Tempest Mixture variable or restricted?

[56RAF_Roblex]

As far as I am aware the fuel mixture in the tempest should only have three positions i.e. it has three notches and in flight it sits in the 50% position and nowhere else (though I guess, as with other aircraft.  it could be set to 100% if the automation fails).   In the sim we can set the mix at intermediate positions and must sometimes fiddle to get it at 50%.  I know they can do such mechanics because they radiator shutter only does 0% & 100% and the Spitfires radiator flaps go in 20% increments so has 1C made a mistake or were the pilots actually allowed to set the mixture lever at intermediate positions?

The Tempest Pilots Notes do refer to a 'Weak' and 'Rich' continuous boost  in their performance tables but they also refer to what we call the 'mixture' lever as a 'three position cut-out lever' so maybe the table is just referring to the performance when the auto system itself chooses 'Weak' or 'Rich'?

Edited October 17, 2019 by 56RAF_Roblex

[DD_Arthur]

Eh?  I don't think I understand the question.  

 

Btw Spitfire flaps do not move in 20% increments.

[RavN_Sone]

He's asking if you can utilise the full range of mixture axis, or if u have to be very precise and only put it exactly on 50%.

In curious too actually. In many planes an automated position is specified as, for example, 70%. How precise does this has to be? Would +/- 5 work as auto as well? 

[R6ckStar]

4 hours ago, RavN_Sone said:

He's asking if you can utilise the full range of mixture axis, or if u have to be very precise and only put it exactly on 50%.

In curious too actually. In many planes an automated position is specified as, for example, 70%. How precise does this has to be? Would +/- 5 work as auto as well? 

Check the actual handle

 

For instance p47, to se the mixture to auto-lean set it foward of the line that says out lean and behind the line that says auto-rich.

 

I am not so sure about the other planes where 50% it is auto and the rest is a manual lean/rich setting. And if you have to set it exactly at 50% or there broad range

Edited October 17, 2019 by R6ckStar

[56RAF_Roblex]

5 hours ago, DD_Arthur said:

Eh?  I don't think I understand the question.  

 

Btw Spitfire flaps do not move in 20% increments.

 

Sorry. The 'Radiator' moves in 20% increments.

 

What I am saying is that we have this control on the panel that is marked as 'Start', 'Normal' and 'Cut Out'.  AT 'Normal' (middle) the mix is controlled automatically and at 'Cut Out' (bottom) the mix is weakened enough to stop the engine and at 'Start'  (top) the mix is 100%(?) and maybe some other things are done.  My question is about the fact that we are able to seamlessly set any % between the two extremes, eg 32% or 63%,  and I wondered if that is correct.  Should this control just have three possible positions in the same way that the  Spitfire Vs radiator flap can only be set to 0,20,40,60,80 & 100?   Looking at the lever there are no obvious notches but it does preclude the possibility that the pilot felt a definite notch at the 'Normal' position and knew that leaving the lever in any place other than top, bottom or middle would cause problems.   It might even have had to be pushed sideways slightly to move it.     The official pilots notes do not go into enough detail.

Edited October 17, 2019 by 56RAF_Roblex

[71st_AH_Rob_XR-R]

My understanding is the lever should have only three positions, start, Normal and cut-out.  This lever should not control mixture in between those three positions.  The mixture control is automatic and is engaged when that lever is in the "Normal" position.

 

The mixture changes between weak and rich at +4 lbs of boost. 

 

In short, we should not be able to alter the mixture in the Tempest manually.

[Lusekofte]

I found nothing in this site about mixture. But almost everything else. Maybe someone else can take a look. I am in a phone hard to read http://www.wwiiaircraftperformance.org/tempest/tempest-II-cfe.html

[Mauf]

I would assume the sim models it in 3 positions internally, mapped to the range of the assigned axis.  So just as a guess: 0-10% means cut-off, 11 to lets say 80 running normal and 81 to 100 emerg. rich. So while the lever moves smoothly, it's just these 3 states. IF that is the case, I would prefer the lever in cockpit to snap to these positions too just to reduce confusion.

[unlikely_spider]

11 minutes ago, Mauf said:

I would assume the sim models it in 3 positions internally, mapped to the range of the assigned axis.  So just as a guess: 0-10% means cut-off, 11 to lets say 80 running normal and 81 to 100 emerg. rich. So while the lever moves smoothly, it's just these 3 states. IF that is the case, I would prefer the lever in cockpit to snap to these positions too just to reduce confusion.

Me too - flaps work like that on specific planes that have hard stops on flap position, vs planes that can have flaps on any position between full and none.

[Quinte]

In game, the mixture lever is modelled correctly. I'm not home right now, but from memory it goes as follow:

- from 0% to 24%, mixture is in the cut out position

- between 24% and 73%, it's in the normal position

- from 74% up, it's in the start.

 

So you don't have to fiddle with it, set it roughly around 50% and you're good to go. The only thing missing afaik is that setting the mixture in the start position should induce a throttle stop at the start-up value.

Edited October 18, 2019 by Quinte

[Voyager]

Do we know what carburator the Napier Sabre used? 

 

The P-47 used a Stromburg carb, and while it did have three settings, it was possible to adjust it manually. 

 

Given the era, and the requirements of an altitude compensating carburator, I'd suspect you're adjusting a part of the control loop, rather than doing a hard setting, but that depends on the mechanism itself. 

[Quinte]

IIRC it used an SU carb. As far as I understand it you can only adjust it thorugh an adjustment screw on the carb itself. Might be wrong about that though.

 

Also note that currently in game, the start up procedure already includes setting the cut out lever back to "Normal" after the engine starts running. So it's basically already at 50%. If you have mixture mapped to an axis, you will need to move it to roughly the middle position, if you have it on buttons, you don't need to touch it ever.