Bahnbus-Mod für den O305G

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  • I have the engine performance chart for the M-B OM 407 hA if you are interested, as my own O 305 G has this engine.


    The final drive ratio would likely be 5.409:1 as in practice, buses fitted with this ratio with a good engine can can achieve 85-90 km/h. The standard ratio of 5.921:1 is good for only 75 km/h or so.


    Hi and thanks. I've got the performance charts myself in a brochure from an exhibition in 1978 and the values in the engine_constfile should be correct. I chose the final drive ratio for a roughly 85km/h top speed, as apparently Omsi doesn't calculate correctly and the bus would be far too fast with the correct value. As far as I remember Mercedes claimed that the articulation control is working reliably up to a speed of 95km/h but no O305G was able to go that fast with the factory adjustments.
    According to the aforementioned brochure the following final drive ratios were available: 6.734, 5.921 and 5.263, the latter most likely only in combination with either the OM407hA or the 4-speed gearbox with a very low 1st gear. I think this Bahnbus version is almost too powerful and accelerates too fast too, which might be down to Omsi again not calculating for example driving resistances correctly. It's fun though

    ;-)
  • Hi and thanks. I've got the performance charts myself in a brochure from an exhibition in 1978 and the values in the engine_constfile should be correct. I chose the final drive ratio for a roughly 85km/h top speed, as apparently Omsi doesn't calculate correctly and the bus would be far too fast with the correct value. As far as I remember Mercedes claimed that the articulation control is working reliably up to a speed of 95km/h but no O305G was able to go that fast with the factory adjustments.


    The following was extracted from the performance charts that I have:



    Zitat

    According to the aforementioned brochure the following final drive ratios were available: 6.734, 5.921 and 5.263, the latter most likely only in combination with either the OM407hA or the 4-speed gearbox with a very low 1st gear. I think this Bahnbus version is almost too powerful and accelerates too fast too, which might be down to Omsi again not calculating for example driving resistances correctly. It's fun though

    ;-)


    I understand that there are many combinations possible. I have seen O 305s with O 405 diff centres, O 405s with O 305 diff centres and so on. My own O 305 G has an unusual specification with a 4.203:1 final drive to allow for a top speed of 110 km/h. My city also at one stage had 3-speed 240hp O 305 Gs with the 5.263:1 final drive delivered new in 1979-80. These were adequate for our generally flat topography and allowed them to be used on freeway services. Later deliveries (1986-7) were 3-speed 280hp units with 5.409:1 final drive and performed much better. Regarding OMSI, I find that the achievable speeds are quite close to the numbers that you can calculate manually, and even a little bit lower than expected. Just for reference, an O 305 with a 5.22:1 final drive has a theoretical top speed of 87 km/h at 2,200 rpm and the same bus type but with a final drive of 5.937:1 has a theoretical top speed of 75 km/h.


    I should note also that the O 305 Gs with third-party bodywork in Australia are much heavier than the ones built in Germany. My own O 305 G has a dry weight of 14,820 kg.

  • Thanks again for the information. I'm going to include the engine_constfile with the correct torque values in the next update, but so far there's no plan to upload one just for this one file.
    In order to reduce the maximum speed to about 85 km/h I had to choose a 5.1 axle ratio. Or am I missing something?
    I don't know anything about diffs from the O405 in the O305G axle (I would assume that the axles were more or less identical anyway) but also don't forget that the diff is only one factor of the final ratio, as the reduction hubs add to it and they were available in different ratios too. The O405 series had smaller wheels which had to compensated by a different geared final drive (of which the wheels themselves are a part too, of course). I'm absolutely sure that your final drive ratio was never available in Europe in the O305G, even the O307 had a maximum speed of only 98km/h with its fastest rear axle (and so did the O407 and O408 ).
    The vehicle weight has got no impact on the maximum speed by the way, at least as long as the road is totally flat. It only takes longer to get there

    ;-)
  • Thanks again for the information. I'm going to include the engine_constfile with the correct torque values in the next update, but so far there's no plan to upload one just for this one file.
    In order to reduce the maximum speed to about 85 km/h I had to choose a 5.1 axle ratio. Or am I missing something?


    Based on 5.263:1 being the final drive ratio, I am seeing roughly 85 km/h with the governed speed set to 2300 rpm.


    Zitat

    I don't know anything about diffs from the O405 in the O305G axle (I would assume that the axles were more or less identical anyway) but also don't forget that the diff is only one factor of the final ratio, as the reduction hubs add to it and they were available in different ratios too. The O405 series had smaller wheels which had to compensated by a different geared final drive (of which the wheels themselves are a part too, of course). I'm absolutely sure that your final drive ratio was never available in Europe in the O305G, even the O307 had a maximum speed of only 98km/h with its fastest rear axle (and so did the O407 and O408 ).


