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Rizon

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About Rizon

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    Cape of Storms

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  1. Perhaps pearlescent acrylic paint will work in 1/72, most art shops I frequent have some or other variant that can be painted / sprayed over any previous acrylic colour. Some of them have very fine "flakes", or what ever it is that gives it the luster. Always wanted to give that a try.
  2. In days gone by, when I was doing post-graduate studies and my best mate was building hours for his Com license, I was the preferred extra weight for cross country navs ( I knew about flying a bit, something of nav, but more importantly was single and could work flexi hours, so no one to nagg when am I going to be home etc...). Most of the nav sorties we flew at night, in those beautifull summer or winter nights the Cape of Storms (Soutn Africa) can give. Our plane of choice: Piper Tomohawk. So, taxying out one evening in Cape Town International a BA 747 ends up behind us on the taxiway. We get take off clearance and as we rotate the 747 gets clearance to line up and depart. With a strong warning (advice) from the tower to watch out for wake turbulence from that departing Tomohawk.... Cool, calm and collected read-back as ever from the BA captain "copy cleared for take off, alpha departure, caution Papa Charlie wake turbulence, thank you and good night"
  3. Recently I had a chat with a F-35 test pilot, the guy who gave the first non-US demo at Fairford a few years back. Apparently when being strapped into an F-35 you wont know if you are in the A, B or C model, unless you twist your head to the 6 o'clock position and try to figure out if the lift fan is installed or if longer / folding wings are there. They all fly the same and Billie himself often does fly all 3 variants in the same day and there is hardly ever a need to conciously take note of which one you fly. That is ynless you fly VTOL or carrier ops ofcourse.... R
  4. If I may ad my 2c worth of putting things to focus.... I have been involved in more than one reverse engineering effort of an aircraft, which involved everything from pen and ruler measurement to top end photogammetry and LIDAR. And it is not a trivial whizz bang process to get the geometry right. My particular case was to engineer a wind tunnel model, so aerodynamic accuracy was CRITICAL to say the least. As wonderful as LIDAR is, it gives you a point cloud, ie a collection of points in XYZ space. Now this information has to be processed to turn it into a surface ( like a NURBS surface, STL wont do) and that in turn into a "solid model" that CAD can understand for further processing into useable components. The fitting of these surfaces is difficult to say the least. Even as LIDAR gives you millions of data points to work with, acurate fitting is still the focus of much, much research in reverse engineering circles. Especially in areas whrere the rate of curvature (like at the leading edge of the wing) is high, do the biggest errors creep in. Then there is also the rendering of the CAD model. As simple screenshot from a CAD program does not convey the true geometry in my experience. It depends entirely on the graphics processing, and other things like screen resolution etc. One will have to "play" with the model interactively to get an idea and actually do further measurements on the CAD model to understand the geometry. And even further there is the fact that something will have to be manufactured in 1/72 scale and injection moulded with preferably only two mould halves. On said wind tunnel model the thing had to be machined from marraging steel and selected parts 3D printed in titanium - all at the large scale of 1/12.5. The approximations that one has to do even at that scale caused many heated debates - with valid reasons all around. So now try to do that a 1/72 and keep everyone happy (dare I say every arm chair modeller...?) I for one applaud Airfix's efforts. I hope the guys there have fun. I certainly did, even though years later I still dream of data points and the Hawk geometry....
  5. Nice to see there is another Aerodynamicist here! Gruß R
  6. Rizon

    PC-9 / Texan II

    The two pictures of the "kinked" tail are actually PC-7Mk2 aircraft, now called PC-9M. The PC-7Mk2 was developed from the standard PC-9 for the SAAF in the early 90's. The "7" was used instead of the "9" in the designation due to the downrated performance, and a good dose of politics.... As to the differenced between the original Swiss and the American built version: plenty. Canopy is larger and has the alteady mentioned extra frames. Also note the spinner is bigger and thus the whole air intake and nose have some slight differences. Different ejection seats too and the ventral fin difference.
  7. Normal automotive brake fluid, usually the cheapest works best (not synthetic one, that dont work). I prefer brake fluid over other chemicals as it does not smell strongly and is easy to apply and sticks to the surface, as it is oil. Takes a night or so to work on the paint and glue. It also makes the plastic a bit brittle if left for more than 2 days. Clear parts also frost a bit, but is quickly polished out. Of course it is also important to then clean the parts afterwards with detergent to remove the remaining brake fluid. R
  8. Awesome, great to see someone with a similar mission to mine... Currently I am dissassemblying and cleaning a number of models built whem my skills were not all that good. I usually use break fluid to remove the paint, as it also desolves the glue joints.
  9. "Libelle" is the more commonly used word for dragonfly. R
  10. Nice build! I actually found mine easy to build; the trick is to add a few extra location tabs to force the parts into position. Built mine in aabout a week. Painting was however another issue, lots and lots of gloss white!
  11. I was fortunate to attend the OT&E in the SAAF as a civilian a few years back. Course members were mostly fighter and helicopter pilots. During one lunch the conversation turned to forced landings. No one had done a real one, and everyone was dreading the concept. I cassually observed I already did 52 forced landings. 9 pairs of saucer big eyes stared at me.... Untill I mentioned all of them were in a glider, however there was a awe that remained with the fellow students.
  12. Well done on the weathrting! Well balanced and characteristic of the real weathering patterns.
  13. I think the colours are actually very close to an operational aircraft. The "dark earth" bleached quite a bit. Just a sugestion: you can try to slightly town down the colour even more by adding a very light mist of pale grey once all decals are on and the matt coat is on and dry. I have the same kit, built many years ago, which is up for restauration due to the brown being dark earth and not the actual lighter shade. So I'm following with interest....
  14. Giving me ideas with the air brake.... Well done! If you do find that article, please post? Will appreaciate it much. I am a bit of a sucker when it comes to moving parts on models R
  15. If I may chirp in here... Refering to the test fits of the VGs on the wing: note that the VG's are mounted at an angle of about 22 degrees (if memory serves me correctly) relative to the longituinal axis. Since you are going into that insane amount of detail.... Interesting also, at least on the Hawks that I had to measure up, is that the bit of the angle that gets stuck to the wing surface is sometines inboard and sometimes outboard. Always consistent per airframe, but different accross the fleet. The exact spanwise position also varied. However the chord-wise position is perfectly fixed. Interesting approach to your modelling detailling - you are setting a verry high challenge for the tripplet of Hawks I am planning. This is a fascinating thread, keep it going! R
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