A paperboard Lotus E21

[PaulB]

Hi chaps,

a new episode of my never ending Lotus Project, namely finishing the underbody and Coanda exhaust.

What happened since the last post? Beside manufacturing the Coanda exhausts, where I used a colour spray lacquer (chrome) for the first time, I added loads and loads of small features to the floor. That means stuff like skid blocks, heat shields, IR cam housings, tyre vanes, diffuser strakes, diffuser gurney, live locks, some sponsor/partner labels, reinforcement stuff, bolts, skid planks or CFRP textures.

As I mentioned, I introduced some new techniques, namely the chrome spray lacquer for the Coanda exhaust groove for example. After it initially worked flawless, it happened that I run a bit into trouble when applying the final layer of clear lacquer. On the chrome can it says, it's not compatible with clear lacquer, but I thought, clear lacquer will just run off the chrome surface. Instead, it dissolved most of the chrome...

Another new technique was, to use a special glue for applying big-surfaced CFRP areas. Previously, if I bonded on the CFRP texture (90g/m² paper) with my usual glue, it happened that the paper started to dent. The new glue is much less aggressive and does not show this properties.

Enough blathered, here are some pics of 448 glued paper snippets:


That's the floor structure shortly before getting "carbon fibred". The white stuff you can see is mainly some reinforcement structure. I tried to rebuild the structures as true to the original as possible. Some of the white stuff at the front is also just a 3d radius.


That's my first try with coloured lacquer. To paint the Coanda exhaust grooves with chrome seemed to be a good idea. It looked great as you can see in the next picture. But unfortunately the chrome lacquer and the final clear lacquer aren't good friends...


The Coanda exhaust panel after painting. The chrome is pretty soft, so you can see my finger print at the end of the Coanda groove. I did a little bit of a hardness/dryness test.


The famous Lotus floor stay. Wonderful shape! Teams racked their brains to find out, why the Lotus stay was shaped like this. It stayed just for the 2013 season in this configuration.


The floor front corner with its weird shape. The strange bulge coming from the inside of the car houses the lower crash elements.


The blown starter hole air intake below the Coanda exhaust. Red Bull introduced this idea already in 2012. Lotus and Caterham followed in 2013.


The Coanda exhaust panel from the inside. Not very spectacular, but you can see the port for the exhaust manifold, the whole heat shielding and some live locks (i.e. kind of bolts) to fix the surrounding bodywork.


The tyre vanes which help to lead the exhaust plume towards the gap between the tyres and the floor. You can also see the IR sensor housing (outside of the main tyre vane) which looks at the rear tyre to log their temperature development.


The rear of the floor with the diffuser. Very good visible is the diffuser gurney which helps to prevent a stall on the diffuser underside. With the new restriction of the diffuser height mid of 2011, teams switched from the classic diffuser gurney to a slotted gurney which is more like a little wing at the top of the diffuser. Another tweak to handle the new diffuser height restriction of 125mm (it's actually not new any more in 2013/14), was to expand more in width. So, the diffuser rise starts with a width of just about 700mm and expands to the rear to the full 1000mm (or slightly below).


The diffuser viewed from the rear. That's a very good view to see why it's called "slotted gurney". It's not actually a gurney, but a little wing with a gap to the top surface of the diffuser. Often this wing is also provided with a little gurney itself.


The Underbody from below. You can see all the fixing bolts where the floor is fixed to the chassis and the engine. Notice the different wear of the three skid block pieces.


As already visible at the top picture, the Skid Block is splitted in three pieces (permitted by the regulations). This shows the front piece which is fitted to the T-Tray and is therefore the element which mostly slides on the track.


A good view on the important heat shields which prevent floor damage due to hot exhaust gases. The shedding edge you can see is the area, where the exhaust plume enters the floors underside. Also notice the different CFRP structures at the diffuser.


The car in current state. Still no end in sight, but slowly you can imagine whereabouts this project will lead...


That's it for now! Cheers,
Paul

[PaulB]

Interim Report:
Something about Rear Crash Structure, ERS Battery, Exhaust System and Rear Wing

Pretty long time went on since my last post. Some work on uni, some work in Formula Student and a move into a new flat prohibited me working a lot on the Lotus. Nevertheless there are some news since the last report.

