Lotus E21 construction report part 3

Manufacturing start of the monocoque

As you may have recognized, there wasn’t a lot of action on my models the last days. Reason for that was, that my laptop was down and I had no material to work. Now these problems are conquered.

The basic upper shape of the monocoque is finished, now I just have to add a few inserts such as for wishbone or damper mounting points. I am thinking about doing a real inspection door as it is like at the real car at the top of the monocoque to reveal all the inside front suspension stuff as well as the pedals. Next steps will be to design the lower half of the monocoque with the keel and the cockpit floor as well as the fuel cell housing.

As usual I use the technical reguilation stuff for dimensioning the chassis:

In the course of this building process I will refer again and again to this two documents.


The basic part of the monocoque – the first ever part of every car. If you are a bit creative, you can imagine how I bend this part and identify the monoqoues shape.


Here you can see the basic shape with a few jigs to ensure that the chassis is within the regulations. Ref. 2013 FORMULA 1 TECHNICAL REGULATIONS-Drawing 5


A few items to glue into the monocoque.


Front bulkhead and front rocker bearing carrier. At the front bulkhead you can see the two big holes to adjust the front torsion bar springs. I assume to change the spring rate, they simply change the torsion bar. Also the four pick up points for the nose cone are visible.


The basic shape of the cockpit rear end bulkhead (seperating wall between cockpit and fuel cell). I actually don’t know if I just use it as a jig to bond the bulkhead into the chassis or if I use it as an integral structural part in the monocoque (bond it in).


Cockpit entry template structural inserts left and right. The sheet between them is the jig to control the shape of the cockpit entry.


Front bulkhead and rocker bearing carrier bonded in. At the cockpit entry template you can also see the inserts.


Cockpit entry template. The inserts at the side have the function to reinforce this area of the chassis as it is naturally the weakest point at the monocoque as it represents a open profile and as we know, a open profile hasn’t got a high torsional section modulus. I also used two different types of cardboard there: The outer shell of this inserts ifs from a card (some biscuits boxes 🙂 ) and the core is a card with a bit a less density just to reach the needed thickness.


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About paulsf1

My name is Paul Bischof. I’m a student in mechanical engineering at the Technical University of Graz in Austria, expected finishing in February 2016. Since I was eight years old, I am building model planes out of paperboard. Since 2004 I scratch (that means building without an assembling set) Formula 1 and sportscars in 1:10th scale. The average time I need for such a car is around 400 to 700 hours within 4 to 8 months. One car has around 3500 up to 5000 single components. On this blog, you can take a look on my work and later, after my studies, hopefully you can see me in Formula 1.

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