Today's Message Index:
----------------------
1. 08:47 AM - In reply to Bill Halverson (Richard Goode)
2. 11:17 AM - Re: MAP and RPM (was: range) (Sam Sax)
3. 11:36 AM - Re: In reply to Bill Halverson (Bill Halverson)
4. 11:36 AM - Re: In reply to Bill Halverson (Bill Halverson)
5. 12:37 PM - sticking PRV (Mark Jefferies YAK UK Ltd)
6. 03:25 PM - Operating Restrictions - Help! (cpayne@joimail.com)
7. 04:16 PM - Re: In reply to Bill Halverson Richard Goode (Gus Fraser)
8. 05:16 PM - Re: Operating Restrictions - Help! (A. Dennis Savarese)
9. 07:52 PM - Re: Request from the Smoking Section..... (Dee Grimm)
10. 08:07 PM - Re: Request from the Smoking Section..... (cjpilot710@aol.com)
11. 08:19 PM - Re: MAP and RPM (was: range) (Dee Grimm)
12. 09:10 PM - Re: MAP and RPM (was: range) (cjpilot710@aol.com)
Message 1
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| Subject: | In reply to Bill Halverson |
MIME_MISSING_BOUNDARY 1.33)
--> Yak-List message posted by: "Richard Goode" <richard.goode@russianaeros.com>
In reply to Bill Halverson:
a.. The AK-14P carburettor is extremely complicated, but correct adjustment can
make a huge difference to the way the engine runs.
b.. For lower-power cruise there is straightforward adjustment with the metering
needle screw.
c.. For take-off and higher power, the adjustment is through changing the compensating
jet (the Russians call it a suction jet).
d.. This is available in 0.05mm changes, from 0.9mm to 2.0mm.
e.. At high power settings excessive cylinder head temperatures is usually indicative
of a weak mixture, and therefore a need for a smaller compensating jet
(smaller because it is compensating and therefore gives richer mixture).
f.. The compensating jets are very easy to change - a couple of minutes once
you have access to the carburettor.
g.. He is correct that 1150mm of mercury equals 15 inches of boost - ie total
intake pressure would be +15, given atmospheric is 30.
h.. There are no performance tables in the form of graphs for the 400-hp and
450-hp, but out of interest I am attaching the actual power for the last 450-hp
M14R we delivered.
Richard Goode
Richard Goode Aerobatics
Newport House
Almeley
Herefordshire
HR3 6LL
United Kingdom
Tel: 44 (0) 1544 322200
Mob: 44 (0) 7768 610389
Fax: 44 (0) 1544 322208
www.russianaeros.com
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Message 2
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| Subject: | Re: MAP and RPM (was: range) |
--> Yak-List message posted by: Sam Sax <cd001633@mindspring.com>
>Death Valley will get you -200 MSL. Also there is a valley below sea level in
Israel whose name escapes me at >the moment.
That are in Israel is the Dead Sea basin (where the Jordan river end). Elevation
-1200 feet.
Felt real wierd flying a jet at 400 kt while the pressure altimeter indicating
-800'... Engine seemed to like it though.
Sam
Message 3
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"Yak USA List" <yak-list@matronics.com>
| Subject: | Re: In reply to Bill Halverson |
--> Yak-List message posted by: Bill Halverson <william@netpros.net>
Thank your George for the good info!
Best regards,
Bill Halverson
At 08:43 AM 10/21/2003, Richard Goode wrote:
>In reply to Bill Halverson:
>The AK-14P carburettor is extremely complicated, but correct adjustment
>can make a huge difference to the way the engine runs.
Message 4
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"Yak USA List" <yak-list@matronics.com>
| Subject: | Re: In reply to Bill Halverson |
--> Yak-List message posted by: Bill Halverson <william@netpros.net>
Boy I am sorry .. not awake yet ...
Thank you Richard!!!!
Bill
At 08:43 AM 10/21/2003, Richard Goode wrote:
>In reply to Bill Halverson:
>The AK-14P carburettor is extremely complicated, but correct adjustment
>can make a huge difference to the way the engine runs.
William Halverson, Director
Pacific Center for Telehealth
www.pacthealth.org
Message 5
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--> Yak-List message posted by: "Mark Jefferies YAK UK Ltd" <mark@yakuk.com>
Aubrey.
