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iaw4

500fpm, 60 knots, 15 degrees flaps

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I am trying to guestimate base rpm settings.

I cannot hold the speed, esp VS, precise enough (mountains nearby) to have full confidence in my own numbers, so I though I would query a few of you.  as for me, I have to visually average my descent rate from occasional glances.  (I should start timing the descent from pattern altitude, which would be more precise.)

here is what I get:

* a setting of about 2,800 rpm with 15 degrees flap holding 60-65 knots gives me about 400-600 fpm descent [on pretty close to a standard day, full fuel, and 330 lbs of passengement.]

* a setting of 3,200 rpm, I am closer to 200-300 fpm descent rate.

* (guessing from the above, at 4,000 rpm, I can fly along level at 60-65 knots.]

does this seem right to you?

/iaw

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thank you, everybody.

PS: one of my struggles is that the CTSW is so light, that its characteristics change quite a bit not only based on slight wind differences but also without a pilot [instructor] in the right seat.  so, this is all very helpful basic information trying to adjust to single-pilot landings.  so far, I have tended to end up too high when alone, and I spend most of the runway wrestling the airplane down.  not good.

 

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2 hours ago, iaw4 said:

I spend most of the runway wrestling the airplane down.

This says you are arriving at too fast a speed.  Solo I'm in the high 40's up to 55kts, (30 degrees) 60 is on the fast side.

Try forgetting the numbers and instead on approach nudge your throttle to keep your aiming point at the same spot while your speed is trimmed for 55kts.  If your off won't be by much.

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On normal final, at 500 feet and 15 flaps, I am already too high without any throttle.  So, I need to fly a longer final, or be lower.  The airplane is so light, it requires vigilance to fly a standard “same point on windshield”, too.

i suspect it is not intrinsically harder to land a ctsw, but it is different enough that it requires a lot of adaptation.  The issue for me is that the adaptation is for flying without a safety in the right.  I can fly with the safety.  A few more hours and I should be good...

 

what is the stall speed on 15 flaps?  What is the bottom of the power curve?

 

 

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Stall speed with 15° flaps is 42 kts, 55 kts is 1.3 Vs with 15° flaps. If you slow it down your approach path will be steeper, even if you are not coming down as fast.

There are so many factors that effect where and how much throttle you will need. What is your idle speed sitting on the ground? Are you flying a standard 1000 foot pattern? Are you at a busy airport following other aircraft, or can you set your own pattern size? How coordinated you are flying and wind are also factors.

When I am flying by my self I put power to idle abeam the numbers, and still fly a fairly big pattern with 15° flaps.

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thanks, tom.  this makes good sense to me.  I had looked at the POH, and it had 44 knots on -6, 42 knots on 0, and 39 knots on 40.  like an idiot, I stared at this and thought "why none at 15 flaps?"  the obvious answer was of course to look at the numbers until it would dawn on the reader that they are all indistinguishable between 39 and 42.  hello real world.

is 1.3*Vs (55 knots) about the bottom of the power curve with 15 flaps then?

yes, many factors, and nothing is precise.  I can pretty much fly my own pattern.  my airstrip is a long 4,000 feet but thin, and with high palm trees on very short final.

yesterday, I was flying about 1 nm finals.  I had been targeting 500 feet on turn to final, and flying with about 2800 rpm at 60 knots 15 flap.  this ended up reasonably ok (little but not much long) with a 200 lbs passenger, but it ended up too high without one.

so, I think my next solo flight attempts will be experimenting with (stabilized) 2,400 rpm w/ 15 flaps, target airspeed of 55 knots, and 1.2 nm finals at 500 feet altitude outset, 400 fpm descent, correcting with power.

will try out when the weather improves 🙂

 

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Iaw4, learn to slip the airplane when you are high.  I try to be high rather than low, because it’s safer if the engine fails.  You can be VERY high, very close to the runway, and with a full slip you can get down and still land on the numbers.  Just leave the slip in until you are on the glideslope you want.  When you get good at it you can pull the slip out very close to the ground if needed, 5-10 feet.

Just be aware that the CT wants to pick up speed in the slip; watch the airspeed and use stick back pressure to pick up the nose as necessay to keep your sped where you want it.

I probably slip to some degree on half my landings.

