Flying the B 25

Taking off

Naturally this is my Flight Simulator and not the real thing, but sitting in the virtual cockpit of 34,000 pounds of an airplane looking out at 3,400 hp in two big noisy radials is a sight (and a sound) to behold. To make matters even more exciting, this is not the normal 7,000 foot runway one might be accustomed to, when attempting to take off with a bomber. This is an aircraft carrier, from which we try to take off. If you think this has never been accomplished before in a WWII bomber in the real world, remember the raid on Tokyo after the Pearl Harbor bombing, when on April 1942 the carrier Hornet brought sixteen B 25 bombers close enough to their target: the Japanese mainland.

All of them, fully loaded, took off successfully on April 18th 1942 from the storm-swept deck of the Hornet, 700 miles away from their targets. They could take off from the carrier’s deck, but they couldn’t land back on it anymore, so their way back meant they had to find their way to a yet unknown small landing site at night somewhere in China. This mission was called the Doolittle Run after Army Lt. Col. Jimmy Doolittle, who was assigned, or let us better say, assigned himself to lead the raid.

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Luckily we don’t have to think in our flightsim today about storm swept seas and how to make it home after we have crash landed our plane in a remote place somewhere in Eastern China. We also don’t have to think about constant speed props, boost pumps, oil coolers or feathering systems to name just a few. For the pilots it is quite a challenge to get into their seats, once they have entered the flight deck through a hinged hatch in the belly of the plane. The cabin is pretty low and due to the limited width of the fuselage, both seats are fairly close together. So getting into one of them one is more or less forced to bow forward and walk on the knobs and levers that cover the floor space between them or try to make a huge step. But once seated, one realizes that the instrument panel is in some ways simpler than the one in a modern light twin, although a few of the instruments such as the altimeter and turn indicator are placed rather oddly fairly low out of the pilot’s direct view.

 

The switches for starting, fuel management and feathering are on the panel just in front of the throttles and the props are feathered by pressing the large red buttons on this panel. The side panels of the cockpit are covered with emergency system controls.

Now we “just” have to get this old bird from the carrier up into the air. The boost pumps are on and my right hand is wrapped around the two throttles. I just follow the take-off procedures given to the Doolittle pilots in April 1942: full flaps, you slowly apply full power in order not to cause the prop governors to surge and you stay with your body weight on the brakes until the monster torque is almost tearing your plane apart. Then you release the brakes and as soon as the plane starts to roll, you pull the wheel all the way back and start to pray.

The two R-2600 roar along the carrier’s short 250 meters (825 feet) runway and once we are off the ship’s deck, the fully loaded bomber takes a dive before it generates enough lift to slowly start to climb. It seems to be an eternity and doing that in real life must have been quite a hair-raising experience. We level off in order to allow the plane to gain CSE flying speed of 120 knots.

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Its origins

The North American’s B-25 Mitchell came to life upon a 1937 request by the US Army Air Corps for a twin-engine bomber to replace existing smaller single engine ones. Unfortunately the first prototype NA-40B with two 1,600 hp Wright Cyclone R-2600 engines crashed in April 1939, so the Army opted for the Douglas A-20 instead. But a further Army request from March 1939 gave North American Aviation another opportunity and they built the NA-62, a larger version with a slightly wider fuselage and side-by-side seating for the pilot and his co. Initially the USAAC ordered 184 planes, designated B-25. Its naval variant was named PBJ-1. The first such plane, the B-25A flew on February 25th 1941. From December 1941 to May 1943 another 1,619 bombers of the type B-25B were delivered, the first large scale production version of the B-25. The largest production run of any B-25 version was the B-25J, of which 4,318 were built between December 1943 and August 1945. All in all some 9,984 planes were produced. The very first B-25 produced was kept by NAA and used as an executive plane, fitted with five large passenger seats, a bar and other conveniences. It was called the “Whiskey Express” and kept by the company until it was lost in 1945 in a belly landing.

The B-25 had two 1,700hp Wright R-2600-13 double cyclone fourteen-cylinder air-cooled radials that gave it a maximum speed of 275mph at 15,000 feet. Their empty weight was 21,100lbs, their maximum weight 34,000lbs, but by utilizing their maximum overload capacity, the weight could go up to an enormous 41,800lbs.

For the “Doolittle raid”, the fuselage armor was removed and the lower turret was replaced by a 190 liter (50 gallons) fuel tank. Other fuel tanks were added so that at the end the B-25B’s fuel capacity was enlarged from 2,625 liters to 4,320 liters (694 gallons to 1,140 gallons). As an interesting side note, when Doolittle took off from the carrier’s deck, his plane was positioned ahead of the others, which meant he had with just 142 meters (467 feet) the shortest possible real estate to take off from. The Hornet had steamed into the wind and gale force winds of 75 km/h (40 knots) made the take off easier. So easy in fact that he was able to take off with some 30 meters (100 feet) to spare.

