Wanderlodge Gurus - The Member Funded Wanderlodge Forum - David's Musings

WanderlodgGurus online for another year.

Sat, 17 Jun 2017 23:45:20 +0000

Folks,

We're online for another year. I just made the whopping $35.00 payment today! That's $2.92 per month for our webhosting at HostUS. Add to this $12.00 per year for our domain name registration and you have the total cost of the forum! Thanks everyone! Enjoy!

Forum Down Time

Wed, 22 Mar 2017 20:05:47 +0000

I'm in the process of adding some features which required an upgrade of some of our software components. The components are loaded. You shouldn't see any difference in the forum's function. If you do please let me know. Thanks!

Bus Stopping Power

Tue, 14 Jun 2016 16:59:40 +0000

Hi Guys,

Attached is a good paper on Bus and Truck stopping distances using drum and disc brakes. They look at a fully loaded class 8 truck, loaded to GVWR, and a fully loaded School Bus. Interesting that both are capable of locking their wheels on a high grip surface, and the bus outperforms the truck in stopping distances. Of course, disc brakes outperform drum. Amazing that the school bus is able to achieve over 0.70 g's of stopping deceleration and distances as short as 180' from 60 mph. Turns out that buses can stop pretty well after all, just stand on that pedal and keep your eyes on the road.

Truck Bus Brake Performance.pdf (Size: 3.4 MB / Downloads: 3332)

Privacy, Google, and Web Browsers

Mon, 09 Mar 2015 14:51:27 +0000

I've been finding it more and more disturbing that after I Google something I'm often inundated with spam emails from vendors wanting to sell me the same or a related item. I find it really creepy. We all know that Google sells adwords and from the beginning they stored our search strings to help sell their adwords, but lately they've taken it a step further. Now it seems they're storing our search histories along with IP addresses, email addresses, and other personal identifiers so that advertising can be directed to a specific user. Of course all this stored information is available to whoever buys it or subpoenas it. This is made worse by running Chrome on our PC's. With Chrome Google has the ability to write and read data directly to and from our machines. So, I deleted Chrome from all my machines and I'm weaning myself off Google. There are other viable alternatives which sprang up specifically to address these privacy issues. I'm now running Pale Moon as my web browser and I tend to use DuckDuckGo for my search engine. Both have very appealing privacy policies of not collecting and storing search histories along with associated users IP addresses and other persona ID information. I'm fed up with Google building a profile of every user, selling it to advertisers, or giving it to the NSA. The Google feature I miss most is, "Do no evil"!

Rally Table mover

Sat, 18 Oct 2014 16:17:50 +0000

Not that this is a machine most people want or need. It is rv related and one that helps promote Fellowship. Tim and I usually get to a rally a night or two early to set up. One of the important venue attributes is pick-nick tables at each rv site. We need to get the tables away from the sites when the non rally leaving rv'ers depart and before the arriving rally rvers notice the sites came with tables but theirs is missing.
Volunteers are plentiful but with 50 to 70 tables to move, it is just too much to ask. RV park staff offer help but with the rally influx they are never able to get it done in the time limits we set.
This is the second style I built. it is a slip on non clamping wheel set that will carry two table. the second table is tilted ontop after the bottom table is mounted on the wheels.
The one issue we have is the need to lift the table to slide the wheel under. It is a bit awkward and can be too heavy for one person with some woods used for table construction

20140930_114413[1].jpg (Size: 1.7 MB / Downloads: 884)

Audio Monitor

Thu, 16 Oct 2014 16:31:30 +0000

David, I know that this forum category is your blog but wanted to start you on an idea I keep coming back to.
I was reviewing 5 ton trucks at auction for my gijeep.com site and ended up buying a bunch of recoding equipment. cant call it high tec because I bet there are phone apps that can do the same listening and making a graphical or digital file of sound.

My idea is to build a listening device for the bus engine compartment and the towe'd cabin and tow'ed engine compartment. that device makes a record of the sounds in real time and compares the sounds to a file proven to be recorded during normal operation. All done in real time so the operator can puhs the equipment to the limit and back off or stop when issues arise.

Temp gauges we now use are much like a audio graphical display would be. Idiot lights we now use compare input to a normal threshold and are much like a display warning of abnormal sound would be.

sitting in my tractor I can hear issues and some of the sounds are even enhanced when I use ear phones which makes me wonder if there are clues that I miss by not being able to hear all the noise and being able to remember all that is normal.

back on Ernie's forum around 2006 there was a poster looking for a audio file of an 8v92. That got me wondering why he needed it. I think he was just nuts about sound? maybe not.

