Small world at Oshkosh
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blaswichk
Re: Small world at Oshkosh
Oooops, I just found out, and wasn't used to the acronym.
kb
kb
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fgayford
Re: Small world at Oshkosh
Hi Richard
I had all kinds of problems with my 503 when I got it.
Everything temp wise was out of wack.
I watched Brian Carpenters webinar "Is your two stroke engine about to fail"
I must be a little slow because I had to watch it about three times to really understand.
It solved my problems.
The biggest problem I had was skunky stale gas. Drain your tank completely if you suspect your gas is old. The prop loading was the key to getting my EHT temp right.
Fred
I had all kinds of problems with my 503 when I got it.
Everything temp wise was out of wack.
I watched Brian Carpenters webinar "Is your two stroke engine about to fail"
I must be a little slow because I had to watch it about three times to really understand.
It solved my problems.
The biggest problem I had was skunky stale gas. Drain your tank completely if you suspect your gas is old. The prop loading was the key to getting my EHT temp right.
Fred
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dickoreilly
Re: Small world at Oshkosh
Kess, Fred
Brian Carpenter's webinair is good. I watched it last fall after I signed up for
the repairman course and used it in doing my carb rebuild and other tasks.
My engine runs beautifully now and there are no longer any air bubbles in my
fuel line. But Mark says my egt is too cool for best fuel economy and best
engine life. Hence I'm going down his suggested path of fixing that.
First step is getting digital measurements with the EIS instead of relying on
the gauges, although they work quite well, are very nicely in sync, and are fed
with recent prob replacements and replacement extension wires. But I can't
really discern less than about 100 degree differences by eyeball from piloting
position.
Mark suggests dropping the needles one notch and seeing what happens. If that
doesn't get me to at least 1100 and preferably 1150, then try the next
smallest main jet. But be careful.
My plane had the Rotax HAC (High Altitude Compensation) carb system when I
bought it and had been running with it for the 10 years that previous owner had
the plane. He didn't know whether the original 1998 owner bought it that way
from Getting ready to do that led me to discover that Lockwood's catalog and
Green Sky's website, which are the only two sources of Rotax HAC (High Altitude
Compensation) system jetting, list different needles, clip positions and mains.
Currently I'm using the Green Sky specs (11K2, second clip position, 185 main).
Lockwood lists 15K2 needles in position 3 with 195 jets for the 503 dual carb,
no intake silencer, HAC system.
When I rebuilt the carbs last fall I found they had 8L2 needles in position 1,
with 158 jets, which are standard sea level jets for dual carb 503s without the
HAC system. I also found that the HAC compensator position was so far
compressed that the system was never actuating, so really I was just running sea
level carbs with no compensation, but a lot of extra plumbing. The plane
performed very well despite that. I followed Green Sky's instructions for
adjusting the compensator.
When I get home my first action will be to try to resolve those discrepancies.
Since Lockwood now offers the complete Rotax HAC kit in its catalog for about
$970, I'm inclined to believe that their specs are the best. Green Sky offered
HAC kits early last decade, when its HAC specs were put on the website, but now
offer only their alternative inflight adjustable compensation system.
Once I get the jetting specs nailed down, and the EIS installed, I'll start
tinkering. Meanwhile I'll fly with current settings which allow the plane to fly
well but maybe at the expense of a little more fuel usage than needed.
The other thing I took away from Mark's comments at the HKS turbo forum at
Oshkosh was that a fixed-pitch prop does not allow as much control over loading
the 503 as desired.
My plane used to have an in-cockpit pitch controlled IVO prop hub. But it failed
before I bought the plane and the previous owner replaced it with a
ground-adjustable hub. I have a box full of the old hub parts, plus the cockpit
switch, which I removed. I'm going to talk to IVO Prop, which is an hour from my
home, about fixing or replacing the old in-cockpit control system.
I like the fact that you can climb out at up to 1200 fpm Kess. I climb about
around 700 fpm. Of course, my airport is at 3230 agl and in the California
desert, so density altitude often is in the 6000-7000 ft range. The Gull
performs well in those conditions, but I'm sure it would perform better if I
could tune the pitch for the task -- climb or cruise.
Gas quality has never been a problem for me. I fly often enough to keep it
fresh. The exception was when the plane was apart for painting, fuel line
replacement, etc. For that I pumped the tank dry into my gas cans and poured the
gas into my truck, where it was quickly burned with no problems.
If anybody has any further knowledge on the HAC jetting issue, please share.
Also, if anyone can explain how the system adjusts mixture, I'd love to
know. The best that I can figure out is that the compensator valve changes the
air pressure in the float chambers, which in turn changes the float levels
slightly to cause a change in mixture. But I don't really understand how that
actually works or how a slight change in float level would change mixture. And
maybe I misunderstand the whole system.
Dick O'Reilly
Brian Carpenter's webinair is good. I watched it last fall after I signed up for
the repairman course and used it in doing my carb rebuild and other tasks.
