Stupid hp to thrust question

[Mark]

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 ?

[Larry Smith]

"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.

[RR Urban]

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.

[Stu Fields]

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.

[Del Rawlins]

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/

[Ernest Christley]

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

[Gilan]

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
http://www.mitchellwing.com/flying_gators_annual_fly.htm

[Richard Isakson]

"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

[Gilan]

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/

[ChuckSlusarczyk]

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

[Toks Desalu]

He got a point!

"Gilan" > wrote in message
nk.net...
> 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/
>
>
>
>
>

[Orval Fairbairn]

In article >, "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 ?
>
>
>

Insufficient data!

Constant speed prop?
Manifold pressure?
Zero wind?
Same atmospheric conditions?

[Ron Wanttaja]

[Ron throws his oar in]

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 ?

Assuming the engines are mounted on a ground test stand, and the propellers
are "normal" (no paddlewheels, etc.):

If the props are identical fixed pitch propellers, the same thrust is
produced. Both engines are producing the same power.

If the engines are NOT producing the same power, it is because their
throttle positions and the propellers. Either may produce more thrust,
depending on the combination of the two parameters. For instance, the 150
HP engine could have controllable-pitch prop at flat pitch....it might turn
2300 with the throttle barely cracked.

If both engines are producing their rated horsepower, the 150 HP engine
produces more thrust. Its propeller must move more air in order to absorb
the higher power at the same RPM.

Ron Wanttaja

[RR Urban]

>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-
++++++++++++++++++

Smoooooch !


Barnyard BOb --
The more people I meet,
the more I luv my dawg,,,,
and George Carlin humor.

[Dan Thomas]

Ron Wanttaja > wrote in message >...
> [Ron throws his oar in]
>
> 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 ?
>
> Assuming the engines are mounted on a ground test stand, and the propellers
> are "normal" (no paddlewheels, etc.):
>
> If the props are identical fixed pitch propellers, the same thrust is
> produced. Both engines are producing the same power.
>
> If the engines are NOT producing the same power, it is because their
> throttle positions and the propellers. Either may produce more thrust,
> depending on the combination of the two parameters. For instance, the 150
> HP engine could have controllable-pitch prop at flat pitch....it might turn
> 2300 with the throttle barely cracked.
>
> If both engines are producing their rated horsepower, the 150 HP engine
> produces more thrust. Its propeller must move more air in order to absorb
> the higher power at the same RPM.
>
> Ron Wanttaja


Typical static thrust for the engines in light airplanes is around
three pounds per horsepower, IIRC. This figure will vary somewhat with
prop efficiency and rated RPM. A lower rated RPM for a given HP will
produce more thrust, as less of the energy is lost to prop blade drag.
An example of this is the Thielert Centurion diesel now STCd for
the Cessna 172 N and P models, among others. It produces 135 Hp at
2300 instead of the 160 at 2700 from the Lyc it replaces, yet the
performance doesn't suffer at all. Drag is about 28% less on 16% less
power. These are my rough calculations and I'm open to correction. Try
http://www.centurion-engines.com/
Turning an engine much faster to increase HP has been a standard
trick of both auto manufacturers and aircraft engine makers, but so
much of the increased HP just goes into making more noise, especially
when driving a prop.

Dan

[RobertR237]

In article
>, Orval
Fairbairn > writes:

>
>> 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 ?
>>
>>
>>
>
>Insufficient data!
>
>Constant speed prop?
>Manifold pressure?
>Zero wind?
>Same atmospheric conditions?
>
>

Where do you get insufficient data? Question does not indicate a different
prop turning on the two engines. "A" prop indicates the same prop used on two
different hp engines turning at the exact same RPM with no indicated
differences. The resulting thrust will be the same.


Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[RobertR237]

In article >, ChuckSlusarczyk
> writes:

>>
>>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
>
>

Ah Hell Chuck, you missed the point of the question here. The thrust produced
will remain the same in both instances regardless of the engine horsepower. If
indeed the 100hp engine is turning the prop at 2300 rpm and requires the full
100 hp to do so, the 150 hp engine is not producing full power to turn the
prop. A 1000 hp engine turning the same prop at the same rpm will still
produce the exact same thrust.


Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[ChuckSlusarczyk]

In article >, Dan Thomas says...
>
>> Turning an engine much faster to increase HP has been a standard
>trick of both auto manufacturers and aircraft engine makers, but so
>much of the increased HP just goes into making more noise, especially
>when driving a prop.

Unless you have a redrive installed so as to be able to use the additional hp.

Chuck S

[RobertR237]

In article >, "Morgans"
> writes:

>
>> Ah Hell Chuck, you missed the point of the question here.
>
>> Bob Reed
>
>I don't think the OP was asking a trick question. While you and I
>understand the relation between thrust and HP, I do not think the OP has a
>grasp on it. What was not said, was, "if I use the correct prop to get 2300
>RPM at full power, will the 100 HP and 150 HP engine have the same thrust?"
>
>On the other hand, I could be reading too much between the lines, and could
>be completely wrong. If so, "never mind" :-)
>--
>Jim in NC
>
>
>

Now that is an entirely different question and the answer is likewise entirely
different. I was not reading anything extra into the original question (for a
change) and the answer would be no difference.




Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[Morgans]

"RobertR237" > wrote

> Ah Hell Chuck, you missed the point of the question here.

> Bob Reed

I don't think the OP was asking a trick question. While you and I
understand the relation between thrust and HP, I do not think the OP has a
grasp on it. What was not said, was, "if I use the correct prop to get 2300
RPM at full power, will the 100 HP and 150 HP engine have the same thrust?"

On the other hand, I could be reading too much between the lines, and could
be completely wrong. If so, "never mind" :-)
--
Jim in NC

[ChuckSlusarczyk]

In article >, RobertR237 says...

>Ah Hell Chuck, you missed the point of the question here. The thrust produced
>will remain the same in both instances regardless of the engine horsepower. If
>indeed the 100hp engine is turning the prop at 2300 rpm and requires the full
>100 hp to do so, the 150 hp engine is not producing full power to turn the
>prop. A 1000 hp engine turning the same prop at the same rpm will still
>produce the exact same thrust.

Ah hell Bob,I guess I don't see what point I missed :-) Seems we're both saying
the same thing. Given it's the same prop on both engines and the prop is turning
2300 rpm it will always produce the same thrust at that rpm regardless .However
if you start to open the throttle the 1000 hp engine it will turn faster and
produce more thrust because it has the power to do so...But the prop will be
spinning faster than 2300 . Maybe I'm not understanding the question.

See ya

Chuck (time for Beany) S

[David O]

(RobertR237) wrote:

>Where do you get insufficient data? Question does not indicate a different
>prop turning on the two engines. "A" prop indicates the same prop used on two
>different hp engines turning at the exact same RPM with no indicated
>differences.

No, the query was ambiguous both semantically and in its technical
context. Evidence of the query's ambiguity is right in this thread,
where reasonable people took its meaning differently. Orval was
correct, "Insufficient data."

David O -- http://www.AirplaneZone.com

[RR Urban]

>>Where do you get insufficient data? Question does not indicate a different
>>prop turning on the two engines. "A" prop indicates the same prop used on two
>>different hp engines turning at the exact same RPM with no indicated
>>differences.
>
>No, the query was ambiguous both semantically and in its technical
>context. Evidence of the query's ambiguity is right in this thread,
>where reasonable people took its meaning differently. Orval was
>correct, "Insufficient data."
>
>David O --
+++++++++++++++++++++++++++++++++++++++

Where the hell is the poster of the original question?
Has he left town after all this scientific
and not so scientific commotion?

