Yes, it's true that there is a difference in the flight profile after liftoff between, for example, the B-25 and the DC-3. But for a very good reason! Again, let me clearly say up front that these two airplanes are used here only as an example, not as specific ones or the only ones. Another aside on this subject, the matter that I'm talking about in the paragraphs below applied in my experience to twin engine airplanes. When they had an engine fail, it represented a fifty-percent loss of power.
This is a severe handicap by anyone's standards. In the case of the four-engined airplanes, they might not have required the extreme attention given to the V2 attitude with the twins. But, even with those, Paul Soderlind at Northwest developed and prescribed a precise attitude to be rotated to, it also delivered the most "bang for the buck" out of a sometimes rather reluctant airframe on takeoff.
In the B-25 you'll need to read Warbird Notes #2 (Decelerating Approach) to get a feel for what we are discussing here. Suffice it to say, with the B-25 or others of its ilk, we have an overriding need to obtain airspeed just as quickly as possible because, if one engine should fail below SSES (Safe Single Engine Speed) you'd have no choice but to quickly reduce the power on the remaining engine in order to avoid the resulting uncontrollable roll. So in this case airspeed is obviously of the essence! Conversely, consider the case of the DC-3, an airplane possessing a much lower VMC and having a V2 airspeed. Yes, I know the DC-3 was and is operated under a special waiver of the regulations but the fact remains that the manuals define a V2 for it. Incidentally, the B-25, with its military design background, never did have a V2 airspeed defined, listed, prescribed, written or whatever. Seems to me that anyone trying to tell you differently is spreading some BS or, to put the best face on it, just perpetuating one of those Old Wives' Tales. Might be informative to both of you if you'd say, "Could you show me where that is in the book, please?" In the case
of the DC-3, once you've attained sufficient airspeed to control it and climb on one engine, you are far better off to obtain as much altitude as possible before (or) if, an engine fails.
Flight instructors (in that part of the trade) know the attitude that will accomplish this for you as the "V2 attitude". So, to make life as simple as possible for yourself after liftoff, rotate the aircraft to a V2 attitude. Until you can do this in your sleep on a dark night with a bad artificial horizon, this attitude is roughly the same as the DC-3 at rest on the ramp in a three-point attitude. After placing the aircraft in this attitude and retracting the landing gear, allow the aircraft to accelerate to V2+10. Maintain this V2 attitude and reduce to METO
power. Continue the climb in this attitude (and V2 plus 10) until reaching the obstruction clearance altitude (OCA). We always used 300' above field elevation on the airline; others may have some specific circumstance that required the use of a higher OCA. For now and for this operation, however, lets use 300'. After attaining this altitude, lower the nose slightly and allow the aircraft to accelerate to climb speed. (For the DC-3, that's 105 knots) Then you may reduce to CLIMB power.
Due to what some might call serendipity, if you're maintaining this attitude and V2+10 on two engines, this is the same attitude that will pretty much result in a decrease to V2 if you suffer an engine loss and you reapply MAX power. Actually, it really isn't serendipity, it's the result of a lot of experimentation and applied thought by some pretty experienced aviators of the past. They didn't have a plethora of aircraft performance to work with; accordingly they were masters at obtaining the best performance out of a marginally performing airplane. And I think they were also masters at transferring this knowledge to
those of us that came along later. Another thing here, if you're holding a V2 attitude and notice that you've slightly overshot the V2+10, don't abruptly raise the nose in an attempt to reacquire (chase) the airspeed! Most likely you'll again overshoot in the opposite direction and just end up in a series of pitch changes. Conversely, if you notice a momentary loss of the V2+10 airspeed, don't abruptly lower the nose and chase it, just attempt to influence it slightly in the correct direction. These aircraft attitudes, to some degree, are approximations but will be of inestimable help to you in avoiding the frantic need to hastily adjust the pitch while you're also trying to deal with all the other distractions of an engine loss close to the ground.
If (or maybe I should say when) an engine fails after liftoff, you'll be awfully glad you religiously used this habit and have the altitude already in your hip pocket. If you'd flattened your climb (a la the military) obviously you'd have more speed. But, after watching this hundreds of times, you'd be unsuccessful in converting this excess airspeed into an usable altitude all the while trying to also get the offending engine shutdown and feathered.
So, that's why the difference in the way certain airplanes are handled. Unfortunately, they're not all the same. Some were designed for the military with a really high VMC, they were obviously expendable! And, for that matter, so was their crew and occupants no matter how fervently we might wish to not admit that fact. Other airplanes might benefit from the more controllable characteristics and benign aeronautical mannerisms of a transport design. Let me digress briefly to the matter of the B-29, an airplane plagued by engine heating problems from day one. In this particular case we fly it the same way we do in the B-25. I.e., hold it flat and get the maximum airspeed as quickly as possible because of its overriding cooling problems. This cooling problem isn't evident on the DC-3 or the Convair, etc., therefore the differences. All different, it looks to me like a case of "you pays your money and you takes your choice!" All have valid reasons for being, it's up to you to provide the human intelligence to manage the machine to obtain those results that you both want and need.
R. Sohn © 1999
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