Where should I start? Probably it's worth mentioning at the beginning that the gearbox is now finally fitted to the engine. This comes along with the finishing of the hydraulics pump/hydraulics system which sits on the right hand side of the engine beside/behind the oil pump.

After fitting the gearbox to the engine, I started working on the rear crash structure. Nothing very impressive or interessting to tell about it. With the fit of the rear crash to the gearbox, the car reached its full lenght of 507mm. It should actually be 508mm long, but one mm is within the acceptable tolerance (indeed it's less than 0.2% deviation). Of course the rear crash structure is hollow to allow the fit of a working rear light.

Another work which was done within the last two month is the production and fit of the ERS-battery. Although the battery isn't visible on the finished car, I produced a simple battery model, just as a "nice to have item".

Next point on my (still endless long) to-do-list was the manufacturing of the exhaust manifold. Always a very demanding and not really liked work. For the first time in my modelling career, I produced an exhaust system, lacquered with a chrome spray. And it looks convincing. The system is already fitted on the car. And the packaging is stunning. I had quite a few problems to make the underbody fit to the car with the mounted exhaust manifolds.

Subsequently I started working on the rear wing. End plates and flaps are finished, DRS and beam wing are still under construction.

There are also some bad news. I had to grind off the whole cooling ducts in the side pods as they were too wide at the bottom. Coming along with this, my radiators are also worthless and need to be redesigned. Luckily radiators are not very demanding to design and build.

The car currently has about 3100 parts. About expected 2500 more to come.

Finished rear crash structure.


Rear crash structure fitted to the gear box.


ERS battery installed to the car. The battery will disappear after fitting the underbody.


The raw and unpainted exhaust manifolds. Each pipe consists out of a steel wire as the core element wrapped with some layers of paper.


Painting process of the rh exhaust manifolds.


The finished rh side exhaust manifold.


The engine area from below with fitted exhaust manifolds.


Rh side exhaust manifold.


Lh side exhaust manifold. There is a heat shield clearly visible to protect the power steering hydraulic line.


The underbody is waiting for getting fitted to the car.


The lh side exhaust manifold with the fitted underbody. The packaging is extremely neat.


The RWEP internal structure. It's a bit more complex as it looks from the outside. Each endplate consists from almost 40 parts.


RWEP vanes.


The rear wing in its current state.


The destroyed cooling ducts...


At the end a nice video of the first try to fit the underbody to the chassis.
[youtube]http://www.youtube.com/watch?v=b3C0m1A9Jbw[/youtube]

That's it for now. Thanks for reading!

Cheers Paul

[knabbel]

This is nuts! What an incredible attention for detail!

[RicME85]

Excellent update as always Paul.

That video shows just how rigid the model is. Impressive!

[n04h f1]

Wow! The attention to detail is incredible.

[EAKMotorsports]

getting better and better at each new model, great job paul

[PaulB]

Thanks guys!

End of "creative break"
Finishing rear wing and start of of internal duct design. Furthermore - finishing my Bachelor degree.

As my Facebook followers might have noticed, I had something like a creative break on building my Lotus. Main reason for this is to find on uni. As I was finishing my BSc degree in Mechanical Engineering and starting my Master studies, there was a lot of stuff to execute. I guess, now in the summer month, there should be much more progress on the car than during the past few month.

Two days ago, I restarted working on my E21. The last few bits I did on the car was assembling, painting and fitting the rear wing to the car.

After removing the existing side pod cooling ducts due to non-compatible size of themselves (a design error), I started to design new one with all the given circumstances. The left cooling duct houses the water and gearbox-oil radiator, the left one engine-oil and ERS radiator. I'm still not completely sure, where the hydraulics cooler sits. Probably at the top of the monocoque below the airbox. As you will see in the pictures below, it's a tough challenge to achieve the extremely tight packaging, especially in the area around the exhaust system and the radiators.

The airbox is a bit more complex than the previous airboxes I've built so far, but the design process didn't showed any big problems.

