The Gordon Bennett Air Race 1911 Part 2: Bleriot XXIII

[lone modeller]

Evening All,

The second subject for the Gordon Bennett racers of 1911 is the Bleriot XXIII. This is causing me a few problems because only two of the type were constructed, (they were built as racing aeroplanes), and apart from a handful of photographs, I have little information about them. There are no drawings that I am aware of. I have a dimension for the wingspan, (17 feet), which is incredibly narrow, and a wing area, so I think that I can calculate the chord. Sources state that the wings of the original design were longer but were reduced by approximately 1 metre before the Eastchurch race. I also know the length of the aircraft and that they were powered by 100 hp Gnome Double Omega engines. Photographs show that the original wingtips were rounded, but for the race they were square. The fuselage seems to have been developed from the earlier two seat XXI, although the latter had a much shallower fuselage, especially at the rear. Both types had a large horizontal tail surface and a rudder but no fin, although the shape of the rudders was different. I am therefore making my own drawings and writing the assembly instructions at the same time.... I make no claims to accuracy of these models - they will be the best that I can do given the source material available. However I am pretty certain that there is nobody who can challenge the overall shape even if some details are not 100% accurate. I am making two models to represent the two aircraft but as with the Nieuport IV I am only illustrating the build of one model: I will show photographs of both when they are complete.

I have started as usual by cutting the wing blanks from 30 thou card bent in hot water in a pipe with 10 x 20 thou Evergreen strip for ribs. The strip was sanded almost flat and the Mr Surfacer added to smooth the edges. I have made the rudders in the same way from flat card. The fuselage sides, top and bottom were cut from 30 thou card and pieces of scrap plastic added to keep the joints square. I added some 10 x 20 thou strip to represent the frame in the cockpit area, I have cut a floor and painted it wood, and made a control yoke from 20 thou and 80 thou rod. The engines were made from thick sprue for the crankcase with 30 thou rod for the cylinders. I have painted this assembly but not added the push rods yet:



The seats were made from scrap card for the base and 10 thou card with holes drilled for the back. I am carving the propellors from hardwood using plans from the DataFile no 108 of the Bleriot XI at War. I cut the wood into strips of suitable length, marked on the shape of the propellor and filed the shape that I wanted. I will add bosses later from thin card:



I shall use the DataFile plans to make the undercarriage and to help with the shape of the fuselage as the XXIII was clearly derived from this earlier design.

Thanks for looking: more to follow when I have made more progress.

Stephen.

[RichieW]

Good start Stephen, building a model from just a couple of photos sounds like an interesting challenge. One I am sure you will rise to in fine style.

Richie

[Rookie]

I am absolutly mindblown by your ability to make such great historical and detailed models with so little resources. 

And your build speed keeps amazing me Stephen.

Hats off!

Kind regards
Willem

[Boch]

Creating from scratch. The highest degree of modeling. I'm keeping my fingers crossed and following with great interest.

Lukasz

[RAGIII]

Excellent start as always Stephen. Your Scratch building abilities continue to amaze!
RAGIII

[DaveB]

Another one of your interesting types, Steve -

and another tractor to boot!!

Regards

Dave

[lone modeller]

Evening All,

Many thanks to all of you for your very kind comments and encouragement which are much appreciated.

Recent progress has been more glacial than normal on account of some important family events and a combination of stupidity and experiment on behalf of yours truly! I assembled the fuselage parts illustrated in the last post in the usual way: glue one side to the bottom, insert internal bracing, and allow to dry out:



Then I added the second side and upper fuselage rear, and moulded the front part using an old set of moulds from a Bleriot XI scratch build of a decade ago, only to discover that I had made two errors: first the fuselage was too narrow by approximately 1.5mm which matters because the engine has to fit in the front. Secondly, after much scrutiny of photographs, particularly one of le Blanc taking off at Eastchurch, I decided that the rear end of the fuselage was not blunt as I had modelled it, but probably tapered towards the elevator. I am not certain of the detailed shape of the rear of the fuselage, so I am using modeller's license to interpret a rather poor quality photo.

