Mclaren M23 1976 - The Details

[Hacksaw]

Mclaren M23 1976 - The Details

Anorak time. Over the years I have been collecting reference material for the Mclaren M23 which I intended to build using the Chevron trans-kit. Any Members of the Forum interested in making their model of the Mclaren M23 to reflect a particular race may be interested in the following notes. If anyone has contradictory or additional information please do add it to the thread.

M23 Roll Over Bar
During the course of the 1976 season the Mclaren team raced the M23 with two different styles of rollover bar, in the simplest form it can be said that Jochen Mass raced with the lower rollover bar and James Hunt being taller raced with the higher rollover bar. However things are not that simple James Hunt had two different configurations of cross bracing to the rollover bar and both drivers had the rollover bars and cross bracing in bare metal or chromed at different times during the season. My notes on these differences follow with links to the images that I have used as a reference; these links may also be used to verify other details that I list further on in this note:

Mass - Low bar, low bracing, not chrome venue not known http://imcdb.org/vehicle_181667-McLaren ... -1976.html

Mass - Low bar low bracing not chrome F GP
http://www.racingsportscars.com/f1/1976 ... 04-012.jpg

Mass - Low bar low bracing not chrome D GP
http://www.fotocommunity.com/pc/pc/pcat ... y/12003584


Hunt - High bar high bracing, not chrome Dutch GP
http://www.racingsportscars.com/f1/1976 ... 29-011.jpg

Hunt - High bar low bracing, not chrome Dutch GP http://picasaweb.google.com/lh/photo/Ib ... KN2MmL57ZA
And
http://b.f1-facts.com/ul/a/3384
http://www.f1-facts.com/gallery/r/276

Hunt - High bar, low bracing not chrome Belgian GP
http://www.diariomotorsport.com.br/wp-c ... pany_2.jpg
And
http://www.diariomotorsport.com.br/wp-c ... pany_3.jpg
And
http://www.racingsportscars.com/f1/1976 ... 16-011.jpg
With Mass’s low roll bar car in the background.

Hunt - High bar low bracing not chrome GB GP http://www.zimbio.com/pictures/oS7d6uUh ... sz76vCBJ7l

Hunt M23 - High bar low bracing not chrome GB GP (Page 67 Post 2657)
http://forums.autosport.com/index.php?s ... 67&st=2640

Hunt - High bar high bracing not chrome D GP
http://www.racingsportscars.com/f1/1976 ... -011_T.jpg

Hunt - High bar low bracing chrome Canadian GP
http://picasaweb.google.com/samjr469/Be ... 5484634802

Hunt - High bar, low bracing, chrome USA GP http://www.flickr.com/photos/steve-1828/5095173538/

Hunt - High bar low bracing chrome Japanese GP
http://forthebestglory.tumblr.com/
And
http://shop.simonlewis.com/ekmps/shops/ ... 1743-p.jpg

Driver not known - Roll bar not chrome, bracing chrome, Monaco 1976
http://www.motorsportretro.com/wp-conte ... Monaco.jpg

Villeneuve - High roll bar low bracing not chrome GB GP (1977)
http://i183.photobucket.com/albums/x207 ... illeg1.jpg



M23 Other Details
Mass Monaco Link: http://www.fotocommunity.com/pc/pc/pcat ... ay/6784834
This image shows a number of details that were relevant to the M23 during the 1976 season these are:

Airbox - The low profile airbox first appeared at the Spanish GP, but the cut down version seen in the link above only appears to have only been tried at Monaco, Mass and Hunt also tested at Monaco without the airbox but with the triangular air filter above the engine injectors. (From what I have fond both drivers raced with the new low airbox but I have not been able to make a definitive verification of this.)

The inside of the low airbox was either left a creamy off white natural glass fibre color or painted black, refer to the above links.

Kickups - Attached to the rear side pod extensions of the bodywork, in front of the rear wheels and tested at Monaco (I have no information of them being used anywhere else). Note also the change in the line of the red paintwork around the kickup.

