WEP/MIL

I got looking into WEP for the Spitfire.

Apparently there is a curve in the throttle lever channel to give the Pilot an indication when the aircraft is in WEP. I stood up with my TrackIR on and zoomed into the channel in DCS.

Sure enough the fine Devs haver modelled it faithfully. Very nice!

Sorry...And WEP is? Does the switch operate?

War Emergency Power. Anything above +12lb Boost, Max +18lb. 3000 RPM, required at a minimum. 5 Minute limit and make sure your going >220 IAS to keep the temps under control.

"Get Outta Dodge" mode, meant for hasty retreat rather than added oomph in a dogfight.

The switch is simply the battery power, for energising instruments and lighting etc. It operates on a catch connected to the throttle so once the throttle is advanced it throws the switch automatically, hence why you work the thottle lever during start-up.

Since we as sim Pilots cannot actually feel the detent, I made it an idiot light. Here is my take on WEP in the Spit and my workaround. It seems to be modeled pretty accurately and I was wrong in saying the stock curve was off. I had changed the curve before I changed it again for this.

5 minutes:

https://youtu.be/4uJ6eRH_T80

Thanks for the explanation. I thought it was something connected to the throttle that brought your panel alive, and now I know what. Yes, I have heard of WEP - which in some WW2 aircraft was actually a fuse wire barrier which physically prevented the throttle movement until it was actually broken by the action of the throttle going forward. Maintenance had to check an engine when this wire was broken.

Why not make use of the afterburner detent feature in the warthog throttle too. This would give the tactile feedback required and could also be used in VR where the lights cannot be seen.

Why not make use of the afterburner detent feature in the warthog throttle too. This would give the tactile feedback required and could also be used in VR where the lights cannot be seen.

It was considered however the WEP in the Spitfire covers a range of sweep and is not simply off and on.

At a given altitude one can have a range from 12 to perhaps 18 psi boost or higher while in WEP. Note the length of the slot in the throttle channel after the curve.

I haven't run across anything as of yet indicating that WEP in the Spitfire referred to water injection or anything that could be turned on or off by the switch at the ends of the throttle travel.

It seems that it just referred to throttle position anytime it was moved past AND beyond a certain point which no doubt had some other things happen further down in the engine.

I use the switches at the idle end of the throttle and the prop pitch rpm lever to operate my mag 1 and mag 2 on the Spitfire.

Thanks for the explanation. I thought it was something connected to the throttle that brought your panel alive, and now I know what. Yes, I have heard of WEP - which in some WW2 aircraft was actually a fuse wire barrier which physically prevented the throttle movement until it was actually broken by the action of the throttle going forward. Maintenance had to check an engine when this wire was broken.

Indeed the P-51 has been stated to have had the wire. The Spitfire has the curve in the channel and the Pilot was to report hours of use in WEP. I.E. Past the curve.

Some models of Mustang also had water injection which was metered according to Manifold pressure (boost). It was turned on and off with a switch and had a light to indicate it was on.

Water injection, I would consider part of the WEP as well if equipped.

Water injection used to be big back when I was drag racing. It was said to cool the intake charge making it denser allowing more air accompanied by more fuel when on to give a bigger boom inside the cylinders.

I am not sure it would add oxygen to the mix like Nitrous Oxide does.

Alcohol would keep it from freezing and I would think help keep detonation down by raising the octane rating a bit and slowing the burn.

Detonation, pinging, knocking is actually the tops of the piston flexing in response to too violent of an explosion in the cylinders instead of a nice burn. They cannot stand this for long.

It will also pound crankshaft main and connecting rod bearings big time.

Any time spent in WEP is begging for that kind of trouble with the increased compression pressures.

In the old days of drag racing some folks had a high gear switch which retarded the timing in high gear which would help a bit.

Today's engines adjust themselves to avert disaster pretty quick.

It is so hard to find information about the actual workings of the WWII aircraft.

cool link with a bit of info.

https://en.wikipedia.org/wiki/War_emergency_power#WEP_in_World_War_II_aircraft

The accuracy of any information I find on the internet of course could be false as we know.

I take your point that WEP is a variable setting.

You have given me another idea which may be more practical for me in VR. I have made another plastic detent stop slightly modified so the throttles can be pushed through and do not have to be lifted (like the old Cougar throttle, just a bit more resistance at that spot).

By adjusting the curves I have set this point at Max Continuous (2650rpm +7psi). It is a bit fiddly to maintain the correct response at low settings also, but I am getting there.

This makes it a lot easier to set max continuous power and be kind to the engine. :)

The point is the slot. The Boost will vary with altitude.

It is simply an indicator I believe. All it is, is a curve in the slot. The throttle and every function would work exactly the same without the slot. It is there for Pilot feel. Since there is more travel after the end of the curve, I would say it is variable. The butterfly in the carb simply opens wider. More air, more fuel, more load on the moving parts, more heat.

Add low airspeed, rad flap closed, high rpm and quickly *BOOM* You're a glider.

Depending on altitude one can easily go from 12 psi to 18 psi all being in the WEP section of the slot and the Pilot would be expected to log that time in WEP.

I like your idea of making it a physical thing one can feel.

That rpm and boost will change drastically depending on altitude.

Certainly, I found at the altitude the supercharger kicks into second gear or just before, 7psi boost is maximum before you're fully in the forward WEP area of the slot. 16,545 ft. in my latest mission.

It will still climb up through the altitude where second gear kicks in and at that precise altitude in Full Speed Supercharger it can give you near 12 psi boost without WEP.

That boost drops drastically as one climbs from there.

At a low altitude one can go far beyond 9 psi boost without having to move the throttle that far.

Try going up and down from 15,000 to 20,000 and watch your boost, oil and coolant Temperature, Oil pressure and RPM gauges while paying close attention to the slot.

Try to stay out of the slot. *WEP*

War EMERGENCY Power.

There is no reason to work the engine that hard unless you're in a dogfight or dire straights.

Staying out of the slot is not the only consideration for maximum engine survival.

I spend most of my time at 9 psi with 2840 RPM while climbing to the altitude where it would force me to go into WEP which I won't do and so boost pressure will drop off more and more until the supercharger switches gears where one has to throttle back to get back down to around 9.

Fly over some mountains.

My knee board reference someone else made (Thank you Sir): pic attached.