3. Why are Eagle aircraft tractors superior to other tractors for aircraft
towing?
Manufacturing– With 40 years manufacturing experience and continuous
product improvements. The TT series has 19+ years global in field service. This
is backed by unequalled reliability; which is reflected in the only standard
3-year/3,000 hr warranty.
All units Tier 3/Stage III A emissions standards. Tier 2 engines in stock.
All Wheel Drive (AWD) – The AWD power train of the Eagle TT-series provides
customers superior traction in all weather conditions. The TT series equal weight
distribution also provides more controlled steering at all angles.
Designed as Aircraft Tractors – Eagle aircraft tractors were designed from the
ground up specifically to move aircraft. Most other tractors in the industry were
designed to tow baggage or other GSE. Eagle Tugs designs its aircraft tractors
using precise Drawbar Pull (DBP) calculations and testing, assuring that its
aircraft tractors are rated correctly to move each load.
4. Aircraft Towing
Technical Brief
This Technical Brief explains the details behind the design features of Eagle TT
series which make them superior for aircraft towing:
Three Key Points provide a quality solution.
1. All Wheel Drive (AWD) vs. Rear Wheel Drive (RWD) – Discusses the
operational differences as they pertain to aircraft towing.
2. Drawbar Pull (DBP) – Discusses how drawbar pull is calculated and how it
applies to aircraft towing. The proper method to DBP testing is also
discussed.
3. Aircraft Tractor vs. Baggage Tractor – Discusses the operational
differences between an Eagle aircraft tractor and a baggage tractor, and
why Eagle aircraft tractors are the best option for aircraft towing.
5. All Wheel Drive (AWD)
vs.
Rear Wheel Drive (RWD)
Two major benefits of AWD aircraft tractors when moving aircraft:
1. AWD aircraft tractors provide superior traction on all surface conditions.
2. Equal weight distribution, no loss of steering with AWD aircraft tractors as
with RWD tractors which tend to be too light in the front end.
6. All Wheel Drive (AWD) vs. Rear Wheel Drive (RWD)
Proper weight distribution above a tow tractor’s drive wheels is calculated as follows:
RWD – Must have an equal amount of weight over the tractor’s drive wheels as the
required amount of Tractive Effort (TE) force. Also, in order to maintain effective steering,
the front steer-axle must weigh at least ½ the weight of the rear axle.
- A lineal pulling force of 8,800# TE multiplied by .9 COF = 8,000# DBP. So, in order to
develop 8,000 lbs. DBP, a RWD tractor must weigh 8,800# over its drive wheels (rear axle
only). Additionally, in order to maintain effective steering, the front steer-axle must then
weigh 4,400#. The result is that an 8000# DBP, RWD tractor must weigh 13,200#.
AWD – There must be an equal amount of weight over the tractor’s drive wheels as the
required amount of Tractive Effort (TE) force. However, an AWD tractor’s weight is
evenly distributed between the front and rear axles. Creating greater control forward
and reverse . As well an overall lighter tractor.
- An AWD aircraft tractor needs 8,800# over its drive wheels, since both axles are drive
axles, the total weight needed for an AWD aircraft tractor is 8,800#. Also, the weight to
maintain effective steering is also accomplished with ½ the tractor’s weight over front steer-
axle. The result is that an 8,000 DBP, AWD tractor must only weigh 8,800#, or 1/3
less than a RWD tractor generating the same DBP and greater control.
7. Many standard features and options
for the perfect solution.
Engineered for one purpose: Moving Aircraft Safely in all
Environments.
3 year/
3,000 hr
Warranty
Tier 3/Stage III A emissions standards, CE Compliance
8. All Wheel Drive (AWD) vs. Rear Wheel Drive (RWD)
Most importantly, proper weight distribution above a tow tractor’s drive and steer wheels
also assure proper, safe steering.
- Most RWD tractors do not demonstrate the necessary weight over the drive wheels, and
1/3 weight over the steered wheels, which at times may result in a lifting of the front
steered wheels, and a loss of traction. Even with proper weight distribution, pushing at
angles beyond 45 degrees with RWD tractors results in a right or left skid challenge,
caused by the doubled weight of the rear drive axle. Due to the fact that the rear drive axle
generates all of the Tractive Effort (TE), it tends to overpower the steering.
- AWD drive aircraft tractors exhibit none of the 2 wheel drive negative steering problems.
With equal weight distribution over front and rear drive wheels, AWD aircraft tractors
naturally overcome the resistance caused by turning an aircraft beyond 45 degrees.
Our tractors do not have a front end float when we push back as they have even weight
distribution.
9. Drawbar Pull (DBP) and Proper Testing
Strict calculations under standard towing practice is how we provide towing
capacities, by applying the SAE AIR 1316 specification to our Drawbar Pull (DBP)
calculations.
Eagle engineers calculate the true DBP capacity of our aircraft tractors and make
sure the towing capacity we market for our tractors is true in all weather conditions,
for all plausible surface grades, and for all potential weights of aircraft our tractor
move.
