Thermals and Horsepower

One horsepower is defined as lifting 550 pounds one foot in one second.


So, if were climbing at an average of 300 FPM (5 fps)in a two place
ship weighing 1100 pounds ... can we say we are
extracting/consuming/obtaining 10 HP from the thermal ...

KK

Ok, I'll bite...

Would it be the same amount of horsepower if spread
over a two-place ship's wing-span...as it would if
the 1100lbs was a lead weight?



At 18:30 08 January 2005, Ken Kochanski Kk wrote:
One horsepower is defined as lifting 550 pounds one
foot in one second.


So, if were climbing at an average of 300 FPM (5 fps)in
a two place
ship weighing 1100 pounds ... can we say we are
extracting/consuming/obtaining 10 HP from the thermal
...

KK

I'm not an engineer, but I don't think it makes a diference.

I think HP is just a measure of work ... like weight lifted x distance
in y seconds as defined.


Stewart Kissel wrote:
Ok, I'll bite...

Would it be the same amount of horsepower if spread
over a two-place ship's wing-span...as it would if
the 1100lbs was a lead weight?



At 18:30 08 January 2005, Ken Kochanski Kk wrote:
One horsepower is defined as lifting 550 pounds one
foot in one second.


So, if were climbing at an average of 300 FPM (5 fps)in
a two place
ship weighing 1100 pounds ... can we say we are
extracting/consuming/obtaining 10 HP from the thermal
...

KK

Ken Kochanski (KK) wrote:
I'm not an engineer, but I don't think it makes a diference.

I think HP is just a measure of work ... like weight lifted x distance
in y seconds as defined.

Not quite:
- Weight lifted x distance is "work". The amount of work
is the same, regardless how long it takes to do the lifting.
- When you introduce the time element: work per time unit,
that is called "power".
HP is a unit for measuring power.
CV

OK ... I have been trying to understand this better as someone recently
asked about the energy we used to soar ... I could explain how we
thermaled and how we converted altitude for distance, etc., but
couldn't convert that into some statement about horsepower or watts,
etc. So, looking at it another way ... if we have to climb, let's say
30,000' to get around a task ... how do you describe the total energy
involved ... both as a potential ... and also as a reflection of energy
expended if you lets say burn off 30K feet at an average speed of 60
mph in 2 hours.

KK
Running On Entropy (or something else ...)



CV wrote:
Ken Kochanski (KK) wrote:
I'm not an engineer, but I don't think it makes a diference.

I think HP is just a measure of work ... like weight lifted x
distance
in y seconds as defined.

Not quite:
- Weight lifted x distance is "work". The amount of work
is the same, regardless how long it takes to do the lifting.
- When you introduce the time element: work per time unit,
that is called "power".
HP is a unit for measuring power.
CV

HP is a unit for measuring power.

Yes but kW is the right one.

:-)

Ian

Earlier, Ken Kochanski (KK) wrote:

...I think HP is just a measure of work...

Well, in a manner of speakin', yeah!


Bob K.
http://www.hpaircraft.com

What do you expect from a Psych major ... :-)

I was trying to understand what the energy numbers involved in XC
soaring were ... to give a common sense explanation on the SRA page
(http://sailplane-racing.org/) ... the visual images are not too
exciting, however.

We pull 15 HP out of a thermal while climbing .... so is my 'exciting'
visual a 15 HP John Deere Lawn Tractor driving up a vertical wall.

And if an 800 pound sailplane needs about 30000' feet to get around a
racing course ... I think the energy used translates to less then 10
kwh ... well, if that is correct ... I guess I can supply the
electricity needs of my house for a day or so.


KK

Hi Ken,

I think it's more like 14 HP, when a sink rate of 2 fps is included.

BTW, have you noticed when a large gaggle leaves the thermal, the thermal
gets stronger?

Bob

"Ken Kochanski (KK)" wrote in message
oups.com...
One horsepower is defined as lifting 550 pounds one foot in one second.


So, if were climbing at an average of 300 FPM (5 fps)in a two place
ship weighing 1100 pounds ... can we say we are
extracting/consuming/obtaining 10 HP from the thermal ...

KK

I have noticed them get weaker as ships enter ... i.e. when we just
find a weak thermal to save our butts and the gaggle then comes over
and squashes it. :-)


Bob Salvo wrote:
Hi Ken,

I think it's more like 14 HP, when a sink rate of 2 fps is included.

BTW, have you noticed when a large gaggle leaves the thermal, the
thermal
gets stronger?

Bob

"Ken Kochanski (KK)" wrote in message
oups.com...
One horsepower is defined as lifting 550 pounds one foot in one
second.


So, if were climbing at an average of 300 FPM (5 fps)in a two place
ship weighing 1100 pounds ... can we say we are
extracting/consuming/obtaining 10 HP from the thermal ...

KK