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12 hours ago, iaw4 said:

yesterday, I was flying about 1 nm finals.  I had been targeting 500 feet on turn to final, and flying with about 2800 rpm at 60 knots 15 flap.  this ended up reasonably ok (little but not much long) with a 200 lbs passenger, but it ended up too high without one.

so, I think my next solo flight attempts will be experimenting with (stabilized) 2,400 rpm w/ 15 flaps, target airspeed of 55 knots, and 1.2 nm finals at 500 feet altitude outset, 400 fpm descent, correcting with power.

will try out when the weather improves 🙂

 

IMO, you should try for shorter finals, not longer ones.  The shortest final you can make and get a good stable approach is ideal, IMO.  If the engine fails, being over a mile from the runway can be problematic.  Many fly-in procedures specify flying a tight pattern to expedite arrivals.  And lastly, some pilots get frustrated when others fly longer than necessary patterns, as it slows down the whole pattern.

I often turn final a quarter mile or so from the runway.

YMMV, this advice is worth exactly what you paid for it.  😀

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I'm with Andy far shorter finals, 1/4 to 1/2 mile instead of 1 mile.  Steeper is best with obstacles.  One mile feels silly in a CT to me.

If you use flaps (30) idle power setting and full rudder deflection to fly the whole approach as short and steep as possible you can turn for the numbers from abeam the numbers.  Slipping a 180 to the numbers gets the final leg's length down to zero.   A CT can come down super steep and if just idle and flaps its still very steep.  You are stuck up there cause of the 60kts and 15 degrees.

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My opinion is that a CT is so very lightly wing loaded that I am better off flying to the numbers with small but continuous adjustments to keep my speed, course, heading and attitude as desired.  The idea that I can set up a 500fpm stabilized approach right into the final stages of the landing is often spoiled by sink, or shear and adjustments are needed mostly because I'm so light and somewhat slippery.  I just don't have the drag profile to be that stable and instead keep flying it all the way to the chalks.

After 12 years of flying my CT I have never gone to predetermined settings for approach and landing instead I adjust till my target is where it belongs.

I do like 500fpm for my initial descents :) 

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If you fly 0.5 mile finals, at what agl and speed are you on turn to final?

a basic pattern profile is a good thing to start out with, even if landings are all different and the ct is too light for a standardized stabilized final.

I am not enthused about 30 flaps, given the added susceptibility to small wind gusts.  But maybe it is a good idea...

 

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15 minutes ago, iaw4 said:

if you fly 0.5 mile finals, at what agl and speed are you on turn to final?

a basic pattern profile is a good thing to start out with, even if landings are all different and the ct is too light for a standardized stabilized final.

I am not enthused about 30 flaps, given the added susceptibility to small wind gusts.  But maybe it is a good idea...

 

I keep it simple.  A beam the numbers I chop the power and deploy 15 degrees, just wait 3 seconds for 62kts and then 30 degrees.  At this point I trim for 55kts and fly 55kts on downwind, base and final.   The whole thing is basicly hands off relying on pitch trim.  500' AGL is nice for turning final and lower can work well to especially on a tight pattern.

wind gusts are the reason I want 30degrees.  If I land with 30 I tend to land and 39kts but If I land with 15 I tend to land faster even much faster. The gusts are not a problem in the air because the Rotax responds in an instant.  Where I don't want to be is with my mains on the runway faster then 39kts where I have no answer to the wind gust.

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Ed---in 12 years, I will probably ignore all the numbers and just land instinctively, too.  actually, probably in a few months.  but, right now, I want to develop the instinct for this particular airplane.  and most importantly, develop the peripheral vision to judge altitude over the runway.  and wrestling with being too high and fast at the same time makes this a lot harder.

I don't like sideslips as the standard goto for landings.  I like them fine for getting down in a hurry when needed, but I do not want to have to plan for them.  I have plane control surfaces for a reason.  😉I would rather get the drag from 30 flaps if sustained and planned for.

I always thought a little faster and less flaps are less susceptible to gusts, especially side gusts.

ok.  new plan---2,400 rpm w/ 15 flaps abeam the numbers, target airspeed of 55 knots, 30 flaps on base, and 1 nm finals at 500 feet altitude outset, 400 fpm descent, correcting with power.

 

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30 minutes ago, iaw4 said:

I always thought a little faster and less flaps are less susceptible to gusts, especially side gusts.

well sure but its still easy.  getting gusted with 2 or 3 wheels on the runway and flying speed is not easy.

 

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can someone please confirm for me what the bottom of the power curves are for 15 and 30 flaps?

 

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57 minutes ago, iaw4 said:

 

can someone please confirm for me what the bottom of the power curves are for 15 and 30 flaps? 

 

I don't think most here are used to thinking 'bottom of the power curve'.  Would that be same as Vmd?  Perhaps you could explain it and how its used?

