Douglas A-20 Havoc Project
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Thread: Douglas A-20 Havoc Project

  1. #1

    Douglas A-20 Havoc Project

    Hello Folks,

    During an E-mail exchange with Smilo, he mentioned one of his all-time favourites,
    the Douglas A-20 Havoc, so I asked him if heīd like me to make one with AF99.

    His enthusiastic "Go ahead!", has prompted me start collecting the necessary information
    to start building, and I found quite a variety of different versions.

    So, Smilo:
    You mentioned starting off with a version without the dorsal turret, so the question
    here is whether there should be glass there or not. Also, I suppose you mean no ventral
    gun either.

    Then, thereīs the question of the nose: Non-glazed with 6 machine-guns, or glazed with
    no guns, or perhaps only two?

    There seems to be quite a variety of possibilities on this model.

    As regards engines, thereīs 1600 Hp and 1700 Hp ones, so for a start weīd have to find
    out which type of engines will go on the initial model. I have engines for both, from the
    time we made the Baltimore series.

    So, we have a plan! Great stuff!

    Cheers,
    Aleatorylamp
    Last edited by aleatorylamp; August 21st, 2020 at 01:53. Reason: grammar
    "Why make it simple if you can also make it complicated?"

  2. #2
    Hi Smilo,
    Thanks for sending all that material. A great help.
    What Iīd managed to find is about a quarter as good!

    At the moment Iīm scaling the drawings, and then Iīll fire up the conveyor belt for
    an initial A-20C model without the rear gun turret.

    Even though it had a glazed bomberīs position in the nose, it seems to have had 4
    large MGīs in the nose, two on each side, ensuring a good punch!

    Cheers for now,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  3. #3

    Phase 1: Preliminary trials

    Hello folks!

    The model has progressed from the drawing board to the conveyor belt,
    for a preliminary mock-up, to test for dimensions, shapes, texture spread,
    and .air file performance.

    Wings and tail are as yet only 2D panels, and fuselage is still made of
    structures with AF99 "oval" cross-sectiones, but will later be made of
    components.

    Glazed nacelle, cockpit and aft gunnerīs glazed position are on the textures
    for now, later to be made transparent.

    However, the model has started getting the look, which is nice for building,
    to get the feel.

    A simple, textured and animated landing gear is also implemented, as are
    engines and propellers.

    According to specification, the Havoc A-20C had R-2600-23 turbocharged
    engines, and with 7 machine-guns had the following top performance:

    At 13000 ft: 342 mph, 1600 Hp, 2600 RPM
    Sea level : 314 mph, 1350 Hp, 2600 RPM

    On the model, the .air file is now giving me:
    At 13000 ft: 343.7 mph, 1347 Hp, 2590 RPM
    Sea level : 315.0 mph, 1602 Hp, 2590 RPM

    So this seems to be quite satisfactory for a preliminary initial stage.

    Now thereīs at least something to show! For those interested in watching
    how
    the model takes shape, Iīve attached the Work In Progress model,
    and included
    a few screenshots. It looks like one of those coloured tin toy
    airplanes 50 years ago!


    Cheers,

    Aleatorylamp
    Attached Thumbnails Attached Thumbnails Havoc prelim 1.jpg   Havoc prelim 2.jpg   Havoc prelim 3.jpg   Havoc prelim 4.jpg   Havoc prelilm blueprint.jpg   Havoc prelilm blueprint1.jpg  

    "Why make it simple if you can also make it complicated?"

  4. #4

    A fin glu glitch, and WEP MP possibilities

    Hello Folks,

    Terribly sorry, there was a glitch in the fin glu - it was a line instead of a triangle,
    and caused the tail fuselage to bleed through the 2D fin ( of course)...

    Well, I fixed the fin glu, and also the fin is now 3D.
    Hereīs the corrected Havoc Preliminary Phase 1 W.I.P. model, and 2 screenshots!

    Also, a thought about having WEP in the flight dynamics:
    On the Baltimore, we had 5-minute WEP for Take-off power WEP, which was an
    additional 2 inches of mercury MP over the normal max. continuous MP of 42 inches.

