Stupid hp to thrust question

Does a prop turning at 2300 rpm on a 150hp motor produce more thrust than a
prop spinning 2300 rpm on a 100 hp motor ?

"Mark" wrote in message
...
Does a prop turning at 2300 rpm on a 150hp motor produce more thrust than
a
prop spinning 2300 rpm on a 100 hp motor ?

I'm no authority on the subject, mind you, but it seems you get more thrust
from the more powerful engine because it will turn a prop with more pitch,
thus moves more air, thus more bite. Thus more thrust.

On Thu, 4 Dec 2003 20:24:00 -0500, "Mark" wrote:

Does a prop turning at 2300 rpm on a 150hp motor produce more thrust than a
prop spinning 2300 rpm on a 100 hp motor ?
+++++++++++++++++++++

Theoretically speaking -

If the props are identical....
so is the thrust on the test stand.


Barnyard BOb --
If I'm wrong, never mind.

Assuming both engines are producing the same torque at that rpm, then yes.
Torque x RPM = horsepower. Note: the props will not be both the same
diameter and pitch.
Stu Fields
"RR Urban" wrote in message
...
On Thu, 4 Dec 2003 20:24:00 -0500, "Mark" wrote:

Does a prop turning at 2300 rpm on a 150hp motor produce more thrust than
a
prop spinning 2300 rpm on a 100 hp motor ?
+++++++++++++++++++++

Theoretically speaking -

If the props are identical....
so is the thrust on the test stand.


Barnyard BOb --
If I'm wrong, never mind.

On 04 Dec 2003 04:24 PM, Mark posted the following:
Does a prop turning at 2300 rpm on a 150hp motor produce more thrust
than a prop spinning 2300 rpm on a 100 hp motor ?

Yes, unless the 150hp motor is an automotive engine, in which case
bolting a prop to it will cause it to violently self destruct before
reaching 2300rpm. 8^P

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

Mark wrote:
Does a prop turning at 2300 rpm on a 150hp motor produce more thrust than a
prop spinning 2300 rpm on a 100 hp motor ?




Assuming the same prop on both engines, then no.

A spinning prop produces thrust by throwing air backwards. Based upon
pitch, diameter and airfoil design, a given prop can throw a given
amount of air at a given RPM. It takes a specific amount of power for
the prop to do that.

If the 150hp motor is at full throttle, then the 100hp motor won't be
able to turn the prop at 2300. If the 100hp can turn at 2300, then a
150hp engine will be under-propped with that propeller and will easily
redline (either that or the 150hp engine isn't producing 100hp).

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

people sure like to over think things. The same prop can be put on any
engine of any horse power and if it is turned 2300 rpm then the thrust is
the same.

--
Have a good day and stay out of the trees!
See ya on Sport Aircraft group
http://groups.yahoo.com/group/Sport_Aircraft/

Flying Gators annual Fly-in
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"Gilan" wrote ...
people sure like to over think things. The same prop can be put on any
engine of any horse power and if it is turned 2300 rpm then the thrust is
the same.

Not necessarily. If one of the engines has a larger frontal area then part
of the flow will be blocked and that engine/prop will produce less thrust.
The extreme example is the engine that's larger than the prop diameter.

Rich

there you go thinking again.
you just added something into the question that wasn't there
Just stick to the original question and the answer is still the same.

--
Have a good day and stay out of the trees!
See ya on Sport Aircraft group
http://groups.yahoo.com/group/Sport_Aircraft/

In article , Mark says...

Does a prop turning at 2300 rpm on a 150hp motor produce more thrust than a
prop spinning 2300 rpm on a 100 hp motor ?

If it's the same prop and it turns 2300 on a 150 hp engine the 100hp engine
won't have the power to turn it 2300. If it turns 2300 on the 100 hp engine then
the 150 hp engine will over rev it and run away the prop. At 2300 rpm the prop
will produce the same thrust regardless of engine but the 150 hp engine would
really like a bigger prop to use the remaining 50 hp.

see ya Chuck (ain't no free ride in airplanes) S