Uncommanded roll effect

[oreste]

Hi for all,i have one question for the staff:Why the torsion effect of the plane incoming at TAS over 1090 kmh?I report a poin of the manual of Mig 15 bis.

 

9.1.5. Uncommanded roll

Uncommanded roll can occur at high flight speeds throughout the altitude envelope. At altitudes below 4000 m, this can occur at TAS greater than 1070 - 1090 km/h (small needle on the airspeed indicator). As altitude increases, the true airspeed, at which uncommanded roll can occur, decreases. At altitudes above 11000 m, the true airspeed, at which uncommanded roll can occur, stabilizes in the 1010 - 1090 km/h range.

Uncommanded roll is corrected by applying opposite stick deflection to maintain the desired roll angle.

 

Now i report for eplain this wikipedia part of the True Air Speed:

 

The true airspeed (TAS; also KTAS, for knots true airspeed) of an aircraft is the speed of the aircraft relative to the airmass in which it is flying. The true airspeed is important information for accurate navigation of an aircraft. Traditionally it is measured using an analogue TAS indicator, but as the Global Positioning System has become available for civilian use, the importance of such analogue instruments has decreased. Since indicated airspeed is a better indicator of power used and lift available, True airspeed is not used for controlling the aircraft during taxiing, takeoff, climb, descent, approach or landing; for these purposes the Indicated airspeed – IAS or KIAS (knots indicated airspeed) – is used. However, since indicated airspeed only shows true speed through the air at standard sea level pressure and temperature, a TAS meter is necessary for navigation purposes at cruising altitude in less dense air. The IAS meter reads very nearly the TAS at lower altitude and at lower speed.

 

Now why you use TAS for parameter and not IAS? This is one bug for me and false the experience of the fly in this plane.I have this effect at hight altitude with air speed 300/400 max!?I stall at this air speed not Mach 1 Uncommanded roll...i dont think.Please consider my report,i love this plane and all your work and please,sorry for my english..

[lmp]

Now why you use TAS for parameter and not IAS? This is one bug for me and false the experience of the fly in this plane.

 

It's not a bug. Your Mach number is directly proportional to TAS, not IAS. Thus, when describing any phenomenon related to approaching or crossing the speed of sound, you will most likely use either Mach number or TAS. It may seem inconvenient to you but that's what the physics of flight are.

 

I have this effect at hight altitude with air speed 300/400 max!?I stall at this air speed not Mach 1 Uncommanded roll...i dont think.Please consider my report,i love this plane and all your work and please,sorry for my english..

 

400kph IAS at sea level means you're at Mach 0.33 (very much subsonic), but at 15000m it's Mach 0.87 (transonic). Your TAS goes from 400 kph at sea level to over 900 at 15000m. That's a very big difference!

[oreste]

The definiton of the IAS and of TAS explane all:https://en.wikipedia.org/wiki/True_airspeed All plane encounter different effect at same speed at different altitude.For same speed i mean same real speed not speed indicate,this speed indicate change cause altitude,the air is less dense over 10000 or 15000.When the air is less dense the indicator at the same speed have a reed different,less air impact the sensor and the sensor have different reed but the speed is same..the real fast is important for much think but not for stall for example or for max speed.Max speed cause turbolence,suffer,torment,impact over the plane but need incoming fast ad high pressure over the plane like the air at mach 1 fast .For example the FW190 D9 have all the max speed limit for different altitude indicate over the airspeed indicator,this indicator is for IAS.Is important,for example if you fly upwind or downwind the TAS could be the same but air over the plane is much or less and plane cant lift or encounter max speed effect,with same TAS the plane loses its wings...Thanks for respond my question and good work, I'm not here to disrespect or criticize,i only think better the plane for all.

Edited June 1, 2016 by oreste

[mytai01]

Now you know why there is a trim switch for roll!

[oreste]

I do not think that the shut off valve of aileron booster must have been for that reason, however, I have still a lot to learn and I'll keep in mind also this thing.