SpongeBob's Power Management System

Fri, 10 Oct 2014 23:39:49 +0000

All the magic happens in what Vantare calls the Bay Interface Module (BIM). The BIM is probably the most complex portion of the conversion's electrics. It allows remote control of the 120VAC motorized circuit breakers in the Main Distribution Panel (breaker box). A momentary push button switch panel upstairs in the living quarters lets the user select which loads are on or off. Pushing a switch sends a signal to the BIM instructing the BIM to change the state of the circuit breaker.

To accomplish this Vantare used a product developed by Square D called Powerlink AS. The unfortunate part is that Powerlink AS has been superseded by Powerlink G3 which will soon be superseded by G4... Sigh! (This only proves to me that it's wise to be able to debug and support the AS version rather than chase newer products that seem to have very short lifetimes). Fortunately, there are many NOS parts available for the AS; furthermore, I'm told that the system is very reliable but having a couple spare 15, 20, and 30A motorized circuit breakers on hand seems prudent.

The breaker box houses the Powerlink AS Programmable Interface Module (PIM) which is essentially a programmable controller. The PIM uses a low voltage bus to control each motorized circuit breaker. It does this by receiving Square D Sy/Max commands over an RS232 or RS485 bus. (I'm sure you recall the age old and venerable RS232 and RS485 protocols). Sy/Max is Square D's communication protocol.

The Bay Interface Module receives a signal from the upstairs switch panel, it decodes the signal and translates it into a Sy/Max command and sends it out it's RS485 interface to the Powerlink Programmable Interface Module (PIM). The PIM then signals the motorized circuit breakers to make a change in state. The Bay Interface Module also drives the LEDs at the user switch panel: Green - circuit energized; Red - circuit deenergized; Blinking - load automatically pruned by the Automatic Power Management System.

The Automatic Power Management System is simplicity onto itself. It looks for available shore or generator power. If neither is available it sends a "phase-loss" signal to the PIM and the PIM uses it's internally pre-programmed configuration to prune off pre-configured loads preventing inverter breaker tripping. As far as I can tell, all configuration and circuit breaker state is stored in the PIM and it's fully programmable meaning that I can choose which loads get pruned.

So, the system uses two discrete components from Square-D, the Powerlink AS PIM and the 15/20/30 amp motorized circuit breakers. Vantare then homebuilt their control circuitry implementing Square D's Sy/Max protocol to drive the PIM and to drive the user switch panel LEDs and interface with the switch panel momentary buttons. The Power Management System is gotten virtually for free from the PIM. The BIM contains circa 2000 componentry. I really think that if I should have any issue with the Vantare portion, much of it can be replaced by an Arduino or similar single board computer, which would be a lot of fun!

Here's a pic of the Powerlink PIM (A) in the pic and how it bolts cleanly into the panel box:

Powerlink AS PIM.JPG (Size: 45.6 KB / Downloads: 1371)

Out 'n About in Mr. SquarePants

Tue, 12 Aug 2014 15:05:03 +0000

We've been traveling in Mr SquarePants for the past month. First a trip to Harrisburg Pa, then a little sightseeing in Nasheville TN, followed by a Prevost Service in Goodlettesville, TN. All's well! The family has really grown into this new bus. Sleeping's a cinch, everyone's discovered their favorite cubbyholes, and try as she might, Suzana has yet to overflow the basement storage. Ha! LOL!

So far this year I've driven 6000 miles. I'm still learning, and probably will be for quite some time, but I've really gotten to know this machine. I thought I'd give you an update on what I've learned so far.

First, backing up took some getting used to. It's not like a BB where you can hang your head out the captain's window, not unless your head is smaller than my 4"x6" toll booth window! So I've had to relearn backing up with only sideview mirrors and my review camera. I got it down now, but it was dicey in the beginning. The bus is longer, but it has a shorter rear overhang, and it turns sharper, so I've really gotten the hang of placing the rear axle, judging the overhang, and cranking the steer tires. SpongeBob has a liftable tag via an air bag linkage. This feature really tightens up the turning radius. It's also very fast, as quick as I can throw the lever, the tag is up. Well it's not really up, just unloaded. If the bus wasn't close to 35,000 lbs on the drive/tag it would be up!

There are no leveling jacks on SpongeBob; instead, I rely on Prevost's Level-Lo feature which is a fancy word for air leveling. I can use Level-Lo to automatically level the bus, or I can do it manually. This feature also allows me to raise or lower any portion of the bus to clear obstacles. It works well and it eliminates a piece of complexity. Typically I pull into a CG and while the engine's running on fast idle I put Level-Lo in automatic mode and within a few seconds the bus is level and ready for slideout deployment.

