---------------------------------------------------------- Lightning-List Digest Archive --- Total Messages Posted Tue 10/21/08: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:38 AM - Re: Blanking Effect (Kayberg@AOL.COM) 2. 05:58 AM - Re: Blanking Effect (EAFerguson@aol.com) 3. 06:05 AM - Re: Blanking Effect (N1BZRich@AOL.COM) 4. 10:36 AM - Re: Blanking Effect (Kayberg@AOL.COM) ________________________________ Message 1 _____________________________________ Time: 04:38:24 AM PST US From: Kayberg@AOL.COM Subject: Re: Lightning-List: Blanking Effect Buz, I was suggesting a flaps-up takeoff only. It is easy to rig the plane so flaps and ailerons are all even. If you take off in that configuration, then you should not have any serious wing drops. Of course you would then test the flaps while exploring slowflight and perhaps approaches to stalls. You can make rigging adjustments later. It was the comment of some that they "ran out of elevator" on landing and blamed "blanking". I dont know if that is really the story or not. There are several possible causes including poor piloting. Sometimes there is a point in landing a Lightning where you have full back stick, full flaps, nose up position and you simply must wait for the touchdown. The nose doesn't pitch down, which rules out the "blanking". But you can have a sense that you have no control for a millisecond. Doug In a message dated 10/20/2008 8:06:18 P.M. Eastern Daylight Time, N1BZRich@aol.com writes: Doug, I generally agree with your "short answer" comment that the airplane is not going fast enough to get pitch authority. However, I am not familiar with "blanking" being suggested (and debated) that had to do with full flaps and limited elevator just before a stall landing. What are we talking about here? The basic design of the Lightning (elevator not high above the thrust line and flaps limited to 40 degrees full down) will prevent any blanking of the elevator certainly up to and at the stall angle of attack. In fact with flaps down, you are much further from even getting close to this situation than you are with flaps up. Remember what the Lightning does as you lower flaps - the nose goes down. And I have not idea what is meant by "limited elevators". I also don't totally agree that the first flight should be with no flaps at all. For the first flight in a Lightning, during the "near stall investigation" portion, I recommend you accomplish the yaw, roll, pitch and trim investigation between speeds of 85 to 65 mph, clean, then at 10 degree flaps, then at 20 degrees, and then at 30 degrees. Some people even take the bottom end of the speed down to 60 mph and that would work well with the new tips and still keep you above the predicted clean stall speed. Of course if any of these step by step objectives indicate any problems, stop at that point and make that first landing at the previous setting. This is kind of what is recommended in the FAA Advisory Circular 90-89 (I hope I am remembering that number right.) Buz ________________________________ Message 2 _____________________________________ Time: 05:58:18 AM PST US From: EAFerguson@aol.com Subject: Re: Lightning-List: Blanking Effect In a message dated 10/20/2008 8:37:58 P.M. Eastern Daylight Time, ryan@greenlandings.com writes: Walt, If I am not mistaken your aircraft is at Greg Hobbs airport. Walt. Having visited Greg's place (~1000' runway with fences at both ends) I would expect the first test flight to be made with at least 10 deg flaps. If the runway is rough, as it was when I was there, any perceived loss on elevator authority would call for an immediate abort. One suggestion would be to truck it over to a local paved and longer runway like Marana. Not simple or cheap, but it would provide a better setting for testing. With 250+ hours and about that many take offs and landings in my Lightning, I've never had any indication of blanking. I do most TOs no flap, but have been through the full flap deployment range to test. I frequently side slip to lose alt on landing, but don't think I've ever had full rudder in doing it. Never a hint of loss of elevator authority. One possibility that has not been mentioned is to check the horizontal stab incidence. If incorrect by even a small amount, this could be the problem. Finally, the trim system makes a difference. You will have more elevator authority with the servo trim than with the bungee. That comment will probably start a new discussion thread, but trust me. We changed to the new system on N17EF at 200+/- hours and there is a definite difference. "We" was mostly Nick, I was there to watch. Since your's is a newly completed ship, it probably has the new trim system, but I haven't seen that stated in the e-mails. Hope these comments help. Earl Ferguson **************New MapQuest Local shows what's happening at your destination. Dining, Movies, Events, News & more. Try it out (http://local.mapquest.com/?ncid=emlcntnew00000002) ________________________________ Message 3 _____________________________________ Time: 06:05:41 AM PST US From: N1BZRich@AOL.COM Subject: Re: Lightning-List: Blanking Effect In a message dated 10/21/2008 7:39:09 A.M. Eastern Daylight Time, Kayberg@AOL.COM writes: Sometimes there is a point in landing a Lightning where you have full back stick, full flaps, nose up position and you simply must wait for the touchdown. The nose doesn't pitch down, which rules out the "blanking". But you can have a sense that you have no control for a millisecond. Doug, Right on. Just substitute the word Lightning for airplane and it sounds like the perfect set up for a full stall landing. The millisecond or whatever time delay will depend on just how high you flared above the runway. Hopefully six inches or so. Buz **************New MapQuest Local shows what's happening at your destination. Dining, Movies, Events, News & more. Try it out (http://local.mapquest.com/?ncid=emlcntnew00000002) ________________________________ Message 4 _____________________________________ Time: 10:36:07 AM PST US From: Kayberg@AOL.COM Subject: Re: Lightning-List: Blanking Effect Few things in life compare to that feeling when you realize you are in full stall about 10 feet above a runway....when you thought it was 10 inches! Thankfully a Lightning will float in better than many others if you just wait. Of course power will help, but that feeling is priceless! Doug In a message dated 10/21/2008 9:06:05 A.M. Eastern Daylight Time, N1BZRich@AOL.COM writes: In a message dated 10/21/2008 7:39:09 A.M. Eastern Daylight Time, Kayberg@AOL.COM writes: Sometimes there is a point in landing a Lightning where you have full back stick, full flaps, nose up position and you simply must wait for the touchdown. The nose doesn't pitch down, which rules out the "blanking". But you can have a sense that you have no control for a millisecond. Doug, Right on. Just substitute the word Lightning for airplane and it sounds like the perfect set up for a full stall landing. The millisecond or whatever time delay will depend on just how high you flared above the runway. Hopefully six inches or so. 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