Today's Message Index:
----------------------
0. 12:25 AM - Just Two Days Left... (Matt Dralle)
1. 06:40 AM - Re: Throttle setting at higher cruising altitudes (Mozam)
2. 11:27 AM - Freon & on & on & on (Jon Boede)
3. 11:52 AM - Re: Freon & on & on & on (Cliff Coy)
4. 02:24 PM - Re: Throttle setting at higher cruising altitudes (napeone)
5. 02:25 PM - Re: Re: Throttle setting at higher cruising altitudes (Mark Davis)
6. 02:47 PM - Re: Re: Throttle setting at higher cruising altitudes (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
7. 03:23 PM - Re: Re: Throttle setting at higher cruising altitudes (Mark Davis)
8. 03:24 PM - Re: Re: Throttle setting at higher cruising altitudes (Walter Lannon)
9. 03:51 PM - Re: Re: Throttle setting at higher cruising altitudes (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
10. 04:12 PM - Re: Re: Throttle setting at higher cruising altitudes (Brian Lloyd)
11. 04:28 PM - Re: Throttle setting at higher cruising altitudes (Mozam)
12. 04:34 PM - Re: Throttle setting at higher cruising altitudes (Mozam)
13. 04:37 PM - Thermodynamic efficiency (was: Re: Throttle setting at higher cruising altitudes) (Brian Lloyd)
14. 04:40 PM - M14 P TBO (B747crew)
15. 04:47 PM - Re: Re: Throttle setting at higher cruising altitudes (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
16. 04:48 PM - Re: Re: Throttle setting at higher cruising altitudes (Brian Lloyd)
17. 04:54 PM - Re: Freon & on & on & on (Brian Lloyd)
18. 04:54 PM - Re: Freon & on & on & on (Brian Lloyd)
19. 05:03 PM - Re: Re: Throttle setting at higher cruising altitudes (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
20. 05:04 PM - Re: Freon & on & on & on (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
21. 05:23 PM - Re: Freon & on & on & on (Brian Lloyd)
22. 05:33 PM - Re: Re: Throttle setting at higher cruising altitudes (Walter Lannon)
23. 05:54 PM - Re: M14 P TBO (Cliff Coy)
24. 06:07 PM - Re: Freon & on & on & on (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
25. 06:58 PM - Re: Re: Throttle setting at higher cruising altitudes (N13472@aol.com)
26. 07:18 PM - Re: Re: Throttle setting at higher cruising altitudes (Walter Lannon)
27. 07:21 PM - Skycatcher to be made in China (Craig Winkelmann, CFI)
28. 07:23 PM - Re: M14 P TBO (Roger Kemp)
29. 07:38 PM - Re: Re: Throttle setting at higher cruising altitudes (Roger Kemp)
30. 07:55 PM - Re: Re: Throttle setting at higher cruising altitudes (Mark Davis)
31. 08:50 PM - Re: Re: Throttle setting at higher cruising altitudes (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
32. 09:07 PM - Re: Re: Throttle setting at higher cruising altitudes (Roger Kemp)
33. 09:10 PM - Re: Freon & on & on & on (Jon Boede)
34. 09:12 PM - Re: Re: Throttle setting at higher cruising altitudes (viperdoc)
35. 09:44 PM - Re: Re: Throttle setting at higher cruising altitudes (Brian Lloyd)
36. 09:46 PM - Re: Re: Throttle setting at higher cruising altitudes (Brian Lloyd)
Message 0
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| Subject: | Just Two Days Left... |
Dear Listers,
There are just a couple days left for this year's List Fund Raiser. Over all,
participation has been good, but things have been pretty slow this week for some
reason. If you've been putting off making your Contribution until the last
minute, this is it! The last minute, that is... :-)
Please remember that there isn't any sort of commercial advertising on the Lists
and the *only* means of keeping these Lists running is through your Contributions
during this Fund Raiser.
Please make a Contribution today!
http://www.matronics.com/contribution
Thank you!
Matt Dralle
Matronics Email List Administrator
Message 1
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| Subject: | Re: Throttle setting at higher cruising altitudes |
I have a Fuel Scan unit in my TW that has proved to be very accurate.
During high altitude cruise (say above 6,000'), I cannot detect any evidence of
this full throttle enrichment.
For example, at 9,500' with the prop at 65%, I can place the throttle at the forward
stop, note the fuel flow, then retard the throttle until the manifold pressure
drops several inches (this is a couple inches of throttle movement), and
I see very little change in fuel flow.
It appears to me that if there is any full throttle fuel enrichment, it is "disengaged"
at "higher" altitudes.
Also, FWIW, I have found that RPM has a much greater effect on fuel flow than manifold
pressure (throttle position). In other words, pulling the prop back from
70% to 65% reduces the fuel flow more than leaving the prop at 70% and reducing
the manifold pressure three or four inches.
So at high altitude with a nice tailwind I pull the prop back to 60% and put the
throttle at the forward stop. This results in a fuel flow of about 12.8 gal/hr.
Just my opinion (based on my Fuel Scan observations), I think the most fuel efficient
M-14 throttle setting for cruise is to set the throttle at the boost limit
for any given RPM setting.
Note: Your mileage may vary, past returns are no guarantee of future returns,
some assembly required, batteries not included, etc.
Cheers,
Steve Dalton
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=149343#149343
Message 2
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| Subject: | Freon & on & on & on |
So, before I do something stoopid (again)...
I got a nice Freon leak detector on eBay for $50... detects all things halo
genated at leak rates as low as 3gm/year.
And practically everything in the museum has some kind of pneumatic system
on it -- from the CJ up through the MI-24 to the MiG-23. So getting "good"
at finding leaks would have plenty of application.
I am under the delusion that putting a shot of Freon into said system and s
niffing with the leak detector is a good way to find all the leaks.
But, being the non-chemist that I am, I thought I'd ask around first before
I do something ignorant. :-)
I read through the list of refrigerants and it looks like R-23 (trifluorome
thane / Fluoroform) or R-503 (R-13/R-23 mix) has a sufficiently high vapor
pressure (about 4.4 MPa) at room temperature that I can pump some of the Fr
eon into an empty nitrogen pony bottle, bump it up with nitrogen and then r
un the whole system up to a pretty good pressure without the Freon turning
into a liquid.
Anybody have any objections to all this? Is running CFCs or HFCs into alum
inum tubing a bad idea?
In some systems (e.g. L-39) the nitrogen system also supplies head pressure
to the hydraulic system. Is mixing CFCs/HFCs and MIL-5606 a bad idea?
Suggestions?
Thanks,Jon
Message 3
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| Subject: | Re: Freon & on & on & on |
Most leak detectors do not react with the freon (a very inert gas), but
actually detect the ultrasonic sound the leak makes.
Cheers,
Cliff
Jon Boede wrote:
> So, before I do something stoopid (again)...
>
> I got a nice Freon leak detector on eBay for $50... detects all things
> halogenated at leak rates as low as 3gm/year.
>
> And practically everything in the museum has some kind of pneumatic
> system on it -- from the CJ up through the MI-24 to the MiG-23. So
> getting "good" at finding leaks would have plenty of application.
>
> I am under the delusion that putting a shot of Freon into said system
> and sniffing with the leak detector is a good way to find all the leaks.
>
> But, being the non-chemist that I am, I thought I'd ask around first
> before I do something ignorant. :-)
>
> I read through the list of refrigerants and it looks like R-23
> (trifluoromethane / Fluoroform) or R-503 (R-13/R-23 mix) has a
> sufficiently high vapor pressure (about 4.4 MPa) at room temperature
> that I can pump some of the Freon into an empty nitrogen pony bottle,
> bump it up with nitrogen and then run the whole system up to a pretty
> good pressure without the Freon turning into a liquid.
