Human Power Team Delft & Amsterdam - Human Power Team Delft

Production details: Fastenings monocoque.

Today we will discuss one of the most important features of the VeloX3. The fasterners which ‘fastens’ all the separate components to the monocoque, which is the force-carrying structure and the exterior of the VeloX3.

Important requirements for these fastenings are precision, stiffness and strength. The positions should also be very precise, otherwise there is a big chance of misplacing the components. It is for example important to line up the front and back wheel very precisely to get the perfect driving-properties. At the same time, we have to prevent any deformations of these fasterners, since they can cause fatigue in the fixations. The fixations need to be placed on the inside of the monocoque. Lamination or simply gluing are widely used techniques to place them.
In our case, the VeloX3, we are using Mavom MA300 Plexus glue, this glue is based on 2 components and is 10 time stronger than a regular (fast-dry) epoxy based glue. Using this Plexus, some components will simply be glued to the monocoque. For example, the seat and back-wheel-suspension are fixed to the monocoque in this way.

Sometimes however, we will laminate some so-called ‘Big-Heads’, shown in the first image, on the monocoque first. By using these Big-Heads, we can easily connect the components to the monocoque. The Big-Heads are provided by TR-Fastening. Using some special tools we can precisely position the fastenings, using the precision by which the moulds are made.

Production details: The camerabubble

Now the testing with the VeloX3 has begun. From now on, the bicycle will mostly be optimized. This is also a nice time to elaborate on some interesting subjects from the production phase. Today, we are going to talk about the design of the camerabubble.

The design of the camerabubble turned out to be quite the challenge. The highest point of the monocoque of the VeloX2 lies approximately above the cyclist his head. However, as shown in the first picture below, the highest point of the VeloX3 is in front of the cyclist. To make sure the that the bubble does not disturb the air flow around the monocoque, the bubble is not placed on the highest point, but further to the back of the VeloX3.
To reduce the aerodynamic drag of the bubble to a minimum, it has the shape of an adjusted naca7 series airfoil. This form fits around the parts inside the bubble and minimize the drag. The total drag of the bubble is approximately 0.5% of the total aerodynamic drag of the VeloX3.
The camera bubble has to be able to see over the highest point of the monocoque. To make this happen as efficient as possible, the bubble is placed diagonally. This way, the connection with the monocoque can be placed behind the highest point while still delivering the best perspective (above the head of the cyclist). The stem of the bubble is quite long and thin and therefore vulnerable to vibrations. This effect can be reduced by selecting a stiff material.

The bubble was 3D-printed by our sponsor Mareco Prototyping. The bubble consists of two halves which will be connected after the cameras are placed. Inside the bubble, the connection of the two parts has to be made, two cameras have to fit inside of the bubble along with their cables. This makes the bubble quite a complex product which makes 3D-printing the ideal production methode!

Time to test our cyclists again

Last Tuesday, a Wingate test and a VO2 max test were done to measure the progress of our cyclists after a couple of months of training. Both tests were also part of the selection process last November. This makes it possible to compare the results of these tests with the results during the selection tests.

After handing out the new water bottles, probided by our sponsor BOOOM, it was time to start the Wingate test. This test makes it possible to measure the cyclist his average power and peaking power in only 30 seconds.
After a small break of about an hour, it was time for the VO2max test. With this test, the oxygen consumption of our cyclists while cycling can be measured. From the moment the test starts, 35 Watt was added to the resistance every minute. The entire test took 15 Minutes which makes this a pretty hard test to take.

The results of these tests will be used to verify it the training schedules have the desired effect. By analyzing these results it is possible to see what parts of the training schedules can be further optimized to prepare our cyclists the best we can. After a quick look at the results, it can seen that progress has been made and that we have to keep following this path. It is still four months until tha race in Battle Mountain, but it is getting there pretty fast.

Assembly: The VeloX3 is ready for testing!

In the last week, the last parts of the VeloX3 were installed. The first tests are already planned for the next weekend! In order for the VeloX3 to be drivable by the cyclist, it is important that it is controllable and that the driver can be cooled.

