What is a Spitfire IX LF LR

[rossm]

The designation "Spitfire IX LF LR" appears a number of times in the 1 Squadron ORB for May 1944. Example aircraft are ML119, MK890, MJ796 and MK987.

 

Does anyone know what it means - I think the LF just refers to the supercharger? Is the LR a reference to a slipper belly tank being fitted and, if so, any particular size?

 

TIA,

Ross

[Graham Boak]

There was no specific designation given to Spitfires with the belly tank, but that wouldn't stop a squadron inventing its own.  Perhaps LF could be referring to the clipped wings, that being a more obvious feature, but  I suspect you are basically right that it meant those with the low-rated (not that low) Merlin 66-engined variant, strictly the LF Mk.IX but unofficially known as the Mk.IXB.   There were however other changes between the F Mk.IX and the LF Mk.IX, if not immediately obvious ones.

 

Do you have examples of the serials for aircraft that were not so described?  I don't suppose it'll help, but it might.  Given the right set of photos...

[brewerjerry]

Hi

   link to photo captioned as LF IX 

 

https://ingeniumcanada.org/aviation/collection-research/artifact-supermarine-spitfire-lf-mk-ix.php

 

  was the date for the LR spitfires to early for internal rear fuselage tanks ? 

 

   cheers

      jerry

Edited September 6, 2018 by brewerjerry

[rossm]

9 hours ago, Graham Boak said:

Do you have examples of the serials for aircraft that were not so described?  I don't suppose it'll help, but it might.  Given the right set of photos...

 

MK644 is described on one page as a IXb but I suspect the recording of variants is a bit random as it appears as a IX LF LR on another page!

 

I would like to model an a/c of 1 or 165 Squadrons based at Predannack and used on Roadstead 108 on 19th May 1944, the 1 Sqdn ORB is missing pages but here are the serials listed:

 

1 Sqdn: MK846, MK997, MK986 (maybe 966?), MK919 - the details column says 16 Spitfires LF LR IX of No.1 Squadron and 8 of 165 led by W/C Smallwood....... (I think there were only 16 in total from the 165 ORB).

 

165: MK751 T, MK564 Y, MK514 Z, MK854 H, MK749 L, MK855 E, MK638 B, MK426 D - The aircraft type column is headed "Spitfire IXb".

 

Given the code letters supplied in the 165 Squadron ORB thta's probably a better bet than a 1 Squdron a/c but, even so, trying to pin down exact details could be like grabbing a bar of wet soap.

 

I already have built a Spitfire VII of 131 Sqdn which flew top cover and, thanks to @Terry @ Aviaeology I can model one of the 404 Squadron Beaufighters that took part to make a 3 model "West Country" themed display based on a single operation.

 

 

[Graham Boak]

Yes, it's too early for aft tanks.

 

MK986 for sure, not MK966 which went to 313 Sq.  They all seem to be LF Mk.IXs, which is what you'd expect.    It looks like the LR does simply refer to the use of the belly tank - although I suppose it may mean the cylindrical one rather than the slipper?

[rossm]

Found a profile drawing of MK426 SK.D in Osprey Spitfire Aces of NW Europe 1944-5. That means there must be a photo somewhere? In any case it'll do for me although it would be nice to know if it should have a belly tank for Roadstead 108 and, if so, what type. The 165 ORB for 9th May refers to 90 gallon tanks being used for the first time and the sortie seems to have lasted 3hrs. Roadstead 108 only lasted 2hrs 25mins but I'm not sure how to translate that into a possible need for extra fuel.

[andyf117]

Content withdrawn - I will NOT be threatened by a moderator, simply because I queried the actions of another...

Edited June 27, 2020 by andyf117

[gingerbob]

2 hours ago, rossm said:

 

MK644 is described on one page as a IXb but I suspect the recording of variants is a bit random as it appears as a IX LF LR on another page!

 

"IXB" (or b) is a colloquial term for LF IX, which seemed to persist long after the officially blessed prefix was known.

 

I think the "LR" in this case is also just a local reference.  The Mk II with the silly tank bolted to one wing WAS known as an LR, so perhaps someone extrapolated.

 

Hopefully tomorrow I'll have time to look at the serials mentioned, but I don't expect that to reveal anything.

 

bob

[Graham Boak]

9 minutes ago, rossm said:

Found a profile drawing of MK426 SK.D in Osprey Spitfire Aces of NW Europe 1944-5. That means there must be a photo somewhere? In any case it'll do for me although it would be nice to know if it should have a belly tank for Roadstead 108 and, if so, what type. The 165 ORB for 9th May refers to 90 gallon tanks being used for the first time and the sortie seems to have lasted 3hrs. Roadstead 108 only lasted 2hrs 25mins but I'm not sure how to translate that into a possible need for extra fuel.

That's a long time for a Spitfire.  Did the 2hrs 25min include a combat?  If not, you'd have to add  perhaps 20 mins worth of fuel to the planned amount which will already include a diversion allowance.  The standard Spitfire had a 75 gall internal tank - endurance would vary with circumstance but as a crude guess I'd say an hour and a half, including any combat.  So we are talking about needing about double the amount of fuel,  It'll drink a lot more when heavy on the way out, but you have to allow much the same allowances for take-off, landing, diversion etc.  I can see why the planners thought that the 30 or 45 gallon tanks wouldn't be enough.  They of course had a much better idea of what was required, and if they thought that the 90 gallon tank was needed then we can be sure that it was!  Of course it may not have needed to be full - just more than the 45 galls otherwise available.