Pls also note that over tightening the back nut on the PRV will stretch the body
making the internal smaller diameter and causing the piston to stick, if this
happens you will need to polish the brass piston.
hope this help reduce the problem for others. Applies to the YAK series, not sure
about the CJ.
Mark j.
--> Yak-List message posted by: Aubrey Price <aprice@vartec.net>
I just got off the phone will Jill and Carl. Carl suggested I put this out
for everyone to think about.
When we bought our YAK52 aircraft, I noticed that the reserve air pressure
was at about 75 ATM. I lowered the pressure and ask why. The pilot told me
that he had seen the pressure go up to 80ATM at times. This didn't make me
feel great.
Message 6
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| Subject: | Operating Restrictions - Help! |
--> Yak-List message posted by: cpayne@joimail.com
I'm meeting with a FSDO rep tomorrow at my hanger. He wants
to see the airplane and logbooks and has a new set of
operating restrictions. "Not much added", he says. "Just
updated". Guess I'll find out.
I bounced the idea of ID'ng the Home Airport by the phrase
"As listed in the owner's program letter". He may lean that
way IF I can point out Where (FSDO) and who has had such
wording issued to them. ANYONE???
Craig Payne
Message 7
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| Subject: | In reply to Bill Halverson Richard Goode |
--> Yak-List message posted by: "Gus Fraser" <fraseg@comcast.net>
Richard,
Could you explain how increasing the MP to 1150mm gives 450 HP?
I am a simple man and know that for a 40 hp increase (360-400hp) MP goes
from 870mm to 1040 mm and you are saying for another 50 hp (400-450hp) you
only need an extra 110 mm i.e. 1040 to 1150mm as opposed to 170mm to get 40
hp. It appears to me that the new engine is producing 430 hp, based upon
your figures below this seams to be the case. I assume the "new 450 hp"
statement is a rounding error?
>In passing, the new 450-hp M14R is boosting at 1150mm (as opposed to about
>870mm for the 360-hp and 1040mm for the 400-hp). This equates to just over
>45inches of boost.
Further its impossible to turn a supercharger faster and yet use the same
fuel, yes I agree you can lean the mixture by changing the jets but its my
view the mixture should be enriched slightly to add cooling to the engine as
its well know the M14PF runs hot and in some cases runs over the OEM oil
temp specifications.
>Vedeneyev, the designer, says that at the same power settings, fuel
>consumption is the same. Remember that fuel consumption can vary
>considerably from engine to engine by virtue of changing the air
>compensating jet.
I am just a poor physics major maybe I missed something :)
Gus
Message 8
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| Subject: | Re: Operating Restrictions - Help! |
--> Yak-List message posted by: "A. Dennis Savarese" <adsavar@gte.net>
The Detroit FSDO has issued numerous OL's with "Operational Program Letters"
which state the home base airport. I will email you off-list a copy of one
I use for Experimental Exhibition.
Dennis
----- Original Message -----
From: <cpayne@joimail.com>
Subject: Yak-List: Operating Restrictions - Help!
> --> Yak-List message posted by: cpayne@joimail.com
>
> I'm meeting with a FSDO rep tomorrow at my hanger. He wants
> to see the airplane and logbooks and has a new set of
> operating restrictions. "Not much added", he says. "Just
> updated". Guess I'll find out.
>
> I bounced the idea of ID'ng the Home Airport by the phrase
> "As listed in the owner's program letter". He may lean that
> way IF I can point out Where (FSDO) and who has had such
> wording issued to them. ANYONE???
>
> Craig Payne
>
>
Message 9
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| Subject: | Re: Request from the Smoking Section..... |
--> Yak-List message posted by: "Dee Grimm" <deegrimm@cox.net>
Hi Jeff,
The gang in Phoenix is using Diala oil. It seems to work fine. It does,
however leave a mess on the bottom of my airplane. One of our local show
pilots says that the Diala oil can be mixed about 50% with Jet fuel and
still work fine. We are paying about $204.05 per 55 gallon barrell for the
oil. We purchased it from one of the local oil dealers.
Regards, Dee
----- Original Message -----
From: "Jeff Linebaugh" <jefflinebaugh@earthlink.net>
Subject: Yak-List: Request from the Smoking Section.....
> --> Yak-List message posted by: "Jeff Linebaugh"
<jefflinebaugh@earthlink.net>
>
> After a surprise present from my wife, I am now among the "smoking" crowd
> with our CJ. (She pulled it off in a neat way too...while we were away,
she
> had our mechanic install, and test the system....when we came home, we
were
> welcomed by a smoking flyover!)
