Twotter Revived v2024.3.258 (still in beta)

For quite some time now, the behavior of the custom engine simulation upon engagement of the starter had the right shape, but it was way too slow. It took some time to find the flaw. Fixing it allowed me to retire one of the major "fudge factors" (aka "needle theater") that I had added because the behavior seen on reference videos wouldn't emerge naturally from the simulation. Now it does, and that makes me so happy.

I started some preliminary work on props, most of it cosmetical. As part of the groundwork, I replaced most of the sim's oil system. During shutdown, the oil pressure in the dome decays and springs pull the prop blades into their feathered position. Unsecured props are affected by wind using a bit of blade element theory, but note that this is just an approximation because of lack of references (breakaway stiction, inertia, rotational drag, the effect of oil viscosity, most is guesswork and subject to tuning based on feedback).

As part of the props groundwork, I enabled wind on the ground. I believe the change in behavior is negligible, but I'm open for feedback. Before, crosswind only affected the aircraft between 5 and 80 kts groundspeed, now these limits are gone. Turns out, that was a bad idea. Probably fixed in .259.

Last week's testing with the ski variant at NZWD made me look closer at sub-zero operations. Did I mention that I replaced the stock oil system? Starting a cold-soaked engine should be more fun now: the battery sags deeper, cranking against cold oil with low viscosity takes longer. "Pre-heat" buttons on the Systems tab let you blast hot air into the engines for ten minutes (press the button again to skip the wait) to get the oil up to temperature. The ground crew and the heater are invisible, use your imagination!

By now, this is probably what the modding community would call a "Total Overhaul". Almost every system in the aircraft has changed, many have been replaced and redesigned, and even some core sim systems had to go in favor of custom implementations.

This is a test version, please flag any issues you notice. I try to make sure the releases published on flightsim.to don't contain any blockers or stoppers that would keep you from flying, but bugs cannot be avoided and if you find one, please return it to its rightful owner.

If you run into issues or have questions, contact me here or on Discord: aurel#3010 (if you're active on Discord, we most likely share a few flightsim servers). If you know about the aircraft IRL or aircraft development in MSFS, I'm especially grateful for your input and suggestions.

Installation

NOTE: Because of previous drama around Aerosoft mods, this mod is distributed as an archive containing xdelta files and an install script. You will need an original, unmodded installation of the Twin Otter 1.1.1 (installed using Aerosoft One, the legacy Aerosoft installer, or by other means) so the installation process can READ the original files and WRITE the changed files to the mod folder. Your original files will not be touched.

Until the install script has been executed, the mod will be inactive.

Before you report an installation error, please consider reinstalling a fresh copy of the Aerosoft Twin Otter in the last release version (1.1.1) and trying with that folder. If the errors persist, please contact me so we can figure out why they happen. The installer should now work with all popular versions of 1.1.1.

The contents of the zip file:

• charliebravo-aircraftmod-twin-otter, this is all you need, you must unpack this to use the mod, the rest is optional
• charliebravo-soundmod-twin-otter-turbineduke, this is an optional sound mod, must own the Black Square Turbine Duke to use it
• z_aerosoft-twin-otter_propblur_mod, this is an optional mod that makes props blurry when you're close
• z_aerosoft-twin-otter_flat_cameras, this is an optional mod that levels out the cockpit camera views (the close pilot view and the three captain's instrument views), instead of having them tilted down at the panel
• historic_ndb_userpoints.csv, this file can be imported in Little Navmap to show historic (decommissioned) NDB beacons

You will still need to have the base model (ie. the aerosoft-aircraft-twin-otter folder) in your Community/ folder for the mod to work.

Step by step:

• UNPACK directly into community or wherever you keep your Community add-ons
• OPEN the folder charliebravo-aircraftmod-twin-otter
• optionally, if you're paranoid or they are actually after you: EXAMINE install.bat and install.ps1, overwrite the xdelta executable with a version you trust
• DOUBLE-CLICK install.bat or RUN install.ps1 in Powershell (install.bat is just a wrapper that executes the Powershell script)
• follow the prompts and SELECT an unmodified aerosoft-aircraft-twin-otter folder

In a perfect world, the changes are applied and you end up with a working mod and the lawyers have no leverage against me. I apologize for this, I can assure you that it has been even less fun to set this up. I contacted Aerosoft and Microsoft to get their blessing, but, so far, I didn't receive a response. It appears our Twotter is in some legal limbo: Aerosoft sold the rights to Microsoft, and now neither party appears to have any interest in the legacy product. xdelta helps me to stay on the safe side.

If you unpacked the soundmod:

• OPEN the folder charliebravo-soundmod-twin-otter
• DOUBLE-CLICK install.bat or RUN install.ps1 in Powershell
• follow the prompts and SELECT an your bksq-aircraft-turbineduke folder

Liveries

Legacy liveries for the Aerosoft model might work, if the loading order is carefully managed. You might have to rename folders to ensure the mod is loaded after base aircraft and liveries.

The Turbine Duke sound mod [NEW]

This version includes an optional, highly experimental sound mod that re-uses the Black Square Turbine Duke soundbank with kind permission by Black Square and Boris Audio Works.

This sound mod only works for owners of the Black Square Turbine Duke. To enable the sound mod, copy it to your Community/ folder and launch install.bat in the charliebravo-soundmod-twin-otter-turbineduke folder.

Because of the experimental nature of the mod, it is highly recommended you remove or disable it when flying the Turbine Duke. If you experience any sound issues in the Turbine Duke while this mod is installed (and they go away if you disable the mod), please contact me. We don't want to bother the nice people of Just Flight with problems created by the Twotter.

Resources:

• Read about what Twotter Revived can do for you in the Twotter Revived manual.
• Discuss the mod on the official MSFS forum.
• Find preview versions, release candidates and the mod's WASM source on Google Drive.

Twotter Revived is a community project. It is not endorsed or certified by De Havilland Aircraft of Canada. It is not approved by anyone in any way, shape, or form for training or any other real-world application. Any real-world references are provided for entertainment and educational simulation use only and may be incomplete, outdated, configuration-specific, or inaccurate.