While I just started using dropbox (because one of my university projects required me to use dropbox), it’s gonna take awhile to update all the broken links with the new dropbox links. So, in the mean time, I would like you to use my referals and install the dropbox so that I can increase my file size quota:D. Here is the link for my dropbox referal:

zerocross_raptor’s dropbox referal

Well, I think this concludes my notification for the broken links in my toolboxes. I hope that I can get it all fixed by this afternoon.

Regards,

Stepen

So, here goes my resolution for 2012:

• Master C, C#, and/or C++. Yup, as you all may know, I’m pretty confident in my programming skills in MATLAB. I can do pretty much everything using MATLAB: doing standard numerical calculations, controlling hardware, creating CFD codes, creating games, creating 3D animation, and so many other stuff. Unfortunately, in UAVindo (a technology company that I currently work in), MATLAB is, well, underestimated and they seems to be doing everthing in C#. So, I think why not learning C# and maybe also the sisters: C++ and C. There is no wrong in learning something new, right?
• Have 5-10 more code in my MATLAB Aerodynamics Toolbox.
• Have 5 more code in my MATLAB Fun Toolbox.
• Have 2 or 3 more files in mathworks file exchange (MATLAB Central)
• Finish my unfinished debt for this blog. Yup, if you are jobless enough to follow this blog, you may noticed that I have several promise that I haven’t been abble to fulfill yet, such as the AeroPong, the MATLAB Flight Performance Toolbox, and other stuff (which I have forgotten, haha). I hope that I can finish them all in the first semester of this year.

Well, I think that’s all that I’m gonna do for year 2012. I hope this isn’t too much and I can meet this resolution. Now, off to my MATLAB and let me say Happy Lunar New Year to you all!!!

Regards,

0X_R

So, here is several screenshot of my MATLAB snake code (The graphic is a disaster and I’m gonna improve it later):

MATLAB Snake – Screenshot 1

MATLAB Snake – Screenshot 2

MATLAB Snake – Screenshot 3

MATLAB Snake – Screenshot 4

MATLAB Snake – Screenshot 5

I’ve also uploaded a (bad quality) video of my MATLAB snake in youtube. Here is the video if you want to see the animation that I made for this code:

As usual, this code is free for you all and can be downloaded from my MATLAB Fun Toolbox. Please feel free to download it and give any comments or critics. FYI, for the next code in my MATLAB Fun Toolbox, I’m gonna write MATLAB Congklak code. It is a traditional bean-counting game from my country. However, I think it is gonna take awhile to finish the code because the algorithm is quite complex for the AI and I want to incorporate a pretty nice animation to make the game look nice. Please look forward to it:D…

Regards,

0X_R

Using DATCOM is pretty easy. You just need to create an ASCI text file named for005.dat, write the parameter of your aircraft configuration in it (of course according to DATCOM’s rule), and execute the DATCOM program. DATCOM will instantly calculate your aircraft’s aerodynamic stability derivatives and write it in for006.dat. Unfortunately, since both the input and output are text files, it is quite hard to see whether the aircraft configuration written in the input files is correct and the same with the configuration that wanted to be evaluated. Mistakes in the values of some parameters due to typo,  misinterpretation of parameter definition, or carelessness may still enabling the program to work, but it yields results for different aircraft configuration other than what was meant. And since there aren’t any visualization or GUI, the only solution is to check the input file patiently and carefully.

For a guy like me, I’m always feeling a little insecure in doing manual check of the input file because you can’t guarantee that you won’t miss a thing. On the other hand, I’m also feeling insecure if I’m not checking the input file. As the result, I constantly rechecks the input file for every 5 minutes, even though the output file seems already correct. Since I know that I will be using DATCOM again in the future and I can’t afford to recheck the input file every time, I decided to save me the trouble by creating a MATLAB code that will read the input file and draw the aircraft from the configuration parameters written in it. This way, I can view the aircraft first to ensure that I’m entering the correct values for each parameter in the input file (and I can sleep soundly in the night, knowing that my input file is correct).