>
> So, a couple of questions for you "smokers".... I have heard a few
options
> for what to use for smoke oil....I am looking for opinions and sources for
> smoke oil. I'd appreciate your help!
>
> Thanks,
>
> Jeff Linebaugh
> jefflinebaugh@earthlink.net
> Memphis, TN
>
>
Message 10
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| Subject: | Re: Request from the Smoking Section..... |
--> Yak-List message posted by: cjpilot710@aol.com
The best smoke oil I've seen was Corbis B. I understand it is a mold release
oil used a lot in concrete work and has a lot of paraffin it. Not to cheap.
I've also use 10w jet engine oil from the test cell where my brother works.
It puts out smoke OK but its really cheap. Like "free". After jet engines
are run in the test cells, the oil is always drained out and NEVER used again.
Most outfit hire companies to depose of it for them. My brother brings me 20
gals every now and than which last quite a while for what I do. Maybe you
check around Memphis airport there for a sorce.
Jim Goolsby
"They that can give up essential liberty to obtain a little safety,
deserve neither liberty nor safety"
Benjamin Franklin 1759
"With my shield, or on it"
Trojan Warriors BC
"The reason older men are like fine wine. When young, they are like grapes
until some woman stomps all over them."
Unknown older man.
Message 11
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| Subject: | Re: MAP and RPM (was: range) |
--> Yak-List message posted by: "Dee Grimm" <deegrimm@cox.net>
The 4360's as used on the C-97 had turbo superchargers providing boost above
the engine driven internal compressor and there was no interface between the
MAP and the RPM. It was all manually controlled by the flight engineer
utilizing the throttle, a waste gate control and the torque gage (indicating
the BMEP.)
Regards, Dee
Regards, Dee
----- Original Message -----
From: "Walt Lannon" <lannon@look.ca>
Subject: Re: Yak-List: MAP and RPM (was: range)
> --> Yak-List message posted by: "Walt Lannon" <lannon@look.ca>
>
>
> ----- Original Message -----
> From: "Brian Lloyd" <brian@lloyd.com>
> To: <yak-list@matronics.com>
> Subject: Yak-List: MAP and RPM (was: range)
>
>
> > --> Yak-List message posted by: Brian Lloyd <brian@lloyd.com>
> >
> > Walt Lannon wrote:
> >
> > > A supercharger is a device designed to increase engine manifold
> > > pressure and therefore increase output horsepower. The term generally
> > > refers to an internal engine driven centrifugal blower. A
> > > turbocharger is an externally driven supercharger, driven by exhaust
> > > gases. It could be driven by some other power source and have another
> > > name but it would still be a supercharger.
> >
> > Yes, I know. I will take care to be even more specific, exact, and
> detailed in my next post.
>
> I will try to do that as well but I usually screw it up.
>
> > BTW, you can also have a vane-type "Roots" supercharger as well. I
don't
> recall if I have seen any of those on aircraft engines but it is not
beyond
> the realm of reason.
>
> I think the Roots blower was used on some early British engines.
>
> > > All supercharged engines regardless of boost source are technically
> > > "altitude" engines and have a critical altitude. In the case of the
> > > Huosai, M14P, AI14R, etc. the critical altitude happens to be sea
> > > level so it becomes a moot point unless you were operating from below
> > > that level.
> >
> > It is still a moot point because the specification for maximum MAP is
> ambient pressure plus 85mm-Hg so you can still use full boost below sea
> level.
>
> Yep! I don't know where you would have to go to get that low an altitude.
>
> > > normally aspirated engine has no critical altitude; ie: full throttle
> > > can be applied at any altitude assuming RPM and fuel mixture are
> > > correct.
> > >
> > > The critical altitude may be defined as the altitude at which full
> > > throttle operation will not exceed the engines design rated (ie:
> > > maximum continuous) power.
> >
> > I think I would define it slightly differently. Critical altitude is
the
> altitude that maximum available boost does not exceed maximum specified
MAP
> for conditions. Critical altitude may be different for TO, METO, and max
> continuous power. For some engines it will also change with fuel octane
> ratings and RPM.
>
> I think I have pretty closely paraphrased the P&W definition. METO and
max.
> continuous are usually the same. Take-off power is a specific increase
above
> METO and is time limited (for the 1340 it's 600 HP @ 2250 and 36" for a
max.