Next things on the to-do list are finishing these ducts, than design and build all the electronics sitting in the side pods (ECU, PCU,...) and the PDRS ductings. Now let's take a look onto the car.

Assembled rear wing, DRS and central stay are missing. To keep in mind, the fully assembled rear wing consists of 120 parts - actually not a lot if you compare it with the 100+ parts of a steering wheel.


Car rear view with fitted rear wing. The wing is mounted via a stay on each endplate onto the top floor surface and a central support, connected to the rear crash structure. Notice the nice monkey wing, which will support the PDRS second pipe later on.


That's the rh rear wing end plate fixing point. These points are mainly to balance the wing. Most of the load goes thru the central stay which you can see on the next pic.


The rear wing central fixing point is mounted on the rear crash (which is naturally very stiff). With the ban of the beam wings in 2014 (which is a bit of a weird regulation change in my opinion), the central support is replaced by a big stay, connecting the top of the gearbox with the main rw flap (you can see this an all current cars).


The rear wing flaps with DRS. Also notice the slats in the RWEP. That was a tough challenge to get them reasonably good looking. The wing is a bit dusty - I should clean the car.


RWEP with its remarkable mini strakes.


Lh side cooling duct for the water and gearbox-oil radiator. You can see how challenging it is to achieve such a tight packaging. The exhaust system lies just above the radiators.


Lh side cooling duct for the engine-oil and ERS radiators. The ERS radiator will be mounted on the lower end of the duct where you can see the small slot.


The airbox with its jig.


Airbox fitted to the car.


Car top view


That's it for now!

Cheers

[PaulB]

Slowest progress ever...

Redesign of cooling ducts, finishing airbox, starting with electronics design and fitting process of the radiators.

There was a little progress over the summer since the last post. My intended finishing date for the car was something about in spring 2017, but with the current progress rate it could move into the summer. But one after the other:

1. I finished the redesign of the side pod cooling ducts. I did a design, when I built the monocoque back in autumn '13, but in spring this year they proved to have a wrong size and position to fit the radiators (collisions with floor and exhaust end pipe). So, after the redesign they look fine, but it's still a huge challenge to manage this tight packaging. I see more problems coming when designing the engine cover.
2. Quick note on the airbox: All done, lacquered, fitted and sealed. No problems at all.
3. A few weeks ago, I started with the electronics design. The electronics are fitted in the side pods each below the radiators, below the drivers seat and at the front of the monocoque. The rh side pod is already filled up with just missing out the cooling duct for one of the boxes. Btw - all electronics data are free available at mclarenelectronics.com - thanks MES for that!
4. At the mo, I'm fighting to get the radiators properly fitted to the ducts.

Lh side pod duct - this duct houses the water radiator and the gearbox oil radiator. The gills in the side pod top face helps to get the hot air away from the radiator.


RH side pod duct - this duct houses the engine oil and the ERS radiator. At the very front of the duct you can see another duct which taps off a bit of air to cool the electronics that are housed below the duct. The big duct at the end of the main duct is for the ERS radiator. This will be better visible in a picture below.


Here you can see the finished radiators. At the front - engine water and gearbox oil, at the back - engine oil.


LH side pod with fitted radiators. You can see very good, how close the exhaust manifold is positioned to the cooler.


RH side pod with fitted radiator. Still a collision of the drain pipe and the exhaust manifold...


Top view of the car with fitted radiators. Against this view looks like, the radiators do not overhang the floor (which exploits the maximum width of 140mm). With fitted engine cover, the width should be 138mm.


Airbox is waiting for getting lacquered...


Airbox is waiting again - this time for getting fitted to the car.


Nothing to wait any more for the airbox. Fitted to the car and sealed off.


The electronics in the RH side pod. Also the ERS radiator sitting behind the electronic boxes is well visible. I could start to explain which box is what, but that would be too much I guess. Also notice all the live locks to fit the engine cover. Zoom in for details...


Cheers, Paul

[PaulB]

Summary report of December, January, February

Design start of front and rear suspension, manufacturing rear suspension and barge boards.

