Manifold Pressure Selector Question

A Living Legend
Tom347
Airman
Posts: 24
Joined: 19 Nov 2017, 06:20

Manifold Pressure Selector Question

Post by Tom347 »

I'm new to the B-17, and I think it's awesome, by the way.

As I understand it, the typical way to fly it is to set the throttles full and control power via the knob on the selector.

This doesn't seem to work well for me, with the throttles full, I need to dial the knob back to almost 0 most of the time.

For example, in cruise the manual says to set it to 4-5. When I do this I need to point the nose down and get pretty high air speeds to keep from climbing; I feel like I'm constantly fighting the plane. Also, I had the plane up to 18K ft and just could not descend.

Anyways, what's the secret?

Thanks in advance.

User avatar
Jacques
Senior Master Sergeant
Posts: 2376
Joined: 26 Jun 2011, 17:54
Location: West Coast, USA

Manifold Pressure Selector Question

Post by Jacques »

Hi Tom,

That doesn't sound right at all. But you need to give a bit more information before people can start jumping in with ideas and suggestions!

First, which platform are you using? FSX, FSX-Steam or P3D version?

Second, have you run the all in one updater for all A2A aircraft?

Third, might be more obvious but I'll ask any way...do you have the base pack and the accusim pack for the B-17?

Sent from my iPad using Tapatalk

alan CXA651
Senior Master Sergeant
Posts: 2438
Joined: 15 Mar 2016, 08:23

Re: Manifold Pressure Selector Question

Post by alan CXA651 »

Hi Tom.
Extra to what Jacques has said , how are your controls set up , in FSX/P3D or through FSUIPC , i have mine going through FSUIPC and some through the A2A control configurator , also when jacques mentioned P3D it works fully in P3Dv3 but only non accusim version works in P3Dv4 and it was made for FSXA and FSX steam so if used in P3D v3 or 4 its at your own risk , with mixed results .
I am a member of the 91st bombardment group and the A2A B17 is our main aircraft , which is much modified , with a norden bombsight , extra views , gun and bailout mod extra nav equipment , and a puka module , that can damage your B17 when in flak , i also have the vac mod installed , so if eng 3 goes down i have to change the vac source to eng 2 , else gyro stops working.
regards vCol Alan(a dale) cottrill CO 324th BS flying the "Memphisbelle"
8)
Image
Image
Image
Image

Tom347
Airman
Posts: 24
Joined: 19 Nov 2017, 06:20

Re: Manifold Pressure Selector Question

Post by Tom347 »

Ah, sorry, I should have included more info. I actually am suspecting its more the way I'm flying it an not my setup. but here's what I got.

FSX, SP2. Saitek yoke with extra throttle quad. Using my MS joystick currently for rudder (new pedals coming today, yeah!). I've got the slider on the joystick programmed for the MPS knob via the software that came with the B-17.

It is the accusim version of the B-17.

I'm not sure what the "all in one updater" is, but I've just purchased the B-17 a few days ago, so I assume its the latest.

Thanks for the quick responses.

(Also, Alan, I've just applied at the 91st. I'm interested, but I'm not sure I have the time. But I'd like more info)

User avatar
Oracle427
Chief Master Sergeant
Posts: 3916
Joined: 02 Sep 2013, 19:30
Location: 3N6
Contact:

Re: Manifold Pressure Selector Question

Post by Oracle427 »

You need to download and apply the update from the sticky topic above. The base package has no updates.
Flight Simmer since 1983. PP ASEL IR Tailwheel
N28021 1979 Super Viking 17-30A

Tom347
Airman
Posts: 24
Joined: 19 Nov 2017, 06:20

Re: Manifold Pressure Selector Question

Post by Tom347 »

OK, I've run the updater and it said I was at version 1.0 and it upgraded to 1.30.

I won't be able to try it until later today. At which time I'll update this thread with the results.

Thanks again for the help.

alan CXA651
Senior Master Sergeant
Posts: 2438
Joined: 15 Mar 2016, 08:23

Re: Manifold Pressure Selector Question

Post by alan CXA651 »

Hi Tom.
I hope you like the new rudder peddles , it makes one hell of a difference to your flying , but will take a little getting used to for coordinated turns , but just keep practicing , its worth it.
Has for joining the 91st , on the hops , it is done at your pace , and allows you to get used to the B17 , and after phase 3 you get to fly your chosen paint in your squadron , some of the bomb runs are short but the berlin runs are 9 hrs in formation on joinFS and TS3 for coms , and on my berlin runs i was severly damaged by flak and limped home on 3 engines , with severe vibrations , on one occastion landed with eng 3 and right gear shot away , and shut eng 4 down on short finals to prevent any damage to it and with flaps up , it sure as hell gets the concentration levels up on them flights.
I hope you like flying with the 91st , if you need any help , then let me know.
regards alan. 8)
Image
Image
Image
Image

Tom347
Airman
Posts: 24
Joined: 19 Nov 2017, 06:20

Re: Manifold Pressure Selector Question

Post by Tom347 »

Ok, so the updates helped a lot on take off climb out, and cruise. But I still have a bear of time descending. I've been practicing by climbing and establishing level flight at 11,000 ft. Then trying to descend.

