Jump to content

DH.50 info


Anthony in NZ

Recommended Posts

Who's silly idea was a quick research project? I've even waded through tales of DH.50A passengers sharing the cabin with chickens. It seems that the early 50 was a three passenger setup and the 50A was for four passengers.

I can hardly find my printer!

On the plus side I think I've located the elusive inches and the jigsaw is fitting nicely. I just hope that the dog hasn't had the last piece.

 

John

 

IMG_2110_zps5dmd4p1g.jpg

  • Like 4
  • Haha 1
Link to comment
Share on other sites

So just as I feared, the dog has eaten some of the pieces. The only reference I can find to the larger wingspan and the wider centre section is in British Commercial Aircraft (Ord-Hume).  A.J.Jackson first mentioned the splayed out struts, but this is in relation to the larger, or is it longer cabin of the 50A.  I can find no evidence as to the larger wing span or the 'wider' centre section and I think the struts splay is in fact in relation to the added cabin length.

I have also had some disquiet about the shape of the rudder and it's suggested origin, in comparison with photos, then I had a thought.. The DH 42. Dormouse might be the answer...

 

I've got to go shopping, more later.


 

John

  • Like 4
Link to comment
Share on other sites

So whats the Dormouse, got to do with it (only the British could name a reconnaissance fighter after a fluffy dozy mammal).  Again blame Mr Ord-Hume, because the only comment on the possible origin of the stripey prototype rudder comes from his B.C.A. book, ie the DH 9 rudder.  Don't get me wrong, I like his books very much, but we can all make mistakes. I, on the other hand, I think the entire tail end is in fact that of the Dormouse/Dingo, as is the rubber in compression under-carriage, wheels. and DH's differential ailerons.

My curiosity aroused, and throwing best practice to the winds, I scaled up the three view in Putnam's DH Aircraft, traced it in CorelDraw 12 and bingo, the narrow chord tailplane and elevators, fin and rudder fits the DH 50 empenage like a glove! 

Sir Geoffrey seldom missed a trick and so I posit that both the Dormouse and the DH 50, which were contemporary 1922 designs shared some common parts, with the DH 50 using the ubiquitous DH 4/9 wings. The Dormouse, as a military type, went for the new biplane thinking of having a smaller lower wing with a neutral incidence which only produced lift and therefore drag at the low speed end of the flight envelope.

 

Back to the task in hand. I am happy that the wings are mildly modified DH 4/9 structures and the tailplane and fin can be altered from a DH.4/9. I also think that the 50 and 50.A fuselages are very similar with the latter's cabin having a small increase in length (7.5") aft of the lower rear main spar. Some Australian built ones might have had a small increase (2.5") in fuselage width, hence a wider centre section. but at this time I'm not sure.

 

It would appear that the lifting roof of the cabin is lined with a pale material and one, a Western Australia Airways built 50.A, had the interior lined with brown leatherette material. ( K.R.

Meggs in Australian built Aircraft).

 

John

  • Like 3
  • Thanks 1
Link to comment
Share on other sites

Wow, John, you are totally excelling yourself here mate!  There will be no question now after reading all these findings that I am going to convert my WnW AMC DH.9 into this DH.50.  I am getting my head around all this I think.... The NZPAF photo I posted at the beginning of this discussion is a .50A, is that correct?

 

Keep up the great work, you have several of us captivated, including a couple more Kiwi's that aren't members!

 

Cheers Anthony

 

  • Like 2
Link to comment
Share on other sites

Anthony,

Yes the NZPAF one is a DH 50.A. I'll finish this and someone will say, "I've got the manual". However DH Manual illustrations aren't too clever as all the problems with the Fox Moth centre section tank, stem from the drawings in the Manual and hence the drawings in Flight and then Aeromodeller et al.

 

Thanks for the comments.

 

Cheers

 

John

Link to comment
Share on other sites

2 hours ago, Anthony in NZ said:

couple more Kiwi's that aren't members!

& one that is though I won't be using any WNWs kits, mine will be in 1/72 come the day & as such I'll be able to take a few more liberties than Anthony can. :)

Thanks John for your amazing work, I've long looked at that photo of the RNZAF example & thought "if only" for my intended RNZAF collection. Now I'm thinking much more positively about it.

