Engine weight and reducing it
04-08-2007 | 08:13 AM
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From: Milwaukee,
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Engine weight and reducing it
Engine weight could be reduced by using Magnesium for the crankcase and Titanium for some of the internal steel parts and screws and plastic carburetor bodies. All these things have all ready been done by one or more engine makers but as far as I know all of these features have not been done together on one engine.
Just think what a BME 115 would weigh if it had all these features specially if you could put a Titanium crankshaft in it.
Food for thought.
WRK
Just think what a BME 115 would weigh if it had all these features specially if you could put a Titanium crankshaft in it.
Food for thought.
WRK
04-08-2007 | 10:33 AM
#3
RE: Engine weight and reducing it
Who knows, by then we might have a complete polymer based engine, powerful and as light as a feather. Just look at what is happening in the hand gun arena these days.
Karol
Karol
04-08-2007 | 02:17 PM
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RE: Engine weight and reducing it
The current crop of engines could be lightened but it is too labor intensive. Titanium is practical for prop studs and fasteners but will only save about an ounce at the most. Magnesium will save weight over an aluminum casting but not over a carefully machined aluminum case. At this point there is little that can be done that will not add considerably to the price of an engine. There is some low hanging fruit to be picked in our carburetors, a (cheap) plastic Walbro would save more than expensive titanium. Engine weight should not be considered until ALL metal parts on the airframe and exhaust have been substituted with composites, otherwise your spending a dollar to save a dime.
04-08-2007 | 03:20 PM
#7
RE: Engine weight and reducing it
I'm no expert in metalurgy (sp?), but isn't titanium brittle? I might be wrong, but I've heard people say not to use the titanium axles because they are brittle. I would think you wouldn't want a brittle crankshaft or rod.
If titanium is brittle, then you wouldn't want to use it for prop hub bolts. Your not supposed to use stainless for prop hub bolts and firewalls because it's too brittle.
Why not make a CF crankcase with sleeve inserts where bearings must be pressed in? Or whatever? I would think a CF crankcase would be fairly light.
Most of the current magnesium cases are cast. I've seen quite a few on conversion engines. I really couldn't tell you what current production engines had magnesium cases. It's been said that a cast magnesium case is lighter than a cast aluminum case. AND it's been said that a machined aluminum case could be as light as a cast magnesium case. So, it stands to reason, with me, that a cast case is heavier than a machined case. Why not machine a case from magnesium? Wouldn't that be light? I have no idea what it would cost. I'll bet that as soon as the magnesium wholesalers figure out there is a demand for it--the price will go up.
We probably have a surplus of it on hand right now and they can't give it away, but soon as they find out they can make a buck--they'll be making 100 bucks for it instead. Speculation...
I think that it would be neat to see someone come up with an engine thats really ahead of it's time and innovative. Something that will have all of us going [X(]
I'll gaurantee ya something right now--and I'll stand by this untill I'm either proven right or end up with egg on my face.
It's gonna be EXPENSIVE
If titanium is brittle, then you wouldn't want to use it for prop hub bolts. Your not supposed to use stainless for prop hub bolts and firewalls because it's too brittle.
Why not make a CF crankcase with sleeve inserts where bearings must be pressed in? Or whatever? I would think a CF crankcase would be fairly light.
Most of the current magnesium cases are cast. I've seen quite a few on conversion engines. I really couldn't tell you what current production engines had magnesium cases. It's been said that a cast magnesium case is lighter than a cast aluminum case. AND it's been said that a machined aluminum case could be as light as a cast magnesium case. So, it stands to reason, with me, that a cast case is heavier than a machined case. Why not machine a case from magnesium? Wouldn't that be light? I have no idea what it would cost. I'll bet that as soon as the magnesium wholesalers figure out there is a demand for it--the price will go up.
We probably have a surplus of it on hand right now and they can't give it away, but soon as they find out they can make a buck--they'll be making 100 bucks for it instead. Speculation...I think that it would be neat to see someone come up with an engine thats really ahead of it's time and innovative. Something that will have all of us going [X(]
I'll gaurantee ya something right now--and I'll stand by this untill I'm either proven right or end up with egg on my face.