Cockpit Suround - The lip of the cockpit surround where it and the tinted windscreen meet was painted different colours on different cars in this image the lip is white, on other cars the whole cockpit surround is red and on some cars the lip also has a black line (at a guess a double sided tape of some type).

Windshield
From what I have found out Mass competed with the same windshield arrangement throughout the 1976 season as seen here:
http://www.fotocommunity.com/pc/pc/pcat ... y/12003584

Note how the top of the windshield seems to be slightly lower at the front than the rear.

Hunt seems to have had used three styles of windshield during the 1976 season, seen most often is the “standard” arrangement similar to that used by Mass but with the top an inch or two higher. On occasions the windshield featured from the driver’s hands forward a near vertical lip on the top edge similar to the M16 and M24 style of windshield. At the rear the windshield tapered down over the last two or three inches to meet the top of the cockpit surround / windshield support. At the British, Dutch, German and Canadian GP’s an additional section was added to the front of the windshield extending it towards the driver. The tinted color of the windshield varied from a deep yellow to clear. (These variations may be caused by differing lighting conditions rather than the colour of the windshield but the extent of the differences in colour may indicate otherwise, see the links above in the Roll Bar section to verify these statements.)

These links may also be of use:
Link to M23 Hunt cockpit dash and windshield extension.
http://www.fotosearch.com/IST539/1634748/

Link to M23 Canadian GP windshield extension.
http://www.diariomotorsport.com.br/wp-c ... ompany.jpg

Link to M23 Hunt Top lip to windshield
http://www.f1-photo.com/Search/M23+Hunt ... unt/p23x16

Link to M23 Hunt taper to rear of windshield
http://www.f1-photo.com/Search/M23+Hunt ... unt/p21x16

And GB GP
http://www.zimbio.com/pictures/oS7d6uUh ... sz76vCBJ7l


Oil Radiators - At the start of the 1976 season the M23 raced with the oil radiators located in the side pods (exact location not known but not with the air opening in the side of the rear side pod extension). At the Spanish GP Mass retained the oil radiators in this position while Hunt’s M23 had the oil radiators moved to the side pod extensions immediately in front of the rear wheels where air openings were let into the side pod extensions. Following the protest at the Spanish GP Mclaren decided to race with a totally legal car and moved the oil radiators to the rear of the car (possibly mounted in a similar manner to the 1973/4 car) this setup was used for the GP’s at Belgium, Monaco and Sweden, the oil radiators were moved to the rear side pod extensions for the French GP and remained in that location. (Information from Motor Sport August 2002 an article entitled “Learning New Tricks”.)

But having said all that there are these two contatradictory images:

Belgian GP - Note opening in rear side pod extension.
http://www.diariomotorsport.com.br/wp-c ... pany_3.jpg

And

Belgian GP - Note no opening in rear side pod extension.
http://www.diariomotorsport.com.br/wp-c ... pany_2.jpg

Rear Brake Cooling Duct - Periscope type rear brakes located above the back of the cam covers, this was a carryover from the previous season and changed sometime in 1976 to the low level ducts that collected air from behind the oil radiators that were used from the French GP onwards.

Front Brake Cooling Duct - An extra cooling duct was located on the top of the front upright to provide additional cooling, this was used on circuits where greater breaking forces were applied.

Twin Rear Wing - Not visible in the image linked above of Mass at Monaco (but seen in the July 1976 centre picture spread of the Monaco GP in Motor Sport and here:
http://www.f1db.com/forums/printthread. ... ge=4&pp=40).
Mass tested a twin rear wing arrangement consisting of a similar main rear wing and two smaller wings either side of the gearbox. Both wings had separate endplates and these (in the Motor Sport images) were painted red for the top end plate and white for the bottom endplate.

Lower Front Wishbone - (I have very little to add to this conundrum were they tubular or fabricated? Copyright prevents me from posting images from unknown sources that I found on the internet some time ago, that are from the period are not that clear. This image: http://www.geting.se/viewimage.php?image=220472-42.JPG
shows Mass leaving the pits with an unmarked low height airbox where the fabricated lower front wishbone is just visible, this could have be taken during early season testing, possibly at the Spanish GP according to the website. Most annoyingly two of the three cutaway drawings that I have of the 1976 M23 manage to obscure the lower front wishbones while the third seems to show a tubular lower front wishbone.