So, starting from 6 November last month, I started learning about textscanning and textreading in MATLAB and started drafting the code. The progress of this code development is quite slow because I also have other jobs to do to feed my self (and because I also went to Manado for vacation). Thankfully, early this week, the code was done. I’ve tested with several DATCOM input files that I have and the result was pretty good. Here are several drawing results from the input files that I have.

drawDATCOMaircraft’s result for test file 1 (PSK-01 Walet)

drawDATCOMaircraft’s result for test file 2 (Unknown)

drawDATCOMaircraft’s result for test file 3 (ZLIN-142)

drawDATCOMaircraft’s result for test file 4 (ASW-20)

drawDATCOMaircraft’s result for test file 5 (Boeing B737)

drawDATCOMaircraft’s result for test file 6 (Ercoupe 415C)

drawDATCOMaircraft’s result for test file 7 (P-51 Mustang)

As usual, I’m going to share the code in ths blog. However, I realized that I can’t put this code in my MATLAB Aerodynamics Toolbox page because it is not about aerodynamics. I guess I’m gonna create another new toolbox pages. It may be Aeroutility Toolbox or Aircraft DEsign Toolbox, but I haven’t decide it yet, so I haven’t put this code in this blog. However, I figured that a lot of people is using DATCOM and this code may help them to check their DATCOM input file. I tried my luck and post this code to MATLAB file exchange center and it got accepted. So, while waiting for me to create the new toolbox, you can get the code (Draw DATCOM Aircraft code) from the MATLAB file exchange center.

Well, it’s already 4PM in my time, so, I’m gonna stop the announcement here and go straight to my bed and take a nap:D. I hope the code help and as usual, all critics and comments are welcomed.

Regards,

0X_R

Since this video contains wing flap movement throughout approach and landing phase (and the activation of wing spoiler during braking), I thought that it might be a good idea to post this video also in this blog. Why is it a good idea? Because I can use it to explain the phases and procedure of an aircraft’s landing and the science behind it. So, here it is, a video of Garuda Indonesia’s B737-300′s right wing during approach and landing phase.

As you can see, after descend to a certain altitude for approach, the flaps (the moveable wing part at rear area) were extended and deflected. However, the flaps weren’t deflected to its full extent, yet. After the aircraft was close enough to the runway, the flaps were then fully extended and the aircraft slowly descended and then touched down. Right after the touch down, wing’s spoiler (the moveable wing part at the center area) was deployed while the engine’s thrust was reversed to slows the aircraft down (not shown). When it was slow enough, brakes were also applied to the landing gear to help stop the aircraft (also not shown).

The process of aircraft landing seems simple from the video. However, for every action done in the video, it has its scientific reasoning in it and in this post, I’m going to explain the reasoning behind it. I hope you understand, so, here it is:

Aircraft’s wings generate lift force porpotional to its airspeed, hence, faster speed means more lift. However, during landing phase, an aircraft must be approaching the runway as slow as possible because it needs to brake and stop after landing. Consequently, to compensate the loss of airspeed, wing’s flaps are deflected, causing wing’s chamber (and also its lift coefficient) to increase. This way, the wings will still be able to provide enough lift force for the aircraft although it is moving slower. Gradually, wing’s flaps are extended as the aircraft slows down until it reaches what so called approach speed and the wing’s flaps are fully extended. At this time, usually, the aircraft is already very close to the runway and it is ready to land.

During the airborne phase in an aircraft’s landing, the wing’s flaps are already fully extended while the aircraft will keep slowing down. Thus, to maintain the lift force, the aircraft’s nose is raised up. This way, wing’s angle of attack increases and causing increase in both lift force (which is needed to keep the aircraft fly) and drag force (which is desired because we want to slow the aircraft down). Then, comes the tricky part: touching down the aircraft.

In landing, aircraft’s altitude is decreased by slowing down the aircraft (Remember, lift force is proportional to airspeed). However, decreasing aircraft’s altitude for touch down must be done slowly or the aircraft will land hard. This is where pilot plays with both engine’s throttle and aircraft’s angle of attack to slowly bring the aircraft down. This process is actually very hard. I, myself, have tried landing several aircraft in X-Plane and only had a few successful landing. Mostly, I landed hard or I bounced back and flied up because I was being too careful.

After the aircraft touched down, wing’s spoilers are immediately deployed. This is done to distrupt airflows arond the wings, causing wings to no longer produce lift to avoid the aircraft flying back up again. On the other hand, the deployment of wing’s spoilers also help slow down the aircraft because it causes flow separation, hence increasing aircraft’s drag force.

During this ground phase, the aircraft needs to come into a full stop to finish its landing. However, because of its speed and massive mass, thrust reverser from aircraft’s engines is deployed first to further slows down the aircraft before brakes is applied to the landing gears. If the brakes are applied first, the landing gears may skid. Thus, a thrust reverser must be deployed first to further slows down the aircraft. After it reaches a certain speed, brakes may be applied to stop the aircraft and after the aircraft stop, the landing phase is technically completed. Later on, the aircraft usually taxis to apron to unload its cargo and passenger.

