bottpower

Last weekend I continued drawing components from the Kawasaki ZX6. In this case the water pump, the injection body and the airbox.

Of course we must design a new airbox, but I thought it was interesting to draw the ZX6 one in order to have a reference. Regarding this airbox, it catches my attention that the box has a quite small size, and the intake conduit a big cross section.

To design an airbox is not a simple issue. Pressure waves produced by the intake valves travel through it, and it is necessary to dimmension the box volume and the intake conduit (length and cross section) in such a way that the frequency of the pressure waves going through the airbox matches the opening frequency of the intake valves at certain rpm (normally top power rpm).
Also it is necessary to achieve a design that maximizes pressurization at high speed, in this way it is interesting that the air intake is located at a high pressure area in the bodywork, ideally in the nose like for example the KTM 250 GP or de Ducati MotoGP.

It is also necessary to try to achieve an air flow as much laminar as possible inside the intake conduit. Theorically the cross section of this conduit should increase as it arrives to the box, in order to reduce the air speed and increase it’s pressure.

I would like to find a collaborator with experience in CFD (Computer Fluid Dynamics) to study these questions, and analyze several virtual solutions before deciding the final design. So if you know about CFD and want to collaborate in this project, please send me an email..  :)

Continuing with the airbox design, other points to take into consideration are the box stiffness, that must be stiff enough to avoid beeing deformed by the pressure waves. Also it is important to make the box and it’s cover watertight, in order to avoid pressure losses.
There are also other issues that add extra complexity, for example the airbox must house the secondary injectors. In the ZX6 airbox they are located on the box cover.
Finally, the intake conduit design determines heavily the chassis design, but this is a subject for another post.
Like always you will find higher resolution images in the Flickr gallery.

I had some time without writing about the Morlaco, a project that is going ahead at idle speed. Yesterday I took this photo that shows the current status of the bike.

Comparing with the last time I took photos, this is the new stuff:

• The bike has custom built Technoflex shocks.

• Carbon fiber airbox.

• Carbon fiber fueltank (here and here you can see 2 post talking about the fuel tank construction).

• The “triple clamp” is a new, stiffer one.

• I changed the steering rod-ends.

 Although currently I am fully focused on the Moto2 project, I want to continue working on the Morlaco, even if it is at idle speed.  

You can see a higher resolution photo in the Flickr gallery.

(Thank you Hugo for the photo postprocess).  

Tags: morlaco, prototype, construction

These days I am spending some time drawing in 3D all the standard components that will be used in the Moto2. With standard I mean all those components already existing and well defined (engine, brakes, suspensions, rims, tyres,etc). Once I had all these parts drawn and located in it’s position, I will be ready to start working on those parts that I must design and build (chassis, subframe, airbox, fueltank, bodywork, etc).

The first component I have drawn is the engine, a Kawasaki ZX6 2009 one. One of the design goals is to achieve a very compact bike, with an ergonomy as similar as possible to a 250 GP bike, so it is advisable to draw the components in a very precise and detailed way, in this way it will be easier to make the most of the avaiable room.

At the time to draw the engine, I thought about using a scanner. Nowadays there are very cheap scanners, like Nextengine which costs around $3000. This Handyscan is not so cheap, but it is impressive to watch how it works.

The problem is that with a scanner you get a points cloud, that it is necessary to convert to a “solid”, which is the kind of format I need to work with CAD. The process of converting the points cloud to a solid takes quite some working time. There are softwares which make this task in an automatic way (I never tested one, and I don’t know how well they work), but they are expensive. I also asked companies which offer scanning service, but the cost was quite high. So finally I drew the engine following the “classic” method, meassuring with a caliper, squares, straight edges, etc.

Chassis mounting points are meassured with a 3D meassuring machine, so they are located with a precission of hundredths of milimeter.

I think that the rest of the engine has been drawn with 1 mm tolerance, more or less. Regarding time, it took 2 days of work (a whole weekend). Maybe I could draw it less detailed, but I think I wouldn’t save too much time anyway. 

Tags: moto2, engine, CAD, 3D, scanner