Correct approach and landing

[eightyknots]

On VG XL it seems to be at least 10, 12 ... But i will test in january...

I would be really interested how it goes!

 

 

[erd72]

Now my sav is at 174 Kmh (tas) at 5000 rpm with my current pitch, i would be really happy if it match 10 kmh, so i will see how it works and inform you.

 

But first in have to redesign the part to be able to make some set up, the to drill this part. So it will not be before end of january...

 

 

[eightyknots]

Now my sav is at 174 Kmh (tas) at 5000 rpm with my current pitch, i would be really happy if it match 10 kmh, so i will see how it works and inform you.But first in have to redesign the part to be able to make some set up, the to drill this part. So it will not be before end of january...

Did you ever have success with the negative flap idea?

 

 

[Bruce Tuncks]

There was a Savannah around here written off practicing forced landings. If the margin between your airspeed and the stall sped is less than the gustiness of the wind then you are risking a crash, which is just what happened here.

 

All the postings about nice big margins and avoidance of gusty conditions are good stuff.

 

I think the insurance companies don't like stol planes...is this true?

 

 

[erd72]

Did you ever have success with the negative flap idea?

Hi,

 

I did not have the success expeced, probably for 2 reasons, too much negative angle, and too much drag with big wheels, but a friend achieve + 10 km/h with negative flap. But the rotax need to keep around 5100 /5200 rev/min to achieve this result.

 

 

[eightyknots]

Hi,I did not have the success expeced, probably for 2 reasons, too much negative angle, and too much drag with big wheels, but a friend achieve + 10 km/h with negative flap. But the rotax need to keep around 5100 /5200 rev/min to achieve this result.

Thanks Erd. It's probably not worth going that way then.

 

 

[Kogg]

Good evening. 
 

I have about 20hrs in a 2006 Savanah classic. 
 

slats are removed and vgs added. 

26” airstreaks for mains and 8.50x6 nose 
 

would like some feedback on approach speeds

 

setup 

23g fuel

passenger 1 150lb

passenger 2 240lb

 

im buffeting and beginning to stall power off with no flaps at 60 mph. The nose does not drop just mushes. 
 

im looking to figure out if this is related to the 26” tires or weight or both?  I have heard that some vg pilots keep approach speeds at 70 for this reason. 

 

[facthunter]

Do you know your Indicated airspeed is accurate? If you have stall buffeting, fly faster   A power off approach on a draggy plane is steep and has a higher RoD than you might like. Nev

[Kogg]

Thank you for the reply. Very new to this plane. I have an av30 and steam asi both indicating similar speeds. 
 

important to note I’m flying with an instructor who said the same if it buffets at 60 we will add flaps and approach with them. As soon as flaps are added buffet stops. Power on stall speed with no flaps is slow about 30 mph. 
 

he prefers to land with full flaps. I’ve also read that 10deg is preferd by most not full. 

[facthunter]

The plane is designed for short landings and low landing speeds .IF it's gusty use less flap and some power. Fly to the conditions. Keep talking to your Instructor. STOL planes aren't for gusty conditions. Nev

[Neil_S]

Hi Kogg,

 

I have a Savannah S with the normal 15" x 6.00 x 6 tyres. Had it for about 9 years.

I normally only use 1 stage of flaps for landing as it still lands plenty short. I am light and flying solo usually the plane would be about 500kg (1100 lbs)

I approach at about 50 knots (57.5 mph). As you are aware, the plane is draggy and those big tyres of yours would just make it more so.

I reduce to about 45knots (52 mph) on flaring and touch down at about 40 knots (46mph), nose high to keep the wheel off the ground for as long as possible. In gusty conditions I do a flapless landing slightly faster.

I prefer using the one stage of flap as it also means I don't have to reconfigure for a go around. My hangar mate has a Savvy VG with slightly larger tyres than mine (maybe 18"), but smaller than yours. I'm pretty sure he always does a flapless landing. 

If I feel the plane descending a bit too rapidly just before touchdown I add a bit of power to cushion the touchdown.