The slides on SpongeBob are non-structural. It's interesting that the first generation of Prevost slides were structural. (Many of you have probably seen the six large diameter locking pins, three on each side. Prevost tried that setup for maybe 3 generations of slides but you'll notice that as of the '07 chassis they went to a non-structural slide with a single locking pin mounted at the center and bottom of the slide body. They also modified the chassis structure to restore strength. Featherlite Vantare adopted the non-structural slides from the very beginning. I have two locking pins at the top and a huge amount of steel (beams) in the sidewall and basement to restore strength. I have no pressurized air seals; instead, I have bulb style compression seals, which eliminate another source of complexity. I couldn't be happier with my slideout design and implementation - smooth, quiet, dry, and reliable operation.

The dual Trace SW (4KW, pure sinewave) inverters provide all the power to the coach, even when plugged into shore or generator power. Everything comes thru the SW's. There are no additional transfer switches or contactors upstream or downstream. Yet another source of complexity eliminated. The SW's incorporate an automatic generator start feature. No third party GenCon overseeing battery voltage and genny start. (another source of complexity eliminated). There's no battery dedicated to start the generator. I have a switch that allows me to connect the starter to either the house batteries or the chassis batteries. I have eight 4D AGM's and am pleased with their performance. Without Cruisair's running, but with ordinary use of all other systems including my 120VAC Jenn Air residential refrigerator, I can go 60 hours before the generator automatically starts.

My slideout's are electric motor driven as are the lock pins. My toilet is by Headhunter and is macerating via a jet of water, no air power. Pocket doors are electric motor driven. Dump valves are electric. I have an air accessory system but the only house items on it are the captain's air seat, a lock for the telescoping and swiveling steering wheel, and a slide out floor for the entry way. There's no entryway air door lock. My accessory air pressure system stays pressurized - it doesn't leak down. In fact Prevost owners are usually taught to run the engine at low idle for a couple of minutes prior to switching to fast idle. They do this to build air pressure in the accessory air system. Why? Because the belt driven engine cooling fan uses an air bag tensioning system to snug up the three parallel v-belts. Switching to high idle before the system is snug can sometimes throw a belt. Me... I throw it to high idle as soon as I see oil pressure, usually within seconds. This lack of interior air driven components (pocket doors, slide seals, toilets, etc), means I never run my aux air compressor. There's no need!

It's a complex bus with many complex components, but the elimination of hydraulically powered components, air powered components, and third party control devices like GenCon's, and not relying upon slide body's for structural support which eliminates jammed and sticking lock pins, is proving to me that Vantare has added simplicity where it counts. All this adds up to reliability.

The most challenging aspect of the bus is it's height. He measures 12' 4" at the top of the Gerard awnings, but then I have have a KVH dome that pushes me to 13' 5" at the center of the bus. The top has little on it that requires service - my four Cruisairs are in the basement, but I have learned that you can walk on a Prevost roof, and you can walk anywhere on the roof, not just at the roof bows.

So far we're getting a real kick out of this machine and I just wanted to share some of it with you.

Tracking Down Vibrations

Sat, 05 Jul 2014 01:33:45 +0000

A smart phone can sometimes be used to track down vibrations. Download one of the vibration analyzer apps, I use "FFT Vibration Analyzer" on my Android. This tool will give you a graph of vibration frequencies versus amplitude. Our tires rotate at approximately 500 rotations per minute at 60 mph, or 8 Hz. Assuming a sixth gear ratio of 0.639 and a final drive of 4.56, we can calculate the following approximate fundamental frequecies for tire, driveshaft, and engine vibrations at 60 mph:

Tire: 8 Hz

Drive Shaft: 8 (tire Hz) * 4.56 (final drive ratio) = 36 Hz

S60 Engine: 1450 (engine rpm) / 60 / 2 * 6 (number of cylinders) = 72 Hz

8V Engine: 1450 (engine rpm) / 60 * 8 (number of cylinders) = 190 Hz

Of course it's not as simple as it sounds because each of the vibration sources will generate harmonics at multiples of their fundamental frequencies; however, the fundamental is the highest amplitude.

Ride Height and Ride Quality and Ridewell

Fri, 18 Oct 2013 15:24:40 +0000

I find myself thinking about something Bennie Collier told me a long time ago. He said the LXi rides better when the steer axle ride height is set lower than the drive axle's.

When setting the axle ride height I've always blindly followed Ridewell's recommendation of 8" +-3/16" at both the steer and the drive axles. This seems reasonable because both axles use essentially the same air springs. The air spring part numbers are different but that's mostly because of differences in the air fitting location and mounting bolt holes. The bellows and the pistons are the same parts on both the steer and the drive axles, so I've always set my ride height to their recommendation, basically 8 inches.

We often talk about the Blue Bird Bounce or as some call it, Porpoising. We all know what it is because it's something all Ridewell suspension equipped Wanderlodges do.

