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Oshkosh P-15 Crash Tender Replica

-----HISTORY-----

The Oshkosh P-15 is a real airport fire truck that was made around 1980 (dates are hard to find and verify). It held the title of the largest and heaviest fire truck ever made until the 2010s. It featured an 8X8 drive train, with dual Detroit Diesel engines connected to a 5 speed Allison transmission (automatic). On the top of the vehicle were 2 giant man-operated foam turrets, one on each end of the truck.

-----STORMWORKS RELEVANT INFO-----

The P-15 is fantastic for vehicle fires. It can travel quickly, and is decent at offroading. It has the ability to drag wreckage using any of the rope attachment points on board, and has a wide variety of tools for affecting repairs and recovery. The rooftop turrets can also be accompanied by handlines, which are available via the pump panels on either side of the truck.

As I'm going for a 1:1 recreation, this vehicle does not have a sufficient number of fire outfits, and has no drafting attachments. It assumes that the vehicle is being stored in a fire station where extra equipment including uniforms, adequate electrical connections, and water are being held.

If the truck needs water in the field, it CANNOT be taken directly from a body of water. It will need to be nursed via a tanker truck.

Starting:

1. Get in the drivers seat

2. Turn on the MASTER SWITCH

3. While holding W, turn the IGNITION

4. Release W as soon as the engines start

5. Wait for air pressure alarm to stop (or just wait for orange light to turn off if there is an emergency)

Driving:

1. While holding S, release the PARKING BRAKE

2. Use the GEAR SHIFTER to select FORWARD or REVERSE

3. Press W to drive, S to brake

Shutting Down:

1. Stop at desired location

2. Shift into NEUTRAL (between -0.2 and 0.2 on the SHIFTER)

3. Turn on the PARKING BRAKE

4. Turn off the MASTER SWITCH

-----INFERENCES AND EXPERIENCE-----

I tried as best I could to re-create the truck in Stormworks. Unfortunately, many of the smaller operational details about the truck (e.g. location and function of switches in the cab, if turrets movement was done by hand versus motors, etc) have been lost to history. Thankfully, using some very poor quality photos, and my IRL experience with Oshkosh crash trucks made before and after the P-15, I was able to piece together what operating such a monstrous truck would have been like. Below is a list of operations I inferred, as well as what they are based on. If they aren't in this list, then there are enough pictures of the part that their operation is easily evident:

-Oil pressure limits maximum speed - Most diesel trucks of the era had a wait time before the engine could be taken at full power. This was because the oil in the engine (as well as transmission) needed time before it had properly cycled. for a cold engine, this could take anywhere from 30 seconds, to a minute! On Oshkosh vehicles in particular, there is a safety interlock that physically limits the accelerator petal to a maximum of 1/2 throttle before the pressure builds.

-Air pressure limits braking power on startup, but not if the vehicle was run recently - This is common with all vehicles that use air to actuate brakes. Usually, if a vehicle hasn't been run in a while, the pressure in the air tanks is very low. When the vehicle is started, an air compressor mounted to the engine will bring the pneumatic system up to operating pressure (usually around 60-70psi). Once the engine is shut off, the air pressure will slowly bleed out over time through minor imperfections in the hose fittings. On all vehicles with this setup, a low-pressure alarm will sound when below 50psi (on vehicles made around the time of the P-15, a buzzer was used).

-Pump and Roll while the PTO is active - All modern airport fire trucks have this feature, and Oshkosh fire trucks have had the feature since the debut of the MB-5 im 1968. While the pumps are being driven by the vehicle's engine, it is possible for a specially designed transmission to output limited power to the wheels. This is mainly used in situations where a slight change in conditions can put a fire engine in danger, or to re-position.

-Position of switches/gauges in the cab - most/all Oshkosh fire trucks, past and present, put the master switch and ignition/heat switch to the right of the steering wheel. Oshkosh trucks of the era would also put all lighting switches together, and on the left of the steering wheel. The P-15 may have had so many instruments cluttering the dash, that they placed the lighting switches above the driver.

tags:
Aircraft fire, fire truck, crash tender, crash truck, oshkosh, P-15, firefighting, replica, 1:1, historic, Navy, United States, Air Force, fire engine, ARFF