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Thread: Junkers Ju-52/3m

  1. #151
    Hello Smilo,
    Thanks! I think so too. Anyway, the way I did it this time gave a better
    envelope
    than I was getting before.

    Just for the sake of curiosity to illustrate it, hereīs a compound screenshot
    of the propeller graph Table 512 and the Torque graph for the 725 Hp engine.

    The difference with the other two more powerful engines is a slightly narrower
    "hump", and of course that the right column goes up to 775 and 830 Hp
    respectively, in the torque graph and a less pronounced "step" in the propeller
    graph.

    Note that the "downward hook" on the right is not of the type sometimes used
    for curbing power after max. RPM. Some time ago Ivan had recommended not
    using it,
    to allow for a more correctly defined engine power.

    If I had had an extra column on the right, after the Max. Power RPM setting, I
    would have liked the graph to go on horizontally, but it does that anyway, I suppose.

    Eliminating the "hump" and the "step" causes abnormally low cruise powers at
    correct maximum power, or conversely, abormally high maximum power at
    more correct cruise powers.

    So, perhaps itīs as good as it gets, as Jack Nicholson would say...
    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails Table 512 and torque graph.jpg  
    "Why make it simple if you can also make it complicated?"

  2. #152
    Hello Aleatorylamp,

    The CFS engine dynamics are not perfect. Just do what you can as well as you can.
    I am never satisfied with my own flight models, but realise that at some point, I don't know how to make any more improvements.

    Quote Originally Posted by Aleatorylamp
    Later, the French did the same with their Turbomeca Bastan VIC turboprop turbines, with similar results, although here there was no methanol, just water. They were actually quite successful, and used them on the Nord 262 commuter/navy patrol aircraft for quite some time.
    Eeeek, a Jet!!!

    Regarding water injection on a Turboprop:
    I believe this is the same idea as on a regular jet engine and has nothing to do with piston engines.
    The idea is to use the combustion heat to superheat water into steam for increased exhaust thrust.

    Quote Originally Posted by Aleatorylamp
    What happens with water-methanol injection? I think the engine rusts! ...If used at speeds above cruising, I suppose it would possibly interfere with lubrication and maybe quickly ruin the engine.

    Itīs not such a stupid idea at all, actually, but do correct me if Iīm wrong!

    The impression I got was that interestingly enough, methanol performance increase came with the penalty of greater heat, so they injected water to cool that, also obtaining the added thrust of the steam generated. The drawback of all this was I believe greater corrosion resulting in reduced engine life-span, but for military purposes it wasnīt important.
    Now keep in mind that I am certainly no expert in this field.... but I do not believe you are entirely correct.
    Gasoline as you know is a Hydrocarbon. There are many impurities, but the important molecules are composed of Hydrogen and Carbon. The byproducts of combustion (oxidation) are H2O and CO2. Thus there already is water vapor in the cylinder as a result of combustion.
    The addition of water into the intake system is intended to reduce the combustion temperature and prevent pre-detonation so that higher boost / cylinder pressures can be tolerated without damage to the engine. The higher pressures and stress by themselves will have some effect and I believe this is the cause of increases in engine wear.
    The methanol is just an additive to the ADI mixture to prevent it from freezing when the temperature gets too low.

    - Ivan.

  3. #153
    Hello Ivan,
    Thanks for your comment on doing what one can to best get sim engine performance as near as possible to specs!


    Re. Water-Methanol: Interesting, and unexpected, what you mention, thanks a lot!
    Iīd expected that the superheated steam effect that adds thrust to jet turbines (and I know that it does, and it makes them rust more), would also apply in piston engines, as a logical deduction.

    However, it was just an impression on my part, and I didnīt know that methanol was only an anti-freeze.

    But then, if water and water+methanol is defined as WEP in the sim, donīt these give any added thrust?

    From what you say, it appears not to be the case, and in reality the extra power comes only from a higher amount of fuel being burned, with water and water+methanol addition only acting as a retardant and a direct coolant, to counteract the increased heat of the extra fuel.

    Wikipedia explains all you are saying in great detail, and makes for a very interesting read!

    Then, the difference in the effect between using water and using water+methanol for added power seems to be that although being combustible, methanol has a retarded ignition point and thus helps prevent detonation. Both also seem to allow for higher compression ratios.

    Maybe thatīs why the allowerd WEP time in the sim is longer for water injection only, than for methanol-water, which is only 5 minutes.


