The idea of landing a full-scale aircraft is to stall it at a height of a some inches. The standard approach is done with a speed of 30% above the stall speed. The aircraft will sit on the runway with nose slightly up.
If you fly the aircraft into ground, it will bounce, and the bounces will get progressively worse, unless somerhing is done and quickly. The rule of my aerobatic instructor was: 'The propeller will get hurt on the third bounce'.
-- -TV
That is how I land mine in still air. BUT I got caught out in wind
wind dropped and so did the model. No time to open throttle as only 4ft up.
--
"First, find out who are the people you can not criticise. They are your
oppressors."
- George Orwell
Bollocks.
Only per WWII tail draggers land that way,
What they do is arrange to be flying level an inch above the runway with PLENTY of excess airspeed. Then genbtly lose an inch of altitude. One the wheels are dwon then its full reverse thrist and airbrakes to keep it there,
The standard approach is
Exactly. ABOVE stall speed.
You didnt understand what I said. Perhgaps 'fly the aircarft all the way to the ground' is a better way of putting it.
The point is into a headwind you need to maintain an airpspeed of stall+ headwind so that if the wind drops to zero you dont fall out of the sky.
So fly well above stall and use elevator to 'coincide' with the ground, once there lose speed.
When I learnmt to fly mdels there was no throttle or elevtor control - every landing was dead stick glide to my feet.
I am good at that BUT its no way to land in gusty weather. So I learnt whith 3/4 channels to use first the elevator and then throttle and elevator to land 'actively'. Some of the models with steep glides wont land on their wheels any other way.
--
"First, find out who are the people you can not criticise. They are your
oppressors."
- George Orwell
And how much does the pressure change, second by second, due to gusting and localised turbulence etc? Presumably much less than this or the altimeter needle would be flickering visibly and would be difficult to read.
Some time I'll have to take the base station (*) of my weather station outside when it's windy and see what variation in pressure it records, though I'm not sure what electronic averaging there is between pressure sensor and digital display. Indoors it's shielded by the house walls so gusting isn't an issue.
I wonder if I could see a measurable difference between the weather station on the ground floor and in the attic. My weather station reports pressures to the nearest 0.1 mb, so *in theory* height differences between one floor and another ought to be detectable since 0.1 mb is about 80 cm.
(*) A remote sensor unit is used for ext temp and humidity, rainfall and wind speed/direction, but the pressure is sensed in the base station that is linked wirelessly to the remote unit and by USB to my PC.
Iam sure you could. I've known people use similar sensors to measure model plane altitudes.
-- Karl Marx said religion is the opium of the people. But Marxism is the crack cocaine.
Not sure it will but the pressure changes on a window due gusts are enough to make the glas flex. When we had single glazing and plain glass windows about 4' x 5' the center of that pane would move about
1/2" in response to gusts to 50 60 mph with a mean speed of 40+ mph. The double glazing with internal glazing bars forming six "panes" per top and bottom sash-a-like window still move but not as much, only about 1/4".Wouldn't be so sure, with a gale or more blowing outside the pressure inside in reduced by a few millibars. Venturi effect I guess. Sometimes the wind just stops, goes from 40 - 50 mph sustained to <
10 mph in minutes, there is a noticeable step up in the internal pressure as recorded by the weather stations pressure sensor.Ought to be able to. floor level ground floor to apex of roof above first floor won't be far short of 27' or 1 millibar.
-- Cheers Dave.
Nowhere more than at Gimly airport.
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Sounds like your approach speed was too low for the conditions that day. I must say that I've seen many more models flown onto the floor than I've seen making nicely held-off landings, so full points for doing it.
The usual UK gliding rule of thumb is to fly finals at 50 kts plus half the wind speed. That's safe for pretty much every glider type I've flown while still allowing nice two-point touchdowns to be made on main + tailwheel. I remember one blowy day a few years back: I got to 2700 ft on a winch launch (usual launch height on our field is 1400 ft) in an SZD Junior. Had a somewhat longer flight than normal for no-wind conditions and finished by crossing the airfield boundary at 70 kts with full brakes out to make a two-point landing. Fun.
Almost all gliders are tail-draggers apart from trainers, e.g. ASK-21, ASK-23, Grob G-103, Puchacz, Perkoz, PW-5 and PW-6.
I have to say that would be rather high for a fully held-off landing even in a full-size glider. Two feet is about the limit, with 1 foot being really nice. Anything much higher counts as an arrival rather than a landing.
-- Martin | martin at Gregorie | gregorie dot org
Found it on GoogleEarth, looking somewhat neglected in 2014 - there's no more recent imagery. Wikipedia tells me its where the Gimly Glider landed after an Imperial vs metric refuelling cockup. That makes it somewhat famous.
Two of the more 'interesting' fields I know are:
Both are 90 degree cross wind in good soaring conditions and both are winch sites. Eden Soaring is 2.5km west of the nearest soarable Pennines slope and The Mynd airfield is on top of its ridge with recommended landing approach speeds of at least 70kts if the slope is working. Its also about the only bungee launch site in the UK that is still used regularly. Both get decent wave in suitable conditions.
-- Martin | martin at Gregorie | gregorie dot org
Hello The!
Tuesday January 01 2019 19:28, you wrote to Tauno Voipio:
The angle used depends on the aircraft but generally it is between 1 - 2.5 degrees (up) for heavy twin and above and 2 - 5 degrees for single and light twins allthough most of the light twins I flew were happy with 2 - 2.5.
These numbers are for 'light' xwinds but in any event well below the max xwind limits. If that was not possible i.e., strong winds with a good xwind component the solution as in many was the use of liberal power and/or power gradient depending on a/c type and LW.
