Today's Message Index:
----------------------
1. 03:53 AM - Re: Power (Kevin Kimball)
2. 04:48 AM - Re: How old is too old? (A. Dennis Savarese)
3. 05:35 AM - Re: Power (Richard Goode)
4. 07:59 AM - Re: Power (Fly4fude)
5. 08:49 AM - Re: Power (psb777)
6. 09:44 AM - Re: Re: Power (Roger Kemp M.D.)
7. 09:49 AM - Re: Re: Power (Roger Kemp M.D.)
8. 01:50 PM - Re: Re: Power (Kevin Kimball)
9. 02:06 PM - Re: Power (psb777)
10. 03:58 PM - Re: How old is too old? (keithmckinley)
11. 03:58 PM - Re: How old is too old? (keithmckinley)
12. 07:53 PM - Re: Power (N642K)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Jim,
The short answer to your question is no. A 10% increase in thrust does
not directly pair with the same % increase in horsepower. Thrust is a
product of torque and it is possible to increase torque without
increasing hp the same % as seen in auto engines. A dyno measures
torque not horsepower. The hp numbers are derived from the torque
readings and then corrected for the conditions at the moment of the
run to a standard day.
Hp claims should be viewed as advertising and given just such value.
For example, there are engine builders who claim 400+ hp from 540
lycomings when in fact, when tested show less hp than engines claiming
330hp.
So far with BPE m14p engines, we see about 300# increase in thrust
compared to the stock engines. We have a pull test rig here to use for
this. This is about 18% increase in thrust from stock while at the
same time getting a decrease in head and oil temps, decrease in fuel
burn at cruise etc.
Sent from my iPhone
Kevin
On Apr 25, 2010, at 1:34 AM, cjpilot710@aol.com wrote:
>
>
> With a test cell, will be a great asset, practically if it has
> something that can accurately measure power.
>
> Here is a question. I do not have the answer to this and I'm sure I
> may be simplifying this big time.
>
> What if we took (say ) a CJ-6 with a straight M-14p (dymo tested at
> 360hp) engine and paddle prop.
> We (figuratively) tie it to a tree. Than we run the engine full
> power and full rpm.
> In the tie down line we have a gage that can measure the pull in
> pounds and that pull measured (say) 1,000 lbs.
> We than tear down the engine and insert dome pistons.
> We than put the engine back on the same airplane and again make a
> full power run.
> This time the gage in the line reads 1,110 pounds in pull. An
> increase of 110 lbs pull.
> If we have 1110/1000, I believe we have a 11.1% increase.
> If original engine equaled 360hp, would the new configuration equal
> 399.96 hp (360+11.1%)?
>
> BTW I was never known as being particularly astute in math.
>
> Jim "Pappy" Goolsby
>
>
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: How old is too old? |
I guess the question is, have you ever seen an airplane fresh from the
factory with wrinkles in the fuselage skins? I've always believed they
don't build them with wrinkles in the skins. Even the home builts like
the RV's don't have wrinkles or ripples in the fuselage skins. Doug may
be able to shed some light on the subject.
Dennis
----- Original Message -----
From: Pete Fowler
To: yak-list@matronics.com
Sent: Saturday, April 24, 2010 3:42 PM
Subject: Yak-List: How old is too old?
While working on my plane at Santa Paula, one of the many A&Ps there
happened by and was looking at my fuselage and said "wow, that plane
must have been overstressed at some point". We sort of ignored that but
since then I've noticed that my fuselage skins are more "wrinkly" from
behind the back seat to the tail. Compared to the "Fresh Off Boat" one I
saw today, that one had nearly perfectly smooth fuselage skins.
My plane is one of the first CJ-6s imported into the U.S. in 1991 and
had an estimated 3500 hours when imported so now has something like 4900
hours on the airframe. I know that's nothing compared to most other
planes but since it appears to be the (or one of the) highest hour
planes around, it made me think.