(In the February 1975 edition of Motor Sport the report for the Argentinean GP noted that) “....M23/9 being a brand-new car for Fittipaldi featuring a narrower rear track and brand-new front suspension, similar to the BT44B set up.....” (i.e. fabricated lower front wishbones?)

(The Scale Models magazine March 1977 edition has a drawing of the 1976 M23 that appears to show a fabricated lower front wishbone.)

(I have photocopies of images from the British and Canadian GP’s that show Hunt’s car with tubular lower front wishbones with a small infill fillet at the outer end.)

From the Alistair Caldwell Web Site:
http://www.alastaircaldwell.com/1975_hunt_joining.shtml
James became our driver in ’75 and we took him to Silverstone and – being England – it snowed. We realized he was so long in the legs that we couldn’t fit him in the car. We used to call him Quasimodo because he was like a hunchback with very long legs. We had to cut the front of the car out and move the pedals forward. He also had to cut off the ends of his shoes to make his feet as short as possible.

Regards,

Hacksaw

[ewestra]

Thanks a million Hacksaw, this will do me a lot of good since I'm building the 1977 Long Beach car of James Hunt. Do you have pictures of this car. I haven't found many pictures of this car. Some help would be appreciated on wheels and color of the windscreen. Maybe you can help me. Again thanks for your effort in sharing all this info and pictures.

Eric

[Flemming]

Exellent roundup of M23 changes!

Best regards

Flemming

[Hacksaw]

Hello Eric ,

Apologies for not getting back to you earlier about the 1977 M23 but I have been away from my computer for a couple of weeks but I am back now.

This link shows Hunt’s car in South Africa:
http://lh3.ggpht.com/-ScTk7GL9nKg/SsnIp ... 252529.jpg

Note:
• The higher windshield,
• The ICL (I think) advertising on the front wings,
• The roll bar which is not chromed,
• The bracing to the roll over bar has changed from an “X” to an inverted “Y”,
• The white top lip to the cockpit surround.

This link:
http://www.flickr.com/photos/marcmelander/2916122050/
Shows an image of a restored M23 which is fitted with the 1977 style rear anti roll bar which is behind the drive shafts and passes through both the rear wing pylon support plates. Note that while a rear light was fitted in period the rear light shown is a modern item and red external battery plug attached to the wing pylon support plate is also a recent addition that was not fitted in period.

Hunt’s M23 at Long Beach 1977:
http://www.f1passion.com/forum/viewtopic.php?t=14300

Third post, note:
• First National Bank advertising on the front wings,
• The higher windshield which appears not to be tinted,
• The all red cockpit surround (i.e. no white lip) and the black tape around the cockpit surround lip,
• The roll bar which appears not to be chromed,
• The bracing to the roll over bar which is an inverted “Y”,
• The additional brake cooling ducts at the top of the front uprights.

Another Long beach Image of Hunt’s M23 can be found here:
http://www.racingsportscars.com/f1/1977 ... 03-001.jpg
In addition to the above note:
• Shiny, polished metal front wheel rims (the M23 usually appeared with all black front and rear wheels)
• What appears to be a shiny bracket with two holes in it on the front roll over bar / instrument panel support.

An image of Jochen Mass in the M23 in 1977, location not known but either South Africa or Brands Hatch Race of Champions at a guess:
http://lh3.ggpht.com/-qCgqz1DMqQs/SbriB ... ous056.jpg

Note:
• Additional brake cooling ducts at the top of the front uprights,
• The location of the rear light partway up the rear wing pylon.

Regards,

Hacksaw

[generationx]

This is impressive work, a labour of love! Very useful stuff.

[ewestra]

Thanks a million Hacksaw. I saw that I've made a few mistakes. I'm lucky that I've not started spraying clear. I messed up the cowling and spend a lot of time to remove the paint. Soon be on track again and post some pictures.