Fiuh… I think that’s all to tell you about the aircraft’s wings during approach and landing. I hope that I wrote it well so it is understandable for everyone (even for those who are not familiar with aerospace engineering). For the next time, I think I’m gonna make a video about aircraft’s wing during take-off. However, I don;t know when I will got on an aircraft again, so you better not get your hopes high. In the end, I hopes that this post is useful for you.

Regards,

0X_R

This is the first set of pictures (that I took in my flight to Manado). It is Garuda Indonesia’s Boeing B737-800NG.

This is the second set of pictures (that I took in my flight back to Jakarta). It is Garuda Indonesia’s classic Boeing B737-300 (and yeah, it does not have any winglets).

I do realize that my photography skill is somewhere between monkeys holding a digital camera so your bad critics about these pictures is expected (and anticipated).

Regards,

0X_R

Othello is a pretty common game. It is about placing black and white chip in a 8×8 board but when you place your chip, your chip must block the opposing-color chip so that the opposing chip swaps into your color. The game play itself is pretty simple but there are a lot of strategies in it and it is pretty fascinating. That’s why I decided to create this game.

Using my TicTacToe m-file as the template for its gameplay algorithm and it GUI, I finally finished this code (the Othello code) last night. Unfortunately, I haven’t have the time to search for the best AI (Artificial Intelegence) algorithm for the computer as the opponent. So I just made the computer to choose a move that give the most swapping for every turn. No strategic move or anticipation for the next turn. That’s why the computer will be fairly easy to beat if you know the basic strategy of playing Othello (for example, trying to get the box at the board’s edge and so on). However, I’m planning to improve it later on (and I hope I do:D). For now, I’m just gonna wrap it up and here is the screenshot of my Othello code:

MATLAB Othello – Screenshot 1

MATLAB Othello – Screenshot 2

MATLAB Othello – Screenshot 3

To make it nicer, I incorporated a simple animation when the color swapping takes place. The chips will gradually change color from white to black or vice versa. Here is the video of me playing my code to show you the animation that I incorporated in my code. I’m sorry for the bad quality though, because I took this using my cellphone. (Yeah, I’m too lazy to find a decent screencapturing software).

As usual, this code is downloadable from my MATLAB Fun Toolbox page. Your critics and comments are extremely wanted, especially for the AI of the computer. Lastly, I want to say that I hope you enjoy the game:D.

Regards,

0X_R

Five days ago, 5 October 2011, I had my thesis defense. My examiner was Dr Tatacipta Dirgantara and Dr Djoko Sardjadi. My thesis defense started at 2PM. After approximately 20minutes of presentation, the examiners began to asked me questions and the defense started. Dr Djoko Sardjadi was the first to asked question. He asked so many question about the flapping wing experiments while on the other hand Dr Tata just aked one question about the concept of window deformation technique. After about one hour of Q&A, My defense ended and I was announced graduate with overall score of 87/100, which means an A. (Yeah, I’m a master of aerospace engineering!).

Just today, I submitted my thesis and a CD containing all of my thesis data and with this, my master study is officially ended. Now I just have to wait for my graduation at either 28th or 29th of October 2011. So, now I can safely say that this log will be my last thesis log.

Now that I’ve graduated, I’m officially not a student, but a jobless man. To tell you the truth, I’m still confused to decide what am I gonna do. An offer for doctoral study was given to me but I’m not sure whether I want to take it or not because I think that my competence is not enough to do it. What I have in mind actually is doing several project at campus to increase my competence and then take another master course abroad. Unfortunately, both my advisor and my examiner laughed really hard when I told them about my plan to take another master course. They said that it was a waste of time and tat I should just take a doctoral course instead. On the other hand, my parents want me to have a normal job and a normal life, the one that is safe and secure. So, now, I’m completely confused with what to do.

While I haven’t decided yet which path that I will take, there is only one thing that I’m sure: I’m not gonna stop learning. There is also one thing that I’m sure of: I’m gonna be active again in this blog and add more codes to my MATLAB Aerodynamics Toolbox and MATLAB Fun Toolbox. I’m also gonna share my thesis and the code that I made for it (but for this, I’m gonna have to check ITB’s policy first). I’m going to make a page dedicated for my thesis. I hope I can have it run by this week:D.