Am I the "guinea pig" for Nanchang hours? How would I determine if the
wrinkly skins are "normal"? The local Nanchang guys don't think anything
of it but what do you guys think?
--------
N4183E
http://nanchangcjs.yuku.com/
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295571#295571
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
A 10% increase in thrust is a good indicator of 10% more power ,but no
more than that.
Firstly,a prop will work more or less efficiently at certain powers-for
example the V-530 props on Yaks has a problem to transmit more than 350
HP.
Seccondly temp.and air pressure are likely to change,and finally,a
spring-type of gauge is not very accurate.
I go back to my original tennant,and that is,if someone makes any claim
about power,or performance [or whatever] it should have been properly
measured!
Richard
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Hereford
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
----- Original Message -----
From: cjpilot710@aol.com
To: yak-list@matronics.com
Sent: Sunday, April 25, 2010 6:34 AM
Subject: Yak-List: Power
With a test cell, will be a great asset, practically if it has
something that can accurately measure power.
Here is a question. I do not have the answer to this and I'm sure I
may be simplifying this big time.
What if we took (say ) a CJ-6 with a straight M-14p (dymo tested at
360hp) engine and paddle prop.
We (figuratively) tie it to a tree. Than we run the engine full power
and full rpm.
In the tie down line we have a gage that can measure the pull in
pounds and that pull measured (say) 1,000 lbs.
We than tear down the engine and insert dome pistons.
We than put the engine back on the same airplane and again make a full
power run.
This time the gage in the line reads 1,110 pounds in pull. An
increase of 110 lbs pull.
If we have 1110/1000, I believe we have a 11.1% increase.
If original engine equaled 360hp, would the new configuration equal
399.96 hp (360+11.1%)?
BTW I was never known as being particularly astute in math.
Jim "Pappy" Goolsby
--------------------------------------------------
This message has been scanned for viruses and
dangerous content by the Invictawiz MailScanner
and is believed to be clean.
http://www.invictawiz.com/
--------------------------------------------------
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Hi all!
I think you all might be making this way too complicated. Bill Blackwell is working
on my CJ right now. He assures me you can EASILY get ten (10) EXTRA HORSEPOWER
simply by chroming the tail's skid-plate! [Laughing]
--------
Scott "Gabby" Wallace
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295632#295632
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
I'm frustrated by repeated attempts here by some to use
the terms torque, power and thrust as if they're
interchangeable terms, but I'll leave that alone, for the time
being at least.
Who needs any equipment to measure a power difference?
There is a much easier, cheaper, better and much more
reliable way of measuring the change in the power produced
by an aircraft engine. It doesn't tell you the absolute
level of power produced - but it does tell you very
accurately the difference in power caused by any
engine mod.
Accurately measure the rate of climb at a
nominated set speed in the aircraft before the mod.
Don't use the VSI - there is no reason for these
to be calibrated correctly - use the altimeter and
a stopwatch.
Then do the engine mod and repeat the experiment.
We want to keep drag the same so fly the modded a/c
at the same speed as before. Assure the a/c has
the same weight. Any power difference then goes
entirely into providing a different rate of climb.
The formula for the power difference is,
Pd = m * g * (v2 - v1)
where
g is acceleration due to gravity,
m is the aircraft mass in kg,
v1 and v2 are the original and new climb rate in m/s,
Pd is the power difference caused by the mod in Watts.
Knowing
g = 9.81 m/s/s
1 Horsepower is 747 W.
1 m/s = 197 ft/min
1 kg = 2.20 lb
then, in old units,
m is now the aircraft mass in lb,
v1 and v2 are the original and new climb rate but now in feet/min, and
Pd is the power difference caused by the mod but now in hp.
Pd*747 = m/2.2 * 9.81 * (v2 - v1)/197
or, simplifying,
Pd = m * (v2 - v1) / 33100
E.g.