The handlebars are of comfortable length for the cyclist. Furthermore, the seating and the chain were mounted in the cyclist. There is enough space under the seat for the chain to go to the rear wheel.
Maybe as you know, the VeloX3 uses a camera system, just like its predecessor. This system contains a camera bubble on top of the bike, in which two cameras are located, and two monitors which are located in the monocoque. Pictures of this system are also shown at the bottom of this blog. The information of the cameras is sent to the monitors. By using a camera system, a front window is superfluous. Namely, putting a window in the monocoque can result in an edge, which can disturb the flow. This is not preferable, because it will increase the aerodynamic drag significantly. This problem is thus solved by using a camera system.
It is of utmost important that the cyclist is cooled when he is seated in the VeloX3. Otherwise, it would be very uncomfortable for the driver to ride this bike, which will of course result a decrease in the maximum velocity. De cyclist is air-cooled: The inlet is located in the nose of the shell and the air will be directed the upper body of the cyclist by means of a tube.

At this point the VeloX3 is complete and it is time to start the testing and to discover any points of improvement. Testing of the VeloX3 is very important to discover flaws or any points of improvement. It is crucial in creating the faster bike of the world. Next week, the test phase will start, thus the VeloX3 will hit the road for the first time. The bike is going to be optimized, which will result in an optimum working human power vehicle with a very high maximum velocity!

Assembly: The frame and the fork

Just like the VeloX2, the VeloX3 is not entirely without a frame. In front of the bicycle, a suspension is needed for the front wheel and the bottom bracket. To prevent this from hindering the legs of our cyclist, a small frame is used for this suspension.

The frame consists of two parts which are connected by a rigid bolted connection. This can be easily disconnected and one part of the frame can easily be taken out of the monocoque. The reason for doing this is to make it easy do maintenance on the front wheel without removing the seat of the cyclist.
The core of the frame consists of foam. Before the frame was laminated, the aluminium inserts for the bottom bracket and the headset were placed inside the foam. Thereafter, a layer of carbon, of approximately 1 millimeter, was placed using the hand lay-up method. During this process, the inserts for the connection with the monocoque and the inserts for the connection of the two frame parts were also laminated to the foam core.

The forces that are applied on the front wheel are conducted to the monocoque by the fork and the frame. The Q-factor of the VeloX3, the distance between the outsides of the cranks, is very small. This made it quite the challenge to design the fork of the bicycle. The maximum allowed width of the fork was less than 9cm. By designing a steel fork, it was possible meet this requirement without sacrificing rigidity.

The VeloX3 in the wind tunnel!

Finally, it was time to put our design to the test! For the first time, aerodynamics of the VeloX3 were tested in the wind tunnel at the faculty Aerospace Engineering. It is time to see if the new design matches our calculations!
The aerodynamics of the VeloX3 are a very important part of setting a world record. Approximately 75% of the resistance comes from the aerodynamics of the bicycle. It is important to know that the VeloX3 is not done yet. We are still working on the parts to control the aerodynamics inside the VeloX3 and the surface of the monocoque is not completely finished yet. The surface will soon be made even smoother and the sticker with the graphical design of the VeloX3 is missing.

Why are we testing in the wind tunnel? There are a couple of things we wanted to test. First of all, the canopy sealing this year will be different than other previous years. We use a very thin canopy and we use small but strong magnets to connect it to the monocoque. We tested if this new system performed as planned and we were not disappointed! When taped correctly, using milar aerotape, the airflow around the canopy was not disturbed at all!
The surface of the monocoque is not completely finished, but it is smooth enough to keep the airflow laminar. To keep the air resistance as low as possible, it is important for the airflow to be laminar for as long as possible. By using an infrared camera, it is possible to see if the airflow is laminar or turbulent and to see the boundary between. It turned out that the boundary between laminar and turbulent flow was exactly at the calculated position! This means that the design is indeed as good as calculated!
However, the resistance values were a little bit higher than expected. There are a couple explanations possible. First of all, the surface of the monocoque is not quite finished. It will be made even smoother with the help of our sponsor AkzoNobel and after that, a sticker will be placed by our sponsor Omnimark. Another explanation is about the internal aerodynamics of the VeloX3. The parts to control the airflow inside the bicycle are not done yet which means that we had no way of controlling it during this test.