Again thanks

Eric

[Nigel]

Add one more detail on the gear box. I linked up with Alistair Caldwell who was the #2 at McLaren at the time on Twitter. Found the link at Ron Howard's twitter as Caldwell is going to be on site during some of the filming as a consultant. That said, I asked about the 6 speed gear box and he mentioned that it used the same casing as the Hewland FG400, so no modification is needed.

[drledford93]

So, is the car as presented in the 1/12 kit accurate for any particular race? Or, do changes need to be made for *any* race?

[eyckles]

Hi hacksaw,

Thanks for all the information. Great research work that you are sharing here. Are there good pics available from the 1976 M23 with the high airbox?

Atb,
Lesley

[Hacksaw]

Mclaren M23 1976 The Details Part 2

Rear Body Extensions - Kickups
Contrary to what that know it all Hacksaw said in his first piece a year ago about the details of the M23 I have since found that the kickups on top of the rear side pods extension were used in the 1975 season although not on a regular basis and possibly only in the Austrian GP by Mass.
The worst image ever from the 1975 Austrian GP shows these:
http://www.racingsportscars.com/f1/1975 ... 17-002.jpg

Also of interest in this image is that the front wings and end plates are all red.

Mass also used the kick ups during the Swedish GP weekend although I am not sure about the race itself:


Under Body Skirts
By the mid 1970’s the introduction of deformable structures increased the width of monocoque tubs which in turn introduced the tug of under body ground effects and the first realization of what this was started to be appreciated by designers.

The M23 sprouted plastic strips attached on the bottom leading edge of the radiator cowlings; these strips were not vertical but angled forwards. The colour of these strips was initially clear but they soon became fogged and developed a yellow tint. At some stage in the season the line of the plastic strips on the bottom leading edge of the radiator intakes was extended under the car forming a “V” pointing towards the nose. The strips of plastic did not meet at the point of the “V” there was a small gap, while these skirts may have touched the road over bumps or under heavy breaking they were generally clear of the road by at least an inch if not two. Motor Sport reports indicate that these plastic strips were first tried during practice for the first Grand prix of 1976.

Links to images:
This cutaway drawing of the M23 shows under body skirts extending along the side of the side pods, but I have not been able to find an image of side skirts in use during the 1976 season:
http://forums.autosport.com/index.php?s ... read&st=40
(From the Atlas Nostalgia web site, “The Mclaren M23 and M26” thread second page, posts 65 and 79.)

Belgium GP: No skirts,
http://www.diariomotorsport.com.br/wp-c ... pany_3.jpg
Also note the line of the chine on the air box and particularly how this rises towards the rear,


British GP: Skirts in place on the lower leading edge of the side pod can be seen in this image, but there are no skirts on the outer edge of the side pod,
http://www.flickr.com/photos/27201648@N ... hotostream


M23 USA GP 1976 note that the under body skirt extends the length of the leading edge of the side pod but not along the side.
http://www.pbase.com/fjbertram/image/132648357


The front dust cover of the 1976 Autocourse annual has a low, head on picture of Hunt’s M23 showing the under body skirts almost meeting at the centreline of the car.
http://www.amazon.com/gp/product/images ... 55&s=books


Steering Rack Locating Bolts
The steering rack securing bolts are located just to the rear of the front suspension openings in the top of the monocoque tub. Close inspection of the car and photographs reveal that the two lines of three bolts as depicted in the 1/12 Tamiya kit are incorrect. The correct arrangement should be:
• Two bolts on the left-hand side,
• Two bolts separated by a smaller central locating pin on the right-hand side.
This link to a contemporary image refers:
http://galeria.wxatgp500.co.uk/MartiniL ... M23_02.jpg

Note that the bolts are secured with locking wire.


Front Wings
Jochen Mass raced with the leading edges of his car’s wings and on occasions the leading edge of the nose cone painted red. The front wings to the Hunt cars were all white, at some stage in the season a clear anti-chip tape was applied over the leading edge of the front wings and the nose, as the season progressed this tape developed a yellow tint, that can be seen of the front wings of Hunt’s car while the yellowing anti-chip tape applied to Mass’s cars resulted in the red leading edges turning a darker shade of red as the season drew to a close.


