Hi - SP here, flare frsutration!

[MyMeowCat]

@ flarepilot: yeah that Stick and Rudder is a good book with lots of good stuff in it. Too bad I had to return it to the library --- I will have another look at it.


As for the vision thing ---- I don't have any corrective lenses. The idea of looking a round and even to the side is a trick for myself to prevent from staring and being fixated.


@ Andy_P: At my school they have us going final at 65 knots with 20 degrees of flap and go power idle before the threshold and glide in. In my 1977 C172 Skyhawk POH the approach speed is 55 knots to 65 knots so they have me going in at the highest setting. I think they do this as a safety factor against stall and wind. I don't think my instructors mind you being at 60 at the threshold (note this is only around the threshold).

Next time when you approach ask your instructor what he thinks of your glide slope...mine doesn't mention anything to me unless I'm dangerously off. I think they are seeing if the student can develop "judgement" on their own. My gut feel is that if you are steep then when you level off then your speed will increase because all the energy from that height gets converted to speed. If you approach at 65 then when your round out you are likely to be slightly over 65 for a while especially if you are steep.

The point is that your instructor may not be talking to you about your glide slope so you should ask while on final approach.


While on short final (on a zero wind day) see if you can pitch for 60 --- in a sense you are slowing it up a bit more before you get to the round-out part.

[phiggsbroadband]

Hi... I would just like to know what the OP does with the throttle during the approach... When I was pre-solo the instructor would ask what revs we should use. If it was calm the answer was 1600, if there was some wind then 1800, and if it was a lot more wind we would select 1900rpm, and hold that all the way down on base leg and final.

Nowadays I 'modulate' the throttle depending upon what the scenery looks like out of the window, which (nearly) always gives me a landing on the piano keys. (btw. most airfields I fly at have several hundred metres of undershoot.)

[Andy_P]

Nailed it folks, 3 consecutive landings near text book (although a high hour pilot might disagree!). To top it off, had to do right hand circuits today which I have never done before (noise abatement rules prevent left hand using this particular runway) . Moved onto flapless approach today. A couple of go arounds, I called it, instructor agreed so I guess my judgement is getting pretty good.

MyMeowCat, phiggsbroadband: doing 75knot base, 65knot final. Down to idle when the numbers disappear (so basically on the threshold). Drop down to 1700 rpm downwind with 10degree flap, then 1500rpm turning base with 20 degree flap. Final is 30degree flap and RPM depends on airspeed. OF course all this depends on windspeed, but for the best part I am flying early mornings before work so there is pretty much no wind at all.

MyMeowCat: we use full flap (30deg) on final. I think some of the older models have 40 degree full flap, which maybe to much in your case? As for glide slope, I can pick when I am to high or low now. I can tell when I am too high turning final without using altimeter (went through a stage where the FI blanked out all instruments except ASI) and this is normally the crucial part for me. If I am at the right hight as I turn final, my slope is normally perfect.

ktcy152, re cowl on horizon, pretty much what I did today. Think somewhere in this thread someone said the attitude should be the same as for takeoff. Thats what I did! (thanks to whoever that was!)

I can tell you, I am so over circuits now! Just need to practice some more circuit emergencies, but almost there!

[RatherBeFlying]

Approach Speed for Weight

Take out the aircraft manual and work out your gross weight with instructor and however much fuel you have aboard.

Approach Speed = root(actual weight)/root(gross weight) x Recommended Approach Speed (which is at gross weight)

So if you are 300 lbs below a gross of 2300 (depends on your model),

we would get 60.6 kt instead of 65 kt.

If you are making a long flight to a short strip, you might want to calculate your approach speed according to your expected landing weight. The 30 flap looks after extra energy and 40 is much better. Extra speed in a Tiger with small flaps is much harder to get rid of as I found out

[tecman]

RBF, that's a good exercise, especially in terms of seeing for yourself what sensible margins are. While I understand why instructors stress the need for adequate airspeed, I've found that in real life I spend more time thinking about how SLOW I can safely approach. As you point out, that involves a knowledge of the aircraft loading, conditions etc. While I wouldn't suggest that a 12 hour pilot focus too much on risk management, the reality is that for daily GA ops excess speed is a far greater danger than falling out of the sky, particularly on the marginal strips often encountered in rural Australia.

