M116A3 Build

[noseoil]

Look for a cabinet shop supplier in your area & find some baltic birch (1/8") to see how it looks. It's 5' X 5' and fairly inexpensive if you like the birch look. If you go with paneling, I would try to cut it to shape & size first (make a pattern first to see that it fits properly) and do your finish outside on the bench. I wouldn't want to apply finish on a vertical surface ever, if it could be done laying flat on a bench. The ceiling is the same, painting overhead sucks! When I did my headliner, I did it on the bench, glued the canvas in place first, & then put it on in one piece. A bit wobbly, but it was done easier & looks good that way.

If the panels will fit inside the door, tack it up & glue it once it's stained & completely dry with a pin-tacker. That way some simple corner trim will cover the joints, ceiling edges, wall joints, etc. & make things much easier to deal with. If you use trim, there's no need to have completely tight seams & perfect fits. With the panel 1/4" too small in both (all) directions, you really just have an 1/8" gap to cover with trim at the edges.

Not sure about rolling the aluminum. Ask the Amish folks if it will work & listen to their advice. We rolled formica sheets all the time with just a cardboard edge folded over on the end of the sheet to protect it & then used twine to tie it off. Not so sure aluminum would take this type of treatment without bending or folding. I guess it depends on the thickness.

[lfhoward]

Thanks again (as always) for the great advice, Noseoil! I'm going to see if I can find some plain old flooring urethane tomorrow.

Today was an exciting day! I don't have any photos from today, but I'll describe it.

The trailer went on its maiden voyage today, a round trip of about 5 hours to Lebanon, PA. I stripped off the windows, fan, battery charger, and anything else that was loose and not permanently attached yet. Then I wrapped the power outlets in plastic and tied up the wiring, just in case of a shower. There was a 40% chance of rain.

The trailer pulled great! It rode even better than when I picked it up in VA when it was empty-- having weight on it softens the ride. I was able to (cautiously at first) go up to 70 mph with absolutely no problems on the PA Turnpike (which is the posted speed limit). The camper top stayed firmly attached and there was no movement at all of the cabin frame and no cracked wood or separated joints. It's a strong structure, securely bolted down.

On my trip, I had two goals (both found on Craigslist).

First, I met Mike in Phoenixville and purchased a 140 Watt, 24 volt solar panel for the top of the trailer, plus a Tracer MPPT charger that is super efficient. Second, I met up with Alan at a roofing company in Lebanon, to purchase 10 sheets of white, 10x4, 0.040 aluminum sheets. The sheets fit well in the trailer (with a little bit of curve to them), and since I don't have a back door yet, I ratchet-strapped them in. These sheets were seconds-- not because there is anything wrong with them, but because they are the wrong thickness for roofing! The thickness 0.040 is about 2x as thick as roofers need, and will crack when they double-bend the edges to connect roof panels together. I got the aluminum panels for about half of their wholesale price, and for about 1/3 of the retail price I was quoted closer to home. Definitely worth the trip.

By the way, Alan has a whole corner of the warehouse stacked full of these 0.040 sheets that he would love to sell, and there are pallets of all sorts of colors (anything that you might see on a roof). PM me if you'd like his contact info, if you need to get aluminum sheets for your trailer project.

Another fun part of the trip was people's reactions to seeing the trailer! People wanted to talk about it wherever I stopped -- gas station, convenience store, roofing company... People love it!

Happy Labor Day Weekend, everyone!

[S. Heisley]

It sounds like you did good both on the trip and the purchases!

[lfhoward]

Thank you, Sharon. Yes, it was a good trip! I'm glad to know the body I built is solid and safe on the road.

For anyone who's curious, here's a shot of the sticker on the back of the solar panel, the panel itself, and my stack of white aluminum sheet metal.



The solar panel is made by Goliath. It's approximately 4.9 ft by 2.2 ft, and is proportioned nicely for the top of the trailer. It weighs 26.5 lbs.


A stack of 4x10 aluminum sheets.

[lfhoward]

I figured out that this panel should do reasonably well to charge my battery bank if all I'm using it for is the fan, lights, charging electronics, and the occasional coffee grinder and kitchen small appliance. Here is the calculator I used:

http://www.batterystuff.com/kb/tools/solar-calculator.html

Some of the variables I put in:

Watts per hour of usage: 120 (which is 10 amps x 12 volts)
Hours per day: 3
System voltage: 12
Days of backup power needed: 4
(gives me 30 amp hours per day)
Amp hours of 1 battery: 80
(Need 3 batteries - which I have)
Hours of direct sun per day: 5
Panel size in watts: 140
(Need 1.08 solar panels of my size to recharge the system back to full every day)

Some days I might use more power, and some days less. Even if the panel is only recharging 80% of my usage on a per day basis, I could go for more than a week before having to plug in. With 3, 80 amp hour batteries, I can go 4 days at 30 amp hours per day with no solar panel at all and only bring my batterties down to a 50% level of charge by the end of day 4 (which is as far as I would want to go to protect battery life). The solar panel will allow for more daily usage and/or a longer trip time before having to plug in or reduce my usage to recharge the batteries.

