If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
How high can you fly?
On Sep 19, 12:12*am, wrote:
Mark wrote: On Sep 18, 6:55*pm, wrote: Mark wrote: Clarification: With regard to the cooling of a sealed brushless motor, your concerns and comments about air density are basically irrelevant. They cool differently than open typical electric motors that rely on air circulation. Yeah, how is that, magic? There are only two ways to cool any motor, and it doesn't matter whether it is an ICE or electric. You either put a bunch of pipes in the motor, run a fluid through them, and dump the heat with a radiator that has air flowing through it or you put cooling fins on the motor and that have air flowing over them. And air at altitude may be cold, but it is also thin which means you have to move a lot more air at altitude than sea level to get the same cooling. -- Jim Pennino Correct. The higher you go, the harder it is to displace the heat. I believe the topic of this post is..."How high *can* you go?" So you are finally giving up on your assertion that a sealed brushless motor is magic and won't need cooling? This doesn't mean you cannot have electric airplanes, or that at 20,000 ft. they aren't superior to internal combustion. Electric airplanes are not and will not be superior to ICE airplanes at any altitude any time in the foreseeable future. There are already GA aircraft that regularly fly at flight levels, though most of them that go much over 20,000 feet don't use pistons in the engine. There is no market for small, as in C172 size, airplanes that can get to the flight levels or someone would already be making them powered by small turbines. snip babble -- Jim Pennino Remove .spam.sux to reply.- Hide quoted text - - Show quoted text - Thanks Jim. --- Mark |
#22
|
|||
|
|||
How high can you fly?
On Sep 19, 12:12*am, wrote:
So you are finally giving up on your assertion that a sealed brushless motor is magic and won't need cooling? Who ever said that a sealed brushless motor is magic and won't need cooling? I certainly didn't. This is just another example of your revisionistic debating style. This doesn't mean you cannot have electric airplanes, or that at 20,000 ft. they aren't superior to internal combustion. Electric airplanes are not and will not be superior to ICE airplanes at any altitude any time in the foreseeable future. Most people are unable to see beyond today. I don't envision heavy low-density batteries. No ICE dragster can beat an electric one. That's real now. Yes, it's short run. Yes gravity isn't a factor. But people are flying electric planes today. That's real. Billions are being spent on a better power technology...and I believe they're going to make it and when they do...I will retrofit a plane such as one that currently is an LSA. There are already GA aircraft that regularly fly at flight levels, though most of them that go much over 20,000 feet don't use pistons in the engine. And if they didn't need oxygen for combustion... There is no market for small, as in C172 size, airplanes that can get to the flight levels or someone would already be making them powered by small turbines. That's because it's too specialized. An electric plane can fly at any elevation it want's to under the stratosphere until air density prevents lift, or cooling is impossible. Therefore a cheap retrofitted small plane would simply fly over inclement weather, changing the paradigm of general aviation. And, the fun level would be off the chart. snip your snip --- Mark -- Jim Pennino |
#23
|
|||
|
|||
How high can you fly?
Mark wrote:
On Sep 19, 12:12Â*am, wrote: So you are finally giving up on your assertion that a sealed brushless motor is magic and won't need cooling? Who ever said that a sealed brushless motor is magic and won't need cooling? I certainly didn't. This is just another example of your revisionistic debating style. This doesn't mean you cannot have electric airplanes, or that at 20,000 ft. they aren't superior to internal combustion. Electric airplanes are not and will not be superior to ICE airplanes at any altitude any time in the foreseeable future. Most people are unable to see beyond today. I don't envision heavy low-density batteries. No ICE dragster can beat an electric one. That's real now. Yes, it's short run. Yes gravity isn't a factor. But people are flying electric planes today. That's real. Billions are being spent on a better power technology...and I believe they're going to make it and when they do...I will retrofit a plane such as one that currently is an LSA. Yeah, sure, and it is going to happen any day now along with controlled fusion, a cure for the common cold, and artificial intelligence. There are already GA aircraft that regularly fly at flight levels, though most of them that go much over 20,000 feet don't use pistons in the engine. And if they didn't need oxygen for combustion... No one would care. There is no market for small, as in C172 size, airplanes that can get to the flight levels or someone would already be making them powered by small turbines. That's because it's too specialized. An electric plane can fly at any elevation it want's to under the stratosphere until air density prevents lift, or cooling is impossible. Nope, doable today with either a turbocharger on a piston engine or a turbine. A turbine would get you higher, but there is no market for even a turbocharged C172 size airplane. And it doesn't require magic batteries that don't exist. Therefore a cheap retrofitted small plane would simply fly over inclement weather, changing the paradigm of general aviation. And, the fun level would be off the chart. Wet dream babble. -- Jim Pennino Remove .spam.sux to reply. |
#24
|
|||
|
|||
How high can you fly?
Jim Logajan wrote:
Mark wrote: I keep running across new technologies and it takes time to come up with hard data and numbers that would allow me or anyone else to tell you what the new batteries weigh or what their energy density and durations are. I'm trying to point out that some of us have some of idea of what is possible within the next 10 years and what the ultimate physical limits are of energy density. Wikipedia has a table of energy densities for several battery technologies compared with traditional energy storage: http://en.wikipedia.org/wiki/Energy_density So far as I can tell it appears roughly correct. Avgas has an energy density of ~44MJ/kg. The best _emerging_ battery technology has an energy density of ~3.6MJ/kg. Ground vehicles can still be useful with low energy densities, but aircraft rapidly decline in utility. Put another way, airlines will be flying jets burning jet fuel for the forseeable future. The only aviation market I can see for electric airplanes, if batteries ever get good enough and cheap enough, is for self launched gliders. -- Jim Pennino Remove .spam.sux to reply. |
#26
|
|||
|
|||
How high can you fly?
