Can't gain any altitude with heavy load?

BIG, double-deck, four-engine, medium to long range, high altitude, high speed, commercial transport airplane
Kalnon
Airman First Class
Posts: 61
Joined: 30 Jan 2022, 05:11

Can't gain any altitude with heavy load?

Post by Kalnon »

I'm new to flying the B377, I've only flown it a few times so far. The last time I tried flying it, I used the heavy pax and cargo preset to fully load the plane. I reduced the amount of fuel in the plane to make sure it was under MTOW but for some reason I can't gain any altitude, like the plane is overloaded. After take off, I slowly climb to a few thousand feet in the air and it gets to a point where it just won't climb any more and if I try, the plane will stall, even with the throttles maxed out. As I said, the weight was under MTOW but not by a lot. Do I have to reduce the weight some more or am I doing something wrong?

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Can't gain any altitude with heavy load?

Post by TreeTops »

Flying the B377 at max weight is like playing a game at highest difficulty; you really need to be able to coax everything out of the engines and use all of the Captain's knowledge of this plane to climb.
After liftoff and gear is retracted, reduce power to 50" MP and 2550 RPM. do not climb at anything more than 500 fpm until the flaps are retracted and the speed is over 170 knots.
Once you have reached this step you might be able to slightly increase your climb rate to between 500 and 1000 fpm, but do not let the speed drop below 170 knots.
To make all this happen, you will need to put the autopilot on and set it to climb at 500 fpm so you can devote all of your attention to the engines.
You will need to be very familiar with the take off procedure from the manual. A2A B337 Pilots_Manual_For_COTS.pdf pg91 and 94.
Are you switching the turbo override switches from Takeoff to Climb and Cruise?
(Note, don't be in a hurry to switch off the ADI pumps. According to pg 33 there is 8 minutes of supply so switch them off after 5-6 minutes once you have the plane climbing well.)
On pg 91 instruction No.6 you will notice there is a suggested climb setting of 50" MP, Max. torque 198 PSI and 2550 RPM.
On pg 94 instruction No.6 you will notice there is a suggested alternate climb setting of 46" MP, Max. torque 197 PSI and 2350 RPM.
(Note, 197 PSI is the main number to watch as it indicates you are achieving maximum power. Look at these gauges when you change either throttle or RPM. More MP or less RPM will result in more PSI.)
Important : As you climb the MP is going to reduce so increase power to maintain 197 PSI.
To maintain maximum power you will use a combination of throttle and turbo settings. Eventually the throttle will be wide open and then continue to add turbo.
You will need to watch the cabin airflow gauges (pg 42) to maintain at least 2" differential pressure using just enough turbo to stay between 2 and 3". Remember, changes in throttle/turbo affect both the engine PSI as well as the cabin diff. pressure so remember to check both gauges when changing either the throttle or turbo settings.
To reduce drag, try to slowly reduce cowl flaps as much as possible from takeoff setting of 3. You will need to watch the CHT like a hawk. Less drag will make for easier climbing.
Until you get more experience, only climb to 15-20,000 ft. If you get to these heights in less than an hour, give yourself a good pat on the back for a job well done.
If you find yourself getting slower than 160 knots, just level out and regain speed before climbing again. It is easy to become distracted by all the gauges and forget your speed.
There is some reading on pg 48 A2A B337 Accusim_COTS_Manual.pdf about using the automatic MP hold, but I find it best to keep manual control.
Once you reach cruise altitude, maintain climb power settings until the speed climbs to something like 200 knots before setting cruise power pg 98.

My suggestion is to begin at lighter weights and climb to 20,000 ft. Then progressively add another 5,000-10,000 lbs of weight each time.
If you find you are unable to devote 3-4 hours per flight, try just the climb portion and then quit once you reach 20,000.
Leave career mode off initially until you manage to achieve the climb with max. weight.
High cruise levels aren't the holy grail with piston engine planes like jets are. You will find there is only so high you can climb with a full load before you need to burn off a couple of hours of fuel to enable climbing higher.
Cheers
Trev

Kalnon
Airman First Class
Posts: 61
Joined: 30 Jan 2022, 05:11

Re: Can't gain any altitude with heavy load?

Post by Kalnon »

Wow, what a wealth of information there, thank you so much. I didn't realize how much there is to flying this plane properly. I have been reading through the manual slowly, there's so much to learn. I know I'll get the hang of it with the help of your instructions. The B377 is unlike anything I've ever flown before, I think I'm starting to fall in love :D

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Can't gain any altitude with heavy load?

Post by TreeTops »

I'm glad you are finding this plane interesting.

There are many threads in the forum about issues people have had in understanding what to do.
One of the more common ones is the Turbo Calibration setting of 7, found in the last section of pg 87. Here is a comprehensive explanation/experimentation and combined history of this issue.
viewtopic.php?f=80&t=69266&p=527039&hil ... on#p527039
Cheers
Trev

Kalnon
Airman First Class
Posts: 61
Joined: 30 Jan 2022, 05:11

Re: Can't gain any altitude with heavy load?

Post by Kalnon »

Thank you for that. I am finding this airplane extremely interesting. I've always been most fascinated with and love flying classic and vintage propeller airliners. I also have the A2A Constellation and a DC-4 by Flight Replicas, the Carenado Beech 18 and I even have a very nicely done Ford Tri Motor. These are FSX:SE planes. I also have a really great DC-3/C47 for X-Plane 11. I have to say though, I think the B377 I find the most interesting out of all of them. I only wish I would have bought it sooner. It was such a unique and complex aircraft for it's day. I want to learn everything about it now. I know I will be getting many hours of enjoyment out of this plane.

