I know this isnt my haunt, its the AFM forum but the other day I had an idea, yes even us blondes can have ideas.
When aircraft land their tyres spoke as they qwucikly speed up to the planes speed (if thats wrong sorry please correct me) and I know the tyres do have a short life.
But why has someone or maybe they have and it was unfeasble attach fins to the wheels so when the undercarrige is lowered the air flow spins the wheel to the same speed as the aircraft.
Just wondered what peoples opinions were on this idea.
————————
Now where did I put that cocktail
By: coanda - 14th February 2002 at 18:34
RE: Wheels Spinners
regards stabilising fins on wheels. if you had one, to stop the wheel spinning, it would cease wheel spin, but would also place undue strain on the axle of the wheel, since of course anything like a fin-even plate shapes, will generate lift at speed, thus having the tendancy, through the lifts resultant force, to push the wheel upwards, and coincedentally inwards.
if you had spoked fins on the wheel hubs, you would get a water wheel effect, much the same way as axial flow compressor turbines work, because the air would cascade through the spokes, bringing with it, different areas of high/low pressure, promoting centripetal motion, ok at some point the air would be going soo fast as to stop the wheel hub spinning.
the wheels in either of these configurations would increase drag, and therefore absorb more energy, increasing take off runs. the wheel does rotate slowly when lowered inflight because of the airflow, but this is not significant enough, as would be with stabilising fins to cause drag problems.
it is almost a good idea to have your wheels spinning slowly- but not stationary, when you land because, on touch down the wheels will absorb some energy in accelerating to the speed of the aircraft, in effect HELPING to slow it down. fin stabilised wheels would be very hard to balance due to varying airflows over the fuselage and imperfections in weight and construction, during manufacturing!!
if you really want motionless wheels on touch down, why not have a microswitch, as is done with weapons arming and even radar activation on some aircraft that keeps the wheel brakes engaged until 1kg of upward force is felt on the wheels, activating the microswitch which disengages the brakes. this will not affect the aircrafts aerodynamic performance while giving the desired result.
coanda
By: KabirT - 14th February 2002 at 16:00
RE: Wheels Spinners
Bhoy the Russians attatched the fins in the spokes section of the wheels.
By: KabirT - 14th February 2002 at 15:58
RE: Wheels Spinners
This has been tried before Kelly….first by the Russians while carrying out various new techniques and tactics in there Il 86 ‘Maxdome’ varient which was supposed to be shielded against nuclear explosions. During its initial stages…..fins WERE attatched to it for experiments, but the Russians dropped the idea for it according to them was affecting the performence of balancing the speed during landings, also during take-offs it was tending to reduce speeds…..although by a small margin.
Some new features by the Russians in there Maxdome(not the real ASCC code name)were a drogue housing for VHF trailing wire antenna(the Boeing E-4B also uses one which is approx. 8 km long). Also it is known the under carriage pods of the Maxdome carry electricty generators!
By: Bhoy - 14th February 2002 at 15:46
RE: Wheels Spinners
umm, because then they would land on the fins, not the tyres…
Sign In
February 14, 2002 at 3:13 pm