• Head-To-Head Feature XII: Dash 8 Versus EMB-170

    Head-To-Head Feature XII: Dash 8 Versus EMB-170

    By Ron Blehm

    I've heard it said that some of the modern turboprops (such as the Dash-8 series) are so fast that airlines may choose them over RJs like the CRJs or Ejets. In our last feature I set about to test that theory with some flights in the Philippines. Sure enough, although slower than the E170 or CRJ700 when the fuel-burn/efficiency scores are added in, the Dash-8 came out on top.

    Well, that may only be Dreamwings idea of things although a past feature showed the B-17 to be more efficient than the B-52 even on an hours-long flight. For one last fling with this thought I figured I'd go Head-to-Head with the two Dreamwings models from last time (both of these beat out the default CRJ for speed and fuel burn).

    If you have been following this series you'll know the drill. I took sixty-five, 210 pound passenger/bag combinations and loaded that into the Q400. Then I added another 4,500 pounds of cargo. Then I topped off the tanks (about 73% capacity I think) with 9,100 pounds of fuel. That was darn-near the MTOW. I marked the time at 9 AM in Chicago, and pushed back from the gate; Start-up, taxi and departure from runway 13C at Midway Airport headed to Boston Logan.

    Maintaining 250 knots below 10,000 feet and then climbing at 85% power I reached 25,000-foot cruise at 40 miles before the JXN VOR. Waypoints were DKK, ITH and EEN VORs along the way. Ground speed was 365 knots. TOD was 49 miles before EEN. I crossed over the SKR NDB and intercepted the ILS for 15R at 6 miles DME.

                       

    I landed smoothly and taxied to the gate with shut down at 12:26.

    Then I moved to the Dreamwings EMB-170 and loaded in the same passenger/bag combinations plus the 4,500 pounds and about 80% fuel which was 17,692 pounds. For both aircraft then, this put take-off weight within 200 pounds or so of the MTOW! The Ejet can haul more but it's also heavier so there is a weight versus load trade-off there. I marked the time at 9 AM in Chicago, and pushed back from the gate; start-up, taxi and departure from runway 13C at Midway Airport headed to Boston Logan.

    Maintaining 250 knots below 10,000 feet and then climbing at 75% N1 I reached 25,000-foot cruise at 85 miles before the JXN VOR. Waypoints were DKK, ITH and EEN VORs along the way. Ground speed was 415 knots. TOD was 49 miles before EEN. Maintaining the 250 knot speed limit, I crossed over the SKR NDB and intercepted the ILS for 15R at 6 miles DME.

                       

    I landed smoothly and taxied to the gate with shut down at 12:16.

    So, the jet is faster by 10 minutes; no shock there. But as you well know, we need to factor in fuel burn. What I've been doing is adding two seconds per pound of fuel burned. The Dash-8 (according to Dreamwings) burned 5,231 pounds versus the E170 which burned 7,242 pounds (remember both aircraft were near their respective MTOW for this flight). Two thousand pounds is four-thousand seconds which is over an hour which pretty much washes away the ten-minute time advantage. They say "time is money" and even if we factor just half-a-second per pound the Q400 still wins and I'm sure that gas is more expensive than that!

    Ron Blehm
    [email protected]

    Tags: head-to-head

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