Advice for overshoot tendency?

[aro]

1.3 * stall speed is a good rule of thumb, and certainly gives you an idea of how much margin you have in the recommended speed. However, there may be reasons the factory test pilot recommends something else, e.g control authority at lower speeds. The book figures are a good place to start.

 

Another point to note, the manual recommends 65KIAS, but according to the IAS->CAS table this is actually closer to 6o knots. That makes it about 1.5 * stall speed which suggests you still have a reasonable margin. (Again, according to Jabiru website, check specific aircraft POH)

 

 

[motzartmerv]

Yes, I would want a good reason for operating outside the POH. 1.3 times Vs is normally VS not VSo. 1.2 for takeoff? Can't remember exactly. Interestingly, Jab made us modify the flaps on the 170 so the travel was less, but NO change was made to the stalling speed in the poh (full flap). Which we have proven by experiment to be wrong.

 

 

[aro]

Another point, don't be in a hurry to touch down anyway.

 

At Jabiru speeds, in a normal landing you probably travel as far along the runway before touching down as you do after - maybe further.

 

 

[Sapphire]

Another point, don't be in a hurry to touch down anyway.At Jabiru speeds, in a normal landing you probably travel as far along the runway before touching down as you do after - maybe further.

I had an a/c like that and rounded out will before the bitumen even started and holding off touching the tyres down about 100mm past-still not able to take the first taxiway without a strong headwind.

 

 

[David Isaac]

Yes, I would want a good reason for operating outside the POH. 1.3 times Vs is normally VS not VSo. 1.2 for takeoff?

Motza do ya mind if I correct you on that statement. Normally the minimum landing speed in the Pcharts of a POH is the 'short field' speed and is usually 1.3 x VSo (with full landing flap), not VS. The normal 'safety takeoff speed' (the speed the aircraft must have reached by 50') is 1.2 x VS. Well at least that is what I was taught all those years ago. LOL

 

 

[motzartmerv]

Not at all David, i thought I was wrong once before, but I was mistaken...lol...

 

 

[motzartmerv]

Yes ok. The short field landing appch speed is often quoted, but the minnimum landing distance is achieved with the short field approach speed (and is the distance quoted on p charts etc) not the normal approach speed, so I figured VSx 1.3 would be used to arrive at the 'normal approach speed'..And VSo x 1.3 would give you the 'short field approach"..??

 

 

[David Isaac]

Yeah, that makes sense after all we don't always do short field approaches ... Just checking on ya mate. LOL

 

 

[motzartmerv]

Lol...Thanx mate, I have to be carefull around you cunning old airdogs...:)..

 

regardless, even 65 kts seems fast to me, but thats what the manual states so we go with it. The 170 is a frankenstein design, and it flies like it..lol

 

 

[facthunter]

Big stuff sits right on the figures. Within 1 knot (believe it ot not) but your speeds are calculated an actual landing weight +gust and wind allowances. everything is taken into account.

 

Flying U/L's you have a recommended approach speed say 65 knots. To apply this speed all the time is BS. You might have a small pilot and fuel nearly empty or a couple of biggies going somewhere with full tanks. Could easily vary your speed by 5 or more knots. If you add a bit to this for mum or just to be safe , you can float for ever. Even the C of G makes a difference. If you are very nose heavy you need more speed as the downthrust on the tailplane is higher and the wing thinks it is weight.

 

IF you are heavy and she gets a bit slow without a quick check, or burst of power, you might drive it in. Gusty conditions dictate more speed and often a powered approach. You still have to get rid of the speed or if you touch down too fast the nosewheel can act like a wheel barrow / break off. Nev

 

 

[motzartmerv]

Yea Nev's right, and the quoted figures are at MTOW. So Technically anything faster than quoted would be adding to safety margins (sort of), but anything under it could see issues..;)

 

Stall speed and maneuvering speed both come DOWN with reduced weight.

 

Its interesting, our Bantam has a placard "minnimum pilot weight 70kg's.

 

We have to strap a drum of water in the pax seat on some solo's..

 

 

[David Isaac]

Yeah especially if that skinny kid Tomo was flying it LOL

 

 

[motzartmerv]

Hahaha.. Yes no doubt.. We used to use a bag of rice.. We had this tiny asian girl learning and....... never mind... Long story....

 

 

[ayavner]

Think I nailed it guys... had a STOL lesson this weekend, and I think it finally clicked :)

 

3 metres past the numbers on the first go, then right on em after that! :)

 

 

[motzartmerv]

Good stuff mate. :) control that speed= control the touchdown point.

 

 

[fly_tornado]

you're welcome

 

 

[jwn57030]

Flight sim is what helped me with that problem. I used to have a tendency early on too level off way to high, then stall and bounce off the ground. For me training on the flight sim helped me to experiment with rounding out at different heights until I figured out correctly on the flight sim. The funny thing is that I then ended up having the opposite problem of landing flat for a bit after that, but it eventually turned into a good round out and flare at the correct height with a soft touchdown.