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
|
|||
|
|||
subaru diesel
On Tue, 25 Mar 2008 08:39:12 -0500, Barnyard BOb
wrote: Morgans" wrote: "Dale Scroggins" wrote It's going to need a starter; diesels are hard to hand prop. And the engine is not likely designed to handle thrust and gyroscopic loads. Many auto engine cranks have done well with these loads, and no extra help. Name 'em and define what you mean by 'no extra help'? and need for a well-supported prop shaft, a nose-piece casting with bearings and a prop shaft will be needed. Not a given, IMHO. YES.... 'a given' or something very close to one for safety sake. Wait until it is being used, and see how well it does, is my opinion. It will let us know, by how it does after it has been eXperimented with, I believe. You may be surprised. I might be, too. Until then, keep an open mind. Aw phoof! A promising answer or solution is always just around the corner. In the meantime, I guess you can fly around in a baloon filled with the hot air generated here! - Barnyard BOb - P.S. Morgans.... Dunt waist yer tyme tellin mee howe too speal balloon, o-kay? - Barnyard BOb- |
#22
|
|||
|
|||
subaru diesel
"Barnyard BOb" wrote Morgans.... Dunt waist yer tyme tellin mee howe too speal balloon, o-kay? O.K., but I thought you were going for baboon! ;-) -- Jim in NC |
#23
|
|||
|
|||
subaru diesel
On Tue, 25 Mar 2008 12:12:50 -0400, "Morgans"
wrote: "Barnyard BOb" wrote Morgans.... Dunt waist yer tyme tellin mee howe too speal balloon, o-kay? O.K., but I thought you were going for baboon! ;-) -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- If I was mean spirited..... you would be corrrect. I would have called you a hot air BABOON! However, I'm still just the classic grouch, Jim!!!! Bless you and all the world's Corvairs. 8-) - Barnyard BOb - |
#24
|
|||
|
|||
subaru diesel
"Dale Scroggins" wrote in message
... "Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way D0t C0m wrote in message news:N6adnXfOAtwpgHXanZ2dnUVZ_sWdnZ2d@wideopenwest .com... ... Hmm. So the dozens of induction fires (some of which caused substantial damage) that I've witnessed over the years are just as likely with a diesel engine? Probably not, since there is no fuel in the induction system. 10. Props are more efficient at lower RPMs, usually. Diesels have torque to turn props slow in cruise, like a turboprop (1800-1900 RPM), giving maybe another 5% efficiency gain, and a quieter cabin to boot. Depends on how the engine was designed, not how the fuel is ignited. Hmm again. So the burn characteristics of the fuel, the ability to inject additional fuel after initiation of combustion, and the surplus of available oxygen have no impact on engine torque curves? On the contrary. The inabilty to mix the fuel with the air is the reason that typical diesel torque curves flatten out at low speeds - a gas engine can better use the air and generates more torque at the higher speeds. So the TENDANCY is to select bore/stroke ratio's and displacements that favor lower speeds in diesels. But there are lots of exceptions. .. Wasn't the prospect of a relatively light weight diesel available to homebuilders the point of this thread? No one knows if Subaru's diesel will match the durability of a current-production avgas engine. However, newer diesel injection methods have helped reduce internal engine forces, so durable, light diesel engines are on the horizon. What do you see as the advantages of diesel aircraft engines? Primary advantage is fuel consumption - higher compression, lower pumping losses (minor benifit for aircraft) and reduced heat loss due to the stratified nature of the combustion all help to improve efficiency. Increased fuel density also gives a boost to "miles per gallon" - but for aircraft it's about "miles per pound". Primary disadvantage is power to weight. Diesels are typically smoke limited - they can't use all the air, so the power is limited - that's why turbos are so popular on diesels. The higher combustion pressures also require a heavier block and a heavier bottom end which, well, being heavier, adds weight. Secondary advantage is no ignition system. Secondary disadvantage is a somewhat fussy fuel system (and, with a common rail system, you are just as reliant on electricity as an electronic fuel injected gas engine). Probably less of a problem for aircraft use when compared to small marine applications - do a search on "fuel polishing"... FWIW - look for the press propaganda on Ford's "Eco-Boost" - turbo charged, direct injection, spark ignited gas - looks like they are shooting to get closer to diesel fuel economy without the cost (diesel aftertreatment is REAL expensive at the lower emission standards). Improving power to weight lets them downsize the engine, down size vehicle componants, etc. Of course, one could say that direct injection gasoline has all the disadvantages of both gasoline and diesel engines. ;-) -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
#25
|
|||
|
|||
subaru diesel
"Blueskies" wrote in message
t... ... Why any sort of reciprocating engine?...small turboprops would be the best solution of they can get the mass fuel flow problems resolved... Nothing like the laws of thermodynamics and material limitations to ruin a good party. -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
#26
|
|||
|
|||
subaru diesel
"Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way D0t C0m wrote in message
