Uh-oh. engine trouble? not again!!!

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speed150mph
Airman
Posts: 15
Joined: 30 Jan 2013, 22:09

Uh-oh. engine trouble? not again!!!

Post by speed150mph »

Okay so heres the scoop on my fort. I was about half way through a flight over water in fairly good weather, flying at 16,000 ft. Plane was flying beautifully, the engine instruments were all in the green, and close to each other. Then I get the call from my Flight engineer, we have a problem in engine 3. So I look through my instruments, and they are good. I look at the engine for weird or excessive vibrations, smoke, ect. and it seems to be running fine. That immediately makes me think hmmmm... gotta be a bad cylinder.

And why did I immediately think that? Because it isn't the first time with this plane that I've been flying along and dropped a cylinder. Actually, this would be the third time that it has happened. Now I know its not from normal wear. I have a total of 14 hours on these engines, and my wear rate is set at normal. Im running the proper oil viscosity and high grade fuel.

So I've figured that it is probably something im doing to the old girl that is causing me to drop cylinders, but what could I be doing? If you have any questions about my engine handling techniques, feel free to ask.

robert41
Senior Master Sergeant
Posts: 1538
Joined: 02 Jan 2006, 20:42
Location: WI USA

Re: Uh-oh. engine trouble? not again!!!

Post by robert41 »

Need a little more information.
I have the occasional cylinder fail also.
What is your MP and RPMs when climbing and cruising? Do you let the copilot take the RPM, cowl flaps and intercoolers?
Are the FSX realism settings per the manual?
You have all the B17 updates?

N1684T
Staff Sergeant
Posts: 280
Joined: 02 Oct 2010, 22:17
Location: Texas, USA

Re: Uh-oh. engine trouble? not again!!!

Post by N1684T »

The first thing that comes to mind for me, is be careful on descent's that is watch those engine temps. closely espically from high altitudes I have lost a couple of cylinders in this way in the past. Around 190 or above on all engines.

Hope this help's / She fly's like dream, but can be a beast if mishandled.
Mark S.
Boeing B-17G Flying Fortress-Accusimed/Boeing 377 Stratocruiser-COTS/ Piper Cub-Accusimed/Cessna 172 Trainer/Piper Cherokee 180/T-6 "TEXAN"/Constellation L049

speed150mph
Airman
Posts: 15
Joined: 30 Jan 2013, 22:09

Re: Uh-oh. engine trouble? not again!!!

Post by speed150mph »

I follow the guide in the checklist window. My co-pilot monitors props, cowl flaps, and intercoolers. I take it easy on the girl and take-off using 7" on the MP selector, not 8. after i have gear up, I climb up to about 7-8000 ft at 38" and co-pilot has props at 2300, at 8000, I back it off to 35" and 2300, and open ram airs. at 10,000 I swtich fuel boost pumps on and mitxtures to auto-lean and throttle down to a nice cruise. below 20,000 my 17 wont fly the recommended auto-lean speed of 150mph, my airspeed needle seems to pin itself on 190, lest i throttle back and get an ear full about carb air temps. and my engines get hot at take-off and early climb, at take-off they get up to about 210, and until about 5000ft they stay between 206-208, then ussually settle down to 203-205 unless at high altitude, then they sit at about 197. my oil temperatures are always however, about 80 which according to the guage is just below their recommended upper limit.

And I cant say I monitor the CHT on decent as much. im in a contant battle of setting throttles and boost in a balacing act of keeping airspeed below 200, and keeping carb air temps above 10 degrees. I give it the usual visual sweep, and while it comes close to it, It doesnt go below the lower limit. ill definately be keeping a closer watch on it.

but can someone help me with this possibly, in a decent for approach, how should I be doing this in order to maintain proper CHT's and CAT's and keeping airspeed down below 200 mph, and what distance should I begin my decent? as it sits, depending on my altitude I usually start decent between 80-50 miles away and decend at 500 ft/min. would I be better starting my decent earlier and decending with a higher power setting at a lower decent rate?