If not...
Maybe, he will rephrase his question so 'we' can
settle this once and for all and move on to solving
the rest of the world's less pressing problems. <g>

Barnyard BOb - with a mouse in his pocket

[RobertR237]

In article >, RR Urban >
writes:

>
>Where the hell is the poster of the original question?
>Has he left town after all this scientific
>and not so scientific commotion?
>
>If not...
>Maybe, he will rephrase his question so 'we' can
>settle this once and for all and move on to solving
>the rest of the world's less pressing problems. <g>
>
>Barnyard BOb - with a mouse in his pocket
>
>

What and end all this fun. ;-)


Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[RobertR237]

In article >, ChuckSlusarczyk
> writes:

>
>Ah hell Bob,I guess I don't see what point I missed :-) Seems we're both
>saying
>the same thing. Given it's the same prop on both engines and the prop is
>turning
>2300 rpm it will always produce the same thrust at that rpm regardless
>.However
>if you start to open the throttle the 1000 hp engine it will turn faster and
>produce more thrust because it has the power to do so...But the prop will be
>spinning faster than 2300 . Maybe I'm not understanding the question.
>
>See ya
>
>Chuck (time for Beany) S
>

Depends on rather you answer the question as written or read more into it.
Answering the question directly as written the answer is both would produce
exactly the same thrust. If the question however asked which was capable of
producing more thrust, the answer changes.

Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[David O]

RR Urban > wrote:

>Where the hell is the poster of the original question?
>Has he left town after all this scientific
>and not so scientific commotion?

I expect that "Mark" ) is sitting back enjoying the show.
BTW, of those who attempted to answer his question, yours was the best
IMHO -- it was concise, to the point, and included reasonably
sufficient conditions (identical props, test stand).

David O -- http://www.AriplaneZone.com

[PW]

To quote Bill Clinton, "It depends on what your definition of what thrust
is"? :)

Damn, I've never read so much BS for a simple question. :)

[RR Urban]

>>Where the hell is the poster of the original question?
>>Has he left town after all this scientific
>>and not so scientific commotion?
>
>I expect that "Mark" ) is sitting back enjoying the show.
>BTW, of those who attempted to answer his question, yours was the best
>IMHO -- it was concise, to the point, and included reasonably
>sufficient conditions (identical props, test stand).
>
>David O -- http://www.AriplaneZone.com
++++++++++++++++++++++++++++++++++

WoW....
Coming from you, this is quite a compliment.
Thank you.

FWIW....
I considered "insufficient data" immediately,
but that seemed a bit too cut and dried at
the time for my mental picture of "Mark"...
considering the way he framed his question..

It is my fondest hope that the various
replies have enriched him much more
than he might have expected. <g>


Barnyard BOb -- Merry Christmas to all

[ChuckSlusarczyk]

In article >, RobertR237 says...
>>
>Depends on rather you answer the question as written or read more into it.
>Answering the question directly as written the answer is both would produce
>exactly the same thrust. If the question however asked which was capable of
>producing more thrust, the answer changes.

Ahh so he says as the bulb lights and the dawn arises ...Now I see :-)

Chuck (I'm sliding on the ice) S

[RobertR237]

In article >, ChuckSlusarczyk
> writes:

>>Depends on rather you answer the question as written or read more into it.
>>Answering the question directly as written the answer is both would produce
>>exactly the same thrust. If the question however asked which was capable of
>>producing more thrust, the answer changes.
>
>Ahh so he says as the bulb lights and the dawn arises ...Now I see :-)
>
>Chuck (I'm sliding on the ice) S
>
>

I have been burned way too many times taking tests where I read more into the
question that was written. I gave an answer based on just that, nothing more,
nothing less. It does however go against my nature and I always want to dig
into the additional factors as one poster mentioned, adjustable pitch, etc.

Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[Mark]

Hi All, thanks for the responses, was not meant to be a trick question but
definately a newbie question. I was curious after reading about people using
mazda 13b engines for various homebuilts, and porting them, adding on
various components to boost the hp from 200 to 260+. Seems at a point that
it's overkill if the 200 hp engine is going to provide you with the needed
ponies and rpms to accomplish the same as the 260 hp engine. What would the
advantge be of having the extra horsepower ?

