Bob-car; The fastest category of soap-boxes with 2 individuals sitting behind each other. Maximum weight of 320kg.
Features; Full shape memory steel chassis (No suspension allowed) - 4 wheel steering possibility - Complete datalogging of variable parameters - CFRP body - KFRP bottomplate - Custom designed brakesystem, wheels, .... almost everything - Active cooling on front brake rotors
(Pictures with a blue border can be expanded, use Quicktime or VLC player for the downloadable movies)
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16-08-2009
The first race after the European championship is always one where the different participants discuss their evaluations and ambitions for next year. This year wasn’t different and the place to be was near Beauraing; Servy. A small town I’ve never heard before, but they have nice track although there is one speed bump halfway.
Great weather, nice track and participants with ambition, sounds like a good combination for a day of thrilling sensations and fun although unscheduled delays in the timing where a bit annoying.
The race was quite coloured, starting with a first position after the first run. The track is quite sensational as we achieved around 100kph in a forest which long subsequent corners and an end braking zone generating smoking brake disks. At the second run we crashed the bob in the tire wall resulting in a broken front wheel rim and a bended rear upright. A too brutal steering and brake correction of the under steer resulted in a over steering rear hitting the tire wall. As the noon-brake gave time for quick repairs the bob’s suspension was fitted with spare parts and more or less re-aligned while the body was repaired using an engineered way of Duck-taping ;-)
The third run went well gaining back some confidence, which was the base for an astonishing fourth run in an attempt to regain that first position of the first run. We ended the race in first position with a 0,3sec advantage on the second couple. In the last months, the good cooperation and confidence between Karine and I is now really paying of and resulting in a series of good positions showing the potential of the bob and its crew.
Below I added two videos, one of the 1st,2nd&4th decent of the Sevry race, attached with it a small review on the tire wall hit.
The second video is in preparation of the race at Thiange on the 3th of October, where Olivier Germay made a track recognisance by motor bike.
Bob repair at home removing both the front and rear suspension on the right side.
24-07-2009
The european championship is on it's way at Uersfeld in Germany. A separate page can be found here.
8-7-2009
Last weekend a nice but although difficult decent was driven at the ‘Arbre’ track near Profondville in the Walloon region of the country. As this was the 4th race of the season nearing the European Championship AND as results restricted themselves to 2nd and 3th AND as the weather was quite unpredictable quite a lot of risks had to be taken from the first run on, and effectively this tactic worked well and resulted into the first win for the bobcar. It has to be mentioned that we were helped by the cancelling of the 2nd and 4th run timings, but in the end a distinctive difference of more than 1.5 seconds was differentiating the winner and the runner-up. A video the the 2nd (afterwards time-cancelled run) is given below in a youtube version or in the original version(68mb).
Next weekend, in preparation of the European championship we are going to test on the championship track near the Nurburgring. The day after, the (in my opinion) most enjoyable descent I’ve ever driven is on the program, organized by the TPP-federation at La Redoute which is a famous climb during the Liege-Bastogne-Liege race. Report on this weekend will follow soon.
1-06-2009
Last weekend a superb decent was driven at On. Full of breathtaking sensations and surprises this is one of the top-tracks in Belgium. Personally I was not really satisfied as the bobcar went really well, but the pilot-skills and courage were missing. This caused again a second place in the general ranking, 0.4 seconds of the scratch time. Enjoy both the videos of our own decent in the bobcar and the one of Benoit in a C4 soapbox (one person max 220kg) with a beautiful spin in the first serious corner.
Original quality movies; bob (44mb) & benoit (35mb)
30-5-2009
In preparation of the race this weekend at On near Marche-en-Famenne, the bobcar was disassembled partially for realignment and finding some rattling components. Meanwhile I started a new page for the new sister the bobcar will get. As the 2nd season with the bob is in progression, time has come to start realizing a new machine with further improvements and new techniques.
26-5-2009
A few different races have been driven last weeks, from which I added a video. The race at Zandvoort was a demo-run for the bobcar while Soapbox 1 and Soapbox 2 were sold to the organizer of the race.
The race at Neuville-en-Condroz was full of surprises as the 2nd video shows. The weather was really unpredictable resulting in taking many risks in the first runs to gather a good score, in order to cope with the risk of rain in later runs.
The race at Plombières near the 3-border point of Belgium, The Netherlands and Germany was a superb descent with a lot of variation. Every run some new elements appeared which you haven’t seen in previous runs, like small bumps and hidden asphalt property changes. I hope this race will be organized next year as it is truly a remarkable and spectacular descent.
Meanwhile, the bobcar has partially been disassembled in order to do a general inspection and re-alignment after the demanding race of Plombières. The check showed the failure of one rod end in the steering, a bended upright, 2 tires with flat surfaces on it, two treads of screws which are disintegrated due to vibration of lead-ballast and some other minor issues.
