Vol 2 All the Spitfire questions here

[gingerbob]

No, that's the port side, and the generator cooling air intake/exhaust.

[Ray_W]

Apologies. Yes. Should be ...

 

 

 

[Max Headroom]

1 hour ago, Ray_W said:

Thanks Graham for the quick response. Intended aircraft is A58-303; an Aussie LF. It looks like narrow canon bulges and no wing tip extension.

 

Ray

 

Interesting in that it has the retractable tail wheel in the locked-down position.

 

Trevor

[Ray_W]

9 minutes ago, Max Headroom said:

Interesting in that it has the retractable tail wheel in the locked-down position.

It may have nothing to do with it but also interesting to note that this particular aircraft was used for high G manoeuvres testing the later developments of the Cotton Anti-G suit.  

[72modeler]

3 hours ago, Ray_W said:

The position of the crankcase breather vent shifted from Merlin 61 to 66

Wow! I never noticed that before! Looks like the same as the ones you see on Mustangs. Was this vent only on Spitfires that had the Merlin 66 or 70, as I don't recall seeing one  on the Spitfires with earlier versions of the Merlin...or was it just in a different location? Damn- now I have to go back and re-examine all my Spitfire photos!

Mike

 

 

 

 

 

[gingerbob]

Thanks to Wojtek Matusiak for bringing it to my attention.  I think the earlier position was (maybe) a bit higher and further back?  I'd have to go looking to find where he points it out.  I think it's on all 60-series, and I imagine earlier ones too, though that's just an assumption.

[Spitfire madman]

Hi all 

im a little confused with the types of propeller blades fitted to mkix spits I always thought they were made of wood but while I was on the internet I came across these pictures and noticed the blades were bent rather than shattered which I would of expected 

 could anyone enlighten me 

many thanks

pictures from the the Free Czech Air Force website 

https://fcafa.com/2012/09/19/spitfire-aircraft-of-310-sqn-312-sqn-and-313-sqn/

 

 

[72modeler]

11 hours ago, Ray_W said:

The position of the crankcase breather vent shifted from Merlin 61 to 66

Wow! I never noticed that before! Looks like the same as the ones you see on Mustangs. Was this vent only on Spitfires that had the Merlin 66 or 70, as I don't recall seeing one  on the Spitfires with earlier versions of the Merlin...or was it just in a different location? Damn- now I have to go back and re-examine all my Spitfire photos!

Mike

 

 

 

 

 

[72modeler]

@Spitfire madman,

 

See section 2.4 in the linked article below. I had forgotten there were two different types of Rotol propellers installed on Mk IX's- does this answer your question? (Can't believe I beat @Troy Smith off the starting block on this one!)

Mike

 

http://www.spitfireperformance.com/en524.html

[Dave Swindell]

8 hours ago, 72modeler said:

does this answer your question?

Not really, Hydulignum and Jablo were both types of wooden blade

[72modeler]

21 minutes ago, Dave Swindell said:

Not really, Hydulignum and Jablo were both types of wooden blade

OK- I was able to find a source that stated that Mk IX's fitted with Merlin 61's were fitted with Jablo R3/4F5/3 four blade props with dural blades, which if I remember correctly, would be metal? There was evidently a forum discussion on these propellers a while back on Britmodeller, but I don't know the date- you could do a forum/topic search, I guess, or an internet search for that Jablo prop type. Best I can do- I'm certainly no Edgar Brooks! Maybe @Graham Boak could help you.

Mike

 

I also just found this list that might be helpful- I can't vouch for how accurate it is, however.

http://www.aeroscale.co.uk/modules.php?op=modload&name=SquawkBox&file=index&req=viewtopic&topic_id=88691&page=1

Edited April 9, 2020 by 72modeler
added link

[Work In Progress]

20 hours ago, Max Headroom said:

Interesting in that it has the retractable tail wheel in the locked-down position.

 

Trevor

Not entirely unusual, the mechanism is not the most reliable part of the aeroplane, the performance reduction is small (about 3-4 knots) and under many circs it's better than taking an airframe out of service for a retraction mechanism repair, or risking losing it to a substantial tail repair if it jams in the up position.  If I had a retractable-tailwheel Spitfire today - fat chance, but I still speculate idly - I would be likely to lock the tailwheel down permanently, and make up a removable panel closing off the bay.