>
> Anybody have any objections to all this? Is running CFCs or HFCs into
> aluminum tubing a bad idea?
>
> In some systems (e.g. L-39) the nitrogen system also supplies head
> pressure to the hydraulic system. Is mixing CFCs/HFCs and MIL-5606 a
> bad idea?
>
> Suggestions?
>
> Thanks,
> Jon
>
> *
>
>
> *
--
Clifford Coy
Director of Maintenance
Border Air Ltd
629 Airport Rd.
Swanton, VT 05488
802-868-2822 TEL
802-868-4465 FAX
Skype: callto:Cliff.Coy <callto:cliff.coy>
Message 4
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Concur with Mozam.
David H.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=149433#149433
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Steve and Mark,
Thanks for the replies. I have noticed it appears to be a bit leaner
when running at 65% vs. 70%. So, I've been running at 70% into headwinds
and 65% with tailwinds.
Mark Davis
N44YK
----- Original Message -----
From: "Mozam" <sdalton@hughes.net>
Sent: Thursday, November 29, 2007 7:39 AM
Subject: Yak-List: Re: Throttle setting at higher cruising altitudes
>
> I have a Fuel Scan unit in my TW that has proved to be very accurate.
>
> During high altitude cruise (say above 6,000'), I cannot detect any
> evidence of this full throttle enrichment.
>
> For example, at 9,500' with the prop at 65%, I can place the throttle at
> the forward stop, note the fuel flow, then retard the throttle until the
> manifold pressure drops several inches (this is a couple inches of
> throttle movement), and I see very little change in fuel flow.
>
> It appears to me that if there is any full throttle fuel enrichment, it is
> "disengaged" at "higher" altitudes.
>
> Also, FWIW, I have found that RPM has a much greater effect on fuel flow
> than manifold pressure (throttle position). In other words, pulling the
> prop back from 70% to 65% reduces the fuel flow more than leaving the prop
> at 70% and reducing the manifold pressure three or four inches.
>
> So at high altitude with a nice tailwind I pull the prop back to 60% and
> put the throttle at the forward stop. This results in a fuel flow of
> about 12.8 gal/hr.
>
> Just my opinion (based on my Fuel Scan observations), I think the most
> fuel efficient M-14 throttle setting for cruise is to set the throttle at
> the boost limit for any given RPM setting.
>
> Note: Your mileage may vary, past returns are no guarantee of future
> returns, some assembly required, batteries not included, etc.
>
> Cheers,
> Steve Dalton
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=149343#149343
>
>
>
Message 6
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| Subject: | Re: Throttle setting at higher cruising altitudes |
I did not have the instrumentation that Steve has when I came to the
belief that I stated, and I tend to defer to his testing. However, this
directly contradicts what Vladimir told me and I also trust HIS judgment
beyond others as well!
Makes me wonder if it might not be worthwhile to run the test again at
altitude but with higher RPM settings. I wonder if Steve's test would
duplicate at 10,000 feet and say 85% on the RPM? I would really like to
know the answer to this for sure in case I have somehow managed to
delude myself!
Steve did say: "I think the most fuel efficient M-14 throttle setting
for cruise is to set the throttle at the boost limit for any given RPM
setting.
To the best of my knowledge Steve, there are no "boost limits" to this
engine at ANY RPM.
Mark Bitterlich
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Mark Davis
Sent: Thursday, November 29, 2007 17:25
Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
Steve and Mark,
Thanks for the replies. I have noticed it appears to be a bit
leaner when running at 65% vs. 70%. So, I've been running at 70% into
headwinds and 65% with tailwinds.
Mark Davis
N44YK
----- Original Message -----
From: "Mozam" <sdalton@hughes.net>
Sent: Thursday, November 29, 2007 7:39 AM
Subject: Yak-List: Re: Throttle setting at higher cruising altitudes
>
> I have a Fuel Scan unit in my TW that has proved to be very accurate.
>
> During high altitude cruise (say above 6,000'), I cannot detect any
> evidence of this full throttle enrichment.
>
> For example, at 9,500' with the prop at 65%, I can place the throttle
at
> the forward stop, note the fuel flow, then retard the throttle until
the
> manifold pressure drops several inches (this is a couple inches of
> throttle movement), and I see very little change in fuel flow.
>
> It appears to me that if there is any full throttle fuel enrichment,
it is
> "disengaged" at "higher" altitudes.
>
> Also, FWIW, I have found that RPM has a much greater effect on fuel
flow
> than manifold pressure (throttle position). In other words, pulling
the
> prop back from 70% to 65% reduces the fuel flow more than leaving the
prop
> at 70% and reducing the manifold pressure three or four inches.
>
> So at high altitude with a nice tailwind I pull the prop back to 60%
and
> put the throttle at the forward stop. This results in a fuel flow of
> about 12.8 gal/hr.
>
> Just my opinion (based on my Fuel Scan observations), I think the most
> fuel efficient M-14 throttle setting for cruise is to set the throttle
at
> the boost limit for any given RPM setting.
>
> Note: Your mileage may vary, past returns are no guarantee of future
> returns, some assembly required, batteries not included, etc.
>
> Cheers,
> Steve Dalton
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=149343#149343
>
>
>
Message 7
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| Subject: | Re: Throttle setting at higher cruising altitudes |
I think I'll just stick with backing the throttle off of the stop just
a tad. It doesn't appear to make a noticeable difference in power output
and it might also save a little wear and tear on the engine. Besides, it's
still just natural for me to back it off a bit after 1,700 hours of making
heat with J-52's that we could run all day at MIL minus 3%. I'll be in
black figures all of my life with my taxes after all the JP-4 and JP-5 I
got paid to burn!
Mark Davis
N44YK
----- Original Message -----
From: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E"
<mark.bitterlich@navy.mil>
Sent: Thursday, November 29, 2007 3:46 PM
Subject: RE: Yak-List: Re: Throttle setting at higher cruising altitudes
> MALS-14 64E" <mark.bitterlich@navy.mil>
>
> I did not have the instrumentation that Steve has when I came to the
> belief that I stated, and I tend to defer to his testing. However, this
> directly contradicts what Vladimir told me and I also trust HIS judgment
> beyond others as well!
>
> Makes me wonder if it might not be worthwhile to run the test again at
> altitude but with higher RPM settings. I wonder if Steve's test would
> duplicate at 10,000 feet and say 85% on the RPM? I would really like to
> know the answer to this for sure in case I have somehow managed to
> delude myself!
>
> Steve did say: "I think the most fuel efficient M-14 throttle setting
> for cruise is to set the throttle at the boost limit for any given RPM
> setting.
>
> To the best of my knowledge Steve, there are no "boost limits" to this
> engine at ANY RPM.
>
> Mark Bitterlich
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Mark Davis
> Sent: Thursday, November 29, 2007 17:25
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
>
>
> Steve and Mark,
> Thanks for the replies. I have noticed it appears to be a bit
> leaner when running at 65% vs. 70%. So, I've been running at 70% into
> headwinds and 65% with tailwinds.
>
> Mark Davis
> N44YK
>
> ----- Original Message -----
> From: "Mozam" <sdalton@hughes.net>
> To: <yak-list@matronics.com>
> Sent: Thursday, November 29, 2007 7:39 AM
> Subject: Yak-List: Re: Throttle setting at higher cruising altitudes
>
>
>>
>> I have a Fuel Scan unit in my TW that has proved to be very accurate.
>>
>> During high altitude cruise (say above 6,000'), I cannot detect any
>> evidence of this full throttle enrichment.