And yes, even little aircraft can be very humbling in the face of sloppy technique. I still chuckle when my 'big iron' mates hop into my P2002JF. Just as I did on my first circuit, they invariably find that unless they're properly on the minimum or back side of the power curve, they might as well give it away and have another go. We're kind of ready for it in a Lancair or similar but the insult from a puddle jumper is humbling indeed!

[ktcy152]

Congratulations

Congratulations !

[AirborneAgain]

Take out the aircraft manual and work out your gross weight with instructor and however much fuel you have aboard.

Approach Speed = root(actual weight)/root(gross weight) x Recommended Approach Speed (which is at gross weight)

So if you are 300 lbs below a gross of 2300 (depends on your model),

we would get 60.6 kt instead of 65 kt.

As tecman says, that's a good exercise, but you've got to be careful with what kind of speeds you are using. This calculation only works with calibrated airspeed (CAS), while POH speeds are always given as indicated airspeed (IAS). The difference between the two can be substantial. A C172S has a 10 (!) knot difference between IAS and CAS at stall speed with flaps extended. (Less at approach speeds.)

So to perform this calculation correctly, use the airspeed calibration tables/charts in your POH to convert the approach speed to CAS, calculate the new approach speed using the formula above and then convert back to IAS.

Alternatively, you could use the stall speed for your actual weight (from the POH) and multiply by 1.3 to get the appropriate approach speed. This is how the POH approach speed is calculated in the first place. (Again be careful to distinguish between IAS and CAS!)

[Andy_P]

Relax lads, I am only a 15 hour learner!! Still learning basic flying! At the moment I am still trying to get used to finding the correct attitude, air speed, bank angles, altitudes etc..

I have done plenty of reading on the maths part, but its still early days for me. Its been 15 years since I have done any study, so learning to fly, and learning to study again too! Its all starting to happen now, everything converging at one point. Its a good feeling actually, I get much pleasure from learning something new!

[localflighteast]

See , told you it happens!
It's a great feeling when it finally does.
congrats

[flarepilot]

one of the most important things about landing is knowing how to fly slowly


so, go up to a safe altitude (3000 agl or more) and configure for landing...fly as slowly as possible, note the airspeed.

then

stall the plane, note the speed

recover, get this part right, RECOVER

then take the speed you noted as stalling, multiply it by 1.3 and you now have vref on a nice day with steady wind.


try coming in at that speed on final, slowing down when you ''cross the fence'' to touchdown just above stalling speed...a gentle wheeze fromt he stall warning as the wheels touch is nice, but should be done with caution.


in that way you don't even have to pull out the poh and calculate


and what is over the fence/cross the fence? how about on glideslope at 50's agl or half your wingspan

[AirborneAgain]

stall the plane, note the speed
[...]
then take the speed you noted as stalling, multiply it by 1.3 and you now have vref on a nice day with steady wind.

This is not a good idea. The way you describe it, you will do the calculation using IAS, but you must use CAS.

If you take the C172S the OP is flying, at gross weight it will stall at 40 kt IAS (assuming the POH data is correct). 40*1.3 = 52. 52 kt IAS is about 57 kt CAS. But the CAS at stall is 48-50 kt (depending on power). Assume 49. 49*1.3 ≈ 64. So you will end up with a Vref about 7 kt too slow!

(Not incidentally, 64 kt CAS corresponds to 61 kt IAS, which is exactly the Vref figure given in the POH.)

[Crash one]

I would suggest that a 172being flown solo or 2up with no baggage is unlikely to be at gross weight. 1.3 times Vs (IAS) should be perfectly good enough. I think this is developing into a mountain/molehill scenario. Taking it up to 3000 ft & playing with it would, in my opinion humble or otherwise, be a good exercise.

[AirborneAgain]

I would suggest that a 172being flown solo or 2up with no baggage is unlikely to be at gross weight. 1.3 times Vs (IAS) should be perfectly good enough.

