Retracts and speed
10-13-2010, 05:30 PM
#1
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Retracts and speed
This seemed like a good place to ask because I see speeds being accurately measured. And the question is; how much faster will a plane go with the wheels retracted?
10-13-2010, 07:05 PM
#3
RE: Retracts and speed
The answer depends on the plane. There might be some guys who have done before and after comparisons on the same plane and logged the speeds. I'd never consider using them on a speed plane, I'd rather go with a thin wing like a Q-40 has and use real thin gear like a Q-40 has.
My answer assumes that a Q-40 wing is to thin for retracts, of course.
The extra weight of retracts is more of a liability the smaller your model is.
At some point they make perfect sense, just not sure where that line is drawn with respect to the size of the plane.
My answer assumes that a Q-40 wing is to thin for retracts, of course.
The extra weight of retracts is more of a liability the smaller your model is.
At some point they make perfect sense, just not sure where that line is drawn with respect to the size of the plane.
10-13-2010, 08:10 PM
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RE: Retracts and speed
ORIGINAL: combatpigg
The answer depends on the plane. There might be some guys who have done before and after comparisons on the same plane and logged the speeds. I'd never consider using them on a speed plane, I'd rather go with a thin wing like a Q-40 has and use real thin gear like a Q-40 has.
My answer assumes that a Q-40 wing is to thin for retracts, of course.
The extra weight of retracts is more of a liability the smaller your model is.
At some point they make perfect sense, just not sure where that line is drawn with respect to the size of the plane.
The answer depends on the plane. There might be some guys who have done before and after comparisons on the same plane and logged the speeds. I'd never consider using them on a speed plane, I'd rather go with a thin wing like a Q-40 has and use real thin gear like a Q-40 has.
My answer assumes that a Q-40 wing is to thin for retracts, of course.
The extra weight of retracts is more of a liability the smaller your model is.
At some point they make perfect sense, just not sure where that line is drawn with respect to the size of the plane.
10-14-2010, 07:29 PM
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RE: Retracts and speed
Just something to think about...
Weight, is overcome by lift. It has some affect on speed, but not as much as you might think.
DRAG is overcome by power. It takes a LOT of power to over come a little drag. Frontal area creates big drag. round wire is BIG drag.
Yes, gear up, struts up, makes THAT much of a difference. Same reason we want a small diamater prop frontal area.
Weight, is overcome by lift. It has some affect on speed, but not as much as you might think.
DRAG is overcome by power. It takes a LOT of power to over come a little drag. Frontal area creates big drag. round wire is BIG drag.
Yes, gear up, struts up, makes THAT much of a difference. Same reason we want a small diamater prop frontal area.
10-15-2010, 08:34 AM
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RE: Retracts and speed
Weight is more of a factor to acceleration off the line and out of the turns. In straight lines or in a dive, it has little effect on top speed. I'm talking oz's, not pounds.
A stiffer/stronger airframe will be faster than a weak, vibrating airframe with the same amount of drag. Once again, within reason, it can't be a brick, but 4-6 oz on a 4lb plane is not going to effect top speed.
A stiffer/stronger airframe will be faster than a weak, vibrating airframe with the same amount of drag. Once again, within reason, it can't be a brick, but 4-6 oz on a 4lb plane is not going to effect top speed.
10-16-2010, 12:50 PM
#8
RE: Retracts and speed
Perhaps not faster but slower. Retracted gear in those open wheel wells may create more drag than the profile drag from a fixed gear in the identical average sport or sport/scale model and is heavier. If you could get perfectly fitting gear doors and eliminate the weight penalty, maybe there would be a chance of going faster. Hand-launched, gear-less, belly-landers may be the perfect alternative...