Thanks,

Mark


"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 ?
>
>
>

[RobertR237]

In article >, "Mark" > writes:

>
>Hi All, thanks for the responses, was not meant to be a trick question but
>definately a newbie question. I was curious after reading about people using
>mazda 13b engines for various homebuilts, and porting them, adding on
>various components to boost the hp from 200 to 260+. Seems at a point that
>it's overkill if the 200 hp engine is going to provide you with the needed
>ponies and rpms to accomplish the same as the 260 hp engine. What would the
>advantge be of having the extra horsepower ?
>
>Thanks,
>
>Mark
>
>

NOW you have asked the question the right way and will see some good answers.
The advantage of more horsepower is the capability of increased thrust, which
is not a factor of just the RPM but of the ability to convert the horsepower to
usable thrust using a prop geared to the output of the engine. Thrust is
created by the prop and is determined by the RPM of the prop, the length of the
blades, the number of blades and the pitch of the blades along with a host of
other factors. Assuming for one example the same number of blades, the same
RPM, the same length of blades, and other conditions for two engines and two
props, the higher horsepower engine will be able to turn a larger pitch prop
than will the lower horsepower engine and will produce more thrust.

Think of it the same way as a race care. The higher the horsepower available
from the engine, the higher the gear ratio that can be used and the faster the
top end speed.

PS: This is a simple answer to your question but many factors are involved.
The effort to increase a 200 hp engine to 260 hp may or may not be worth the
effort and the 30% increase in hp wil not produce an equilivent increase in
thrust or speed. I don't remember the formula for calculating the increase but
it is far less than anticipated.




Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[Eric Miller]

"RobertR237" > wrote in message
...
> PS: This is a simple answer to your question but many factors are
involved.
> The effort to increase a 200 hp engine to 260 hp may or may not be worth
the
> effort and the 30% increase in hp wil not produce an equilivent increase
in
> thrust or speed. I don't remember the formula for calculating the
increase but
> it is far less than anticipated.

Speed increases at about the cube root of the HP increase, so:

(260 / 200) ^ (1 / 3) = 1.091 or about 9% faster with 30% more HP

But other factors to consider are the increased weight of a larger engine,
the increased fuel burn, and the weight of that fuel.

Eric

[Orval Fairbairn]

In article >,
"Eric Miller" > wrote:

> "RobertR237" > wrote in message
> ...
> > PS: This is a simple answer to your question but many factors are
> involved.
> > The effort to increase a 200 hp engine to 260 hp may or may not be worth
> the
> > effort and the 30% increase in hp wil not produce an equilivent increase
> in
> > thrust or speed. I don't remember the formula for calculating the
> increase but
> > it is far less than anticipated.
>
> Speed increases at about the cube root of the HP increase, so:
>
> (260 / 200) ^ (1 / 3) = 1.091 or about 9% faster with 30% more HP
>
> But other factors to consider are the increased weight of a larger engine,
> the increased fuel burn, and the weight of that fuel.
>
> Eric
>
>

Extra horsepower converts directly into rate of climb, assuming the same
weight and airspeed. Fuel consumption rises approximately in proportion
to horsepower; stability decreases.

Other factors in boosting phenomenal horsepower out of small packages:

Increased thermal load
Increased stress on all parts of the engine
Some high RPM ranges may not yield usable thrust because the prop tips
are in the transonic range, where prop efficiency decreases greatly.

[nafod40]

RR Urban wrote:
> 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 ?

To paraphrase the question...

If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
lb bag, which bag is holding more crap?

[Russell Kent]

nafod40 wrote:

> RR Urban wrote:
> > 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 ?
>
> To paraphrase the question...
>
> If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
> lb bag, which bag is holding more crap?

OOooooooo..... *SO* close, and yet just off. I think you meant to say:
"If I put 100 lbs of crap in a 100 lb bag, and 100 lbs of crap in a 150 lb bag,
which bag holds more crap?"

Russell Kent

[Rich S.]

"Russell Kent" > wrote in message
...
> nafod40 wrote:
>
> OOooooooo..... *SO* close, and yet just off. I think you meant to say:
> "If I put 100 lbs of crap in a 100 lb bag, and 100 lbs of crap in a 150 lb
bag,
> which bag holds more crap?"

That's an easy one - A 150 lb (capacity) bag holds more crap than a 100 lb
(capacity) bag.