... "Dale Scroggins" wrote in message ... "Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way D0t C0m wrote in message news:N6adnXfOAtwpgHXanZ2dnUVZ_sWdnZ2d@wideopenwest .com... ... ... What do you see as the advantages of diesel aircraft engines? Primary advantage is fuel consumption - higher compression, lower pumping losses (minor benifit for aircraft) and reduced heat loss due to the stratified nature of the combustion all help to improve efficiency. Increased fuel density also gives a boost to "miles per gallon" - but for aircraft it's about "miles per pound". Oh, I forgot, they can run on Jet fuel if the injector pump will tolerate it... On the downside, diesel fuel is good for growing algae, dunno about jet fuel - but given the number of hanger queens at the typical airport, I assume we will find out when diesels make a dent in the aircraft market. -- Geoff The Sea Hawk at Wow Way d0t Com remove spaces and make the obvious substitutions to reply by mail When immigration is outlawed, only outlaws will immigrate. |
#27
|
|||
|
|||
subaru diesel
"Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way D0t C0m wrote Nothing like the laws of thermodynamics and material limitations to ruin a good party. Yep. Small turbine engines are not fuel efficient, and yet they are expensive. The materials are exotic, and so are the methods that have to be used to construct the engine. The gains that have been made with small turbines are amazing enough to me, but they still have not gone to where they need to be, to be practical. That said, I still want one of those rigid skydiving wings, with the 4 pack of model jet engines! What a rush that HAS to be! -- Jim in NC |
#28
|
|||
|
|||
subaru diesel
"Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way D0t C0m wrote in message news:mLWdneP7Q9QVCXTanZ2dnUVZ_sqinZ2d@wideopenwest .com... Primary advantage is fuel consumption - higher compression, lower pumping losses (minor benifit for aircraft) and reduced heat loss due to the stratified nature of the combustion all help to improve efficiency. Increased fuel density also gives a boost to "miles per gallon" - but for aircraft it's about "miles per pound". Oh, I forgot, they can run on Jet fuel if the injector pump will tolerate it... AFAIK, the newly demanded ultra low sulphur diesel fuel is nasty stuff for the pumps, because the hurriedly implemented refining process also strips lubricants from the fuel. I have no idea whether this will be a continuing problem or whether other processes maintain the lubricity of the fuel. On the downside, diesel fuel is good for growing algae, dunno about jet fuel - but given the number of hanger queens at the typical airport, I assume we will find out when diesels make a dent in the aircraft market. I don't know about the kerosene based jet fuel sold here in the U.S., but some of the foreign stuff is (or at least was) a feeding ground for micro-organisms. The Eastern Airlines L-1011 that went down in the Florida Everglades some years ago was apparently full of the stuff after having been previously refuelled in Israel. BTW, I'm glad someone remembers what a hangar queen is. ;-)) Peter |
#29
|
|||
|
|||
subaru diesel
Morgans wrote:
"Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way D0t C0m wrote Nothing like the laws of thermodynamics and material limitations to ruin a good party. Yep. Small turbine engines are not fuel efficient, and yet they are expensive. The materials are exotic, and so are the methods that have to be used to construct the engine. The gains that have been made with small turbines are amazing enough to me, but they still have not gone to where they need to be, to be practical. That said, I still want one of those rigid skydiving wings, with the 4 pack of model jet engines! What a rush that HAS to be! If you got the money, I got the time! -- (remove the X to email) It's never too late to be the person you might have been. George Elliot |
#30
|
|||
|
|||
subaru diesel
cavelamb himself wrote:
Morgans wrote: "Capt. Geoffrey Thorpe" The Sea Hawk At Wow Way D0t C0m wrote Nothing like the laws of thermodynamics and material limitations to ruin a good party. Yep. Small turbine engines are not fuel efficient, and yet they are expensive. The materials are exotic, and so are the methods that have to be used to construct the engine. The gains that have been made with small turbines are amazing enough to me, but they still have not gone to where they need to be, to be practical. That said, I still want one of those rigid skydiving wings, with the 4 pack of model jet engines! What a rush that HAS to be! If you got the money, I got the time! But YOU are doing the first flight! |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
New diesel engine from Subaru... | [email protected] | Home Built | 16 | March 21st 08 02:31 AM |
Diesel Jodel information..........and .........diesel plane groups | Roland M | Owning | 1 | January 4th 04 04:04 AM |
Diesel engines for Planes Yahoo Group Jodel Diesel is Isuzu Citroen Peugeot | Roland M | Home Built | 3 | September 13th 03 12:44 AM |
Diesel engines for Planes Yahoo Group Jodel Diesel is Isuzu Citroen Peugeot | Roland M | General Aviation | 2 | September 13th 03 12:44 AM |
Diesel engines for Planes Yahoo Group Jodel Diesel is Isuzu Citroen Peugeot | Roland M | Rotorcraft | 2 | September 13th 03 12:44 AM |