Two questions: one on Antonov An 24/26, one on Ilyushin Il-76
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Two questions: one on Antonov An 24/26, one on Ilyushin Il-76
Dear all,
I have recently moved to Khartoum (HSSS) where I see a lot of interesting aircraft. Unfortunately, it is very difficult or impossible to get near them.
There are two observations that puzzle my mind:
1) The An-24 (or An-26, I cannot tell which one is which from afar) seem to retract the gear very, very late. Is is thie because you need all energy for the propulsion and must have gained sufficient altitude before you activate the hydraulics?
2) On final approach, the Il-76 comes in with a negative pitch attitude that is changed to positive only very late during the flare. I suspect this is due to the geometry of the wings which (I am guessing here) might be producing massive lift and massive drag at the same time so that you need increased thrust.
I would appreciate very much if someone knowledgeable could find the time to answer these questions which might interest others as well.
P.S.: An Il-76 coming in during the setting sun in the desert dust with all flaps down and all lights on is a marvellous sight .
I just saw that the An-32 is doing exactly the same. They actually disappear out of sight before I can see them retracting the gear.
I have recently moved to Khartoum (HSSS) where I see a lot of interesting aircraft. Unfortunately, it is very difficult or impossible to get near them.
There are two observations that puzzle my mind:
1) The An-24 (or An-26, I cannot tell which one is which from afar) seem to retract the gear very, very late. Is is thie because you need all energy for the propulsion and must have gained sufficient altitude before you activate the hydraulics?
2) On final approach, the Il-76 comes in with a negative pitch attitude that is changed to positive only very late during the flare. I suspect this is due to the geometry of the wings which (I am guessing here) might be producing massive lift and massive drag at the same time so that you need increased thrust.
I would appreciate very much if someone knowledgeable could find the time to answer these questions which might interest others as well.
P.S.: An Il-76 coming in during the setting sun in the desert dust with all flaps down and all lights on is a marvellous sight .
I just saw that the An-32 is doing exactly the same. They actually disappear out of sight before I can see them retracting the gear.
I think the AN26 is the military version and the AN24 is the civil version.
I’ve also noticed the nose down pitch on the IL76 which was designed for short unpaved runways in remote areas hence lift at low speed would be an important design requirement as would the ability to fly a steep approach over obstacles. Speed and range were also required once airborne so the basic wing couldn’t be too suited to short field performance as the drag at higher speed would be unacceptable therefore massive flaps were needed.
I’ve also noticed the nose down pitch on the IL76 which was designed for short unpaved runways in remote areas hence lift at low speed would be an important design requirement as would the ability to fly a steep approach over obstacles. Speed and range were also required once airborne so the basic wing couldn’t be too suited to short field performance as the drag at higher speed would be unacceptable therefore massive flaps were needed.
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1) I checked An-24 AFM and "at 3-5m switch ON gear brakes, after checking that 3 yellow flights are on (brakes applied) command FM to retract gears"
2) Same for An-12 - high speed approach drag counters with nose down. Also it makes visual approach more comfortable
2) Same for An-12 - high speed approach drag counters with nose down. Also it makes visual approach more comfortable
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Some corrections:
An-24 is a strictly passenger airplane. Well, unless they remove seats and load it via passenger and baggage doors
.
An-26 is just cargo wlth a cargo ramp. Could be military, could be civilian. Those in Sudan are most probably civilians.
An-32 is basically An-26 with huge engines taken from the twice heavier An-12, for better performance.
An-24 is a strictly passenger airplane. Well, unless they remove seats and load it via passenger and baggage doors
.An-26 is just cargo wlth a cargo ramp. Could be military, could be civilian. Those in Sudan are most probably civilians.
An-32 is basically An-26 with huge engines taken from the twice heavier An-12, for better performance.
Last edited by Romasik; 20th Feb 2018 at 18:12. Reason: corrections
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Thank you verc much, everone, especially Kulverstukas!
So it is really strange that they retract the gear so late, is it not? Do they maybe want to cool the brakes by leaving the gear extended? It's 38° C at the moment. That's warm but not totally unusual.
So it is really strange that they retract the gear so late, is it not? Do they maybe want to cool the brakes by leaving the gear extended? It's 38° C at the moment. That's warm but not totally unusual.
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Notice the negative pitch of the Boeing 377 Stratocruiser on final: (the B-29 had a similar wing with a similar approach profile)
Also, notice the negative pitch of this Douglas DC-4 on approach to landing:
Super Connie also with a negative pitch approach:
Also, notice the negative pitch of this Douglas DC-4 on approach to landing:
Super Connie also with a negative pitch approach:
Last edited by evansb; 1st May 2018 at 22:48.