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

  4. #154
    Hello Aleatorylamp,

    The WEP in the CFS is gross oversimplification of how things really work.

    Even in the case of US aircraft in which only "Water Injection" is available, the reality is that they used methanol as an additive as well.
    I believe the limit was "5 minutes" but those quote are because that limit was often stated as 5 minutes but sometimes it was not.
    It depended a bit on the engine and some were more tolerant than others.
    Note that the REAL limitation was that the engines would typically be generating more heat than they could dissipate and the Cylinder Head Temperatures would be in a range that could only be tolerated for a few minutes without damage.

    Note that I mentioned specifically CHT which implies radials.
    One of the reasons that Inlines could run for a bit longer by simply raising boost without Anti Detonant Injection (ADI) is because there was more mass to "heat soak": More mass in the cooling system, engine mass, etc. needed to have its temperature raised before bad things started happening.

    The Water Methanol injection I believe was intended to represent the German systems used on the FW 190A series. It is a pity that the FW 190A in the game doesn't actually have that feature. Sometimes the limit was 10 minutes and sometimes it was not.
    Sometimes the emergency power wasn't even MW50 injection at all.

    Life gets really interesting when looking at the Japanese engines because their fuel was so poor (91 or 92 octane) that ADI was required for some engines as soon as their throttle settings went above continuous cruise settings. Thus climb, normal, military and emergency power just differed in allowed duration. All required ADI.

    The 5 minute Supercharger WEP is also not realistic. At low level, it MIGHT be pretty close, but above the critical altitude, the engine even with WEP would be using less boost than it would be at sea level and at some altitudes above that, the engine even with WEP engaged would not be using as much boost as it would under continuous power settings at sea level..... And yet the engine would still blow up after 5 minutes 10 seconds.

    - Ivan.

  5. #155
    Hello Ivan,
    Very interesting information, that you supply, and I appreciate your efforts explaining so many details!

    I had always wondered why the VW Beetle air-cooled engine with 1200-1600 cc had such a low compression ratio that it only produced 30-50 Hp. So it was to prevent over-heating!

    Regarding the simīs aircraft engines, I suppose that it must have been quite complicated for those who wrote the sim, to cater for so many different kinds of engines within the comparatively few choices offered in the .air file.

    Perhaps, given the lower performance of the Pentium I computers in those days, the .air file would have been too demanding on the CPU if further complication had been introduced.

    Anyway, after all the feedback and support Iīve been getting from you and Smilo, I think that within CFS1 limits, the different Auntie Ju models have come out quite nicely, and are performing very satisfactorily!

    Iīm just finishing the Checklists and then Iīll start upload them, the unarmed transport/paratrooper versions first.


    I also have to see about the still inaccurate bombing system that the "improved" bomb sight provided, after they had eliminated the g3eīs retractable under-fuselage "stew-pot".

    That bomb aimerīs position between the wheels, f
    rom what Iīve read, despite a clear view, had a bomb sight that was no good at all for precision bombing, even from the prescribed 500 meters.

    To include the "improved" sight in the model, Iīll see if I can modify the B-17īs bomberīs sight and see if that will work at 500 meters with cruising speed.

    Another thing they did, was just shove thousands of incendiary bomb-sticks out of the cargo-doors!

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

  6. #156

    Spanish and German Transport versions uploaded.

    Hello Folks,
    Here are the first two, which will be available at the following links as soon as they are authorized in the Warbirds library:

    Ju52/3m g5e unarmed transport/paratrooper aircraft:
    http://www.sim-outhouse.com/sohforum...id=19&id=23401

    Spanish CASA352-L transport/paratrooper
    http://www.sim-outhouse.com/sohforum...id=19&id=23400

    I hope you all enjoy the models!
    Any constructive criticism will as usual be welcome!

    As soon as Iīve figured out a bomb sight for the armed versions these will be uploaded as well.
    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails CASA352-L.jpg.jpg   g5e-transport.jpg  
    "Why make it simple if you can also make it complicated?"

  7. #157
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    got 'em, thanks
    sometimes the magic works.
    sometimes it doesn't.

  8. #158
    Hello Aleatorylamp,

    I don't know if your conclusion about compression ratio and heat output in the VW engine are reasonable. I suspect that they are not.

    I believe the biggest issue with the older computers was not the complexity of the AIR file.
    I believe the problem was lack of video rendering speed.

    - Ivan.

