Today's Message Index:
----------------------
1. 01:35 AM - Another RV-10 flying! (with some performance questions) (Dan Charrois)
2. 05:08 AM - Re: Another RV-10 flying! (with some performance questions) (Jesse Saint)
3. 06:01 AM - Re: Another RV-10 flying! (with some performance questions) (Tim Olson)
4. 06:37 AM - Re: Another RV-10 flying! (with some performance questions) (Kelly McMullen)
5. 11:35 AM - Re: Elevator Push Rod Issue (Werner Schneider)
6. 01:20 PM - Re: Elevator Push Rod Issue (william donahoe)
7. 07:10 PM - Re: Another RV-10 flying! (with some performance questions) (Tim Lewis)
Message 1
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| Subject: | Another RV-10 flying! (with some performance questions) |
Hi everyone.
I'm happy to say that after 11+ years of work, my RV-10 is finally in the air.
As a testament to Van's incredible design (both in terms of the airframe performance
and reliability, and perhaps equally importantly, in producing a kit that
newcomers to the idea of homebuilding can build safely) , the first flight
(and subsequent ones) have been pretty much uneventful. Everything "just works"
- the plane handles like a dream and I'm looking forward to spending thousands
of hours flying it. Still a ways to go yet - I'm currently at 9 hours of
flight time in it :-)
But as nice as the plane seems to be, I'm in the phase right now of analyzing the
heck out of everything to make sure it's operating as it should (fortunately,
I have some AFS EFISes in there that log data for me to go over afterwards).
And though the plane is operating 99% as well as I hoped for, there are a couple
of things not operating quite as I expected - I'm after other people's advice
to see if they've experienced something similar. Any help or insight anyone
can give on any of these issues would be greatly appreciated!
My plane is a pretty standard build with a factory-new Lycoming IO-540 D4A5 and
3-bladed MT prop.
1. Fuel pressure drop climbing to higher altitudes: Today, I did an "informal"
climb at 110 KIAS and 2500 RPM/full throttle/full rich to 10000' to see how
it would handle it. At around 3200' MSL, I see a fuel pressure of about 21psi
with the engine pump (boost pump off). But in the climb, the fuel pressure drops
significantly. At 5000', it's at 18psi, at 7000' it was about 16psi, then
it started dropping faster. At 8000' it was down to 13psi and by 8700' had
dropped down to 11psi. I turned the boost pump back on and it promptly shot back
up to 20psi, so I continued the climb to 10000' and then made my way back
down. By the time I got back down to 4300' I turned the boost pump off and the
engine pump maintained pressure at 22psi. I never did take the chance to level
out and test pressure further - without knowing if it was a significant cause
for concern, I got back down to the lower altitudes instead. I haven't seen
any significant pressure fluctuations in flying around under 5000'.
According to the Lycoming manual, the fuel pressure for the IO-540-D4A5 at the
fuel injector is supposed to be between 14 and 45 psi. This is where the Van's
stock fuel pressure sensor is measuring, isn't it? Though I've seen at least
two other pilot's RV-10 POHs that use numbers for the acceptable pressure to
be what Lycoming quotes as that for the inlet to the fuel pump of -2 to 35 psi,
so it's got me wondering if I'm misinterpreting either the Lycoming documentation
or the fuel plumbing. So the question I have - is that low fuel pressure
the cause for concern I think it is? If so, what might be causing it, and
how would I fix it? Or is it normal? What do other people see in climb to 10000'?
Though I can use the boost pump for climbs to higher altitudes (and I've
heard of some certified aircraft that suggest it), it doesn't strike me as an
appropriate measure if the boost pump were to fail.
2. Rate of climb at high altitudes: I haven't constructed the wheel pants yet,
so I know performance will improve when they're done. At low altitudes I certainly
can't complain about rate of climb - with 450 pounds of fuel and me, I
did a short field takeoff today climbing out at about 85 knots and saw a 2150
fpm climb rate. But when I got up near the 10000' point, at 110 KIAS, I was
only getting around 500 fpm. I haven't done proper climb charts yet, but since
I've heard of lots of people cruising in the RV-10 at 15000'-17000', how are
they getting up there? My climb was at full rich, as I've been taught to do
in lower performing planes - is it standard practice to lean out the mixture in
climbs up at that altitude for more power? Or perhaps a slower climb speed/steeper
angle than my 110 KIAS?
3. Performance in general: I did some airspeed indicator calibrations today at
different power settings at 3200', and ended up with the following true airspeeds:
25"/2500RPM: 150 knots, 24"/2400 RPM: 147 knots, 23"/2300 RPM: 141 knots,
21"/2300 RPM: 134 knots, 18"/2300 RPM: 118 knots, 16"/2200 RPM: 103 knots.
These numbers are without wheel pants, but with that in mind, do they seem reasonable?
Vans' web site suggests cruise at 171 knots at 75% power at 8000'.
I know that claims should be taken with a grain of salt, and I didn't run these
tests at 8000', but if my calculations are correct, at 25"/2500 RPM I should
have been producing about 80% power. Is it expected that the wheel pants and/or
a higher altitude are going to make a significant enough improvement to get
closer to Van's numbers?
