A2A Stratocruiser

[cormack]

hi! I've tried to apply your flying tips for A2A Stratocruiser and I have several questions.

1. I'm flying from San Francisco to Honolulu with nearly maximum load and strong headwinds and I was able to get to FL200 without any problem, in about 1hr30mins. Doesn't it seem very excessive?
2. I am not sure if I am doing the step climb right, am I to keep the cruise MAP and RPM after reaching 185 KIAS or revert back to MAP and RPM suggested for climb phase 2 or something else?
3. Setting cruise RPM and MAP seems excessive brcause even with strong headwind it takes about 10 minutes to get to 185 KIAS from 165 KIAS. Note that I can do this while being as heavy as 137.000 lbs. 

Is this realistic? From what I've read it should take many hours to get to FL200, not 1hr30mins. 

[Tom/CalClassic]

Hi,

1. Yes that does seem a bit excessive, but keep in mind that the Strats often stayed lower on westbound flights to stay out of the greater headwinds often present at higher altitudes. And keep in mind that just because you *can* climb to FL200 that may not be the most efficient cruise altitude for your weight. If after going to cruise power your attitude is more than a little nose up you are flying too high.

2. There are two ways to do step climbs - a normal climb and a cruise climb. When under ATC control in busy areas, you normal climbed - increase MAP and RPM to normal climb values and climb at a minimum of 500 fpm. If over the ocean or in remote locations, you could cruise climb instead (if under ATC you would need permission as well). Maintain your current cruise MAP and RPM settings, and climb only as rapidly as would allow you to maintain minimum climb speed. This was often 100 to 200 fpm or so.

3. I'm not sure what you mean by this?

Hope this helps,

[cormack]

Apr 27, 2016 12:16:01 GMT -5 Tom/CalClassic said:

Hi,

1. Yes that does seem a bit excessive, but keep in mind that the Strats often stayed lower on westbound flights to stay out of the greater headwinds often present at higher altitudes. And keep in mind that just because you *can* climb to FL200 that may not be the most efficient cruise altitude for your weight. If after going to cruise power your attitude is more than a little nose up you are flying too high.

2. There are two ways to do step climbs - a normal climb and a cruise climb. When under ATC control in busy areas, you normal climbed - increase MAP and RPM to normal climb values and climb at a minimum of 500 fpm. If over the ocean or in remote locations, you could cruise climb instead (if under ATC you would need permission as well). Maintain your current cruise MAP and RPM settings, and climb only as rapidly as would allow you to maintain minimum climb speed. This was often 100 to 200 fpm or so.

3. I'm not sure what you mean by this?

Hope this helps,

1. I've read that I am supposed to go higher by 2000 feet when my KIAS is 185 and it was so very shortly after setting cruise altitude. How am I to see that I am at wrong altitude for my weight except for slow acceleration in KIAS?
3. I mean that even though my plane is quite heavy and I have pretty strong headwind, my plane still accelerates awfully fast, which seems unrealistic. My question is - am I right that it is unrewlistic? I've read that it might take many hours for the plane to be able to fly fast on pretty high altitudes such as FL200 but in A2A plane it seems to be taking about 10 minutes to get to 185 KIAS from 165 or so under conditions as I've described them.

[Tom/CalClassic]

Hi,

Ah, OK. You use the plane's attitude to determine if you are at the right altitude for the current weight during cruise. If the attitude indicator's tool tip does not give you a value, go outside the plane and compare the plane's attitude to the horizon. If too nose up, you are too high.

3. I have very little flight information about the Stratocruiser, unfortunately. In our handling notes, it says to step climb if you exceed 190 KIAS.

[cormack]

Also, quote from FSAviator

If our OC ever reaches B377 certification ceiling in today's weather the same fuel burn now yields much higher velocity (264 KTAS) in thinner air, at lower weight, at reduced and more profitable profile drag (180 KIAS). The handling notes illuminate the fact that in average weather our OPERATIONAL CEILING will not equal our CERTIFICATION CEILING until our weight has fallen to 124,000 pounds.