Rear Wing Pylon Support Plates
The two plates that were mounted either side of the gearbox to support the rear wing pylon changed over the course of the 1976 season. The trans-kits that I have seen represent the outline of the later season support plates but with fewer holes. The following links show these plates at different race meetings, note how thick the plates are:

Early season International Trophy at Silverstone:
http://www.flickr.com/photos/gillfoto/4991830687/
Note: Hunt’s open toed driving boots.

Monaco - note that the cut outs are circular not the earlier and later multisided shapes:
http://www.motorsportretro.com/wp-conte ... Monaco.jpg

A cutaway drawing of the M23 showing the later season rear wing support brackets (but with only two rows of adjustment holes not three)
http://imageshack.us/f/29/m23.jpg/
Note: I would not advise forum members for follow the representation of blue wheels and brake components shown in this cutaway drawing.

A 1975 wing support arrangement:
http://www.flickr.com/photos/alansart/5726656095/

A contemporary image of the late season M23 rear wing support brackets:
http://atspeedimages.com/showcase.php/0 ... 19e3f8e432

A contemporary image of 1977 rear wing support brackets:
http://www.flickr.com/photos/rabiit/4242843580/


Advertising
Cigarette advertising was banned at the 1976 German GP; the wording was removed from the M23 airbox and the cockpit sides the resulting space being left blank while the brand name on the rear wing was replaced with the advertiser’s logo as seen here:
http://www.racingsportscars.com/f1/1976 ... 01-012.jpg

The front wings seem to have been regarded as being $pace for $ale by the Mclaren Team with Capital Radio advertising appearing at the British GP, This image while not being that clear gives a reasonable idea of the positioning of the logo:
http://www.flickr.com/photos/cx500/3977 ... otostream/

The Canadian Flag appeared on Hunt’s car at Mosport I have not found any information as to whether Mass had a similar flag on his M23. A picture of this appeared in the 1976/77 edition of Autocourse in which has the copyright attributed to Hazleton Securities Ltd., the flag is located on the right hand front wing close to the leading edge and endplate. I had planned on attaching a close up of the wing with the flag on it in this post as I haven’t been able to find another image on the internet but the F1M website is resolutely refusing to let me do so if you do need the image PM me with your own e-mail address and I will forward the image to you.
(My thanks to Icon Modeler for helping with the copyright details on this.)

Although not very clear the images also shows the bottom front wishbone to be tubular not fabricated.

First National Bank logos appeared on the front wings at the USGP East GP at Long Beach in 1977 (but I am not sure about 1976)
http://www.f1passion.com/forum/viewtopi ... 00&start=0

The ICL logo was prominent on the front wings of Hunt’s car in the 1977 South African GP
http://picasaweb.google.com/lh/photo/QL ... hVGD0cNrNg


The Tall Airbox
This is not really in my area of interest but here are some links for those who are building a model of the M23 with the tall airbox.

This link shows Hunt and Mass in the South African GP:
http://www.pprune.org/jet-blast/318211- ... a-397.html
About half way down the page post 7932, note the relatively “standard” windshield compared to the next image,

http://www.pprune.org/jet-blast/318211- ... a-398.html
Post 7942 at the top of the page. Note how in this second image the windshield has been cut down at the front and replaced by a vertical, white deflector. (There are other Grand Prix images on the same thread.)

This link should take you to an image of the 1975 Fittipaldi car with a tall airbox:
http://www.classicandperformancecar.com ... ?id=496210
The first image is of the car in period the latter two are of a restored so beware for example the third image of the series shows the car with an early season tall airbox and mid to late season support brackets for the wing pylon.

And another of Fittipaldi at the 1975 ROC:
http://www.mikehaywardcollection.com/pr ... en-m23.htm
Click on the image to enlarge it.

Similarly this link should take you to an image (seventh from the bottom of the page) of Mass in 1975 sporting a tall airbox on his M23 at Montjuic Park:
http://voltarpida.blogspot.com/2009_11_01_archive.html

That is enough from me; if any one has any comments or can add to these notes please do share whatever information you have that may be of assistance to modellers on this forum.

Hacksaw