Original format videos; Neuville (wet) and Plombières
20-4-2009
Last Sunday a technical scrutinizing was held in La-Roche en Ardennes. Also some testing was allowed on the prospective 2010 European championship track. The soapbox gave a good feeling while driving, and although some minor adjustments will be required, the car looks ready for the new season.
Two video’s of the two testing descents driven.
27-03-2009
Some things changed on the bob-car have been mentioned earlier, the new bottom plate, increased break reliability.... In addition to this, a new nose top is in development replacing the window as it had no use. The new nose top should keep the air laminar for a longer time decreasing the aerodynamic drag. More info on this will follow in the coming weeks.
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END OF 2008 SEASON
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1-11-2008
As the winter is approaching rapidly, which will mean my absence for a while due to a internship, I have to prepare a maximum amount of things before the new season's start.
First of all, some spare components have been made. Those include,
- 2 new front V4 rims
- 4 new reinforced single slide pickup uprights
- a new CFRP & GFRP nose
- some new axis
- 2 new V2 brake pumps
- 10 new brake callipers
Reassembling started; having disassembled quite a lot, with directly installing some of the new spare parts. The next picture is of the alignment process, which took almost a complete day. Previous alignments where done on the brake disks (which are not that flat), and without weighing the axis ‘weight’. This weight adjustment is done by varying the axis ‘height’. Now everything should be within one mm/degree, while every wheel should bear a clearly defined weight (60/40%).
Both noses (original and new one) before applying the clear coat. / The new single slide pickup uprights.
The new improved brakepumps and the redesigned callipers. / Result vs origninal design.
In order to realise aerodynamic improvements, a new one-piece bottom plate was produced. This started with a mould made at the Industrial Design faculty based on large metal sheets on a wooden skeleton. On this mould a release agent was applied. Laying down two layers of glass fibres, local reinforcements and a layer of Kevlar together with a polyester matrix material will normally result in a new bottom plate.
11-10-2008
While disassembling the soapbox for its winter check-up and changing different components for performance increase, some surprising things appeared.
For example;
* I've been running a season while on some uprights the bolts of the disk brakes touched.
* The Kevlar of the bottom plate is not resistant to the sun's UV radiation, as the covered top part is more yellow than the un-covered bottom part.
* The Polyurethane seals used in the brake pumps have different properties depending on the store where you buy them. I've used 3 times PU seals provided by 2 different shops, and all 3 of them have different properties. 2 types are absorbing brake fluid and are swelling (which caused the brake pump failure at Mornimont, earlier reported), from which one is even changing colour. The third type is getting softer and softer due to the fluid. Strange, so I contacted one of the suppliers again, and they have made on special request 10 EPDM seals, some kind of new rubber, with the same dimensions as the Polyurethane ones. On the picture below, one can see the 2 types of swelling PU seals (bluish ones) and the black ones, which are the new EPDM seals.
Some general pictures of the disassembly process.
Probably continuing the disassembly process some other surprises will occur. The disassembly will be continued till the bare chassis in order to check the welds and eventual un-expected deformations.
28-8-2008
The previously reported Mornimont race, was witness of a lot of luck and drivemanship as shown in the next video. The promised video coming from team Tchoupet (thanks to them once again ;-).
(6mb, quicktime format if downloaded)
Together with this race, our fixed championship reporter Jean Paul Vicqeray wrote a nice passage in his race report published on the national speeddown website, concerning the incident and the bob’s new copilot (to which I hereby would like to bring my excuses for incident).
26-8-2008
The Mornimont race of last weekend caused some troubles as can be seen on the next series of photos with a 0.3sec. interval (thanks to team Tchoupet). A video will follow.
The front brake pump failed due to a scratch in the master cylinder. Although a good result was in sight, further racing was not an option on only one brake pump left. The failure of the front brakes caused the locking of the rear wheels in the second frame, causing the car to turn in a first uncontrolled spin, followed by a second spin which was corrected and the run could be continued which only two seconds lost in this decent.
11-8-2008
At an average speed of 74.5kph from standing start, the 'La Roche' race, part of the European cup, is the fastest race in Belgium. Attaining speeds above 100kph on a constantly curving road of mixed asphalts and concrete plates in-between a century old tree forest is quite impressive, even for well experienced drivers. And experienced drivers where available last weekend, form all over Europe coming to this mythical track in the Ardennes.
Gael and David drove in the bob car together and ended forth, which is a pretty good result. Playing with different setups and tire pressures due to the constantly changing weather, proved to be challenging and in the end satisfying as again a lot of experience has been acquired. A video of this descend is available here;
2-8-2008
In preparation for the "Coupe d'Europe" race at La Roche en Ardenne, a small race in the town of Tombeek near Overijse was driven. In order to increase testing possibilities, the launch speed was increased by accelerating the bob with a car. A small video;
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14-7-2008 / 25-7-2008
European championship page
14-7-2008
Progressing in the preparation of the european championship, a small test race was done at the town of Etickhove near Audenaerde. A small drive by video
Further photos and videos about the european championship will be posted on a special page.
