Spitfire V, b vs c wing and UC details, and prop variants

[Troy Smith]

Hmm, a while back I started converting a Airfix 1/48th new tool Spitfire Vb wing to a c wing,  (and did the same in 1980 with the old tool kit.. )  

I did one wing, and never got around to doi the comparison photo,  which I'll do later as I'd like to restart this, as well as having got most of a DK decals RAAF Spitfire sheet cheap off ebay  

 

Now,  having been discussing this recently, and some questions or areas i'd like clarified

 

the C wing, apart from the new armament bays,  had the UC legs raked further forward 

the C wing introduced a 2 degree [iirc] forward rake to UC geometry.

VB

VC

Forward rake is obvious.

 

Now, IIRC part of this was accommodated by changing from a flat UC on the B to a curved down the centre door on the C ,  allowing the leg to come out of the wing slightly.

There are other minor differences, which is why the Eduard Merlin 60 kits have two sets of UC doors and gear legs? I'm not totally sure which set applies to what, or if this is any relevance to the Vc (though I'd like to scrounge the right type for a Vc conversion)

@gingerbob posted this is the thread I posted the above in

 

On 06/09/2014 at 15:59, gingerbob said:

For the record, the gear angle change was a feature developed with the Mk.III, which had a 2-speed Merlin XX. As Troy and other Hurricane fans will remember, that means the "core" engine moved 4" forward. It appears that there was already a tendency for the Mk.I to 'tip up', so this was a beneficial change even without the engine move. It was NOT on N3297, the first Mk.III prototype, despite frequent statements otherwise, but it was on W3237, which had the first 'Universal' wing. (The first prototype used a modified Mk.I wing, and this further complication was probably either not yet ready, or not considered worth delaying flight for.)

When it was decided to skip the Mk.III in favor of continuing the "temporary" Mk.V, the Air Min asked that the new armament arrangement be introduced as soon as possible, and inquired whether it could use the new wheel position. Joe Smith said that this would be no problem, but the Vc wing was a sort of hybrid, not the same structurally as the Mk.III's wing, which continued to evolve for the VII and soon VIII, while the Vc wing was further evolved for the IX. Since the 'Bowser wing' was an outgrowth of the a/b structure, the PR Spits didn't get the new gear angle until the PR.XI.

bob

 

There was also this thread on torque links,  now this is about VIII/IX UC oleos,  did the Vc leg change compared to the Vb? 

https://www.britmodeller.com/forums/index.php?/topic/234919094-spitfire-landing-gear-oleos/

 

A point that I was asked was did the UC well change on the B vs C wing,   now AFAIK, no, the change is in the leg angle, and this was allowed for by the curved door.

 

Props, 

3 types? 

The long Rotol type, 

as seen on this

 

Short De Havilland type

Short Hamilton hydromatic

as seen on the RAAF Vc, as IIRC  they had problems with them freezing at altitude

 

I maybe wrong about the last two,  (and they are the same type?) so clarifications appreciated, on this, and any other aspects.

A did through Spitfire the History didn't turn up much of this detail, (forgot to check the props section) 

 

Not the best worded questions I'm afraid,  but I don't recall seeing a thread on all this, and it's been a while since we had a good Spitfire detail thread  

 

look forward to what this turns up.

 

 

 

 

[gingerbob]

1 hour ago, Troy Smith said:

There are other minor differences, which is why the Eduard Merlin 60 kits have two sets of UC doors and gear legs?

 

Three, actually, at least for the Mk.VIII.  These provide for splined (that'll probably cover most Mk.Vc), aft-link (some Vc, at least retrofit), and front-link.  But all are for 'c' wings- though I'm not sure the plastic would know the difference!  I'm not sure that the aft-link type is in any other boxing (it is in the "HF.VIII" boxing, which is, in fact, F.VIIIs).

 

Some have said that the later Hydromatic spinner is different, but I have a hard time seeing it, and I don't have any documentation concerning it.

Edited March 23, 2019 by gingerbob

[Dave Swindell]

As far as I'm aware there was no change to the wing structure due to the change in rake of the undercarriage legs.

The rake angle was changed by inserting a wedge shaped spacer in the leg mounting position between the spar and the leg hinge trunion. The mounting bolts passed through the wedge spacer, which set the new rake angle when all was tightened up.

As the hinge geometry didn't change, the leg still retracted into the same well space, but the wheel now sat in the well slightly more nose high than before. The gear doors still fitted, they just needed rotating on the leg slightly so they were flush with the wing.

Additions of torque links to the oleos required adjustments to the shape of the well and door where the wheel cover met the leg cover to allow for retraction due to the projection of the links outside the old well/door outline.

[Graham Boak]

I'm not sure how you can change the rake angle without changing the hinge geometry.  However what is missing from this account is the replacement of the bulge in the upper wing by a thicker hence stronger smooth surface.  This means that the wheel had to sit slightly lower, so that the leg no longer fits so well into the well.  Hence the raised curve on the wheel door.

