Problem with engine settings

[stretch1365]

Hi all,

Very bad of me I know, but today I flew the Stratocruiser for the first time in months after installing the Weathership addon found here in the forum. Well if A2A keep bringing out new planes something will get left languishing in the back of the hanger.

Anyway I decided to fly from Bruntingthorpe in the UK to Weathership "Mike" off the coast of Norway, a training flight if you like. I loaded up the Strat with a full cargo load of 17100lbs and supplies of 690lbs, but only 16 passengers.........I wanted lots of snacks on the flight see.

I took off and managed to get to 10000ft with the flight engineer controlling most things, me just doing MP and RPM, but I couldn't achieve the engine settings as stated in the manual or the "Crew Report" page. The best I could achieve being 2300rpm, 45" MP but only 92psi torque...........This only allowed a cruising speed of 160 knots airspeed. The settings should be 2100rpm, 40"MP and 168 PSI.............I couldn't climb above 10000ft either which was a pain as I am sure a higher altitude would have been much better and more comfy for my passengers too. I know the aircraft was heavy but I would have expected higher performance than what I actually saw on the flight. Was it the weight that caused my problems?

Reading the manual to see what I was doing wrong, the only thing I could see is that the power of the engines is taken more from the torque settings than Manifold Pressure, but how do I alter the torque and keep the MP at the required setting, if I increase the throttles appear to increase the MP not the torque!

Any help would be greatly received.

Oh the Weather ship worked a treat, thanks to Finn for doing that so long ago!

[dacamp66]

I believe the technique is to set MP, then set RPM, then adjust MP to get the desired BMEP (Brake Mean Effective Pressure) the MP shown is just to get you "in the neighborhood".
also, propliners of that era used a technique called "step Climb" basically, you climb until you can no longer maintain optimum climb speed using recommended power settings, then you level off and set cruise power and hold altitude until you approach recommended max cruise; repeat as necessary until you hi TOD (Top Of Descent).

[Jacques]

Dacamp66 is right on with his power setting procedure...MP then RPM then adjust the throttle to get the recommended PSI for the phase of flight. That would be for setting climb or cruise power down from takeoff settings.
When increasing power, its RPM then MP then adjust throttle for the recommended PSI.

You mention not having flown the 377 for a few months...so did you successfully fly above 10,000 ft in the past? And was the engineer managing the turbos or were you?

It is also useful to note that high altitude may not be the best altitude, especially for your outbound trip to "Mike". If you are using real weather or something like ASN, pay attention to the winds aloft map, as speeds can be quite strong on the nose going West across the Atlantic, and then very brisk on the tail going East, but you probably know that already!

Also remember that there is no critical need for the 377 to get to the higher altitudes as there is with a jetliner. The exception being winds aloft, weather or trying for a distance record! I think the 377 was only cleared to 25,000 (?) ft by the CAA.

[stretch1365]

Hi all and thanks for the replies,

I think last time I flew the B377 the flight engineer handles the turbo's just like now, I am not sure but most likely.

Yes I am using ASN and have come across high wind speeds over the Atlantic and North Sea, but yesterday I think they weren't anything approaching high.

I tried to do a return flight this morning from Tromso to Bruntingthorpe but this time with a light load and took off ok, got to 10000 quite quickly, which I would expect with a light load, and then had the flight engineer hold the climb MP at 46" and I adjusted the RPM. What I found was that if I kept the RPM at the 2500 setting as the notes said I got the same torque as yesterday, but if I reduced the RPM down toI think it was 1700RPM or maybe 2000RPM then the torque shot up to the recommended settings..................My test didn't get any further as fsx declared an unhandled error and shut down, which again is most unusual with my set up!

Anyway off to try again now!

[stretch1365]

Hi,

Just completed a flight from Tromso back to Bruntingthorpe, with a light load.

All went well and managed a cruise at 18000 ft and 214IAS, which I am more than happy with. What I did find though was that I had to alter the cruise/climb settings from those you see in the aircraft info page, depending on my altitude. I did find however that very minute changes in RPM would have an effect on airspeed, which was very interesting.

Anyway all sorted, thanks folks for your help.

[dacamp66]

stretch1365: NOTE: when adjusting power to compensate for altitude, pay attention to PSI, not MP.