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#21
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Which sustainer system would you chose for your sailplane?
On Sunday, September 23, 2012 10:16:30 AM UTC-7, John Cochrane wrote:
From an engineering standpoint, I don't really see why the electrics don't also charge the battery. If you climb to 3000', in 20 minutes, surely running the prop in generator mode for 20 minutes or so, doubling your sink rate temporarily, should recharge the batteries? This could make a 3000' capacity enough for self launch and retrieve!. John Cochrane John, I'm not an engineer by any stretch, but your question seems to presume 100% effeciency. Even under ideal circumstances propellers are closer to 80% - - so that would be at least a 20% loss on both discharge and charge. Then there's the heat loss due to friction and resistance of leads and internal motor windings. Couple that with battery heat generation and loss due to internal resistance and chemical processes on both charge and discharge. All this may have one pointing downhill charging batteries for longer than might be comfortable. I get uncomfortable just thinking about it (g). bumper ASH26E . . . like those old Mazda commercials, Wankel engine go MMMMMMMMMMMMM! |
#22
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Which sustainer system would you chose for your sailplane?
On Saturday, September 22, 2012 10:55:27 PM UTC-7, wrote:
Dear gliderpilots! Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system: http://www.front-electric-sustainer.com/voting.php Thank you, Luka Regenerative energy derivation from soaring flight has actually been looked at fairly seriously. This is an interesting read on the subject esoaring.com/regensoaring.pdf Craig |
#23
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Which sustainer system would you chose for your sailplane?
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 Please visit the Wings & Wheels website at www.wingsandwheels.com wrote in message ... Dear gliderpilots! Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system: http://www.front-electric-sustainer.com/voting.php Thank you, Luka |
#24
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Which sustainer system would you chose for your sailplane?
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) |
#25
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Which sustainer system would you chose for your sailplane?
Dne nedelja, 23. september 2012 07:55:27 UTC+2 je oseba napisala:
Dear gliderpilots! Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system: http://www.front-electric-sustainer.com/voting.php Thank you, Luka |
#26
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Which sustainer system would you chose for your sailplane?
I have a Lak 17A with FES. I had the glider already, so a retrofit
sustainer was the only option. I chose the FES for those features which are undoubted advantages compared with an internal combustion engine/pylon. My reasons and the outcome are set out in two articles which are available on Luka’s website. For somebody contemplating a new glider, or for a manufacturer contemplating choices between one route and another, I think there are a number of unknowns. These include the reliability in starting in the air, general reliability, relative safety, hazard warning, longevity, ongoing maintenance costs, battery replacement costs, etc.. My personal opinion, based on very limited numbers of FES and jet, but rather larger numbers of internal combustion engines, is that: FES reliability is unproven, but I have no reason to think that it will be anything other than good. I have a friend with a Lak with a sustainer engine who has landed out several times after it failed to start in the air, with of course a considerably higher decision than the FES needs. The jet is claimed to have a low decision height and quick start up, but I have heard of one user who is onto his third engine which does not sound like good reliability to me, if true. I have no idea whether the jet is close to 100% reliable starting in the air. Lipo batteries based on model aircraft flying and some other applications have a reputation for occasional disastrous fires. The FES system has temperature sensors and warnings which give me some comfort. I have a photograph of fire damage caused to a glider with an internal combustion engine. The pilot did not know until he was landing or had landed that it was destroying the fuselage behind the wing. He was very lucky he was not cruising high at the time. I suspect that the jet has too little service as yet for anyone to know whether it is better or worse. FES Battery replacement costs are likely to be 200-500 units of currency a year on average, maybe less. Electric motors are usually very reliable. I don’t know about the control system. My friend with the internal combustion engine is having cracking problems with his exhaust system. Others have too. I don’t know what other routine or sporadic maintenance costs are involved. I don’t suppose anyone can say what they will be for the jet, although for someone to be on his third motor is not an encouraging sign. I’m certainly very happy with my decision. The range is okay, as an early adopter I don’t have some of the features now available, but it was the right decision for me at the time. For other people, and in the future, there may be good reasons for different choices. In my opinion, nobody can yet know. Chris N |
#27
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Which sustainer system would you chose for your sailplane?