[Admiral Puff]

As a sideline: the RAAF had all sorts of problems with their Vcs, due in no small measure to the fact that they operated them at much higher altitudes (typically 25-30,000 ft) than the RAF normally did in either Europe or the Middle East. Guns froze and prop CSUs misbehaved. To get a much more detailed insight, see Anthony Cooper's Darwin Spitfires (New South Publishing, 2011, ISBN 978 174223 227 0, Dewey 940.54269414). No connection, other than my interest in Australian aviation history.

[Graham Boak]

A superb book, if a little uncritical of the RAAF in places.  He didn't seem to be aware of the earlier decision in the UK to recommend Rotol propellers for high altitude operation because of these very failures of the DH propellers at high altitudes and constant rpm - hence the recommendation (which he did notice) to vary the power settings regularly to ensure free movement of the pitch control.  He notes that this would have created problems in the formation interceptions, but not doing so was quite clearly worse!  It is difficult to find other operations of the Mk.V at these altitudes, but examples can be found from Malta and North Africa of aircraft returning early because of propeller problems or cannon jamming.  These appear much rarer at these lower operating altitudes than in PR or Darwin operations, but this could be an artefact of the historian not being primed to highlight them - or of course my eye primed to be picking them out when they really were uncommon.  Perhaps we have here a failure of Allied Intelligence sources to notice and report on the high altitudes of Japanese bomber operations, though in fairness there had probably been few cases outside China where these medium bombers had been seen operating at such altitudes and ranges.  The still-prevalent discounting of Japanese technologies (not entirely unjustifed), the Zero aside, possibly helped here.  Who'd have thought, in the UK at that time, that the Japanese bomber force would present problems so much more difficult than the Luftwaffe did?

[Dave Swindell]

22 hours ago, Graham Boak said:

I'm not sure how you can change the rake angle without changing the hinge geometry.

Sorry Graham, my poor description, was in a rush.

Hopefully below with pictures will help.

Here's a photo of the spitfire undercarriage test rig at East Fortune

The wedge insert is highlighted with the red arrow, and again here in close-up, where the top of the wedge insert is highlighted

To the left of the insert is the rear of the main spar

To the right of the insert is is the undercarriage leg hinge pintle and gudgeon

It was this assembly that I was referring to with the unchanged geometry, this assembly was previously bolted directly to the rear of the main spar.

Introducing the wedge has moved the top of the leg aft, which with the leg extended has the effect of moving the wheel forward  relative to it's original position.

With the leg in the retracted position, the main effect is to rotate the leg so that the front of the wheel is higher.

It also moved the leg (in the retracted position) slightly aft, and slightly down relative to it's original position

My understanding is this aft and down position change, and the rotation didn't affect the stowage of the leg in the original well (ie there was sufficient clearance to accommodate it) and there was sufficient adjustment in the door mountings on the leg to correctly re-position the leg - if I'm wrong on this it could also be reason for the introduction of dished (convex) doors.

There's a good picture of the pintle mounted directly to the spar on the BoB's Vb AB910 on p67 of the Haynes Spitfire manual.

 

[72modeler]

Incredible photos and explanation, Dave! Thanks for sharing with us. Is that the top of the aft-facing oleo scissor visible just above the wheel in the top photo?

Mike

[Dave Swindell]

18 minutes ago, 72modeler said:

Incredible photos and explanation, Dave! Thanks for sharing with us. Is that the top of the aft-facing oleo scissor visible just above the wheel in the top photo?

Mike

Yes Mike, that's a scissor link. The exhibit in the photo is I suspect an educational demo rig from a technical school, and it's brilliant for getting an all round look at how the u/C works on a Spitfire. I've been racking my brain to try and remember where the orignal info about the wedge came from. I seem to remember Supermarine designers thinking they would have to re-engineer the whole leg and hinge joint to move the wheel forward until some bright spark said why not just stick a wedge in?

[NPL]

turning to the modeller's point of view: Tamiya's way of handling the undercarriage at their new Mk.I will make it a piece of cake to adjust the angle of the legs if they choose to do the Mk.Vc. It is only to change one piece (and then of course the other changes). 

[Admiral Puff]

Many, many moons ago there was a long and detailed series of letters in Scale Models about torque links (or the lack thereof) on Spitfire undercarriages. I can't lay my hands on it at present, but IIRC it was back pre-SAM.  If I find it I'll update this post.

[pacificmustang]

I vaguely remember those Admiral Puff.  They appeared in issues following their review of the Frog MKVIII if that helps in your search

 

Bruce

[NPL]

Could it be this?

 

Scale Models Jan 1975

 

My notes say an extended review of 1/72 VIII/IX. I have it upstairs somewhere, so if somebody else has an easier access...

