ORIGINAL: HarryC
ORIGINAL: erbroens
Well, I respect that you desagree with my observation of a plane landing unusually slow.
This weekend was fantastic.. we flew in a runway at the heart of the Amazon rainforest and I was glad my bud was able to land a Velox so neatly.. trying to retrieve a overrun model in that place could been deadly dangerous, LOL.
But I am not denying that crow helped. Remember what I said. If it's the type of plane that crow will help, then what he got was a better control of the approach and most importantly for a short runway a better control of the touchdown point. Consider the following choice:
1. Runway is 100m long, with crow the pilot can control touchdown point within first 20m, landing speed is a bit higher and takes 70m to stop. Has at least 10m runway to spare. Model is easy to get onto the runway and stop in the distance available.
2. Same but without crow, model won't lose height or speed easily, hard to aim for specific point on runway, tends to float, touchdown could be anywhere in first 50m of runway, touchdown at slightly slower speed and needs 60m, not 70m to stop but sometimes only has 50m remaining. So some landing will finish off the end of the runway despite being slower and needing less ground roll.
So if you have a short runway, using crow to control the approach and point of touchdown can over-ride the fact that it is slightly faster with a longer ground roll.
I have a 10-lb aircraft with fair wing loading of around 3-lb/sq ft, I tested the crow on landings and here’s what I found. With full flaps and leveled, after I deploy crow the plane reacts like it was going to slow down due to increase in AoA so I reduced power and AoA to descent. The descending approach was solid with slightly positive angle until ready for touchdown but I was surprise that the speed was too fast, when I chop the power it stall and fall around 2-ft with touchdown speed higher than normal.
So I decided to use negative crow like flaps and the result is really slower even at slightly negative angle (nose down), this time I need to put down elevator and additional power in order to increase speed. When I chop the power and flare the plane continue to float until touchdown at a very low speed.
I decided to put back to the original setting because I need slight speed at the same time lift on landing that I can be able to use even if the wind is not favorable.