I got an idea how to achieve suction to the read of the engine pod.
* The prop is located just after the laminar-turbulent transition to the pod and the remainings of the pod is a very large spinner which is open from the center.
* The air tunnel inside the pod has venturi-shape.
* There are tunnels that connect the venturi tube and the ring that is supposed to have suction.
* Airflow (which is used to engine cooling) inside the venturi (helped with the propeller part that is inside the pod) causes suction to the rear of the pod. The air exits at the end of the venturi tube, which happens to be the center of the spinner.
* The exhaust in the center makes the cut aft end of the spinner to still maintain low drag, it functions in the same way as the rear cut fuselages in jets

I have not tested this idea and don't know it it would work, but I think it would be pretty easy to try out in the model scale, even with an electric motor. This interests me enough that I think I am going to try it out of someone doesn't tell me (with better knowledge, as a fact that has been proven and tested) that it is not gonna work.

I hereby license this invention under the terms and conditions of GNU General Public License, version 3, or any later version. (C) 2008 Karoliina Salminen. All rights reserved. By reading this text, you aknowledge this and agree with the terms and conditions of the GPL license.

The winter season at Belgrade’s Nikola Tesla Airport in Serbia begins on Sunday October 26, 2008 and will last 5 months until March 28, 2009. The airport is expecting a growth of 10% in air traffic when compared to last year, despite a few airlines ending certain services including the airport’s biggest user – Jat Airways. Although Jat will end its flights to Gothenburg, Munich, Prague, Tripoli and Malta it will increase frequencies to regional destinations – flights to Podgorica will operate 3 times a day while to Tivat twice daily. Flights to Skopje will be operated on a daily basis, Dusseldorf with 5 flights per week, Trieste 4 times weekly while Milan is newly introduced with 3 flights per week and Thessaloniki will feature in the winter schedule for the first time (twice a week). As a result Jat will operate 161 return flights weekly which is roughly the same as last year.

After Jat, Lufthansa and Montenegro Airlines will operate the largest amount of flights from Nikola Tesla Airport. Lufthansa will operate 3 daily flights to Munich and 2 daily flights to Frankfurt (although it will end services from Dusseldorf which will be taken over by Jat with 5 weekly flights). The Montenegrin national carrier will operate the identical amount of frequencies from Tivat and Podgorica as Jat. Alitalia will operate daily flights to Rome and Milan while Swiss will operate twice weekly flights to Basel (on top of its flights to Zurich). The airline will increase its capacity by upgrading its equipment to an Airbus A321. Meanwhile ČSA will operate daily flights to Prague and Turkish Airlines will increase from 3 to 5 weekly flights from Istanbul.

The airport expects it will have around 865.000 passengers in the 5 winter season months which would see an increase of 5% compared to that period last year when the airport had 824.000 passengers. In total the airport is poised to have more than 2.5 million passengers by December 31, 2008.

A study of physics shows that a body that is free to rotate will always turn about its center of gravity. In aerodynamic terms, the mathematical measure of an airplane’s tendency to rotate about its center of gravity is called a “moment.” A moment is said to be equal to the product of the force applied and the distance at which the force is applied. (A moment arm is the distance from a datum [reference point or line] to the applied force.) For airplane weight and balance computations, “moments” are expressed in terms of the distance of the arm times the airplane’s weight, or simply, inch pounds.

Airplane designers locate the fore and aft position of the airplane’s center of gravity as nearly as possible to the 20 percent point of the mean aerodynamic chord (MAC). If the thrust line is designed to pass horizontally through the center of gravity, it will not cause the airplane to pitch when power is changed, and there will be no difference in moment due to thrust for a power-on or power-off condition of flight. Although designers have some control over the location of the drag forces, they are not always able to make the resultant drag forces pass through the center of gravity of the airplane. However, the one item over which they have the greatest control is the size and location of the tail. The objective is to make the moments (due to thrust, drag, and lift) as small as possible; and, by proper location of the tail, to provide the means of balancing the airplane longitudinally for any condition of flight.

The pilot has no direct control over the location of forces acting on the airplane in flight, except for controlling the center of lift by changing the angle of attack. Such a change, however, immediately involves changes in other forces. Therefore, the pilot cannot independently change the location of one force without changing the effect of others. For example, a change in airspeed involves a change in lift, as well as a change in drag and a change in the up or down force on the tail. As forces such as turbulence and gusts act to displace the airplane, the pilot reacts by providing opposing control forces to counteract this displacement.

Some airplanes are subject to changes in the location of the center of gravity with variations of load. Trimming devices are used to counteract the forces set up by fuel burnoff, and loading or off-loading of passengers or cargo. Elevator trim tabs and adjustable horizontal stabilizers comprise the most common devices provided to the pilot for trimming for load variations. Over the wide ranges of balance during flight in large airplanes, the force which the pilot has to exert on the controls would become excessive and fatiguing if means of trimming were not provided.

Today a colleague (Jani Ylinen, a graphics designer who knows everything about Rhino and Maya) from Nokia helped me out with Rhino a bit. So here is what I learned today.