The testing method alone is crucial to determining a tow tractor’s actual
towing/pushing capacity. It has been observed that many manufacturers use a jerk
method which only demonstrates an immediate or one-time DBP capacity. They do
this because it can generate a higher rating by jerking the load cell one time, using
the inertia of the tractor to gain better results. This is not indicative of the tractor’s
towing capacity in a real-life situation in which the load, such as an aircraft, can not
be jerked forward or backward.
The Eagle Tugs’ testing protocol requires a gradual and consistent application of
power, while recording DBP, until wheel slip or torque converter stall is achieved,
indicating maximum DBP on that surface.
10. Drawbar Pull (DBP) and Proper Testing
The perfect solution based on strict engineering principles.
11. Drawbar Pull (DBP) and Proper Testing
DBP testing shall be smoothly accelerated without jumping and/or jerking
12. We are now halfway through this presentation.
3 year/
3,000 hr
Warranty
13. Aircraft Tractor Design
19 years ago, Eagle Tugs set out to design a better tow tractor specifically to move aircraft. The
only tractors in the industry at the time were general purpose tractors or baggage tractors.
The result of Eagle’s engineering is the AWD TT aircraft tractor (NSN 1740 01 461 4279). The
features of the TT-series that set it apart from its competition:
• AWD – The only AWD aircraft tractor in its weight class
• Low Profile – Designed to fit under the wings of most aircraft.
• Ergonomic Operation – Slide in and out design. No climbing.
• Visibility – Hitch Sight Tunnels allow the operator to see both hitches at all times.
• Reliable – The only tow tractor in the industry with a 3-year/3,000 hr warranty
"The TT-8 at Bagram is a life saver and tough as hell. The tractor is working well, just wish
we had it 10 years ago."
--Major George N. Christensen III, US Special Forces, 159th Aviation Regiment
14. Built Tough & User Friendly
3 year bumper to bumper warranty
15. Aircraft Tractor Design
Eagle AWD Aircraft Standard (Baggage) The Eagle Aircraft Tractor
Tractors Tractor Advantage
Only AWD tractors in Not required, too expensive AWD provides controlled traction
All Wheel Drive 4,000-12,000 lb DBP for pulling baggage on all surfaces/Lighter weight
Better for maneuvering around
Low Profile Only 38-48 in. tall 55-60 in. or taller aircraft. Less chance for accidental
damage to aircraft
Mid-operator, w/ low profile
Slide in and out, ergo Climb up and down, strain on
Ergonomics design operator
design, allows for easy
ingress/egress
Direct front/rear
No front hitch vision, must Direct operator visibility for safer,
Visibility hitch/nose wheel vision
use mirrors more efficient operation
through sight tunnels
Same size front and rear Large rear and small front Same size tires/Equal weight
Tire Size/Steering tires with equal weight tires, often too light in the distribution allow for controlled
distribution front end steering when moving aircraft
Cost competitive market, Proprietary power train component
Properly selected power
Reliability train relationships
must use lower cost relationship results in smooth
components operation and reliability
16. Baggage type tractors used in this weight class..
Lacking All Wheel Drive
Non ergonomic operators station
Reduced visibility due to height
Reduced front end control
No direct line of sight to hitches
Eagle Aircraft Tractor Design
Ex
ingre
Example of low profile design and direct
hitch view of the Eagle AWD TT-series
18. Eagle TT Series- Aircraft Tractor Key Features
3 Year /3,000 Hour Warranty
All Wheel Drive for controlled pushback in all weather conditions
Mirror-less hitch visibility (direct line of sight) front and rear hitches
Low-profile design under 47” for maximum visibility and safety
Ergonomic and safe “slide in and out bench seating”
Intuitive Automotive Controls (Mil standard 1472 human engineering)
40 year history of manufacturing quality Aircraft Tractors
Average unit produced in less than 30 days
Standardized replacement parts (NSN 1740 01 461 4279)
Custom paint options
23. Conclusion:
This Technical Brief explained the details behind the unique design features of
Eagle TT series aircraft tractors which make them superior for Aircraft Towing:
Three Key Points help us provide a quality solution.
1. All Wheel Drive (AWD) vs. Rear Wheel Drive (RWD)
A. TT-series provides customers superior traction in all weather conditions.
The TT series equal weight distribution also provides more controlled
steering at all angles.
2. Drawbar Pull (DBP) –
A. Strict testing with SAE AIR 1316 regulations under normal operating
conditions of an aircraft “NO JERK TESTING.”
3. Aircraft Tractor engineering not a Baggage Tractor
A. Engineered to move aircraft smoothly and safely.
B. High quality, and durable backed by a 3 year/ 3,000 hour bumper to
bumper warranty.
24. Presented by:
Justin Akinleye – Director- International Business
Eagle Tugs constantly strive to improve our products and simplify maintence.
Please refer to the updated specification sheet for current specification.
Manufactured in Greater Detroit:
Eagle Tugs
26111 Northline Rd
Taylor, MI 48180
USA
Global Sales Office the United Kingdom:
Eagle Tugs
Maple House
High Street
Potters Bar
Herts, EN6 5BS
UK
Agents globally.
www.eagletugs.com