To what altitude can the LAK climb?
LAK17A FES can climb about 1500m LAK17B FES can climb 1250m Regards, Luka |
#28
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Which sustainer system would you chose for your sailplane?
In the US, the FAA required a type rating for any turbine-powered aircraft.
Lately, it seems, they now a Letter of Authorization, to fly a jet powered glider. This letter must be renewed annually with a checkride. Seems a bit extreme for me. Note: My information about the jet glider comes from an acquaintance who just checked out in the Bonus Jet self-launch glider based at Moriarty, NM. "Chris Nicholas" wrote in message ... I have a Lak 17A with FES. I had the glider already, so a retrofit sustainer was the only option. I chose the FES for those features which are undoubted advantages compared with an internal combustion engine/pylon. My reasons and the outcome are set out in two articles which are available on Lukaâ?Ts website. For somebody contemplating a new glider, or for a manufacturer contemplating choices between one route and another, I think there are a number of unknowns. These include the reliability in starting in the air, general reliability, relative safety, hazard warning, longevity, ongoing maintenance costs, battery replacement costs, etc.. My personal opinion, based on very limited numbers of FES and jet, but rather larger numbers of internal combustion engines, is that: FES reliability is unproven, but I have no reason to think that it will be anything other than good. I have a friend with a Lak with a sustainer engine who has landed out several times after it failed to start in the air, with of course a considerably higher decision than the FES needs. The jet is claimed to have a low decision height and quick start up, but I have heard of one user who is onto his third engine which does not sound like good reliability to me, if true. I have no idea whether the jet is close to 100% reliable starting in the air. Lipo batteries based on model aircraft flying and some other applications have a reputation for occasional disastrous fires. The FES system has temperature sensors and warnings which give me some comfort. I have a photograph of fire damage caused to a glider with an internal combustion engine. The pilot did not know until he was landing or had landed that it was destroying the fuselage behind the wing. He was very lucky he was not cruising high at the time. I suspect that the jet has too little service as yet for anyone to know whether it is better or worse. FES Battery replacement costs are likely to be 200-500 units of currency a year on average, maybe less. Electric motors are usually very reliable. I donâ?Tt know about the control system. My friend with the internal combustion engine is having cracking problems with his exhaust system. Others have too. I donâ?Tt know what other routine or sporadic maintenance costs are involved. I donâ?Tt suppose anyone can say what they will be for the jet, although for someone to be on his third motor is not an encouraging sign. Iâ?Tm certainly very happy with my decision. The range is okay, as an early adopter I donâ?Tt have some of the features now available, but it was the right decision for me at the time. For other people, and in the future, there may be good reasons for different choices. In my opinion, nobody can yet know. Chris N |
#29
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Which sustainer system would you chose for your sailplane?
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 |
#30
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Which sustainer system would you chose for your sailplane?
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 As there was a lot of votes today for JET (I think good article on link above helps) I think I need to lighten some more advantages of FES: -Light gliders like Silent, AS13.5, Apis becomes with FES real selflaunchers with comparable or even better climb rates than if equiped with combustion retractable engines. -Even when FES is installed on 18m glider, max climb rate is much better than it is achived with JET or Solo. -As it is slower than JET you do not pass thermals too quickly, but you can do some turns to center (under power or even without, at normal thermaling speeds) and preserve energy. Actually is it suprising how much energy is even in weak thermals. -You can use it in mountains, on the ridge to help you climb above the peaks. Even that you have motor you still feel it as soaring, so not bad feling... -FES is possible to use even in horizontal flight trough (not too heavy) rain (ventlation is prefared to be closed) without fear to damage proppeller blades up to about 3500 RPM. -Only at FES start is instant, so it can save you out of unladable valleys. Regards, Luka |
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