If there is need to make 2D cross sections of for example of the fuselage, it can be done as follows:

1. Create a rectangular surface.
2. Make rectangular array of it. Adjust proper step to proper direction and use appropriate number of copies. E.g. 100 cross sections, one per each 5 cm for example.
3. Then choose Object intersection. Select all items (the rectangles plus the 3D model that you are going to cut apart)
4. Hit enter and wait that iRhino does the processing. It is slow in the current alpha-version.
5. Move the cross sections to another layer
6. Hide the 3D object layer
7. And you have cross sections. You can export these to in dxf format to for example to Qcad and process them further there. E.g. you can plot them to paper. Printing from Rhino is possible as well, but it prints the zoom level of a view that is currently present, and the scale you get can be about anything (not something that you can repeat for each model and do exactly the same scale drawings on paper each time, does not succeed with Rhino printing capabilities).

Jani also showed how to do radius. Select radius tool, select surfaces and type the radius and hit enter. Magically the radius appears to the piece with amazing accuracy.

There is also a silhouette function that makes a 2D projection out of the wireframe. You can propably utilize that in a 2D Cad, e.g. QCad (or Autocad if you are wealthy enough to have the overpriced licence to that outdated software).

I learned today that actually Rhino can be used for technical drawing without using more traditional technical drawing programs. You need to keep your model history with layers manually (if you change some cross section for example, you need to loft again), but with some work, it seems to be all you need. Also measurements can be handled, but you need to maintain them manually too, if you change some shape, you may need to update your dimension as well. With cutaways with the cross sections and the silhouette function, it seems that all sorts of technical drawing can be done with Rhino. It is different and some things are very manual, but on the other hand, as a bonus, the 3D side is so blazingly good that there is nothing that compares with it in user friendliness and expressivity. You can really create with this tool and about everything is there, you just need to discover all the functions.

Seems like the price-value ratio of Rhino is exceptionally good. With one thousand you can get so nice tool that it actually is better and especially a lot easier to use than overpriced Autodesk tools. This is how the design is done in the future for sure.

I am also downloading the Maya personal edition for Mac now. I plan to try it out for rendering models modeled in iRhino.

Many thanks to Jani for guidance with graphics software. It is very much fun to learn new things.

On October 25, 2008 MAT Macedonian Airlines, the national airline of Macedonia will begin with its winter schedule. As usual for this time of the year MAT will be decreasing its regular frequencies. This winter it will operate flights using 3 aircraft (2 newly leased Boeing B737-500 aircraft and a CRJ-900).

From Skopje MAT will be ending its flights to Amsterdam, Berlin and Hamburg. Flight IN451 was operated once a week to Amsterdam while flight IN320 to Berlin was operated twice a week. Flights to Hamburg were also operated twice a week. Despite this, MAT will continue flights to Germany by continuing services to Dusseldorf which will operate twice a week using a B737-500. Services to Istanbul which were operated 6 times a week will now be operated twice a week using the CRJ-900. Flights to Rome will continue to be operated twice a week using the airline’s both aircraft types. Flights to Vienna will continue operating 5 times a week with a daily code share flight serviced by Austrian Airlines. There will be 11 weekly flights to Zurich with another 2 flights operated in a code share by Helvetic.

From Ohrid the Sunday flight to Vienna will continue to run via Skopje. Flights to Zurich will be maintained once a week while the flight to Amsterdam which was operated via Skopje ends as mentioned above. Currently in the preliminary schedule there is no news of new destinations.

Any related updates will be posted. Any question our readers might have regarding the new schedule can be posted by using the “comments” option or contacting us using our e-mail address. Soon Adria Airways’ 2008/09 winter schedule will be published on the blog.

Carlos from RCAdvisor commented my one post and I decided to check out his site. I created user account there etc. I was really amazed the RC Calculator, it not only has quite amazing features for model makers, but it also seems to have quite interesting animated UI, I didn't know that this kind of stuff can be nowadays done with Java (or is it flash?). I haven't had time to yet surf what all is on this site, but it looks quite comprehensive and promising and I will for sure look further into it. Indeed, maybe I find some tips for the twin concept RC-scale model I am going to do. Thanks Carlos for your link!

the link to the RCAdvisor

Whenever an airplane changes its flight attitude or position in flight, it rotates about one or more of three axes, which are imaginary lines that pass through the airplane’s center of gravity. The axes of an airplane can be considered as imaginary axles around which the airplane turns, much like the axle around which a wheel rotates. At the point where all three axes intersect, each is at a 90° angle to the other two. The axis, which extends lengthwise through the fuselage from the nose to the tail, is the longitudinal axis. The axis, which extends crosswise from wingtip to wingtip, is the lateral axis. The axis, which passes vertically through the center of gravity, is the vertical axis. [Figure 3-9]

The airplane’s motion about its longitudinal axis resembles the roll of a ship from side to side. In fact, CH 03.qxd 10/24/03 6:44 AM Page 3-8 3-9 the names used in describing the motion about an airplane’s three axes were originally nautical terms. They have been adapted to aeronautical terminology because of the similarity of motion between an airplane and the seagoing ship.

In light of the adoption of nautical terms, the motion about the airplane’s longitudinal axis is called “roll”; motion about its lateral axis is referred to as “pitch.” Finally, an airplane moves about its vertical axis in a motion, which is termed “yaw”—that is, a horizontal (left and right) movement of the airplane’s nose.

The three motions of the airplane (roll, pitch, and yaw) are controlled by three control surfaces. Roll is controlled by the ailerons; pitch is controlled by the elevators; yaw is controlled by the rudder.