Optimal landing speed

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Steve
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Re: Optimal landing speed

Post by Steve »

My ideal landing is one that I hear, but not feel. I only achieve this about 20% of the time, with another 40% or so barely felt. Another 20% have a tiny bounce, 15% (usually with a strong and gusty crosswind) have a significant (to me) bounce, and 5% are embarrassing to a pilot with 36 years of flying experience. All are safe. I go around the <1% of approaches that don't meet my standards.

Steve

I've been on a good streak lately - 5 of my last 6 were heard, not felt!
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Re: Optimal landing speed

Post by BlueYonder »

Don Stewart wrote:My wife and I are both pilots. We land the plane by the numbers. On short approach we have the MP set around 12.5.
This puts us over the fence at around 75 knots. My wife had not flown for over eight months so she went up to do some T& G's. Using this landing technique she greased 5 out of 6 landings. She floated on one due to wind gust. Actually, I was pretty impressed. See video.
https://www.youtube.com/watch?v=qe0P4PSJRPk
This is interesting. I'm usually at 10-10.5 on base and final; might try a few with that boosted and see what happens. You're not the first to suggest that 70+ might be a better over-the-threshold speed.

In Vegas today for a day of training and practice, which got scrubbed due to 30kt gusts. Let's hope tomorrow is better.
The highest art form of all is a human being in control of himself and his airplane in flight, urging the spirit of a machine to match his own. -- Richard Bach
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Re: Optimal landing speed

Post by CFIDave »

If you look at the diagrams on Diamond's official checklist for the DA40-180, they recommend 11 inches MP for the approach when flying the traffic pattern.

Back when I had a DA40 and practiced pattern work, I would reduce MP to 19-20 inches for downwind, then reduce MP to 12 inches when abeam the numbers to begin descent. I tried not to touch the throttle again until on very short final. (For DA42 Austros, it's 50% power on downwind, then 35% abeam the numbers. :) )
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rwtucker
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Re: Optimal landing speed

Post by rwtucker »

CFIDave wrote:If you look at the diagrams on Diamond's official checklist for the DA40-180, they recommend 11 inches MP for the approach when flying the traffic pattern.

Back when I had a DA40 and practiced pattern work, I would reduce MP to 19-20 inches for downwind, then reduce MP to 12 inches when abeam the numbers to begin descent. I tried not to touch the throttle again until on very short final. (For DA42 Austros, it's 50% power on downwind, then 35% abeam the numbers. :) )
My 2007/8 DA40 is the same as your experience Dave. MP of 11 inches is too low in almost all circumstances. What works best for me is 18 inches downwind and 12-12.5 from there. Flying 11 could be dangerous for me in some cases. I would be trying to stretch.

Given what others are reporting, it looks like there are real differences. Prop? GW?
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Rich
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Re: Optimal landing speed

Post by Rich »

I don't seem to have these problems unless flare height is misjudged. FWIW, I use about 16-17 inches on downwind to maintain 90 knots with middling load. Then reduce to about 8.5 abeam the numbers to start the descent and generally wind up reducing from there as the approach progresses. Power at idle sometime before the flare and into the landing. Keeping more than idle power after the flare has the effect of extending landing distance.

Long ago the standard was to wind up at 1.3 Vso on short final approach (in non-gusty conditions). For me this works out to 55-65 knots at typical landing weights. If touchdown happens beyond about 45 knots (and sometimes it does), I find the stick is not all the way back and I can usually pick the plane back up by pulling back. 75 seems awfully fast. I don't think I've ever used anything above 70, and those times were in what I felt were unusually heavy landings or in gusty conditions.

A couple of adjustments I find handy:
- Adding half the gust factor if more than a couple of knots. 10 gusting to 20 means an additional 5 knots. A steady 30 knot wind without gusts gets no adjustment to speed (but a tighter approach).
- Recognize that the wind I experience coming down final usually drops off right around flare height. So if it's windy I'll add a few knots on final and expect it to drop off in the last 50 feet, dropping my airspeed. If it doesn't happen (rarely) my landing will be long. This may or not be a big deal and could require a go-around with a different strategy.
- The main runway at my home field (S39) is such that there is a kind of slight up-ramp at the departure end of 28, and the runway overall slopes slightly upward overall. So when landing on its reciprocal (runway 10), I'm actually going downhill, so even with the same procedure as 28, the flare will extend further and the overall landing distance will be greater than with 28. Not a big deal, as its 5700 ft. long. But at Sisters-Eagle (6K5), for example, it becomes an attention-getter. I have always landed uphill and taken off downhill there.
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Re: Optimal landing speed

Post by Antoine »

Today I did 2 landings and explicitly looked at the ASI (this made me realize that I normally don't).
At 300 lbs below MTOW I found 65 KIAS to be plenty enough when crossing the fence.
It did not cause the stall horn to blare and I think I could have come in a couple of knots slower.
In both cases power was at idle. This may or may not be the recipe for the smoothest landings but it definitely is the way to go if you think "what if I lose the engine in final".
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Re: Optimal landing speed

Post by BlueYonder »

Went out this weekend and did 10 landings, trying variants of the suggestions here. Both keeping the MP up to 11 and coming in somewhere in the 67-70 range over the numbers both seem to have made a real difference: 7 of the 10 were authentically greased, the kind you hear but don't feel. The other three had their bobbles, but they weren't bad at all. No bad drops.