>>
>> For example, at 9,500' with the prop at 65%, I can place the throttle
> at
>> the forward stop, note the fuel flow, then retard the throttle until
> the
>> manifold pressure drops several inches (this is a couple inches of
>> throttle movement), and I see very little change in fuel flow.
>>
>> It appears to me that if there is any full throttle fuel enrichment,
> it is
>> "disengaged" at "higher" altitudes.
>>
>> Also, FWIW, I have found that RPM has a much greater effect on fuel
> flow
>> than manifold pressure (throttle position). In other words, pulling
> the
>> prop back from 70% to 65% reduces the fuel flow more than leaving the
> prop
>> at 70% and reducing the manifold pressure three or four inches.
>>
>> So at high altitude with a nice tailwind I pull the prop back to 60%
> and
>> put the throttle at the forward stop. This results in a fuel flow of
>> about 12.8 gal/hr.
>>
>> Just my opinion (based on my Fuel Scan observations), I think the most
>
>> fuel efficient M-14 throttle setting for cruise is to set the throttle
> at
>> the boost limit for any given RPM setting.
>>
>> Note: Your mileage may vary, past returns are no guarantee of future
>> returns, some assembly required, batteries not included, etc.
>>
>> Cheers,
>> Steve Dalton
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=149343#149343
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
Message 8
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Mark Bitterlich wrote;
> To the best of my knowledge Steve, there are no "boost limits" to this
> engine at ANY RPM.
>
> Mark Bitterlich
Mark;
There are varying RPM/manifold pressure limits for every engine with a
variable pitch propellor.
Probably the easiest (but not recommended) way to find the first one is to
attempt a take-off with the prop control at low RPM.
Walt
Message 9
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Really. Well Walt, I am not so sure you are right about that, but I am
always ready to stand corrected and learn something that I did not know
before.
My M-14 Manual says that you can operate this engine at full throttle
with the engine reduced to the very minimum RPM setting available at ANY
altitude. And ... I've read every available operating manual on this
engine that I can find.
So what is the limit you are speaking of with the M-14P ???
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
Sent: Thursday, November 29, 2007 18:19
Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
Mark Bitterlich wrote;
> To the best of my knowledge Steve, there are no "boost limits" to this
> engine at ANY RPM.
>
> Mark Bitterlich
Mark;
There are varying RPM/manifold pressure limits for every engine with a
variable pitch propellor.
Probably the easiest (but not recommended) way to find the first one is
to attempt a take-off with the prop control at low RPM.
Walt
Message 10
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| Subject: | Re: Throttle setting at higher cruising altitudes |
On Nov 29, 2007, at 6:39 AM, Mozam wrote:
> So at high altitude with a nice tailwind I pull the prop back to
> 60% and put the throttle at the forward stop. This results in a
> fuel flow of about 12.8 gal/hr.
>
> Just my opinion (based on my Fuel Scan observations), I think the
> most fuel efficient M-14 throttle setting for cruise is to set the
> throttle at the boost limit for any given RPM setting.
That is true for most recip engines, i.e. run maximum MAP to minimize
pumping losses and modulate RPM to control power output.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 11
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| Subject: | Re: Throttle setting at higher cruising altitudes |
mark.bitterlich(at)navy.m wrote:
> .
>
> To the best of my knowledge Steve, there are no "boost limits" to this
> engine at ANY RPM.
>
> Mark Bitterlich
> --
Hi Mark,
I agree, I have never seen any either.
Perhaps not the best choice of words on my part. What I was trying to say was
to use the max manifold pressure that the manual lists for a given power setting.
For example, the manual lists "Cruise 1" power as 64% RPM and 735 mmHg (29").
I *think* that using less than 735 mmHg in this case reduces engine efficiency.
But, I do not know if using more throttle would be an actual "over-boost" situation.
Cheers,
Steve
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=149456#149456
Message 12
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| Subject: | Re: Throttle setting at higher cruising altitudes |
mark.bitterlich(at)navy.m wrote:
> I did not have the instrumentation that Steve has when I came to the
> belief that I stated, and I tend to defer to his testing. However, this
> directly contradicts what Vladimir told me and I also trust HIS judgment
> beyond others as well!
>
> Makes me wonder if it might not be worthwhile to run the test again at
> altitude but with higher RPM settings. I wonder if Steve's test would
> duplicate at 10,000 feet and say 85% on the RPM? I would really like to
> know the answer to this for sure in case I have somehow managed to
> delude myself!
> --
Mark,
I agree, Vladimir (and others) have a wealth of knowledge about these engines.
I have only looked (and not found) this "max throttle enrichment" at high altitude.
Perhaps the carb only operates this feature at lower altitudes?
I will experiment further and report my findings. Any excuse to go fly is a good
one!! :D
Cheers,
Steve
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=149458#149458
Message 13
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| Subject: | Re: Thermodynamic efficiency (was: Re: Throttle setting at higher |
cruising altitudes)
This is one of those things that is well understood and it doesn't
really matter who says it, Vladimir notwithstanding.
HP output is going to be proportional to MAP and to RPM. If all other
things remain the same and you make a 10% reduction in manifold
pressure, you will get a 10% reduction in HP as you have reduced
available fuel/air by 10%.
Likewise, if you reduce RPM by 10% you are reducing the available
fuel and air by 10% as well, as the volume of fuel/air being pumped
into the cylinders by the cylinders is reduced by that amount too.
But several things happen that make this not quite linear. When you
close the throttle part way, the engine has to do more work to draw
in the fuel/air charge against the restriction caused by the throttle
valve. It also increases turbulence in the induction system. Both of
these reduce efficiency. Also, the cylinder pressure is lower while
the backpressure due to the ambient pressure remains the same. This
means that cylinder scavenging (getting rid of exhaust) is less
efficient. So, if you are seeking greatest efficiency, you need to
leave the throttle wide open.
Of course, the above assumes that we are operating the fuel/air
mixture at the most efficient as well. To extract maximum energy from
the fuel we must get complete combustion. That will only happen with
a mixture that is slightly on the lean side of peak EGT. (You need an
excess of O2 to make sure all the fuel molecules find O2 to combust
with.)
Now as for RPM, efficiency goes up when RPM goes down. Higher RPMs
produce higher frictional losses. Also, the higher flow rates in both
the induction and exhaust systems associated with higher RPMs reduce
efficiency as well. (The engine again experiences more pumping losses.)
So, you want to get the most "bang" for your gasoline "buck" the
solution is very simple:
1. Leave the throttle wide open. Climb to reduce MAP. This also gets
you a gain in TAS relative to dynamic pressure on the airframe (IAS).
2. Use the lowest RPM possible that will produce the desired speed.
3. Lean to a skosh lean of peak EGT. (Sorry, you can't do this in an
unmodified M14P.)
It appears to me that greatest efficiency would occur where you climb
to maximum altitude (engine producing only enough power to maintain
level flight at best L/D). That is certainly the most efficient
operating point for the airframe. I suspect that the engine will lose
enough efficiency by that point that one would get slightly better
efficiency at a little bit lower altitude. Still, going high is your
best bet for burning the least fuel possible on a long trip.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 14
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I'm wondering if there is an established TBO on the M14P or are there just general
guidelines based on inspection/ compressions.
In addition I"d like to get feedback from the group as to individual experience
in terms of service before overhaul did became necessary.
Thanks very much and thanks to the members of this forum for the exceptional
information I find here on a regular basis.
--------
Jack Snodgrass
4305 Claridge Ct.
Apex, NC 27539
808-371-2739
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=149461#149461
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Thanks Steve, I'll sure be interested in your results.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Mozam
Sent: Thursday, November 29, 2007 19:34
Subject: Yak-List: Re: Throttle setting at higher cruising altitudes
mark.bitterlich(at)navy.m wrote:
> I did not have the instrumentation that Steve has when I came to the
> belief that I stated, and I tend to defer to his testing. However,
> this directly contradicts what Vladimir told me and I also trust HIS
> judgment beyond others as well!
