|
Post by Tom/CalClassic on Apr 28, 2016 13:47:36 GMT -5
Hi,
There is speed, and then there is economy. While flying higher allowed you to fly faster, in propliners flying lower often allowed you to fly more economically. Considering the high operating cost of the Stratocruiser to start with, it is not surprising that they often flew it lower and slower, so the airline might actually make some money.
|
|
|
Post by dave mcqueen on Apr 29, 2016 4:05:23 GMT -5
Hi, ............... If over the ocean or in remote locations, you could cruise climb instead (if under ATC you would need permission as well)............... Hope this helps, I had a number of conversations with controllers who were working the oceanic positions in the 1950s. They told me that at that time their job was to provide flight following and initiate search and rescue if needed. They did not excercise positive control over oceanic flights so permission was not required for an aircraft to change altitude or course. Traffic advisories were issued if available but the pilot had the last word. When that all changed I'm not sure- probably after jets came on the scene- but the Oakland ARTCC oceanic areas were all positive control airspace before 1969. Even into the late 70s though IFR flight plans into oceanic airspace contained notations like TOD - top of descent - alerting a control agency when a flight would begin its descent. In the Tahiti Center airspace aircraft landing at Papeete would report top of descent and then start down with no ATC clearance issued. There was very little traffic down there.
|
|
|
Post by Tom/CalClassic on Apr 29, 2016 9:22:49 GMT -5
Thanks for the details, Dave. I know the flying boats routinely cruise climbed, but I don't know how common it was in later years.
|
|
|
Post by cormack on Apr 30, 2016 6:16:17 GMT -5
I see, thank you for your responses!
I asked the same question on the A2A forum, to see how they would respond, and their answer was that while the Stratocruiser was certainly capable of climbing as fast as I've described it, its engines were babied by keeping them low. Is that correct? FSAviator describes the Operational Ceiling and how to judge it and how to achieve it. Where could he get information about it from? If from real-world material, how come is it so different?
Also, does anyone here possess or know the real-world PAA procedures and handling notes? I'd love to fly the Stratocruiser as realistically as possible, but it's sometimes very hard to find any information about some things. For instance, I have no idea how strong headwind would justify flying at, let's say 10.000 feet, what kind of power setting I am supposed to use as PAA Stratocruiser captain, and how am I supposed to match the timetable of 8 hrs 45 mins from San Francisco to Honolulu while flying that low.
|
|
|
Post by Tom/CalClassic on Apr 30, 2016 9:50:24 GMT -5
Hi,
I have never found a really complete flight manual available, unfortunately.
The operational ceiling is simply the altitude that allows the most efficient cruise at the current weight using the desired cruise power. Often this is determined by the plane's attitude. We determine this by actual testing in FS, if we don't have this info in a flight manual.
Winds aloft are a tricky thing to determine in FS. I usually use the wind report gauge (FS9 only) and then fine tune that by maximizing my ground speed using the GPS (my virtual navigator) as I step climb. When my ground speed goes down after a step climb, I go back down for a half hour or so, then try again.
|
|
|
Post by Defender on Apr 30, 2016 10:33:42 GMT -5
Cormack,
I'm not sure I understand your interest in how high and fast it will go, neither of which was really relevant in real life operation. As long ago as 1949, BOAC used 1,750 bhp cruise power, that's 2,100 rpm/159 psi torque or 2,200 rpm/152 psi - use torque, not MAP, to set your cruise power. There were expectations of having the aircraft eventually cleared for 1,900 bhp operation but it turned out that it required an uneconomical and range compromising autorich mixture, possibly an engine cooling issue, and so it seems that 1,750 bhp, or 1,735 bhp continued in use. At that cruise power the Stratocruiser would have to be down to about 130,000 lbs before cruising above 20,000', maybe 15,000' at 140,000 lbs. Of course it could still climb higher, but unable to use that weak mixture cruise power.
I'm afraid there may be no simple answer to your "real world PAA procedures" request. It would vary according to the route, the weather conditions and the payload booked. So on a BOAC westbound London-New York service, it might fuel stop at Keflavik and Gander, in which case it would have a much lighter fuel load, so good payload capacity, each sector and normal cruise power would get it along fairly quickly. Or if conditions were right, it might attempt a non-stop using long range cruise settings. Apparently a BOAC aircraft once did this at 4,000' to 6,000' the whole way taking 16 hours which was probably not much quicker than the two fuel stop option! There are long range charts in the link I gave you earlier. If you are really interested then you might have to invest in the real world flight manuals, as I have for all my favourite aircraft. There's a good version available here,
www.ebay.nl/itm/BOEING-377-STRATOCRUISER-AND-KC-97G-5-FLIGHT-MANUALS-/140304404867?hash=item20aacb5183
I've used this source several times and no problems. That KC-97 manual includes power and performance charts and also discusses cruise technique is some detail including a table setting out the comparative trip times and fuel requirements for a typical 2,000nm flight. The options it gives are,
- long range cruise at various fixed altitudes
- long range cruise with two steps, 8,000' and 16,000'
- long range cruise with three steps, 8,000', 14,000' and 20,000'
- constant power cruise
- constant speed cruise
Least fuel but longest time was LR cruise at 5,000'. Shortest time but highest fuel was LR cruise at 15,000'. The best fuel/time compromise was the three step LR cruise.