    The diff centres on the O 305-series and O 405-series are interchangeable. Also, the diff centres on MAN SL 200/SL 202s are interchangeable with Mercedes-Benz ones.


    Regarding the tyres on the O 405-series, you are correct, they are generally smaller than the ones used on the O 305-series (the steel wheels themselves are actually the same). My O 405 (as seen in my display picture) was actually constructed with 'regular' 11R 22.5 tyres as found on the O 305-serie but other O 405s in my group have 11/70R 22.5 tyres. Smaller tyres indeed have a 'gearing down' effect so you lose roughly 10 km/h with that change alone. Also, generally, the O 305/O 307s were offered with 4.768:1 as the tallest final drive ratio option, which in practice is good for about 100km/h.


    Zitat

    The vehicle weight has got no impact on the maximum speed by the way, at least as long as the road is totally flat. It only takes longer to get there

    ;-)


    Absolutely correct. I thought that I'd add that comment anyway just out for interest.

  • The lorry and bus axles and engines used by Mercedes and MAN in the 70s and 80s in their heavy duty buses and lorries have been developed in cooperation for the use in vehicles for the German army. The engine blocks and cyinder heads are interchangeable (within limits), at least on the basic engines. MAN cared for the horizontal and vertical straight engines and the V10 while MB got all the other V-engines (V6 and V8) as well as the 6-cylinder in-line underfloor engines. MB never used any vertical engines of that type in any of their vehicles while MAN never had V6 and V8 engines derived from this cooperation. The rear axles were indeed more or less identical and interchangeable.
    In the 90s the concept became watered down, the use in the army never materialised in the intended way (in fact only in the MAN CAT trucks and very few MAN SR buses) and so both manufacturers went their own ways and developed new engines out of the existing block (MAN D2866, MB OM457) and reused the existing rear-axles or modified them for the use in low-floor buses. With the introduction of high-strength steel there was no need for the reduction hubs (which had been introduced to keep the size of differential and drive shafts down) anymore (which, strangely, Volvo and Scania never had any use for; Magirus did though) and the 3rd (4th if you count Standard-II and 1st lowfloor generation as two) generation of buses and also of most trucks haven't got those expensive and heavy axles anymore. Both manufacturers still use them on HD trucks, MB for the strongest Actros and both for their tipper chassis.


    Anyway, to get back on topic: even if the governed speed is 2300/min, the maximum power is reached at 2200, beyond that the power is going down towards zero within 100/min. That means the maximum vehicle speed is reached when the engine is doing 2200/min. I tested in Omsi and there I was only able to maintain the maximum speed of 85 km/h with the chosen axle ratio, no matter what the bus would do if calculated on paper.

  • Bus stop brake. I already have a good recording of the park brake valve on my own O 305 G which you can use if you want.


    That would be nice.


    Regarding the bus stop brake: apparently different valves have been used, the one currently used for the Bahnbus Mod is the one I remember the most, but I know there's at least one other without that double hiss. Your Australian buses are probably the furthest away from the standard O305G (if there ever was something like a standard) and have most likely been adapted to common technology in your part of the world, which might include the use of valves and other components from brands not known or not very common here in Central Europe or in fact in Germany. The UK is already very different, and that's just around the corner.
    The park brake has to sound different because of the four (instead of two) park brake cylinders and two instead of one relay valve for their operation.


    I'm looking forward to your recordings!

    :-)
  • Hi,


    ich bin heute mit dem Bahnbus 305G auf Winsenburg 2015 unterwegs gewesen.


    Leider schildert er kein einziges Ziel auf Winsenburg. Habe die Installationsanleitung befolgt und alles in den OMSI-Hauptordner gezogen , sodass er die einzelnen Ordner richtig eingefügt hat.


    Bei anderen Karten schildert er die Ziele ordnungsgemäß.


    Weiß einer Rat?


    Liebe Grüße


    Marcel



  • Ich gehe davon aus, dass die hof-Datei keine Rollband-Ziele enthaelt. Die hof-Datei, die mit der Mod kommt, funktioniert definitiv. Am besten entweder die komplette Mod nochmal neu installieren oder nur die hof-Datei aus dem Archiv in den Hauptordner vom O305G entpacken und die dortige Winsenburg_2015.hof ueberschreiben lassen. Bitte auch checken, ob das Verzeichnis vehicles\anzeigen\Rollband_O307_V2\Winsenburg_2015 exisitert und Dateien enthaelt.