4. CHT temps: To break in the engine, I've been running it pretty hard - usually
around 25"/2500 most of the time (with some cycling to 25"/2600 or down to
24"/2400 to avoid building a ridge in the cylinder). In cruise with those power
settings, my cylinders 3 and 4 run comparatively cool at around 375F. Cylinders
2, 5, and 6 are about 410F, but cylinder 1 is a bit of an anomaly. Usually
it's the hottest of all, getting up to around 440 (5 degrees hotter than
Lycoming's recommendation for maximum service life), though there have been a
few times where it's dropped rather abruptly by 50-60 degrees (for no apparent
reason I can see), making it surprisingly suddenly the coolest cylinder. But
it doesn't stay there - after awhile, it climbs back up to step in line with
what cylinders 2, 5, and 6 are doing... but usually stays 20-30 degrees hotter
than the rest. Outside temperatures have been around 30-40 Fahrenheit during
the flights so far.
Of course, at lower power settings, the CHTs all drop down to well under 400.
And all power settings, the engine operation has been very smooth - no roughness
at all.
I can reduce the height of the dam in front of cylinder 1, and I've heard of lots
of people having to do that. But especially with the strange temperature fluctuations
I'm still not sure if it's fully broken in yet, so I've been holding
off until things settle. Has anyone else noticed a hot cylinder 1, and if
so, how much of the front dam did you remove to cool it down? The good thing
is my centre two cylinders seem plenty cool so I should be able to sacrifice some
of their airflow to get #1 down.
5. Break in: I've flown the engine pretty hard now for 9 hours, but haven't seen
any dramatic sign of CHTs reducing as is supposed to happen with a break in
(with that said, the engine was run in at Lycoming for about an hour, and about
45 minutes on the ground under supervision of an aircraft engine shop for
further break in before first flight). Other indications like "until the oil
consumption has stabilized" haven't helped either - I put in about 3/4 quart of
oil at about the 6 hour mark, but that's been it.... so far, it hasn't used
excessive oil, and as I've only added oil once, I'm unsure of how to even define
"stabilized". Now that I'm at the 9 hour mark for flight (11 hours on the
engine overall), should I conclude that the engine is probably broken in about
as good as it's going to get, or should I still be holding out for a noticeable
drop in CHTs?
Sorry for the long email! But if anyone has any suggestions, advice, or comments
on any of these or other issues, I'd certainly appreciate hearing from you!
I'm looking forward to meeting with some of you at fly ins, as soon as I finish
flying off the 25 hours I need to do first!
Dan
---
Dan Charrois
President, Syzygy Research & Technology
Phone: 780-961-2213
Message 2
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| Subject: | Re: Another RV-10 flying! (with some performance questions) |
1. A lot of the RV-10's do this. I know people who have changed out their engine
driven pumps thinking they were going bad and nothing changed. The main thing
to monitor is if your engine starts leaning out or stumbling because of it.
If everything is smooth, then it's not a problem. The pressure at the inlet to
the pump has a much different range because it can be sucking the fuel from a
substantially lower point (the "-2") or it can be pressurized by the boost pump
(the "35"). If stock, you are measuring at the pump outlet. Keep your eyes
on it and you should be fine, but it doesn't hurt to run the boost pump for peace
of mind.
2. You should absolutely lean out the mixture as you climb. I start leaning by
1,500' usually. I lean the EGT's out to about 100-150 degrees ROP in the climb.
You can find this number by seeing what your EGT's peak at. To do this, run
20" and 2400 rpm at 3,000' and lean until they peak. I see most peak at 1,425-1,450.
If so, I climb with the hottest cylinder at 1,300-1,325, and keep leaning
as I climb to keep it there. I run a little more rich if I need to for CHT's,
but I never run WOT much above the pattern. This will make a huge difference
in your power, especially as you approach 10,000'. I suspect that 1 and 2 are
somewhat related. If you start to lean, your fuel flow will decrease as you
climb, and your fuel pump will be able to maintain a higher pressure.
3. Some planes are faster than others and some are slower, but I have only seen
a total speed fluctuation of less than 10 ktas. The MT prop is slightly slower
than the Van's-used Hartzell. Some say it's the same, and others say it's 8
knots slower. It's somewhere in that range. The takeoff and climb is supposed
to be better, which I suspect will prove true once you start leaning. The wheel
pants and gear leg fairings, in my experience, add about 17 kts. That should
get you fairly close to the Van's numbers. I suspect you will I prove speed by
leaning. Run the speed tests at 6,000-8,000 density altitude. In my experience
the absolute fastest is at about 6,500 density altitude, wide open throttle,
matching prop rpm and about 15-16 gph fuel flow. Most RV-10's will get 174-183
ktas in this test.
4. I suspect you have the air dam in front of Cylinders 1 and 2. Remove the dam
from Cylinder 1 to see if that helps. I usually end up leaving those air dams
out completely on both 1 and 2. I suspect it will. Then, increase your climb
airspeed to lower those temps. Temps will come down as the engine breaks in, but
those number are hotter than I like to see. Try to keep them below 400 if possible,
and certainly below 420. The fluctuation seems to me to be more of a
gauge issue than the cylinder. I assume these temps are all in climb. Take another
look through your baffles and seal any spots where air can get to the lower
cowl without going through the cylinder fins. These engines usually require
at least half a caulk tube of RTV to seal well.
