4 COTS issues; Guppy, Turbos, Pressure, Joystick

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supercow18
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4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by supercow18 »

Hello,

This is my first post here but I just have to mention it. I absolutely adore the new COTS update, it really adds that 'extra-mile' to the product. There are so many new features I'me still discovering, it's a marvel. Alas, I have four issues. I do not know if these are meant to be or if they are bugs, which is why I dare ask.

Joystick:

1. I have the T.Flight HOTAS X Thrustmaster joystick with a single throttle but for some reason since installing COTS, the throttles barely respond. The throttles seem to skip on start up and I cannot start the engines without manually pushing the throttle levers. I can only take control of the throttle using the joystick once the engines are started but if I go down to Idle, it 'locks me out.' Basically, if I idle the joystick, the throttles idle too ans stop following the joysticks movement. Not until I use the mouse on the throttles to set them can I use the joystick again. I am not using the config utility nor FSUIPC.

Turbos:

2. Doing a manual turbo calibration has become some impossible as per manual. When I set the engine to environmental pressure (already quite difficult since the joystick seems to make it really sensitive) I then flip the turbo switch to climb + cruise but that is where things get awry. The MP readings get really high (substantially more than 2 inches above MP.) Forget about putting the lever to 7 - the turbos runaway and the engine is blown. Is this normal? Should I be turning on the Turbo bleeders (if they have an effect on the ground?)

3. Pressurization on descent is different. This may be normal behavior or something I am doing wrong, I don't know. Before starting the descent, I set the dial to the landing elevation and the rate of descent to about 300 fpm. As I am descending, I stop using the turbos by about 10k feet and this is where things become bizarre. The rate of descent shows an ascent and pressurizes the cabin to a higher altitude then what I had set it up for during cruise. I then turbo differential pressure. It takes quite a bit of turbos if I want to keep it working again. When the planes altitude equals the new cabin altitude, despite my descent rate, babies always start crying as I descend with a cabin rate of -1500 fpm!

Guppy:

4. I don't know if the new Guppies pressurization panel was intended to look like that or if I have a faulty install but I see the placeholder for the switches but there are no switches only the master. There are no more gauges either.

Thank You,
MJ

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Scott - A2A
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by Scott - A2A »

Supercow18,

1. I will defer this to “some1” who knows this area.
2. Yes, we altered the turbo lever to be more responsive down low, as this ended up giving a nicer, more realistic control using a game controller as opposed to moving the real lever with your hand. Just raise the turbo lever until you have some boost, 40” is enough, but no need to go higher than 50”.
3. There is a pressure relief valve to prevent a cabin vacuum condition (higher cabin alt than outside pressure alt). It sounds like you were pushing on this valve and not allowing enough time for the cabin pressure to get down. This is exactly what the real crews had to deal with too. Once you get used to it, you will plan your descents a little better, longer.
4. The Guppy has no pressurization so those gauges were removed to lighten up the aircraft.

Scott.
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lonewulf47
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by lonewulf47 »

Hi MJ,
May I step in here quickly to enlighten item 3 on your list. You mention that you "stop using turbos at 10k" - a very impressive statement however by no means compatible with an A/C with piston engines and pressurized cabin :lol: You simply cannot stop using the turbos - as those are needed to pressurize the cabin! As a result as soon as you stop using the turbos the cabin becomes unpressurized - of course not instantly but of the cabin rate indicator will show a climb until the A/C's altitude is reached. From then on it will "descend" with the A/C's descend rate as there is - as Scott pointed out already - a negative pressure relief valve which prevents the cabin pressure from being lower than the ambient pressure - a very uncomfortable state I can tell you from my personal experience. So as a conclusion: nothing really weird going on - all as it should be :wink: !

And to item 4: the Guppy has no turbos either apart from the geared blowers that will allow you to reach a take-off power boost of +54 in. as in the B377.
Oskar

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mattgn
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by mattgn »

To answer question number 1, increase your throttle null zone in FSX options by one click (I think it goes up in 5's).
Hopefully that should solve that issue.
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supercow18
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by supercow18 »

Thank you for the quick reply and clarification. It just goes to show how in-depth the upgrade has gone, absolutely awesome!

Yes the null zone fixed the joystick issue, thank you. Out of curiosity, what is the 'new' procedure for a turbo calibration? Since i dont have the 'ambient + 2 inches reference anymore its confusing me.

For item 3, ill plan my descents earlier from now on, i suppose the turbo lever has to be kept higher now all the way down to the approach where i can flip them back to takeoff and close the intercoolers. Makes for a hotter engine descent. The guppy has the labels and holes for the switches but no switches, which makes sense since its unpressurized, thank you for the clarification.