> of 5 mins.). These specs. (TO, METO, MAX. CONT.) are specified by the
> manufacturer for a specific fuel grade. They have, I believe, been
> down-graded in some of the larger engines for lower octane fuels. The R985
> and R1340 were recertified at the same levels for 80/87 when 91/98 was
> discontinued.
>
> > > All other supercharged engines that I am aware of have a critical
> > > altitude at some point above sea level. This is true also of a waste
> > > gated system, the pilot may be able to apply full throttle for
> > > take-off and climb with the waste gate automatically controlling the
> > > MAP. Upon reaching the critical altitude the waste gate will be
> > > closed.
> >
> > Correct.
> >
> > > For example the P&W R1340 rated at 550 HP max. cont. at 32.5 in. and
> > > 2200 RPM can maintain that power to 5500 ft. in standard air with the
> > > 10:1 blower. The critical altitude of the 12:1 blower model is
> > > approx. 7000 ft. Above these points the MAP will decrease like a
> > > normally aspirated engine.
> >
> > Well actually, if you leave the throttle alone, the MAP will decrease
with
> altitude anyway. But you are allowed to continue opening the throttle in
> order to maintain that 32.5 in-Hg MAP since the "blower" has excess boost.
>
> Agreed and I rarely ever use rated (max.climb) power for more than a few
> minutes - burns too much gas!
>
> > > This is a simple single stage, single speed blower. There are much
> > > more complex designs, some with turbochargers as well that can
> > > increase the crit.alt. dramatically.
> >
> > Yes.
> >
> > > The suggestion that "one should run with the throttle wide and vary
> > > power with the prop control" is not good advice.
> >
> > Yes, it is, depending on the engine. For the M14 and Huosai, it should
> work just fine without causing any damage to the engine. For instance,
with
> the Huosai engine I have found no documented minimum RPM figures for a
given
> MAP. The only limit I can see is that you may operate at full throttle
and
> 2250 RPM for up to 1 hour with a 5 minute break after that. If you reduce
> the MAP to 28 in-Hg you may run up to 2250 RPM for a long as you want.
> Since BMEP decreases with decreasing MAP, and since MAP decreases as RPM
> decreases, I can see nothing that contraindicates full throttle operation
> with reduced RPM.
>
> > In larger radial engines there are maximum MAP values for differing RPM.
> The pilot must ensure that the MAP does not exceed specifications for a
> given RPM and fuel type, but even with that there is latitude to make RPM
> reductions without making MAP reductions. (Maximum MAP for big radials is
> also different depending on whether you are running 100/130 octane or
> 115/140 octane. They may also have torque limitations as well.)
> >
> > I was making the point that people who worry about pulling the prop back
> without reducing the throttle first are probably avoiding a perfectly
valid
> and safe mode of operation.
>
> Interesting concept, reducing RPM with a fixed throttle opening and a MAP
> above ambient should, as you suggest, reduce the MAP. But, having,
> figuratively, grown up with radial engines the rule is etched on my
brain -
> Pitch down (inc. RPM) then Power up and Power down then Pitch up (dec.
RPM).
> Strangely enough P&W seem to agree with this rule. This is probably due
(in
> the open throttle, RPM down case) to an increasing propellor load that
could
> exceed the power reduction of reduced MAP.
> The CJ manual does give some specific power specs. other than TO and
rated.
> 65% @ 1950 & 660(26") and 50% @ 1790 & 600(23.6") for the Huosai 6A. I
think
> if one tries to maintain close to that spread there should be no problem.
> They run out of puff so quickly with altitude that overboosting is
unlikely
> but overstressing of pistons and rods could be a concern with low MAP and
> high RPM.
>
> > > The fact that Bud Granley was able to reduce power in the Sea Fury in
> > > this manner in no way recommends this procedure for the engines we
> > > are operating.
> >
> > The point I was making is that a radical RPM reduction will also bring a
> radical reduction in MAP. As long as one does not exceed the maximum MAP
> for a given RPM setting, one can continue to reduce RPM without reducing
> MAP.
>
> Do you mean " without increasing MAP" ?
>
> > > It is entirely possible that the R4360 in this case is
> > > equipped with automatic devices sensing MAP and RPM and controlling a
> > > waste gate.
