The A2A Simulations Community

Hello,
I am having trouble getting the B377 to cruise at anything above FL 240, and my indicated airspeed wants to stay at around 220 or less. I am using the prop settings to have the engines running at 21000 rpm, with the auto lean feature set, all four turbo boosts turned on, and maximum throttle. What should I do to get the plane into the 300 mph range?
Thanks,
Jimbo 47

Jimbo,

220 IAS (Indicated Airspeed) is very fast, you are thinking TAS (True Airspeed). Look at your ground speed, as this is what the 300-350mph range you are looking to have.

Scott.

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A2A Simulations Inc.

Scott,
Thanks very much. I did look at the ground speed and you are right, it is getting into the low 300 mph range.

A ground speed of 265 knots is typical for this aircraft. The point to remember is that indicated airspeed drops off with altitude (compressability, colder temps and all that stuff) which is why mach number is more important than indicated airspeed above, say, 14,000 feet. Aircraft weight plays a big factor in all of this. This is important in all aircraft.

The manual recommends a torque cruise setting of 175 psi for most of the cruise settings. What that means is, manipulate the manifold pressure and prop rpm to get that torque value. At 14,000 with an aircraft weight of 120,000 pounds and a temperature of -10C and a mixure ratio of .75, I set the prop rpm at 1900, the manifold pressure at 40 inches to get an indicated airspeed of 205 which resulted in a ground speed of 265 knots. With 20,000 pounds of fuel the projected range was over 700 NM. This was a typical day and those settings are achievable.

This airplane uses around 19 pounds of fuel per mile at 265 knots GS which is not as good as a B737 which flies twice as fast and twice as high which is why the airlines that flew stratocruisers didn't waste any time getting rid of them when jets came along. If you imagine the cost of fuel is coming out of your own pocket rather than some infinite cost-free adventure, you will find yourself being a lot more cautious about beating up the engines on climb power when you should be worrying about fuel and maintenance costs. Remember these airplanes used 100/115 or 115/145 aviation gasoline in the 1950's which cost about $.45 a gallon and required 3 hours of maintenance for every 1 hour of engine time. You can't buy that stuff now and 100LL avgas it over $6.00 a gallon these days. I am still learning the best fuel load to put on, many times I take more fuel than I need. Every pound of weight (fuel) you didn't need to carry costs money to take along for the ride. Maxing out the fuel load means extra takeoff distance, and it takes longer to get to altitude which is harder on the engines. Crashing on takeoff is no fun, and stalling the airplane at 24,000 feet because it is too heavy is no fun either!


The longer the engines are struggling along on climb power, the harder it is on them. Level off and cruise for a while to stabilize the temps and then climb some more later when the airplane is lighter.

[*]Agreed, great points.
I fly with just as much fuel as I need always allowing for the obvious alternate.
In 1950 fuel and repairs were cheap by todays rates but in 1950 the bean counters still looked at these numbers very closely.

I am not a real world pilot but over the coarse of near 1000 hours on the only plane I fly I have found that using a 5 degree nose up on climb provides the best climb rate.
One would think that If the nose is at let say 10 degree up it would get to your set cruise altitude faster, Wrong.
Its much harder on those temperamental engines, and your fuel cost will simply go through the roof.
Get the nose too far up and you're pushing rather than lifting.
I fly at no more than FL 24, I don't think this aircraft was flown at much higher attitudes.
I have read stories that descents could be at very steep angles to make up for the very expensive assents.
Cold weather exceptions/operations ( Arctic) to this rule were very slow graduated step descents to prevent temperature shocking of the engines ( radical temperature variations ) which created very expensive premature failures and/or repairs.

Raebo,

It's really not optimal to target a deck angle in the climb, as you are doing. Target a speed and a power setting is the way to do it instead. Go for ~187 psi of torque and 2350 rpm, which should occur around 46" MAP, and adjust your pitch to maintain 170 knots. (You can also use the Notepad settings as well, which I think are 2550, 198 lbs, and max 51".) In either case, you'll still want to shoot for a climb speed. I don't think anybody actually knows the Vx and Vy numbers for this airplane precisely, but 160 kts is a good guess for Vx and 170 is a good guess for Vy, your best rate of climb. Stick to the 170 knots for an economy climb and you will be operating the simulated aircraft very close to how the real thing was flown.
For cruise, plan on 2100rpm,158 torque and adjust those numbers to get about 185 knots indicated. You should see just under 1000 lbs/hour from each engine during cruise in Auto Lean.

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While there are problems with the specifics of his post (use the A2A manual for all power settings), I always suggest the FSAviator propliner tutorial for people wanting to know how to fly a classic propliner.

www.calclassic.com/propliner_tutorial.htm

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Lots of good information here. What it boils to in my opinion, is how expensive (sic) and real do you want this to be?

Unlike modern airplanes you can't put the Stratocruiser on autopilot and go have a beer while it navigates itself. It has to be handled full time! It doesn't land like modern jets since it doesn't have leading edge flaps/slats and it has fat, soft big rubber tires. Handling the engines is much more complicated than jets and without proper care, you can run yourself out of gas or oil even if it is loaded to the gunwales with liquid energy.

Which is why we love it.

I find it is best to let her cruise climb. Get her trimmed out for desired cruise speed at e.g. FL250, and as she burns fuel she will gently climb. You should be able to make FL250 under most conditions, but you will need patience, and the correct climb speed. I climb at 165 kts IAS and trim for this.

Best regards,
Robin.

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A2A/AccuSim. 'nuff said!