>
> Makes me wonder if it might not be worthwhile to run the test again at
> altitude but with higher RPM settings. I wonder if Steve's test would
> duplicate at 10,000 feet and say 85% on the RPM? I would really like
> to know the answer to this for sure in case I have somehow managed to
> delude myself!
> --
Mark,
I agree, Vladimir (and others) have a wealth of knowledge about these
engines.
I have only looked (and not found) this "max throttle enrichment" at
high altitude. Perhaps the carb only operates this feature at lower
altitudes?
I will experiment further and report my findings. Any excuse to go fly
is a good one!! :D
Cheers,
Steve
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=149458#149458
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| Subject: | Re: Throttle setting at higher cruising altitudes |
On Nov 29, 2007, at 3:49 PM, Bitterlich, Mark G CIV Det Cherry Point,
MALS-14 64E wrote:
> Point, MALS-14 64E" <mark.bitterlich@navy.mil>
>
> Really. Well Walt, I am not so sure you are right about that, but
> I am
> always ready to stand corrected and learn something that I did not
> know
> before.
>
> My M-14 Manual says that you can operate this engine at full throttle
> with the engine reduced to the very minimum RPM setting available
> at ANY
> altitude. And ... I've read every available operating manual on this
> engine that I can find.
>
> So what is the limit you are speaking of with the M-14P ???
I don't think there is one for the M14P or the Huosai. There are RPM
limits but not MAP limits (that one can reach).
But in general, peak cylinder pressures are a function of MAP. At
really low RPMs you can complete combustion at an earlier crank angle
before the combustion chamber volume has changed as much so you can
get higher peak cylinder pressures at high MAP and low RPM. This
translates into higher main bearing pressure due to combustion.
(OTOH, higher RPMs result in higher main bearing pressure due to
accelerating the moving mass.) So I can imagine an engine having a
max MAP spec for a lower RPM. I recall that this is the case for most
of the big radial engines. I suspect Pappy can name these limits for
the 1820 for us.
Regardless, you aren't going to hurt your M14P or Huosai engine by
leaving the throttle all the way forward and changing power by
changing RPM. The only question is whether or not there is an
enrichment circuit in the carb at full throttle. I think that having
a fuel-flow gauge and having it NOT show a noticeable reduction in
fuel flow when the throttle is pulled back a skosh puts this one to
bed also.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 17
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| Subject: | Re: Freon & on & on & on |
On Nov 29, 2007, at 11:25 AM, Jon Boede wrote:
> I am under the delusion that putting a shot of Freon into said
> system and sniffing with the leak detector is a good way to find
> all the leaks.
It should work.
> But, being the non-chemist that I am, I thought I'd ask around
> first before I do something ignorant. :-)
>
> I read through the list of refrigerants and it looks like R-23
> (trifluoromethane / Fluoroform) or R-503 (R-13/R-23 mix) has a
> sufficiently high vapor pressure (about 4.4 MPa) at room
> temperature that I can pump some of the Freon into an empty
> nitrogen pony bottle, bump it up with nitrogen and then run the
> whole system up to a pretty good pressure without the Freon turning
> into a liquid.
Ha, I hadn't thought of the CFC going to liquid at operating
pressure. Good point.
> Anybody have any objections to all this? Is running CFCs or HFCs
> into aluminum tubing a bad idea?
It won't hurt a thing. What do you think they do in the condenser
coil of your A/C?
> In some systems (e.g. L-39) the nitrogen system also supplies head
> pressure to the hydraulic system. Is mixing CFCs/HFCs and MIL-5606
> a bad idea?
CFCs are inert. They won't react with the hydraulic fluid. Air with
its 20% O2 is a lot more reactive, especially under pressure, which
is why they use N2 instead of air.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 18
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| Subject: | Re: Freon & on & on & on |
On Nov 29, 2007, at 11:52 AM, Cliff Coy wrote:
>
> Most leak detectors do not react with the freon (a very inert gas),
> but actually detect the ultrasonic sound the leak makes.
There are both types, i.e. chemical and sonic.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 19
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| Subject: | Re: Throttle setting at higher cruising altitudes |
This is not a reply to your posting Brian, but just a reply in general.
In my earlier post, I did not mean to imply that manifold / RPM
relationships were unrestricted on EVERY airplane, just that such
restrictions did not always exist for any engine with a variable pitch
prop as Walt was mentioning. I distinctly remember reading that you can
be at full power on the M-14P, and I mean WFO, and pull the prop back to
ANY RPM setting while leaving the throttle wide open. This surprised me
enough that I questioned it and had it verified by a number of both
written and verbal (all Russian) sources. But if anyone has any written
source that specifies differently, I would be happy to be proven wrong.
This is to me not a matter of who is right and who is wrong, but WHAT is
right and WHAT is wrong.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Brian Lloyd
Sent: Thursday, November 29, 2007 19:48
Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
On Nov 29, 2007, at 3:49 PM, Bitterlich, Mark G CIV Det Cherry Point,
MALS-14 64E wrote:
> Point, MALS-14 64E" <mark.bitterlich@navy.mil>
>
> Really. Well Walt, I am not so sure you are right about that, but
> I am
> always ready to stand corrected and learn something that I did not
> know
> before.
>
> My M-14 Manual says that you can operate this engine at full throttle
> with the engine reduced to the very minimum RPM setting available
> at ANY
> altitude. And ... I've read every available operating manual on this
> engine that I can find.
>
> So what is the limit you are speaking of with the M-14P ???
I don't think there is one for the M14P or the Huosai. There are RPM
limits but not MAP limits (that one can reach).
But in general, peak cylinder pressures are a function of MAP. At
really low RPMs you can complete combustion at an earlier crank angle
before the combustion chamber volume has changed as much so you can
get higher peak cylinder pressures at high MAP and low RPM. This
translates into higher main bearing pressure due to combustion.
(OTOH, higher RPMs result in higher main bearing pressure due to
accelerating the moving mass.) So I can imagine an engine having a
max MAP spec for a lower RPM. I recall that this is the case for most
of the big radial engines. I suspect Pappy can name these limits for
the 1820 for us.
Regardless, you aren't going to hurt your M14P or Huosai engine by
leaving the throttle all the way forward and changing power by
changing RPM. The only question is whether or not there is an
enrichment circuit in the carb at full throttle. I think that having
a fuel-flow gauge and having it NOT show a noticeable reduction in
fuel flow when the throttle is pulled back a skosh puts this one to
bed also.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 20
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| Subject: | Freon & on & on & on |
Brian! Sorry... I just could not resist!
You said: "There are both types, i.e. chemical and sonic".
Didn't you mean: "There are both types, i.e. chemical and ULTRAsonic".
???
I just know I'm going to love this answer!
Your bud,
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Brian Lloyd
Sent: Thursday, November 29, 2007 19:54
Subject: Re: Yak-List: Freon & on & on & on
On Nov 29, 2007, at 11:52 AM, Cliff Coy wrote:
>
> Most leak detectors do not react with the freon (a very inert gas),
> but actually detect the ultrasonic sound the leak makes.
There are both types, i.e. chemical and sonic.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 21
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| Subject: | Re: Freon & on & on & on |
On Nov 29, 2007, at 5:04 PM, Bitterlich, Mark G CIV Det Cherry Point,
MALS-14 64E wrote:
> Point, MALS-14 64E" <mark.bitterlich@navy.mil>
>
> Brian! Sorry... I just could not resist!
>
> You said: "There are both types, i.e. chemical and sonic".
>
> Didn't you mean: "There are both types, i.e. chemical and
> ULTRAsonic".
