Today's Message Index:
----------------------
1. 11:06 AM - Adv. CLECOS On Sale at Brown Tool (browntool@AOL.COM)
2. 11:31 AM - Pitot testing (Ralph E. Capen)
3. 11:39 AM - Should I re-pitch my prop? (Knicholas2@aol.com)
4. 12:08 PM - Re: Should I re-pitch my prop? (Michael W Stewart)
5. 12:20 PM - Re: Should I re-pitch my prop? (David Leonard)
6. 01:56 PM - Re: Should I re-pitch my prop? (Jack Hilditch)
7. 02:12 PM - Re: Should I re-pitch my prop? (linn Walters)
8. 03:17 PM - Re: Pitot testing (Kevin Horton)
9. 05:41 PM - Re: Should I re-pitch my prop? (Sam Buchanan)
Message 1
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| Subject: | Adv. CLECOS On Sale at Brown Tool |
Hi All,
Just a quick post to let you know that our special sale for the Van's Air Force Family is now going and we are offering several items at special VAF only sale pricing. You can see the complete special sale flyer on the front of the VAF website at www.vansairforce.net
* We are offering Clecos in bags of 100 at our 1000 piece price - $37.00 per bag
of 100!?
* Made in the USA Microstop Countersink Cage for only $21.95 (NOT a cheap Chinese
import!)
* Made in the USA 2 Piece Chip Chaser Set for only $6.95
* Made in the USA 135 Degree Split Point Drill Sets with Metal Index Box - choose
Cobalt or HSS - both on sale.
* Made in the USA Sioux Mini Palm Drill, Model 1412, 3600 rpm, on sale for $204.95!
These special prices are NOT available to the general public, and you MUST mention
this special offer when ordering now thru December 23rd.
Notice that we have made a conscious decision to offer only AMERICAN MADE products
in this special offer. Not only can you save some money, but you can also
help an American factory worker keep his or her job. With the flood of Chinese
and Taiwanese imports entering the aircraft tool industry, many of the smaller
mom & pop factories that make?specialty aircraft tools are struggling.
Thanks to all and on behalf of everyone at Brown Tool, we wish every one a very
Merry Christmas!? (or, the winter holiday of your choice if Christmas is not
your thing!)
Michael Brown
Brown Aviation Tool Supply Co.
2536 S.E. 15th Street
Oklahoma City, OK 73129
405-688-6888
800-587-3883
michael@browntool.com
www.browntool.com
DO NOT ARCHIVE
Message 2
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Folks,
I have been doing my Pitot testing. I have built a manometer per the EAA chapter
1000 instructions and using the MicroEncoder chart and Kevin Horton's spreadsheet.
Here are some results:
At lower airspeed numbers, the manometer readings are exact. As the airspeed numbers
rise, the manometer readings deviate from the numbers on the spreadsheet
that I have (thanks Kevin Horton) to the low side - meaning the manometer reading
is lower than specified for a given airspeed indication...also meaning that
the airspeed would indicate an amount higher than actual for the correct manometer
reading. All are within the 3% or 5kts specified by FAR 23.1323.
Also, I am experiencing a very slow bleed-down - on the order of 4 to 7 minutes
to lose 100kts of airspeed at 0035'MSL. The only way I found this was walking
away to record my numbers in the computer after I was done - when I came back
it was lower.....did not see it between tests while I was doing it though.
I've looked through FAR 23.1323 - Airspeed indicating system. It does not have
anything in it regarding a leak tolerance...unlike the FAR 23.1325 - Static pressure
system, which allows 100fpm @ 1000' AGL indicated. What do folks use
for a leakdown tolerance? Or is this good enough to not matter?
Thanks,
Ralph Capen
Message 3
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| Subject: | Should I re-pitch my prop? |
My RV9 has the recommended fix pitch prop on my 150 HP Lycoming 0-320
engine. It has plenty of power and climb but I would like a little more speed
than
the current 135-140 kt cruise.
I am considering having the prop re-pitched for more speed.
What do others think? Good idea or bad? How much more should I have the
pitch increased?
Thanks in advance for input.
Kim Nicholas
RV9A
Auburn, WA
**************Life should be easier. So should your homepage. Try the NEW
AOL.com.
Message 4
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| Subject: | Re: Should I re-pitch my prop? |
we need more info.
current prop type, manufacturer size and pitch.
current WOT RPM at 8k'
Current cruise speed and RPM.
Current climb RPM, IAS and FPM altitude start
Mike
Knicholas2@aol.co
m
Sent by:
To
owner-rv-list-ser rv-list@matronics.com
ver@matronics.com
cc
Subj
ect
12/02/2008 02:38 RV-List: Should I re-pitch my pr
op?
PM
Please respond to
rv-list@matronics
.com
My RV9 has the recommended fix pitch prop on my 150 HP Lycoming 0-320
engine. It has plenty of power and climb but I would like a little mor
e
speed than the current 135-140 kt cruise.
I am considering having the prop re-pitched for more speed.