7-7-2008
In full preparation of the European championship, some set-up tests were done. In total we drove around 20times a small downhill in order to get the 'suspension' right. Apart for a tire explosion, everything went good and preparation is now continued by participating in a small race on Friday and another test day on next Sunday. A video compilation of last tests....
30-6-2008
The repair of the crached nose was executed and an additional reserve nose was prepared. Painting of the components took a few days of work, but the result is satisfying.
22-6-2008
In order to improve our knowledge about the different composites used, some tests where done to generate useful data about the materials. The information distilled from this data will be used to redesign the lay-up of the fibers of the new set of composite rims which are considered. The target is to keep the same stiffness as the alloy wheels, but having a weight reduction around 25%. The first set of composite rims where 3-part rims, now a 1 piece all integrated functional part will be produced which will be hopefully more pressure resistant. The fracture toughness of the composites when hitting a border or obstacle will be the major topic of concern, and will be investigated afterwards.
A movie of some of these tests;
Movie (composite testing, 8Mb)
16-6-2008
Some video's of the Leffe race where procured by the Viquerai family
Another general video of the Leffe race;
9-6-2008
At the Leffe race (yes also known for the beer), a lot of things went wrong. At the first big corner of the first descent the rear wheels locked while braking and the bobcar started to slip and hit a small wall. The descent could be continued and arriving last hairpin; again the bobcar slipped away on the rear and hit some straw bales. It was a shocking baptism for first time co-pilot Peter. The nose was quickly fixed using tape and adjustments where done on the braking system. Also a front rotor disk was changed and an axis because both where deformed. The front rotor disk on the right stopped rotating with the wheel which was caused by the shearing off the bolts caused by an unknown reason. This is probably the cause for the missing of front brake power. The 2nd decent went much better, the bobcar felt comfortable and arriving at the hairpin again, the bobcar spun away, but this was due to too high cornering speed. The finish (just after the hairpin) was crossed rearward. After some more adjustments to the braking system, the third descent went good, and arriving at the hairpin now we slowed down that much in order to surely pass the corner. It passed, but the speed was far too slow now, although the time was comparable with the best competitors. This means that the bobcar has a lot of potential; it had just to be used by the pilot! 4th and last decent, ca passe ou sa casse.... arriving at the damned hairpin again, steering in.... again the rear slipped away and a good time was lost....(Movie of 4th decent, the background noise is saying a lot...). Quite frustrating. It is clear that the bobcar promises a lot of things but fine adjustments and driver experience will have to increase in order to achieve a first victory. Now the bobcar will completely be dismantled and prepared for the European championship. Repairs are required on; 2 rims, steeringcollum, nose, front bulkhead, pulling hook system, front rotors, front axis.....
Movie (of 4th decent, 8Mb takes a while for loading, thanks to team Tchoupet)
18-5-2008
Tom made a video of the decent in Neupré, it is in quicktime format. Next weeks succesive races will be held all over the country in preparation for the European championship in July. Reports and pictures will follow.
Movie (thanks to Tom)
1-5-2008
After a few weeks of hard work, the bobcar is almost finished. It drove its first track day last weekend @ the Neupré circuit, close to Liège. The day started quite disastrous with an oil leak in the braking system, and tire that exploded hurting the author's leg quite seriously.
After those small problems, the 4 descents where driven without major drawbacks while a lot of useful lessons where learned. The handling of the car is superb but the aerodynamic covering of the pilot must be improved as he is still taking to much wind and thus aerodynamic drag.
Tom was the co-pilot in service that day, and he made a video of the decent (which I will add later on). Clearly a lot training will be required in order to improve both passengers cooperation while decending.
Hereby I added some pictures of the car now 4 days after the race. The car was completely dismantled and assembled again in order to check of bolts which came loose and application of some minor improvements.
Next race is on 18 of May in On.
5-4-2008
The body parts where painted and striped, and while they where baking in the sun, the kevlar bottomplate was made and attached to the chassis.
