For performance, low weight, LOW drag, simplicity and safety. JET!

More manufacturers are developing or exploring Jet sustainers. Quite simply

the lack of moving parts, the very low weight to power output and when

properly configured to have the computer take the pilot out of decision

making of the actual operation of the engine the reliability of operation

make the Jet the best possible solution. The HpH 304 Jet doesn't require

massive, heavy and possibly hazardous batteries, doesn't require start-up

and operation or typical reciprocating engines, no priming, no chocking,

decompressing or diving to windmill and engine to start, no high parasitic

drag (the jet engine expended has actually less drag than the landing gear

down), no wind milling propellers, and short time from switch on the switch

off and stored, literally seconds to start so even at low altitudes can be

operational in seconds and without the high drag of a propeller is a non

issue when it might be necessary to glide the extra distance to make a safe

landing with an extended powerplant.

The Jet does have to be engineered right from the start and have systems

that are completely monitored and controlled by a computer system to take

the operator error possibility away and this is what has likely delayed the

release of the Jet sustainers from most manufacturers. Having flown just

about al types from simple 2 cycle ultra-lites to small corporate Jet

aircraft I can see potential issues with operators not fully trained in Jet

engine operation without the development of a computer based system to

control the operation of the jet engine. With the HpH system the controller

monitors all aspects of the engine from start-up to engine cool down and

stowage, it is simply refined ...

regards



Tim makes some excellent points for the jet sustainer, but every one of

them also applies to the FES. Sure, it's got those "possibly hazardous

batteries", but it does not have those "possibly hazardous 8 gallons of

fuel".



This illustrates the problem with the current voting choices, offered

without any description of each systems attributes. Even a dealer does

not tell us the important differences between two of the three choices,

so how can the average "voter" make an informed choice?



--

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

email me)


I will write here just a few attributes of the FES which I think are the most important:

-reliable start, full power available in 1s, switching off also very quick
-no smell in cockpit, no oil on fuselage
-small noise outside and inside of cockpit
-low vibrations
-good max climb rate about 2,5m/s at 22kW for LAK17A (depend on weigh of glider)
-very efficient system (only 4kW of power is neccesery for horizontal flight) which gives about 100km of range
-big advantage is that 12V power is available from main baterie pack, (DC/DC converter) so you have finally enough power for Radio, Transponder, PDA, Vario etc, acctually for the whole flying season
-all 12V Pb batteries can be removed (this mean usually minus 5kg)
-only about 50kg of additional weigh - 5kg of Pb= 45kg
-no change of drag or CG position during engine run
-according Idaflieg test results, drag of propeller blades is really minimal (official results published in winter)
-very chaep charging of batteries, outside of glider
-virtually maintenance-free
-price in range of Solo sustainers

Articles about FES:
http://www.front-electric-sustainer.com/articles.php

Very good article about recent JETs:
http://www.psr-jet-system.com/___010...gelfliegen.pdf

There is not much about Solo sustainers but here is one:
http://www.trb.8m.com/

So now is up to you to take some time to read and decide which one you would choose!

Regards,

Luka