  • Du meinst die komplette Mod? O305 waren bei der Bahn noch seltener als O305G und ich habe sie selber nie erlebt, so dass ich da keinerlei Beruehrungspunkte habe. Machbar waere das allemal, aber nur fuer den StUELB (sprich: E2H84/85), da es die VOEV-Front bei der Bahn nicht gab. Hier gibt es dann jedoch kleinere Stolpersteine wie die Trilex-Raeder (austauschbar) und die Laengsbank vorn rechts (nicht austauschbar). BVG-Eigenarten muessten fast komplett bleiben.
    Klingt interessant, ich spiele mal ein wenig und gucke mal wie weit das machbar waere. Das waere sicher auch interessant fuer Ruhrau/Velbert.


    Wenn es nur um den Sound geht, das ist einfach.


    Wie einfach

    :)

    Könntest du's erklären? Wär nett

  • Wie einfach

    :)

    Könntest du's erklären? Wär nett


    Einfach ist immer relativ. Erklaeren ist nicht so ganz trivial. Wenn du dich selbst hineinfuchsen willst, guckst Du Dir am besten die Sound_O305G_DB_T.cfg aus dem Sound\Bahnbus-Verzeichnis an und im Vergleich die diversen Sound_O305xxxxx.cfg


    Ich kann ja mal eine zusammengebastelte Bahnbus-Version vom O305 zusammenstellen, das dauert aber dann auf jeden Fall noch. Das kann aber wirklich nur ein grosser Kompromiss sein, denn der E2H, der die Basis bilden muesste, ist kaum umbaubar. Sitzanordnung und -anzahl, Rollbaender, Armaturenbrett, Tuersteuerung etc muessen bleiben wie sie sind.

  • Mir ist aufgefallen, dass die Beschleunigung - gerade im ersten Gang - etwas zu harsch ist. Da müsste eine Drehmomentlimitierung rein. Das ist eben noch ein Problem bei OMSI in Bezug auf drehmomentstarken Motoren und Getrieben mit kurzen Übersetzungen.

  • D

    Mir ist aufgefallen, dass die Beschleunigung - gerade im ersten Gang - etwas zu harsch ist. Da müsste eine Drehmomentlimitierung rein. Das ist eben noch ein Problem bei OMSI in Bezug auf drehmomentstarken Motoren und Getrieben mit kurzen Übersetzungen.


    Da hast Du Recht. Eigentlich ist der Motor insgesamt zu kraeftig, das ist aber auch schon bei der 240PS-Variante der Fall, mit der man voellig problemlos und ohne grosse Quaelerei in Roemerberg auf den Gletscher kommt. Der Turbofaktor kommt noch dazu, eigentlich muesste man mit geringerem Drehmoment anfangen und den Turbo den Rest machen lassen, wobei der Motor eigentlich eine recht leichmaessige Drehmomententwicklung hat. Der Bahnbus ist ja aber ohnehin noch eine grosse Baustelle mit vielen Kompromissen und unvollstaendig ist sie ja auch noch. Im Herbst und Winter habe ich dann bestimmt wieder mehr Zeit und Lust und ich hoffe auch die beiden grossen Zuarbeiter (ohne die die Mod nicht annaehernd waere wo sie jetzt ist) dann wieder motivieren zu koennen weiter zu machen

    :-)
  • There is template texture O305G_BS_DB86.bmp
    The panel will be matrix?
    Did you do version with matrix?


    The matrix version might or might not come at a later time. The Bahnbus mod wouldn't be complete without the two matrix versions (first version in 1985 with the standard size destination box at the front, no roofbox on the right (but matrix behind the 2nd window) and a wider number box at the back and 1986/87 the wider matrix at both the front and side. That would need to come with several other modifications like the matrix control panel (even with two different versions, as both AEG/TN ANNAX and Lawo matrix displays were used) above the driver, a new dashboard with a rev counter and the new switches from the O405, the removal of the roofbox both outside and inside, colour changes inside (roof vent surrounds, boxes above the doors, inner front and driver's cab in dark brown instead of grey) and so on. Don't assume anything to happen before the end of the year, if at all.

  • Hallo

    :)


    Erst einmal ein großes Lob für den O305G-Bahnbus-Mod. Er lässt sich super fahren und ist sowohl für Augen als auch Ohren ein Genuss. Besonders das Getriebe, welches beim Standart O305G Addon nach meinem Empfinden
    etwas spät schaltet , hat mich sehr überzeugt. Weiter so

    :thumbsup:

    :thumbsup:

    :thumbsup:


    Allerdings habe ich folgendes Problem:
    Die Fahrgäste wollen einfach nicht die vom Almex PDR A 1518 gedrucken Fahrscheine annehmen. Habe die Betriebsanleitung, die man ja auch schon in der Readme des O407 findet, auf den Punkt genau befolgt.
    Leider ohne Erfolg.

    :(


    Vielleicht kennt jemand hier das Problem und kann mir helfen.


    LG