  9. #159
    Hello Ivan,
    Water-cooled car engines of the time, with similar cylinder displacement, had higher compression ratio, developing twice the power with the same fuel consumption. The VW engine couldnīt resist the temperatures and pressures involved and would have blown its cylinder heads. I was under the impression that the reasoning behind it followed your line of argument as regards heat dissipation and the engine mass (not the methanol-water injection aspect, of course), quite apart from the weaker and cheaper materials used compared to radial aircraft engines, but then, Iīm not a mechanical engineer, so I wonīt insist.

    As regards the reason for the simīs shortcomings as regards the simplification of the only few different types of supercharging offered, I was actually just trying to be diplomatic and not blame it on the programmers, although they maybe couldnīt do any better as they werenīt aircraft-engine engineers, and although they must have had some advisors in this field, they perhaps couldnīt apply all the details because they possibly a) didnīt understand them completely, or b) thought it wasnīt necessary and just didnīt want to so many in, so as not to complicate their lives). Thus, we get an approximation of what it should be, and must make do with it! Such is life... Anyway, this is only my impression, as I am neither a programmer nor a computer engineer, so I wonīt insist on this either.

    Cheers,
    Aleatorylamp
    Last edited by aleatorylamp; Yesterday at 03:14.
    "Why make it simple if you can also make it complicated?"

  10. #160

    CFS1 bomb dropping - Visual display problems.

    Hello Smilo, hello Ivan,
    Iīm working on the bomb-aimerīs panel and its workings, but Iīm
    having some on-and-off problems with the CFS1 bombing feature:

    Sometimes the graphic bomb-dropping-and-exploding visual display
    from the outside view works, and sometimes it doesnīt - you just
    hear their release.

    The bombs are defined in the Dp files, and show up as loaded at the
    start in the aircraft choice window together with ammo and fuel, and
    after being released they always disappear as expected from this load
    menu, even
    though they are often invisible during a flight.
    Perhaps itīs a bug in the graphics card.


    It happens both in Freeflight mode and in Quick Combat, and Iīve been
    trying to figure out what it depends on, to no avail, so I was wondering
    if you could perhaps suggest something.

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

  11. #161
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    i have a busy day today,
    but, will have a look as soon as i can.
    sometimes the magic works.
    sometimes it doesn't.

  12. #162
    Hello Aleatorylamp, Smilo,

    I believe the issue with bombs displaying probably has something to do with the model format that is generated by AF99.
    The loads do not show up visually and landing gear and propellers do not display properly in AI aircraft nor in multiplayer.

    Regarding air cooled automotive engines, there are other examples such as some of the early Porsche 911's and Chevrolet Corvairs that are not exactly low powered. The turbo Corvair actually made pretty good power though I don't really consider any version of the Corvair to be a particularly good car.
    By the way, I am not saying your conclusion about the VW is incorrect. I don't know much about the VW.... Though I was actually thinking about building one to drive around in CFS.

    By the way, it is a little late, but yesterday I found some very good dimensional drawing for the Tante Ju.

    - Ivan.

  13. #163
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    duh...it just dawned on me...
    maybe, it would be a good idea
    for you to send me the latest bomber version beta,
    including, dp, air and aircraft cfg files.
    sometimes the magic works.
    sometimes it doesn't.

  14. #164

    New WIP: Ju52 + Guns + Bombs

    Hello Smilo,

    Hereīs the latest Ju52 "Gunship" WIP.
    Thanks for your offer to help with the bombs!

    The Bomb Aimerīs panel is still in the adjustment stage:
    I was more or less getting the scale on the panel for map view correctly
    placed for 500 metres = 1600 ft at cruise speeds between 140 and 160 mph
    but could only do so intermittently because the sim kept making the
    explosions invisible. Then, I havenīt adjusted the 1000 metre (3200 ft) scale yet.

    Also, machine-gun option No. 1 defined by the Dp files leaves machine-guns (key 1)
    inaudible in my sim, so Iīve got all guns are defined as cannon, option No. 2 in the
    Dp files, (Key 2), so at least I can hear them. With a bit of luck you can discover a
    possible mistake on my part.

    The .air file is the new one, and F10 gives you full WEP power for 5 minutes:
    830 Hp at Sea Level with 184 mph at 2300 RPM.

    Without WEP you get 658 Hp, 171.4 mph and 2133 RPM, which isnīt bad either,
    and itīll take-off too!
    Itīs actually the max. power of the earlier g3e auxiliary bomber that was used in
    the Spanish Civil War - which I havenīt built.

    Anyway, it would be great if you can check the guns and the bombs -
    I appreciate it very much!