Steve.

  • Like 2
Link to comment
Share on other sites

3 hours ago, John Aero said:

It would appear that the lifting roof of the cabin is lined with a pale material and one, a Western Australia Airways built 50.A, had the interior lined with brown leatherette material. ( K.R.

Meggs in Australian built Aircraft).

John

Somewhere in my files I believe I have an old 1920s Australian DuPont 'Fabrikoid' sample book. Fabrikoid was DuPont's trade name for their artificial leather.

Fabrikoid was pretty ubiquitous in the 1920s so may have been used in the Australian built 50.A.

 

Tim

  • Like 2
Link to comment
Share on other sites

Thanks Tim, I would think that you're right, though I've never heard of the trade name.

 

In regard to the engines and cowls used on the 50/50.A , I understand that there was only one 50.A built which used the 50 radiator. This was G-EBQI which stayed in Britain.  All the others used the flatter deeper type, including the NZ example. 

 

I believe that Cobham's 50J was a short cabin type but the other 50J's were long cabin types.  I have also found reference to the A models having the under-carriage moved further forwards. I suggest that this was achieved in the same manner as on the Wapiti, in that the anchorage point remained the same but the front radius struts were shortened thus moving the wheels forward.

 

John

  • Like 2
Link to comment
Share on other sites

I made it to the Library and found the journals (Automobile Engineer) but sadly, nothing on the DH50.

I checked all the available journals that might have been relevant (1923 to 1933)...however, I suspect that my memory was faulty (it happens!) and was of the article about the DH61 which it covered in some detail.

Lots of other useful articles: DH60 (Cirrus), DH60M, DH66, two on the Jupiter engine, power installation in the DH54, DH58 and Supermarine Sea Lion, Bristol Cherub etc as well a s host of stuff on cars that also interest me.

John, Anthony, let me know if you would like copies.

I will keep searching.

And, John, please keep up your great work; I too appreciate your efforts.

David

  • Like 1
Link to comment
Share on other sites

3 hours ago, stevehnz said:

& one that is though I won't be using any WNWs kits, mine will be in 1/72 come the day & as such I'll be able to take a few more liberties than Anthony can. :)

Thanks John for your amazing work, I've long looked at that photo of the RNZAF example & thought "if only" for my intended RNZAF collection. Now I'm thinking much more positively about it.

Steve.

Yes mate, there is little one can get away with in 32nd scale!  

  • Haha 1
Link to comment
Share on other sites

56 minutes ago, David M said:

I made it to the Library and found the journals (Automobile Engineer) but sadly, nothing on the DH50.

I checked all the available journals that might have been relevant (1923 to 1933)...however, I suspect that my memory was faulty (it happens!) and was of the article about the DH61 which it covered in some detail.

Lots of other useful articles: DH60 (Cirrus), DH60M, DH66, two on the Jupiter engine, power installation in the DH54, DH58 and Supermarine Sea Lion, Bristol Cherub etc as well a s host of stuff on cars that also interest me.

John, Anthony, let me know if you would like copies.

I will keep searching.

And, John, please keep up your great work; I too appreciate your efforts.

David

Thanks Dave....don't go side trackin me now LOL.  That stuff sounds very interesting indeed!

 

John, that totally makes sense that they 'rotated the u/c through its rear anchor point to bring it forward as there was probably a good structural member/weld/join that would take the stress of landing back there.

Link to comment
Share on other sites

14 minutes ago, Anthony in NZ said:

John, that totally makes sense that they 'rotated the u/c through its rear anchor point to bring it forward as there was probably a good structural member/weld/join that would take the stress of landing back there.

I'm guessing it would be more than just shortening the front struts but rather a slight shorten of the front struts & slight lengthening of the rear ones to steepen the front strut angle so as to maintain propellor ground clearance?

Steve.

  • Like 1
Link to comment
Share on other sites

6 hours ago, stevehnz said:

I'm guessing it would be more than just shortening the front struts but rather a slight shorten of the front struts & slight lengthening of the rear ones to steepen the front strut angle so as to maintain propellor ground clearance?

Steve.

Good point Steve....we shall await John's findings and/or confirmation!

