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nuckolls.bob(at)aeroelect
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 Posted: Tue Jul 14, 2020 1:57 pm Post subject: Premature EarthX death? |
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At 11:01 AM 7/14/2020, you wrote:
| Quote: | | Bob, while I cannot agree with you about the importance of 10 lbs. additional useful load . . . |
Can you articulate the 'usefulness' in numbers? "Useful load" is
an arbitrary number derived from a host of design goals,
validated by very demanding flight testing and finally
holy-watered by someone who may not even have a pilot's
license much less practical experience in light plane
operations.
A delta-weight of 10 pounds on performance in a 1600 to
1800 pound airplane is undetectable by contemporary measurement
techniques. How many OBAM aircraft owners routinely
push the envelope for service ceiling, time to
climb, take off roll, etc. etc?
| Quote: | I do think you are onto something with the LiFePO4 friendly electrical system.
Builders could then choose any appropriate off the shelf battery, or even build
their own. What are some of the features that an LiFePO4 friendly system would have? |
BMS features are part of the ship's electrical
system including:
Over discharge disconnect (open the battery contactor)
Over current disconnect ( ditto )
Over voltage protection (already part of every thoughtful
system).
Cell balancing (not sure this is even called for
in assemblages of quality cells
that are not routinely deep
discharged . . . looking to clarify
that)
Recharge rate
Management (easily added to the duties of an
agile voltage regulator).
The benefits of such a system may extend past
the weight thingy . . . suppose you could stuff
a battery space with the SAME weight of lithium
as the removed SLVA and enjoy phenomenal alternator-
out endurance in electrically dependent engines?
These are things that come to mind the soonest . . . no
doubt there are others.
For a century we have been putting 'round' batteries
into systems DESIGNED with 'round' holes. I'm thinking
that with rather rudimentary design changes we can
craft a system that readily accepts bare-foot LiFePO4
arrays that wouldn't insult an SVLA battery either.
Bob . . .
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echristley(at)att.net
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| Posted: Tue Jul 14, 2020 2:56 pm Post subject: Premature EarthX death? |
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On Tuesday, July 14, 2020, 5:58:24 PM EDT, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:
> Can you articulate the 'usefulness' in numbers?
I can. My airplane tops out at 1320. There is a whole category of airplanes with that limitation now. Having made an arguably poor decision to use an engine that is on the heavy side, any extra weight in the nose comes with a corresponding requirement to add even more weight in the rear. 10 will get you 20, in other words.
The plane weighs 800, and I'm hitting the scales at 270 nowadays. if a 130lb passenger joins me, I can't use my full 22gal of fuel capacity, and we can't carry any luggage.
It's not that the 10lbs is so heavy in relation to the plane. It's that it is heavy in relation to what you have left in the budget.
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kenryan
Joined: 20 Oct 2009
Posts: 429
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| Posted: Tue Jul 14, 2020 4:22 pm Post subject: Premature EarthX death? |
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Can you articulate the 'usefulness' in numbers?
I could try, but I would fail miserably. Logically I understand that 10 pounds added to the gross is unlikely to cause me to hit the spruce tree on takeoff. But in reality, I know that decisions about what to take and what to leave are necessary all the time.
On Tue, Jul 14, 2020 at 2:03 PM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 11:01 AM 7/14/2020, you wrote:
| Quote: | | Bob, while I cannot agree with you about the importance of 10 lbs. additional useful load . . . |
Can you articulate the 'usefulness' in numbers? "Useful load" is
an arbitrary number derived from a host of design goals,
validated by very demanding flight testing and finally
holy-watered by someone who may not even have a pilot's
license much less practical experience in light plane
operations.
A delta-weight of 10 pounds on performance in a 1600 to
1800 pound airplane is undetectable by contemporary measurement
techniques. How many OBAM aircraft owners routinely
push the envelope for service ceiling, time to
climb, take off roll, etc. etc?
| Quote: | I do think you are onto something with the LiFePO4 friendly electrical system.
Builders could then choose any appropriate off the shelf battery, or even build
their own. What are some of the features that an LiFePO4 friendly system would have? |
BMS features are part of the ship's electrical
system including:
Over discharge disconnect (open the battery contactor)
Over current disconnect ( ditto )
Over voltage protection (already part of every thoughtful
system).
Cell balancing (not sure this is even called for
in assemblages of quality cells
that are not routinely deep
discharged . . . looking to clarify
that)
Recharge rate
Management (easily added to the duties of an
agile voltage regulator).
The benefits of such a system may extend past
the weight thingy . . . suppose you could stuff
a battery space with the SAME weight of lithium
as the removed SLVA and enjoy phenomenal alternator-
out endurance in electrically dependent engines?
These are things that come to mind the soonest . . . no
doubt there are others.
For a century we have been putting 'round' batteries
into systems DESIGNED with 'round' holes. I'm thinking
that with rather rudimentary design changes we can
craft a system that readily accepts bare-foot LiFePO4
arrays that wouldn't insult an SVLA battery either.
Bob . . .
|
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http://www.matronics.com/Navigator?AeroElectric-List |
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