Well, I think that’s all I’m gonna write for this post and final thesis log. With this, I would like to thank everybody that had helped me directly or indirectly in finishing my thesis. Now that I’ve asked for your good luck for every thesis log, in this final thesis, I’m gonna return the favor and say thank you very much for your support. Friends and reader, I love you all…

End of Log

After two bloody month of doing PIV experiments (and not posting anything in this blog), I finally finished my thesis. Well, actually, it is not quite finished yet. I have done my thesis seminar (It’s like an open presentation) and it turned out quite well. However, I still have to face the upcoming thesis defense at 5th October and my writing might be subjected to revision. So, let’s just say that it is almost done and let’s pray that I can do my defense well and get an A.

So, right now, I have quite much very time considering that I only need to do minor revision from my seminar. I have spent the last few days helping undergraduate student to graduate and avoid getting drop out. I also have spent the last two days having fun with my friends and my girl. So tonight, I’m gonna get back to my thesis and do some simulation and image training for my upcoming defense. However, before moving on to it, I decided to tell you this, so that all of you know that I’m still alive and will be updating this blog again.

Since I’m going to do some simulation for my defense, I might as well tell you a brief explaination about my entire thesis in this post as a start (and because I haven’t tell anything in detail about my entire work from the past thesis log).  So, here goes:

In my thesis, I developed two codes in MATLAB. The first code is DPIV image processing code and the second code is force determination code from DPIV measured flow field. After I developed these codes, I did several evaluations to make sure that these code works correctly. Both quantitative and qualitative evaluations were done. Lastly, I conducted several simple DPIV experiments to investigate flapping wing on continuous hovering flight and to apply my codes for real experiments.

As for the DPIV image processing code, I created several m-files in MATLAB with several GUIs to load several images and process those images to obtain velocity field at all time instances. My code implements continuous window shifting and first order window deformation to improve its accuracy. Quantitative evaluations were performed to assess the code’s general accuracy, its subpixel displacement handling, and its robustness to high velocity gradient and the results show that my code performs well than the previous code developed in my lab (Yay:D).

For the force determination code, I also created several m-files in MATLAB and a GUI to read velocity field at all time instances (from image processing result) to measure fluid dynamic force acting on the body inside the flow field. Evaluations were done by using data from CFD simulation and from real DPIV experiments provided by Suryadi (2011) and the result was satisfactory. It is also found that my code is less sensitivy to the selection of domain of integration for force determination (Yay again:D).

To apply both codes, several simple DPIV experiments were conducted to investigate flow field around flapping wing in a continuous hovering flight. An arduino code and a MATLAB script m-file were written to control wing’s motion while acquiring images at the same time. Several diffuculties were found, mainly because of the inappropriate laser used for my experiment. Nevertheless, the experiments were performed successfully and the codes has been successfully applied. A brief analysis on the flow fields resulting from the experiments and codes aplications was also given.

Fiuh… There, I’ve said it. That’s  it, all that I have done for my thesis. I hope I write it in such way that everybody understand. Now its time to close my IE and open up my powerpoint presentation. As usual, please wish me luck on my thesis defense.

End of Log

It turns out that the files that are shared and uploaded in the MATLAB file exchange center are not just an arbitrary code. Every code submitted was reviewed before it is posted online. So, I thought I’d give it a try and submitting one of my code. I looked at several files to see which code that has been published and after several thought, I decided to post my potential flow simulator code, because no one has done it.

Tweaked Potentiallow2DSim_GUI.m Screenshot 1

Tweaked Potentiallow2DSim_GUI.m Screenshot 2

Tweaked Potentiallow2DSim_GUI.m Screenshot 3

So, long story short, I tweaked my potential flow simulator code a bit and submitted it yesterday morning to be reviewed. Actually, I wasn’t expecting much because all the code posted there were good and I thought I’d fail. However, this morning I checked my mail and found out that my code got accepted. So I decided to tell you guys to share my happiness (and to boast myself a little:D). Here is the page for my 2D Potential Flow Simulator code. Please check out the page and leave a comment:D.

Since this code go accepted, I decided that I’m gonna submit more of my code to the MATLAB file exchange center. The next code that I have in mind is the source panel method code. However I’m gonna tweaked a little bit first before I submit it so that it looks better:D.

Well, I thinks that’s enough for today. Now off to shower and then off to campus…

Regards,

0X_R

NB: Although the code is submitted to MATLAB file exchange center, you can still download it from my MATLAB Aerodynamics Toolbox page.