> ???
>
> I just know I'm going to love this answer!
Sonic. Vibrations in the air. Frequency is not the issue. If you want
to use the word "ultrasonic" to mean that the vibrations are outside
the range of normal human hearing, that's fine with me. Regardless,
one works by detecting the molecules of some CFC and the other works
by detecting the vibrations in the air caused by the escaping high-
pressure gas, i.e. by detecting a sound.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 22
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Hi Mark;
I don't have the M14P manual to refer to but Steve has just posted the
Cruise 1 setting of 64% and 735 mm/hg. This is a recommended limit.
Granted that as altitude increases the throttle must be opened to maintain
the desired MP. Since these engines have a low blower ratio compared to an
"altitude" engine the full throttle altitude will be reached very quickly.
In fact it is actually sea level but only with the power settings given in
the manual.
I absolutely agree with Steve's first post to use max. manifold pressure for
a given RPM. He has revised it a bit to a given power setting rather than
RPM but I think he means the same. The "power setting" is a combination of
RPM and MP.
I'm sure you would agree that at sea level a power setting of full throttle
and 1450 (50%)RPM could be fairly described as over boosted.
Cheers;
Walt
----- Original Message -----
From: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E"
<mark.bitterlich@navy.mil>
Sent: Thursday, November 29, 2007 3:49 PM
Subject: RE: Yak-List: Re: Throttle setting at higher cruising altitudes
> MALS-14 64E" <mark.bitterlich@navy.mil>
>
> Really. Well Walt, I am not so sure you are right about that, but I am
> always ready to stand corrected and learn something that I did not know
> before.
>
> My M-14 Manual says that you can operate this engine at full throttle
> with the engine reduced to the very minimum RPM setting available at ANY
> altitude. And ... I've read every available operating manual on this
> engine that I can find.
>
> So what is the limit you are speaking of with the M-14P ???
>
> Mark
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
> Sent: Thursday, November 29, 2007 18:19
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
>
>
> Mark Bitterlich wrote;
>
>> To the best of my knowledge Steve, there are no "boost limits" to this
>
>> engine at ANY RPM.
>>
>> Mark Bitterlich
>
> Mark;
>
> There are varying RPM/manifold pressure limits for every engine with a
> variable pitch propellor.
> Probably the easiest (but not recommended) way to find the first one is
> to attempt a take-off with the prop control at low RPM.
>
> Walt
>
>
>
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The Soviet System required overhaul of the entire aircraft every 500hrs
or 5 years.
Engines, being part of the aircraft were subject to the same rules.
After the forth overhaul the engine was scrapped.
On the data plate of each engine is a place to stamp the overhaul-
usually a roman numeral to identify how many overhauls the engine has
received.
Motorstar, one of the manufacturers of these engines, has a recommended
TBO of 1500hrs.
Like Lycoming and Continental, this is not a guarantee that the engine
will run to TBO, but *should* be overhauled at this time.
My experience has found that most engines suffer from old age or mishap
long before they're worn out.
Most notably the rubber and non-metallic parts degrade quite rapidly
after 7-8 years of age.
The ignition harnesses are very prone to breakdown.
I recommend replacing the harnesses with BIW 5mm steel core silicone
wiring.
We purchase it from Savage Magneto in California.
I know of two Yak-52TW with more than 650hrs that are running strong.
so...use it or lose it -grin-
Cheers,
Cliff
B747crew wrote:
>
> I'm wondering if there is an established TBO on the M14P or are there just general
guidelines based on inspection/ compressions.
> In addition I"d like to get feedback from the group as to individual experience
in terms of service before overhaul did became necessary.
> Thanks very much and thanks to the members of this forum for the exceptional
information I find here on a regular basis.
>
> --------
> Jack Snodgrass
> 4305 Claridge Ct.
> Apex, NC 27539
> 808-371-2739
>
>
>
--
Clifford Coy
Director of Maintenance
Border Air Ltd
629 Airport Rd.
Swanton, VT 05488
802-868-2822 TEL
802-868-4465 FAX
Skype: callto:Cliff.Coy <callto:cliff.coy>
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| Subject: | Freon & on & on & on |
On Nov 29, 2007, at 8:294 PM, Brian Lloyd <brian-1927@lloyd.com> wrote:
>Sonic. Vibrations in the air. Frequency is not the issue. If you want
>to use the word "ultrasonic" to mean that the vibrations are outside
>the range of normal human hearing, that's fine with me. Regardless,
>one works by detecting the molecules of some CFC and the other works
>by detecting the vibrations in the air caused by the escaping high-
>pressure gas, i.e. by detecting a sound.
Brian, I was just messing with you honestly. But..... Being somewhat
particular in the vein of accuracy as we both tend to be at times... In
fact to the point of sometimes verging on anal, at least in my case
(yes, I admit it!)
First of all, I agree that your description is in fact perfectly
accurate with a minor exception, that being:
"Sonic: Vibrations in the air. Frequency is not the issue."
Quoting Merriam Webster:
Sonic: having a frequency within the audibility range of the human ear
-used of waves and vibrations
Ultrasonic: having a frequency above the human ear's audibility limit
of about 20,000 hertz -used of waves and vibrations
Gaseous leak detectors that do not rely on chemical detection but rather
waves of sound coming from compressed air leaks most typically operate
in the Ultrasonic range since the sound said leaks produce are maximum
in this range, and further detection above sonic makes them easier to
isolate.
So Sir, small point as it remains... Frequency is the issue. Because
the sound detector used is not sonic, but in fact ultrasonic. If you
take the detector from one of these devices it in fact typically has a
headset and a microphone. If you speak into the mike, you will not hear
a darn thing coming out of your headset per se. Compress your mouth and
blow air out and the story changes! I've used them all of my adult life.
I agree that your description is in fact perfectly accurate
Hey... You would have nailed me if the roles were reversed! :-) And
yes.. It is a ridiculous point.
Mark Bitterlich
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Brian Lloyd
Sent: Thursday, November 29, 2007 20:23
Subject: Re: Yak-List: Freon & on & on & on
> Point, MALS-14 64E" <mark.bitterlich@navy.mil>
>
> Brian! Sorry... I just could not resist!
>
> You said: "There are both types, i.e. chemical and sonic".
>
> Didn't you mean: "There are both types, i.e. chemical and
> ULTRAsonic".
> ???
>
> I just know I'm going to love this answer!
Sonic. Vibrations in the air. Frequency is not the issue. If you want
to use the word "ultrasonic" to mean that the vibrations are outside
the range of normal human hearing, that's fine with me. Regardless,
one works by detecting the molecules of some CFC and the other works
by detecting the vibrations in the air caused by the escaping high-
pressure gas, i.e. by detecting a sound.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 25
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| Subject: | Re: Throttle setting at higher cruising altitudes |
In a message dated 11/29/2007 5:34:25 P.M. Pacific Standard Time,
wlannon@persona.ca writes:
absolutely agree with Steve's first post to use max. manifold pressure for
a given RPM. He has revised it a bit to a given power setting rather than
RPM but I think he means the same. The "power setting" is a combination of
RPM and MP.
I'm sure you would agree that at sea level a power setting of full throttle
and 1450 (50%)RPM could be fairly described as over boosted.
Cheers;
Walt
Walt, does not the Cj-6A manual say that Max power is 2350 rpm M/P ambient +
85 mm ?
Tom Elliott
CJ-6 NX63727
Sandy Valley NV
3L2
702-723-1223
**************************************Check out AOL's list of 2007's hottest
products.
(http://money.aol.com/special/hot-products-2007?NCID=aoltop00030000000001)
Message 26
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Hi Tom;
Yep. But referring on this thread to the M14P. Trust all is well with you.