My engine runs beautifully now and there are no longer any air bubbles in my
fuel line. But Mark says my egt is too cool for best fuel economy and best
engine life. Hence I'm going down his suggested path of fixing that.
First step is getting digital measurements with the EIS instead of relying on
the gauges, although they work quite well, are very nicely in sync, and are fed
with recent prob replacements and replacement extension wires. But I can't
really discern less than about 100 degree differences by eyeball from piloting
position.
Mark suggests dropping the needles one notch and seeing what happens. If that
doesn't get me to at least 1100 and preferably 1150, then try the next
smallest main jet. But be careful.
My plane had the Rotax HAC (High Altitude Compensation) carb system when I
bought it and had been running with it for the 10 years that previous owner had
the plane. He didn't know whether the original 1998 owner bought it that way
from Getting ready to do that led me to discover that Lockwood's catalog and
Green Sky's website, which are the only two sources of Rotax HAC (High Altitude
Compensation) system jetting, list different needles, clip positions and mains.
Currently I'm using the Green Sky specs (11K2, second clip position, 185 main).
Lockwood lists 15K2 needles in position 3 with 195 jets for the 503 dual carb,
no intake silencer, HAC system.
When I rebuilt the carbs last fall I found they had 8L2 needles in position 1,
with 158 jets, which are standard sea level jets for dual carb 503s without the
HAC system. I also found that the HAC compensator position was so far
compressed that the system was never actuating, so really I was just running sea
level carbs with no compensation, but a lot of extra plumbing. The plane
performed very well despite that. I followed Green Sky's instructions for
adjusting the compensator.
When I get home my first action will be to try to resolve those discrepancies.
Since Lockwood now offers the complete Rotax HAC kit in its catalog for about
$970, I'm inclined to believe that their specs are the best. Green Sky offered
HAC kits early last decade, when its HAC specs were put on the website, but now
offer only their alternative inflight adjustable compensation system.
Once I get the jetting specs nailed down, and the EIS installed, I'll start
tinkering. Meanwhile I'll fly with current settings which allow the plane to fly
well but maybe at the expense of a little more fuel usage than needed.
The other thing I took away from Mark's comments at the HKS turbo forum at
Oshkosh was that a fixed-pitch prop does not allow as much control over loading
the 503 as desired.
My plane used to have an in-cockpit pitch controlled IVO prop hub. But it failed
before I bought the plane and the previous owner replaced it with a
ground-adjustable hub. I have a box full of the old hub parts, plus the cockpit
switch, which I removed. I'm going to talk to IVO Prop, which is an hour from my
home, about fixing or replacing the old in-cockpit control system.
I like the fact that you can climb out at up to 1200 fpm Kess. I climb about
around 700 fpm. Of course, my airport is at 3230 agl and in the California
desert, so density altitude often is in the 6000-7000 ft range. The Gull
performs well in those conditions, but I'm sure it would perform better if I
could tune the pitch for the task -- climb or cruise.
Gas quality has never been a problem for me. I fly often enough to keep it
fresh. The exception was when the plane was apart for painting, fuel line
replacement, etc. For that I pumped the tank dry into my gas cans and poured the
gas into my truck, where it was quickly burned with no problems.
If anybody has any further knowledge on the HAC jetting issue, please share.
Also, if anyone can explain how the system adjusts mixture, I'd love to
know. The best that I can figure out is that the compensator valve changes the
air pressure in the float chambers, which in turn changes the float levels
slightly to cause a change in mixture. But I don't really understand how that
actually works or how a slight change in float level would change mixture. And
maybe I misunderstand the whole system.
Dick O'Reilly
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fgayford
Re: Small world at Oshkosh
Hi Dick
Reading your plugs is a good way to tell if you are too extreme in the rich or lean territory.
I took my plugs to Sun N fun for Brian Carpenter to look at. He said that because our planes are so clean it is hard to get the mix right. He said my plugs looked good.
I also got to show Lockwood who said the same thing.
Fred
Reading your plugs is a good way to tell if you are too extreme in the rich or lean territory.
I took my plugs to Sun N fun for Brian Carpenter to look at. He said that because our planes are so clean it is hard to get the mix right. He said my plugs looked good.
I also got to show Lockwood who said the same thing.
Fred
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Rahul
Re: Small world at Oshkosh
i double-checked her spot/blog. field landing after engine trouble, and a summersault! She'll reach home safe now, by truck, seems to be in a good mood. Hope her companions reach home safely too. Really love her awesome spirit, and then way too many surprises. Wonder what the wardens of these events say about such rare saddening mishaps. i mean, the delhi half marathon over the last five years has been shifted by a few weeks every year to keep things cool (just did the first two, mostly walking)
Mark, the Gull would never summersault in similar conditions, true?
Rahul
Mark, the Gull would never summersault in similar conditions, true?
Rahul