 

I think that with this rare use of the 90 gallon tank we have the answer to why the writer thought it worthwhile including the LR in the description.

 

The question arises about extra tankage for the 131 Sq Spitfire MK.VIIs on this mission.  The Mk.VII did have extra internal tankage anyway, adding up to 121 gallons.  So probably the 45 gallon slipper tanks would have done for them..

[rossm]

44 minutes ago, Graham Boak said:

That's a long time for a Spitfire.  Did the 2hrs 25min include a combat?  If not, you'd have to add  perhaps 20 mins worth of fuel to the planned amount which will already include a diversion allowance.  The standard Spitfire had a 75 gall internal tank - endurance would vary with circumstance but as a crude guess I'd say an hour and a half, including any combat.  So we are talking about needing about double the amount of fuel,  It'll drink a lot more when heavy on the way out, but you have to allow much the same allowances for take-off, landing, diversion etc.  I can see why the planners thought that the 30 or 45 gallon tanks wouldn't be enough.  They of course had a much better idea of what was required, and if they thought that the 90 gallon tank was needed then we can be sure that it was!  Of course it may not have needed to be full - just more than the 45 galls otherwise available.

 

I think that with this rare use of the 90 gallon tank we have the answer to why the writer thought it worthwhile including the LR in the description.

 

The question arises about extra tankage for the 131 Sq Spitfire MK.VIIs on this mission.  The Mk.VII did have extra internal tankage anyway, adding up to 121 gallons.  So probably the 45 gallon slipper tanks would have done for them.. 

That's a good point about the VIIs - they started from Harrowbeer and flew down to the rendezvous off The Lizard with no refuelling mentioned, 1 and 165 started from Predannack (on the Lizard) and the Beaus came from Davidstow. Checking the ORB the 131 Squadron sorties were 2hrs 35mins so I better put a slipper tank (45 gal) on my model! Now should that be in PRU blue to match the underside colour of ther High Altitude scheme or would it be in the more standard Medium Sea Grey? There were no other Spitfire squdrons at Harrowbeer at the time so I favour PRU Blue.

[brewerjerry]

Hi

    going from my memory of my harrowbeer research

   i think some of 131's spits were in standard day camo

  i.e.  

 

https://www.asisbiz.com/il2/Spitfire/RAF-131Sqn-NX/pages/Spitfire-MkVII-RAF-131Sqn-NXB-MD110-England-1944-02.html

 

https://www.deviantart.com/ws-clave/art/Spitfire-Mk-VII-GB-131-Sqn-84046952   

 

   so might not be pru blue, unless each tank was painted to match the individual aircraft colour ? 

   cheers

     jerry

Edited September 7, 2018 by brewerjerry

[gingerbob]

No.1 Squadron's LF IXs in May were almost all new aircraft- delivered to MUs during March, and to the squadron around 10-16 April, replacing the Typhoon.  165 Sqn had switched from F IXs to LFs at the end of March.

[rossm]

On 9/7/2018 at 12:43 PM, brewerjerry said:

Hi

    going from my memory of my harrowbeer research

   i think some of 131's spits were in standard day camo

  i.e.  

 

https://www.asisbiz.com/il2/Spitfire/RAF-131Sqn-NX/pages/Spitfire-MkVII-RAF-131Sqn-NXB-MD110-England-1944-02.html

 

https://www.deviantart.com/ws-clave/art/Spitfire-Mk-VII-GB-131-Sqn-84046952   

 

   so might not be pru blue, unless each tank was painted to match the individual aircraft colour ? 

   cheers

     jerry

 

On 9/8/2018 at 9:57 AM, gingerbob said:

No.1 Squadron's LF IXs in May were almost all new aircraft- delivered to MUs during March, and to the squadron around 10-16 April, replacing the Typhoon.  165 Sqn had switched from F IXs to LFs at the end of March.

Thanks both, so MSG tanks more likely I think for 131, and not much if any weathering for 1 sqdn and little more for 165 - 90 gallon tanks for either of these.. Now I only have to execute the plan!

Edited September 9, 2018 by rossm

[T-21]

L.F.     denotes  Low Altitude. These aircraft had a reduced diameter supercharger impeller. The Vb used the Merlin 45M . It had the option to have the clipped wing tips fitted but was not always fitted. Only the engine fitted is the only way to tell. in late 1943 the Mk.IXB  was re-designated the L.F.IXc  It used the Merlin 66 optimised for maximum power at 22,000 feet with six stack exhausts.

Edited September 11, 2018 by T-21

[Graham Boak]

The LF Mk.IX always was the LF Mk.IX.  The term LF Mk.IXB was unofficial front-line use for the aircraft with the lower-rated engine.  Be careful about the equation of LF with low altitudes.  The change in the full throttle height on the Merlin 66 was only a few thousand feet lower than that for the earlier 60-series engines but produced a superior performance over the majority of the operating range of the engine.

 

The LF Mk.V had an engine with a much lower rated full throttle height to around 5000ft.  Not just the 45M but also the 55M.  Some of these aircraft are also seen with six-a-side exhausts which may be linked to the use of the 55M, but I've not seen that proven.  For at least one example, it has been said that they were taken from a Mk.IX, but that may well simply be a bar story.

 

Clipped wings, indeed, were an option on any of the later Spitfires, and can be seen on Mk.Vs, VIIIs, IX, XIIs, XIVs , XVIs and even Seafires. I don't claim this as a complete list, but I'm not sure about Mk.XVIIIs.

•  

[rossm]

and here it is: https://www.britmodeller.com/forums/index.php?/topic/235045122-italeri-172-spitfire-ix-lf-lr/