My home strip is about 1200m grass, so we don't really need to land short, although I am usually stopped in about 200 - 300m anyway. 

 

Hope this helps!

 

Cheers,

Neil

[fallowdeer]

Gidday Kogg

 

I can’t imagine flying the latter stages of a STOL approach in a Savannah VG at 60mph or more, it certainly wouldn’t work for me.  I’ve got about 800hrs in mine lots of short strips some down to 120 metres in length and one way.

 

For the very late stages of such approaches I favour a low speed, high AOA,high drag  powered arrival over the threshold with full flap.   Right on the left side of power curve….. Attached one is at 35knts IAS to touchdown aircraft is at about 420kg.

 

I think one thing worth keeping in mind when we discuss indicated speeds on STOL aircraft flying slowly is the huge pitot error at high AOA, what we’re seeing on the dial is a reference point and likely to vary greatly from CAS.

 

Often you’ll here someone say “my plane stalls at x airspeed blah blah” being some ridiculously low speed.  An aerodynamicist would be likely to tell them that just ain’t possible if weight, wing area, and coefficient of lift were plugged in…..

 

Hence our IAS in STOL ops is a reference point….

 

Peter

Edited April 29 by fallowdeer

[Marty_d]

That's a beautiful landing.

[IBob]

Hi Kogg, nice looking machine.

When ICP altered their design by removing the slats and adding VGs, they also altered the profile of the leading edge of the wing. However, it's not clear what difference the change of wing profile made.
Your best source of information for your aircraft would be JG, who pioneered the slats-to-Vgs conversion on that model and conducted a great deal of testing. He flies the same aircraft as you, with slats removed and VGs added, and I don't think he changed his wing. His website is Stolspeed and is a goldmine of information. Suggest you contact him, see if he is open to a conversation:

 

https://www.stolspeed.com/

 

I'm a bit puzzled that you say 'im buffeting and beginning to stall power off with no flaps at 60 mph.' I fly a Savannah S, the POH gives a flaps up stall speed of  30 to 35 kts depending on loading, and I know it cruises quite happily at 45kts.
I note you are flying pretty much at Max All Up Weight and it could be interesting to know what your Weight and Balance is.

 

 

[facthunter]

The BIG wheels are a lot of drag at a low position and that will require elevator downforce above normal which adds to the load the wing must carry. The buffeting  MAY be coming from disturbed  airflow on the tail feathers.. I can't see all that making more than a few Knots difference to the stall speed. but the whole thing should be sorted out at a safe height rather than on approach/landing. Nev

[Kogg]

Thanks guys 

 

we have spent a few hrs at elevation determining the stall speeds. 
 

Main goal here was to try and get possbile causes for the increased power off stall speed.
 

today landing with a little power made things much better. My power off approach speed is 70 to the threshold with full flaps it burns off quick in ground effect. If I float till about 30mph it will stall. Overall it’s enjoyable to fly. I will maintain this until I get a few more hrs and then start to slow it down. 
 

I have stolspeeds vgs installed and have spoke with him. It doesn’t sound like the new wing leading edge offers much in improvements.
 

I will fly with 13g of fuel and see if that changes anything. I may put some smaller tires on and see if that changes anything.    
 

 

[facthunter]

Extra weight will make it easier to fly. The engine gives you added control. When you have to, use it.  .  Nev

[HopeySav]

Totally agree with all comments regarding full flaps being too much. 
 

I have fitted one of Mark Kyle’s modified flap brackets (and throttle linkage mod) to my latest Savannah build which has 3 stages of flaps not 2 as per original fitment. I cannot believe the difference it makes having the modified flap bracelet, second stage of flaps is absolutely perfect for my 300mtr strip and still a very flyable aircraft compared to full flaps.

 

Got to hand it to Mark for his in-depth knowledge of the Savannah and his quality modifications that he produces.

[facthunter]

Full flaps is only for calm conditions and a short (or rough) runway. The advantage of a high drag approach is the Plane stops quickly when you take power off.. Nev