    At the moment, I put in all the specified 44.3 inches max. MP, but I was thinking of
    doing something similar as on the Baltimore, i.e. normal MP at 42.3, plus 5-minute

    WEP with an extra 2 inches of MP. ...or maybe 42 plus 2.3...

    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails Finglu.jpg   New fin.jpg  

  5. #5

    Phase 2

    Hello All,

    A bit of progress: Now wings and stabilizers are 3D components, no longer made of cardboard...
    I was surprised at the thickness of inner wings, and I needed several tries to get it right.

    Also, the fuselage was 10% too wide, but thatīs corrected now - it appears to have been quite
    a slim 4 ft in width. It is still done in structures, with glazed parts on textures, but that will be seen to in the coming Phase 3.

    Then, I have made a small adjustment in the engine supercharger, and have separated 100 Hp
    (2 inches of mercury Manifold Pressure) to GET type-2 WEP for 5-minute Take-off power and battle, similar to what we had on the Baltimore.

    This still seems a very good solution, as it makes it easy to fly with Military Power at max. throttle without WEP, and press F10 for WEP at Take-off and in battle.


    Please find attached screenshots and the new model for those interested in trying it out.

    Now comes the difficult building part: Fuselage conversion into components with glazed nose, cabin and dorsal gunnerīs position with their corresponding framework.

    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails Havoc-Phase2-1.jpg   Havoc-Phase2-2.jpg   Havoc-Phase2-3.jpg   Havoc WIP-2 Blueprint1.jpg   Havoc WIP-2 Blueprint-2.jpg  
    "Why make it simple if you can also make it complicated?"

  6. #6

    Slight improvements

    Hello Folks,

    I found a cleaner way of grouping/gluing the engine nacelles and wings.
    Previously Iīd had nacelles glued to outer wings in Wing Mid Right/Left,
    and then the inner wing component in Innerwing Mid left/Right, but noticed
    slight bleeds at the inner nacelle area.

    It turns out that a more efficient distribution is having engine nacelles glued
    to the inner wings in Innerwing Mid left/Right, where the bleed interference is
    lower, and doesnīt worsen the bleeds in the outer wing/nacelle area.

    Then, the stabilizer panels are now better as well, without momentary disappearances.

    Also, forward engine nacelles are now grouped with the propellers in Nose Left/Right,
    using the convenient Left and Right Nose/Wing templates,
    and Iīve just fixed a
    last-minute left spinner sequencing problem just now, which can be seen on one
    of the attached screenshots...


    Hereīs the new Havoc WIP Nš.2 model, attached again.
    I just noticed Iīd deleted WIP-2 yesterday instead of WIP-1, silly mistake...
    so itīs just as
    well that hereīs the improved WIP-2. Ever so Sorry!

    Update: I noticed thereīs a mistake in the engine nacelles at the upper wing
    area - nacelles donīt portrude as much as I have them portruding, so thatīs
    the first thing to fix just now...

    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails nacelle re-grouping.jpg   nacelle grouping2.jpg  
    Last edited by aleatorylamp; August 30th, 2020 at 04:03.

  7. #7

    Wing thickness

    Hello All,

    With the Wing thickness problem now solved, it appears that the outer
    wing/nacelle bleeds have increased.

    This remided me of the Tigercat, still a WIP-model due to bleed problems.
    Although the wings seemed OK, there were bleeds with wheel doors and flaps.
    Iīll have to look into these again, because the model is stuck on that.

    I hope things wonīt get stuck on the A-20 because of bleeds, as the layout
    of nacelles, wings, flaps and wheeldoors is rather similar...

    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  8. #8

    Fuselage work

    Hello Folks,

    Tha Havoc has now got a fuselage made of components, and just now Iīm working
    on the
    canopy frames. The rear gunnerīs is done, the cockpit now needs a floor,
    and the
    forward canopy frame is in the making, as you can see on the screenshots.

    You can also the guide-line in the front. Then will come all the glazing work and the
    glue
    sequences to get the crew in. That will be a lot of fun! I like glue sequences.
    Itīs fun when youīve been taught how.

    The livery is still very Martin-Baltimore-like, but the model will soon get its 5-pointed stars!