Despite of the bicycle not being complete, it is safe to say that the VeloX3 easily passed its first real test! The air resistance values were already very close to the calculated values and the other tests were also a success! In about a month, The VeloX3 will be tested in the wind tunnel for the second time. Thanks to these results, we are confident to get even greater results the next time!

Assembly: The transmission

A lot has happened lately and things are going fast. A lot of small parts are being made and the assembly is going very well. At this moment a lot of different things are happening at the same time, but today we are going to talk about the transmission of the VeloX3.

In a previous blog, we already spoke about the transmission. The gears are being realized by using an ordinary chain drive, but this alone is not enough to realize the needed transmission ratio. That is why a planetary gear is used inside the hub of the rear wheel. Thanks to our sponsor Apex Dynamics, it is possible to realize the needed ratio in a small volume and with high efficiency.
The self-designed hub of the rear wheel was produced by our sponsor Doeko. The planetary gear system gets locked in the rear hub. This is the first version of the system. It turned out that the safety margins that were taken were a little bit overdone. The second version can be even more efficient!

It was also quite a challenge to make the transmission and rear wheel suspension. We cannot simply connect it to the monocoque, because we need to be able to do maintenance on the system. The choice was made to make a small part of the monocoque removable and connect the suspension to the monocoque.
Two big pieces of foam were glued to the inside of the monocoque and one layer of carbon fiber was laminated over it. Next, alignment blocks were used to position the wheel and transmission perfectly. The aluminium parts of the suspension, also produced by Doeko, were then glued to the foam blocks and two more layers of carbon fiber were laminated over it. This was all done using the hand lay-up method of laminating. This process and the results are shown in the pictures below. It is a result to be proud of!

3D picture

A couple of weeks ago, we traveled to XYZ-imaging in 's Hertogenbosch, were we made two 3D pictures of the first and second VeloX and this year's cyclists. XYZ-imaging is the only company in the world that is capable of making 3D pictures of objects with dimensions up to 6 meters, like our cyclists and the VeloX! The pictures have arrived and it is safe to say that the results are amazing and very imperessive! Behold the first and second VeloX and our cyclists from all possible angles by clicking here! Naturaly, we would like to thank XYZ-imaging for this unique opportunity and for the amazing results!

Click on the image to get a 360 view!

First time training

Last weekend it was finally time, the first testing day for our team at the Soesterberg air force base. A pretty exciting day, where we practiced the taking off and retrieving of the VeloX. Of course we had the help of team members from previous years. But it was still pretty exciting to do this for the first time.

After dividing the tasks between the team members, we finished all the check lists to prepare the VeloX. Chantal and Kitso, two members from the first team, were there to help us learn all the ins and outs of taking of and retrieving. The first couple of attempts were not flawless, but as the day continued we really got the hang of it. Our cyclist were also getting used to working with a new team. 

Battle Mountain Monitor Test

Slowly Battle Mountain approaches. The first shiny parts are being produced and the cyclists are training hard. In Battle Mountain, Wil and Sebastiaan will have to be in top shape. Meanwhile the foundation has been laid for a couple of tough training months. With only half a year to go until the race, it is interesting to see how things are shaping up.

For this purpose, we developed a test: The Battle Mountain Monitor Test. The goal is to find how the training is working out. It means that this test stays the same for the rest of the year. So if the cyclist finds the test less enduring, they progress in their training!
To get insight in this progression, a number of parameters are measured. These are respiratory analysis, heartbeat measurements, lactate tests, efficiency and recovery analysis. By comparing these parameters, we have a good reference between multiple tests.

Before the cyclists will be tested, the VU members will take the test first. This not only fun, but also very important because this is a newly developed test. This way the equipment can be checked and everybody will learn how to work with this test.
We are very curious about the results of this test and of course we will keep you up to date