Best:
Walt
----- Original Message -----
From: N13472@aol.com
To: yak-list@matronics.com
Sent: Thursday, November 29, 2007 6:44 PM
Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
In a message dated 11/29/2007 5:34:25 P.M. Pacific Standard Time, wlannon@persona.ca
writes:
absolutely agree with Steve's first post to use max. manifold pressure for
a given RPM. He has revised it a bit to a given power setting rather than
RPM but I think he means the same. The "power setting" is a combination of
RPM and MP.
I'm sure you would agree that at sea level a power setting of full throttle
and 1450 (50%)RPM could be fairly described as over boosted.
Cheers;
Walt
Walt, does not the Cj-6A manual say that Max power is 2350 rpm M/P ambient +
85 mm ?
Tom Elliott
CJ-6 NX63727
Sandy Valley NV
3L2
702-723-1223
------------------------------------------------------------------------------
Check out AOL Money & Finance's list of the hottest products and top money wasters
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| Subject: | Skycatcher to be made in China |
So....Cessna figured out that the Chinese can build an airplane!! All I want to
know is - will it be painted with lead paint???
Craig
CJ6 - N8100C
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=149494#149494
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|
There is not a published TBO for the M-14 to my knowledge. It generally
flown for 500 hours with pretty much doing minimal maintenance adding oil
ect. It then underwent an IRAN at depot where what was out of tolerance was
replaced.
Doc
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of B747crew
Sent: Thursday, November 29, 2007 6:40 PM
Subject: Yak-List: M14 P TBO
I'm wondering if there is an established TBO on the M14P or are there just
general guidelines based on inspection/ compressions.
In addition I"d like to get feedback from the group as to individual
experience in terms of service before overhaul did became necessary.
Thanks very much and thanks to the members of this forum for the
exceptional information I find here on a regular basis.
--------
Jack Snodgrass
4305 Claridge Ct.
Apex, NC 27539
808-371-2739
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=149461#149461
Message 29
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Huh?
Doc
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Mark Davis
Sent: Thursday, November 29, 2007 4:25 PM
Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
Steve and Mark,
Thanks for the replies. I have noticed it appears to be a bit leaner
when running at 65% vs. 70%. So, I've been running at 70% into headwinds
and 65% with tailwinds.
Mark Davis
N44YK
----- Original Message -----
From: "Mozam" <sdalton@hughes.net>
Sent: Thursday, November 29, 2007 7:39 AM
Subject: Yak-List: Re: Throttle setting at higher cruising altitudes
>
> I have a Fuel Scan unit in my TW that has proved to be very accurate.
>
> During high altitude cruise (say above 6,000'), I cannot detect any
> evidence of this full throttle enrichment.
>
> For example, at 9,500' with the prop at 65%, I can place the throttle at
> the forward stop, note the fuel flow, then retard the throttle until the
> manifold pressure drops several inches (this is a couple inches of
> throttle movement), and I see very little change in fuel flow.
>
> It appears to me that if there is any full throttle fuel enrichment, it is
> "disengaged" at "higher" altitudes.
>
> Also, FWIW, I have found that RPM has a much greater effect on fuel flow
> than manifold pressure (throttle position). In other words, pulling the
> prop back from 70% to 65% reduces the fuel flow more than leaving the prop
> at 70% and reducing the manifold pressure three or four inches.
>
> So at high altitude with a nice tailwind I pull the prop back to 60% and
> put the throttle at the forward stop. This results in a fuel flow of
> about 12.8 gal/hr.
>
> Just my opinion (based on my Fuel Scan observations), I think the most
> fuel efficient M-14 throttle setting for cruise is to set the throttle at
> the boost limit for any given RPM setting.
>
> Note: Your mileage may vary, past returns are no guarantee of future
> returns, some assembly required, batteries not included, etc.
>
> Cheers,
> Steve Dalton
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=149343#149343
>
>
>
Message 30
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Doc,
I use 65% to take the free ride of the tailwind. 70% to reduce the time
the headwind has to work on me. Navy technique we used. In significant
headwinds we always ran at near military power settings. Max endurance AOA
with a strong tailwind when trying to stretch range.
Mark Davis
N44YK
----- Original Message -----
From: "Roger Kemp" <viperdoc@mindspring.com>
Sent: Thursday, November 29, 2007 7:59 PM
Subject: RE: Yak-List: Re: Throttle setting at higher cruising altitudes
>
> Huh?
> Doc
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Mark Davis
> Sent: Thursday, November 29, 2007 4:25 PM
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
>
>
> Steve and Mark,
> Thanks for the replies. I have noticed it appears to be a bit leaner
> when running at 65% vs. 70%. So, I've been running at 70% into headwinds
> and 65% with tailwinds.
>
> Mark Davis
> N44YK
>
> ----- Original Message -----
> From: "Mozam" <sdalton@hughes.net>
> To: <yak-list@matronics.com>
> Sent: Thursday, November 29, 2007 7:39 AM
> Subject: Yak-List: Re: Throttle setting at higher cruising altitudes
>
>
>>
>> I have a Fuel Scan unit in my TW that has proved to be very accurate.
>>
>> During high altitude cruise (say above 6,000'), I cannot detect any
>> evidence of this full throttle enrichment.
>>
>> For example, at 9,500' with the prop at 65%, I can place the throttle at
>> the forward stop, note the fuel flow, then retard the throttle until the
>> manifold pressure drops several inches (this is a couple inches of
>> throttle movement), and I see very little change in fuel flow.
>>
>> It appears to me that if there is any full throttle fuel enrichment, it
>> is
>
>> "disengaged" at "higher" altitudes.
>>
>> Also, FWIW, I have found that RPM has a much greater effect on fuel flow
>> than manifold pressure (throttle position). In other words, pulling the
>> prop back from 70% to 65% reduces the fuel flow more than leaving the
>> prop
>
>> at 70% and reducing the manifold pressure three or four inches.
>>
>> So at high altitude with a nice tailwind I pull the prop back to 60% and
>> put the throttle at the forward stop. This results in a fuel flow of
>> about 12.8 gal/hr.
>>
>> Just my opinion (based on my Fuel Scan observations), I think the most
>> fuel efficient M-14 throttle setting for cruise is to set the throttle at
>> the boost limit for any given RPM setting.
>>
>> Note: Your mileage may vary, past returns are no guarantee of future
>> returns, some assembly required, batteries not included, etc.
>>
>> Cheers,
>> Steve Dalton
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=149343#149343
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
Message 31
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| Subject: | Re: Throttle setting at higher cruising altitudes |
>I don't have the M14P manual to refer to but Steve has just posted the
Cruise 1 setting of 64% and 735 mm/hg. This is a recommended limit.
Walt, I am sorry... No it is not a recommended limit. It is performance
setting where you should get documented results. It is like a Vx or Vy
speed. You climb at those speeds at a given weight, and you should
obtain a known end. These are not limits. Because the manual documents
a Cruise 1 setting and a Cruise 2 setting, that these are the only two
places that you are allowed to cruise? No Sir. My manual clearly
states that full throttle is available at ANY RPM SETTING. When I get
home tonight, I will pull it out and find it and quote it.
>Granted that as altitude increases the throttle must be opened to
maintain the desired MP. Since these engines have a low blower ratio
compared to an "altitude" engine the full throttle altitude will be
reached very quickly.
In fact it is actually sea level but only with the power settings given
in the manual.
I absolutely agree with Steve's first post to use max. manifold pressure
for a given RPM. He has revised it a bit to a given power setting rather
than RPM but I think he means the same. The "power setting" is a
combination of RPM and MP.
I'm sure you would agree that at sea level a power setting of full
throttle and 1450 (50%)RPM could be fairly described as over boosted.