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Can't gain any altitude with heavy load?

Post by TreeTops »

Just wait until you start doing 4-10+ hour trips and only using the freeware sextant you can add for navigation/ :D
Cheers
Trev

Kalnon
Airman First Class
Posts: 61
Joined: 30 Jan 2022, 05:11

Re: Can't gain any altitude with heavy load?

Post by Kalnon »

You are probably right. I could see the long trips, I'm the kind of guy that spends much of my free time and even vacation time flight simming :D Right now for example, I am doing this really interesting cross country route by Transcontinental Air Transport (TAT) did back in the day that starts in New York and ends in San Francisco https://www.davidrumsey.com/luna/servle ... ute-of-Tra using the Ford Tri Motor, many of the legs are short but I do multiple legs at a time. Going all the way cross country U.S. in a plane that has a 110 mph cruise speed and has no autopilot, now that's my kind of way to relax :lol: I never have tried navigating by the stars. Would be an interesting challenge for sure. I think I might have to try that some time.

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Can't gain any altitude with heavy load?

Post by TreeTops »

Just search on this forum for sextant to get you set up.
Check this youtube channel for some nice flights. There are 2 with Tutorial - Bubble Sextant for you to look at.
https://www.youtube.com/channel/UCXdQ4p ... -jQ/videos
Cheers
Trev

Kalnon
Airman First Class
Posts: 61
Joined: 30 Jan 2022, 05:11

Re: Can't gain any altitude with heavy load?

Post by Kalnon »

Thanks again, I will definitely be looking into that. Back in the days of the space race astronauts had to learn to navigate in space by the stars in case the spacecraft navigation computer ever failed. The Apollo spacecraft actually had a special scope installed in it just for that purpose for view and navigating using stars. I'm also a big spaceflight nerd and I recently came across an amazing historical space flight simulator on Steam called Reentry https://store.steampowered.com/app/8821 ... Simulator/ where you can learn to fly the Mercury, Gemini and Apollo spacecraft as well as the Lunar Module and you can even recreate missions to the moon. I'm having a blast learning how to operate spacecraft just like real astronauts. I'm always looking for an interesting challenge, whether it's flying the B377 on a route with a full load or the Apollo CSM on a mission to land on the moon.

Hook
Master Sergeant
Posts: 1358
Joined: 31 Dec 2012, 01:38
Location: Bonham, Texas

Re: Can't gain any altitude with heavy load?

Post by Hook »

Flight plan, San Francisco to Honolulu (Stratocruiser or Connie)

Depart on a heading of 251 degrees true (237 magnetic) and turn 2 degrees south (left) every hour to follow a great circle route.

Optionally depart from San Francisco International Airport or Golden Gate Bridge. Departure heading will be the same.

2080 nautical miles, about 8 hours flight time.

Set real world weather but ignore winds aloft over the ocean. You wouldn't have accurate measurements anyway. You may prefer to have clear weather at Hawaii. :)

Set one VOR to Lihue in the north, the other to the main Island of Hawaii in the south. You will intercept one of these.

I have made this flight a few times in both aircraft, never missed the islands yet.

To fly the return flight, depart on a heading of 55 degrees true (46 degrees magnetic) and turn 2 degrees south (right) every hour.

No cheating! Do not use a GPS or the built-in A2A map. You'll be surprised at how close you come to your destination even with real world winds aloft.

Hook
Last edited by Hook on 16 Sep 2022, 15:18, edited 2 times in total.

Kalnon
Airman First Class
Posts: 61
Joined: 30 Jan 2022, 05:11

Re: Can't gain any altitude with heavy load?

Post by Kalnon »

I am totally going to try that :D

Hook
Master Sergeant
Posts: 1358
Joined: 31 Dec 2012, 01:38
Location: Bonham, Texas

Re: Can't gain any altitude with heavy load?

Post by Hook »

The 251 heading is true, measured in Google Earth.

I was just looking over my old flight plans and it says 237 degrees. This is the magnetic compass heading and is the heading to fly.

Good luck!

Hook
Last edited by Hook on 16 Sep 2022, 15:17, edited 1 time in total.

Hook
Master Sergeant
Posts: 1358
Joined: 31 Dec 2012, 01:38
Location: Bonham, Texas

Re: Can't gain any altitude with heavy load?

Post by Hook »

Ok, got it. I checked the flight plan on skyvector.com, and it turns out that 251 is true heading, 237 is magnetic heading. Fly 237 on the compass.

Above posts corrected.

Hook

Kalnon
Airman First Class
Posts: 61
Joined: 30 Jan 2022, 05:11

Re: Can't gain any altitude with heavy load?

Post by Kalnon »

Thanks for checking.

Kalnon
Airman First Class
Posts: 61
Joined: 30 Jan 2022, 05:11

Re: Can't gain any altitude with heavy load?

Post by Kalnon »

When I was playing FS2004 back in the day, I recreated the historic flight across the Atlantic in the Spirit of St. Louis since the plane was included with the sim. At the time, it was the longest flight I ever did. I did have to break the flight up into parts because I was working long hours at the time so I cheated a bit. I wish someone would create that airplane for a modern flight simulator so I can try that again :)
Last edited by Kalnon on 18 Sep 2022, 12:49, edited 2 times in total.

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