Re: Turbo engine maintenance

On Thu, 6 Oct 2005 18:31:27 -0700, "Matt Barrow"
<mattbarrow@xxxxxxxxx> wrote:

snip

>> How does Avweb differ from "the logical fallacy of Argument From
>> Authority"?
>
>They demonstrate the data and reasoning behind their positions.

You might be surprised that I've corresponded with the Deakin dude,
and WRT "factory" turbo Lycoming ops we tended to agree-go figure.

snip
>> I'm going to try and keep this simple. The original poster is thinking
>> about buying one of the most problematic (in my personal experience)
>> GA turbo-charged aircraft/engine combos. It is rather obvious that his
>> personal knowledge WRT operation of any turbo-supercharged aircraft is
>> lacking. Running this engine ROP, even waaay ROP is less likely to put
>> him the position to do very bad things.
>
>I think you're confusing the GSIO model, which is what TAT/GAMI is running
>on their test bed...on mogas and other rotgut fuel -- without a hitch,

I really don't believe that I am confused concerning the relative
reliablility/common maintenance issues vs. standard operational
procedures on turbocharged Lycomings derived from my personal
experience out on the hangar floor.

>> It takes some specific know-how to do "the big pull" on any engine,
>> and I will definitely agree that 50-75 degrees ROP is the worst
>> possible place to be. BTW, following the turbo Lance/'Toga POH %power
>> chart MAP/RPM/ITT/FF settings is practically guaranteed to reduce
>> engine/cylinder longevity. The only one I personally aware of that is
>> worse is the original PA46-350P POH numbers.
>>
>> snip
>>
>>>Yes...so?
>>
>> As I recall, I initally suggested that someone considering operating a
>> TIO540 LOP should get more information WRT detonation from the one
>> person in the industry that is likely to have that information. As it
>> happens, the article you referred to mentions this same issue, but not
>> this particular engine.
>
>GSIO, not the TIO.

GSIO what? With regard to what? If Mr. Braly says that he has data on
the TIO540-S1AD, and detonation is not an issue between 50 LOP and 100
ROP at/above 75%, I would tend to take his word for it. However, if he
says that he has similiar data on the -J2BD, we are going to disagree.

I have seen it. In fact, while attempting to determine it's cause, I
eliminated mechanical malfunction/failure of the ignition, fuel
metering & delivery, turbocharger & control systems and had the fuel
remaining in the tanks tested.

The engine in question was nearly new, and belonged to a gentleman
that is now the largest civilian G1 operator and useta be (maybe still
is) the largest civilian Lear operator in the world. Way back when he
owned a couple of Beech 18's, a ratty old Navajo, and was leasing a
couple of Lears.

The only factor we weren't able to eliminate was the ex turbine
helicopter pilot that was yanking and cranking on the knobs sticking
out of the pedestal. The starboard engine was virtually run-out, which
we guessed was enuff to get it just out of the detonation range.

snip

>> I would further reason, based on IO-550 experience that the TO FF's
>> need to be increased slightly after adding the "TN" to the IO-
>> engine. The wonderful self-leaning fuel pump used on the
>> normally-aspirated 550 was notorious for running too lean ROP/too hot
>> in TO/climb.
>
>What TAT recommends is ensuring the your TO FF is NO LESS than redline.

Afraid that this is a somewhat fallacious statement. There is a quite
specific procedure for testing and properly adjusting the classic TCM
fuel injection system. There are absolute fuel pressure and flow
ranges established. The smart money has always been on pushing the
high end of the scale and having it checked periodically.

On the IO-550-B, this range was tweaked "up" via SB after A36's
started shedding e-valve guides. Prior to adjustment, following POH
operating procedures, I have seen nearly new IO-550's with the
auto-lean pump (borrowed from TSIO apps) that "automatically"
maintained 50-75 degree ROP climbing to altitude.

Unfortunately, as I recall, the adjustment procedure does not require
calibration or verification of the on-board mechanical fuel flow
(pressure) gage. Quite often, a properly set-up -B will exceed the
indicated "redline" slightly rolling down the runway.

Granted, if you are operating LOP, this is only going to be an
operational factor during TO and initial climb.

I'm curious how the auto-lean pump (if indeed it is still present on
your engine) is plumbed. On the straight IO the line that would
typically connect to the upper-deck on a TSIO install was vented to
ambient-dropping the max metered fuel pressure as ambient pressure
dropped in the climb.

>> I would also guess that there likely is a warning to avoid all
>> operation between approx. 50 degrees LOP and 100 degrees ROP at high
>> power settings. This again, would likely be to avoid detonation.
>
>They call it the "Red Box"
>
> Red Box = No Fly Zone
> At and below about 60% power, there is no red box.
> At about 65% power or so, 100ºF ROP to Peak.
> At about 70%, 125ºF ROP to 25ºF LOP.
> At about 75%, 180ºF ROP to 40ºF LOP.
> At about 80%, 200ºF ROP to 60ºF LOP

Makes sense to me, but is this TAT TNIO-550 specific, or generic
APSeminar LOP info?

>> (17+ years allegedly maintaining TIO-540-J2B, J2BD, F2BD, S1AD, AE2A &
>> V2AD's for 100,000+ hours of operation with minimal "burps" if
>> operated IAW Lyc SI1094D C. 7. & 9.)
>
>Then, of course, Lycoming has this take:
>http://www.avweb.com/news/columns/182131-1.html, but they must have more
>credibility since they're no on the Internet. :~)

Read it when the Deakin dude wrote it. But to paraphrase, SI1094D C7&9
recommends running their turbocharged engines at 65% 125 degrees ROP
"for optimum service life", not the 50 degrees mentioned in the
article.

Again, I have repeatedly seen what happens when you run at 75% at peak
or 50 degrees ROP (elevated CHT and oil temp, accelerated e-valve
guide wear), I don't need to read about it...

Regards;

TC
.

Relevant Pages

  • Re: Fuel Prices and their Effect on Your Flying
    ... squared and 20-30 LOP. ... I know that this will not work for everyone but for my IO-360 it gives me a cool, smooth running engine that is only drinking 9.5 GPH. ... At about 65% power, 100ºF ROP to Peak. ... Fuel here is $4.15, up from $3.45 so it translates to about $11 more an hour. ...
    (rec.aviation.owning)
  • Re: Scientific Data on Engine Operations
    ... Because LOP saves fuel and keeps plugs clean. ... this correlates to long term engine longevity is unknown. ... >See any of them about the combustion event and TDC. ... of a product, not an operating regime. ...
    (rec.aviation.owning)
  • Stuart Turner stuff
    ... Stuart Turners and seven other companies were approached by the War ... Office to see if they could produce a light weight air cooled engine to ... capable of operating in any temperature from freezing to 140oF and govern ... lightweight steel tubular frame that was probably enclosed with a shaped ...
    (uk.rec.engines.stationary)
  • Re: Fuel Flow and Peak EGT
    ... While flying to FL from NJ last week I did what I always do and fly ROP by ... I know enough about LOP to know I will not operate LOP without an engine ... If you keep running in that area you might not have your engine long ...
    (rec.aviation.owning)
  • Re: Injection Limiter adjustment
    ... This is where the objective of operating manuals diverges from engineering. ... The first engagement of a marine engine on a docked boat is often a fairly ... I warm up the full five minutes ...
    (rec.boats.cruising)