5. You may still get a decent drop in CHT's, but you may already be broken in most
of the way. How high are you keeping your oil? I usually add 8 quarts at a
change including the filter, and add a quart when it gets to 6.5. I've seen these
engines settle in at 5 hrs/quart to 20+ hrs/quart. It sounds like you are
at about 8-10 now. See if that drops.
Jesse Saint
Saint Aviation, Inc.
352-427-0285
jesse@saintaviation.com
Sent from my iPad
> On Jan 29, 2017, at 4:34 AM, Dan Charrois <dan@syz.com> wrote:
>
>
> Hi everyone.
>
> I'm happy to say that after 11+ years of work, my RV-10 is finally in the air.
As a testament to Van's incredible design (both in terms of the airframe performance
and reliability, and perhaps equally importantly, in producing a kit
that newcomers to the idea of homebuilding can build safely) , the first flight
(and subsequent ones) have been pretty much uneventful. Everything "just works"
- the plane handles like a dream and I'm looking forward to spending thousands
of hours flying it. Still a ways to go yet - I'm currently at 9 hours
of flight time in it :-)
>
> But as nice as the plane seems to be, I'm in the phase right now of analyzing
the heck out of everything to make sure it's operating as it should (fortunately,
I have some AFS EFISes in there that log data for me to go over afterwards).
And though the plane is operating 99% as well as I hoped for, there are a
couple of things not operating quite as I expected - I'm after other people's
advice to see if they've experienced something similar. Any help or insight
anyone can give on any of these issues would be greatly appreciated!
>
> My plane is a pretty standard build with a factory-new Lycoming IO-540 D4A5 and
3-bladed MT prop.
>
>
>
> 1. Fuel pressure drop climbing to higher altitudes: Today, I did an "informal"
climb at 110 KIAS and 2500 RPM/full throttle/full rich to 10000' to see how
it would handle it. At around 3200' MSL, I see a fuel pressure of about 21psi
with the engine pump (boost pump off). But in the climb, the fuel pressure
drops significantly. At 5000', it's at 18psi, at 7000' it was about 16psi, then
it started dropping faster. At 8000' it was down to 13psi and by 8700' had
dropped down to 11psi. I turned the boost pump back on and it promptly shot
back up to 20psi, so I continued the climb to 10000' and then made my way back
down. By the time I got back down to 4300' I turned the boost pump off and
the engine pump maintained pressure at 22psi. I never did take the chance to
level out and test pressure further - without knowing if it was a significant
cause for concern, I got back down to the lower altitudes instead. I haven't
seen any significant pressure fluctuations in flying a!
> round under 5000'.
>
> According to the Lycoming manual, the fuel pressure for the IO-540-D4A5 at the
fuel injector is supposed to be between 14 and 45 psi. This is where the Van's
stock fuel pressure sensor is measuring, isn't it? Though I've seen at least
two other pilot's RV-10 POHs that use numbers for the acceptable pressure
to be what Lycoming quotes as that for the inlet to the fuel pump of -2 to 35
psi, so it's got me wondering if I'm misinterpreting either the Lycoming documentation
or the fuel plumbing. So the question I have - is that low fuel pressure
the cause for concern I think it is? If so, what might be causing it, and
how would I fix it? Or is it normal? What do other people see in climb to 10000'?
Though I can use the boost pump for climbs to higher altitudes (and I've
heard of some certified aircraft that suggest it), it doesn't strike me as
an appropriate measure if the boost pump were to fail.
>
>
>
> 2. Rate of climb at high altitudes: I haven't constructed the wheel pants yet,
so I know performance will improve when they're done. At low altitudes I
certainly can't complain about rate of climb - with 450 pounds of fuel and me,
I did a short field takeoff today climbing out at about 85 knots and saw a 2150
fpm climb rate. But when I got up near the 10000' point, at 110 KIAS, I was
only getting around 500 fpm. I haven't done proper climb charts yet, but since
I've heard of lots of people cruising in the RV-10 at 15000'-17000', how are
they getting up there? My climb was at full rich, as I've been taught to do
in lower performing planes - is it standard practice to lean out the mixture
in climbs up at that altitude for more power? Or perhaps a slower climb speed/steeper
angle than my 110 KIAS?
>
>
>
> 3. Performance in general: I did some airspeed indicator calibrations today
at different power settings at 3200', and ended up with the following true airspeeds:
25"/2500RPM: 150 knots, 24"/2400 RPM: 147 knots, 23"/2300 RPM: 141 knots,
21"/2300 RPM: 134 knots, 18"/2300 RPM: 118 knots, 16"/2200 RPM: 103 knots.
These numbers are without wheel pants, but with that in mind, do they seem reasonable?
Vans' web site suggests cruise at 171 knots at 75% power at 8000'.
I know that claims should be taken with a grain of salt, and I didn't run these
tests at 8000', but if my calculations are correct, at 25"/2500 RPM I should
have been producing about 80% power. Is it expected that the wheel pants and/or
a higher altitude are going to make a significant enough improvement to
get closer to Van's numbers?