[noseoil]

It should have plenty of power for your needs. I think you'll be surprised at how well it does, as even on a cloudy day it will be keeping things going for your small needs & large reserve capacity. Great job picking this stuff up & the trip!

[lfhoward]

It should have plenty of power for your needs. I think you'll be surprised at how well it does, as even on a cloudy day it will be keeping things going for your small needs & large reserve capacity. Great job picking this stuff up & the trip!

Thanks! It was fun to get the trailer out and on the road for the first time! I think it is going to do well on the road and off, because it is so strong.

[lfhoward]

So, after my journey to central PA for the solar panel and aluminum sheeting, I got a good sense of how the trailer pulled behind my Jeep. My overall impression was good, but there are some things that have bugged me in retrospect.

1) The shimmy at 55+ mph. The military tires are 36" bias ply monsters that are not balanced, and I don't think the military even does that, as the service manual says to drive no faster than 55. I had them up to 70, and the rotational resonance peaked at about 56-64 mph. The shaking wasn't as bad as when the trailer was empty (when I brought it home from VA) but it was still there.

2) One of the tires doesn't seem to be able to hold pressure and it is very badly dry-rotted. I pumped the tires up to 26 psi before leaving on my trip (the service manual says these tires are maxed out at 30 psi with a full load on the trailer), but by the next morning the pressure hardly registered. The other tire holds pressure well but looks like a fairly recent retread (possibly unbalanced too).

3) The gas mileage I got pulling my trailer was not too good. Using tow/haul mode, I averaged 12.2 mpg on that tank. One reason for that is probably the immensely heavy run-flat military tires and beadlock rims. Of course, I was towing a brick with a brick. But I was hoping for 13-14 mpg.


I've been looking into options. The military rims are 16.5 inches in diameter, a 8x6.5 bolt pattern, and are 8-bolt beadlocks. There are a few issues here.

1) The older bias ply humvee tires are very hard to find replacements for, even though the newer radial humvee tires are readily available. I haven't been able to find a matching one in my area.

2) The 8-bolt beadlock rims are too weak to run newer humvee radial tires (the minor issue of exploding rims) and the newer humvee rims have 16 bolts holding the beadlocks together. So, to run newer humvee tires I would have to get two of them and upgrade my rims also. $$$

3) I thought of running civillian tires on the military rims, but 16.5 inch rims are no longer used on any modern vehicles. Back in the 70's and 80's they were fairly common, but now there are only a few tire types even made for them. Super Swampers are one type, but I don't want those. All the 16.5 tires on Craigslist are so old they are dry rotted to crap.

4) This brings me to new civillian rims. 8x6.5 bolt pattern rims used to be the norm on GMC/Chevy 2500 pickups and vans, Ford F250 and E250 trucks/vans, and Dodge Ram 2500's as recently as 2009. I think the big three started using a different bolt pattern beginning around 2010 (at least for GM), but cheap 3/4 ton truck rims with an 8x6.5 bolt pattern are pretty widely available on Craigslist. I've seen them with decent used tires for fairly low prices, so I think I'm going to try to find some 16 inch civillian rims for my trailer. Hopefully I can get them with reasonable A/T tires already mounted on them.

It will be an experiment. In the best case, new rims/tires would reliably hold pressure, make the ride smoother, and give me back 1-2 mpg from lower tire weight and slightly lower trailer height (if I'm running 31's, 32's or 33's instead of the military 36's). I'd settle for 2 out of the 3!

[KCStudly]

I doubt you will see that big of a mileage increase just from changing to lighter tires, but maybe a tad... enough to register. More likely you will see an improvement once you put the windows in and make it less of a parachute.

p.s. I think Noseoil was referring to the rating of your solar panel, not the strength of your cabin.

[lfhoward]

I doubt you will see that big of a mileage increase just from changing to lighter tires, but maybe a tad... enough to register. More likely you will see an improvement once you put the windows in and make it less of a parachute.

p.s. I think Noseoil was referring to the rating of your solar panel, nit the strength of your cabin.