What do others think? Good idea or bad? How much more should I have t
he
pitch increased?
Thanks in advance for input.
Kim Nicholas
RV9A
Auburn, WA
Life should be ea&icid=aolcom40vanity&ncid=emlcntaolcom00000002">Tr
y the
NEW AOL.com.
========================
============
========================
============
========================
============
========================
============
Message 5
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| Subject: | Re: Should I re-pitch my prop? |
That all depends on what RPM you are showing in climb and cruise and how
much throttle you have available in cruise.
You are bounded by 2 extremes: the ultimate climb prop, and the ultimate
cruise prop.
The ultimate climb prop will achieve full rated engine RPM in climb (at full
throttle) but you will have to throttle back significantly in cruise to
avoid exceeding redline.
The ultimate cruise prop will achieve full rated engine RPM in level flight
and full throttle but your climbout will be at less than full RPM
(therefore, less than max power). You could actually go beyond cruise prop
and have a 'descent prop' where you can actually descend slightly at full
power and not exceed redline RPM. That will decrease your max cruise speed
somewhat (and really hurt climb rate) but at least full throttle cruise will
be at a more comfortable economy cruise RPM.
Where you fall in that range is a matter of personal preference. I actually
have 'descent prop' and really like it, but my turbo allows me to make up
for what would otherwise be poor climb performance.
For the specifics of how much pitch change will take you from one type of
prop to the next, you need to talk to the maker of the prop and your
re-pitching shop.
David Leonard
Turbo Rotary RV-6
On Tue, Dec 2, 2008 at 11:38 AM, <Knicholas2@aol.com> wrote:
>
>
> My RV9 has the recommended fix pitch prop on my 150 HP Lycoming 0-320
> engine. It has plenty of power and climb but I would like a little more
> speed than the current 135-140 kt cruise.
>
> I am considering having the prop re-pitched for more speed.
> What do others think? Good idea or bad? How much more should I have the
> pitch increased?
>
> Thanks in advance for input.
>
> Kim Nicholas
> RV9A
> Auburn, WA
>
>
> ------------------------------
> Life should be ea&icid=aolcom40vanity&ncid=emlcntaolcom00000002">Try the
> NEW AOL.com.
>
> *
>
>
-
Message 6
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| Subject: | Should I re-pitch my prop? |
If memory serves me right, didn't Van's recommend against re-pitching metal
props taken from spam-cans? I poked around a bit and found the following on
Van's site.
"The Sensenich metal propellers we sell were developed specifically for the RV
series and are the ONLY fixed pitch metal propellers approved by Van's Aircraft
Inc. for use on RV aircraft. "
"Propellers from production aircraft are not suitable, and unfortunate
experience has shown that modified production propellers can fail without
warning with deadly consequences."
Full article can be found at:
http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1228254533-26-123
<http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1228254533-26-123&browse
props&product=sen-prop> &browse=props&product=sen-prop
Jack Hilditch
RV-9A ( R ) project
Manchester, CT
_____
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of David Leonard
Sent: Tuesday, December 02, 2008 3:20 PM
Subject: Re: RV-List: Should I re-pitch my prop?
That all depends on what RPM you are showing in climb and cruise and how much
throttle you have available in cruise.
You are bounded by 2 extremes: the ultimate climb prop, and the ultimate cruise
prop.
The ultimate climb prop will achieve full rated engine RPM in climb (at full
throttle) but you will have to throttle back significantly in cruise to avoid
exceeding redline.
The ultimate cruise prop will achieve full rated engine RPM in level flight and
full throttle but your climbout will be at less than full RPM (therefore, less
than max power). You could actually go beyond cruise prop and have a 'descent
prop' where you can actually descend slightly at full power and not exceed
redline RPM. That will decrease your max cruise speed somewhat (and really hurt
climb rate) but at least full throttle cruise will be at a more comfortable
economy cruise RPM.
Where you fall in that range is a matter of personal preference. I actually
have 'descent prop' and really like it, but my turbo allows me to make up for
what would otherwise be poor climb performance.
For the specifics of how much pitch change will take you from one type of prop
to the next, you need to talk to the maker of the prop and your re-pitching
shop.
David Leonard
Turbo Rotary RV-6
On Tue, Dec 2, 2008 at 11:38 AM, <Knicholas2@aol.com> wrote:
My RV9 has the recommended fix pitch prop on my 150 HP Lycoming 0-320 engine.
It has plenty of power and climb but I would like a little more speed than the
current 135-140 kt cruise.
I am considering having the prop re-pitched for more speed.
What do others think? Good idea or bad? How much more should I have the pitch
increased?
Thanks in advance for input.
Kim Nicholas
RV9A
Auburn, WA
_____
Life should be ea&icid=aolcom40vanity&ncid=emlcntaolcom00000002">Try the NEW
AOL.com.
