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| Thanks to all who added to my comments. John's below jogged me to add to the perspective..... The "back side of the curve" is a significant and large sped range in a IV as compared to most GA aircraft where it is a narrow band very near stall...... lot's more room for an untrained pilot to get into trouble.
Jack Morgan On Jun 1, 2013, at 6:00 AM, Lancair Mailing List wrote: Subject: Re: [LML] IV P flying
Date: May 31, 2013 6:24:54 PM EDT
Jack,
Well, I agree sort of with your conclusions but not necessarily your explanation. I think you are referring to what we used to call the back side of the power curve centuries ago in the USN. What is happening when you get slow and is more critical with high wing loading is that the L/D ratio is decaying and perhaps in that scenario some would not recognize the need to compensate and correct by lowering the nose and adding power.
One of the best lessons I ever learned and I think this came from carrier landing instruction and practice is that on approach and during landings you control airspeed with attitude (stick) and you control rate of descent with power. It's probably not intuitive at first for most but once you get it in your head it makes landing phase so much more controllable and sensible (ask Grayhawk about this term) that your landings will forever be more safely accomplished no matter what type of airplane you happen to be operating at the moment.
John Barrett
31VP
Sent from my iPad
On May 31, 2013, at 10:26 AM, Jack Morgan <jmorgan1023@comcast.net> wrote:
This will probably stir some controversy but I think it is important to stay safer in a IV.
There is recent discussion about AOA and vortex generators with the IV and I will leave that to owners preferences. I believe the real issue with the IV is the rapidly increasing sink rate below 95 knots. Like all really high performance aircraft, slowing results in very significant power off sink rates well above stall. The high wing loading inherent in these aircraft is the reason for the speed/efficiency and the trade off is the sink. For pilots not used to this class of aircraft when slow, pulling back hoping to climb results in a very unfamiliar rapid loss of speed with no change in descent rate. Unless back pressure is relaxed quickly the remaining speed above stall dissipates very quickly. Once the departure comes, adding power just aggravates the spin.
The main thought is to stay above 100 knots so as to stay high enough on the speed curve to give a normal feel/result to the controls. The recommended 120 knots in the pattern and 100 knots over the fence meets this demand. If you have an AOA in your IV and can get it to blow the whistle at 95 knots I suggest you do so.
Those who would add vortex generators or an AOA so they can purposely operate the IV near stall are venturing into a potentially very dark place with little to be gained. Most aircraft in this class are turbines/jets and the operating manuals don't allow stalls or very slow flight.
Jack Morgan
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