Experiments to Learn
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Thread: Experiments to Learn

  1. #1

    Experiments to Learn

    Here is another old project that fits pretty well into the Diversion category.
    This FW 190D-9 AFX was done by Alex Simon and seems to be the basis for numerous FW 190D and Ta 152 projects out in the CFS menagerie.

    This is not the first time I have looked at making corrections to this project.
    While the basic appearance of the finished aircraft especially those with textures by Hugh Shoults actually looks pretty good, there are plenty of hidden boogers that are very hard to correct.
    From what I can tell, folks working with this project haven't generally tried to make any great corrections to it other than to move the Supercharger Intake from the Port to the Starboard side more typical of a JuMo engine.

    As far as I am concerned, this project is pure experimentation and will never lead to a release of any kind.
    If I want a FW 190 with an inline engine, it will be a conversion of my own FW 190A project.
    At least there, I have a pretty good idea how big the can of worms is before I open the can.

    This AFX was done before the rather casual SCASM edits we now throw in without much thought.
    There are a few almost hidden parts near the CoG of the Model that are textured to almost provide a virtual cockpit.
    I say "almost" because they don't really align with the other pieces of the model but at least they don't leave the model looking like a hollow shell in Quick Combat. Some of the other FW 190D based on this AFX actually use this feature.

    Since I know that SCASM works better for the purpose, I decided to remove these pieces.
    This brings up another bit of strangeness with this AFX and the zip file containing it.
    Although the Assembly had the Parts and they were textured, they did not show as textured in AF99.
    Also, the textures that were used by these pieces were not included in the zip file.
    I could easily pull them from any number of other FW 190D downloads, but thought it was such a goofy way of doing things, that it was not worth the effort.

    I decided to simply remove those pieces from the Assembly.
    One might notice in the screenshot that nothing is animated.
    This is because in removing those virtual cockpit pieces, the model was changed enough that Aircraft Animator no longer recognizes the pieces it is supposed to animate.

    This brings up another point. Has anyone else wondered how Aircraft Animator recognizes pieces that it needs to animate?
    I found out a year or two ago that it is actually by the SCASM label for the pieces. (!)
    As long as the AF99 edits don't change those labels, prior animated pieces will be recognized (mostly).

    So why am I still wasting time on a project that I know will go nowhere?
    There are a few things that are done in this project that I never do on my own projects.
    I can experiment with those features to see if I can improve them to the point where they become a reasonable thing to add to my own projects. If I fail and damage something, it was a throwaway project anyway and these assemblies tend to be much less complicated than ones in my projects.

    It is also very satisfying to make a few simple changes and see some noticeable improvements.

    - Ivan.
    Attached Thumbnails Attached Thumbnails AlexSimon.jpg  

  2. #2

    Updates and General Experiments

    A few additional pieces were added to this model:
    Flap Wells, Landing Gear Wells, the Pilot was added a while back.
    The Supercharger Intake was also moved to the correct side for a Jumo 213 engine.
    The Flaps themselves are a bit more complicated now.
    Earlier they were textured the same as the trailing edge of the Wing.
    That meant that the inside of each Split Flap was the same as the Wing Upper Surface.
    Those surfaces normally don't carry camouflage paint so this was certainly incorrect.

    In playing with the propeller animation, I found that this flight model was basically that of a FW 190 with a radial engine.
    The Jumo 213A that was developed for the Engine Tuning Tutorial was installed in its place and now I am finding that the Propeller is quite inadequate to handle the level of torque and power that the new engine is giving.

    This seems like a good enough model to use to develop a flight model for the FW 190D.

    - Ivan.
    Attached Thumbnails Attached Thumbnails TestFlight.jpg  

  3. #3
    Yesterday, I went into the "Library" and found a couple really good references for the FW 190D-9.
    One of the references is in German and my reading is extremely slow.
    The other is in Japanese and I can't read that at all.

