Workhorse UFO™ Beats Competitor's Air Brakes By More Than A Coach Length

[DriVer]

For Immediate Release

Union City, November 28, 2006 -- The conventional wisdom is that the air brakes on a rear diesel pusher motor home can beat anything mechanical found on a gas-powered motor home. If you want the best in stopping power, that's the way to go.

This is among the assumptions the new Workhorse UFO™ chassis has just shattered. Test data indicates the Workhorse UFO™ HPB Quadraulic™ four-wheel anti-lock disc brakes are superior to the competition's air brakes.

Results from head to head tests performed at the Bosch Proving Grounds in South Bend, Ind., have been released by Workhorse Custom Chassis. They show the Workhorse UFO™ coming to a complete stop more than a coach length sooner from 60 mph than the competition's rear diesel pusher.

Here are the facts:

"¢ Coach on Workhorse UFO™ 26,000 lb. GVWR loaded to 26,000 lb.: Stopping distance, 60 mph to 0 mph, 189 feet.
"¢ Similar coach on competitor's 28,000 lb. GVWR rear diesel pusher with air brakes and loaded to 26,000 lbs.: Stopping distance, 60 mph to 0 mph, 238 feet.

<span class="ev_code_RED">Difference: Workhorse UFO™ stopped 49 feet sooner.</span>

"RVers driving big rigs want brakes they can trust to perform well in all kinds of weather and other conditions,"� said Bob Wert, Workhorse vice president of sales and marketing. "They haven't been mentioned much, but the stopping power and car-like touch of the Workhorse UFO™ brakes are some of the persuasive attributes for anyone who drives this chassis."�

Workhorse Custom Chassis

Workhorse Custom Chassis is ISO 9001 certified and a leader in the manufacture of chassis for motor homes, walk-in trucks and buses. It is a wholly owned subsidiary of International Truck and Engine Corporation. International produces IC brand school buses, school bus chassis, mid-range diesel engines, International brand medium and heavy trucks, and severe service vehicles. International also provides parts and service sold under the International® brand. Both Workhorse and International are subsidiaries of Navistar International Corporation (NYSE: NAV). For additional information call 877-294-6773 or visit Workhorse.com.

[DriVer]

For Immediate Release

Union City, November 28, 2006 -- The conventional wisdom is that the air brakes on a rear diesel pusher motor home can beat anything mechanical found on a gas-powered motor home. If you want the best in stopping power, that's the way to go.

This is among the assumptions the new Workhorse UFO™ chassis has just shattered. Test data indicates the Workhorse UFO™ HPB Quadraulic™ four-wheel anti-lock disc brakes are superior to the competition's air brakes.

Results from head to head tests performed at the Bosch Proving Grounds in South Bend, Ind., have been released by Workhorse Custom Chassis. They show the Workhorse UFO™ coming to a complete stop more than a coach length sooner from 60 mph than the competition's rear diesel pusher.

Here are the facts:

"¢ Coach on Workhorse UFO™ 26,000 lb. GVWR loaded to 26,000 lb.: Stopping distance, 60 mph to 0 mph, 189 feet.
"¢ Similar coach on competitor's 28,000 lb. GVWR rear diesel pusher with air brakes and loaded to 26,000 lbs.: Stopping distance, 60 mph to 0 mph, 238 feet.

<span class="ev_code_RED">Difference: Workhorse UFO™ stopped 49 feet sooner.</span>

"RVers driving big rigs want brakes they can trust to perform well in all kinds of weather and other conditions,"� said Bob Wert, Workhorse vice president of sales and marketing. "They haven't been mentioned much, but the stopping power and car-like touch of the Workhorse UFO™ brakes are some of the persuasive attributes for anyone who drives this chassis."�

Workhorse Custom Chassis

Workhorse Custom Chassis is ISO 9001 certified and a leader in the manufacture of chassis for motor homes, walk-in trucks and buses. It is a wholly owned subsidiary of International Truck and Engine Corporation. International produces IC brand school buses, school bus chassis, mid-range diesel engines, International brand medium and heavy trucks, and severe service vehicles. International also provides parts and service sold under the International® brand. Both Workhorse and International are subsidiaries of Navistar International Corporation (NYSE: NAV). For additional information call 877-294-6773 or visit Workhorse.com.