-
Message 7
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| Subject: | Re: Should I re-pitch my prop? |
From a practical standpoint there shouldn't be any reason why a 'spam
can' prop from the same engine won't work on Van's airplanes. What he
says about failures is true and should be part of your decision on where
your prop comes from. A prop can only be pitched and re-pitched so many
inches total, and then it's junk. When a prop is repitched, the change
is stamped on the hub. Or at least it should be. I think this is the
root of Van's warning. Documentation can be lacking so be careful.
Without an accurate prop log, which wasn't 'required' when I began my
road to the poorhouse, you can't be sure of the hours it has on it,
whether it was straightened after a slight prop strike or not ..... see
where I'm going on this???
Van likes Sensenich props, and that's the only ones he's 'tested' on his
birds .... hence the word 'approved' in his warning. A McCauley may be
better or worse than the Sensenich .... only testing would tell.
Linn
Jack Hilditch wrote:
>
> If memory serves me right, didnt Vans recommend against re-pitching
> metal props taken from spam-cans? I poked around a bit and found the
> following on Vans site.
>
> The Sensenich metal propellers we sell were developed specifically
> for the RV series and are the ONLY fixed pitch metal propellers
> approved by Van's Aircraft Inc. for use on RV aircraft.
>
> Propellers from production aircraft are not suitable, and unfortunate
> experience has shown that modified production propellers can fail
> without warning with deadly consequences.
>
> Full article can be found at:
>
> http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1228254533-26-123&browse=props&product=sen-prop
> <http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1228254533-26-123&browse=props&product=sen-prop>
>
> Jack Hilditch
>
> RV-9A ( R ) project
>
> Manchester, CT
>
> ------------------------------------------------------------------------
>
> **
>
Message 8
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| Subject: | Re: Pitot testing |
On 2-Dec-08, at 14:29 , Ralph E. Capen wrote:
> <recapen@earthlink.net>
>
> I have been doing my Pitot testing. I have built a manometer per
> the EAA chapter 1000 instructions and using the MicroEncoder chart
> and Kevin Horton's spreadsheet.
>
> Here are some results:
>
> At lower airspeed numbers, the manometer readings are exact. As the
> airspeed numbers rise, the manometer readings deviate from the
> numbers on the spreadsheet that I have (thanks Kevin Horton) to the
> low side - meaning the manometer reading is lower than specified for
> a given airspeed indication...also meaning that the airspeed would
> indicate an amount higher than actual for the correct manometer
> reading. All are within the 3% or 5kts specified by FAR 23.1323.
>
> Also, I am experiencing a very slow bleed-down - on the order of 4
> to 7 minutes to lose 100kts of airspeed at 0035'MSL. The only way I
> found this was walking away to record my numbers in the computer
> after I was done - when I came back it was lower.....did not see it
> between tests while I was doing it though.
>
> I've looked through FAR 23.1323 - Airspeed indicating system. It
> does not have anything in it regarding a leak tolerance...unlike the
> FAR 23.1325 - Static pressure system, which allows 100fpm @ 1000'
> AGL indicated. What do folks use for a leakdown tolerance? Or is
> this good enough to not matter?
If a pitot system has no leaks, there is no air moving in it if you
are at a constant airspeed. The pressure will be the same everywhere
in the pitot system - i.e. the pressure at the entrance to the ASI
will be the same as the pressure at the pitot tube. If there is a
leak in the system, air must continually flow from the pitot tube to
the leak to replenish the air lost through the leak. Air will only
flow if there is a pressure differential to push it, so the pressure
at the leak has to be lower than the pressure at the pitot tube. But,
if the leak is small, the speed at which the air will be flowing will
be small, and the pressure differential required to push the air at
that rate will be small. Thus the effect of a very small leak is
negligible. The closer a leak is to the pitot entrance, the less
significant it is, as the pressure loss is proportional to the length
of tube that has air flowing it it. No air is flowing in the part of
the system between the leak and the ASI, so no further pressure loss
is occurring there.
A leak becomes a problem if it is big enough so there is an
appreciable pressure loss required to push the air through the system
from the pitot tube to the leak.
Your leak is very small, so it probably isn't causing an accuracy
problem now. But, it is a sign of a flaw in your system somewhere,
and I would wonder whether it will further degrade such that someday
it becomes a problem. If you don't find and fix it, I would do some
sort of periodic check to ensure that it hasn't gotten worse.
--
Kevin Horton RV-8 (Grounded)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 9
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| Subject: | Re: Should I re-pitch my prop? |
linn Walters wrote:
>
> From a practical standpoint there shouldn't be any reason why a 'spam
> can' prop from the same engine won't work on Van's airplanes.
<snip>
The reason very few fixed-pitch "spam can props" are practical for an RV
is because the speedy RV needs far more pitch than a C172 or similar
aircraft. The RV Sensenich props are steeply pitched, so much so that
special templates are required for a prop shop to measure the pitch. The
"big lever" method of repitching an RV prop is very difficult due to the
thick blade root. A return to Sensenich for repitch on their hydraulic
rig is the best way to go for our props.
The gory details of the repitching of my Sensenich by a local prop shop:
http://thervjournal.com/fairings.htm#repitch
Sam Buchanan
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