It's also got BOAC and United pilot's notes. Be warned however that the more time you spend researching, the less time you have to enjoy flight sim!
Bill
|
|
|
Post by jimmyfingers on Apr 30, 2016 19:42:22 GMT -5
All the responses are right on target. FSAviator does a very thorough job describing the difference between jets and props. For a jet, it is CRITICAL to get to altitude as fast as possible, where fuel efficiency is optimum. For a prop, fuel burn is constant no matter the altitude. So screaming up to some high altitude at max climb power does not help. In fact, as several have pointed out, taking care of the engines was extremely important for commercial operators. The Air Force could afford to beat the engines to death at METO for 30 minutes. They could easily wait a couple of days for an engine change. Pan Am or BOAC could not. I fly the A2A 377 quite a bit and I typically climb at 41"/2350 or about 175-180 BMEP. I set cruise power at 155-150 BMEP, then super lean and can maintain 180-190 KIAS for about 3200 to 3400 PPH. I have tried climbing at higher MAP but the FE seems to keep chirping that the engines are a little warm. (I tell him to crack the cowl flaps a little more and adjust the inter coolers but I am ignored. ;-)). I wil note that I rarely fly at a GWT over 120.000 lbs or so, so I can get away with the lower climb power. The other mention that is important to note is "the weather" and all that that implies. Wind was not the only concern; icing, particularly in the higher latitudes, was an important consideration. While the Strat had thermal AI for the wings and electric props, flying in icing for any length of time was probably not the best idea. Bill can probably add some more to that statement. The last thing on weather was pressure pattern flight planning. There were no "tracks" as there are today. The flight was planned to keep headwind impact a minimum and to take advantage of tailwind. So, depending on the weather systems, the fight plan could make several bends that you would never see in a jet track.
|
|
|
Post by romanasul on May 2, 2016 22:24:24 GMT -5
I'm not sure if this has been posted before but here is a link for old school performance charts for the 377 stratocruiser from the A2A forums. There is also a chart that helps convert BHP from BMEP and RPM values: a2asimulations.com/forum/viewtopic.php?f=37&t=23994
|
|
|
Post by Defender on May 3, 2016 4:05:53 GMT -5
Thanks but see my post 28 April. The engine power chart is not accurate.
The torque calculation (for that engine) is BHP x 190.84 divided by rpm.
The BMEP calculation is BHP x 181.53 divided by rpm.
So the Engine History article gives 158 torque, 150 BMEP for normal cruise 2,100 rpm, 1,735 bhp.
I think the A2A version's panel shows torque, not BMEP, but you might check. They are easily confused.
Bill
|
|
|
Post by Dan on May 3, 2016 10:06:15 GMT -5
Although not exactly what are you need, but maybe you'll also find some useful info in the Boeing Stratocruiser Pilot's Handbook (1949) en.bookfi.net/book/614709
|
|
|
Post by jimmyfingers on May 4, 2016 6:49:19 GMT -5
Great find, although my Russian is a little rusty (JK). Interesting that AOA referred to the engineer as the "Auxiliary Operator". I think I like Flight Engineer better.
|
|
|
Post by Dan on May 4, 2016 13:41:33 GMT -5
Aha, and how about Airplane commander (today's Pilot) and Pilot (currently CoPilot) on B-29?
|
|
|
Post by cormack on May 6, 2016 21:45:51 GMT -5
Does anyone know where I could find PAA manual?
|
|
|
Post by Defender on May 7, 2016 14:10:58 GMT -5
I doubt there is one available online but exactly what information are you looking for?
Bill
|
|
|
Post by cormack on May 7, 2016 21:12:10 GMT -5
I am looking for company procedures: - How to execute climb (when the pitch is zero and 185-190 KIAS or differently) - To step climb or to climb continuously - How fast should I descend - How should I navigate
Or if those are not possible to obtain, how was it customary to do those things with B-377.
|
|