The technical term for Porpoising is Pitch. Pitch is vertical displacement of the bus body on it's suspension but in opposite directions at each end. The front goes down while the rear goes up. At some point between the axles there's no up or down movement, that point is the pitch axis.

It turns out that pitch isn't dependent on the center of gravity location or the suspension geometry, it's dependent on the spring rates at the drive and steer axles.

Imagine an extraordinarily stiff drive axle suspension and a soft steer axle suspension. In pitch all of the motion will be at the steer axle and the pitch axis would be the drive axle. Alternately, we can imagine a stiff steer axle and a soft drive axle, now the pitch axis will be the steer axle and all the vertical motion would happen at the drive axle.

Without having "yet" done any experiments, I think our pitch axis is way back close to the drive axle. After all, the springs are stiff on the drive axle as compared to the steer axle. The effect of this is a lot of vertical motion at the steer axle as we all feel through our captains seats.

What does this have to do with Bennie's advice? Well lowering the steer axle ride height has the effect of stiffening the air spring. Now we've moved the pitch axis forward. In theory, we've reduced the vertical motion felt through the captain's seat.

Remember, this is all theory - I haven't yet experimented but I will! I'm going to play around with lowering the front in very small amounts followed by test drives. I seem to recall Bennie suggesting 3/4ths of an inch. I wouldn't go any more than that. In conjunction we could raise the rear slightly to soften it.

An Experiment without Shocks

Wed, 02 Oct 2013 13:02:16 +0000

I removed my steer axle Koni shocks and drove around the block. Actually, I had a pair of worn out Koni 90-2497SP1's which I drained of the damping oil and I bolted them on. I didn't want to drive without shocks because it's the shock that limits rebound travel.

What I found is that the bus body wildly oscillated at it's fundamental (resonant) frequency at even the slightest pavement input. Speeds had to be kept down to keep the bus drive-able, less than 40 mph. I counted the number of oscillations in a 10s period and found my bus has a resonant frequency of approximately 1.3 Hz.

Any abrupt, small amplitude road imperfection like a manhole cover or a slight change in road elevation caused the axle to tramp. This motion was around 10 Hz which is the resonant frequency we'd expect from a tire.

From the bus body frequency of 1.3Hz I can calculate the spring rate of my air springs: Res Freq = 1/2pi * sqrt (K/m)

(K)'s the spring rate and (m) is the sprung mass on the steer axle. This formula calculates to 2180 lbs/in, but there are four springs so each spring is providing 545 lbs/in.

I think a resonant frequency of 1.3 Hz is on the high side, and a spring rate of 2180 lbs/in is a smidge stiff. Most luxury passenger cars are around 1 Hz and most performance cars are around 2 Hz. I have some Prevost air spring documentation which shows that they're achieving 1 to 1.1 Hz, or a 4 spring equivalent of 322 lb/in per spring, almost half of my LXi.

The shock can make the suspension overly stiff by not allowing sufficient time for rebound. This forces the suspension to be slightly compressed when it hits the next bump. Compressed means it's operating in higher range on the spring rate curve. (Air springs are very progressive).

Driving without shocks taught me just how necessary they are on our buses. The bus floated over bridge abutments and manhole covers which was good, but the body oscillated wildly and the axle tramped badly. I realized just how good the Koni's are even on their softest setting. I set mine to the softest setting and drove 135 miles from Charlotte to Asheville NC. The softest setting is actually quite a bit of damping compared to no shocks and it allows the suspension time to rebound for the next bump. I have a whole new appreciation for how hard the shocks work and how important they are!

For a long time I thought the optimal setting was 1 turn from full soft; I like full soft better!

Why cheap shocks might be better

Thu, 26 Sep 2013 16:21:39 +0000

There's an interesting graph in "The Shock Absorber Handbook", by Jason Dixon. I uploaded a copy to our Library at Document Library -> Theory.

Here's a snippet of the graph:
Bus Ride Quality Transmissibilty.JPG (Size: 95.45 KB / Downloads: 1314)

Transmissibility is the degree to which road imperfections are transmitted thru the suspension to the body of the bus, the seats, and the occupants. It's a measure of how the suspension system reacts or overreacts to road input. If you bounce the suspension at it's natural frequency then the bus will theoretically bounce out of control (frequency ratio 1 on the chart). For our buses the natural frequency is around 1 Hz.

Looking at the graph you can see that there's a range of frequencies where shock absorbers actually make the ride worse. We'd be better off without them. The transition is where the graph transmissibility passes thru 1. This occurs at sqrt(2) times the resonant frequency of our suspension. For all road inputs above this frequency we'd be better off tossing our shocks!