Edited April 9, 2020 by Work In Progress

[Work In Progress]

1 hour ago, 72modeler said:

OK- I was able to find a source that stated that Mk IX's fitted with Merlin 61's were fitted with Jablo R3/4F5/3 four blade props with dural blades, which if I remember correctly, would be metal?

Jablo as a company only made wooden blades: it was what they did. They did not make complete constant-speed props. They supplied the blades to Rotol (the Rolls / Bristol joint venture) in just the same way as did Hordern Richmond, another blade manufacturer.

Edited April 9, 2020 by Work In Progress

[Ray_W]

1 hour ago, 72modeler said:

Mk IX's fitted with Merlin 61's were fitted with Jablo R3/4F5/3 four blade props with dural blades

Hi Mike, If you said Rotol instead of Jablo (a blade manufacturer) you would of got it right. It's the Rotol R3/4F5/3. Dural is a metal alloy, that is duraluminium or, if you like, duralumin, of aluminium with copper, mangnesium and manganese. I suppose different suppliers used different alloy mixes dependent on requirements. Ray

[Dave Swindell]

1 hour ago, 72modeler said:

OK- I was able to find a source that stated that Mk IX's fitted with Merlin 61's were fitted with Jablo R3/4F5/3 four blade props with dural blades, which if I remember correctly, would be metal? There was evidently a forum discussion on these propellers a while back on Britmodeller, but I don't know the date- you could do a forum/topic search, I guess, or an internet search for that Jablo prop type. Best I can do- I'm certainly no Edgar Brooks! Maybe @Graham Boak could help you.

Mike

Hi again Mike, that type number looks more like a Rotol number for a complete propeller than a Jablo number for prop blades. Jablo had a patent on making compressed wooden propeller blades, and as far a I'm aware that's all they did. Rotol bought in either finished blades or blanks for final machining and fitted them to their hubs. Rotol also made their own blades, including dural ones, and I suspect that this is what we're seeing on the photo above.

There's some useful diagrams of Rotol propellers and 3 types of wooden blades fitted to them here http://www.enginehistory.org/Propellers/Rotol/rotol.shtml

Other discussions on Spitfire/Rotol/Jablo propellers are here:

https://www.key.aero/forum/historic-aviation/79363-questions-on-spitfire-propellers-merged?page=0

 

[303sqn]

THE USE Of WOOD FOR AIRCRAFT IN THE UNITED KINGDOM

Report of the forest Products Mission June 1944

 

Three types of propellers made from compressed wood are now in production in the United Kingdom and several other types are in various stages of development. Fixed-pitch, wood propellers of conventional type are in extensive use on various training airplanes.

 

Weybridge Blade

 

This blade, which is made by the Airscrew Company, Ltd., is carved from a blank glued from boards of Douglas-fir scarf joined, at the root end, to "Jicwood” or to similar “compreg" supplied by firms in the United States. Jicwood, supplied by the firm, Jicwood, Ltd., associated with the Airscrew Company is prepared by coating Canadian birch veneers with about 4 percent by weight of a spirit-soluble phenolic resin, drying, and then consolidating the pack under heat and pressure. The resin content and the conditions of pressing are such that Jicwood is not stabilized appreciably either by the resin or by the action of heat and moisture. The blank is rough-carved by machine, and then finish-carved and balanced by hand. Due principally to the time required for conditioning at various stages of manufacture, the elapsed time for a blade in production is from 7 to 12 weeks.

 

In one type of finishing, the blade is covered with hessian cloth cemented in place. A brass leading-edge strip is sweated to brass gauze and hammered, screwed, and riveted in place. A thick sheet of either cellulose nitrate or cellulose acetate is cemented on and the whole blade is placed in a rubber bag and put in an autoclave. In the autoclave treatment the coating is said to penetrate the Douglas-fir blade to a depth of about 1/8 inch. In the second type of finishing the blade is liberally spread with a thick lacquer and a sheet of cellulose ester is rolled into place on each face, forming laps at the leading and trailing edges. After the coating has shrunk, the laps are carefully sanded. Final balancing is done,by local scraping, and, if necessary, balancing paint is used locally.

 

These blades are repaired by splicing a new piece to the undamaged portion. Although repair of a damaged root is never attempted, the entire Douglas-fir portion of the blade may be replaced, the new scarfs nearly coinciding with the old. If the coating is not too badly injured, it is repaired locally.