In December I started designing the front and rear suspension. Designing the suspension is one process, to get the suspension properly onto the car is a different step... The design of the suspension is based on the chassis/gearbox mounting points and the wheel position. The manufacturing of the rear suspension is almost done, just the pullrod is missing. The positioning of the upright relative to the chassis is one of the most essential points in the building process as it defines the position of the car above the ground in finished stage. For this reason I did a jig to position the upright correctly and connect it via the suspension arms with the chassis.

Also the barge boards are already manufactured and are awaiting the lacquering process (as well as all the suspension elements).

Front suspension layout: castor 3.5°, negative anti dive, king-pin inclination 8.5°, camber ~4°, track 146mm, minimal toe in, car inclination >1°. Some of the values are just guessed or given by wheel and upright geometry.


Rear suspension layout: king-pin inclination 19°, camber <0.5°, track 142mm, minimal toe out, static drive shaft inclination ~7°.


Rear upright structures beside the drawing. This structure is built from 0.5mm cornflakes card and later covered by 0.3mm silver card. Stiffness of the uprights is the essential property.


The finished lh rear upright (25.3mm x 19.5mm x 5.7mm).


Rear top wishbone - note the different fibre directions and weave styles.


Rear bottom wishbone - also note the different weave styles. The safety rope to stop the tyre from firing away from the car in case of an accident is placed in the backward arm and covered by a carbon cover (that's the area with the different weave style).


All rear suspension parts (pullrod is missing) are waiting for getting lacquered.


The rear suspension in an early stage. At the top WB the structure can be seen, at the lower one, the metal wire can be seen which stiffens up the whole thing.


Rear suspension in a late state.


Jig to position the rear upright.


Barge boards.


That's it for now, thanks for watching!
Paul

[Rhodium]

amazing !

[PaulB]

Design start of cockpit internals, fitting radiators and finishing rear suspension components.

As uni stuff (exams) is coming to an end slowly, I've a bit more time left now and car progress will speed a bit up during the next time.

Over the last few weeks, I've done quite a lot of (more or less) small detail work on the car. First of all, I've found a suitable grid for protecting my radiators (metal grid with about 1mm mesh size). After fitting this to the rad ducts, I was finally able to fix the radiators to the car. A bit of detail work is still missing there, i.e. proper sealing, pipes, etc..

The next building site was the finishing of all the rear suspension components with clear lacquer. As I don't have a proper paint shop (room), I had to wait for acceptable outside temperatures for lacquering on our balcony.

Next point are the cockpit internals. As I have to wait a lot during finishing and mounting the rear suspension, I need a site where I can build at and not touching the car a lot. So seat is more ore less done (picture series below), steering wheel (picture series below) is well on the way and some small bits such as “dashboard” (that's the tiny bit at the drivers right hand side with fire extinguisher and ignition button on it) or belts are missing.

There's not too much stuff missing at the car now. Front suspension, brakes, wheels and engine cover. Nevertheless, I expect finishing the car not before middle of autumn - maybe October.

Rh rad duct with fitted grid. Same proceedure at the lh side pod.


Rh side pod viewed from the front. The cooling duct for the electronics is outside of the grid. You can see it a bit at the lower face of the duct directly in front of the grid.


Rh side pod with fitted radiator. It will be a challenge to get the cooling pipes packed beside the exhaust system. There I made a little mistake. If you can call it a mistake... The exhaust manifold should be tilted a bit more outside the car. In my case, it almost touches the chassis. So there is very less space for the backflow pipe of the oil (rh) as well as of the water (lh) radiator. But I'll find a proper solution to manage this little fail.


Rear suspesion stuff and barge boards finished (8 shiny lacquer coats for the barge boards, 5 mat for the suspension arms).


Here you can see my "seat shell tool" which I've designed entirely from 2d shapes. Beside, you can see the basic structural element of the seat shell in raw condition.


First, I layed up the basic structural element (which could be seen at the picture above), followed by two side and one central element.


Top view of the structural part of the seat in my seat tool.


Seat demoulded from its tool. At the sides it needs to be trimmed.


First fit of the raw seat shell.


Final fit of the raw seat shell with stiffening boudaries (red stripes).


Finished seat shell.