This means for any road imperfection that comes at us faster than seven tenths of a second (1/(sqrt2*resFreq)) we'd have a better ride without dampers! So for every pothole, bridge abutment, railroad track out there, your ride would improve if you removed the shock.

So how do cheap shocks make the ride better? The road imperfections listed above are all low amplitude motions and there's a correlation between low amplitude road disturbances and frequency - low amplitude equals high frequency and we've already said that high frequency ride is better w/o shocks. Cheap shocks are only speed sensitive; they're not frequency sensitive, so you'd expect them to be worse on these types of road inputs. But wait - cheap shocks also come with cheap bushings. They're overly soft and overly compliant. This is the key to providing a good ride over choppy surfaces. The soft and compliant bushings deflect on the choppy surfaces and act closer to no shock at all! The cheap shock acts as a poor man's frequency sensitive damper.

Incidentally, the Koni Frequency Sensitive Damper (FSD) does just this. It has special valving that provides maximum damping for large amplitude road inputs and minimum damping for small amplitude road surfaces. This way slow resonant frequency road inputs won't bounce us out of control, while sharp and fast disturbances are minimally damped.

Koni offers FSD's for our wanderlodges but only for the drive and tag axle, so if you want a good ride on rough road, take your adjustable Koni steer axle shocks and back the stiffness off or put in some soft bushings. Air springs by nature have built in damping so there's little to lose and much to gain.

Anti Sway Bars 101 (LXi and LX)

Tue, 27 Aug 2013 14:01:07 +0000

We've had many discussions on this forum and on other forums about the anti-sway bars used on LXi wanderlodges.

There's a few things that bear mentioning.

1) just like air springs, the sway bar acts thru the tires. This means that we need to look at forces at the wheel, or wheel rates.

Our beloved Ridewell stick axle steer suspensions have a motion ratio of about 1/2; that is, for a 1 inch motion at the wheel the air springs are compressed 1/2 an inch. Likewise, for a 1 inch motion at the wheel, the sway bar is deflected 1/2 of an inch.

2) there's a characteristic of suspensions called "roll stiffness".

If you lean on the top corner of the bus, up by the goat rails, the bus will roll over slightly on it's lengthwise axis. The degree to which the bus tries to remain upright (vertical) is roll stiffness and it's measured in torque per degree of rotation, or ft-lb/deg.

3) the bus chassis itself has a resistance to twist called "torsional stiffness" which is also measured in torque per degree, or ft-lb/deg.

A while back when I was doing my Finite Element Analysis on Woody's slideout conversion I discovered that our Wanderodges have a torsional stiffness of around 12000 to 15000 ft-lb/deg.

4) as the anti-sway bar does it's job it twists the bus chassis.

The job of the sway bar is to keep the steer axle parallel to the bus chassis; that is, it resists with it's spring force any rotation of the bus body relative to the steer axle. To do this the sway bar applies a countering torque to the bus body. This means that any sway bar deflection will result in bus body deflection in the twisting sense (think wringing out a bath wash cloth).

The question then is how much bus body twist should be allowable for a given anti-sway bar twist? If both the bus body's and the sway bar's torsional stiffness is 15000 ft/lb per deg, then for every degree rotation of the bar you'd have one degree of twist in the bus chassis. This isn't good. This kind of bus body twisting will wreak havoc with suspension geometries, ride quality, handling, and wear and tear on the bus body and interior components. A reasonable maximum for anti-sway bar torsional stiffness as a percentage of bus body torsional stiffness is 10%. This means that if the sway bar twists 1 degree the forces transmitted into the bus body result in a twist of only 1/10 of a degree.

If our bus body has a torsional stiffness of 15000 ft/lb per degree, then we need to limit our suspension's torsional stiffness (acting thru the wheels) to 1/10th of that or 1500 ft/lb per degree.

So what's wrong with the sway bar used in the LXi, well it has a torsional stiffness at the wheels of around 1200 ft-lb per degree. Couple this with the 1200 ft-lb/deg of torsional stiffness from the air springs brings us to a total torsional spring rate of 2400 ft-lb/deg or roughly 16% of the bus body's torsional resistance.

In short, the anti-sway bar adds excessive roll resistance such that the bus body is being twisted like wringing out a towel.

Have your toad push your motorhome (grade assist)

Sun, 18 Aug 2013 14:10:50 +0000

This is a topic that comes up every now and then. Its feasibility has always been quickly dismissed. This morning I took a couple minutes to scratch on the back of an envelop. Here's what I found:

A common argument against PUSH (or toad assist on grades) is that the typical tow bar isn't designed for it. Everyone knows that tow bars are designed for towing and not pushing. (Here I don't say anything about any particular bar. I simply draw some generic conclusions that can be applied to any bar).