  • Like 1
Link to comment
Share on other sites

Steve,

On the Wapiti, only the front u/c struts were changed when the change between the heavier un-geared and geared Jupiter's occurred. The arc of the main leg is so small it makes little difference to the  propshaft overall height. However on the Wapiti they also changed the wing stagger which did involve new C/S struts. I have the stores numbers for all of this.  Unlike the Wapiti it appears that the tail moment arm of the DH 50.A was slightly increased. when the cabin was extended. Huh ho see the next post!

 

David M, Interesting stuff.

 

John

  • Like 1
Link to comment
Share on other sites

I'm now at an impasse with this "well known" aeroplane. I'm having to rethink at what point the two main versions differ in length. The reason is I looked at the dimensions for DH 50 fitted with floats and the same for the DH 50.A  They are the same overall length, so if the tip of the Short's floats to the tip of the rudder is the same, then the difference to the two Puma installations must lie somewhere forward and not in the rear fuselage.so no tail moment arm change. A further clue is that the wheels were moved slightly forwards on the A. This usually indicates a C of G change such as the engine and firewall being moved forwards.  Again a la Wapiti. This would also facilitate the lengthening of the cabin. and the increased splay of the cabane struts. While we're in this area I noticed that the cabane rigging wires are only on the port side. Obvious, or you can't access the cabin.  I have found a mention that the A had a small forward cabin bag stowage. Presumably where the chickens lived.  Grrr.  My hair's grey enough.

 

The Curator of the QANTAS Longreach Museum has kindly taken some photos of their DH 50 Cabin mock-up so I have a bit more idea of the interior and it confirms that there's another cheapo DH deck chair, like the one in the Fox Moth.

 

I just glanced at one of my test drawings and some of the A3 printed out photos, I just realised that there's no "body" (insert any other word that comes to mind), standing in front of the area of interest. I think I might just see a chink of light. Of course we're only talking of 7".

 

John

  • Like 1
Link to comment
Share on other sites

Hmmm, thats very interesting John, and that totally makes sense in relation to the u/c mod if the extra length is forward of the cabin...you are making my hair go greyer too, LOL

 

Keep up the awesome work!  I see your post on Key, smart move as there are some pretty knowledgeable guys there and might have access to unusual stuff.

 

Cheers Anthony

Link to comment
Share on other sites

As any followers of this post might have guessed, I was getting pretty frustrated by trying to find what was throwing out all my calculations. It's easy to get in a spin when confronted with a number of dimensions in various books especially when there is no explanation of what the source is.

 

I mentioned in my last post that the tip of floats to tip of the rudder dimension, ie overall lengths for floatplane DH 50 variants, was quoted in British Commercial Aircraft (Ord-Hume) as common to both the DH 50 and the 50.A, but also the 50.J's, so if I believed these figures it suggests that all the rear fuselages were common from the first to the last (Given a standard Short Bros float fit). Therefore any difference in the Landplane overall lengths had to be in the nose area and forwards of the front wing spar. So the missing 7" difference must appear somewhere.

 

All the various drawings do exhibit close similarities, but I chose the relatively simple Australian source, de Havilland fuselage side view, as my common base in conjunction with the dimensioned drawing of the prototype from a 1923 Flight. Once I had reasoned that the tail end was most likely that of the DH 42 Dormouse and that it agreed with the Flight drawing dimensions. Flight had a peculiar habit of dimensioning the plan view by giving a dimension from the top wing trailing edge to the tailplane leading edge. Useful but dangerous as my old friend the Wapiti proved, that if the wing stagger is changed then this dimension is misleading and as lots of Wapiti modellers and drawings never allude to, unless you have read the AP.

I was lining everything up for my overlays and on screen for the various versions but try as I might the nose differences were never 7"inches. It occurred to me that if the rear fuselages were to be taken as common then the T/e to L/e dimension should fit.

This T/e to L.e dimension for the DH 50 is 13 feet and although all the drawings showed the same wing stagger the dimension was always wrong, even on the DH company drawing, on my overlays and on the computer.

 

It was only when I decided to move the wing cellule back three inches on my drawing and ignore the printed base drawings did everything slip into place. I now know exactly where the elusive 7 inches fits.

 

I think I can now put together a creditable set of drawings for this "well known aeroplane".