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lonewulf47
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by lonewulf47 »

Well, this is a Cabin Pressurization System simulation almost as real as it get's :lol: This is why the cabin Differential Pressure Gauges have been introduced. You must never reduce your turbo boost to allow the Cabin Diff Press reading lower than ~2 PSI. This is the minimum differential pressure required to fulfill the pressurization system's needs. I suggest that you let the FE handle the turbos and watch for his performance.

During initial climb you will see him throwing the Turbo Override Switches and the Turbo Bleeder Switches at around 500 AAL and then waiting another 500 ft to increase the turbo boost. You will notice an increase of your climb MP setting by a few inches that you have to counteract. the FE will always try to maintain a turbo setting that keeps the Differential Pressure at 2+ in.

Same happens during descent. Reduce power slowly and watch the Differential Pressure Gauges. At a certain setting you will notice that the FE is unable to maintain these 2 in. That's the moment when you reduced a bit too much. Just keeep the throttles at a setting where the FE can maintain enough boost for the cabin. That's how these old birds have been operating. There are no idle or other high-rate descents. It all has to be planned well in advance :lol: Aim for an average descent rate of 800 -1000 ft max. Plan for a continuous descent out of FL 300 taking some 35 to 40 min. thus covering a distance between 150 and 180 NM. Plan for a level off at final approach altitude inorder to bleed off the speed for gear and flaps. That's why you have become "Captain of the Ship" :wink: You got to master it - sooner or later.
Oskar

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Jigsaw
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by Jigsaw »

Thankfully it's easy to calculate and find a good top of descent with the Distance Travelled information and the ground speed calculation by the navigator. I don't even miss the DME equipment that the Stratocruiser doesn't have.
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by CAPFlyer »

supercow18 wrote:Out of curiosity, what is the 'new' procedure for a turbo calibration? Since i dont have the 'ambient + 2 inches reference anymore its confusing me.
It's actually the same as before. Set to ambient then increase the turbo selector lever until you get a 2" MAP increase and then trim the turbos.
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supercow18
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by supercow18 »

Well actually that's whats bugging me. When I do a turbo calibration, I'me on the ground, set each engine individually to environmental and set the lever to get a +2 per 1000 feet but therein lies the problem, there is no base reference. The manual states that you should set the lever to 7 and individually flip the climb switches when testing each engine on their own. With this 'old' way I could get an easy MP reference and trim the potentiometers to give me an even environmental +2. Now, if you place the lever on 7, the turbos run away.

Another thing is that the only time I get a back-pressure indication is when I flip the #1 turbo to climb and cruise. If I set 2, 3 and 4 individually, there is no back-pressure indication at all. It seems to me that turbo #1 has become a 'critical' turbo, which is obviously not how it was prior to the COTS upgrade.

So finally, one way I tried doing it is by placing all engines at environmental with the switches on TO, then placing every switch on climb. This is when the back-pressure increases on all turbos and I can play around with the calibration a bit. It's still not an accurate method though.... So what is the proper method?

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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by VulcanB2 »

@supercow18: there is some oddity on the systems programming (NOT COTS) where it seems you need all engines to be in the same state for certain things to happen. I have found for example the CHT is a bit strange until all 4 engines are started, then it seems to behave correctly. It is odd. Maybe what you are seeing too?

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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by Nico081 »

Questions to "ground test" proccedures checklist, page 86/87
Engineer

3. Place all four engine propeller
selector control switches in MAN
(manual) and hold each propeller
control switch in DECREASE
RPM until 1300 R.P.M. is
indicated (takes approximately 52
seconds per engine), then move
and hold each switch in
INCREASE RPM until 1500 is
indicated; then place the propeller
control switches in MAN
(manual)
-Twice setting "prop control switches" in MAN mode?
-When reducing to 1300RPM it needs seconds until RPM drops. After going back to 1500RPM do i have to stop pulling "prop control switch" exactly when reching 1500RPM or do i have to pull these "nothing happens"-seconds more, like before?
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by FAC257 »

Nico081

When you have cycled back to 1500RPM then switch the Prop Control Switch back to "Auto". That second reference to "Man" is a typo error.

You only need to cycle each prop one time, down to 1300RPM and then back up to 1500RPM.

FAC
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Nico081
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by Nico081 »

Thanks
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Re: 4 COTS issues; Guppy, Turbos, Pressure, Joystick

Post by FAC257 »

Thank you for spotting that. :)

FAC
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