> >
> > The standard R4360 does not have an exhaust-gas-driven turbosupercharger
> (since we are getting picky about names). There may have been some
> installations with one fitted but I am not aware of any modified Sea Furys
> with such. Therefore, there is no waste gate, a waste gate being a device
> that controls exhaust gas bypass around the turbine in an
exhaust-gas-driven
> turbosupercharger. I think you may be thinking of what is commonly called
a
> overpressure limit valve that opens to reduce excessive induction system
> pressure.
> >
> > No, in this case reducing engine RPM with the prop control reduces the
RPM
> of the centrifugal compressor stage ("blower") since the compressor is
> directly geared to the crankshaft. The gear ratio is 6:1 in the R4360 so
> the "blower" rotates at six times the crank RPM. Reducing crank RPM
reduces
> "blower" RPM and reduces available boost substantially.
> >
> > > You may get away with that practice for a little while with the
> > > Huosai, M14P etc. but you will eventually fail the engine. With a
> > > truly supercharged engine you could destroy it in a matter of
> > > minutes.
> >
> > Again, I believe you might not be correct in all cases. In all engines
> you must adhere to the operating limitations but within that range you are
> free to use various combinations of MAP and RPM. The point I made and
still
> make is that, with the Huosai and Vendeneyev engines, you have tremendous
> latitude to make RPM reductions without making a corresponding MAP
> reduction. Larger radial engines may not have the same latitude due to
the
> greater available boost, increased compression, or whatever. But even
there
> it was normal to operate at very low RPMs with relatively high MAP.
>
> I am never correct in all cases! Using the term waste gate for the 4360
was
> a brain fart. I was thinking of some type of MAP relief valve though I
have
> no idea if there is such a valve. Now that you have forced me to really
> think (which gives me a headache) about all this I would suggest that the
> negative result of the open throttle, reduce RPM approach is increased
> propellor loading that could result in internal engine damage.
>
> In Bud,s case with the Sea Fury this was an emergency situation and that
> action had the desired result - a safe landing.
>
> > > Just as a matter of interest (and maybe generate a little
> > > controversy) the blower is the reason the T6/Harvard runs away from
> > > the CJ6 (Huosai or M14) above 6000 ft or so.
> >
> > The supercharger in the R1340 is capable of overboosting the engine
> (exceeding maximum allowable MAP) thus leading to a critical altitude
above
> which the engine cannot maintain rated power. The Huosai and Vendeneyev
> engines are already running with maximum boost at sea level so they are
> losing power already as they climb. Therefore I suspect you very well may
> be right.
>
> Yeah, but it hurts at the fuel pump!
>
> Walt
> > --
> >
> > Brian Lloyd 6501 Red Hook Plaza, Suite 201
> > brian@lloyd.com St. Thomas, VI 00802
> > +1.340.998.9447 - voice +1.360.838.9669 - fax
> > GMT-4
> >
> >
>
>
Message 12
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| Subject: | Re: MAP and RPM (was: range) |
--> Yak-List message posted by: cjpilot710@aol.com
Something to note.
When we fly the B-24 and B-17 at the Collings Foundation, we're very careful
about "back loading" the engines. We treat them tenderly. At $40,000 to
overhaul either the P&W 1830 (B-24) or the W-1820 (B-17) times 4, well we babied
them big time. Both engines are have super chargers and turbo chargers (via
waste gate). The waste gates are disconnected on the B-17 but not the P&W-1830
on the B-24. In anycase we never pull more than 45"mp. We're not carrying
8,000 (B-24) or 4,000 (B-17) pounds of bombs either. Just about every take-off
we use 2,700 rpm and 40" to 42"mp (= 600 gph). Our normal cruise is 2,000 rpm
and 30" which give both aircraft about 200 gph in auto lean.
We make our approaches at 2,000 rpm and NEVER LESS than 22"mp. We are trying
to keep the prop from driving the engine. These engines have no oil l
ubrication holes on the 'anti-thrust side' of the master-rod. It does not take
many
hours to ruin these engines, if you push the rpms up on the downwind while
making your approach. The Wrights stand up a little better simply because they
have a little more metal on the mater-rod.
Rule of thumb -' Always keep aleast 1 inch over rpm'. i.e. 2,200rpm mp> 23"
Jim Goolsby
"They that can give up essential liberty to obtain a little safety,
deserve neither liberty nor safety"
Benjamin Franklin 1759
"With my shield, or on it"
Trojan Warriors BC
"The reason older men are like fine wine. When young, they are like grapes
until some woman stomps all over them."
Unknown older man.
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