Typically / historical flight profiles crossing the channel?

[Emacs]

Hi there,

 

I‘m new to the Spit and enjoying this module very much.

 

Mostly I‘m flying on the Normandy map out of Tagmere.

I have built a mission which allows me to train a lot of mission types near that airfield.

 

Lately I flew my first missions over the channel over to Caen and Le Havre.

 

I must have done something stupid (more than usual) because my fuel wasn‘t enough to get me home again.

 

Was it my flight profile? I climb out of Tangmere up to 30000ft and reach that hight about halfway over the channel: Admittedly a quite aggressive climb, I guess. +3000 ft/min at 160Kts most of the time. 2650rpm and boost depending on hight.

Shortly after top of climb I decent again to about 10000ft over the coast of France.

 

By this time my upper fuel tank is empty and about half of the content of the lower one is gone too.

Three quarter of my total fuel consumed during ingress is not a promising perspective for an avid student pilot…

 

How where pilots flying the Spit back then?

Not so high?

Slower?

With external fuel tanks?

 

Cheers,

 

Emacs

[Terry Dactil]

Have a look at this thread ...

The Spitfire was designed as a short range interceptor with only about 200 miles range. (that is out and back, not a radius.)

It is a bit over 100 miles from Tangmere to Le Havre.

You can see why drop tanks were invented. 

[Emacs]

Thanks a lot !

Then I wasn't actually too far off.

I haven't expected that the Spit would have so much less range then the other warbirds.

 

Better get those external tanks added !

 

Cheers,

 

Emacs

[grafspee]

For more economy flight you can force supercharger to stay in first gear, there is a switch for that next to supercharger second gear light.

Climb to 18k-20k ft then move switch to M.S position, you can save a lot of fuel by doing so.

For flight across the channel you don't need 30k ft, 20k is very ok. It is just wasted fuel for extra 10k if you need to descent just right after you hit 30k

Edited May 10, 2021 by grafspee

[DD_Fenrir]

Prototypically, it depended on the mission as to what profile you would fly.

 

1. RAMROD

a. Escort to US Mediums - RV usually Beachy Head, Rye or mid-Channel, Angels 10-12.

Climb from base at 2650 +7lb @180mph IAS (hint: keep the Boost at 7lb or below to use a leaner fuel mixture setting) to RV. Once established at height reduce to 1800-2200 RPM and -2 to +4lb Boost whilst out over the sea. As enemy territory approaches, increase to max continuous and hold this over enemy territory. Reduce to the more economical settings when chance of engagement by enemy is negligible.

 

b. Escort to RAF light bombers - RV usually Beachy Head, Angels 0.

After takeoff, once established at treetop height reduce to 1800-2200 RPM and -2 to +4lb Boost. Hold these settings for RV when joined and proceed to pre-arranged mid-Channel point at wave-top height. There, all aircraft climb to medium altitude (Angels 10-16) - use 2650 +7lb @180mph IAS, aiming to cross the enemy coast >Angels 10. Hold this setting over enemy territory. Reduce to the more economical settings when chance of engagement by enemy is negligible.

 

2. RODEO

Fighter Sweep

Climb from base at 2650 +7lb @180mph IAS. Once established at mission height reduce to 1800-2200 RPM and -2 to +4lb Boost whilst out over the sea. As enemy territory approaches, increase to max continuous and hold this over enemy territory. Reduce to the more economical settings when chance of engagement by enemy is negligible.

 

As grafspee indicates, if you're above ~Angels 15/16 and the Supercharger has engaged, as long as you're not expecting to run into trouble, manually switching out the second stage of the supercharger is a good way to save some juice.

 

From 1942 nearly all Spitfire missions cross-Channel would have used jett-tanks.

[grafspee]

Spitfire with Merlin 66 has 2 stage 2 speed supercharger, 1st and 2nd stage are working all the time, only speed can be changed.

[Mr_sukebe]

4 hours ago, grafspee said:

For more economy flight you can force supercharger to stay in first gear, there is a switch for that next to supercharger second gear light.