I understand that we both understand how manifold pressure works and are
not disagreeing over nonsense. But actually no Walt I would not
consider 55 or 60% RPM (mine simply will not go that low at full
throttle) with full throttle to be "over-boosted". I honestly do not
usually run it all the way down to 60% with full throttle, but I do it
regularly at 70%. I have run for an hour at 1000 feet with 70% RPM and
full throttle. Sounds good, runs good.
Consider if you will that some of the big blowers on some of the heavy
iron birds out there are/were capable of well over 50 inches of "boost".
Some of them would go so high that water injection was used. Now we
have an engine turning 2950 RPM developing a few thousand horsepower in
this condition. This was not considered "over-boosted".
Then we have an engine which has a max horsepower of 360 that develops
around 34 or so inches of manifold pressure at sea level (plus or minus
2 inches or so), and we apply that to an engine turning say 1500 or so
RPM, and this is suddenly over-boosted simply because it used the same
manifold pressure at a higher RPM?
Do I feel that there are no limits? Well, certainly there are with some
motors, but apparently not with the M-14P because the books that I have
read specifically says otherwise.
This is a much better discussion than most lately by the way... It has
serious bearing on how we all fly.
Mark
----- Original Message -----
From: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E"
<mark.bitterlich@navy.mil>
Sent: Thursday, November 29, 2007 3:49 PM
Subject: RE: Yak-List: Re: Throttle setting at higher cruising altitudes
Point,
> MALS-14 64E" <mark.bitterlich@navy.mil>
>
> Really. Well Walt, I am not so sure you are right about that, but I
am
> always ready to stand corrected and learn something that I did not
know
> before.
>
> My M-14 Manual says that you can operate this engine at full throttle
> with the engine reduced to the very minimum RPM setting available at
ANY
> altitude. And ... I've read every available operating manual on this
> engine that I can find.
>
> So what is the limit you are speaking of with the M-14P ???
>
> Mark
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter
Lannon
> Sent: Thursday, November 29, 2007 18:19
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Re: Throttle setting at higher cruising
altitudes
>
>
> Mark Bitterlich wrote;
>
>> To the best of my knowledge Steve, there are no "boost limits" to
this
>
>> engine at ANY RPM.
>>
>> Mark Bitterlich
>
> Mark;
>
> There are varying RPM/manifold pressure limits for every engine with a
> variable pitch propellor.
> Probably the easiest (but not recommended) way to find the first one
is
> to attempt a take-off with the prop control at low RPM.
>
> Walt
>
>
>
Message 32
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| Subject: | Re: Throttle setting at higher cruising altitudes |
I am looking at "exploitation parameters with respect to the Running
Conditions" as stated in the translated "IAK 52 School and Training Aircraft
Flight Manual".
Walt is absolutely correct for the Cruise 1 that Mozam referred to is for
sea level operating parameters as best I can tell. Remember as you climb in
altitude the atmospheric pressure decreases so to maintain the same manifold
pressure and approximate HP, you have to open the advance (the inboard
manifold pressure lever). Not to be too simple here.
Running Condition.....Engine Speed (%)....Pressure Of Air @ engine intake
(mmHg col.).....Fuel Spec. Consumption(g/hP.hr)
Cruise 1................64 +/-1..........................735 +/-
15..........................215-235
Cruise 2................59 +/-1..........................670 +/-
15..........................210-230
Nominal 1...............70 +/-1..........................75-15
(over)........................265-300
Nominal 2...............82 +/-1..........................95-15
(over)........................280-310
T-O ...............99 +/-1..........................125-15
(over).......................285-315
Here is a table that gives the atmospheric pressure at various altitudes.
The altitude is given in feet and the pressure is in inches of mercury.
Altitude Pressure Altitude Pressure
0,000 29.92 20,000 13.75
1,000 28.86 25,000 11.10
2,000 27.82 30,000 8.886
3,000 26.82 35.000 7.041
4,000 25.84 40,000 5.538
5,000 24.89 45,000 4.355
10,000 20.58 50,000 3.425
15,000 16.88 60,000 2.118
18,000 * 14.94 100,000 0.329
* This is almost exactly one-half the sea-level value.
To convert in/Hg to psi, multiply by 0.491.
@ 18,000 ft = 1/2 atm, @ 35,000 ft = 1/5 atm (atmosphere)
Pressure Equivalents:
1 Atmosphere (as a unit of pressure) = 14.7 psi = 34 ft water column = 76
cm/Hg
= 29.92 in/Hg = 1.013 bar = 1,013 mbar
1 bar = 1,000 mbar = 14.5 psi = 29.53 in/Hg = 0.9869 atm
1 psi = 27.68 inches water column = 2.036 in/Hg = 6.859 kPa
1 kPa = 1,000 Pascals = 0.1458 psi
Brain and Steve eloquently said it in their earlier post. Open the advance
to maintain airflow and hp at a given altitude since the barometric pressure
is decreasing as altitude increases.
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
Sent: Thursday, November 29, 2007 7:30 PM
Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
Hi Mark;
I don't have the M14P manual to refer to but Steve has just posted the
Cruise 1 setting of 64% and 735 mm/hg. This is a recommended limit.
Granted that as altitude increases the throttle must be opened to maintain
the desired MP. Since these engines have a low blower ratio compared to an
"altitude" engine the full throttle altitude will be reached very quickly.
In fact it is actually sea level but only with the power settings given in
the manual.
I absolutely agree with Steve's first post to use max. manifold pressure for
a given RPM. He has revised it a bit to a given power setting rather than
RPM but I think he means the same. The "power setting" is a combination of
RPM and MP.
I'm sure you would agree that at sea level a power setting of full throttle
and 1450 (50%)RPM could be fairly described as over boosted.
Cheers;
Walt
----- Original Message -----
From: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E"
<mark.bitterlich@navy.mil>
Sent: Thursday, November 29, 2007 3:49 PM
Subject: RE: Yak-List: Re: Throttle setting at higher cruising altitudes
> MALS-14 64E" <mark.bitterlich@navy.mil>
>
> Really. Well Walt, I am not so sure you are right about that, but I am
> always ready to stand corrected and learn something that I did not know
> before.
>
> My M-14 Manual says that you can operate this engine at full throttle
> with the engine reduced to the very minimum RPM setting available at ANY
> altitude. And ... I've read every available operating manual on this
> engine that I can find.
>
> So what is the limit you are speaking of with the M-14P ???
>
> Mark
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
> Sent: Thursday, November 29, 2007 18:19
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
>
>
> Mark Bitterlich wrote;
>
>> To the best of my knowledge Steve, there are no "boost limits" to this
>
>> engine at ANY RPM.
>>
>> Mark Bitterlich
>
> Mark;
>
> There are varying RPM/manifold pressure limits for every engine with a
> variable pitch propellor.
> Probably the easiest (but not recommended) way to find the first one is
> to attempt a take-off with the prop control at low RPM.