>
>
>
> 4. CHT temps: To break in the engine, I've been running it pretty hard - usually
around 25"/2500 most of the time (with some cycling to 25"/2600 or down
to 24"/2400 to avoid building a ridge in the cylinder). In cruise with those
power settings, my cylinders 3 and 4 run comparatively cool at around 375F. Cylinders
2, 5, and 6 are about 410F, but cylinder 1 is a bit of an anomaly. Usually
it's the hottest of all, getting up to around 440 (5 degrees hotter than
Lycoming's recommendation for maximum service life), though there have been
a few times where it's dropped rather abruptly by 50-60 degrees (for no apparent
reason I can see), making it surprisingly suddenly the coolest cylinder. But
it doesn't stay there - after awhile, it climbs back up to step in line with
what cylinders 2, 5, and 6 are doing... but usually stays 20-30 degrees hotter
than the rest. Outside temperatures have been around 30-40 Fahrenheit during
the flights so far.
>
> Of course, at lower power settings, the CHTs all drop down to well under 400.
And all power settings, the engine operation has been very smooth - no roughness
at all.
>
> I can reduce the height of the dam in front of cylinder 1, and I've heard of
lots of people having to do that. But especially with the strange temperature
fluctuations I'm still not sure if it's fully broken in yet, so I've been holding
off until things settle. Has anyone else noticed a hot cylinder 1, and if
so, how much of the front dam did you remove to cool it down? The good thing
is my centre two cylinders seem plenty cool so I should be able to sacrifice
some of their airflow to get #1 down.
>
>
>
> 5. Break in: I've flown the engine pretty hard now for 9 hours, but haven't
seen any dramatic sign of CHTs reducing as is supposed to happen with a break
in (with that said, the engine was run in at Lycoming for about an hour, and
about 45 minutes on the ground under supervision of an aircraft engine shop for
further break in before first flight). Other indications like "until the oil
consumption has stabilized" haven't helped either - I put in about 3/4 quart
of oil at about the 6 hour mark, but that's been it.... so far, it hasn't used
excessive oil, and as I've only added oil once, I'm unsure of how to even define
"stabilized". Now that I'm at the 9 hour mark for flight (11 hours on the
engine overall), should I conclude that the engine is probably broken in about
as good as it's going to get, or should I still be holding out for a noticeable
drop in CHTs?
>
>
>
> Sorry for the long email! But if anyone has any suggestions, advice, or comments
on any of these or other issues, I'd certainly appreciate hearing from you!
>
> I'm looking forward to meeting with some of you at fly ins, as soon as I finish
flying off the 25 hours I need to do first!
>
> Dan
> ---
> Dan Charrois
> President, Syzygy Research & Technology
> Phone: 780-961-2213
>
>
>
>
>
Message 3
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| Subject: | Re: Another RV-10 flying! (with some performance questions) |
Dan,
A big congrats. I'd write a long reply but Jesse replied most of what I would
have said, so take his advice. On the fuel pressure issue don't sweat it just
use the boost pump. I did buy a fuel pump cooling shroud but haven't installed
it. I suspect that if I did install it , it would help then fuel pressure
at altitude.
Also, i did a write up late my ago about cutting CHTs. Read that and just basically
check your baffling, cooling find, and seal any leaks around your cylinders.
Some people place a washer spacer behind the back cylinders as well. I
would halt your climb if you get over 410 degrees or even 400. Certainly don't
let it hit 440 like you mentioned. Don't let the oil temp get past 240 either....or
I would prefer 225-230. Keeping the oil temp under 200-210 and CHTs
below 400 will be beneficial to long engine life. Climb at higher airspeeds.
Lean for climb. My person rule of thumb is to start leaning at around 5000' and
lean anytime your EGTs are below 1225. Just lean them until the hottest EGTs
are about 1225-1250, and keep them there on the way up.
Performance wise it's not even worth doing the numbers to compare to others until
you have the wheel and leg fairings done. It's an extreme difference.
For the air dams, if you are flying with them full height just chop them down to
about half. Many people remove them but I'd say start with 1/2. I don't think
most anyone will have things be as cool
As they want if they leave them full height. The Rv14 Van's did smarter and they
are easily removable or replaceable.
Also for climb rate, leaning will help but once you get over about 12-13,000' you're
going to see that climb rate get slower. It is impractical for most people
to fly the RV10 over 16,000-17,000' unless they are carrying no load. I have
been full gross to 16,500 but it climbs so slowly that it's not worth it.
Plan your trips to stay below 14,500 and you will be fine with the occasional
excursion over 16,000.
Enjoy the plane and treat it right and it will return the favor.
Tim
> On Jan 29, 2017, at 3:34 AM, Dan Charrois <dan@syz.com> wrote:
>
>
> Hi everyone.
>
> I'm happy to say that after 11+ years of work, my RV-10 is finally in the air.
As a testament to Van's incredible design (both in terms of the airframe performance
and reliability, and perhaps equally importantly, in producing a kit
that newcomers to the idea of homebuilding can build safely) , the first flight
(and subsequent ones) have been pretty much uneventful. Everything "just works"
- the plane handles like a dream and I'm looking forward to spending thousands
of hours flying it. Still a ways to go yet - I'm currently at 9 hours
of flight time in it :-)
>
> But as nice as the plane seems to be, I'm in the phase right now of analyzing
the heck out of everything to make sure it's operating as it should (fortunately,
I have some AFS EFISes in there that log data for me to go over afterwards).
And though the plane is operating 99% as well as I hoped for, there are a
couple of things not operating quite as I expected - I'm after other people's
advice to see if they've experienced something similar. Any help or insight
anyone can give on any of these issues would be greatly appreciated!