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Its the transition point to slow flight.  I am interested in it because the aircraft responds less naturally and quickly to variations in throttle in slow flight.  The handling characteristics change.  Yes, i have always flown well in slow flight, and the ct is easy to fly in it, too.  Still, the most pleasant, natural, and easy flying for me is at this bottom.  It just is most intuitive.

there are long discussions on the web about vmd and the bottom, especially as far as jets are concerned.  But I don’t really care about this.

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48 minutes ago, iaw4 said:

 

Its the transition point to slow flight.  I am interested in it because the aircraft responds less naturally and quickly to variations in throttle in slow flight.  The handling characteristics change.  Yes, i have always flown well in slow flight, and the ct is easy to fly in it, too.  Still, the most pleasant, natural, and easy flying for me is at this bottom.  It just is most intuitive.

there are long discussions on the web about vmd and the bottom, especially as far as jets are concerned.  But I don’t really care about this.

Thanks,

CT flaps do work nicely in the right speed range and not so much at the slow end.  An easy way to make it work is to fly it as a 'pitch attitude' airplane.  Include an exaggerated nose down pitch change when going to 30 degrees to get it right.

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9 hours ago, iaw4 said:

I don't like sideslips as the standard goto for landings.  I like them fine for getting down in a hurry when needed, but I do not want to have to plan for them.  I have plane control surfaces for a reason.  😉I would rather get the drag from 30 flaps if sustained and planned for.

 

 

Why *not* plan to use a slip if needed?  You plan to use flaps, what’s the difference?  Shouldn’t you plan to use whatever control inputs you need to, in order to make a good approach and landing?  Why hamstring yourself by taking a strong tool off the table?  You have to slip to land every single time you land with a crosswind, so it’s not like you’re never doing them; even the “kick” part of the “crab and kick” crosswind technique is a transition to a slip.

What if you have full flaps in, are slowed way down, and it’s still not enough?  I regularly land at grass fields that require 30 degrees of flaps, 48-50kt approach speed, AND a healthy slip to get down over the trees and land without floating halfway down the rather short runway:

https://youtu.be/y5PHKyAPH84

What if you are engine out, and you are too high to make your chosen landing field, even with flaps?

Once your flaps are in you are generally stuck with them until landing.  You can put a slip in until you are on your desired path and then take it back out, super useful for fine tuning an approach.

Slips are something that should be in every pilot’s toolkit, they are just way too useful to leave on the ground, and the CT is great at them.  I’d rather have an airplane that can slip like hell than one that has flaps at all.  My experience is that many pilots avoid slips out of unfounded fear or a lack of understanding of the maneuver.

Again all IMO of course.  I’m not coming down on you or your skills, just trying to persuade you to give slips a try when you are high on final.

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I think FD left out the AoA from the Dynon---there was no audible warning on practice stalls.  has anyone installed one?  (can it be set to raise hell audibly at a certain angle?)  if I did have one, I would be more aggressive alone.  right now, I am not even a chicken when alone.

there is a small possibility of entering a stall/spin, but it's ok.  a slow-speed forward slip is a little too close to comfort for me, at least for quite a while.  I could forward slip aggressively gaining speed, and then go back to slow flight.

but this is not even the main reason.  I used to slip my Vans RV-9A quite regularly, and it was very effective.  however, when I tried it with an instructor on the right, the CTSW did not bleed off as nicely as the RV-9A.  I am guessing that this is partly due to the thin tail boom and the relatively round passenger compartment profile.  yes, slipping  is a tool and it works, but it did not seem to be a very sharp tool...at least the few times I tried it.

/iaw

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If do don't pick the nose up when you slip, the CT picks up speed fast and the descent rate will not be high.  If you hold backpressure and keep the speed to normal approach speed (say 55kt), the increase in descent rate is impressive.

For a stall/spin to occur in a slip, the high wing (the one with the higher AoA), has to drop and come out underneath the airplane.  You basixally have to hold the cross-controlled condition through a full half turn of the incipient spin, several seconds.

If the high wing starts to drop, you simply re-center your controls, decreasing the high wing's AoA and the issue would resolve.  You also can push forward on the stick for good measure, but that probably would not be necessary.

I have done full slips with the rudder to the stops as slow as 46kt, and have never had a wing start to drop on me.  The CT is incredibly docile.

But to each his/her own.  I understand being conservative, especially as a new CT pilot.  But don't be afraid to explore different techniques, the CT really rewards pilots with a large repertoire of "tricks" they can dip into, especially regarding landings.  Each one is unique, and if you try to make each a cookie cutter, by the numbers affair, you will often be left scratching your head as to why it didn't work out as planned.

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