Swedish Navy T21 class MTB

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Swedish Navy T21 class MTB
Swedish Navy T21 class MTB.jpg
Type Motor torpedo boat
Manufacturer Baglietto, CRDA, Kockums
Author(s) Anders Gidenstam
FDM JSBSim
--aircraft= MTB_20m
Status Alpha
 FDM Stars-2.png
 Systems Stars-1.png
 Cockpit Stars-0.png
 Model Stars-1.png
Development
 Website The website for the Swedish Navy T21 class MTB developments.
 Repository The development repository of the Swedish Navy T21 class MTB.
Download Download the Swedish Navy T21 class MTB aircraft package for the current stable release (2020.3).
License GPLv2+

The Swedish Navy T21 class motor torpedo boat were the second Swedish MTB class developed during the first years of WWII. The design was provided by the Italian companies Baglietto and CRDA but the 11 boats were manufactured at the Kockums shipyard in Sweden during 1942-43. They remained in service until the late 1950s, and some were retained for special purposes much longer. At least one remains today, T26, which has been restored to service condition, and as the hulls of some of others were sold on the civilian market after being decommissioned there might still be some other hulls around.

The 20 m long boats were powered by two 1500 hp Isotta Fraschini IF184 supercharged petrol engines giving a top speed of about 50 knots. The armament consisted of two 53 cm torpedoes and a 20 mm AA cannon.

Handling and controls

Engine controls

The MTB is equipped with two 1500 hp Isotta Fraschini IF184 main engines and two auxiliary Ford V8 engines for low speed manoeuvring. One main engine and one auxiliary engine is connected to each of the two propellers via gearboxes and clutches.

Main Engine Start

  1. Disengage the main engine clutches (Q). This action also selects the two main engines.
  2. Mixture rich (m).
  3. Magnetos BOTH (three times on }).
  4. Start the engines (s).
  5. Engage the main engine clutches (q). This action also selects the two main engines.

Auxiliary Engine Start

  1. Disengage the auxiliary engine clutches (E). This action also selects the two auxiliary engines.
  2. Mixture rich (m).
  3. Magnetos BOTH (three times on }).
  4. Start the engines (s).
  5. Engage the auxiliary engine clutches (e). This action also selects the two auxiliary engines.

Be careful to avoid over-speeding an engine with a disengaged clutch.

Installation and Dependencies

This "aircraft" depends on instruments and sounds from some other aircraft. Install a matching version of these too.

Known problems

  • The hydrodynamics planing model often reacts poorly to non-smooth water surfaces (in the terrain mesh, not waves) which is not that uncommon in FlightGear's terrain. Quickly reducing speed may help.
  • The hydrodynamics planing model requires a significantly increased FDM rate (the /sim/model-hz property) for good simulation results. On some systems this appears to have a considerable impact on the frame rate.