I think YOU meant to say, "If I put 100 lbs of crap in a 100 lb bag, and 100
lbs of crap in a 150 lb bag, Which bag contains more crap?"

Rich "150 lbs of crap in a 100 lb bag is known as a 'Blivet'". S.

[RobertR237]

In article >, nafod40 >
writes:

>>
>>>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 ?
>
>To paraphrase the question...
>
>If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
>lb bag, which bag is holding more crap?
>
>

Damn BOb, you sure are full of CRAP! ;-)))))

Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[Russell Kent]

"Rich S." wrote:

> "Russell Kent" > wrote in message
> ...
> > nafod40 wrote:
> >
> > OOooooooo..... *SO* close, and yet just off. I think you meant to say:
> > "If I put 100 lbs of crap in a 100 lb bag, and 100 lbs of crap in a 150 lb
> bag,
> > which bag holds more crap?"
>
> That's an easy one - A 150 lb (capacity) bag holds more crap than a 100 lb
> (capacity) bag.
>
> I think YOU meant to say, "If I put 100 lbs of crap in a 100 lb bag, and 100
> lbs of crap in a 150 lb bag, Which bag contains more crap?"
>
> Rich "150 lbs of crap in a 100 lb bag is known as a 'Blivet'". S.

Not so fast. If my eyes aren't deceiving me, the only change you made was
"contains" for "holds". English being an exceptionally slippery language, it
seems to me that those terms are synonymous. Makes it rather hard to give a
definitive answer to the original poster's question if we aren't clear on
whether "hold/contains" means "at the moment" or "at maximum capacity", which I
believe is the issue that nafod40 was attempting to illustrate with his
posting. I was only trying to show that nafod40's choice of numbers weren't
quite parallel to the original poster's question.

BTW, there's entirely too much crap in here. :-)

ob. aviation content: My Dad used to drop blivets from the B-52 he flew. :-)

Russell Kent

[Russell Kent]

Bob Reed wrote:

> Damn BOb, you sure are full of CRAP! ;-)))))

I'm sure NO ONE here, not even the crotchety old fool himself, will deny that BOb
is full of crap (sometimes), *BUT* it was nafod40 whom you (Bob Reed) quoted and
not BOb.

Russell Kent

[RR Urban]

>In article >, nafod40 >
>writes:
>
>>>
>>>>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 ?
>>
>>To paraphrase the question...
>>
>>If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
>>lb bag, which bag is holding more crap?
>>
>>
>
>Damn BOb, you sure are full of CRAP! ;-)))))
>
>Bob Reed
++++++++++++++++++++++++++++++++++++++++++

Whoa, Bob.

You have corn-fused me with somebody that gives a CRAP.
Neither my dog or I would care to be involved in this blivet* fiasco.

* blivet

/bliv'*t/ n. [allegedly from a World War II military term
meaning "ten pounds of manure in a five-pound bag"]


Barnyard BOb - -
The more people I meet,
the more I love my dog
and George Carlin humor.

[Rich S.]

"Russell Kent" > wrote in message
...
>
> Not so fast. If my eyes aren't deceiving me, the only change you made was
> "contains" for "holds". English being an exceptionally slippery language,
it
> seems to me that those terms are synonymous. Makes it rather hard to give
a
> definitive answer to the original poster's question if we aren't clear on
> whether "hold/contains" means "at the moment" or "at maximum capacity",
which I
> believe is the issue that nafod40 was attempting to illustrate with his
> posting. I was only trying to show that nafod40's choice of numbers
weren't
> quite parallel to the original poster's question.
>
> BTW, there's entirely too much crap in here. :-)
>
> ob. aviation content: My Dad used to drop blivets from the B-52 he flew.
:-)

Slippery? I won't go there. :^P

But I think "contains" is much more appropriate than "holds". Example - In
front of you are two empty sacks; one of 150 lbs capacity (assuming standard
crap mass/weight/volume/specific gravity) and another of 100 lbs capacity.
Which one "holds" more? Which one contains more? There's no correct answer -
it's just my opinion and probably stinks.