I decided to start again and make up new fuselage parts, including a new mouding for the upper fuselage front. However because of my sheer incompetence I managed to mis-measure (twice!) and cut once the width of the fuselage so that the new part was even narrower than the first attempt!! A third attempt succeeded in producing a pair of fuselages which were of the correct width and tapered in the horizontal plane at the rear. In addition the new upper part for the front fuselage fitted properly at last:



The difference between the fuselage shapes of the first and final attempts are shown here:



The engine was mounted at the front on a cross brace which I cut from 20 thou card:



The engine had a piece of plastic rod inserted through the centre with a small length extending to the rear to allow a small piece of plastic card to be attached that could be glued on to the fuselage sides. The front and rear mounts hold the engine in place. I cemented the cockpit floor with the  seat and control unit into the fuselage, and the oil and fuel tank in front of the cockpit opening - they were cut from plastic rod:



The upper fuselage moulding was cut and filed to shape and the cross bar which held the undercarriage legs added from strip. I placed the new part of the fuselage structure to allow a photo to be taken: the cross bar will be painted before I cement the parts together:



The grey on the front of the moulding is filler: a small dimple occurred in the moulded part which had to be filled and smoothed with Mr Surfacer. 

Thanks for looking.

Stephen.

[RAGIII]

Really looking awesome!
RAGIII

[kensar]

Good progress after the mis-starts.  I have found it's best to start with the engine and cowling first and then go on to the fuselage to ensure that everything fits.  At least the engine and cowling are available for test fits as the fuselage progresses.
But I'm sure you know how to build a model!   

[RichieW]

Lovely work Stephen. Commendable patience too, I often find the decision to start again very hard to make so it's good to see you deciding early.

The model looks beautiful with the engine mounted, thoroughly convincing!

Richie

[FAf]

Great work! As awe inspiring as always.
/Fredrik

[RichieW]

Having seen these on Saturday I was struck by how tiny they are and how much detail you have crammed into them even in God's own scale. They already look like little jewels and will be stunning when finished. I'm looking forward to seeing them again with a little more work carried out.

Richie

[lone modeller]

Evening All,

Many thanks Rick, Ken, Fredrik and Richie: your comments are much appreciated. Richie: the One True Scale does mean that the model is rather small but it also means that I do not get bogged down in endless details!

The undercarriage arrangement for the early Bleriot designs was far from simple - as I found when I scratch built a Bleriot XI Penguin some years ago, and as anyone who has tried to build a kit of the type will know. I wanted to start the undercarriage before adding the wings, so made the supports under the fuselage from plastic strip, the under crossbar form strip and the oleo tubes on the sides from thin rod. I drilled the upper and lower horizontal bars so that I could insert the rods: the unit is not cemented in place yet - just the fuselage supports:





Now I could return to the wings. I have not been happy with the original wings that I made from the very start as they do not look anything like the wings in the photographs. The problem was that the wings that I made are too short and the chord is too wide. I had used the published dimension for the "span" which was 17 feet (approx 5m). I studied a photograph of one of these machines with a figure in the foreground and used the latter as a scale. From my (very) crude measurement it was clear that a single wing was approximately 8 /12 feet long. I used another photograph and again using a crude method measured the ratio of span of a single wing and chord: the result was approximately 2.9:1. When I drew a plan with a single wing scaled at 8 1/2 feet with a chord 1/3 of the span, I had a shape that looks very close to that seen in the photographs. Compare this with the shape that I had originally made:



The new wing shape is in the top of the photo. A quick calculation of wing area using the new dimensions came close to that published in my source. Clearly the span of the wings was correct only if the fuselage gap was omitted: then the "span" and wing area match the published data. Clearly the source made a mistake with "span" which I take to mean the distance between wing tips including the fuselage.

Now I could get the correct number of ribs on each wing, (as per the photographs), and attach the wings to the fuselage:





Painting and numbers will be applied next.

Thanks for looking.

Stephen.

[RAGIII]

I am glad you were able to work out the difference as the wing to fuselage looks awesome!
RAGIII

[RichieW]

Great detective work Stephen, the new wing looks much more likely to me.
That undercarriage must be truly miniscule but you've done a very neat job on it. Looks fantastic. Looking forward to seeing the colouring in done.

Richie