    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails Havoc component fuselage.jpg   Havoc component fuselage2.jpg  

  9. #9

    SSD death

    Hello Folks,

    Spanner in the hardwearks, Iīm afraid, and itīs taking its time to put right.
    At the weekend the SSD played its tedious and confusing disappearing trick
    in the BIOS again.

    Normally, after a few cable plugging and unplugging the hardware all got going
    again, but this time it also involved OS-corruption with physical internal SSD
    errors, which led to a one-way ticket into the trash-can.

    I donīt know if the BIOS malfunction is the cause or the result of this hardwreck,
    so things may get worse instead of better after sorting out a conventional HDD for
    the OS and then retrieving development material.

    At any rate, it is going to take some time until work on the Havoc can continue.

    Cheers for now,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  10. #10

    Hardware Issues

    Good Luck on resolving the BIOS / SSD issues.
    Is it possible that you might need to replace a battery?

    Sometimes hardware failures take a long time to fully manifest themselves.
    It took about 3-4 years from the first sign of trouble in my old Development Machine until I had a complete Motherboard failure with smoke effects and all. During that time, there were just intermittent failures and sometimes programs didn't seem to do what they were supposed to do and sometimes the machine did not boot.

    Is it possible you are having a similar problem if a drive does not detect and sometimes the drive gets corrupted? In other words, perhaps the problem is in the motherboard rather than the drive?

    SSDs are fast, but I don't have a lot of faith in them. Then again, my Daughter has had a very lightweight laptop with an SSD for 5 years now and although there have been problems with the other hardware, the SSD seems to have held up.

    - Ivan.

  11. #11
    Hello Ivan,

    Itīs OK, I looked at the new battery part in the summer when the SSD started its disappearing acts after power cuts or forced shut-downs after hanging, so it isnīt the battery.

    Iīve read about the older SSDīs, and it appears to be a bug in their firmware, that now has been put right for new SSDīs.

    Apparently, power cuts erase the SSD SATA Port number from the BIOS, so the BIOS assigns a new one at random, and it takes quite a few SSD cable un-plugging and plugging into a different port until it coincides with the new number. Quite crazy, if you ask me - it never happens on normal HDDīs, so this idiocy has made the little faith I had in SSDīs fade away.

    Anyway, I had managed to correct the problems I had this summer, but this time the SSD is flawed, even though four different SSD-scanning programs report no faults. At any rate, Iīm not about to buy a new SSD, despite the improved firmware nowadays!

    Now Iīve put WinXP onto a relatively new traditional big 7200 RPM HDD, and installed FS98, AF99 and AA, and things are functioning flawlessly for three days now. It isnīt as fast as before - start-up takes 58 seconds instead of 10, but so what!

    The next thing is to put CFS1 back in, gather up the different add-ons like the SCASM disassembler-assembler and the special editor it needs, which will eventually get done!

    Cheers, and have a nice day!
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  12. #12

    Time to continue: Change-over to a solid nose.

    Hello Folks,
    Itīs time to continue. Sorry about the long delay...

    The glazed nose up front was getting very tedious, causing complications and boring delays,
    so I have opted for an initial version with a solid nose, and building work has fortunately been
    resumed.

    Apart from the easier-to-build and elegant-looking and smooth nose shape, the tremendous
    advantage of this solid-nosed version is the incredible fire power of the numerous nose
    machine-guns.

    The basic model itself is done, pending the rear gunnerīs glass and some adjustments in the
    pilotīs cabin area. When they are done, Iīll post a new WIP update.

    For the moment, hereīs a screenshot.
    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails Havoc-new-nose.jpg  
    "Why make it simple if you can also make it complicated?"

  13. #13
    Hello Aleatorylamp,

    Just out of curiosity, which model of Boston / Havoc is this supposed to be?

    - Ivan.

  14. #14
    Hello Ivan,

    Here is a document I put together with the evidence for one of these models.
    Apart from this one, there seem to have been some units of this kind that
    served in Russia.

    Note that the provisional textures on the model in the screenshots at the
    moment are adapted from the Baltimore, and are not accurate for the Havoc.