 

John

  • Like 5
Link to comment
Share on other sites

Time for another update on this odyssey. Today I received a very useful photograph from the QANTAS Heritage Collection, of a DH 50.A fuselage under construction. It's particularly useful as I can see the shape of many of the metal fittings and brackets  for such as the U/c, cabane struts, and lower wing mounting brackets former positions etc. 

 

I realize that this might seem over the top to some, but their positioning and alignment tell me a lot of how the underlying structure fits together and the relationship of various parts.

 

The main cabin was at best a pretty spartan place. The rear seat to take two people was a box bench seat against a sloping ply bulkhead. there was probably a cushion but no seat belts. The front seat was a strange affair rather similar to a wide deck chair suspended  between two tubular poles athwart the fuselage. The rear seat in most of the Fox Moths by the way was of a similar type. The drawings for the interior of the Cobham DH 50 are no real help to the standard commercial aeroplanes.

 

The fuselage was totally plywood covered and the cabin interior was double skinned from the floor up to the bottom of the bulging side balconies. the sloping structural side intercostals are visible on the inside of the  bulges. Many of the interiors appear to be painted white or a pale blue (that is until I know for certain).  The port and starboard sides of the fuselage were quite different. On the port side there is a long wooden cable and pipe duct running under the balcony from the side of the pilots cockpit to the side of the engine bay. The cabin roof and side windows opens only from the starboard side and is hinged just off centre of the cabin top. Aero (Czech) built cabin tops are opposite due to the engine exhaust running down the starboard side. The skylights in the cabin tops and doors vary from round, oval to rectangular.

The fuselage section changes quite radically from the rear cabin bulkhead to the bulkhead behind the pilots seat.  Certainly one late build 50 A was fitted with DH 9a wing slats and doughnut tyres.

 

Variants:  The Cobham Jaguar powered DH 50 is of the short cabin type  and it differs quite a lot from the standard Puma powered airliners. The long cabin DH 50 A's are all fairly similar except for the propellers which can be of the two bladed type or lapped four blade or even normal four blade props. The The Jupiter powered DH 50 J conversions of the Australian DH 50 A's were of the long cabin type but again some machines had double wheels fitted.

I have evaluated the Aviation News drawings and they are simple and there are errors, but they will serve to make a less detailed model. The outer wing strut spacing is one main point.

 

For my DH 9 reference I'm using the old Maurice Brett drawings from Scale models as I think that they are quite good.

 

 

John 

 

  • Like 3
Link to comment
Share on other sites

Great results John!  What a great find with the photo from the QANTAS team.  I am pleased to hear that the interior is spartan, as the fuse sounds like a big job in 32nd scale.  But still sounds very do-able!

 

Exciting stuff, thanks for all your hard work!

 

Cheers Anthony 

Link to comment
Share on other sites

I just read and thoroughly enjoyed this thread.

 

What a great example of teamwork, superb research all round!

 

Hood luck with building this in 1/32, I really hope that there will be.a WIP here on BM 

 

i have a passion for all

thkngs De Havilland; like @stevehnz I would love to make a DH50 (in my car, a float variant) in 1/72..

 

The starting point is interesting to consider. I don’t yet have the confidence to completely scratch build something, therefore I prefer to start with something, anything, as my chunk of rock from

which to carve the David, (or more likely, the Homer - Simpson, even if there’s hardly anything left of the original kit/s at the end of the build. 

 

Maquette, the Russian manufactured make a Polikarpov R-1 , the Russian DH-9a, but possibly an Airfix DH-4, Blue Rider DH-9 fuselage and a razor saw and lots of cups of tea would be a better starting point for a DH-50 in 1/72?

 

I don’t want to go off topic but I’m in Canberra, should anyone want photos of the DH-9 here at the AWM, I would be happy to help.

 

I’m also trying to amass materials for the Hispano built Spanish DH-5’s. I’m almost happy with plans, although the ones I have are very small and lacking in detail.

 

I’m lacking clear photographs and/or drawings/plans of the engine/cowl area; the area most different to that on British made examples.

 

Great stuff on this thread, a thoroughly enjoyable read and already a great resource 👍 

 

Best regards

TonyT

  • Like 2
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...