Aviation reply - No wonder the N. Vietnamese hated the Bee 52!!! Would that
be a weapon of Mass Corruption?

Rich S.

[RR Urban]

>Bob Reed wrote:
>
>> Damn BOb, you sure are full of CRAP! ;-)))))
>
>I'm sure NO ONE here, not even the crotchety old fool himself, will deny that BOb
>is full of crap (sometimes), *BUT* it was nafod40 whom you (Bob Reed) quoted and
>not BOb.
>
>Russell Kent
+++++++++++++++++++++++++++++++++++++++

When I go blind from one too many Muzzleloaders....
You can officially be my replacement eyes on RAH...
and in the RV-3, if you don't mind sitting on my lap.

Thank you, Russell.
Good job. <g>


Barnyard BOb --

[Russell Kent]

"Rich S." wrote:

> But I think "contains" is much more appropriate than "holds". Example - In
> front of you are two empty sacks; one of 150 lbs capacity (assuming standard
> crap mass/weight/volume/specific gravity) and another of 100 lbs capacity.
> Which one "holds" more? Which one contains more? There's no correct answer -
> it's just my opinion and probably stinks.

On this we vigorously agree: there's no correct answer. And I think, no, I'm
*certain* that was the point that nafod40 was attempting to make. My only point
of contention involved his particular sequence of numbers.

> Aviation reply - No wonder the N. Vietnamese hated the Bee 52!!! Would that
> be a weapon of Mass Corruption?

Actually, Dad said they carried and dropped "concrete blivets" out in some
bombing range out West. He also dropped real iron bombs over various parts of
S.E. Asia, but I never heard him say anything about dropping blivets, concrete
or otherwise, there. But you never know. There was some conversation about
ferrying the wing commander's Volkswagon (IIRC) in the bomb bay once during an
extended training deployment...

Russell Kent

[RobertR237]

In article >, RR Urban >
writes:

>
>
>>Bob Reed wrote:
>>
>>> Damn BOb, you sure are full of CRAP! ;-)))))
>>
>>I'm sure NO ONE here, not even the crotchety old fool himself, will deny
>that BOb
>>is full of crap (sometimes), *BUT* it was nafod40 whom you (Bob Reed) quoted
>and
>>not BOb.
>>
>>Russell Kent
>+++++++++++++++++++++++++++++++++++++++
>
>When I go blind from one too many Muzzleloaders....
>You can officially be my replacement eyes on RAH...
>and in the RV-3, if you don't mind sitting on my lap.
>
>Thank you, Russell.
>Good job. <g>
>
>
>Barnyard BOb --
>
>

What can I say, everything was browned out, the smell was overwhelming and I
screwed up! It's been one of those days, weeks, months, years, whatever, I
screwed up and you are not full of crap after all.


XLAX to the rescue!!!!!!




Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)

[Del Rawlins]

On 08 Dec 2003 03:14 PM, RobertR237 posted the following:

>>When I go blind from one too many Muzzleloaders....
>>You can officially be my replacement eyes on RAH...
>>and in the RV-3, if you don't mind sitting on my lap.
>>
>>Thank you, Russell.
>>Good job. <g>
>>
>>
>>Barnyard BOb --
>>
>>
>
> What can I say, everything was browned out, the smell was overwhelming
> and I screwed up! It's been one of those days, weeks, months, years,
> whatever, I screwed up and you are not full of crap after all.
>
>
> XLAX to the rescue!!!!!!

No need to go bringing that dumbass back to the newsgroup. Besides, I
think that BOb likes his RV spars just the way they are.

----------------------------------------------------
Del "old troll week" Rawlins

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

[ChuckSlusarczyk]

In article >, nafod40 says...

>To paraphrase the question...
>
>If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
>lb bag, which bag is holding more crap?
>

Depends...