>
> My plane is a pretty standard build with a factory-new Lycoming IO-540 D4A5 and
3-bladed MT prop.
>
>
>
> 1. Fuel pressure drop climbing to higher altitudes: Today, I did an "informal"
climb at 110 KIAS and 2500 RPM/full throttle/full rich to 10000' to see how
it would handle it. At around 3200' MSL, I see a fuel pressure of about 21psi
with the engine pump (boost pump off). But in the climb, the fuel pressure
drops significantly. At 5000', it's at 18psi, at 7000' it was about 16psi, then
it started dropping faster. At 8000' it was down to 13psi and by 8700' had
dropped down to 11psi. I turned the boost pump back on and it promptly shot
back up to 20psi, so I continued the climb to 10000' and then made my way back
down. By the time I got back down to 4300' I turned the boost pump off and
the engine pump maintained pressure at 22psi. I never did take the chance to
level out and test pressure further - without knowing if it was a significant
cause for concern, I got back down to the lower altitudes instead. I haven't
seen any significant pressure fluctuations in flying a!
> round under 5000'.
>
> According to the Lycoming manual, the fuel pressure for the IO-540-D4A5 at the
fuel injector is supposed to be between 14 and 45 psi. This is where the Van's
stock fuel pressure sensor is measuring, isn't it? Though I've seen at least
two other pilot's RV-10 POHs that use numbers for the acceptable pressure
to be what Lycoming quotes as that for the inlet to the fuel pump of -2 to 35
psi, so it's got me wondering if I'm misinterpreting either the Lycoming documentation
or the fuel plumbing. So the question I have - is that low fuel pressure
the cause for concern I think it is? If so, what might be causing it, and
how would I fix it? Or is it normal? What do other people see in climb to 10000'?
Though I can use the boost pump for climbs to higher altitudes (and I've
heard of some certified aircraft that suggest it), it doesn't strike me as
an appropriate measure if the boost pump were to fail.
>
>
>
> 2. Rate of climb at high altitudes: I haven't constructed the wheel pants yet,
so I know performance will improve when they're done. At low altitudes I
certainly can't complain about rate of climb - with 450 pounds of fuel and me,
I did a short field takeoff today climbing out at about 85 knots and saw a 2150
fpm climb rate. But when I got up near the 10000' point, at 110 KIAS, I was
only getting around 500 fpm. I haven't done proper climb charts yet, but since
I've heard of lots of people cruising in the RV-10 at 15000'-17000', how are
they getting up there? My climb was at full rich, as I've been taught to do
in lower performing planes - is it standard practice to lean out the mixture
in climbs up at that altitude for more power? Or perhaps a slower climb speed/steeper
angle than my 110 KIAS?
>
>
>
> 3. Performance in general: I did some airspeed indicator calibrations today
at different power settings at 3200', and ended up with the following true airspeeds:
25"/2500RPM: 150 knots, 24"/2400 RPM: 147 knots, 23"/2300 RPM: 141 knots,
21"/2300 RPM: 134 knots, 18"/2300 RPM: 118 knots, 16"/2200 RPM: 103 knots.
These numbers are without wheel pants, but with that in mind, do they seem reasonable?
Vans' web site suggests cruise at 171 knots at 75% power at 8000'.
I know that claims should be taken with a grain of salt, and I didn't run these
tests at 8000', but if my calculations are correct, at 25"/2500 RPM I should
have been producing about 80% power. Is it expected that the wheel pants and/or
a higher altitude are going to make a significant enough improvement to
get closer to Van's numbers?
>
>
>
> 4. CHT temps: To break in the engine, I've been running it pretty hard - usually
around 25"/2500 most of the time (with some cycling to 25"/2600 or down
to 24"/2400 to avoid building a ridge in the cylinder). In cruise with those
power settings, my cylinders 3 and 4 run comparatively cool at around 375F. Cylinders
2, 5, and 6 are about 410F, but cylinder 1 is a bit of an anomaly. Usually
it's the hottest of all, getting up to around 440 (5 degrees hotter than
Lycoming's recommendation for maximum service life), though there have been
a few times where it's dropped rather abruptly by 50-60 degrees (for no apparent
reason I can see), making it surprisingly suddenly the coolest cylinder. But
it doesn't stay there - after awhile, it climbs back up to step in line with
what cylinders 2, 5, and 6 are doing... but usually stays 20-30 degrees hotter
than the rest. Outside temperatures have been around 30-40 Fahrenheit during
the flights so far.
>
> Of course, at lower power settings, the CHTs all drop down to well under 400.
And all power settings, the engine operation has been very smooth - no roughness
at all.
>
> I can reduce the height of the dam in front of cylinder 1, and I've heard of
lots of people having to do that. But especially with the strange temperature
fluctuations I'm still not sure if it's fully broken in yet, so I've been holding
off until things settle. Has anyone else noticed a hot cylinder 1, and if
so, how much of the front dam did you remove to cool it down? The good thing
is my centre two cylinders seem plenty cool so I should be able to sacrifice
some of their airflow to get #1 down.