 

Hydulignum Blade

 

The Hydulignum blade is manufactured by Hordern Richmond Aircraft, Ltd. One thirty-sixth-inch birch veneer is coated with approximately 20 percent of Formvar (polyvinyl formal) by weight. After the solvent (trichlorethylene and alcohol) has been driven off, the veneer is pressed into panels of specific gravity 0.95 at an elevated temperature and then cooled in the press. Two corners of the board are trimmed off and that end is then further compressed sidewise to a specific gravity of 1.3. The final board thus has a high-density double-compressed root, a transition zone, and a medium-density blade and tip. After rough patterning, several boards are assembled into a blank with a cold-setting urea-formaldehyde glue and the blank is carved in the same way as the Weybridge blade.

 

After several coats of primer containing chlorinated rubber, and of Formvar varnish have been applied, a brass leading-edge strip is riveted and screwed in place. About 14 additional coats of Formvar complete the blade.

 

A particular advantage claimed for the Hydulignum propeller is that the equalized shear strength in the root, in the two planes parallel and perpendicular to the glue surfaces, permits the use of smaller diameter hub fittings. Practical considerations requiring the use of a standard hub for all-wood blades, however, has precluded the use of a smaller hub for the Hydulignum blade.

 

Jablo Blade

 

This type of blade is manufactured by F. Hills and Sons, Ltd., and Jablo Propellers, Ltd. Veneers 0.6 mm. (1/42 inch) thick and of varying length are interleaved with phenolic-resin film glue and assembled in such a way as to give boards of 69 plies at the root and 48 at the tip. The assembly is pressed to a uniform thickness at a gradually increasing temperature reaching a maximum of about 280° F. The boards are roughly profiled, then assembled with casein glue. Carving is done by machine, followed by manual final carving. A stocking of phosphor-bronze gauze is stretched over the blade and soldered along the trailing edge. After application of a brass or steel

leading-edge strip, many coats of phenol-formaldehyde enamel are brushed on and baked so as to build up the surface flush with the metallic sheathing. After a final balancing, the blade is given a coat of grey primer and one of cellulose-acetate lacquer. (Since the return of the Mission, it has been learned that the type of finish described for the Jablo blade is no longer employed and has been replaced by a finish similar to that of the Hydulignum blade. This leaves two types of propeller finishes in use; namely, (1) cellulose acetate or cellulose nitrate (cellulose esters), and (2) "Cristofin," as developed by Hydulignum.)

 

Experimental Blades

 

F. Hills and Sons, Ltd., have three new types of propeller blades in development: the Norton, the Trafford, and the King. The Norton blade is made from boards each of which has approximately the same density throughout its length. The blank is glued up with four outer boards of specific gravity 1.3, and three inner boards of specific gravity 1.1.

 

The Trafford blade has a root consisting of alternate boards of specific gravity 1.3 and 0.9 scarfed to a blade of natural spruce to which are also glued densified birch leading and trailing edges of specific gravity 0.9. Both these types were designed to minimize the strain on the press Caused by eccentric loading. In addition, the Trafford is expected to be lighter and stiffer than the Jablo.

 

The King blade is a molded, uniform-density, hollow blade. Birch veneers mm. (1/8.5 inch) are tailored to a calculated shape, rolled into long tubes, impregnated with a phenol-formaldehyde resin, and dried. A large number of these tubes are loaded side by side into a steel die having a solid steel core. Heat and pressure flatten the tubes and consolidate the into a blade Of specific gravity 1.3 with a maximum wall thickness of about 3/4 to 1 inch. The core is removed after the pressing. If successful, this type of blade will have equal shear strengths in two directions, will save veneer and resin, and will be adaptable to the Hamilton standard hub.

 

F. Hills and. Sons, Ltd., is also considering the use of Zebwood, a veneer-plastic composite for propellers.

 

Molded Components, Ltd., have molded experimental blades of impregnated veneers pretailored to shape. Each of the two faces of the blade consists of nine continuous plies, a feature that avoids excessive exposure of end grain and glue lines and provides a skin running the full length of the blade.

 

None of the wood blades now in production can be fitted satisfactorily to the Hamilton Standard hub, which requires a hollow root. They are all used with the Rotol hub of British manufacture. A threaded conical ferrule is used on all wood blades and is cemented in place with "Semtex," a mixture of Portland cement and rubber latex. Considerable interest has been shown in the new lag-screw retention developed at Wright Field.

 

Although Jablo and Weybridge blades are balanced against masters, Hydulignum blades are still furnished only in matched sets and are not interchangeable.

[Ray_W]

6 minutes ago, 303sqn said:

THE USE Of WOOD FOR AIRCRAFT IN THE UNITED KINGDOM

Report of the forest Products Mission June 1944

Great 1944 summary on UK wood prop blades. I had not seen that before. 