But hey that the way I fly and so far have never had a hard or uncontrolled handing - at least since stopped flying C150/152/172 types).
but there are other techniques for those if needed.
As an example flying in to Luton many years back as a gagle of a/c from a flying club using mostly Cessnas and my PA28-140 we found that the xwind was strong and outside limits for the high wings by a lot.
The piper was also out of limits but I had to get some pilot shirts and a replacement cap so really did want to get in.
I approached and landed using the starting right edge and the left short mid point of the runway with power and full flaps (which I would not have normally used for 30kts wind) and touched down and stopped in under a 100 yards - well under. Now the taxi-in was a little more tricky.
IT did have my attention though.
Correct and even tail dragers do not need to be stalled on but again good usage of power and flaps (if available) or even a side slide approach bet there again I have been know to use it on many other types - just depend on the circumstances lick much of flying.
Old flyer.
Vince
That is an entirely different scenario from an altimeter.
And more akin to an airpseed meter.
The pressure arises from momentom change as the glass is (somewhat) orthogonal to the dierction of air movement. The aim of an altimeter is NOT to slow any air down, just measure its pressure. So typically there will be something like a chamber with holes in it everywhere so ensure that the interiuors is full of air that is staionary WRT to the altimeter, and at the same perssuer as outside,
You can get that with open chimneys.
Mmm
-- "When one man dies it's a tragedy. When thousands die it's statistics." Josef Stalin
Yes, Exactly.
Well as I said I started out with rudder only. The model glided in at its own speed.
YTranbslating taht to model tersm tahts probably 10mph plus half the wind speed,
I wouldnt normally fly at all at anything over 10mph wind
-- There?s a mighty big difference between good, sound reasons and reasons that sound good. Burton Hillis (William Vaughn, American columnist)
I started off with Control-line and sport free flight (Aeromodeller plans) and then into single channel radio (Baz Bombs if you remember them
- lots of fun) and then switched rather abruptly into just flying competition Free Flight models: FAI power, 1/2A power, A1 and A/2 gliders with a bit of payload, scale and small rubber on the side.
I concentrated on concentrating on F1A (A/2 towline gliders) and 1/2A/F1J (small power models) from 1975 until 2004 when I jumped tracks again to full-size gliding.
15 mph may be a better estimate. An F1A glider (2.25m span, 15 dm^2 area, 420g all-up weight) glides at about 10mph - in flat calm you can run alongside the model and pick it out of the air as it comes down to chest height. Thats a moderate to slow running speed, so I'm guessing 10 mph.I've never seen any powered RC model fly that slow, though I suppose a park flyer might do so.
Free flight competitions are stopped when the wind speed exceeds 9 m/s averaged over 30 seconds. Thats 20 mph or 17.5 kts. For comparison I don't normally fly my (full size) Libelle if the wind exceeds 25kts at flying height. Above that the thermals get broken up by wind and I'd be flying landing approaches at 65 kts or a bit more.
-- Martin | martin at Gregorie | gregorie dot org
Mine was the sharkface...I remeber Baz Bombs OK, similar but a bit larger
and then switched rather abruptly into just flying
Ah well I fly old timers mainly.
And park flyers.
And gliders.
-- If you tell a lie big enough and keep repeating it, people will eventually come to believe it. The lie can be maintained only for such time as the State can shield the people from the political, economic and/or military consequences of the lie. It thus becomes vitally important for the State to use all of its powers to repress dissent, for the truth is the mortal enemy of the lie, and thus by extension, the truth is the greatest enemy of the State. Joseph Goebbels
The Natural Philosopher wrote
Apart from the Hubsan 501S drone I also have an Axion Laser Arrow, 160 km/h Modified the control a bit for FPV, and added target acquisition and tracking... It also has vertical take off, like this:
You are mistaken. Please go to the nearest airport with commercial flight operations and look at the attitude of an airplane at the touchdown moment. It will be about
5 degrees nose up.Besides starting with model airplanes in the 1950's, I've flown for over 30 years and instructed countless pilots.
-- -TV
Ypu are mistaken, Please go to the nearest airport with commercial flight operations and look at the *glide angle* of an airplane at the touchdown moment. It will be about
1 degree or less.The attitude of the plane has nothing to do with it. The space shuttle glies like a brick with a huge angle of incidence.
Myy poiit is that you do not 'stall' a plane onto the ground. Not since tiger moths and WWI biplanes.
You *fly* it in with airspeed well over stall.
-- ?Some people like to travel by train because it combines the slowness of a car with the cramped public exposure of ?an airplane.? Dennis Miller
On Mon, 31 Dec 2018 15:43:35 -0000, "NY" declaimed the following:
Consider the BMP180 sensor (I'm not certain if "discontinued" applies just to AdaFruit's board, or the sensor itself:
""" Pressure sensing range: 300-1100 hPa (9000m to -500m above sea level) Up to 0.03hPa / 0.25m resolution
"""
-- Wulfraed Dennis Lee Bieber AF6VN wlfraed@ix.netcom.com HTTP://wlfraed.home.netcom.com/
Hello The!
Wednesday January 02 2019 04:36, you wrote to me:
I will admit my use of the sideslip approach is usually when I am too high - possibly change of head wind etc, but mostly when doing a very tight circuit - military style. Not I should add with pax. Doing this stunt does need you to turn off the setting for rudder bypass which has different names depending on aircraft manufacturer as cross controls will be ignored otherwise. Yaw damper is the one they mostly use but there again . .
Vince
Somewhere there is footage on You tube of Ernst Udet landing a biplane without airbrakes using outrageous amounts of sideslip to essentially dump it on the ground at almost zero groundspeed.
-- Renewable energy: Expensive solutions that don't work to a problem that doesn't exist instituted by self legalising protection rackets that don't protect, masquerading as public servants who don't serve the public.
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