Chuck S

[PW]

"Mark" > wrote in message
...
> Hi All, thanks for the responses, was not meant to be a trick question but
> definately a newbie question. I was curious after reading about people
using
> mazda 13b engines for various homebuilts, and porting them, adding on
> various components to boost the hp from 200 to 260+. Seems at a point that
> it's overkill if the 200 hp engine is going to provide you with the
needed
> ponies and rpms to accomplish the same as the 260 hp engine. What would
the
> advantge be of having the extra horsepower ?
>
> Thanks,
>
> Mark
>
>
> "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 ?
> >
> >
> >
>
Mark,

A "typical" 13b (non-turbocharged) for aircraft is closer to 180-200 Hp.
A turbo will get you to that 250 hp mark, if you need it. Without the right
prop, the power is not usable.


Phillip

[Ron Wanttaja]

On 8 Dec 2003 20:06:47 -0800, ChuckSlusarczyk
> wrote:

>In article >, nafod40 says...
>
>>To paraphrase the question...
>>
>>If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
>>lb bag, which bag is holding more crap?
>
>Depends...

How much crap does your Depends hold? :-)

Ron Wanttaja

[PW]

"Orval Fairbairn" > wrote in message
...
> In article >,
> "Eric Miller" > wrote:
>
> > "RobertR237" > wrote in message
> > ...
> > > PS: This is a simple answer to your question but many factors are
> > involved.
> > > The effort to increase a 200 hp engine to 260 hp may or may not be
worth
> > the
> > > effort and the 30% increase in hp wil not produce an equilivent
increase
> > in
> > > thrust or speed. I don't remember the formula for calculating the
> > increase but
> > > it is far less than anticipated.
> >
> > Speed increases at about the cube root of the HP increase, so:
> >
> > (260 / 200) ^ (1 / 3) = 1.091 or about 9% faster with 30% more HP
> >
> > But other factors to consider are the increased weight of a larger
engine,
> > the increased fuel burn, and the weight of that fuel.
> >
> > Eric
> >
> >
>
> Extra horsepower converts directly into rate of climb, assuming the same
> weight and airspeed. Fuel consumption rises approximately in proportion
> to horsepower; stability decreases.
>
> Other factors in boosting phenomenal horsepower out of small packages:
>
> Increased thermal load
> Increased stress on all parts of the engine
> Some high RPM ranges may not yield usable thrust because the prop tips
> are in the transonic range, where prop efficiency decreases greatly.

And in the case of a rotary, you WILL be spinning the engine around 6000 or
so RPM. This means you must also use a PSRU to drop the RPM down to
something usable for the prop. The nice thing is, 6000 shaft RPM is only
2000 rotor RPM. The 13b can handle 6-8 grand with no problems.

Phillip

[ChuckSlusarczyk]

In article >, Ron Wanttaja says...

>>>If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
>>>lb bag, which bag is holding more crap?
>>
>>Depends...
>
>How much crap does your Depends hold? :-)

Depends :-)

Chuck(where's the prunes ?) S

[nafod40]

Russell Kent wrote:
> nafod40 wrote:
>
>
>>RR Urban wrote:
>>
>>>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 ?
>>>
>>To paraphrase the question...
>>
>>If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
>>lb bag, which bag is holding more crap?
>
>
> OOooooooo..... *SO* close, and yet just off. I think you meant to say:
> "If I put 100 lbs of crap in a 100 lb bag, and 100 lbs of crap in a 150 lb bag,
> which bag holds more crap?"

My language was carefully chosen with the utmost attention to detail. To
paraphrase Humpty-Dumpty...

"When I use a phrase," Humpty Dumpty said, in rather a scornful tone,
"it means just what I choose it to mean—neither more nor less."

"The question is, " said Alice, "whether you can make words mean so many
different things."

"The question is," said Humpty Dumpty. "which is to be master—that's all."

[nafod40]

Ron Wanttaja wrote:
> ChuckSlusarczyk wrote:
>
>
>>In article >, nafod40 says...
>>
>>
>>>To paraphrase the question...
>>>
>>>If I put 150 lbs of crap in a 100 lb bag, and 150 lbs of crap in a 150
>>>lb bag, which bag is holding more crap?
>>
>>Depends...
>
>
> How much crap does your Depends hold? :-)

Ba-dummm-bump <-cymbal->