I found this article 2 days ago on internet And it has indeed some very nice scale drawings of the 1920 pattern RRAC in 1/24 scale I copied and enlarged them to 1/16 scale.
The Fine Scale 1920 Pattern RR AC plans are based on the prints in the old Bellona RR AC publication. They are good, being based on the existing Irish RR AC, the only issue is the the top of the turret. It shows a welded on eight sided plate that now mounts a top turret hatch. This an Irish only modification and possibly only on this one AC. It covers the large hole in the top of turret that was needed for the large ugly cupola that they added and then removed. Unless you are modeling this AC, the plate should not be on any other RR AC. A mistake that Roden made with their model.
George Bradford has a book out called AFV Plans, 1914 - 1938 Armored Fighting Vehicles ISBN 978-0-8117-0568-4 (stackpolebooks.com) which has plans for the 1914 pattern RRAC in 1/35 scale (x 218% for 1/16). PM me if you cannot locate this book.
I have almost finished scratching a 1/24 RRAC (1914) based on the Finescale article by Lopez and I used a broken Franklin Mint RR Silver Ghost as a base - be prepared for lots of rivets! I have a fair bit of reference if you get stuck
I have to admit that I have this particular book on my book shelf, but didn't realize it had the 1914 Pattern drawings was in it
But I found them ...on page 1 of all places.......
I seems that a Bandai 1/16 Rolls Royce Silver Ghost ballooncar is comming my way in the near future , so I might call on you for this "fair bit of reference "
While I also bought a 1/16th Bandai/Entex 1908 Rolls-Royce Silver Ghost "ballon car" as a basis for a 1914 Pattern Roll-Royce Armoured Car, I soon discovered that all of the Armoured cars used 1912 (Chassis #2100) and later chassis's. The model will require substantial rework of the chassis; a short list includes, torque tube drive shaft, replacing the 3/4 elliptical rear springs with cantilever leaf springs, 4 instead of 3 speed transmission, adding frame king posts, etc. etc.
I bought my Bandai "balloon car" over thirty years ago and it is still in its box partially assembled. In my defense, I have since built a lot of 1/87 modern armour, one 1/1 27ft off shore racing all carbon fiber trimaran and since 2000, 1/35th armor. The correct spoked dual rear wheels are a difficult problem to solve for this kit. Seen others that just wing it and put an armoured body on it. It looks like a Rolls-Royce Armoured car.
I don't know if you know ... but there are several techniques of scratchbuilding spoked wheels, using wire, nylon thread, or plastic rod depending on scale, inserted into pre-drilled rims and hubs (which could perhaps be derived from a plastic kit by cutting out the moulded spokes), after the rims and hubs have been fixed temporarily to a jig. Try Google searches for "Harry Woodman" and "spoked wheels".
Not easy though to do accurately - one needs to mark out a jig for drilling. But it's not impossible (not that I have tried). At such a large scale, too, one may need to decide whether the fixing nut at the end of the spoke has to be replicated for ideal effect. Rather someone else than me!
The wheels can cause a problem. I first thought to try to copy the wheels (The kit has not enough wheels for a RRAC) and put two together to get the back wheels but it seems it won't be that easy......
The project you linked to was mine. I found some better references since then, including some more photos of the Indian Rolls, so I'm redoing the body from scratch. On top of all the other things Nailcreek mentioned, it turns out the chassis for the Armoured car is 10 inches longer than the on the Balloon Car.
New to Landships forum. The thread on RRAC 1914 pattern intrigued me.
In 2003, David Fletcher the then librarian at The Tank Museum Bovington advised me of the existence of the RRAC in India. He also advised they have looked high and low and no original drawings of the 1914 pattern RRAC have ever come to light. This lead me to visit the worlds only known 1914 pattern RRAC in India on 2 different occasions in 2003 and 2005 and 'reverse engineer' the body.
The Indian 1914RRAC is in very sad unloved condition. It does have a carport to protect it somewhat from monsoon rains. It took me 5 1/2 hours by taxi from Bombay to get to the RRAC.
Every body panel is 8mm thick. There are some panels missing but not too many: around the engine. The dash board is gone. The MG mount is missing. Any metal of any value is missing such as brass and aluminium including the aluminium firewall.
There is no evidence such as floorboard holes to show seats were ever fitted. The edges of the steel show very rough cut, probably hand cut by oxy acetylene. By contrast, the 1920 pattern RRAC at Bovington is very nicely finished on the metal edges.
If anyone can explain how to attach photos, I will put photos of the Indian car and the project car on the forum. I have tried to attach photos using the tree icon but with no joy.