Climb to 18k-20k ft then move switch to M.S position, you can save a lot of fuel by doing so.

For flight across the channel you don't need 30k ft, 20k is very ok. It is just wasted fuel for extra 10k if you need to descent just right after you hit 30k

 

 

Quick question on that.

Within Chuck's guide, the "max range" is listed as when you're running at 1000m (just over 3k feet).

Whilst it might not be very sensible to run at that altitude from a combat perspective, does that mean that it's also the most fuel efficient?

[grafspee]

I doubt that this is correct, i don't have charts for spitfire but i have charts for P-51

chart for 10600 to 10000 pounds with 2 500lbs bombs.

5k ft 2600rpm 44" 84GPH 300 MPH TAS

15k ft 2150rpm F.T. 66GPH 300MPH TAS

Looks like it burn less at the same speed at higher alt.

9600 to 8000 with wing racks only.

5k 2700rpm 46" 92GPH 340MPH TAS

25k 2050rpm F.T 60GPH 335MPH TAS

Probably same case with spitfire.

Edited May 10, 2021 by grafspee

[Emacs]

16 hours ago, DD_Fenrir said:

Prototypically, it depended on the mission as to what profile you would fly.

 

1. RAMROD

a. Escort to US Mediums - RV usually Beachy Head, Rye or mid-Channel, Angels 10-12.

Climb from base at 2650 +7lb @180mph IAS (hint: keep the Boost at 7lb or below to use a leaner fuel mixture setting) to RV. Once established at height reduce to 1800-2200 RPM and -2 to +4lb Boost whilst out over the sea. As enemy territory approaches, increase to max continuous and hold this over enemy territory. Reduce to the more economical settings when chance of engagement by enemy is negligible.

 

b. Escort to RAF light bombers - RV usually Beachy Head, Angels 0.

After takeoff, once established at treetop height reduce to 1800-2200 RPM and -2 to +4lb Boost. Hold these settings for RV when joined and proceed to pre-arranged mid-Channel point at wave-top height. There, all aircraft climb to medium altitude (Angels 10-16) - use 2650 +7lb @180mph IAS, aiming to cross the enemy coast >Angels 10. Hold this setting over enemy territory. Reduce to the more economical settings when chance of engagement by enemy is negligible.

 

2. RODEO

Fighter Sweep

Climb from base at 2650 +7lb @180mph IAS. Once established at mission height reduce to 1800-2200 RPM and -2 to +4lb Boost whilst out over the sea. As enemy territory approaches, increase to max continuous and hold this over enemy territory. Reduce to the more economical settings when chance of engagement by enemy is negligible.

 

As grafspee indicates, if you're above ~Angels 15/16 and the Supercharger has engaged, as long as you're not expecting to run into trouble, manually switching out the second stage of the supercharger is a good way to save some juice.

 

From 1942 nearly all Spitfire missions cross-Channel would have used jett-tanks.

Great post!!

Thank you

[KitKatCarson]

21 hours ago, grafspee said:

I doubt that this is correct, i don't have charts for spitfire but i have charts for P-51

chart for 10600 to 10000 pounds with 2 500lbs bombs.

5k ft 2600rpm 44" 84GPH 300 MPH TAS

15k ft 2150rpm F.T. 66GPH 300MPH TAS

Looks like it burn less at the same speed at higher alt.

9600 to 8000 with wing racks only.

5k 2700rpm 46" 92GPH 340MPH TAS

25k 2050rpm F.T 60GPH 335MPH TAS

Probably same case with spitfire.

 

 

Range for piston engine airplanes remains almost constant across all altitudes (see page 160 of aerodynamics for naval aviators)

 

Higher altitudes will result in a higher TAS allowing you to use the same available range more quickly, but you wont get further.

 

The only thing to consider is gliding range if you're expecting to run out of fuel before reaching wherever you're going.

[grafspee]

True, but i had something different in mind. TAS will increase at high alt so you can drop off the power, be on spot about same time with less fuel burned.

Simple trade TAS for fuel.

Edited May 11, 2021 by grafspee