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Source: United States Navy Naval History and Heritage Command

Flying the Mitchell

Once up in the air one realizes of course that our Saitek stick is nothing compared to the real world. But this beautiful FS9 MAAM B-25, which I bought in 2005 and now fly in FSX, still does a pretty good job for the average simmer like me. I am aware that there is an upgraded version for FSX available from MAAM, but as it is still based on the original FS9 version, I wait until a genuine FSX version will one day be available from them. The real world aircraft demands both your hands and plenty of muscles to pull the wheel back and keep the nose pointing upwards. But now we have settled into our flight routine, the flaps are up, booster pumps off and we have reduced power for a continuous climbing speed of 140 knots. The plane climbs at an average 1,100 feet per minute, above 10,000 feet the pilot training manual asks to switch booster pumps back on. It also reminds the pilot that in order to reduce power, one has to reduce manifold pressure first before rpms are reduced, otherwise one will get a jump in manifold pressure, which causes pressures in the impeller and cylinder heads to rise and leads to detonations. The B-25s service ceiling is 24,000 feet and it has a range of 1,303 nautical miles with 3,000lbs of bombs. But today we don’t want to fly that high, don’t want to go that far and for sure don’t plan to drop bombs on any target.

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Our course will take us some 250 nautical miles south from the carrier’s position to Orcas Island, the largest of the San Juan Islands in the northwestern corner of the state of Washington. After having reached 15,000 feet we have enough altitude to try to test the plane for its behavior. First I make a turn to the left and the wings answer immediately by rolling into a left bank. As expected the nose starts to fall and we lose altitude. With a 30 degree bank to the left I have to pull the wheel all the way back to keep the nose from falling further. What is easy to correct in our simmer’s life is quite a chore with the Mitchell in real life, as the control pressures are so heavy.

 

Turning off one engine is another nice exercise to keep your heart racing and your blood pressure unhealthily high. After the propeller comes to a stop, the blades edge into the wind, a 50 and even 60 degree banking turn into the dead engine is possible. You then fiddle with some trim wheels and the plane keeps on flying as if nothing has happened. No wonder it was reported that the B-25 was a safe and forgiving aircraft to fly.

In this respect the plane reacts in the sim almost the same way as in real life, except of course that the sim will not show you what it means to “fiddle with some trim wheels”. The real plane will demonstrate pretty dramatically, which will be your idle foot. Until the plane has been properly trimmed, you practically stand on the rudder and try to push it all the way down, while you press your shoulder forcefully against the seat to get some balance into your body and more weight onto your trembling leg. At the same time your right hand frantically cranks in some rudder trim, located at the bottom of the control console. Once this has been accomplished, you can start to breathe normally again, because now the plane does indeed fly like an angel. Don’t try this if you are anything shorter than 6 feet and anything lighter than 80 kg (175lbs), because your leg will not be long enough and you not strong enough to fight the rudder all the way down.

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Still having sufficient altitude and running again on both engines, I decide to bring the Mitchell into a stall to see how such a large plane would behave. I reduce power and bring the nose up. Even at our weight of some 34,000lbs, the plane acts rather mildly in the sim. The stall does not occur until we are down to around 85 knots. Then the nose starts to shake, but the plane does not start diving to the ground, tail first, as one might expect from such a heavy aircraft. Instead the nose drops through the horizon and rolls slightly to the left. I keep the nose down and slowly add power and we have flying speed again in around 1,800 feet, having lost no more than 2,400 feet in altitude after I have leveled off the plane again. From what I have read about the Mitchell from actual flying reports, this is a similar behavior in real life, with the only difference of course that the sheer physical efforts involved are momentous. In the stall the plane’s controls have lost some of their effectiveness, so you need plenty of arm muscles (and adrenalin) to get the nose up again.

Landing the old-timer

The real fun part starts of course when we get close to Orcas Island and want to land the plane. Orcas Island is surely not the ideal airfield for a B-25 novice pilot, as it has a relatively short (884 meters or 2,900 feet) and fairly narrow (18 meters or 60 feet) runway, but we will give it a try to test our skills. In the simulator I have brought the weight of the plane down to 21,000lbs and will go for a straight-in. My approach will be long, with plenty of power and the nose slightly lowered. I fly the downwind approach at 120 knots, lower the gear and keep the props at 2,200 rpm. It will stay at that rpm level until I touch down on the tarmac.

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On base I realize that I need more power to maintain approach height and speed, while cranking in more trim every few seconds. As soon as I turn short final, I go for full flaps, slightly reduce the power until we reach 110 knots on the gauge and keep the nose on the point. As I approach I flare off, reduce power and speed in order to land the plane gently on the main gear. That was fun!

The reality is again slightly different, as on short final you really need to pull the wheel all the way back in order to avoid to touch down on all three wheels at the same time, putting too much strain on the nose gear. So you land in fact with the nose in a steep angle, hiding the runway from the pilots view.

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After you have put down the nose gently, the plane rolls out in a straight line, but you have to be very gentle on the double disc brakes in order not to block them and ruin your (or the plane’s owner) day. They are highly sensitive and you better barely touch the top of the rudder pedals without the nose taking a visible dive. This makes not only braking, but also taxiing the plane “an affair to remember”.

Sources: The North American B-25 Mitchell, by Stephen Sherman

The North American B-25 Mitchell, by Greg Goebel

North American B-25 Mitchell, The ultimate look, by William Wolf

The B-25 for FS2004 and FSX can be found at MAAM’s website:

http://www.maam.org/maam_sim.htm

by Bernd Schulzkoehling

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