An M14P mod is claimed to increase power from 360
to 440hp. Before the mod I climb my 3000lb Yak-18T
at 1200ft/min full throttle max-RPM at an exact set
speed. After the mod, same atmospheric conditions,
*same* speed I can climb at 1400ft/min all levers
forward.
The power increase is
3000 * (1400 - 1200) / 33100 = 18 hp
--------
Paul Beardsell
HA-YAB http://beardsell.com/flying/ha-yab
Yak-18T http://beardsell.com/flying/yak18t
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295635#295635
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Yes and also by using the 18th century medical device known as the medicinal
smoke bellows for rectal lavage...aka blowing smoke up ones ass.
Doc
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Fly4fude
Sent: Sunday, April 25, 2010 9:58 AM
Subject: Yak-List: Re: Power
Hi all!
I think you all might be making this way too complicated. Bill Blackwell is
working on my CJ right now. He assures me you can EASILY get ten (10) EXTRA
HORSEPOWER simply by chroming the tail's skid-plate! [Laughing]
--------
Scott "Gabby" Wallace
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295632#295632
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
I knew an aeronautical engineer would climb out of the lurking woodwork
eventually. Where have you been so long?
Thanks for the info.
Doc
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of psb777
Sent: Sunday, April 25, 2010 10:48 AM
Subject: Yak-List: Re: Power
I'm frustrated by repeated attempts here by some to use
the terms torque, power and thrust as if they're
interchangeable terms, but I'll leave that alone, for the time
being at least.
Who needs any equipment to measure a power difference?
There is a much easier, cheaper, better and much more
reliable way of measuring the change in the power produced
by an aircraft engine. It doesn't tell you the absolute
level of power produced - but it does tell you very
accurately the difference in power caused by any
engine mod.
Accurately measure the rate of climb at a
nominated set speed in the aircraft before the mod.
Don't use the VSI - there is no reason for these
to be calibrated correctly - use the altimeter and
a stopwatch.
Then do the engine mod and repeat the experiment.
We want to keep drag the same so fly the modded a/c
at the same speed as before. Assure the a/c has
the same weight. Any power difference then goes
entirely into providing a different rate of climb.
The formula for the power difference is,
Pd = m * g * (v2 - v1)
where
g is acceleration due to gravity,
m is the aircraft mass in kg,
v1 and v2 are the original and new climb rate in m/s,
Pd is the power difference caused by the mod in Watts.
Knowing
g = 9.81 m/s/s
1 Horsepower is 747 W.
1 m/s = 197 ft/min
1 kg = 2.20 lb
then, in old units,
m is now the aircraft mass in lb,
v1 and v2 are the original and new climb rate but now in feet/min, and
Pd is the power difference caused by the mod but now in hp.
Pd*747 = m/2.2 * 9.81 * (v2 - v1)/197
or, simplifying,
Pd = m * (v2 - v1) / 33100
E.g.
An M14P mod is claimed to increase power from 360
to 440hp. Before the mod I climb my 3000lb Yak-18T
at 1200ft/min full throttle max-RPM at an exact set
speed. After the mod, same atmospheric conditions,
*same* speed I can climb at 1400ft/min all levers
forward.
The power increase is
3000 * (1400 - 1200) / 33100 = 18 hp
--------
Paul Beardsell
HA-YAB http://beardsell.com/flying/ha-yab
Yak-18T http://beardsell.com/flying/yak18t
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295635#295635
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Paul,
Cool. So if i understand your example, your aiplane would
Need to see 400 fpm increase in roc to 1600 fpm to realize a 10%
increase in hp.
Likewise, to go from 360 hp to 440 hp as in your example, your
airplane would need to see a roc increase of 882 fpm to 2082fpm.
That's huge at 73% increase in roc with a 22% increase in hp.
Hope my math is ok here Maybe I missed something on these calcs as I
am walking through lowes after a day on the lakes.