One of the forces that tow bars need to resist is braking. When the bus driver applies his brakes the toad is forced up against the bus. In effect and in the absence of toad auxiliary braking the toad is pushing the bus.

A typical bus should be able to stop from 60 mph in 200 ft. This equates to a deceleration rate of (Deceleration = VelocityInitial**2/(2*Distance)), or 20 feet per second squared.

I chose the toad weight to be 5000 lbs which seems to be a good estimate for the average toad.

As the bus decelerates the toad exerts a force on the bus thru the tow bar. With a toad weight of 5000 lbs and a deceleration rate of 20 feet/sq sec, the force the toad applies to the bus is (Force = mass*deceleration) or 3060 lbs. So in fact, the tow bar needs to be designed to handle significant forces under panic braking.

Now, with my 2002 LXi I know that I require 500 HP to climb a 6% grade at 50 mph. Remember that not all of my crankshaft horsepower is applied to the wheels; there are losses along the way and those losses are typically in the range of 20 to 30%. Let's assume that 75% (or .75*500 = 375 HP) of the crankshaft HP appears at the wheel.

Let's see what kind of horsepower the toad is exerting on the bus during panic braking.

The formula to convert tractive force to horsepower is P = F*S/375 where F is the force exerted by the toad, S is the speed at which the force is exerted, and P is horsepower. Substituting in F=3060 lb, S=50 mph we get 408 HP. Notice how this number meshes well with my 375 HP prediction based on experience. Also notice that we're not applying more force to the tow bar than what would normally occur in an extreme stop.

It's likely that your toad isn't capable of 400 HP at the wheels. It may be that you're only capable of 200 wheel HP. This reduction in HP and it's associated reduction in tractive force means that you'll be applying even less force to the tow bar than what it will see in a panic stop.

What this quick back-of-the-envelop shows is that there's promise in PUSH assist.

Disclaimer: This is a simple physics brainteaser and is far from exhaustive. Lots of real world corrections, factors, and safety practices need to be addressed. I don't recommend anyone push their motorhome due to these issues. In addition there are State laws and DOT statutes to comply with. What this simple analysis shows is that as a campfire discussion the idea can be kicked around some more!

My bus is a green machine!

Mon, 12 Aug 2013 23:40:34 +0000

I was reading an article today about air travel. Turns out that a non-stop flight from New York City to San Francisco, flying coach, costs 2.23 tons of carbon dioxide per passenger.

The same 3000 mile trip in my bus costs 4.8 tons of carbon dioxide; for my family of five that comes out to about a ton of carbon dioxide per passenger.

If I were to do the same trip in my Toyota Sequoia loaded with 5 passengers and all our luggage it would cost roughly 1.6 tons of carbon dioxide or one third a ton of carbon dioxide per passenger, but it'd be tough to keep our sanity for the full trip duration.

Assuming we do keep our sanity and do make the 6 day journey I have to add in the carbon foot print of 5 nights of hotel stays and 3 restaurant stops per day along the way which adds approximately 500 lbs of carbon dioxide to the trip which bumps the per passenger amount up to around 0.37 tons of carbon dioxide.

Bottom line, my bus is a green machine! Yeah right!

Gravity works

Sat, 06 Apr 2013 02:37:14 +0000

Anyone ever heard of droop? Okay, stop looking in the mirror - not that kind of droop!

Ever wonder why truckers drive the way they do? One minute they're on your tail next minute your passing them like they're standing still.

Well, it turns out this is by design. See, a good trucker or more correctly a trucker who can't pass fuel surcharges off to an unsuspecting public knows how to conserve fuel. He also knows how to get a million miles out of his engine.

A good trucker plays a perpetual motion game. This kinda game works well on the right side of this country (east of the Mississippi).

What a good trucker does is let gravity work for him. The hills are rolling so he's not afraid of running out of brake before the next up hill. He lets his speed build on the downhill and he aids it if necessary with added boost. As he progresses thru the depths of the valley his speeds may reach 70 mph and his turbo is freewheeling. He's building his momentum.

As Sir Isaac Newton taught us, momentum is conserved. The momentum built coming down the hill is given back when climbing the hill. Well, not completely given back or we'd have a perpetual motion machine and God would never allow that or we may become Gods ourselves!

So we have this head of steam coming down the hill. As the next hill approaches he lets this gift of nature propel him up. Now he feathers the boost to get the most out of his gift. He lets his speed drop slowly as he dials in more boost, but he's careful to maximize his gift. He doesn't want to peg the boost and loose all his advantage, and why waste fuel fighting air, so he lets his speed diminish to 65, then 60, then 55 where rolling resistance exceeds air resistance, then he feathers on the boost. As the crest approaches he completely backs off letting his momentum propel him over.

