Spitfire IXE - BOOST DIAL IN COCKPIT

[Ken5421]

Hi there,

 

Ok so the Spitfire IXE.

 

On the boost dial in the cockpit we have normal, then RED, then GREEN.

 

I'm assuming everything on the IXE for boost is automatic? Why is it that I'm never boosting beyond RED into the GREEN? Is it to do with altitude?

 

My concern is that I'm missing a setting to get extra boost

 

The older version of spitfire I like because you know when you hit boost it is done. But then easy to fry your engine if you go too long.

 

But the IXE. Am I missing anything???

 

Cheers

 

Ken 5421

 

 

[CountZero]

Trottle to 100% and rpm pitch to 100%, and thats it, no aditional boost key

its dependent on altitude what boost values you get and on what engine your using, but for low to mid alts it should be 18lbs boost, and only on weary high alts its below 10

[danielprates]

It IS odd that green follows red. Intuitively, green is "safe" operation and red is not. The instrument kinda leads you to error if you are not aware of the engine's operation parameters. I keep thinking of a german POW pilot spetacularly escaping, jumping into the cockpit of a stolen spit in order to escape, looking at the dials and saying "what the hell?!"

 

I wonder what was the reasoning behind that design choice for the instrument.

Edited June 1, 2019 by danielprates

[Mikoyan74]

What is the reading on the Instrument for Red/Green - there's a comment in the Flight Manual suggesting boost is not operated below 12 to prevent plug fouling so could be a lower limit?

 

[Ken5421]

Ok thanks guys. Interesting.

 

Just feels like the Spitfire is slow against the 109

 

Anyway I appreciate the feedback.

 

Cheers Ken 5421 

[ZachariasX]

30 minutes ago, Mikoyan74 said:

What is the reading on the Instrument for Red/Green - there's a comment in the Flight Manual suggesting boost is not operated below 12 to prevent plug fouling so could be a lower limit?

+12 lbs. boost is throttle lever at the gate, green values beyond that are boost values when pushing the throgh the through the gate.

 

Our Spit has a bit of a simplified throtte arrangement.

 

First, there should be a gate at which you will have to push the throttle to the side to allow it being pushed fully forward. On the Merlin 66/266 with 100 LL Avgas ("130 octane"),  this would be the range between +12 and +18 boost.

 

Then (on later models, as ours should be), there should be an interlink of throttle and propeller rpm lever, sort of turning the whole thing into a makeshift Kommandogerät.

 

See here, Paragraph 20, section (ii) from the plane manual:

 

(ii) On later aircraft the propeller speed control is interconnected with the throttle control. The interconnection is effected by a lever, similar to the normal speed control lever, which is known as the override lever. When this is pulled back to the stop in the quadrant (the AUTOMATIC position) the r.p.m, are controlled by the positioning of the throttle lever. When pushed fully forward to the MAX. R.P.M, position it overrides the interconnection device and r.p.m, are then governed at approximately 3,000. The override lever can be used in the same way as the conventional propeller speed control lever to enable the pilot to select higher r.p.m, than those given by the interconnection.
It must be remembered that the interconnection is effected only when the override lever is pulled back to the stop in the quadrant; indiscriminate use of the lever in any position forward of this stop will increase fuel consumption considerably.
At low altitudes (and at altitudes just above that at which high gear is automatically engaged) the corresponding r.p.m, for a given boost with the override lever set to AUTOMATIC are as
follows:

Boost (lb/.sq.in.) R.P.M.
Below +3 .. .. .. ..                         1,800-1,850
At +7..                                          2,270-2,370
At +12 (at the gate) .. ..             2,800-2,900
At +18 (throttle fully open) .. .. 3,000-3,050

 

 

Edited June 1, 2019 by ZachariasX

[CountZero]

25 minutes ago, Ken5421 said:

Ok thanks guys. Interesting.

 

Just feels like the Spitfire is slow against the 109

 

Anyway I appreciate the feedback.

 

Cheers Ken 5421 

Its not feeling, you are slower then 109s, even 109F4 is faster then M66 spit9 on all alts, if you wont to be faster then them fly m70 spit9 and abow 10km alt ?

[Ken5421]

On ‎6‎/‎1‎/‎2019 at 7:10 PM, 77.CountZero said:

Its not feeling, you are slower then 109s, even 109F4 is faster then M66 spit9 on all alts, if you wont to be faster then them fly m70 spit9 and abow 10km alt ?

 

good to know. thanks 

On ‎6‎/‎1‎/‎2019 at 7:04 PM, ZachariasX said:

+12 lbs. boost is throttle lever at the gate, green values beyond that are boost values when pushing the throgh the through the gate.

 

Our Spit has a bit of a simplified throtte arrangement.

 

First, there should be a gate at which you will have to push the throttle to the side to allow it being pushed fully forward. On the Merlin 66/266 with 100 LL Avgas ("130 octane"),  this would be the range between +12 and +18 boost.

 

Then (on later models, as ours should be), there should be an interlink of throttle and propeller rpm lever, sort of turning the whole thing into a makeshift Kommandogerät.

 

See here, Paragraph 20, section (ii) from the plane manual:

 

(ii) On later aircraft the propeller speed control is interconnected with the throttle control. The interconnection is effected by a lever, similar to the normal speed control lever, which is known as the override lever. When this is pulled back to the stop in the quadrant (the AUTOMATIC position) the r.p.m, are controlled by the positioning of the throttle lever. When pushed fully forward to the MAX. R.P.M, position it overrides the interconnection device and r.p.m, are then governed at approximately 3,000. The override lever can be used in the same way as the conventional propeller speed control lever to enable the pilot to select higher r.p.m, than those given by the interconnection.
It must be remembered that the interconnection is effected only when the override lever is pulled back to the stop in the quadrant; indiscriminate use of the lever in any position forward of this stop will increase fuel consumption considerably.
At low altitudes (and at altitudes just above that at which high gear is automatically engaged) the corresponding r.p.m, for a given boost with the override lever set to AUTOMATIC are as
follows:

Boost (lb/.sq.in.) R.P.M.
Below +3 .. .. .. ..                         1,800-1,850
At +7..                                          2,270-2,370
At +12 (at the gate) .. ..             2,800-2,900
At +18 (throttle fully open) .. .. 3,000-3,050

 

 

very interesting. thanks. Great information. Maybe current simplified throttle arrangement is to stop people easily frying their engines by pulling too many RPM for to long?

[ZachariasX]

1 hour ago, Ken5421 said:

very interesting. thanks. Great information. Maybe current simplified throttle arrangement is to stop people easily frying their engines by pulling too many RPM for to long?

Doubt that. We have a sim engine regimen that enforces her Majesty‘s playbook ratings, while in reality not just high (or: excessive) rpm represent a strain, but especially high torque configurations make your engine not last long. This means, the more power you want, the higher you have to rev the engine to actually have less strain on the engine. This is why manuals are adamant about using max. rpm should you intend moving the throttle lever through the gate. (How ironic, what is a good, helpful thing in teal life in game triggers „the timer“.) Also, with less rpm, the supercharger is less efficient. At intended low power settings, this is acceptable. Linkage just helps a very busy pilot maintaining meaningful configurations. Today, you don‘t use that linkage, as you use much less power than the linkage is set for anyway.

[Ken5421]

thanks