737 Undercarriage Drag

Thu Jan 06, 2000 10:15 am

Can anyone tell me if the the drag on the 737 is any greater than aircraft with main undercarriage doors?
If no how is it accomplished.

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RE: 737 Undercarriage Drag

Fri Jan 07, 2000 12:41 pm

Conjecture: I would think there is increased drag, especially considering the slight nose up attitude of all jets in cruise. However, the wheels fit quite snuggly in their opening and the outer side of the wheel has "hub caps".

So all in all, the increase in drag is probably more than compensated for by the reduced weight and engineering of wheel well doors.

Perhaps there are other explanations...

Best Regards,

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RE: 737 Undercarriage Drag

Fri Jan 07, 2000 1:14 pm

The B737 doors do entail greater drag. The B737-100 didn't have doors to save weight and also because there wasn't much room. Over a short-haul sector the benefits of low weight are more than low drag. The B737NG has the same arrangement to save weight and to give commonality with older models.

Basically, there is no real disadvantage for short-to-medium haul sectors for an airplane with no gear doors due to saved weight. It also reduces maintenance costs, though some suggest that there is increased damage from FOD.

Either way it is a minor issue. If it were a better system, however, I daresay that more airplanes would have this arrangement.
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RE: 737 Undercarriage Drag

Sat Jan 08, 2000 12:54 am

Doors were not put on the original 737-100 in order to save on weight and cost. They have been kept this way for commonality. You can either have the extra weight of the doors or the slight increase in drag. Basically they are equal to one another. Plus without the door it is easier to get in their and work on something.
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RE: 737 Undercarriage Drag

Sat Jan 08, 2000 4:36 am

Don't 737's (some of them, anyway) have some sort of donut that inflates after the gear is in and halfway seals the gap around the tire?