----------

In A2A Stratocruiser I have no trouble reaching and accelerating quickly at FL250'with 129.000 pounds but with tailwind of 40 kts. Is it because of the tailwinds?

[cormack]

Apr 27, 2016 13:46:14 GMT -5 Tom/CalClassic said:

Hi,

Ah, OK. You use the plane's attitude to determine if you are at the right altitude for the current weight during cruise. If the attitude indicator's tool tip does not give you a value, go outside the plane and compare the plane's attitude to the horizon. If too nose up, you are too high.

3. I have very little flight information about the Stratocruiser, unfortunately. In our handling notes, it says to step climb if you exceed 190 KIAS.

At the moment when I've decided to climb higher, my attitude indicator showed not even a single pitch up or down. After climbing it showed about 1 or 2. 

[awralls]

Headwind doesn't affect your acceleration in terms of IAS if that's what you're judging it by. Obviously, it affects your ground speed, but that's not an indicator of aircraft performance.

Andy

[cormack]

I've just made another experiment and with maximum permittable weight on start I was able to easily climb to FL160 in 37 minutes and i was with 140.700 lbs of weight while doing so (36.900 lbs of fuel alone). My attitude indicator showed 3 degrees up and dropped to 2 degrees after about 2 minutes. All in all, in about 5 minutes I was able to reach 180 KIAS and 1 degree up pitch. And about 7 minutes after, 185 KIAS and no degree either way. After waiting another minute, it reached 189 KIAS.

Correct me if I'm doing something wrong. During cruise I am holding 38 in MAP and 1700 RPM, while for climb I am changing it to 45 MAP and 2350 MAP, rejecting climb before KIAS reaches 165 KIAS, as was stated in the handling notes from Cal Classic site.

At 140.200 lbs of weight I have began my second altitude change to FL180 and reached it after 49 minutes since I've departed. I was flying at 164 KIAS upon reaching FL180. This raised to KIAS 173 in about 3 minutes. After 6 minutes since altitude at FL180 hold I reached 186 KIAS. My weight was 139.500 lbs, fuel 15.760 lbs. Not a single degree in pitch.

As to weather conditions I had headwind of about 11 kts and right Xwind of about 62 kts. Mag. Heading 245.


I am still in flight and I'll note more information about it. Mainly how long it would take now to get to FL240.

[cormack]

I reached FL200 after 59 minutes, weight 139.000 lbs, fuel 35.280 lbs, at the moment of setting altitude hold I had 163 KIAS. After about 2 minutes I had 170 KIAS. Pitch 2 degrees up after 2 minutes. "Live engineer" AI set turbos to 61%.

4 minutes later - 180 KIAS, not a single degree pitch either way. I've noticed that I was setting MAP to 35,5 - 36 in, not 38 all the time. I will set it to 38 in from now on.

Anyway, after 1hr5mins I've reached 192 KIAS and began transition to FL220. Reached it 1 hr 9 or 10 mins from the start. Pitch 2 degrees up, weight 138.100 lbs, fuel 34.330 lbs. Turbos at 67 percent, turbo temp - 122 degrees celcius.

Reached 185 KIAS after 1hr 13 mins since the start. 190 KIAS a minute later. Turbos were still at 67%.

After 190 KIAS I began to change my altitude to FL240, I won't go any higher. Stopped at FL230 as my KIAS dropped to 167. Reached FL230 at 1hr 17 mins since the start.

Then again, I reached KIAS 190 at 1 hr 20 mins since the start and started to move to FL240. I reached FL240 at 1 hr 23 minutes from the start. My weight was 136.900 lbs, fuel 33260 lbs. Distance traveled - 320 nm, attitude indicator showed not a single degree, free air temp -25 degrees celcius, turbo at 74%, turbo temp - 104 degrees, engine temp 201 degrees. At 1700 RPM and about 36 MAP I am able to maintain speed of about 180 KIAS.