So these suggestions really helped. Thanks to everyone who helped me think this through -- I feel like I hit a new and better level, and (better) am no longer rehearsing bad habits.
The highest art form of all is a human being in control of himself and his airplane in flight, urging the spirit of a machine to match his own. -- Richard Bach
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Re: Optimal landing speed

Post by Hans »

- I have been reading all the posts about landing speeds and configurations. I am certainly no expert at this but do know that every landing is different. There are so many factors in effect during this small time frame that the best advice I would ever give is " know the plane"....every landing is different, speeds are different depending on the angle of the relative wind just to name one....practice, practice....even the "experts" get it wrong once in awhile, so don't feel bad....plane is wonderful and very forgiving, keep at it.

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Re: Optimal landing speed

Post by BkFlyer »

Nice landings Debbie! :)

I find landing technique to be very interesting and as a result a large part of my flying is in pattern (especially during the dreary NE winters). There is so much good info on this thread! Here are some additional points I would like to add:
Diamond_Dan wrote:I am concerned about the pitch-up attitude - is there danger of a tail strike? The protective metal strip is pretty scratched up. If I am contributing to it, I can't tell when I am landing.
Buy small can of red metal paint at HomeDepot. Paint the bottom of the metal skid. You will lose bits of paint on every tail strike. It will be obvious when you scratch it.
blsewardjr wrote: -If I flare high and/or bounce AND I have lots of runway, I simply freeze or keep gently pulling back the stick AND add a small amount of power (depending on the sink rate) to (re) establish a gentle sink rate with the right flare sight picture. If I'm patient, the aircraft will easily settle down in a good touchdown.
Great advice. It's easy to read, hard to learn. I recommend anybody who has issues with bounces to spend an hour with a CFI working specifically on detecting excess sink rate, proper technique to correct it, and how to arrest bouncing (where there is adequate runway to do so!).

I have made some landing analysis videos for personal use, which I'm happy to share:

This one is 20-28kt highly variable crosswind:
https://youtu.be/fQGSSqRKXF4
I had difficulty staying on the ground due to gusts generating extra lift, followed by extra sink, and the additional speed I used to try to counter that...

And here is one on the opposite runway during calmer winds.
https://youtu.be/u2HRu3E_WyY
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Re: Optimal landing speed

Post by pietromarx »

I've around 1,000 hours in DA40s and have found that the landing speed is slightly weight-dependent, but consistency comes from managing airspeed through pitch and feel (meaning feel the wings as they come into ground effect). Flying it to the runway and then keeping the nose off seems to do the trick every time. I'm not an instructor, but I've had it pounded into me for decades to control the speed from the final 200 feet AGL / fence with pitch, rarely, if ever, with power. (IFR approaches are a different thing, of course, and require following a glideslope or glidepath.)

Keeping power in is a recipe for disaster in my mind as the entire point of landing is to get the plane to the ground at the moment of a fully stalled set of wings; having power in is almost guaranteed to make your landings idiosyncratic and unpredictable.

This said, I fly gliders and taildraggers, too. If I could make one recommendation to everyone here, it is to go out to a glider port and have them make you learn to do landings and good glider control. Once you've mastered landing airplanes without power on the same spot every time you will rarely, if ever, mess up another landing. I've probably gone around 2-3 times after having gotten a glider rating in 15 years, both due to gusty crosswinds. (Last week was fairly exciting here in CA...) Go-arounds are, of course, not available in gliders.

Similarly, if you go get a taildragger endorsement you will get to figure out exactly where and how your wings, tail, and wheels are with respect to the runway. To get my sign-off in the mid-1990s I had to demonstrate landing on the left wheel (alone!), keeping the plane running down the runway on the left wheel, and then taking off. Had to repeat it with the right wheel, both wheels, and then in a full-stall landing. Fun!

While the DA40 is famous for floating, the issue to my mind is really that it is a glider with an engine. Go fly some gliders (they're fun) and you'll find the DA40 to be easy. Get a taildragger endorsement and you'll look at tricycle gears as being kid's toys. :-)

My $0.02 ...


Peter
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