>
>
>
> 5. Break in: I've flown the engine pretty hard now for 9 hours, but haven't
seen any dramatic sign of CHTs reducing as is supposed to happen with a break
in (with that said, the engine was run in at Lycoming for about an hour, and
about 45 minutes on the ground under supervision of an aircraft engine shop for
further break in before first flight). Other indications like "until the oil
consumption has stabilized" haven't helped either - I put in about 3/4 quart
of oil at about the 6 hour mark, but that's been it.... so far, it hasn't used
excessive oil, and as I've only added oil once, I'm unsure of how to even define
"stabilized". Now that I'm at the 9 hour mark for flight (11 hours on the
engine overall), should I conclude that the engine is probably broken in about
as good as it's going to get, or should I still be holding out for a noticeable
drop in CHTs?
>
>
>
> Sorry for the long email! But if anyone has any suggestions, advice, or comments
on any of these or other issues, I'd certainly appreciate hearing from you!
>
> I'm looking forward to meeting with some of you at fly ins, as soon as I finish
flying off the 25 hours I need to do first!
>
> Dan
> ---
> Dan Charrois
> President, Syzygy Research & Technology
> Phone: 780-961-2213
>
>
>
>
>
Message 4
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| Subject: | Re: Another RV-10 flying! (with some performance questions) |
Big congratulations. Makes all the work worth it. My first flight was last
April.
On Sun, Jan 29, 2017 at 6:07 AM, Jesse Saint <jesse@saintaviation.com>
wrote:
>
> 1. A lot of the RV-10's do this. I know people who have changed out their
> engine driven pumps thinking they were going bad and nothing changed. The
> main thing to monitor is if your engine starts leaning out or stumbling
> because of it. If everything is smooth, then it's not a problem. The
> pressure at the inlet to the pump has a much different range because it can
> be sucking the fuel from a substantially lower point (the "-2") or it can
> be pressurized by the boost pump (the "35"). If stock, you are measuring at
> the pump outlet. Keep your eyes on it and you should be fine, but it
> doesn't hurt to run the boost pump for peace of mind.
>
I suspect that the fuel pressure pickup isn't plumbed correctly, or there
is an issue of a restriction somewhere in the lines between the tanks and
the fuel servo input. The pressure hose should be connected at the fuel
servo. I just went back and looked at my data from a few recent flights.
The only time my fuel pressure drops below 25 psi is when I push the
throttle in for take-off, where it may drop to 18 psi for a few seconds
before returning to above 25 psi. No change in fuel pressure up to 9800
density altitude, which is highest I have gone in recent flights.
The RSA fuel servo needs 15 psi to work correctly. If the boost pump
increases pressure by more than 2-3 psi, the mechanical pump is having to
work too hard.
I would be looking for restrictions, such as junk in the fuel filter, a
kink in plumbing, etc. Or there could be a small air leak into a fuel line,
allowing sucking of air that will reduce fuel pressure, even if there is no
leak. The boost pump giving a big boost implies that there is either too
much suction needed, or a leak. Early on, I had a few seeps in the lines,
wing to fuel selector to firewall. I went back in tunnel, installed a
paper towel at every connection, and made corrections to any that left any
fuel traces at all.
I modified my original fuel selector install, to get the valve and lines as
low as possible in the tunnel, because you don't want the valve looking
like a big inverted siphon that creates potential for vapor lock. Basically
spent the money to get extension for the Andair valve so I could move the
valve itself down, instead of being up at the top of the tunnel.
> 2. You should absolutely lean out the mixture as you climb. I start
> leaning by 1,500' usually. I lean the EGT's out to about 100-150 degrees
> ROP in the climb. You can find this number by seeing what your EGT's peak
> at. To do this, run 20" and 2400 rpm at 3,000' and lean until they peak. I
> see most peak at 1,425-1,450. If so, I climb with the hottest cylinder at
> 1,300-1,325, and keep leaning as I climb to keep it there. I run a little
> more rich if I need to for CHT's, but I never run WOT much above the
> pattern. This will make a huge difference in your power, especially as you
> approach 10,000'. I suspect that 1 and 2 are somewhat related. If you start
> to lean, your fuel flow will decrease as you climb, and your fuel pump will
> be able to maintain a higher pressure.
>
You can start your leaning where ever you choose. I lean generally to
maintain EGTs in the 1200 to 1300 range during climb starting at perhaps
3000 MSL, then lean to lean of peak once I level into cruise. It isn't
critical exact numbers in climb, just a twist occasionally to keep EGT in
that 1200 -1300 range which will be about 150-200 rich of peak. Or if you
are near sea level, see what your EGT is shortly after takeoff at full
rich. It should be in that range, but use whatever it is at as an upper
limit, and stay about 50 degrees cooler than that.
>
> 3. Some planes are faster than others and some are slower, but I have only
> seen a total speed fluctuation of less than 10 ktas. The MT prop is
> slightly slower than the Van's-used Hartzell. Some say it's the same, and
> others say it's 8 knots slower. It's somewhere in that range. The takeoff
> and climb is supposed to be better, which I suspect will prove true once
> you start leaning. The wheel pants and gear leg fairings, in my experience,
> add about 17 kts. That should get you fairly close to the Van's numbers. I
> suspect you will I prove speed by leaning. Run the speed tests at
> 6,000-8,000 density altitude. In my experience the absolute fastest is at
> about 6,500 density altitude, wide open throttle, matching prop rpm and
> about 15-16 gph fuel flow. Most RV-10's will get 174-183 ktas in this test.
