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06-04-2016, 03:45 PM
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Join Date: Nov 2005
Location: AUSTRALIA
Posts: 749
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Two other possible contributing issues.
With trees around some of the headwind component may have been lost near the ground.
Airspeed may have dropped below your desired 60 kts as the natural reaction is to slightly pull back on the stick when the ground is rushing up. Not easy to notice this as the eyes are on the landing strip rather than the ASI when near the ground - good argument for an AoA with audio.
Fin
9A
Last edited by Finley Atherton : 06-04-2016 at 03:48 PM.
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06-04-2016, 05:02 PM
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Join Date: Aug 2009
Location: Newport, RI
Posts: 705
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Practice
I landed in Gadabout Gaddis in ME one day in my 3. The approach
Was over a mountain with tall trees and had to get down fast to the threshold. My power management was not good and came in hot ,landing after one go around, half way down the runway and almost ended up in the river at the opposite end. Bad experience, had the grass been wet I would have been swimming. I later found out this is an infamous runway for wet airplanes.
I spoke to my transition trainor, he asked my stalling speed full flaps;52mph.
He suggested practicing slow speed at altitude. Flying at 60 mph, I was able to arrest my decent to 0 with 2400rpm. However, I've learned 60 mph over the trees is to slow with little margin for error. The plane sinks like a stone and to easy to get behind the power curve. Not to mention very difficult to determine an accurate glide slope to clear the trees as the high nose pitch makes it difficult to see over the nose.
In sum, 70mph is a better number adding power in ground effect to soften the landing. The practice was invaluable for short field obstacle approaches. Better visibility over the nose to actually see the trees. This was also great practice for an emergency landing or an ice landing. How much power do you need to maintain 0 decent at slow speed? Fully loaded?
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Al Girard, Newport, RI
N339AG
RV-9
Last edited by agirard7a : 06-04-2016 at 05:46 PM.
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06-04-2016, 06:17 PM
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Join Date: Mar 2014
Location: Laguna Hills, CA
Posts: 1,805
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Good call to go around after the big bounce. Trying to re-flare with so little airspeed could have gotten ugly! 
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Doug
RV-9A "slider"
Flew to Osh in 2017, 2018 & 2019! 
Tail number N427DK
Donation made for 2020
You haven't seen a tree until you've seen its shadow from the sky -- Amelia Earhart
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06-05-2016, 07:26 AM
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Join Date: Aug 2012
Location: Garden City Texas
Posts: 878
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I have power lines 200' off the North end of my 1800' grass runway. What makes matters worse is the strip declines slightly to the South. I am still trying to find the best method of landing. 75 mph approach will bring me in steep enough but I have to goose it just before the flair. If your coming in with a 15 mph headwind at 75 mph and the wind lays down just before that flair it can ruin your day!
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06-05-2016, 06:47 PM
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Join Date: Dec 2014
Location: hilltop lakes' Texas
Posts: 135
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Flare at 60 nauts
My 8 although in the CG parameter is nose heavy. It is all but impossible to 3 point. It will decend right through ground effect at slower speeds. Of course as you speed up it will no longer 3 point. Have not flown since taking 23# off prop and 8# off starter and have not measured CG yet. I'm thinking it will be much happier landing.
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06-05-2016, 11:06 PM
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Join Date: Jul 2005
Location: Carefree Arizona
Posts: 61
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At 60 knots and the resulting high angle of attack the induced drag is very high and the flair at the bottom results in a spike of increased induced drag which adds to the sink rate with little vertical lift component...
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06-06-2016, 12:47 AM
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Join Date: Dec 2013
Location: SLC, UT (KBTF)
Posts: 240
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Power boost
A shot of power in the flare, not only compensates for the induced drag spike, but puts higher velocity air over the inboard wings and flaps (faster air over the lift producing surfaces) Done correctly, neither the IAS or groundspeed should increase. In military parlance, this is "blown lift".
Cheers, David
RV-6A
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06-06-2016, 04:57 AM
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Join Date: Jan 2005
Location: Ottawa, Canada
Posts: 2,357
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Quote:
Originally Posted by Mel
Something's not right. You should have plenty of energy to flare at 60 kts.
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60 kts on approach in one aircraft may not be the same as 60 kt on another, for several reasons:
- ASI instrument errors can be 5 kts, or more on each aircraft,
- static system position errors can differ between the two aircraft, leading to differences in indicated airspeed,
- one aircraft may have a leak in a pitot or static system, leading to erroneous airspeed indications,
- gross weights may differ between the two aircraft, leading to one aircraft being closer to the stall than the other,
- CGs may differ between the two aircraft. At the same gross weight, forward CG requires the tail to create more down force than at aft CG. The tail down force must be compensated by increased lift from the wing, so the total force = the gross weight. Thus the wing must create more lift at forward CG than at aft CG,
- Different props have different amounts of discing drag. Some props have enough discing drag at idle to disrupt the airflow over the inboard part of the wing.
Bottom line: while an approach indicated air speed of XX may be perfect in one aircraft, it may be completely wrong in a different aircraft.
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06-06-2016, 10:55 AM
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Join Date: Jan 2007
Location: Battleground
Posts: 4,348
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Quote:
Originally Posted by MikeyDale
I have power lines 200' off the North end of my 1800' grass runway. What makes matters worse is the strip declines slightly to the South. I am still trying to find the best method of landing. 75 mph approach will bring me in steep enough but I have to goose it just before the flair. If your coming in with a 15 mph headwind at 75 mph and the wind lays down just before that flair it can ruin your day!
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We have similar situation at our airpark due to tree's that also continue a few hundred feet down one side of the runway. It has "ruined" more than one persons day, including one of my buddies who was a little late on the throttle - bent gear, prop strike, etc... when the "bottom" dropped out on his RV7.
I have had a bit of this discussion before, but pulling back to arrest a sink is the absolute worst thing you can do. I hadn't hear the term "blown lift" before for a quick burst of power, but that is extremely effective. In those conditions, I also insure that I am not at full idle, just a touch of throttle seems to allow me to get off the post quicker. If the bottom drops out, I am on the throttle and pushing the nose down. You want airspeed, not more drag.
If you have an extremely short field, the "long props and big rocks" guys routinely drag them in under pretty high power. Watch the Valdez videos. I just don't like to be hanging off the prop near stall.
We all have had, and will continue to have, hard landings. More than once I have gotten out of the RV6 and fully expected to see some horrific evidence of damage to the gear. RV's are pretty darn tough....
__________________
Smart People do Stupid things all the time. I know, I've seen me do'em.
RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
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06-06-2016, 08:14 PM
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Join Date: Mar 2008
Location: Seattle
Posts: 1,412
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I notice a 9-10 knot speed loss from the round out.
I try to make closed throttle landings to keep my skills up. I notice when gliding down final with full flaps that the pull to run parallel to the surface slows the plane down that much. I have come down final too slow and that roundout pull has mushed thru and put me on the runway earlier than I had planned. Any less airspeed would have been an accelerated stall with an unpleasant arrival.
Jim Triggs, our EAA Chapter 326 Safety Guru has an excellent presentation on Low Aspect Ratio wings and RVs.
This condition applies to Thorp T-18s also.
This is probably where the advocates of Reserve Lift Indicators begin commenting...
__________________
Scott Emery
http://gallery.eaa326.org/v/members/semery/
EAA 668340, chapter 326 & IAC chapter 67
RV-8 N89SE first flight 12/26/2013
Yak55M, and the wife has an RV-4
There is nothing-absolute nothing-half so much worth doing as simply messing around with Aeroplanes
(with apologies to Ratty)
2019
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