It's gonna be EXPENSIVE
04-08-2007 | 05:28 PM
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From: Riverton,
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RE: Engine weight and reducing it
So were going to have a BME that weighs 3 lbs instead of 4.2... its going to coast $2000 instead of $1200
Of course then you have to add another 1.2lb of lead to the nose to make it balance[:@]
Of course then you have to add another 1.2lb of lead to the nose to make it balance[:@]
04-08-2007 | 05:31 PM
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RE: Engine weight and reducing it
Of course then you have to add another 1.2lb of lead to the nose to make it balance
if lighter motors become the trend the planes will be build to balance more toward todays engine as they use to be back with hanging a sledge hammer motor of yester year
04-08-2007 | 10:54 PM
#11
RE: Engine weight and reducing it
ORIGINAL: Rcpilet
I'm no expert in metalurgy (sp?), but isn't titanium brittle? I might be wrong, but I've heard people say not to use the titanium axles because they are brittle. I would think you wouldn't want a brittle crankshaft or rod.
If titanium is brittle, then you wouldn't want to use it for prop hub bolts. Your not supposed to use stainless for prop hub bolts and firewalls because it's too brittle.
Why not make a CF crankcase with sleeve inserts where bearings must be pressed in? Or whatever? I would think a CF crankcase would be fairly light.
Most of the current magnesium cases are cast. I've seen quite a few on conversion engines. I really couldn't tell you what current production engines had magnesium cases. It's been said that a cast magnesium case is lighter than a cast aluminum case. AND it's been said that a machined aluminum case could be as light as a cast magnesium case. So, it stands to reason, with me, that a cast case is heavier than a machined case. Why not machine a case from magnesium? Wouldn't that be light? I have no idea what it would cost. I'll bet that as soon as the magnesium wholesalers figure out there is a demand for it--the price will go up. We probably have a surplus of it on hand right now and they can't give it away, but soon as they find out they can make a buck--they'll be making 100 bucks for it instead. Speculation...
I think that it would be neat to see someone come up with an engine thats really ahead of it's time and innovative. Something that will have all of us going [X(]
I'll gaurantee ya something right now--and I'll stand by this untill I'm either proven right or end up with egg on my face.
It's gonna be EXPENSIVE
I'm no expert in metalurgy (sp?), but isn't titanium brittle? I might be wrong, but I've heard people say not to use the titanium axles because they are brittle. I would think you wouldn't want a brittle crankshaft or rod.
If titanium is brittle, then you wouldn't want to use it for prop hub bolts. Your not supposed to use stainless for prop hub bolts and firewalls because it's too brittle.
Why not make a CF crankcase with sleeve inserts where bearings must be pressed in? Or whatever? I would think a CF crankcase would be fairly light.
Most of the current magnesium cases are cast. I've seen quite a few on conversion engines. I really couldn't tell you what current production engines had magnesium cases. It's been said that a cast magnesium case is lighter than a cast aluminum case. AND it's been said that a machined aluminum case could be as light as a cast magnesium case. So, it stands to reason, with me, that a cast case is heavier than a machined case. Why not machine a case from magnesium? Wouldn't that be light? I have no idea what it would cost. I'll bet that as soon as the magnesium wholesalers figure out there is a demand for it--the price will go up.
We probably have a surplus of it on hand right now and they can't give it away, but soon as they find out they can make a buck--they'll be making 100 bucks for it instead. Speculation...I think that it would be neat to see someone come up with an engine thats really ahead of it's time and innovative. Something that will have all of us going [X(]
I'll gaurantee ya something right now--and I'll stand by this untill I'm either proven right or end up with egg on my face.
It's gonna be EXPENSIVE
The CF crankcase could be done, but a well designed (that is, finite element analysis, serious test program to find weaknesses, etc.) magnesium one should be equal or very close and much easier to produce in quantity.
The use of magnesium in model aircraft engine will have NO effect at all on the world supply of a commonly used material like magnesium.
Very few people seem to realize we are dealing with dinosaurs for engines. They are air-cooled two strokes with carburators. This technology has been mature for a lot of years. Innovation now comes in small changes to porting for better/more power and clever packaging to optimize the engine for our uses.
You would be correct, any big weight savings will be very costly by the pound. More people should learn to build light airframes before worrying about saving a bit on the engine.
Mark