Back view of the finished seat shell.


Raw structural (base) element of the steering wheel - front view.


Raw structural (base) element of the steering wheel - back view.


Steering wheel base in the paint shop - or, as we have learned earlier, on the paint balcony.


Placing buttons on the steering wheel.


Comparison between the Lotus E21 and the Red Bull RB7 steering wheel. The Lotus one looks a bit more bulky as it has the display on the wheel and not on the chassis. The team appraoches differs in this regard. RB7 steering wheel has 73 part (as far as I remember), the Lotus one has 60 parts in its current stage (shift paddles and some details are missing).


Rh cockpit side: emercency sticker, E21 chassis badge and some lines - I don't like to describe all the lines (all electronics).


Lh cockpit side: FIA sticker, track sticker (guess, which one is it?) and again some lines (two hydraulics for brake and FRIC-S and some electronics).


Cockpit view


That's it, thanks for watching!
Cheers, Paul

[PaulB]

Brake fluid reservoirs, exhaust pipes, fire extinguisher, radiator pipes, beer and more...

I've made a nice progress over the last days. There's not a lot missing any more. The main sites are front suspension, brakes, brake ducts, wheels and engine cover.
When I come to the end of a car build, I usually create a to do list with all the stuff on which is left. On this list I rate all elements with
+ which means, it's an easy, quick and nice, simple to build element
~ which means, it's a pretty simple element, but takes it's time and is not that nice to manufacture
- which means, it takes a lot of time to build the element

Front suspension, cockpit padding and engine cover are the last three minus elements (maybe also the rims).

The components and assemblies, I produced during the last few days are stuff like exhaust end pipes (with their helmholtz resonater - more on that in picture caption below), fire extinguisher, brake bias lever, dashboard, roll sensor, brake fluid reservoirs, pitot tube and some electronic stuff at the front end of the chassis.
Beside all this, I created a rim instruction. So the rim design is already done. Unfortunately I lost the drive shafts during the summer... So light delay at the rear suspension build.
At the moment, the car is at about 4000 parts.

Front view of the steering wheel - it consists of 107 single parts and has a diameter of 27mm. For comparison, the RB7's wheel has 73 parts and the R18TDI's wheel (much bigger) has 109 parts.


Back view of the steering wheel with clutch and gear shift paddles. At the best sake, I can't remember any more, what the top lever is. It seems, I got a little rusty... With the ruler beside, you can actually imagine the size of all these tiny elements.


A view into the chassis with removed seat and steering wheel. At the bottom, you can see the fire extinguisher, right handed the fire extinguisher switch as well as the ignition switch are mounted. At the left hand side, the brake bias lever is mounted.


Just the seat straps are missing - but it's actually hard to find suitable straps with the right colours and fabric.


That are the raw exhaust pipes. They consist of a steel wire inside and a thick paper cover (many cylindrical layers). Before painting, the whole structure is covered with a thin layer of glue and sanded down to get a clean surface. The pipe which is sticked on the actual pipe is the helmholtz resonator. It simply provides a steady exhaust gas flow to get a nice blown floor. For an exact description of the effect, just google. It's basically pretty simple.


The right hand exhaust pipe during the painting process. The left and the right pipes are a little different due to the different space conditions in the side pods (oil radiator right handed, water radiator left handed). The paint jig (beer crate and a steel wire) is a bit unorthodox, but it's simple and it works.


The right hand exhaust pipe in the side pod. It's not fixed yet, as the lacquer is still curing. But somehow in this position it will be later on. The packaging of these cars was already quite tight, but not really comparable to the current generation of hybridcars.


The left hand side pod without its exhaust pipe. But the feeding lines for the water radiator are fitted.


Something is going on at the front of the chassis. It's fully packed with brake fluid reservoirs, some gauge instruments and some electronics. Clearly visible, the pitot tube (air speed) at the top and the roll sensor at the bottom.


That's the roll sensor, nicely shaped.


To get an imagination on the size of all these elements... Note also, there's a 1 € Cent coin (diameter 16.25mm) lying on the chassis.


To do list


Rim instruction - all these parts are needed to produce a rim.