He dances a delicate dance. Time and again he trades off a thirsty steady speed for a frugal undulating one. Like a pendulum he swings from peak to peak letting gravity return to him a portion of the fuel he burned to make the next peak.

So, how is this related to droop? Well, turns out our cruise controls are fuel burners. If you want to save a half mile per gallon then you need to get off the cruise and drive the bus. The problem with our cruise control is that it wants to always maintain a constant speed. If you also have the jake on then it's a double whammy. That gift of nature is wasted and is being turned into global warming.

See, our cruise controls are too good. They dial in full boost at the slightest decrease in speed. If we know that we're close to cresting the hill, and we know that momentum will provide us a free ride, then we don't need full boost.

Droop is a DDEC parameter. It's the number of rpm's that the DDEC will allow the engine to fall before full boost is applied. It's programmable and your local Detroit Diesel Allison Service Center can change it for you. This modification will allow you to use cruise control to drive the hills like a good trucker without the attentiveness required. But, if you really want to do it right and gain half a mile per gallon, turn off the cruise

Two Bus CLub

Mon, 01 Apr 2013 16:38:41 +0000

Folks,

I've owned my LXi for quite some time, but as many of you know I've really been on the lookout for a bus with bunk beds. Our problem has been sleeping arrangements in the LXi. We can make things work, but I never really look forward to pulling the couch out and inflating the air matress for our 3 little ones (ages 2, 3, and 6). The morning chore is a reverse of this. Folding the sheets, deflating and stowing the air mattress, and folding up the sofa bed.

I couldn't believe it when on this trip to Harrisburg Pa to visit my family that my neighbor mentioned their Prevost. Well actually it's there son's prevost. He's been in the music business for years and wanted something for his growing family. They had Marathon take an entertainer coach and convert it for motorhome use. It has the full complement of features that we've all grown accustomed to but it also has not only two bunks but three bunk beds.

Suzana is the goddess of the interior so I knew a final decision rested with her, and of course I thought it would be hopeless. So we got together with my neighbor for a showing of the Prevost. Wow! Suzana loved it. My wife is very much into earth tones and not too much glitz - she values functionality. This bus has it all. We've all seen late model Marathon interiors and this one measures up in every way. It's a laminate interior but in a ribboned wood veneer. The floors are a combination of wood planks and granite. It has two slides so there's a king size bed in the bedroom and lots of room for a family of five. The bunk beds are nestled in and don't seem to take away from the floor plan. Exquisite craftsmanship everywhere.

The systems played to everything I'd ever need in a motorhome. Two 36" flatpanel TV's, rfMogul satellite dish, ipad controlled crestron, 8 8D batteries, 8KW of true sinewave inverters, large holding tanks with a headhunter freshwater pump. The list goes on and on. Then the exterior, again earth tones in a not too showy paint, airbrushed as has been Marathons style over the past 5 years.

The coach is a late model 2007 so it has Prevosts latest slide mechanicals. This type has the single locking pin coming up from the basement area. It also has the latest chassis upgrades with the new Prevost-Beam configuration which I think might be the best motorhome chassis in the world.

Well against my better judgement we went for a test drive and it blew me away! I've driven p-buses before but nothing like this. Prevost has really upped their game in the ride and handling department. It has traction control and active air bags, it has a active steering which helps in moose maneuvers. It even has a radar transmitter mounted up front that will automatically engage the brakes if it thinks we're closing in on traffic or other obstacles.

Needless to say, I'm now a member of the two bus club so I'll be putting my LXi on the market shortly. Also, I'll need to sell my LXi rapidly so I'm going to list it at a low price, sorry to all of you LXi owners, but I have to do it. I apologize for bringing the market price down so drastically with the sale of my LXi, but I'm sure you'll understand, plus with a little bit of effort I'm sure you'll be able to sell yours for a little over my rock bottom price. Trust me, it'll work out.

Anyway, wish me luck!!!!!!!!!!!!!!!!

APRIL FOOLS

Filter Minders for Dummies

Wed, 20 Mar 2013 14:29:50 +0000

Folks, a friend asked me about the Filter Minder and it's suitability as an intake plenum diagnostic tool. One such use would be in determining whether the LXi's DD Series-60 has an overly restrictive fresh air intake system.

The Filter Minder (FM) is a device that measures intake restriction and potentially indicates the need for air filter replacement.