[Tomas Enerdal]

Dear All,

Way back, Vasco Barbic presented a study of Spitfire wings in an issue of Scale Aviation Modeller. He described the differences in armament as well as the redesign of the wing/landing gear in the Universal wing. I have it at home  somwhere, will dig it out tonight. (He did a corresponding study in the various Spitfire nose configurations as well)

Regards,

Tomas Enerdal

[NPL]

5 hours ago, Tomas Enerdal said:

Dear All,

Way back, Vasco Barbic presented a study of Spitfire wings in an issue of Scale Aviation Modeller. He described the differences in armament as well as the redesign of the wing/landing gear in the Universal wing. I have it at home  somwhere, will dig it out tonight. (He did a corresponding study in the various Spitfire nose configurations as well)

Regards,

Tomas Enerdal

Do you know the time frame? I have the complete series of SAM and easy to find, if I know where to look for it.

[Tomas Enerdal]

Yes,

It is Scale Aviation Modeller Vol 2 Iss 3 March 1996. Covering wings fitted to fighter a/c, not the XIX, nor the Mk21-, however.

In short; There is the earler wing with "A" or "B" armament.

Then came the "Universal wing". Quote:

"It is at this stage that the wing underwent a major change. ...reduce labour and manufacturing time... make the wing suitable for various gun combinations without any further alterations. This was successfully achieved by modifying the main under carriage and its locking device (as a consequence the struts retracted slightly proud of the undersuface) and by eliminating some surface details, such as the blisters ower the whell wells. ...results was the "Universal wing", sometimes called the "C" wing.   ...larger radiator... Hispanio guns adapted for the new Chatellerault ammuniton belt fed unit.... as a consequence of the under carriage being modified, the door was no longer flat but convex."

Then came the "E" wing ...basically the Universal wing without leading edge machine gun ports... Specifically produced to carry the "E" armament which consisted of only one Hispanio MkII 20 mm cannon and a .50 heavy mashine gun in the inboard cannon bay. ...and with strengteningof the main spar and structure to the Mk XVIII,... "(with other differences as well, but thats another story)

 

In Scale Aircraft Modelling Vol 20 no 7 September 1998 mr Barbic discusses various noses, engines, spinners, propellers, exhausts, intakes, humps and details of all fighter Spit noses from MkI to Mk24.

 

IMHO, these two short articles (even if they are now 20+ years old) are the best possible summaries available, I tend to get back to them every time I think about, or build Spits.

 

Tomas Enerdal

 

Edited March 27, 2019 by Tomas Enerdal

[greatgonzo]

Awhile ago Edgar told me, it was not possible to him to find out if the wedge remained as a part of C-wing undercarriage construction till the end, or was it replaced by redesigned oleo leg. Any news here maybe?

He also added, the instructions were issued to tighten the bolts with special care, when fixing the legs with the wedge added.

[Troy Smith]

Regarding  the props fitted

 

Spitfire the History has this

 

De Havilland  type 5/29A hydromatic

De Havilland  type 5/39A hydromatic

De Havilland  type 45/1 hydromatic

De Havilland  type 45/4 hydromatic

all 10 ft 9in  diameter

or

Rotol RX5/10  - 10ft 3 in diameter

Rotol RX5/14 

Rotol RS5/24 both 10ft 9 in diameter 

 

I'm wondering if @Mark12  or anyone else maybe able shed any light on how the maybe appear different to the eye of the modeller?    

Are these the two unit supplied in the Airfix new tool 1/48th  Mk.Vb kit?

 

thanks

T

 

 

 

 

[Kallisti]

Interesting stuff, have always been toying with the idea of converting the Hobbyboss 1:32 Vb to a Vc at some point...

[Peter Roberts]

There was a very detailed discussion on Spitfire U/C legs here some time back, discussing splined and linked legs and where they were fitted. I am not that organised to have details to hand and the search facility doesn't help. Maybe others recall and have it noted?

 

PR

 

PS Here 

 

Edited April 2, 2019 by Peter Roberts

[Pete M.]

Unfortunately, all the photos are gone from that linked thread! 😢

 

Cheers,

Pete M.

[Troy Smith]

On 02/04/2019 at 13:47, Troy Smith said:

Regarding  the props fitted

 

Spitfire the History has this

 

De Havilland  type 5/29A hydromatic

De Havilland  type 5/39A hydromatic

De Havilland  type 45/1 hydromatic

De Havilland  type 45/4 hydromatic

all 10 ft 9in  diameter

or

Rotol RX5/10  - 10ft 3 in diameter

Rotol RX5/14 

Rotol RS5/24 both 10ft 9 in diameter 

 

I'm wondering if @Mark12  or anyone else maybe able shed any light on how the maybe appear different to the eye of the modeller?    

 

Are these the two unit supplied in the Airfix new tool 1/48th  Mk.Vb kit?

 

Giving this a bump as no response on this, perhaps @Junchan  may know if there are visual differences between these props types? 

thanks

T