JohnJ From United States of America, joined Jun 2000, 1620 posts, RR: 3 Posted (9 years 2 months 4 days 18 hours ago) and read 3151 times:
After viewing several photos of Airbus narrowbodies side by side, it occurred to me that some appear to have some type of hubcap/wheel cover on their main gear wheels, while others don't. Here's what I'm talking about - the Northwest A320 seems to be lacking these wheel covers, while the US Airways A319 has them:
JohnJ From United States of America, joined Jun 2000, 1620 posts, RR: 3 Reply 4, posted (9 years 2 months 4 days 12 hours ago) and read 2998 times:
Interesting. Brake fans could very well be what those are. They look just like the image Bruce posted. Wonder why some airlines go for them and others don't? I was just looking at an America West A320 picture I posted this morning and it appears to have them, too.
When you say brake fan, this is what comes to mind for me - I took the Continental Micronesia Island Hopper back in 2000, and this is what they use to cool the brakes after landing on some of the very short runways on the island route:
Dc10hound From United States of America, joined Dec 2000, 463 posts, RR: 6 Reply 5, posted (9 years 2 months 4 days 11 hours ago) and read 2990 times:
And to go along with the link to the photo of the A310 above (The system is essentially identical on the A310 and A300):
AAL A300-600R AMM 32-48-00-0
BRAKE COOLING - DESCRIPTION AND OPERATION
This equipment is optional.
The equipment enables high speed cooling of the brakes and therefore a
reduction in the aircraft turn around time in the event of short flights with high energy braking.
2. Mechanical Installation
There is one fan per main gear wheel.
Each fan is comprised of : -
- a motor
- an impeller
- a shroud comprising a debris guard
The fan motor is housed in the wheel axle, held in position by means of an adaptor assy. The motor drives the impeller which creates a flow of air from the heat pack to the exterior through the debris guard. The tachometer drive shaft passes through the hollow fan motor shaft. The tachometer is driven by the shroud.
Responsibility for the fans lies with the brake manufacturer. (??????.....)
For both Messier and Bendix the fans are manufactured by Technofan. Only the fan shroud differs.
3. Electrical Installation
The fan motor is of the three-phase type. The two motors in each twin-wheel axle have a common supply. With the landing gear downlocked, the fans are started by pressing the illuminated pushbutton switch 30GW. The fans must be started as soon as the pushbutton switch HOT legend comes on.
Illumination of the HOT legend indicates that at least one brake has exceeded the brake overheat threshold.
"Eagles soar. But weasels never get sucked into jet intakes.."
Buckfifty From Canada, joined Oct 2001, 1314 posts, RR: 21 Reply 6, posted (9 years 2 months 4 days 6 hours ago) and read 2941 times:
They look just like the image Bruce posted. Wonder why some airlines go for them and others don't?
They are just extra weight and cost for most airlines. Some may specify them because of operational reasons for certain airfields they fly into.
After long taxy times, brakes can get hot, and departures must be delayed to let the brakes cool down. However, that does not happen too often, except at airports where taxy times are long due to regular line ups or long distances. Adding brake fans may alleviate this problem somewhat, but the added weight will impose a weight penalty which is constant for all flights.