Agricultural Aviation Technology

1
Agricultural Aviation Technology

• Dennis R. Gardisser, PhD, P.E.
• WRK of Arkansas
• Robert E. Wolf, PhD
• Kansas State University

2
Application Altitude

• High
• Low
• Window

3
Drift potential vs. Height Example
10ft 14 ft
4
Aircraft Boom Design

• Location relative to the wing
• Nozzle setup orientation on the boom
• Microfoil booms
• Positive action shutoff
• Boom suck back

5
Boom length/location
6
(No Transcript)
7
Distance below trailing edge of wing
8
ASABE Standard S572

• Explanation of Dv.1, Dv.5 or VMD, Dv.9, RS
  (Relative Span)
• Meaning of key words (Fine, Medium, etc.)
• Need to limit amount of small droplets or fines
• Practicality of regulation requiring 600 VMD
  droplet spectrum

9
Important Droplet Statistics
RS (Vd.9 Vd.1)/VMD
VMD (50)
Operational Area
VD0.9 (90)
VD0.1 (10)
10
Relative Span

• RS (Vd.9 Vd.1)/VMD

11
ASABE DSC and Volume Median Diameter (DV0.5) From
PMS Laser Spectrometer
Droplet Spectra Classification (DSC)
Droplet Size Range

• Very Fine (VF) lt 182µm
• Fine (F) 183-280µm
• Medium (M) 281-429µm
• Coarse (C) 430-531µm
• Very Coarse (VC) 532-655µm
• Extremely Coarse (XC) gt656µm

USDA ARS College Station, TX
12
Droplet Spectrum Generation

• Pressure effects
• Low pressure
• High pressure
• Aerodynamic effects
• Nozzle type effects
• Flat fan
• Deflector
• Sheet
• Disc Core
• Straight stream
• Electrostatic
• Rotary

13
Cutting Droplet Size in Half
Results in ?? Times the Number of Droplets

500 Microns
250 Microns
2 more droplets fill in the sphere
14
Air Temp 85F
Hot air goes which direction?
Canopy top 105F or more!
Canopy Floor 75F
15
Size

• 290/250 1.16
• 290 micron droplet is 16 larger than 250
• This may not appear to be a big change, but???

16
Droplet Data

• 250 v. 290 micron droplet
• Change in size?
• Change in Volume or Weight?

17
Volume or Weight

• Remember that this is a cube root relationship.
• If it was twice as big we would multiply
• 2 2 2 8 times heavier
• For 290/250 1.16
• 1.16 1.16 1.16 1.56
• Implies that a 290 micron droplet is 56 heavier
  than a 250!

18
0.125 orifice,300 deflector
Pressure Effects
19
0.125 orifice,50 deflector
Pressure Effects
20
300 deflector, 40psi
Orifice Size Effects
21
Use of models

• USDA
• AgDrift
• Australia

22
(No Transcript)
23
USDA Aerial Nozzle Atomization Models
24
Model Input Screen
25
Weather

• Wind Speed
• Wind Direction
• Relative Humidity
• Evaporation Potential
• Inversions

26
Recognizing Inversions

• Under clear to partly cloudy skies and light
  winds, a surface inversion can form as the sun
  sets.
• Under these conditions, a surface inversion will
  continue into the morning until the sun begins to
  heat the ground.

27
Strong Inversion
28
Courtesy George Ramsay, Dupont
29
(No Transcript)
30
Record Keeping

• Frequency
• Where to take measurements
• Usefulness of weather offsite (ie. Local
  airports)
• Utilization of smoke or other visual references

31
Flight Pattern

• Upwind
• Downwind
• Speed (Slow v. Fast)
• Helicopter v. Fixed wing

32
Surfactants

• Expected effects
• Potential to make the situation worse
• Clean out concerns

33
Desired Effect from Additives
VMD (50)
VD0.9 (90)
VD0.1 (10)
34
Actual Effect from Additives
VMD (50)
VD0.9 (90)
VD0.1 (10)
35
Air Temp 85F
Hot air goes which direction?
Canopy top 105F or more!
Canopy Floor 75F
36
Questions??