Gypsy Baron
A2A Master Mechanic
Posts: 3396
Joined: 02 Aug 2008, 17:04
Location: San Francisco

Re: Uh-oh. engine trouble? not again!!!

Post by Gypsy Baron »

On the subject of descent....I run the turbo dial up to "8" and reduce throttles to hold my speed. This will
generally maintain an acceptable carb temp.

You may just have been stuck with a 'virtual lemon' when it comes to losing cylinders...that's the
beauty of Accu-Sim :)

I have over 850 hours on my airframe and #1, 3 & 4 engines just a couple of hours shy of that. I had to replace
#2 some time ago and it only has around 700 hours on it. All engines are "like new".

I do suffer an occasional loss of a cylinder and other minor issues but I try to treat the engines with care. I have
had to run 39-39" of MP for extended periods of time when flying 91st Bombardment Group missions if I happen
to be stuck with the odd unfavorable head wind while others in the formation have tail winds (dam you M$ weather engine!)
But I try to not exceed 38" MP except during the takeoff roll.

Another point, before shutting down, wait for the CHT's to get below 190C to avoid detonation damage. On warm days
when the CHT's come down very slowly I select full rich mixture and set the idle RPM at just above the point where my
co-pilot makes a comment :) To shut down, I open the fuel valves while keeping the fuel pumps on.

If I open all valves at once, my #4 will run on for 10 or 20 seconds longer than the other 3 engines. Just another
Accu-Sim 'feature' for my particular aircraft.

When I first joined the 91st BG and was flying the 'probationary' paint B-17G on the Hop Program, I was
having maintenance issues almost every flight, before I finished the first 2 phases of the program and
'earned my own paint'..."Fearless Fosdick". By then I could fly the 17 without breaking things...too much!

And now I come back from a 4-5 hour mission and find a 'clean slate' in the Maintenance Hangar almost
every time.

Paul
Image
Last edited by Gypsy Baron on 03 Jun 2013, 10:52, edited 1 time in total.

robert41
Senior Master Sergeant
Posts: 1538
Joined: 02 Jan 2006, 20:42
Location: WI USA

Re: Uh-oh. engine trouble? not again!!!

Post by robert41 »

Your settings sound pretty good.
For decents, I keep the MP no less than 29, turbo at 6 to 8 depending on the outside temps, 500 to 700 fpm rate. Copilot takes the RPMs, cowl flaps, and intercoolers.
Depending on altitude, lets say at 20000ft, I will start down 150 to 200mi out.
If I get a "carb temps too low", increase turbo, add MP. Keeping the MP in the green, 29 to 34 seem to be the best setting.
Control your air speed with the rate of decent.
Normally, unless on a very long flight, I run auto rich all the time.

N1684T
Staff Sergeant
Posts: 280
Joined: 02 Oct 2010, 22:17
Location: Texas, USA

Re: Uh-oh. engine trouble? not again!!!

Post by N1684T »

Good read on Paul and Roberts replies, thanks guy's for the input a lot of experience there on the girl.
Don't want too hack the thread so I will zip it. :mrgreen:
Mark S.
"Texas Bronco" 323rd BG
Boeing B-17G Flying Fortress-Accusimed/Boeing 377 Stratocruiser-COTS/ Piper Cub-Accusimed/Cessna 172 Trainer/Piper Cherokee 180/T-6 "TEXAN"/Constellation L049

speed150mph
Airman
Posts: 15
Joined: 30 Jan 2013, 22:09

Re: Uh-oh. engine trouble? not again!!!

Post by speed150mph »

thank you all for the advice. I try to fly my aircraft as easy as possible, and I rarely have any mechanical issues (besides "crash damage" when fsx spawns me in a fuel pump... grrr...) I try to fly by the manual, and for the most part its gone well.

and i wish i was still in the 91st, but I had to let it go since my fsx has issues.

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