DA42 vortex generators

Any DA42 related topics.

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Colin
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Re: DA42 vortex generators

Post by Colin »

That is some beautifully recorded and presented data saving me a few thousand dollars. Thanks!
Colin Summers, PP Multi-Engine IFR, ~3,000hrs
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N972RD DA42 G1000 2.0 s/n 42.AC100 (sold!)
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ememic99
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Re: DA42 vortex generators

Post by ememic99 »

Thanks for sharing data but I still miss to see benefits. On the other side, people spend thousands of dollars to get few knots of cruising speed. For example such gain you get by changing standard props to scimitar.
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TwinStarScott
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Re: DA42 vortex generators

Post by TwinStarScott »

Here's my experience with vortex generators (VG's) since installing them on my TwinStar earlier this year. On the initial test flight one could literally feel the added buoyancy with the wings generating more lift. As a result, landings did take some getting used to because using the old approach speed the airplane would now float and float, and sometimes float some more. Also, I've found when flaring just slightly high, adding a touch of power helps grease the landing. With VG’s, the same amount of minimal power caused the airplane to balloon way up. So the amount of power added had to be adjusted downwards to an almost microscopic amount.

Here are some further points:

● with full flaps and the gear down, the airplane now stalls at 49 knots (which is amazingly low for a light twin)

● with slower approach speeds on short final, much less braking is required after touchdown

● added confidence to land at shorter runways, either planned or in the event of an emergency (more on that later*)

● increased rate of climb – MicroVG's claims 150 FPM and in my experience it's more like 200 to 250 FPM . And depending on where one is based, this can be a big deal – it certainly is for me when clearing trees at a heavily wooded private runway, as it helps to shorten the dangerous time window when the airplane is at maximum power and close to the ground on takeoff or on the infrequent go-around.

● as for any decrease in cruise speed, the G1000 didn't seem to change much, if any. On long cross country trips and above 10,000 feet, the TAS would consistently read 159 knots without VG's. After installation, it was almost always the same. Sometimes it might read 157 or 158 under the similar flight conditions. No big deal in my book.

If any TwinStar owner does decide to install VG's, plan on plenty of practice approaches at an airport with a long runway until you adjust to an approach speed that doesn't result in a float.

My overall impression is this modification is well worth the investment given the increased safety margins the VG's provide. If you believe the sales literature on this product, VG's have saved many lives over the years. And by fixating strictly on TAS it's overlooking the fact that every flight obviously requires a safe takeoff and landing and this is where VG's make these two most critical phases of flight safer.

* in the interest of full disclosure, I routinely fly into the Anacortes airport because they always have attractive prices on JetA ($3.37 per gallon currently). Despite a sloping surface, it's not an overly difficult 3,000 ft strip. Yet having so many landings there in the TwinStar, the difference between before and after VG's is significant - with decreased braking and the amount of used runway. Ironically this is the same airport where Micro AeroDynamics is based and over the years I have infrequently met both Charles, Anni and their friendly, helpful staff. They have a clean, well organized and efficiently run operation. And from my limited perspective this very small company is truly dedicated to aviation safety. Call me biased if you like.
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