>
I agree with Jesse. I have the MT prop. Once I got gear fairings installed,
I run about 160-165 TAS at power below 70% and 170-175 above 70% as long as
I am above 5500. Speed definitely improves with altitude, while fuel flow
decreases as power available decreases. I haven't done finish work on
fairings yet, so I may find a couple more knots when I do that and when I
get paint done. Your numbers are similar to what I had before I got the
wheel pants and fairings installed.
>
> 4. I suspect you have the air dam in front of Cylinders 1 and 2. Remove
> the dam from Cylinder 1 to see if that helps. I usually end up leaving
> those air dams out completely on both 1 and 2. I suspect it will. Then,
> increase your climb airspeed to lower those temps. Temps will come down as
> the engine breaks in, but those number are hotter than I like to see. Try
> to keep them below 400 if possible, and certainly below 420. The
> fluctuation seems to me to be more of a gauge issue than the cylinder. I
> assume these temps are all in climb. Take another look through your baffles
> and seal any spots where air can get to the lower cowl without going
> through the cylinder fins. These engines usually require at least half a
> caulk tube of RTV to seal well.
>
Spot on. I removed the air dams, and then when 5 and 6 ran hot with no
dams, used some aluminum tape on front two cylinders to achieve temp
balance. I may do small dams to match where I have the tape now. Definitely
use power and airspeed adjustments to keep CHT below 400. Your CHT will
come down once you get wheel pants on.
>
> 5. You may still get a decent drop in CHT's, but you may already be broken
> in most of the way. How high are you keeping your oil? I usually add 8
> quarts at a change including the filter, and add a quart when it gets to
> 6.5. I've seen these engines settle in at 5 hrs/quart to 20+ hrs/quart. It
> sounds like you are at about 8-10 now. See if that drops.
>
You will find an oil level that the engine likes. Right now mine is around
6 quarts in the sump. I hope to improve that with an air/oil separator on
the breather line. You probably have the engine 80% or more broken in.
There will be small improvements perhaps to 25-50 hours, but nothing like
the first 5-10 hours.
>
Kelly McMullen
40866 with about 90 hours of flying time
A&P/IA Technical Counselor
Message 5
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| Subject: | Re: Elevator Push Rod Issue |
That's what I did, after drilling them refitting was a pain, but the
cold/warm trick made it possible with little effort.
Cheers Werner
On 29.01.2017 06:21, David Saylor wrote:
> they're close, try heating the tube with a heat gun--not too hot--and
> putting the plug in a freezer for a while. For a close interference
> fit, that usually helps a lot.
>
> --Dave
>
Message 6
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| Subject: | Re: Elevator Push Rod Issue |
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Message 7
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| Subject: | Re: Another RV-10 flying! (with some performance questions) |
Excellent fuel pump reference (how the pump works, expected pressure
output, what happens to engine fuel flow if pressure is too low, etc):
https://www.youtube.com/watch?v=_BfwuUjh_lA
Data point: My AFS logs show 22-24 psi at 8500 on a flight a couple of
years ago. I've recently had fuel pressure drop to 18psi occasionally
(at lower altitude), and am in the process of replacing the engine
driven pump to address that. No results to report yet.
--
Tim Lewis -- HEF (Manassas, VA)
A&P
RV-6A N47TD -- 1104 hrs - sold
RV-10 N31TD -- 850 hrs
Dan Charrois wrote on 1/29/2017 4:34 AM:
>
> Hi everyone.
>
> I'm happy to say that after 11+ years of work, my RV-10 is finally in the air.
As a testament to Van's incredible design (both in terms of the airframe performance
and reliability, and perhaps equally importantly, in producing a kit
that newcomers to the idea of homebuilding can build safely) , the first flight
(and subsequent ones) have been pretty much uneventful. Everything "just works"
- the plane handles like a dream and I'm looking forward to spending thousands
of hours flying it. Still a ways to go yet - I'm currently at 9 hours
of flight time in it :-)
>
> But as nice as the plane seems to be, I'm in the phase right now of analyzing
the heck out of everything to make sure it's operating as it should (fortunately,
I have some AFS EFISes in there that log data for me to go over afterwards).
And though the plane is operating 99% as well as I hoped for, there are a
couple of things not operating quite as I expected - I'm after other people's
advice to see if they've experienced something similar. Any help or insight
anyone can give on any of these issues would be greatly appreciated!
>
> My plane is a pretty standard build with a factory-new Lycoming IO-540 D4A5 and
3-bladed MT prop.
>
>
> 1. Fuel pressure drop climbing to higher altitudes: Today, I did an "informal"
climb at 110 KIAS and 2500 RPM/full throttle/full rich to 10000' to see how
it would handle it. At around 3200' MSL, I see a fuel pressure of about 21psi
with the engine pump (boost pump off). But in the climb, the fuel pressure
drops significantly. At 5000', it's at 18psi, at 7000' it was about 16psi, then
it started dropping faster. At 8000' it was down to 13psi and by 8700' had
dropped down to 11psi. I turned the boost pump back on and it promptly shot
back up to 20psi, so I continued the climb to 10000' and then made my way back
down. By the time I got back down to 4300' I turned the boost pump off and
the engine pump maintained pressure at 22psi. I never did take the chance to
level out and test pressure further - without knowing if it was a significant
cause for concern, I got back down to the lower altitudes instead. I haven't
seen any significant pressure fluctuations in flying a!