The FM has 5 predetermined click off points. The FM is graduated on the side of it's clear plexiglass chamber with 5 hash marks. The hash marks are available in a variety of calibrations to suit many applications. A quick google led me to these common calibrations:

All values in inches of water vacuum pressure:
a) 4, 8, 12, 16, 20
b) 7, 10, 15, 20, 25
c) 8, 11, 15, 22, 25
d) 14, 16, 18, 22, 25
e) 15, 18, 22, 27, 30

As the FM detects vacuum a yellow cylinder advances in the plexiglass chamber. If the vacuum exceeds one of the five click off points then the cylinder is latched at that point. In effect the FM locks a peak vacuum reading value, and one of five values can be locked with the last value considered the "red zone" where air filter replacement is suggested.

There are some issues with using the FM outside of it's intended design use as a filter replacement indicator.

1) The resolution of the FM is the distance between the hash marks. Choosing (a) above, for example, if the intake plenum has an actual vacuum of 18 inches of H2O, then the filter minder will log it as 16 inches of H2O. Here the resolution is 4 since any value between 16 and 20 will be logged as a 16.

2) The accuracy of the FM is +- 10%. Again, choosing (a) above, if the "true value" of vacuum in the plenum is 20 inches of H2O, then the FM can read this anywhere between 18 and 22 inches of H2O and because of it's resolution some FM's may lock the reading as 16 while others lock it as 20 inches of H2O.

3) The FM, as installed in our LXi's, is a fast response sensor. This is true because BB installed the device directly into a 1/8" NPT bung tapped into the 7" intake plenum. As a fast response sensor, the FM is susceptible to measuring transient conditions. The Detroit Diesel Series-60 Installation Manual specs the following intake restriction tolerances:

All tests should be performed with the engine operating at maximum rated speed and wide open throttle (full fuel):

The maximum permitted inlet restriction for a system with a clean air cleaner is 12 in. H2O (3 kPa).
The maximum permitted inlet restriction for a system with a dirty air cleaner is 20 in. H2O (5 kPa).

What DD is measuring here is steady state intake restriction, not transients. The steady state condition specified is continuous operation at maximum rated engine speed and continuous full fuel. What it's not measuring is transients such as downshifts, on the fuel off the fuel, cruise mode immediately followed by full throttle full load. The FM can't distinguish between transient and steady state so is apt to report vacuum conditions created by a turbo boost surge or by slow or stuck wastegates. To make an accurate determination of intake plenum restriction we want readings at steady state max rpm, max fuel, max load conditions as specified by Detroit Diesel.

4) The FM is susceptible to it's mounting location. Detroit Diesel is very clear in where a vacuum probe should be tapped into the intake plenum. DD specifies 5 inches before the turbo and after the last bend. Installing an FM at an elbow, whether at the inside radius or outside radius, can distort the readings. Installing the FM at tapered reduction or expansion diffuser can distort the readings. The FM is also susceptible to dirt and grime. Any clogging of the port or of the FM can distort the readings.

Before I'd recommend cutting metal, we need a precise continuous real-time vacuum measuring probe. We need an analog sensor that has high accuracy, low resolution, high repeatability, and low response time, with the ability to measure and log steady state vacuum conditions. We also need a continuous real-time dash mounted display. We also need to tap the vacuum probe into the intake plenum according to the manufacturer's (Detroit Diesel) specifications. The Filter Minder doesn't meet these needs.

Only when these requirements are met can we be sure that the data we're collecting is meaningful enough to allow us to make thoughtful modifications to our intake systems. Until we measure with high quality measuring devices and collect accurate and precise data, we can't say that we know anything about the system. Anything less is hacking, not engineering.

Here's a link to pdf's of a high quality analog vacuum sensor and a display offered by Engineered Products Co that suits our needs:

http://wanderlodgegurus.com/Thread-Intak...61#pid1061

Here's a pic of your typical Filter Minder:

Filter Minder.jpg (Size: 25.16 KB / Downloads: 1650)

Spaghetti

Tue, 26 Feb 2013 16:59:52 +0000

Continuing on our 'WaGu/RaGu Room and Ristorante' theme:

Spaghetti, a slender noodle, draped in a dish intermingled with it's neighboring noodles, one picks up where the other lets off, each one different but similar, convoluted, not much on their own, but empowered in a bowl.

WaGu, a diverse set of individuals, sharing ideas and perspectives, advice and experience, on a common theme, the motorhoming theme, good on their own but empowered within a forum.

Not about which is best, which noodle has the perfect curves, as we all know there is no best. Whether it's forums or motorhomes or noodles, each one is perfect in the eyes of the beholder, perfect for them and for their use.

WaGu's carved a niche for itself. A friendly spot where people from a range of experience can meet, get to know each other, share tips, recipes, and travel information, in an all inclusive environment. We do have the goods, collectively we do, to get the job done.

As a rallying cry I offer a spaghetti western that to me reflects the spirit of WaGu, that is, a bunch of guys and gals getting together to do something with what's at hand, collectively empowered.