[72modeler]

@303sqn,

 

That is an amazing post! Very, very interesting! Making those blades was incredibly labor intensive! Thank you for sharing this with us. I guess we exported spruce and birch and other suitable wood types to the allies in WW2, as I don't recall reading about much usage of wood props by the miltary except for liaison and light twin engine aircraft.  

Mike

[Work In Progress]

Most of the timber used in UK aircraft production during WW2 came from Canada. So did a lot of the wood used for war work in the USA. 45% of British Columbia's timber production was exported to UK during WW2, and 25% was exported to the USA.

Of course they also used a lot themselves making aircraft and other items, including plywood for packaging of all kinds of war materiel. Packaging alone generated a huge requirement for timber during the wartime years.

Edited April 9, 2020 by Work In Progress

[Corsairfoxfouruncle]

Hello everyone... So very sorry to be a pain in the Rump, I have a new question regarding the pink FR.Mk.IXc’s. Did they use slipper tanks for there missions, I cant see anything in the photo’s. However I am looking for a confirmation of either yes they did or no they didn't ? Thank you in advance. 

[Steve 1602]

36 minutes ago, Corsairfoxfouruncle said:

Hello everyone... So very sorry to be a pain in the Rump, I have a new question regarding the pink FR.Mk.IXc’s. Did they use slipper tanks for there missions, I cant see anything in the photo’s. However I am looking for a confirmation of either yes they did or no they didn't ? Thank you in advance. 

Hi Dennis - found this photo which shows a fuselage tank (not the slipper tank) fitted to a pink Spitfire (I’m making an assumption that it is an FRIX).

link is:

https://ww2aircraft.net/forum/threads/spitfire-fr-ix-iff-radios-carried.16552/#lg=post-446663&slide=1
 

Doesn’t help with the yes/no to slipper Tanks unfortunately, but does show another potential option!

 

Steve

Edited April 10, 2020 by Steve 1602

[fastterry]

I think you'll find that the brown round thingys just visible in the hanger are the fronts of the torpedo type drop tanks used towards the end of the war. The photo in the link posted by Steve shows the rear of the tank and it looks like a dark colour.

TRF

[Corsairfoxfouruncle]

21 hours ago, Steve 1602 said:

Hi Dennis - found this photo which shows a fuselage tank (not the slipper tank) fitted to a pink Spitfire (I’m making an assumption that it is an FRIX).

link is:

https://ww2aircraft.net/forum/threads/spitfire-fr-ix-iff-radios-carried.16552/#lg=post-446663&slide=1
 

Doesn’t help with the yes/no to slipper Tanks unfortunately, but does show another potential option!

 

Steve

 

20 hours ago, fastterry said:

I think you'll find that the brown round thingys just visible in the hanger are the fronts of the torpedo type drop tanks used towards the end of the war. The photo in the link posted by Steve shows the rear of the tank and it looks like a dark colour.

TRF

Thanks Steve & Terry those look good as an option. Steve the plane I'm building is Red X, it happens to be the proceeding photo, so I think its not unlikely that mine also carried a drop tank. Terry thanks I had been trying to figure out what those were. I thought no way on bombs, but maybe lights on the floor of the hanger to work by at night with the windows blacked out. But tanks is a way better possibility/option. So are they a rubbery brown/black in color ? 

Edited April 11, 2020 by Corsairfoxfouruncle

[fastterry]

Hi Dennis, there are a number of photos and profiles in vol.2 of the 2ndTAF showing the tanks on normal DFS spitfires and they seem to be in MSG to match the underside. The tanks are similar to the paper tanks on P-51's but I don't think they are paper. I googled 'RAF torpedo drop tanks for spitfires' and apart from a million photos not directly related to the query there is a photo of a tank being made in the UK by women tradespeople. Luck would have it that Eduard Brassin have the tank in both 1/72 & 1/48. Colour wise it's a guess, maybe 'pink' brushed over undercoat, possibly red dope. Nobody can prove you're wrong either way.

TRF 

[JoeSmith]

On 4/9/2020 at 12:39 AM, Ray_W said:

Apologies. Yes. Should be ...

 

 

 

I think you will find that this is not actually where the engine crankcase breather exits.  The location indicated by the arrow in the picture is where the outflow pipe from the coolant header tank relief valve exits through the side of the engine cowl.  

 

Cheers

 

Joe