> round under 5000'.
>
> According to the Lycoming manual, the fuel pressure for the IO-540-D4A5 at the
fuel injector is supposed to be between 14 and 45 psi. This is where the Van's
stock fuel pressure sensor is measuring, isn't it? Though I've seen at least
two other pilot's RV-10 POHs that use numbers for the acceptable pressure
to be what Lycoming quotes as that for the inlet to the fuel pump of -2 to 35
psi, so it's got me wondering if I'm misinterpreting either the Lycoming documentation
or the fuel plumbing. So the question I have - is that low fuel pressure
the cause for concern I think it is? If so, what might be causing it, and
how would I fix it? Or is it normal? What do other people see in climb to 10000'?
Though I can use the boost pump for climbs to higher altitudes (and I've
heard of some certified aircraft that suggest it), it doesn't strike me as
an appropriate measure if the boost pump were to fail.
>
>
> 2. Rate of climb at high altitudes: I haven't constructed the wheel pants yet,
so I know performance will improve when they're done. At low altitudes I
certainly can't complain about rate of climb - with 450 pounds of fuel and me,
I did a short field takeoff today climbing out at about 85 knots and saw a 2150
fpm climb rate. But when I got up near the 10000' point, at 110 KIAS, I was
only getting around 500 fpm. I haven't done proper climb charts yet, but since
I've heard of lots of people cruising in the RV-10 at 15000'-17000', how are
they getting up there? My climb was at full rich, as I've been taught to do
in lower performing planes - is it standard practice to lean out the mixture
in climbs up at that altitude for more power? Or perhaps a slower climb speed/steeper
angle than my 110 KIAS?
>
>
> 3. Performance in general: I did some airspeed indicator calibrations today
at different power settings at 3200', and ended up with the following true airspeeds:
25"/2500RPM: 150 knots, 24"/2400 RPM: 147 knots, 23"/2300 RPM: 141 knots,
21"/2300 RPM: 134 knots, 18"/2300 RPM: 118 knots, 16"/2200 RPM: 103 knots.
These numbers are without wheel pants, but with that in mind, do they seem reasonable?
Vans' web site suggests cruise at 171 knots at 75% power at 8000'.
I know that claims should be taken with a grain of salt, and I didn't run these
tests at 8000', but if my calculations are correct, at 25"/2500 RPM I should
have been producing about 80% power. Is it expected that the wheel pants and/or
a higher altitude are going to make a significant enough improvement to
get closer to Van's numbers?
>
>
> 4. CHT temps: To break in the engine, I've been running it pretty hard - usually
around 25"/2500 most of the time (with some cycling to 25"/2600 or down
to 24"/2400 to avoid building a ridge in the cylinder). In cruise with those
power settings, my cylinders 3 and 4 run comparatively cool at around 375F. Cylinders
2, 5, and 6 are about 410F, but cylinder 1 is a bit of an anomaly. Usually
it's the hottest of all, getting up to around 440 (5 degrees hotter than
Lycoming's recommendation for maximum service life), though there have been
a few times where it's dropped rather abruptly by 50-60 degrees (for no apparent
reason I can see), making it surprisingly suddenly the coolest cylinder. But
it doesn't stay there - after awhile, it climbs back up to step in line with
what cylinders 2, 5, and 6 are doing... but usually stays 20-30 degrees hotter
than the rest. Outside temperatures have been around 30-40 Fahrenheit during
the flights so far.
>
> Of course, at lower power settings, the CHTs all drop down to well under 400.
And all power settings, the engine operation has been very smooth - no roughness
at all.
>
> I can reduce the height of the dam in front of cylinder 1, and I've heard of
lots of people having to do that. But especially with the strange temperature
fluctuations I'm still not sure if it's fully broken in yet, so I've been holding
off until things settle. Has anyone else noticed a hot cylinder 1, and if
so, how much of the front dam did you remove to cool it down? The good thing
is my centre two cylinders seem plenty cool so I should be able to sacrifice
some of their airflow to get #1 down.
>
>
> 5. Break in: I've flown the engine pretty hard now for 9 hours, but haven't
seen any dramatic sign of CHTs reducing as is supposed to happen with a break
in (with that said, the engine was run in at Lycoming for about an hour, and
about 45 minutes on the ground under supervision of an aircraft engine shop for
further break in before first flight). Other indications like "until the oil
consumption has stabilized" haven't helped either - I put in about 3/4 quart
of oil at about the 6 hour mark, but that's been it.... so far, it hasn't used
excessive oil, and as I've only added oil once, I'm unsure of how to even define
"stabilized". Now that I'm at the 9 hour mark for flight (11 hours on the
engine overall), should I conclude that the engine is probably broken in about
as good as it's going to get, or should I still be holding out for a noticeable
drop in CHTs?
>
>
> Sorry for the long email! But if anyone has any suggestions, advice, or comments
on any of these or other issues, I'd certainly appreciate hearing from you!
>
> I'm looking forward to meeting with some of you at fly ins, as soon as I finish
flying off the 25 hours I need to do first!
>
> Dan
> ---
> Dan Charrois
> President, Syzygy Research & Technology
> Phone: 780-961-2213
>
>
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