I set the pressure knob really low 1 or 0, but descent is in the order of 100 ft/min. From 11,000 feet, that will take a while. Anything below 3 and my flight engineer (or copilot?) keeps telling me my carb temps are getting too low.

I can descend if I drop the knob to 3 and throttle back to get down to 20-25" and set the RPM to around 1700 or so. Then I descend nicely. Is this OK?

I don't get complaints from crew and no damage to the engines once on the ground, but I thought one was supposed to fly mostly at full throttle and just use the knob.

Any help with procedures on descending would be appreciated. (there's no help in any of the manuals or anything I can find on the net about descending in a B-17. ??)

User avatar
Jacques
Senior Master Sergeant
Posts: 2376
Joined: 26 Jun 2011, 17:54
Location: West Coast, USA

Re: Manifold Pressure Selector Question

Post by Jacques »

Hi Tom, here's what I have in my notes:
Descent: Turbo set at "8" for 100 octane, or "7" for lower octane.
Mixture is auto rich
Pull back throttles as necessary to maintain 25" MP and 2000 RPM or LESS.
Fuel boost pumps on
Reset altimeter below 18000
Oxy off below 12000
Carb air filters on below 8000.

This has always worked well for me, as long as you are constantly reducing your throttles to keep MP at 25". Leaving the Turbo set at 8 eliminates the carb icing.


Sent from my iPad using Tapatalk

Tom347
Airman
Posts: 24
Joined: 19 Nov 2017, 06:20

Re: Manifold Pressure Selector Question

Post by Tom347 »

Thanks, that's close to what I'm doing. Except leaving the knob at 8; which I saw in the manual & check list but it says that's for "approach". (Descent from high altitude doesn't seem like approach to me, so I wasn't sure if I should be doing that or not.)

Plus I keep reading statements such as "real B-17 pilots fly at full throttle and just use the MP knob".

So I'm confused, but as long as I'm not doing anything exotic, and am doing about what others are doing I feel OK about it.

Thanks. I'll continue flying that way.

alan CXA651
Senior Master Sergeant
Posts: 2438
Joined: 15 Mar 2016, 08:23

Re: Manifold Pressure Selector Question

Post by alan CXA651 »

Hi Tom.
When on missions in the 91st we are sometimes at 23000ft and start the decent on our way back at about the coast of europe heading for UKBA , the decent is about 500fpm 8 on boost setting speed about 200mph , this normally keeps the carb temps warm enough to stop crew complaints oxy off at 10000 and filters on at 8000 .
If you need any help then feel free to get on ts3 if you see any 91st members on there , the red R symbol means they are instructors , and we will be happy to fly with you .
regards alan. 8)
Image
Image
Image
Image

razark
Airman Basic
Posts: 8
Joined: 24 Jun 2016, 21:06
Location: Houston, TX

Re: Manifold Pressure Selector Question

Post by razark »

Tom347 wrote:Plus I keep reading statements such as "real B-17 pilots fly at full throttle and just use the MP knob".
If it makes you feel any better, I remember seeing a WWII training video on the B-17. Carb icing was specifically mentioned as a problem, and the solution was increase turbo and decrease throttle, so you're doing exactly what you're supposed to.
ImageImage

Tom347
Airman
Posts: 24
Joined: 19 Nov 2017, 06:20

Re: Manifold Pressure Selector Question

Post by Tom347 »

Sounds like I'm doing pretty close to correct. I just misunderstood what was correct.

Thanks for all the help. I'll continue practicing.


Now if I could only make a normal landing instead of a controlled crash. :wink:

alan CXA651
Senior Master Sergeant
Posts: 2438
Joined: 15 Mar 2016, 08:23

Re: Manifold Pressure Selector Question

Post by alan CXA651 »

Hi Tom.
The main thing to remember when landing , is make sure you are not over weight on fuel , one hop i was on , not long after take off on max fuel load , i had a runaway turbo , and had to bring the throttle back to idle , but kept the engine running at idle , and continued on my journey , as i was carrying too much fuel to return to base , once i had burned off some fuel so a landing was possible , i diverted to the nearest airfield , on finals , i shut the bad engine down and feathered the prop.
On approach i normally reduce speed till gear and flaps can be deployed , once these are down and locked and established on finals , i reduce speed to 130mph as i get close to runway i reduce speed to 100mph , and as i cross the threashold i retard throttles slowly , at 90 mph the b17 should be close to runway surface and settle smoothely onto the runway.
the B17 can land without damage to gear on a light load of fuel , if you get proficiant with your landings , you might be able to land with light load plus 50 gal in each tokyo without braking the landing gear , word of warning , the landing gear links if damaged do not show up in the hangar , first you know about it is after take off when gear fails to retract , and cannot be hand cranked up , the only fix for broken link , is leaving the sim after landing and fixing any shown damage .
Once sim boots up again the undercarrage broken link is fixed.
regards alan. 8)
Image
Image
Image
Image

Tom347
Airman
Posts: 24
Joined: 19 Nov 2017, 06:20

Re: Manifold Pressure Selector Question

Post by Tom347 »

Alan,

I wasn't aware of the fuel load. How do I know what's the max? Is there a chart on landing weight in a manual someplace?

Thanks
Tom

new reply

Return to “B-17 Flying Fortress”

Who is online

Users browsing this forum: Amazon [Bot] and 10 guests