27-3-2008
While final assembly is taking place, the body is painted and tweaking of some small parts is finished, the first real high speed tests have been tackled. Those are very promising as different setups for the 'suspension' (officially not allowed) where tested, and they give really remarkable changes in the handling of the car, which is off course what you want if you changes things. The first real tests for the co-pilot proved to be quite scary as loss of the box’s control by the pilot is mainly felt by the co-pilot as the car mostly breaks out on the rear first, which is a very strange feeling when your driving 80+km/h in a corner and hell’s braking loose. (will post some video's later on)
In order to get more information about the box’s handling, a performance meter was acquired, giving the opportunity to make full 3D maps of the tracks, and evaluating the cornering and braking actions undertaken. This will give then the opportunity to estimate if later breaking and cornering will result in a faster but still safe trajectory. The data logger will be a custom unique combination of INS (inertial navigational systems), a high performance GPS receiver and powerful data logging with 3D flexible graphics displays, which will be plotted in MATLAB afterwards. (Thanks to Lucas for the writing of the MATLAB program!)
5-3-2008
As I had some issues with the oxidation of the aluminium used for the brake callipers (7075 which is really vulneralbe to oxidation due to moisture), I asked someone at the Aerospace faculty to get them anodized. Some pictures about this;
Preparation by applying the Lead cathodes
The acid bassin, used in order to remove the oxidation layer
Cooking the parts in demineralized water to close the pores.
A remark made while testing the car was the fact that there was to much torsional strain. In order to cope with this problem I took the car to the PMB workschop in Delft, and made some additional strud-braces. First a small calculation was done with a FEM program in order to estimate there influence, and normally the torsional strain should be reduced with almost 60%
30-1-2008
As I was in Delft, I made some parts which could be usefull, some additional brake disks for the rear and the front, and two halves of a new carbon steering wheel which will be used to make a new wheel with incorporated electronics.
18-1-2008
As issues on the body are causing some delay on that part of the project, the chassis and most of the metal parts where painted and baked. The aluminum will go to the Aerospace faculty to get a anodizing treatment to prevent further deterioration due to corrosion which is mainly a problem on the parts (the brake calipers) I manufactured for 7075 aluminum.
I also started the assembly of some chassis components like the suspension and the steering. In order to align the suspension, the marble plate bought is very useful as alignment till 0.1mm is possible, which is of course required for such a project.
As can be seen on the pictures, I will try to keep some kind of data log of the different suspension setups, as I remarked last year, the chassis of the soapboxes suffer quite a lot, and sometimes a re-measurement should be done in order to check the actual value with the original marked on the chassis.
At the PMB workshop a the TU delft I took the liberty to manufacture also some new axis from 32CrNiMo8, as the axis used for the testing where of a metal of unknown origin. As one may know, Chrome Nickel Molybdenum , or Cronimo is one of the toughest steels available, but as the allowed axis diameter is only 10mm on the outer side bearing (this because I wanted to use ceramic bearings with the largest balls possible), it might be required to go above 1100Mpa, and this can be only afforded by Cronimo without further heat treatment. An alternative is the usage of Titanium, but the processing requires then special tooling which is not available for me at the moment.
24-12-2007
Although the reporting wasn't my priority, I worked quite hard last days on the soapbox's body. The nose and side panels are finished, and the rear 'diffuser' is baking in the primitive oven on Christmas eve now.
All parts where made using a rough mould made from Styrofoam, and then a 2-3cm thick layer of clay was applied, after this the finish was done applying inserts and 'pre-cuts'. Then a layer of Twaron (aramid) fibers was applied on the mould, which was covered with a 0-90 layer of carbon followed by a 45-45 layer of carbon. The side panels are completely made of glass fibers, because of there lower stiffness which can be an advantage in side impact accidents, and where reinforced with a 3mm layer of Sorex which will give the total part again some stiffness.
The 'oven' fed by a fhön can reach a steady temperature of 65°C
The carbon diffuser in the oven becoming the last major body part of the soapbox.
The nose and side panels mounted on the chassis. Also one can clearly see the rear seat installed, which was made previously.
9-12-2007
Quite productive weekend. Made the passengers seat with foam, using Nicolas as model, and afterwards put some 3cm of clay on top to make a smooth finish. Made a fibreglass mould of this, and used as the negative mould for the seat.
Then the soapbox was ready for it's first real test. Added a movie (passenger's view);
The test learned a lot of things, and immediately we also tested the new higher performance brake disks at the front;
27-11-2007
Added an more accurate fem-analysis and a small movie about the manufacutring of the rims.
Lathing movie of the rims (begin)
16-11-2007
Some pictures of the actual construction
Working on a marble table to ensure a fully straight and aligned chassis.
Different types of wheels; left an full aluminum one, on the right, a composite one.
Suspension; Everything on this picture (ex. rod ends) is manually self-made!!! ;-)
Sometimes beauty overwhelms rational thinking, the case for this carbon steering wheel
Some pictures of the destructive testing on pressure for the composite rims;
I was a bit disappointed about the result because the rim exploded at 7.5bar, which was at an almost 30% lower pressure than expected. The composite rim story will be followed later on as normally a very significant weight decrease should be possible to attain.
Rims (with sneak preview);
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Conceptual sketch (with thanks to Philip and Mona ;-)