[Tom and Patty]

The Alpine's Peak Chassis has used 4 wheel hydraulic disc for that very reason since WRV built the first one. They do stop well

[The Shadow]

I wonder if they will do a test on a real steep downhill run where the exhaust brake does much of the work allowing the service brakes to remain cool. Then, when the discs in the UFO are glowing do the test comparison stops again.

Then, load up the UFO to 33,000 lbs like mine will take and do the same comparison tests once more.

Something makes me think they did a lot of picking and chosing as to what they wanted to report.

I wonder why they used a competitors DP? Have they taken their own RDP off the market. On their web site they make this statement when describing the RDP:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">With such a large vehicle we were sure to include full air brakes and a four-wheel anti-lock system to keep the coach in control while braking in slippery conditions. </div></BLOCKQUOTE>

I guess "such a large vehicle" is the key. The UFO is, after all, pretty small.

[smlranger]

OK, help me out here. In a real world situation if I need to pull my Explorer, 4,700 lbs, and need to stop, will the gas pusher with 4 wheel hydraulic disc brakes stop me as well as diesel coach with exhaust brake and air brakes? Now if that UFO has diesel and has exhaust brake, maybe the performance will be as good as or better than equivalent weight conventional DP with air brakes.

[edgray]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">will the gas pusher with 4 wheel hydraulic disc brakes stop me as well as diesel coach with exhaust brake and air brakes? </div></BLOCKQUOTE>
I believe the additional braking that will come from an exhaust brake would certainly help you stop quicker. I don't think you will get much disagreement there.

However, you seem to believe that the force of air pressure vs. hydralic pressure would make a difference. I'm thinking that braking ability will be more directly related to the SIZE of the surface area between the pads/shoes and the rotors/drums. I don't think it matters too much which medium is used to apply the pressure. I'm no physics major, but I believe air can be compressed and fluids cannot, therefore it would seem that air is "weaker" than fluid. At the pressures used for braking, it probably does not matter.

I do know that WCC calls their hydralic fluid applied brakes "quadralic" because they use four(4)pistons and a non-floating caliper. These four pistons push the pads towards both sides of the rotor. This provides a superior level of performance over the previous disc brake technology that used two pistons and a "floating" caliper, which pushed from one side and pulled the pads towards the rotor from the other side.

ED

[smlranger]

Ed:

No assumption on my part that air is better than hydraulic. I would think a good four pistion disc system would deliver excellent stopping power. If I was in the market for a gas rig, I would certainly give the UFO gas pusher a serious look. It would seem the UFO chassis with a diesel with exhaust brake plus the four wheel fluid disc brakes would be the better choice.

[Tom and Patty]

IMHO, I think the 49 feet come into play because of the fact that a hydraulic brake reacts faster than the air brake. Both systems are more than capable of locking up the rotors or drums. It is mostly the reaction time that covers the 49 feet, 1/2 second at 60 equals 44 feet.

http://www.rospa.com/roadsafety/advi...ck_braking.htm

"c" and "d" below were copied from the above link.

c) Hydraulic vs air brake systems
Cars use hydraulic braking systems but the pneumatic systems on LGV's creates an unavoidable time delay between brake pedal application and the transfer of air pressure to the brake units.

d) Drum vs disc brake systems
The favoured drums on LGV's, while suitable at lower speeds tend to fade and become less effective under sustained heavy braking.

[tderonne]

Ultimate braking force is simply determined by the force that can be generated by the tires. So once the brakes are "big" enough, nothing else really matters.

How long that maximum force can be generated, and how often, which comes down to how much heat can be absorbed and dissipated by the brakes, determines the overall performance.

Just some braking basics to remember...