It doesn't matter if the aircraft is at gross weight or not. I used gross weight because the POH had figures for that which I could use as an example. The C172 has a substantial difference between IAS and CAS at high nose-up attitudes. If you did the calculation using a lower weight stall IAS you would still end up with a too low Vref for that weight.

I think this is developing into a mountain/molehill scenario.

I don't think so. In my example, calculating with IAS would lose you half the margin to stall that you are supposed to have at Vref.

Taking it up to 3000 ft & playing with it would, in my opinion humble or otherwise, be a good exercise.

Now, that is something I think we can all agree on!

[Crash one]

Can't remember who it was, Alex Henshaw perhaps who used to stall the Spitfire in the downwind, & then land at that. Dependent on fuel load etc. Shirley if yr worried about 1.3 not being enough at IAS then go for 1.5 or FEEL the a/c. At what point does one do all this calculation? Landing speeds will vary a bit day by weather by fuel load etc. Mine stalls at 40knots at gross clean. In a light steady wind,solo, half tank, half flaps its perfectly controllable landing at 45.
It is not a 172.

[flarepilot]

oh, here is an article that shows others think like I do


WHAT IS FINAL APPROACH SPEED?

[flarepilot]

I took a look at the POH for this plane...now I remember why I hate cessnas so much


a piper will give you information for different weights

so, like I said, go up, find out what the stall speed is for your exact weight(safely)in KIAS, then convert it to KCAS, multiply that by 1.3, convert that number back to KIAS and come in at that speed.

but you see your poh doesn't conceive flying below max gross speed for landing

or, go out and rent a piper, and use their poh (last one I looked at would give you lower weight numbers) and see how things should work


I think cessna decided max weight was good enough and safe enough...but I don't think it was precise enough. but it makes the lawyers happy doesn't it.

and funny how we use INDICATED airspeed for flying and indeed the bottom of the white arc is indicated speeds.

good luck, fly safe and add five knots for unknown wind, non standard annemometer height or the wife kids or tax collector

[Crash one]

Fly the aircraft, find out the stall speed, do not make it complicated, & Certainly Do Not Add five knots for anybody. Otherwise you will end up at cruise speed & that is not a landing speed.
I give up!!!

[Desert185]

MyMeowCat

While on short final (on a zero wind day) see if you can pitch for 60 --- in a sense you are slowing it up a bit more before you get to the round-out part.

Primarily for the OP, who is trying to break the code:

If you only pitch, you most likely will leave the desired profile. How about pitch and/or power for 60? Both influence and control airspeed and profile to one degree or another. Fast, slow or on 1.3 Vso, the means to correct/maintain may depend more on one that the other. Blend the two, with more of one than the other depending on the situation of current speed, weight, turbulence, downdraft/updraft, etc. When really slow, it is possible (and preferable) to flare with power.

Pitch alone doesn't always control airspeed on final. Its only simple after a lot of practice.

Consider moving the seat height up or down (if possible) for a sight picture that suits you, and scan from the nose to the end of runway or horizon until you find your sweetspot to judge flare height and flare control.

Configure earlier, trim and stabilize the speed for more accurate landings. This is especially important when in the backcountry when normal patterns/circuits are not possible due to terrain/obstructions at different airports. This works even at same-same, cookie-cutter, flatland airports. A good landing begins early in the approach. Good luck.

[MyMeowCat]

Once your figure out that the approach and speed are fixed then that leaves the flare itself. The next trick to learn how to round out and level off. I often pull back much or fast. I'm thinking while in landing attitude slight nose down I might only have to pull back the controls about 1 in maybe about 2 seconds?

[Andy_P]

So here I was, rounding out and flaring ok. Today, thrown in the deep end with crosswind landings! Right on the limit of 15 knots too. Baptism of fire for the learner! Was very gusty too. I probably managed 2 out of 7 landings well, the rest were terrible. Only 2 go arounds today!


The thing that got me the most today, was turning onto the crosswind leg (which was more downwind than crosswind) how much the gusts roll the aircraft over, then when you roll it back the gust goes and you are flying straight again, then bam, hit again.

FWIW, I am a racing sailor, so I understand wind patterns very well. Its amazing how useful the water is when you are up in the air too. I already know how to read wind gusts and direction and it certainly gives you a huge advantage when learning to fly.