Mark wrote:
On Sun, 19 Sep 2010 14:44:28 -0000, wrote: Jim Logajan wrote: Mark wrote: I keep running across new technologies and it takes time to come up with hard data and numbers that would allow me or anyone else to tell you what the new batteries weigh or what their energy density and durations are. I'm trying to point out that some of us have some of idea of what is possible within the next 10 years and what the ultimate physical limits are of energy density. Wikipedia has a table of energy densities for several battery technologies compared with traditional energy storage: http://en.wikipedia.org/wiki/Energy_density So far as I can tell it appears roughly correct. Avgas has an energy density of ~44MJ/kg. The best _emerging_ battery technology has an energy density of ~3.6MJ/kg. Ground vehicles can still be useful with low energy densities, but aircraft rapidly decline in utility. Put another way, airlines will be flying jets burning jet fuel for the forseeable future. The only aviation market I can see for electric airplanes, if batteries ever get good enough and cheap enough, is for self launched gliders. Doesn't surprise me, you have no vision. Most people don't which is why I am wealthy beyond your imagination. Get on board. I can make you loads of money. You could afford to buy a hat for your pinhead. Mark Of The Financial World More like Mark the babbling child-man. -- Jim Pennino Remove .spam.sux to reply. |
#27
|
|||
|
|||
How high can you fly?
|
#28
|
|||
|
|||
How high can you fly?
On Sun, 19 Sep 2010 17:31:59 -0500, Jim Logajan wrote:
While I think Mark is starry eyed (at best,) If starry eyed means delusional fukknutzoind, yeah, you got it. -- |
#29
|
|||
|
|||
How high can you fly?
Jim Logajan wrote:
wrote: Electric airplanes are not and will not be superior to ICE airplanes at any altitude any time in the foreseeable future. While I think Mark is starry eyed (at best,) you are technically mistaken in the above assertion because in fact electric airplanes (actually solar- electric airplanes) hold some world records: When the solar-electric "Pathfinder" reached 80,000 ft in 1999 it set the altitude record for highest altitude flown by prop-driven aircraft. When the solar-electric "Helios" reached 96,863 ft in 2001 it set the altitude record for highest altitude flown by non-rocket powered aircraft. When the solar-electric "Zepher" stayed aloft for for over 2 weeks in 2010, it set the endurance record for unmanned aircraft. The common element of these is "solar-electric". None of them would have been possible with batteries. They could not have gotten off the ground had they used batteries. None of them would have been plausibly accomplished with internal (or external) combustion engines. The latter gasp for breath at high altitudes. So electric (specifically solar-electric) is indeed superior for certain applications. Just not general aviation. They hold records for R/C airplanes. None of them had a human, or anything alive, on board. One off research prototypes can be interesting, but that's about it. -- Jim Pennino Remove .spam.sux to reply. |
#30
|
|||
|
|||
How high can you fly?
Mark opined
Ok, it's the year 2016. You are in a little Cessna 150. You're plane isn't pressurized because it will implode, so you're wearing a pressurized body suit. You have an oxygen mask. You plane is powered by a very powerful brushless electric motor supplied by a 20lb carbon nanotube source that is basically limitless. Your powerplant is equivalent to 700hp in an LSA. The electric motor and cabin are heated. How high can you fly? 95,000ft? This will soon be a real consideration. I don't have the figures available at the moment, but I can tell you what to look for and what to do. Find the Vs for a C152. Find the Mmo, likely about M.75. Your max altitude is where the true Vs == Mmo. -ash Elect Cthulhu! Vote the greater evil. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Apollo 13 pix last batch includes .par2s - "Apollo 13 Saturn V with boilerplate spacecraft during transfer move from High Bay 2 to High Bay 3 ap13-trfr-noID.jpg" yEnc (1/1) [90K] | hielan' laddie | Aviation Photos | 0 | September 12th 08 03:17 PM |
Apollo 13 pix last batch includes .par2s - "Apollo 13 Saturn V with boilerplate spacecraft during transfer move from High Bay 2 to High Bay 3 ap13-rollaround2-noID.jpg" yEnc (1/1) [97K] | hielan' laddie | Aviation Photos | 0 | September 12th 08 03:17 PM |
Apollo 13 pix last batch includes .par2s - "Apollo 13 Saturn V with boilerplate spacecraft during transfer move from High Bay 2 to High Bay 3 ap13-KSC-69P-684.jpg" yEnc (1/1) [109K] | hielan' laddie | Aviation Photos | 0 | September 12th 08 03:17 PM |
Apollo 13 pix last batch includes .par2s - "Apollo 13 Saturn V with boilerplate spacecraft during transfer move from High Bay 2 to High Bay 3 ap13-KSC-69P-683.jpg" yEnc (1/1) [121K] | hielan' laddie | Aviation Photos | 0 | September 12th 08 03:17 PM |
IVO pireps wanted.. high performance/high speed... | Dave S | Home Built | 8 | June 2nd 04 04:12 PM |