    One had some good dimensional drawings which are almost certainly good enough to convert my FW 190A into a "Dora".
    In the drawings, I found that the propeller diameter that I had been using was almost certainly incorrect.
    Correcting the diameter actually puts the Propeller Power Coefficient much lower which altered the Idle Speed but didn't change the engine output.
    There was other information that needs to be reconciled for the flight model and THAT may mean that the current JuMo 213A-1 needs a slight rework for power levels. It won't change that much, so it makes better sense to do this after a proper propeller with Wide Virtual Blades (Higher Power Coefficient) has been built for this engine.

    After finding the "correct" Propeller Diameter in the drawings, I noticed that the Propeller Diameter in the visual model was off by slightly over 6 inches. This took about 30 minutes to correct. Perhaps I should check other critical dimensions as well.
    The drawings also showed that the piece of armour to protect the pilot's head and back is missing from the model although the headrest and support are present.

    Attached are screenshots of the corrected propeller.

    There seems to be a lot of variation in the equipment installed in the Dora-9. Some had outboard wing cannon. Some did not. Some had the ETC 504 weapons rack and some did not. Some were conversions from the A-8 series "Wrack"s and had the earlier non-blown canopy with the older canopy supports and some had the newer solid support more typical of a A-9/F-9 or ground attack birds.

    My flight model thus far is somewhat contradictory. It has MW 50 for a power adder but also has the 115 Liter Aft Fuselage Fuel Tank. Either the Water Methanol OR the 115 Liter Fuel Tank could be installed but not both. Since I still plan on using the standard FW 190A Fuel Selector, I may just convert the Aft Tank into the small Priming Fuel tank that was also present. The details still need to be worked out.

    That is the reason for working with a throwaway model. All the mistakes get to be made here.

    - Ivan.

    - Ivan.
    Attached Thumbnails Attached Thumbnails CorrectedPropDiameter.jpg   CorrectedPropBlur.jpg  

  4. #4

    Dimensional Problems

    The 6+ inch Propeller diameter discrepancy should have been a pretty good indicator that there might be other issues.
    I was about to make some corrections to partitioning of Components in the Fuselage and also add the missing Armour behind the Pilot and decided to do a quick check of overall dimensions. The results were surprising.
    The overall length is 3-4 inches too long, and the wing span is nearly TWO FEET (actually 1.78 feet) too long. This is some of the easiest information to get before starting a project but it doesn't seem like it was ever done here.
    Very disappointing.

    - Ivan.

  5. #5

    Partial Fixes

    It turns out that the Wing Span was actually 1.80 Feet too long.
    I decided to try a fairly low effort fix.
    The screenshots show an intermediate stage. (I haven't finished the fixes yet.)

    The Wing Tip and Ailerons were combined into a AF99 Component which I called X1.
    I then used the CMoveIt (Component Move It) Utility I wrote a few years back to shift the entire Component Inboard by 0.90 feet and Down by 0.07 feet so that the Parts would telescope into the Inboard Wing Section.

    The Wing Tip Chord is also a bit too short, so the Wing Tip X1 Component will be slightly magnified (by around 3.5%) to better match the lines of the inboard section.
    This won't actually correct all of the size issue of the Wing Tip Chord but it will be closer than it was before.
    A proper correction would require a full rebuild of the Wing and I have no intention of putting that much work into this project.

    There are also some discussions which suggest that the Overall Length of the FW 190D-9 is actually longer than typically reported.
    The length of this model would still be a bit long but is probably not worth fixing.

    - Ivan.
    Attached Thumbnails Attached Thumbnails TelescopeWing.jpg   NewWingSpan.jpg   Mismatch.jpg  

  6. #6

    Corrected Wings

    The Wing Tip and Aileron (combined into Component X1) was stretched Longitudinally by a factor of 1.032.
    There were no changes in Vertical or Lateral dimensions. After that, the adjusted X1 Component was moved to match the inboard Wing section.
    This was a very simple process using command line utilities once the degree of adjustment was determined for each stretch or shift.
    After that, a reference Part was created from the end of the Wing inboard section and Wing Tip and then a Station Template was created which was the average of those two Parts.
    Once the Parts of each Wing Component were adjusted to match the new Station Template, the task was basically done except for moving the Pitot Tube to match the new Wing Tip. A bit more measuring, three calls to utilities and that task was also done.

