Stuttgart - Day 1

We arrived safely in Stuttgart with an undamaged airplane. The youth hostel is very nice. Thursdaynight we went to the city center, there was a nice event going on, the Stuttgarter Sommerfest. It seems the hottest day in Germany since ever, 37 degrees.

The planning was very strict; we had to get up at 6u30 this morning for the presentations and technical inspections.

We saw some very interesting models, including the Chinese box wing and the Municher biplane with double flaps.

After seeing the presentations, it was clear that we were the underdog. But nothing is proven yet. We know our model flies :) Most other teams were much bigger and started to work two years ago. Some of them were very professional and were supported by their professor.
Our plane passed the technical inspections, so now we are ready for the first official flight.

This is our official proof of flight which we showed at the presentation. The model is rather difficult to control, but it flew after all. Tomorrow we'll start with a modest payload of 1,5 kg, but we plan to increase the weight later on.

Stay tuned!

Rudder and Elevator

We've finished the tail! Check out the video above! Last thing left to do: finish the outer parts of the wings.

Getting Ready To Fly

Hello everybody!

After a little break, we're now getting ready to fly our airplane. As the challenge is already in a few weeks, it's time to get serious. The electronics had to be connected to the batteries and the receiver had to be binded to de transmitter. The latter was fairly easy: we just had to follow the instructions in the transmitter manual. But to connect everything, we needed to make extensions for the servo wirings.

None of us had soldered before, so that was already challenging for us. But as it turns out, it was not that hard. Everything seems to work: our airplane can already "drive" on campus.

Check out the video below!

The result!

Here it is! Our aircraft in front of the department of Mechanical Engineering, completely assembled. Today was our presentation for the university, so we put the aircraft completely together. All it has to do now is fly the way we want it to.

Next up: the exams! We will return to you at the end of June :)

Final report

The deadline for the final report is here! The 4 copies have been sent out yesterday. Don't they look pretty? :)

Another visit to Dejond

Last Monday we paid another visit to Dejond, to place the Tubtaras in the fuselage. They placed 11 Tubtaras in total. These specific Tubtaras are also the ones Airbus uses in their aircraft designs.

Yesterday at the KU Leuven fair for first year bachelor students at the Engineering faculty, we showed off our aircraft. Hopefully some of these students are up to the task of participating in the future editions of the Air Cargo Challenge!

Landing Gear, Fuselage and Flaps

Things are finally falling into place. In the above picture you can see the total length of the fuselage. On the left side the motor and propeller are attached to the fuselage by a piece, 3D printed in FabLab.

The Tubtaras will be used to attach the fuselage to the landing gear. Next week we're paying a visit to Dejond again to help us. The picture above shows the placing of the Tubtaras on the fuselage.

We are still working on our final wings, but that doesn't keep us from playing around with the styrofoam wings we cut out at the very beginning of our project. Last week we tried to cut out flaps, so when we have to do it for real on the real wings, it won't be the first time we have to do it!

It still needs some tweaking, but this is what the lading gear will look like more or less. Of course the carbon tube of the back wheels needs to be adjusted, but it can drive already, hooray!

Bits and Pieces

During the Easter holidays, we had some pieces shaped with a lathe in the workshop at the mechanical engineering department, other pieces were 3D printed in FabLab and then there was one piece we lasered with the same laser cutter we used before for the cargo bay.

This week we assembled some small components of the aircraft, like the wheels for the landing gear. We drilled a hole in the middle parts of the wheels -which were also 3D printed at FabLab- to put the bearings in.

Next we put together the propeller and the spinner and then put it on our AXI Gold motor.

Finally we made a piece to link the front wheel of the landing gear to the cargo bay. As you can see in the first picture, this was the result of the immense man power of the boys in our team :)

Tubtara

Yesterday we paid a visit to our main sponsor, Dejond in Wilrijk. Besides providing us with a nice cup of coffee, they helped us out with some problems we had with connections between the fuselage and the cargo bay. We will be using Tubtaras, which are manufactured in Wilrijk and that are EN9100 certified for aerospace applications. They exist in different shapes and sizes, as can be seen on the picture below. 