    Update: Here are some screenshots of Russian and American Havocs with
    solid nose and without a turret for the rear gunner, so there will be at least two
    liveries available for the model.

    Cheers, and have a good weekend!
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails havoc1.jpg   Havoc2.jpg   Russian Havoc-1.jpg   Russian Havoc-2.jpg   Russian Havoc-3.jpg  
    Attached Files Attached Files
    Last edited by aleatorylamp; November 14th, 2020 at 03:25.
    "Why make it simple if you can also make it complicated?"

  15. #15
    Hello Aleatorylamp,

    My guess is that you probably have more choices for markings than that, though I haven't confirmed it.
    By the time the early A-20G was in production, Lend-Lease had been in effect for some time and I would be surprised if some deliveries did not end up in RAF or RAAF service.

    Check your service ceiling. This is not a space shuttle! ;-)
    Your specifications are also for a A-20G-45 which is a much later block and equipped with the power turret in back.

    - Ivan.

  16. #16
    Hello Ivan,

    What power would you say was correct? Do you mean those had 1000 hp engines?

    I thought early units with solid nose and rear gunner position having no power turret
    would be the DB-7A/Havoc II, and would have the 1600 Hp engines.

    Then I found the following, so it could very probably be a "G" model:

    "The A-20G, with 2850 units delivered as of Feb. 1943, had the glazed nose replaced by a solid nose with four 20 mm (.79 in) Hispano cannon and two .50 in M2 Browning machine guns. After the first 250 units, the unreliable cannon were replaced by more machine guns. Some had a wider fuselage to accommodate a power driven gun turret. Many A-20Gs were delivered to the Soviet Union. The power plant was the 1,600 hp (1,200 kW) R-2600-23."

    So it appears that not all "G" models had the power turret...

    Cheers,
    Aleatorylamp.
    "Why make it simple if you can also make it complicated?"

  17. #17
    Hello Aleatorylamp,

    This is a pretty good reference:
    http://www.joebaugher.com/usattack/a20_17.html

    So anything in the G-5 to G-15 production blocks would match what I believe you are looking for.

    I was just pointing out that the listing you had was for a G-45 which is a much later block and differs a bit in armament....
    and that 725,000 feet service ceiling was just a bit too high.

    - Ivan.

  18. #18
    Hello Ivan,

    Nice document, thanks! OK then with the 1600 Hp and the liveries on the photos.
    I think Iīll provide the Russian No. 16 and the American J-DU liveries.

    725,000 ft! Ha ha! For a moment I thought the .air file gave stratospheric behaviour...

    I had only scan-read the text that came with the photo I found and put into a .doc file
    to attach to that previous message, so I missed the Star-Wars ceiling!

    OK then. Iīm just working on the glue sequences for the cabin and gunnerīs position.
    Letīs see how it goes.

    Have a nice Sunday,
    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  19. #19

    Ready for a second WIP model

    Hello Folks,

    Now the fuselage has the correct shape, and there is a solid nose after issues I had with the glazed one, and I have managed transparent, inhabited cockpits for pilot and rear gunner.

    Itīs strange one canīt exactly replicate glue sequences for models with similar crew and cabin layouts. There are always small dimensional differences that require slight changes in the sequence.

    There is still an annoying bleed from the rear cabin bulkhead that I have to see to, and some gaps at the wingroot and hairline cracks in the tail-fuselage also need attention.

    Geardoors, gearwells, the deadly 6 nose-guns and ventral gun are still missing, and textures are still provisional.

    Nevertheless, current progress could warrant a second WIP, so here it is, for those interested to enjoy. Comments as always, will be welcome.

    Update: The cabin bleed is cured now, with re-arrangement in the glue sequence, but I have just noticed cabin-glass bleeds through wings and engine nacelles - of course, being set in Canopy High Wing, itīs not high enough to clear the wings, so Iīll have to put it into the Body Main sequence. Letīs see...

    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails Havoc-a.jpg   Havoc-b.jpg   Havoc-c.jpg   Havoc-d.jpg  
    Last edited by aleatorylamp; November 17th, 2020 at 06:57.
    "Why make it simple if you can also make it complicated?"

  20. #20

    Canopy improvements: WIP Model 2a.