    Texturing for this model is extremely basic and was not hard to correct. It still is not optimal, but is no worse now than it was before except that the crosses on the Wings are very slightly more distorted.

    - Ivan.
    Attached Thumbnails Attached Thumbnails Stretch1032.jpg   CorrectedWings.jpg   Fixed Wings.jpg  

  7. #7

    Center of Gravity Shift

    One of the odd things about this project is that the Center of the Model is at the tip of the Spinner.
    This can be seen in some of the prior screenshots from AF99.
    The odd location is corrected by a shift of the Center of Rotation by 9.9 Feet.

    Personally I do not like this arrangement. I prefer to have a Model built with minimal (or ideally no) shifts.
    This seemed like the perfect opportunity to use the tools that I programmed when working on the Eric Johnson P-39D.
    Things went off without a hitch..... Almost.

    It seems that many of the Parts files in this project have rather long names with embedded spaces.
    This obviously causes some problems with utilities that operate on command line parameters.
    It took about an hour longer to work around that problem. (About 3 failures before finding a solution)
    The old animated pieces were still recognized when going through Aircraft Animator, so very little additional work was needed.

    Last night was also the first time I took Dora up for a general test flight.
    The impression was not so good.
    While the Aeroplane has a pretty large surplus of power and some serious engine torque as expected, general maneuverability and handling is extremely poor. Roll rate is pretty average.
    While the Dora was known to be less maneuverable than the earlier radial powered Aeroplanes, this wasn't just a little worse, it was simply bad.

    I am not about to throw out this AIR file just yet. It is still interesting to see how and where it can be fixed.

    - Ivan.
    Attached Thumbnails Attached Thumbnails ShiftedCG.jpg   ShiftedCG&Paint.jpg  

  8. #8

    JG57 Dora-13

    Many many years ago, I worked on a few projects with the crew of JG57.
    I was never a formal member. I have an aversion to committing to organizations but there were several of their aeroplanes I was involved in doing mostly visual model adjustments with.

    I don't believe their FW 190D-13 was one of them but I thought this was a pretty good opportunity to make a few corrections to an aeroplane with a few features that have always bothered me a bit.
    With the edits to Alex Simon's FW 190D-9 that have already been done, most of the fixes are already in place.

    The first step was to see how well the textures of the Dora-13 would map to the Dora-9.
    The first screenshot shows the original JG 57 FW 190D-13.
    The second screenshot shows the textures mapping directly to the modified Alex Simon FW 190D-9 without modification.
    The mapping order was quite a bit different but that was no surprise.

    The JG 57 Bird probably still retains the attempt at a virtual cockpit that is sitting inside the Fuselage center at 9.9 Feet behind the Spinner Tip.
    I removed that in modifying the D-9.
    The D-13 also has a textured rotating Propeller Blur.
    I use a different method of representing the Propeller Blur in my version and it doesn't use a texture file.
    The D-13 doesn't have a Pilot.
    One of my changes was to add the Pilot from one of my P-40's to this project. He didn't really want to take on the task so he still wears his old AVG Leather Jacket.

    Without any additional work, the following items were corrected:
    The Landing Gear Braces no longer bleed through the Wings and Fuselage from odd angles.
    The rather odd bleed at the upper Nose of the Aeroplane has gone away.
    The Coolant Radiator is no longer rotating.
    The Propeller Diameter is now 3.500 Meters instead of a bit over 12 Feet as in the earlier model.
    (In reality to be completely correct, the Propeller of this model will need to be adjusted to 3.600 Meters Diameter or a bit over 11.81 Feet because the later Dora-12 and Dora-13 used a different model Propeller and Spinner.)

    I haven't done any significant reworking of the AIR file of the Dora-13 but was noticing that the weight was way way too low.
    I figure it was off by around 700+ Pounds. A quick and not particularly accurate correction was made to see if it would correct a strange tendency to pitch down.

    Up to this point, I had not really looked at the DP files of either the D-9 or D-13.
    In looking at the D-13, I found some serious strangeness.