Our toys have arrived!

Our orders are arriving in Heverlee! The photos show the package of electronics (batteries, servos, ...). Now that our calculations are almost finished, all we have to do is wait for all the orders to arrive. Sadly enough the foam cutter in FabLab was out of order, but as soon as it's fixed, we can start building our airplane and do a test flight! 

Comparing Airfoils

There were still 2 airfoils we were considering for our wings. Last Friday we cut out both of them to check which one would be easier to produce. It is clear from the picture above that de trailing edge of the right airfoil is a lot better than the left one. Because the trailing edge is really important to generate enough lift, we have selected the right airfoil.

A First Attempt at the Cargo Bay

Last week FabLab was closed, but this week everything was up and running again. After several weeks of cutting foam, we finally decided to cut something else. It's time for a first attempt at the cargo bay! In our design, the cargo bay is cut out of multiplex, but for our first try, we used a lower budget material: MDF wood. FabLab has several laser cutters at our disposal, like the one in the picture above.

The design of our cargo bay hasn't changed much in comparison to the one team KU Leuven used for the Air Cargo Challenge two years back. We've only made it a bit smaller. All the pieces of the cargo bay are cut out of one wooden sheet.

Afterwards the pieces are glued together with super glue. The result can be seen below!

SolidEdge Model

 

Last week, FabLab was closed. So instead of trying out some fun things, we spent the whole week behind our computers, playing around in MatLab and SolidEdge. I strongly doubt a picture of our MatLab code would be interesting. However, the 3D model in Solid Edge looks nice! A lot of things will probably still change, but this is what we have in mind at the moment. This week FabLab is open again, so we can start building stuff again, hooray! We hope to do an attempt at the cargo bay.

Something else we hope to do this week, is place orders for all the materials we will need during production. We have finally found the right sponsors for our project. Take a look here to know who is supporting us!

Tapered and Twisted Wings

This week, we cut out another part of the wing in FabLab. This time, we tried to cut out the right part of our wing. This part is tapered and twisted. In the video above, you can see that we used two separate styrofoam sheets on top of each other. We tested this because eventually we want to make our wings hollow to save some weight. Afterwards we want to glue the upper and lower parts back together. As you can see in the video, Cedric had to press the two styrofoam sheets together a bit, because there was too much space between them.

We also tried to cut out the exact same part of the wing out of one styrofoam sheet. However, our styrofoam sheets were not big enough. Therefore the upper part of the wing was not cut out properly.

Our first full scale wing

First of all, we had to program the foam cutter to get the desired profile. Our wing will consist of three parts that we can connect and disconnect. This time, the middle part of our wing was cut out in full scale. We also tried to cut out the holes for the carbon tubes.

Just like last week, we still have problems with the trailing edge. Of course the material we used for this first try is not of the best quality. We still secretly hope the problem will disappear when we use the right material. 

This is the result! Even though the wing material we used was just cheap styrofoam, we are still excited everything worked.

As you can see here, the trailing edge is not really good. The hole for the carbon tubes looks good. We're thinking about adding more holes in the wing, not to put more carbon tubes in it, but just to save some weight. That's what we'll try to do next time!

Playing with the new foam cutter in FabLab

After having determined our airfoil profile, the real fun can finally start: cutting airfoils out of foam!

First step: import airfoil data in DevFoam. Not even remotely difficult, but we are still super excited our design will soon no longer be something on paper.

Next step: cutting an airfoil out of foam on the foam cutter in FabLab. Rumour has it our department bought this foam cutter with the Air Cargo Challenge in mind. We're the first KU Leuven team that uses it.

Result: a miniature airfoil! We still had some problems cutting the trailing edge. The hot wire of the foam cutter melts away too much material. It's possible this will no longer be a problem when we cut our full scale airfoil. If the problem still occurs, we might have to look into other airfoils that have a less complex trailing edge, but still more or less the same lift over drag properties.

Next up: cutting a full scale airfoil!

The main aspects of our airplane design are nearly finished!
Next week we will order materials to start building as soon as possible.