With the underbody, I’m working now on (one of) the most important aerodynamic feature(s) of my Lotus. The underbody produces about 30% of the cars (negative) lift, but just a little fraction of its drag. The side of the floor is sealed by vortices, created by the barge boards at the leading edge of the floor.
Special features on the Lotus floor are the Coanda-exhaust sealed diffuser and the blown starter hole.
The Coanda exhaust, was the difference making aero feature in the seasons 2012 and 2013. The Coanda-effect describes the phenomenon of a fluid-flow, following a convex surface instead of separation of it and move along its original flow direction. In Formula 1, this effect was used, to lead the high-energy exhaust plume between the rear tyres and the floor to seal the diffuser. Some teams were able to control this tweak better than others. At the end of the 2013 season, Williams was faster by removing its Coanda system. The most effective systems were built probably by Red Bull and Lotus.
The blown starter hole is an aero tweak, to prevent flow separation at the middle area of the diffuser. There you take “good” air from the side of the car and lead it to the diffuser and exit it via the starter hole to re-energize the boundary layer. With the ban of the classic starter holes in 2014, some teams use vortex-generators to convert the air to a turbulent flow for preventing a stall.
Gearbox and Underbody Manufacturing
After finishing the Renault RS27-2013 engine, I started to design the gearbox (my usual process chain: monocoque-engine-gearbox-underbody-systems-suspension-wings-bodywork-wheels). The Lotus’ gearbox is a bit of a pain to do as they are one of the last teams, not to use a Carbon composite housing. It’s a cast Titanium structure. Williams is the second team in the grid not using a Carbon gearbox (Aluminium). To rebuild metal structures from paper is always very difficult. Anyway, it’s (almost) done and I can be pretty satisfied with it.
The whole suspension stuff is located within the gearbox. That’s a trend which appeared about three years ago. Before, most of the suspension stuff (dampers, springs) was mounted outside the housing beside the gear cluster. With the aero development over the last years, the teams started to locate all this stuff inside the housing in front of the gears, to get a tighter ass. I don’t know, if I’ll add all this stuff inside the gearbox. I will do the ARB and the drive shaft definitely but I won’t do the gears.
This week I also started with the underbody design.
Over the last few weeks I, was working on the RS27 Renault engine. In the meantime it’s all done except the fitting bolts to the chassis. The engine has something around 700 parts in its final stage.
The engine is much more detailed then the one at the RB7. As you might know, the Lotus E21 and the Red Bull RB7 have the same engines with just a few minor visible improvements. At the RB7 I haven’t built a throttle hydraulic unit or the injection system was much more trivial. Also the engine block as well as the pick-up points for the monocoque and the gearbox should be a bit more stiff and rigid. All in all, an expected overall improvement of the engine.
News on the Engine Manufacturing
This is more a tiny update just to keep the blog rollin. There will be more progress on the car when I’m back to uni finishing my mechanical engineering degree at the beginning of October. So look forward to that time!
As the engine is a fully stressed member of the car it’s very important to get a stiff and reliable connection between the engine and the monocoque as well as the gearbox. These connections I achieve with steel pins of 1.2mm diameter. On the real cars, the regulations dictates six M12 bolts to fix the engine to the monocoque as well as to the gearbox. Regulations around the engine cover bore, distance between cylinder axes, crankshaft height, bank angle, CoG, etc. With a bit of understanding of some engineering subjects and this data, it’s not that difficult to redesigned this engine from paper. It’s actually a bit like reverse engineering.
A bit belated, but finally this great video, which resulted from the great work of Video Director David Betteridge in cooperation with Siemens and Red Bull Racing, shows my rise from a simple model builder to a proper Formula 1 car designer.
I just want to say a huge thank you to all the people who supported me on my way into Formula 1. Enjoy!
Front Wing Design and Manufacturing
A long time passed by since my last blog. Lot of work at the factory, some holiday and other stuff went on. Last week I restarted the work on my Lotus. So, building the Front Wing was great fun as usual and if you compare the result with the RB7 FW two years ago, you can see a huge step in detail work, in manufacturing quality and also in some minor engineering skills.
In general I’m very satisfied with the result of the FW. The surface quality could be a bit better in some places. But that’s more a problem with restricted access as it’s like under the small Front Flaps. The FW-Nose Assembly is with 49g pretty heavy. That’s about 8.5% of the car weight. As you can see on a picture below, the stiffness of the wing is incredible. I did a simple deflection test where the wing resisted over 500g load which would be equivalent to 500kg(!) at the real car. I didn’t measured any deflection of the wing, but the regs are telling you, that the wing should not deflect more than 10mm at a load of 100kgs. Maybe I do a proper deflection test on a rig somewhen. Just for fun (This statement is a bit sensless considering this is my hobby and should be fun all time).
Anyway, except a few dimension overrides conflicting with the front bodywork regulations, I’m pretty pleased with my new Front Wing. I hope the guys from Lotus are too.
Engine Manufacturing and Nosecone
Over the last few weeks I was working a bit on the engine and finished off the nosecone. Of course, all beside RB10 troubleshooting.
The nosecone was actually not planned to build that early, but some circumstances forced me to build the nosecone now. This circumstances are some kind of a “secret project” which I’ll show you in a few weeks. Target date is first week of April. Wait and see…
Engine: Front wall of the engine block is almost finished. Mounting points to the chassis are all done and looking very stiff. Not much to tell about the engine any more. Apart from the to expect ultra high grade of detail.
The nose is also a huge improvement compared to the RB7 one. The laminate thickness is much more realistic (not that fat as it is at my RB7). However, the nose is very stiff and the nosepins are very rigid. The front wing pylons were also a bit of a weak spot at the RB7. On this nose, I reinforced the pylons with a steel wire each side and provided another tube for picking up the FW mountings. The shape of this nose was highly complex. Especially the bulge under the nosetip and the step were very difficult to get properly done. But everything worked out quite well without any big problems. The nose is probably a bit lower than the original, but at least it’s within the regulations.