    Hello Folks,

    I managed to re-group the canopy glass for the pilotīs and gunnerīs positions,
    and have achieved improvements. The cabin glass is not 100% perfect yet,
    but itīs much better. One Glue-template angle here played a key role.

    Also, I think there was an FS98 .air file in the WIP 2 attachment I uploaded this
    afternoon, but thatīs now superseded by this one.

    Here is a WIP 2a Havoc model version, now also including source files should anyone
    feel inclined to have a look inside.

    Enjoy, and Cheers,
    Aleatorylamp.
    "Why make it simple if you can also make it complicated?"

  21. #21

    Update: WIP model No. 3

    Hello Folks,
    There has been some progress in the construction of the A-20 Havoc.
    AF99 Parts Count is now at 145.4%, and the model is slowly approaching completion.
    Now it has flaps, 6 nose guns, the ventral gun, wheel doors and wheel wells.
    Attached is the WIP-3 model and 2 screenshots, and as before, it includes source files.
    The following work is still pending at the moment:
    > eliminate some flap bleeds
    > general textures
    > removal of a few hairline cracks
    > adjust dp files
    > ...and anything else anyone would like to point out.
    Hopefully I can finish the model for Christmas or New Year.
    Meanwhile, enjoy the WIP update!
    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails A-20 Havoc.jpg   A-20 Havoc-2.jpg  
    "Why make it simple if you can also make it complicated?"

  22. #22

    Now with air-intake scoops. Update: WIP-4 Model

    Hello folks,

    Iīve managed to complete the model with the supercharger scoops on
    top of the engine nacelles, and also reduce flaps and geardoor bleeds considerably.
    Itīs going rather well, so here are a few new pictures, and also a WIP-4 update.

    Textures, SCASMed Virtual Cockpit and hairline cracks are still pending.

    Update: Oops! I just saw flaps are of the wrong type and will have to be cut out
    of the wing instead of fitted beneath.

    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails A-20 Havoc-3.jpg   A-20 Havoc-4.jpg   A-20 Havoc-5.jpg  
    Last edited by aleatorylamp; December 2nd, 2020 at 08:45.
    "Why make it simple if you can also make it complicated?"

  23. #23
    Hello Aleatorylamp,

    Fitting plain flaps instead of split flaps is going to be a serious pain this late in the game.
    One of the nice things is that texturing will be simplified over split flaps.

    - Ivan.

  24. #24
    Hi Ivan,

    Yes, as nicely as it was going and now it isnīt!
    I thought Iīd been lucky with the split flaps. What a goof!

    With a parts count now of 149.4%, plain flaps are going to be, like you say, a pain.
    Wheels, struts, fuselage, wings, tailplane, canopy frames, windows, have eaten up all
    30 components, and none of the 28 structures left can be converted.

    Flaps will have to be individual panels each, which in itself should be no problem.
    Hopefully the outer wings with cut-outs now will not have textures bleeding over inner
    corners with extended flaps.

    I had already reduced nacelle bulkhead vertices from 12 to 10 to free parts for the
    scoops, which went fine, and now Iīll have to eliminate maybe 2 bulkheads from the
    nicely rounded fin structure, which is a pity.

    Another bore is that on the real plane there were bits of wing on trailing edge nacelle
    sides adjacent to flaps, and maybe those will have to go.

    Anyway, letīs see how it goes.
    Cheers,
    Aleatorylamp
    "Why make it simple if you can also make it complicated?"

  25. #25
    Hello Aleatorylamp,

    I had figured out pretty early on when I started working on my own A-20 Havoc many years ago that it wasn't going to be a simple AF99 project with the level of detail that I wanted. My main problem was that the references didn't seem to agree in basic dimensions. Many dimensional drawings and even specifications in the manuals were simply wrong.... More on that later if you are curious. My visual model hasn't progressed to any great degree, but the amount of documentation I how have is at least 4-5 times what I was working with back then.

    Remember where we started with the Eric Johnson P-39D? That project also made a pretty similar mistake in putting plain flaps in a P-39 though of course it is much easier to fix that kind of a goof than to ADD plain flaps afterward.

    Good Luck.
    - Ivan.

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