Doesn't it seem excessive that I managed to get to FL240 in as little as 1 hr and 23 minutes, when in real life it was supposed to take hours?

[awralls]

What happens if you try it with the CC/Greg Pepper B377?

[cormack]

I'll make an experiment with it later, for now I just wanted to post it so pilots who know better than me could check it.

[Tom/CalClassic]

Hi,

You cannot mix and match aircraft with different flight dynamics and expect perfection - the A2A aircraft was not designed to use our handling notes. Yes, in an ideal world that would be the case, but FS flight dynamics are not very accurate (i.e. they do not have many data points in their performance tables) and thus some compromises must be made. It appears that A2A and FSAviator made different compromises. But different airlines flew the plane quite differently, making variations in flying techniques quite realistic.

The other possibility is that A2A made the plane somewhat easier to fly than did FSAviator, since it is payware and they wanted people to be able to fly it so they would have reasonable sales?

OK I have done a bit of research, and the A2A plane comes with a full flight manual:

www.a2asimulations.com/Products/FSX/B377/Stratocruiser_Pilots_Manual.zip

It says that a typical climb power (46" MAP, 2350 RPM) will allow climb to 30,000 ft at 142,000 lbs in 67 minutes.

It also says that for cruise at 135,000 lbs at 25,000 ft you use 37" MAP and 2350 RPM, which should yield 190 KIAS.

So you should be flying using those numbers, not ours.

Hope this helps,

[cormack]

I see, thanks for pointing out that A2A Stratocruiser has to be handled differently from the FSAviator one.

What really bothers me, does that mean that A2A Stratocruiser is less realistic than FSAviator's one? It certainly seems that A2A one is horribly too easy to be flown and one could practically ignore the necessity of step climbing.

Also, aren't FSAviator's handling notes based on the real life ones? I mean, he surely based them on something and A2A must have based theirs on something too, and the outcome just seems not right - these planes seem to be ENTIRELY different in many crucial aspects and their handling notes are different too, the A2A ones sounding much less professional in my opinion.

In comparison, I'd say that FSAviator's plane seems to be closer to reality in the outcome of the flight. Or perhaps I am doing something wrong? What about the auto lean for example, I am setting it when I am at FL240, perhaps that's my mistake? I don't have enough knowledge now, I guess, perhaps you can help me by analysing the information I gave you above to see if I'm doing something incorrectly. It is really hard to believe that these planes could be so dissimillar despite being based on the same model.

[Defender]

Hi,

Have you downloaded all these?

a2asimulations.com/forum/viewtopic.php?f=37&t=11267&start=15

Go to the May 25 post and the dropbox.com links. The May 14 and enginehistory.org doesn't work.

You might find that Boeing data useful. By the way, I recall that the engine power table in that forum post might be inaccurate. It might have confused BMEP and torque which have about a 5% differential in the R4360.

It seems the B377 could indeed get straight to 20,000' + at high weights if and when there was any need to. The military appear to have used METO for the entire climb but commercial operators probably used lower settings. These charts use options of 2,650 BHP (2,550 rpm/198 torque/189 BMEP) and 2,240 (2,550 rpm/168 torque/159 BMEP).   

Bill 

[cormack]

I'm downloading more and more materials but I haven't read them all yet. In the accident reports I've seen, all PAA - Brazil one and two Hawaii ones, altitudes were changed very slowly. For example, Stratocruiser which succesfully ditched in 1956, never flown higher than FL210 and climbed to FL210 from FL130 after about 5 hours and another one, lost in 1952, flew following levels - FL125, FL145, and then finally FL185 (and this all spanning 11 hours). All other PAA flights about which I've read, were also conducted on pretty low altitudes for mozt of the time, and I can't recall any that would have reached maximum operational ceiling.

I just think that they would have flown higher if it was that simple.