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by dleslie125:
I wonder if they will do a test on a real steep downhill run where the exhaust brake does much of the work allowing the service brakes to remain cool. Then, when the discs in the UFO are glowing do the test comparison stops again. </div></BLOCKQUOTE>Given the terms of your post the UFO will also be using a transmission grade brake. (TGB)

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by smlranger:
OK, help me out here. In a real world situation if I need to pull my Explorer, 4,700 lbs, and need to stop, will the gas pusher with 4 wheel hydraulic disc brakes stop me as well as diesel coach with exhaust brake and air brakes? </div></BLOCKQUOTE>In real world terms the auxiliary brake system installed in the toad is tasked to stop the toad and not the tow vehicle. The TGB system in the UFO will assist in reducing the forward speed of the vehicle under all conditions where a down grade is involved.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tderonne:
Ultimate braking force is simply determined by the force that can be generated by the tires. So once the brakes are "big" enough, nothing else really matters. Just some braking basics to remember... </div></BLOCKQUOTE>The UFO uses the same 255/80 22.5 XRV tires just like most of the other RDPs out there in the 28K to 32K GVW range so that's pretty much a wash.

Forget what is known about conventional hydraulic brakes - UFO eclipses the previous braking technology with its HPB computer driven system. The driver applies the service brake and the Wabco computer determines the best and most expeditious way to stop the vehicle given the input from the driver.

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Meritor WABCO's Hydraulic Power Brake (HPB) is a braking and vehicle control system for business class trucks (classes 4 through 7) and buses that are equipped with hydraulic brakes. HPB provides:

<LI> Full power brake performance.
<LI> Braking control functions: Anti-Lock Braking (ABS), Automatic Traction Control (ATC) and Electronic Brake force Distribution (EBD).
<LI> Optional Parking Brake Control.

The HPB system has two main components:

<LI> Hydraulic compact unit (HCU) which consists of two independent electric motors driving two pump systems, two accumulators, a dual circuit fluid reservoir with integrated filters, pressure relief valves, solenoid valves and a dual circuit relay valve. The HCU is mounted to the vehicle frame rail.
<LI> Dual circuit master cylinder.

The HCU is activated each time the ignition is turned on, or whenever the driver steps on the brake pedal. If the system is equipped with the optional power park brake feature, the HCU supplies the energy to release and control the service and park brakes.

During normal operation, the ECU actuates two separate power drivers for the electric motors, keeping the pressure level within the desired limits.

When the brake pedal is applied, the master cylinder provides pressure equal to the pedal force. That pressure is sent from the accumulators to the appropriate brakes. When the pedal is released brake fluid returns from the brake calipers to the reservoir, and line pressure is reduced to zero.

For ABS, wheel pressure is individually modulated by eight integrated ABS solenoid valves in the ECU. For ATC, the normally closed ATC solenoid valve in the ECU is actuated and hydraulic energy is supplied to the sensed wheel. At the same time, the normally open ATC valve is actuated to prevent fluid flow back into the reservoir. The brake pressure is then modulated by the corresponding ABS solenoid valves.

For unparalleled stopping distance capabilities, combine HPB with the Meritor® Quadraulic™ hydraulic disc brake. Learn more about the Meritor® Quadraulic™ hydraulic disc brake.

Copyright ©2005 ArvinMeritor, Inc.

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Here is the complete documentation for the system.

Arvin Meritor WABCO HPB

This is a PDF file please wait while it loads.

[Jestme13]

Yada Yada Yada, does this senseles banter ever cease ?

I'm with 125 on this one, what happens in the stopping comparo when the DP guy hits the Jake, the UFO guy hits the tree I presume.

Youz guyz always making more outa sumptin den it reely iz.............

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jestme13:
... what happens in the stopping comparo when the DP guy hits the Jake, the UFO guy hits the tree I presume. </div></BLOCKQUOTE>The comparison was made vs a 28,000 RDP which it legitimately competes against. At 26,000 and yielding 2,000 pounds in GVW to the XC rail, the UFO is positioned to compete in this GVW range and to comparatively carry the same payload.

RDPs at 28K GVW do not have Jake Brakes however they may have exhaust brakes. The current gasoline powered UFO has a TGB which helps it slow down on grades and the system works effectively. This spring we might see where a UFO will have a trio of slowing/braking equipment consisting of the WABCO braking system, TGB "and" an exhaust brake using the ISB diesel engine option.

The WABCO computer system is a totally new braking system and unless you can set aside preconceptions about how hydraulic brakes work comparing the WABCO braking system to conventional air brakes in the context of this conversation is not possible.