Sent from my iPhone
Kevin
On Apr 25, 2010, at 11:48 AM, "psb777" <matronics.com@beardsell.com>
wrote:
>
> I'm frustrated by repeated attempts here by some to use
> the terms torque, power and thrust as if they're
> interchangeable terms, but I'll leave that alone, for the time
> being at least.
>
> Who needs any equipment to measure a power difference?
> There is a much easier, cheaper, better and much more
> reliable way of measuring the change in the power produced
> by an aircraft engine. It doesn't tell you the absolute
> level of power produced - but it does tell you very
> accurately the difference in power caused by any
> engine mod.
>
> Accurately measure the rate of climb at a
> nominated set speed in the aircraft before the mod.
> Don't use the VSI - there is no reason for these
> to be calibrated correctly - use the altimeter and
> a stopwatch.
>
> Then do the engine mod and repeat the experiment.
> We want to keep drag the same so fly the modded a/c
> at the same speed as before. Assure the a/c has
> the same weight. Any power difference then goes
> entirely into providing a different rate of climb.
> The formula for the power difference is,
>
> Pd = m * g * (v2 - v1)
>
> where
> g is acceleration due to gravity,
> m is the aircraft mass in kg,
> v1 and v2 are the original and new climb rate in m/s,
> Pd is the power difference caused by the mod in Watts.
>
> Knowing
> g = 9.81 m/s/s
> 1 Horsepower is 747 W.
> 1 m/s = 197 ft/min
> 1 kg = 2.20 lb
>
> then, in old units,
> m is now the aircraft mass in lb,
> v1 and v2 are the original and new climb rate but now in feet/min, and
> Pd is the power difference caused by the mod but now in hp.
>
> Pd*747 = m/2.2 * 9.81 * (v2 - v1)/197
> or, simplifying,
> Pd = m * (v2 - v1) / 33100
>
> E.g.
>
> An M14P mod is claimed to increase power from 360
> to 440hp. Before the mod I climb my 3000lb Yak-18T
> at 1200ft/min full throttle max-RPM at an exact set
> speed. After the mod, same atmospheric conditions,
> *same* speed I can climb at 1400ft/min all levers
> forward.
>
> The power increase is
> 3000 * (1400 - 1200) / 33100 = 18 hp
>
> --------
> Paul Beardsell
> HA-YAB http://beardsell.com/flying/ha-yab
> Yak-18T http://beardsell.com/flying/yak18t
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=295635#295635
>
>
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
All correct except of course my 18T is rarely lighter than 3300 lb or 10% more
than I said so its another 10% i.e. not 18hp but 20hp for an extra 200fpm
That's the point of course: For any 3300lb plane, with any engine, another 10hp
is needed to add another 100fpm to the climb.
kjkimball(at)AOL.COM wrote:
> Paul,
>
> Cool. So if i understand your example, your aiplane would
> Need to see 400 fpm increase in roc to 1600 fpm to realize a 10%
> increase in hp.
>
> Likewise, to go from 360 hp to 440 hp as in your example, your
> airplane would need to see a roc increase of 882 fpm to 2082fpm.
> That's huge at 73% increase in roc with a 22% increase in hp.
>
> Hope my math is ok here Maybe I missed something on these calcs as I
> am walking through lowes after a day on the lakes.
>
> Sent from my iPhone
> Kevin
>
--------
Paul Beardsell
HA-YAB http://beardsell.com/flying/ha-yab
Yak-18T http://beardsell.com/flying/yak18t
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295667#295667
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: How old is too old? |
how about posting some pictures?
--------
Keith McKinley
700HS
KFIT
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295684#295684
Message 11
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: How old is too old? |
how about posting some pictures?
--------
Keith McKinley
700HS
KFIT
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295685#295685
Message 12
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
My two rules:
1. Money spent on the airplane always makes them faster and sexier.
2. Never do math in public.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=295710#295710
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|