Parts the manual does not explain - navigator's station

BIG, double-deck, four-engine, medium to long range, high altitude, high speed, commercial transport airplane
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Styggron
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Re: Parts the manual does not explain - navigator's station

Post by Styggron »

TreeTops wrote: 01 Dec 2022, 05:35
Styggron wrote: 01 Dec 2022, 04:00 Yes I read your last sentence re the volt gauge but it does not give me enough information.
Does BAT mean the APU is still powering the plane? or is that BUS? I read over what you wrote multiple times....... hmmmmm

Also I still don't understand what the bottom 3 position switch on the APU does. Makes no sense to me at all. I need to find a clear explanation.
Yes up turns it on, yes middle turns it off..... and down engages the generator, ummm ok so I need to move it from top to bottom FAST because if you stop it at middle it turns off.

Ok so is there a reason you don't want to engage the generator ie why just have RUN??..... and what does engaging the generator do? (yes I know generators turn on and that does ummm errrrr...........) what does it do to the APU? or does the generators MEAN that when THEY are on, each of them gives power FROM the APU **to** engines 1,2,3 and 4........ is that right? It's not is it?
The APU switch is left click only. Click click click cycles through the 3 positions. There is no need to be fast.
The APU start position allows for the engine to start and warm up before applying the load of the generator.
The APP position engages the generator so now the engine is driving the generator which is supplying voltage to the main electrical bus. This is the position you need for the APU to be 'working'.
Each of the 4 engines when running also supply voltage to the main bus.
The engines are capable of starting off the battery but it is a huge drain and can quickly kill the battery. The APU however, happily supplies enough voltage to start the 4 engines and run the aircraft systems while you start up.
Once the engines are running, they supply voltage to the aircraft and the APU is no longer needed, so it can be shut down.

the BAT position on the dial means how many volts the battery is capable of supplying to the bus.
Thank you so much.
This is exactly the kind of thing I needed.

Excellent........ absolutely PERFECT..............
Thank you sooooooo much.

So the dial we have there does not transfer electricity to anywhere at all, it is only a selector to read the voltage on the meter coming from the position it is on the dial which you explained in a post above.
Yes?
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TreeTops
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Re: Parts the manual does not explain - navigator's station

Post by TreeTops »

Yes that is correct. It is only a voltage meter. During flight I leave it on Main Bus. As part of the half hourly checks I do during flight I rotate the dial to each position to make sure everything is ok.
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Trev

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Styggron
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Re: Parts the manual does not explain - navigator's station

Post by Styggron »

TreeTops wrote: 01 Dec 2022, 16:27 Yes that is correct. It is only a voltage meter. During flight I leave it on Main Bus. As part of the half hourly checks I do during flight I rotate the dial to each position to make sure everything is ok.
Thank you so much for all your help and patience.

I was also trying to find out more about the grown blower, there only main reference in the B377 manual (same one you have) is in the APU section.
I saw the Constellation also has a grown blower. I tried looking it up generally online but most references to it was always about Jet aircraft.

Could you perhaps give me some insight into the grown blower? What it does, why we have it, when you have to turn it on and when you should turn it off etc?

Thank you so much.
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TreeTops
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Re: Parts the manual does not explain - navigator's station

Post by TreeTops »

By grown blower, do you mean ground blower?

The ground blower for ventilating the cabin on the ground would need the APU running to supply power. It does not provide air conditioning, and for that you will need to run 3 engines (50% cooling) or 4 engines (100% cooling). It does however need to be running if the body heaters are on, to provide airflow past the heaters and through the cabin.

The blower mentioned in the APU section has nothing to do with the cabin cooling, but is a system in the APU bay just for ventilating exhaust fumes to prevent them from entering the passenger cabin.
Cheers
Trev

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Styggron
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Re: Parts the manual does not explain - navigator's station

Post by Styggron »

Hi Treetops

I was looking at another B377 tutorial and it contradicts what you say so now I am in the "ummmm so who is correct then?"

It is timestamped at the point they talk about the APU. So they say you put the dial to battery and that means the battery is giving power to the plane. This sis not make sense to me because they turned on the master switch and you could hear sounds BEFORE they turned that dial to BATT so...... yeah I don't know.

Then they said to feed power to the plane from the APU you need to put it on BUS
Reference is all here timestamped.

https://youtu.be/pBf0Fsr-Xhc?t=607

So now..... I don't know who is correct. :(
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TreeTops
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Re: Parts the manual does not explain - navigator's station

Post by TreeTops »

He may very well be correct, however there is a comment below the video which I will past here.
"my guestimate is that 'Voltage Selector' doesn't select source to system (BUS) but merely selects the source to show voltage of. The ON/OFF above it selects connect to the Bus. This is how its most common in modern aircraft also."

We do know that the electrical system for the B377 sim is a bit simplified, but you can do some tests. If everything is off (cold and dark) and the voltage selector is set to OFF, turn the cabin light on. Does it work? Does it work when the voltage selector is set to Battery?
Cheers
Trev

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Styggron
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Re: Parts the manual does not explain - navigator's station

Post by Styggron »

TreeTops wrote: 01 Dec 2022, 18:58 He may very well be correct, however there is a comment below the video which I will past here.
"my guestimate is that 'Voltage Selector' doesn't select source to system (BUS) but merely selects the source to show voltage of. The ON/OFF above it selects connect to the Bus. This is how its most common in modern aircraft also."

We do know that the electrical system for the B377 sim is a bit simplified, but you can do some tests. If everything is off (cold and dark) and the voltage selector is set to OFF, turn the cabin light on. Does it work? Does it work when the voltage selector is set to Battery?
sigh. see this is EXACTLY the kind of thing that should be in the manual!!!!!!
Either the video is correct or the person that wrote the comment is correct, so back to square one, we don't know (facepalm)

Regarding the test I already wrote above that you see them turn the master and avionics and that selector switch was on OFF but they still came on, he just puts it to BAT.
This either means it is NOT modelled correctly and simplified as you say or that the dial is just a selector. I don't see why trying to find out something like this is so hard.

I guess there are tons of people who don't know because, well, it is something that SHOULD have been in the manual. sigh.

Yes I did mean ground blower above, sorry.... typo.
Accufeel V2, C172 , B377+L049+COTS, B17G, Piper Cub,Commanche,Cherrokee,Spitfire,Bonanza, P47,P40,both Mustangs
Aircraft Factory Avro Anson, Albatros DIII,Heinkel He-219, F4U Corsair, P51H Mustang, Avro 504, BF109
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