    First of all a little background may be in order:
    The Dora-9 originally started with pretty much the same armament as a FW 190A-8 with 2 x MG 131 Cowl MG and 2 x MG 151/20 in Wing inboard positions and 2 x MG 151/20 in the Wing outboard positions.
    With the same armament, the Dora-9 was considerably heavier than the A-8 and A-9 because the Jumo 213 was a much heavier engine /radiator combination.
    Later Dora-9 had the outer wing cannon deleted.
    This change made the Dora-9 about 100-130 KG lighter than the late model A-8.

    The Dora-12 was intended to be the next production model.
    It had a two stage supercharger in the Jumo 213F and a revised Propeller Pitch change mechanism that allowed installation of a Motor Cannon. (The earlier 213A had oil lines running through the bore of the Propeller Shaft.)
    The two Cowl MG were removed and a MK 108 was installed firing through the Propeller.

    The Dora-12 never reached production because of shortages of he MK 108 30 mm cannon.
    Instead, the Dora-13 was designed with a third MG 151/20 mounted as a Motor Cannon with 220 rounds of ammunition.

    In checking out the DP, I found that the locations of the guns on the D-13 were way too far forward and that although the description in the AIR file correctly specified a 20 mm MG 151 Motor Cannon, the DP file used a 30 mm MK 108.

    I never had a chance to test fly after making these adjustments, but I suspect that shifted a few hundred pounds of ammunition about 7 Feet aft should cure the pitch down tendency.

    - Ivan.
    Attached Thumbnails Attached Thumbnails JG57_D13_Original.jpg   JG57_D13_Updated.jpg   AftDeckBleed.jpg   BleedPossiblyFixed.jpg  

  9. #9

    Dora-13 Updates

    The FW 190D-13 had a slight remodel over the last day or so.
    The Propeller is now the VS-9 version with a diameter of 3.600 Meters.
    The Engine is still the not-quite-correct Jumo 213A power range though.

    My original weight estimate turned out to be about 110 Pounds too high if the Zero Fuel Weight is calculated with only a half load of MW50. If it is calculated with a full load, it is about 50 pounds too low, so it was definitely in the correct range.

    The Spinner is now a touch shorter for the cannon blast tube.
    Even with the shorter Spinner, the D-13 with its updated Supercharger was 4 mm longer in OAL.
    It is not reflected in this model. It is slightly shorter than the model of the D-9 though it is probably longer than the actual aircraft.

    Reshaping the upper Nose / Fuselage area was a bit tougher than expected. The naming of Parts was very strange and unpredictable. Of course when one has their own system, every other Designer's naming convention is just wrong.....

    I believe this is a pretty serious improvement in appearance over the original.
    Now we just have to work on the flight performance which was the main objective of this project.

    - Ivan.
    Attached Thumbnails Attached Thumbnails D13.jpg  

  10. #10

    Instrument Panel

    As part of the experiments, I thought it would be worthwhile to edit a proper Panel for the Dora.
    The panel from the stock FW 190A seemed to be a good start.

    To be honest, I had never really taken a good look at this panel other than for aesthetics.
    When I was doing development work on the flight models, I was using a Test Panel.
    When I assembled the package, I just presumed that MS had done things more or less correctly.
    My old Development Computer also didn't really allow me to fly with the control panels being displayed because of the serious frame rate hit. In testing, it wasn't so much of an issue because the numbers being displayed were more important than the stuff in the background.

    For the FW 190D, I figured I would just take the stock FW 190A panel and add a Trim Gauge, add a Magneto Switch which for some reason is missing and swap the Cylinder Head Temperature Gauge for a Coolant Temperature Gauge.
    Surprisingly, there isn't a CHT Gauge on the panel at all.

    Regarding the missing gauges:
    The FW 190A actually did have both a Magneto Switch and a CHT gauge, so I am not quite sure why they were left off the stock panel.
    The Magneto Switch is located on the forward part of the Left console.
    The CHT gauge is on the lower row of gauges and slightly to the left.

    Borrowing a Mag switch from the stock Messerschmitt is pretty easy.
    Programming a CHT gauge probably isn't hard, but I have yet to find a good image of what the face of the German gauge looks like.

    - Ivan.
    Attached Thumbnails Attached Thumbnails FW190A_Panel.jpg  

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