4 ms·

> They put fans on tall poles in their orchards and run blowers up and down the rows. But this isn’t usually effective. From my armchair I wonder what the reas

by w-m 7y ago

> They put fans on tall poles in their orchards and run blowers up and down the rows. But this isn’t usually effective. From my armchair I wonder what the reason is for not having a ground-based solution. Running a small vehicle (lawnmower-size?) with a fan mounted on top between the trees seems like a much more economic way to have the same effect. Is there not enough space between the trees to pass through (but then, how would they harvest)? Do the trees suffer, branches break if the air flow comes from below / from the side?

Scoundreller 7y ago
It’s a time issue. The helicopter can quickly buzz a lot of more field than a tractor can.
maxerickson 7y ago
The helicopter is a 250 horsepower, 33 foot fan.
- dsfyu404ed 7y ago
  So 3hp/sqft (power/(area/time) would be better but we don't know how fast the chopper is moving while it blows the water away). That's not that much power. That's on the same order of magnitude as snow blowers Obviously not all hp are equal and you get into a discussion of cfm, specific impulse, etc, etc. but power/area should be a pretty ok proxy for drying power. It shouldn't be that hard to build something that looks like the bastard child of a concrete pumper and a pine mulch blower that can either fit in the bed of a pickup or runs off a tractor PTO and can apply more than enough airflow to destroy your crop if you use it wrong. Maybe include a big rubber hose (like those temporary water mains) on the vehicle to give the tree trunks a good whack as you drive by.
  - maxerickson 7y ago
    I think I might try to make a contraption with a 33 foot fan that sort of hovered over the trees.
teh_klev 7y ago
> I wonder what the reason is for not having a ground-based solution. Running a small vehicle (lawnmower-size?) with a fan mounted on top I imagine the important part of the "drying" process/action is being able to give the branches a bloody good shake to dislodge the water droplets. It's likely that even very large fans aren't capable of moving that much air (compared to a helicopter's blades). Then there's also the question of even if you could trundle around the orchard with a set of fans able to push that much air I can imagine it would be comedically unstable and dangerous :) [edit: typo]
- ehnto 7y ago
  I wouldn't go anywhere near such a device. The amount of energy in a rapidly disembarking blade would be terrifying.
- dsfyu404ed 7y ago
  >I imagine the important part of the "drying" process/action is being able to give the branches a bloody good shake to dislodge the water droplets I imagine your typical 5-ish liter v8 coupled to a big centrifugal blower is more than capable of providing a "bloody good shake"
logfromblammo 7y ago
The article mentioned that smaller helicopters can't do the job because they don't move enough air. It likely has to be done from above because there just isn't enough ground clearance to do it from below. The capital costs to get ground-supported fans above the trees and the maintenance costs of operating them are likely much higher than just buying your own helicopter and training as a RW pilot. Given that, the farmer might as well rent the helicopter and RW pilot. I imagine a 10m fan mounted in a moving carriage, on a serpentine track supported by tall poles, and powered by electrified rails in the track. Then you'd need a shed for the working fan, the backup fan, and the repair parts, plus the generator and fuel storage. It would cost less than the helicopter to operate, but the capital costs seem like they'd be much higher, especially since every orchard block would essentially be a custom job, and helicopters can be factory-built. Maybe you could do double duty by also having a sprayer carriage that can use the same track?
FabHK 7y ago
Several reasons come to mind: The helicopter overcomes its own weight. So, a similarly effective ground based solution would have to push up so much air as to push into the ground with at least twice its weight (well, or be heavier than a heli). Might run a risk of getting stuck. Next, the heli rotor blades are above the tree line, where there are no branches and no trunk. A ground based solution would necessarily be between the trunks. You'd have to not only protect the rotating blades by ducting them, but also have a much harder time navigating. Finally, helicopters exist already and have other use cases. Ground based vehicle would have to be specifically designed and built, and would not be useful for much else.

by w-m 7y ago

Scoundreller 7y ago

It’s a time issue. The helicopter can quickly buzz a lot of more field than a tractor can.

maxerickson 7y ago

The helicopter is a 250 horsepower, 33 foot fan.

dsfyu404ed 7y ago
So 3hp/sqft (power/(area/time) would be better but we don't know how fast the chopper is moving while it blows the water away). That's not that much power. That's on the same order of magnitude as snow blowers Obviously not all hp are equal and you get into a discussion of cfm, specific impulse, etc, etc. but power/area should be a pretty ok proxy for drying power. It shouldn't be that hard to build something that looks like the bastard child of a concrete pumper and a pine mulch blower that can either fit in the bed of a pickup or runs off a tractor PTO and can apply more than enough airflow to destroy your crop if you use it wrong. Maybe include a big rubber hose (like those temporary water mains) on the vehicle to give the tree trunks a good whack as you drive by.
- maxerickson 7y ago
  I think I might try to make a contraption with a 33 foot fan that sort of hovered over the trees.

teh_klev 7y ago

> I wonder what the reason is for not having a ground-based solution. Running a small vehicle (lawnmower-size?) with a fan mounted on top I imagine the important part of the "drying" process/action is being able to give the branches a bloody good shake to dislodge the water droplets. It's likely that even very large fans aren't capable of moving that much air (compared to a helicopter's blades). Then there's also the question of even if you could trundle around the orchard with a set of fans able to push that much air I can imagine it would be comedically unstable and dangerous :) [edit: typo]

ehnto 7y ago
I wouldn't go anywhere near such a device. The amount of energy in a rapidly disembarking blade would be terrifying.
dsfyu404ed 7y ago
>I imagine the important part of the "drying" process/action is being able to give the branches a bloody good shake to dislodge the water droplets I imagine your typical 5-ish liter v8 coupled to a big centrifugal blower is more than capable of providing a "bloody good shake"

logfromblammo 7y ago

The article mentioned that smaller helicopters can't do the job because they don't move enough air. It likely has to be done from above because there just isn't enough ground clearance to do it from below. The capital costs to get ground-supported fans above the trees and the maintenance costs of operating them are likely much higher than just buying your own helicopter and training as a RW pilot. Given that, the farmer might as well rent the helicopter and RW pilot. I imagine a 10m fan mounted in a moving carriage, on a serpentine track supported by tall poles, and powered by electrified rails in the track. Then you'd need a shed for the working fan, the backup fan, and the repair parts, plus the generator and fuel storage. It would cost less than the helicopter to operate, but the capital costs seem like they'd be much higher, especially since every orchard block would essentially be a custom job, and helicopters can be factory-built. Maybe you could do double duty by also having a sprayer carriage that can use the same track?

FabHK 7y ago

Several reasons come to mind: The helicopter overcomes its own weight. So, a similarly effective ground based solution would have to push up so much air as to push into the ground with at least twice its weight (well, or be heavier than a heli). Might run a risk of getting stuck. Next, the heli rotor blades are above the tree line, where there are no branches and no trunk. A ground based solution would necessarily be between the trunks. You'd have to not only protect the rotating blades by ducting them, but also have a much harder time navigating. Finally, helicopters exist already and have other use cases. Ground based vehicle would have to be specifically designed and built, and would not be useful for much else.