    Cheers,
    Aleatorylamp
    Attached Thumbnails Attached Thumbnails Ju52-g5e.jpg  
    Attached Files Attached Files
    "Why make it simple if you can also make it complicated?"

  15. #165

    Air-cooled performance engine

    Hello Ivan,
    I remember the 911 Porsche from 1969!
    A completely different kettle of fish from the Peopleīs Car:
    2200 cc, 180 Hp at 6500 RPM, normally aspirated, air cooled - wonderful!
    With the price that thing cost, they used better materials than on the ordinary beetle.

    I made an airport pick-up truck for FS98 I could send you. Udo Entenmann did the .air file
    for it and managed to put in a kind of suspension effect, which was quite spectacular.
    Iīve got the AF99 project files, and Iīm trying to find the model with the .air file.

    If I find it I could attach it to a post if you are interested. You could go careening around
    a runway and through a city or around a scenery!

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

  16. #166
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    preliminary dp report;
    at first, i was unable to get the "gunship"
    guns or bombs to function in freeflight,
    or the quick combat modes.
    long story short, i took up the raf662 lancaster,
    and tested it in all flight modes.
    yes, guns and bombs do function.
    instead of bothering with the ju52 dp file,
    i renamed the lanc dp and replaced the ju52 dp.
    the gunship now has tg2 aft firing guns and dropping bombs,
    complete with impact explosions and craters.

    more later
    sometimes the magic works.
    sometimes it doesn't.

  17. #167
    Hello Smilo,
    So it was the Dp files that werenīt functioning properly!
    Thatīs also why only the Cannon were working, not the MGīs.


    How strange, thanks a lot! It wouldnīt have occurred to me!
    It just goes to show, two minds work much better than one!

    Iīll take it from there. Iīll wait for the rest of your "more later"
    report, and then Iīll download the Lancaster and use those Dp files,
    adapting the boxes and bombload,
    and adding 2 lateral firing guns
    to see if I can get those to work with TG2.


    The Dp files for the two already uploaded unarmed paratroopers
    versions
    are derived from the same ones, but without machineguns,
    and with
    paratroopers defined as bombs. So, if these and their explosions
    are
    mostly invisible, it is just as well, as it avoids exploding paratroopers!
    How nice!

    Update: The Dp files I used came from a previous model, which could have
    originated from Dp files someone made for one of my models 14 years ago.
    Maybe this version is incomplete and/or antiquated, and probably, a more
    reliable method would be to use the default Dp Files that come with CFS1,
    and complete those with the functions desired for a given model with Dp Edit.

    Thanks again.
    Cheers,
    Aleatorylamp
    Last edited by aleatorylamp; Today at 09:19.
    "Why make it simple if you can also make it complicated?"

  18. #168
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    "quick" note;
    i'm not sure if the raf662 lancaster is still available.
    but, any bomber dp that works in cfs will do.

    important! make sure you delete the old cdp file
    whenever you make a change to the dp.
    apparently, the sim calls the cdp instead of the dp
    unless it isn't in the individual aircraft folder.
    the cdp will be rewritten after each flight.

    on second thought, here is the renamed lanc dp file.
    when you open the attached dp file with notepad,
    there is a little gift at the top.
    cut and paste it to the bottom of the COMBATFS.CFG
    minus the ///s, of course.
    then, in game, when you release a bomb, look down.
    and see what happens.
    to disable it edit the combatfs.cfg entry to ...trainer=0 instead of =1

    i hope this helps.
    i'm off
    Attached Files Attached Files
    sometimes the magic works.
    sometimes it doesn't.

  19. #169
    Hello Smilo,
    Thanks for your support and your reminders.

    Iīve just tried out the Ju52 bomber version with CFS1 default Dp files,
    and they work perfectly, so itīs evidently not my computer or the
    graphics card which is at fault.

    Thanks for the files youīve just posted. (Yes, I couldnīt find the Lancaster...)
    Iīll look into them report back later. Most probably they will be easier to work
    with than to have to adapt whole new Dp Files using the default CFS1 ones.

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

  20. #170
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    glad to hear the default dp worked.
    i didn't think of that.
    i'm not sure if the lanc dp would be easier to work with.
    either way, the boxes will have to be adjusted.
    i'll leave that to you.

    if one was curious enough,
    one could open the original nonfunctional ju52 bomber dp
    and the lanc or default dp side by side and compare.
    find the difference, find the problem.
    more or less
    sometimes the magic works.
    sometimes it doesn't.

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