2 planes that have wep and don't in AH

[colmbo]

FYI not all the information in the training book tells the whole story. 

For instance

The fuel in any tank is available to any engine supply tank in the airplane through a fuel transfer system consisting of 2 selector valves and an electrical transfer pump.

While it is true you can transfer fuel between tanks it isn't nearly as simple as they make it sound.  You can not transfer fuel directly from #1 to #2 or #3 to #4.  To transfer fuel to a tank on the same side (say 1 to 2) you first have to transfer that fuel to the opposite wing, either 3 or 4, then pump it back across the airplane.

Also in the fuel system they show for engines 2 and 3 the "fuel tank" and the "feeder tank".  While that is how the airplane is built, in use the tanks for #2 and #3 are thought of as a single tank.  They are plumbed together, it isn't possible to fill only one of the tanks or draw fuel from only one of them --- they work as a single tank.  Transferring fuel was a slow process, the transfer pump ran at a low volume, IIRC it was 12 gallons per minute.  Of course if you're coming back from Bremen on two engines and need that fuel moved....

Now one issue that can come up is since there is a fill port on top of the wing for each of the inboard tanks you have to ensure that you fill thru the forward tank otherwise you will think you are full, fuel spills out of fill port, but in fact you've only filled the aft 213 gallon tank.  Another issue that I've seen occur was the pilot sticking the tanks to check levels didn't pay attention and stuck both inboard tanks missing the outboard tank (#4 in this case).  #4 ran out of fuel before completion of the flying that day.

[Ciaphas]

That dial is an electronic turbocharger controller, not for setting WEP but for setting turbochargers to desired setting for the situation.  The B-17 I flew had the controller but the turbos had been disconnected.  We didn't fly high enough to need them and by disconnecting the ductwork we could get max allowable power without using the turbos.  The B-24 still used the turbos but had manual controls for setting boost...a separate lever for each engine.

Right, that was what controlled the WEP on the G model. It allowed you to over spin the turbos to gain the extra horsepower needed to supply required thrust at altitudes of 25k or more. Hence the reason it’s called WEP and the reason it’s listed in its specifications.

And that’s literally what WEP does


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[Krusty]

Ciaphas, an interesting read but not exactly what I'd call a prime resource/reference. It mentions some procedures to use but not exact RPM/manifold settings. While a few things on the Internet have mentioned the possibility of some kind of B-17G turbocharger "WEP" setting not one that I've read has any specifics, nothing indicates it was used, and our currently modeled speed curve closely matches Boeing's own maximum speed tests.

Let me ask you this: What manifold, RPM, and horsepower corresponds with this 2-minute WEP setting?

[Ciaphas]

There is the throttle quad with the manifold pressure selector.


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[bustr]

Along with your photo present Hitech with the pertinent documentation if it applies to the version of B17 in our game. Then wait a few years, or keep finding more documentation and presenting it. Have ever considered when he researches the aircraft he builds for his game the lengths he goes to, to be reasonably correct for that model? He won't change anything if that picture is your only evidence as I've seen over 15 years in these forums and playing the game.

Be careful this isn't an opportunity to hide venting at Hitech for not doing things in general you think he has failed at. I went through that with motor cannon not being able to elevate and finding an internal Rehinmetal document about the MK108 ballistics. Still, I went to the trouble over many years to find info to present which can be verified for the MK108 and how specifically motor cannon were mounted in many aircraft in WW2. None of them can be tilted up to change the default IP point from a bore sighting stand.

In short, you need to give him a compelling reason to use your data over his. 

[Ciaphas]

I really don’t see a use for it in the game on this particular aircraft. Was just stating that the misconception that the B-17 didn’t have WEP was not true.


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[colmbo]

Hmmm.  That placard certainly shows a WEP power setting.  I truly don't remember that in the -17 I have time in -- it had the placard, I just don't remember the WEP.  It has been 15 years since I've flown the airplane.  I'll have to dig thru some pics and see if I have one showing the throttles in Nine Oh Nine.

[Ciaphas]

You said the manifold pressure box was disabled, that could have been because the need for WEP isn’t needed anymore but more honestly in my opinion I think that it probably shelled more engines than it did good as running WEP on any engine for prolonged periods of time would end up requiring a full tear down and replacement of stressed components and on a four engine airframe it was probably not beneficial operationally and for maintenance crews as engine phase inspections are very tedious an often require major component replacement depending on the hours flown on each engine.




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[colmbo]

Okay, you need to realize that the turbo controller is there to adjust the turbo waste gates in order to obtain the desired manifold pressure during normal operation of the aircraft.....it is not there to enable WEP.

I didn't say the Controller was disabled, I said the turbo ducting had been disconnected which renders the turbos useless.  As for need, it would have been nice to have the turbos coming out of West Yellowstone with a density altitude around 7000'.

Speaking of turbos

[Ciaphas]

Right and opening the waste gate up or wide open is what allows the manifold pressure to climb to sufficient pressure to obtain the WEP hp that is listed


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[Ciaphas]

The manifold pressure selector dial regulates the amount of air flow to the manifold thus regulating the power output of the engines. Many of these manifold control boxes had a lockout feature that prevented it from being accidentally switched to full open.


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[colmbo]

Right and opening the waste gate up or wide open is what allows the manifold pressure to climb to sufficient pressure to obtain the WEP hp that is listed


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Wrong.  Opening the waste gate bypasses the turbo.  To increase manifold pressure you close the waste gate forcing exhaust gasses through the turbo spinning up the turbo which pumps more air into the engine.  More air means you can use more fuel.  More fuel means more power.

[Vraciu]

Hmmm.  That placard certainly shows a WEP power setting.  I truly don't remember that in the -17 I have time in -- it had the placard, I just don't remember the WEP.  It has been 15 years since I've flown the airplane.  I'll have to dig thru some pics and see if I have one showing the throttles in Nine Oh Nine.

This would be akin to augmented thrust.  Emergency use only for something like an engine failure on takeoff.   Is this a factory placard or a modern add-on?

[popeye]

Interesting that the B-17 could "HOVER".  I thought only the Tu-2s could do that. 

[DmdJJ]

Col, this is 909's throttle quadrant placard. You were correct that you never saw a WEP setting