That's it fo the moment, thanks for watching!

Cheers, Paul

[PaulB]

Hi all,

a little bit more progress on my E21. This post sumarizes the work I've done over the past two month. A lot of small stuff like fuel fillers or electronic boxes, but also massive projects like front-and rear suspension and exhaust system.

The completion of the car is optimistically aimed to early spring, maybe March. Unfortunately it is too cold now, to do the paint jobs on the balcony. So the flat is a bit smelly from time to time.

The to do list is pretty short now:
- Belts
- Cockpit padding
- Brake calipers and cooling ducts
- Wheels, wheel hubs, wheel nuts
- PDRS
- Internal aero
- Engine cover
- Rear light

Next to come are the brakes.
Exhaust system is done. The packaging is really thight and it will get interessting to wrap the engine cover around it.


Gearbox and clutch control unit un top of the gearbox housing. BTW. Lotus/Renualt is one of the very few teams, which is still not using a carbon gearcase.


Cockpit internals are also done.


Fuel filler - Top (red) one is the liquid valve, the bottom (red) one the venting.


Internal aero surface - this secures a clear and low drag tunnel for the cooling air.


Rear suspension


Front suspension - wishbone structure


Front suspension


Brake discs - each consisting from 19 parts


That's it! Cheers!

[PaulB]

Hey guys,

and again two and a half moth flew by since the last post. This time again some bits are fitted to the car and the to-do list gets shorter and shorter. The completion of the car comes closer and closer. An expected finish could be at earliest by the end of April.

Remaining to-do's:

- Finishing cockpit padding
- Finshing brake ducts
- Finishing rain light
- Finishing wheel hubs
- Wheel nuts
- Wheels
- PDRS
- Engine cover
- Internal aero

The first five bits on the list are a work of maybe two weeks. The car is looking more and more attractive from day to day. But to increase the suspens till the "roll" out (maybe better move out), there won't be any picture of the ful car any more. Just on details.

Brakes with first parts of the brake ducts. There were some thougts to make the brake ducts/covers demountable (and therefore detail out the whole brake duct stuff). But that may cause the wheels groggy when mounted...


Some stages of brake duct stuff.




Finally all cockpit electronics done. I am not sure at all, if this looks like the real car. But I incorporated all electronic stuff a F1 car has into the car. So there wasn't actually much left for the cockpit. So it looks maybe a bit empty. Anyhow, it does look not too bad.


Seat belts before and after mounting in the car.



Seat shell with mounted rescue belts.


Cockpit padding in its current stage.



Original drawing of the rain light. Thanks a lot to McLaren Electronic Systems to provide this data for free! Original link: http://www.mclaren.com/appliedtechnolog ... rainlight/


That's it for now again, thx for watching.

Cheers,
Paul

[PaulB]

Hi all,

Some news on my Lotus...

The brake ducts/drums are pretty complex shapes, but were fun to build. They are, even if they are 2013s, actually not less complicated than 2017 brake ducts. The packaging of the whole brake ventilation stuff is impressively thight (as almost everything is on this car - but not that extreme as the 2014 upwards car generation). The rear drums feature a row of little wings to generate downforce directly at the wheel. The front ducts only feature a few vanes.

The wheel hubs are relatively simple shapes, but each consisting of 16 parts. Front and rears are almost identical.

One of the most complicated things to design and manufacture is the cockpit padding. In real-life, it is filled with a foam. My one includes a structure inside and is covered by black paper. The difficulty here is, that the cockpit opening is not to 100 per cent exact (means also not 100 per cent symmetric). So I had to design the padding not to the exact original measurements but to the model's shape - finally it is slightly asymmetric, but it fits pretty well.

Probably the most complex part on the entire car is the engine cover. Same as the cockpit padding, its shape has to be designed to the already existing bodywork on the model. Surprisingly the first design was already pretty good. Just two prototypes had to be designed till the right shape was found.

Remaining to-do’s:

- Finishing rain light
- Wheel nuts
- Wheels
- PDRS
- Engine cover
- Internal aero

I don't like to place another completely wrong estimated date of completion - like I've done in the previous post.

Cheers, Paul