>
> Walt
>
>
>
Message 33
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| Subject: | Freon & on & on & on |
And there are the ones that were left aboard the Concorde. Those were SUPE
Rsonic leak detectors.> Subject: RE: Yak-List: Freon & on & on & on> Date:
Thu, 29 Nov 2007 21:07:04 -0500> From: mark.bitterlich@navy.mil> To: yak-li
Det Cherry Point, MALS-14 64E" <mark.bitterlich@navy.mil>> > On Nov 29, 20
07, at 8:294 PM, Brian Lloyd <brian-1927@lloyd.com> wrote:> > > >Sonic. Vib
rations in the air. Frequency is not the issue. If you want > >to use the w
ord "ultrasonic" to mean that the vibrations are outside > >the range of no
rmal human hearing, that's fine with me. Regardless, > >one works by detect
ing the molecules of some CFC and the other works > >by detecting the vibra
tions in the air caused by the escaping high- > >pressure gas, i.e. by dete
cting a sound.> > Brian, I was just messing with you honestly. But..... Bei
ng somewhat> particular in the vein of accuracy as we both tend to be at ti
mes... In> fact to the point of sometimes verging on anal, at least in my c
ase> (yes, I admit it!) > > First of all, I agree that your description is
in fact perfectly> accurate with a minor exception, that being: > "Sonic: V
ibrations in the air. Frequency is not the issue." > > Quoting Merriam Webs
ter: > Sonic: having a frequency within the audibility range of the human e
ar> -used of waves and vibrations > > Ultrasonic: having a frequency above
the human ear's audibility limit> of about 20,000 hertz -used of waves and
vibrations > > Gaseous leak detectors that do not rely on chemical detectio
n but rather> waves of sound coming from compressed air leaks most typicall
y operate> in the Ultrasonic range since the sound said leaks produce are m
aximum> in this range, and further detection above sonic makes them easier
to> isolate. > > So Sir, small point as it remains... Frequency is the issu
e. Because> the sound detector used is not sonic, but in fact ultrasonic. I
f you> take the detector from one of these devices it in fact typically has
a> headset and a microphone. If you speak into the mike, you will not hear
> a darn thing coming out of your headset per se. Compress your mouth and>
blow air out and the story changes! I've used them all of my adult life.> I
agree that your description is in fact perfectly accurate > > Hey... You w
ould have nailed me if the roles were reversed! :-) And> yes.. It is a ridi
culous point. > > Mark Bitterlich> > > > > > -----Original Message-----> Fr
om: owner-yak-list-server@matronics.com> [mailto:owner-yak-list-server@matr
onics.com] On Behalf Of Brian Lloyd> Sent: Thursday, November 29, 2007 20:2
3> To: yak-list@matronics.com> Subject: Re: Yak-List: Freon & on & on & on>
oint, MALS-14 64E" <mark.bitterlich@navy.mil>> >> > Brian! Sorry... I just
could not resist!> >> > You said: "There are both types, i.e. chemical and
sonic".> >> > Didn't you mean: "There are both types, i.e. chemical and > >
ULTRAsonic".> > ???> >> > I just know I'm going to love this answer!> > So
nic. Vibrations in the air. Frequency is not the issue. If you want > to us
e the word "ultrasonic" to mean that the vibrations are outside > the range
of normal human hearing, that's fine with me. Regardless, > one works by d
etecting the molecules of some CFC and the other works > by detecting the v
ibrations in the air caused by the escaping high- > pressure gas, i.e. by d
etecting a sound.> > Brian Lloyd 3191 Western Drive> brianl AT lloyd DOT co
m Cameron Park, CA 95682> +1.916.367.2131 (voice) +1.270.912.0788 (fax)> >
PGP key ID: 12095C52A32A1B6C> PGP key fingerprint: 3B1D BA11 4913 3254 B6E0
============> > >
Message 34
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| Subject: | Re: Throttle setting at higher cruising altitudes |
Copy. Kinda thought that was what you meant.
Doc
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Mark Davis
Sent: Thursday, November 29, 2007 9:55 PM
Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
Doc,
I use 65% to take the free ride of the tailwind. 70% to reduce the time
the headwind has to work on me. Navy technique we used. In significant
headwinds we always ran at near military power settings. Max endurance AOA
with a strong tailwind when trying to stretch range.
Mark Davis
N44YK
----- Original Message -----
From: "Roger Kemp" <viperdoc@mindspring.com>
Sent: Thursday, November 29, 2007 7:59 PM
Subject: RE: Yak-List: Re: Throttle setting at higher cruising altitudes
>
> Huh?
> Doc
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Mark Davis
> Sent: Thursday, November 29, 2007 4:25 PM
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Re: Throttle setting at higher cruising altitudes
>
>
> Steve and Mark,
> Thanks for the replies. I have noticed it appears to be a bit leaner
> when running at 65% vs. 70%. So, I've been running at 70% into headwinds
> and 65% with tailwinds.
>
> Mark Davis
> N44YK
>
> ----- Original Message -----
> From: "Mozam" <sdalton@hughes.net>
> To: <yak-list@matronics.com>
> Sent: Thursday, November 29, 2007 7:39 AM
> Subject: Yak-List: Re: Throttle setting at higher cruising altitudes
>
>
>>
>> I have a Fuel Scan unit in my TW that has proved to be very accurate.
>>
>> During high altitude cruise (say above 6,000'), I cannot detect any
>> evidence of this full throttle enrichment.
>>
>> For example, at 9,500' with the prop at 65%, I can place the throttle at
>> the forward stop, note the fuel flow, then retard the throttle until the
>> manifold pressure drops several inches (this is a couple inches of
>> throttle movement), and I see very little change in fuel flow.
>>
>> It appears to me that if there is any full throttle fuel enrichment, it
>> is
>
>> "disengaged" at "higher" altitudes.
>>
>> Also, FWIW, I have found that RPM has a much greater effect on fuel flow
>> than manifold pressure (throttle position). In other words, pulling the
>> prop back from 70% to 65% reduces the fuel flow more than leaving the
>> prop
>
>> at 70% and reducing the manifold pressure three or four inches.
>>
>> So at high altitude with a nice tailwind I pull the prop back to 60% and
>> put the throttle at the forward stop. This results in a fuel flow of
>> about 12.8 gal/hr.
>>
>> Just my opinion (based on my Fuel Scan observations), I think the most
>> fuel efficient M-14 throttle setting for cruise is to set the throttle at
>> the boost limit for any given RPM setting.
>>
>> Note: Your mileage may vary, past returns are no guarantee of future
>> returns, some assembly required, batteries not included, etc.
>>
>> Cheers,
>> Steve Dalton
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=149343#149343
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
Message 35
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| Subject: | Re: Throttle setting at higher cruising altitudes |
On Nov 29, 2007, at 6:44 PM, N13472@aol.com wrote:
> In a message dated 11/29/2007 5:34:25 P.M. Pacific Standard Time,
> wlannon@persona.ca writes:
> absolutely agree with Steve's first post to use max. manifold
> pressure for
> a given RPM. He has revised it a bit to a given power setting
> rather than
> RPM but I think he means the same. The "power setting" is a
> combination of
> RPM and MP.
> I'm sure you would agree that at sea level a power setting of full
> throttle
> and 1450 (50%)RPM could be fairly described as over boosted.
>
> Cheers;
> Walt
>
>
> Walt, does not the Cj-6A manual say that Max power is 2350 rpm M/P
> ambient + 85 mm ?
Yes.
It also says that you may maintain that for 5 minutes. If you want to
run for an hour it is 2250 and ambient + 80mm, after which you must
give the engine a five-minute rest. If you want to run continuously
it is 710mm and 2250 RPM.
FWIW I used to run my Huosai at 1850 RPM and full-throttle from sea-
level to whatever.
--
Brian Lloyd 3191 Western Drive
brian HYPHEN 1927 AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
Message 36
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| Subject: | Re: Throttle setting at higher cruising altitudes |
On Nov 29, 2007, at 7:55 PM, Mark Davis wrote:
>
> Doc,
> I use 65% to take the free ride of the tailwind. 70% to reduce
> the time the headwind has to work on me. Navy technique we used.
> In significant headwinds we always ran at near military power
> settings. Max endurance AOA with a strong tailwind when trying to
> stretch range.
Yes. Max endurance AoA is best L/D. The AoA indicator makes it easy
to find.
--
Brian Lloyd 3191 Western Drive
brian HYPHEN 1927 AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
Antoine de Saint-Exupry
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
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