Yeah, you're right. Whoops! Not sure why I went on to talk about the ride without some sort of transition.
Noseoil, thank you for your thoughts about the solar panel and battery bank.

[lfhoward]

I doubt you will see that big of a mileage increase just from changing to lighter tires, but maybe a tad... enough to register. More likely you will see an improvement once you put the windows in and make it less of a parachute.

It will be interesting to see. My Jeep came with 29 inch tires and since I'm running 30.5's now with the lift, I've lost about 2-3 mpg on the highway. I lose about 2 more mpg when I put the roof basket on. My model of Jeep is a bit underpowered with the V6, so these modifications can make a big difference. I was extending the same line of reasoning to the trailer... Larger heavier tires will register an mpg loss, as well as taller aerodynamics (assuming the extra weight of the trailer also exacts an mpg toll that is equal in both cases). You're right that anything I can do to minimize wind turbulence, like installing windows, will help too.

One interesting thing was although I got 11-12 mpg towing the trailer on the flat, those numbers went up to 15 when I was following a semi truck! So a lot of the mpg loss is due to wind resistance.

[KCStudly]

If you did not recalibrate your speedo after the tire size change your mileage may not be as bad as you think. Bigger tires roll further per rev. That's about a 5/ct difference in roll out, or about 3/4 mile in 15.

On the trailer tires the weight takes more energy to get rolling, but the big hard tires with little sidewall flex may actually roll easier with a light load than a similarly sized softer LT tire once they are up and rolling. I'm surprised that they spec with such a low tire pressure (maybe the 30 psi is a minimum?). Usually big heavy truck tires run very high pressures compared to LT or car tires.

Lighter is always better from a performance stand point. Beef for beef's sake is wasteful, unless, of course that is one of your goals. I mean, everyone likes to watch a big monster truck do its thing (for a few seconds... until they run out of fuel or break)... but I would rather drive a race buggy (all day)... and pay for its fuel, too. IMO it is better to engineer strength in where it is needed and to choose your materials wisely. Less weight means less stress on everything, less mass to accelerate and decelerate, and easier recovery, too.

[noseoil]

You have two things working against you when towing, weight & wind resistance. On the weight thing, you can run hard tires so there's less of a "load" from the tire on the pavement as KC mentioned, but pulling uphill is dragging a bigger load behind you. There's not much you can do about that one, weight is weight & it takes more ponies to pull a load up a hill than run down one.

The wind thing is just a question of how big the frontal area is, which isn't blocked directly by your vehicle, plus any turbulence it's dragging along behind it as a consequence of shape & speed. You're punching a bigger hole in the air with a shoe-box being towed behind a brick. The front is angled at the top, but the total frontal area is the issue with a larger box which sticks out further than the vehicle in any direction. The only way I know to beat some of this is to tow at a lower speed, since the shape you have is already a constant & it's a bit late to change it now (chainsaw perhaps?).

If you tow at 50 mph, the wind load on a flat surface is about 6.4 pounds per square foot, at 60 mph it goes up to 9.2 psf & at 70 mph it's up to 12.5 psf or about double what the wind load is at 50 mph. At 75 it's 15 psf & at 80 mph you're looking at 16 pounds per foot of frontal area. Tow slowly to save gas!

Where you will come out ahead is once you're stopped & camping. That extra space & comfort is worth a few dollars for gas when you're set up & relaxing. You get to pull up, park & watch others set up their tents. After a heavy rain or wind storm, you get to enjoy the campsite carnage over a cup of coffee or a beer....

[lfhoward]

Today I sanded the seams flat where the PL premium caulk was sticking out, wiped down the sawdust, and then applied the first coat of urethane sealant to the camper top.

Here is what I used:



http://www.minwax.com/wood-products/clear-protective-finishes/interior-exterior/minwax-helmsman-spar-urethane

This type of urethane is for outdoor applications that see expansion and contraction due to heat and cold.

The first coat used about 2/5 of a gallon, but the wood was soaking it up like a sponge. I am hoping to get 3 coats on with this gallon of urethane sealer.

[lfhoward]

If you tow at 50 mph, the wind load on a flat surface is about 6.4 pounds per square foot, at 60 mph it goes up to 9.2 psf & at 70 mph it's up to 12.5 psf or about double what the wind load is at 50 mph. At 75 it's 15 psf & at 80 mph you're looking at 16 pounds per foot of frontal area. Tow slowly to save gas!

Where you will come out ahead is once you're stopped & camping. That extra space & comfort is worth a few dollars for gas when you're set up & relaxing. You get to pull up, park & watch others set up their tents. After a heavy rain or wind storm, you get to enjoy the campsite carnage over a cup of coffee or a beer....

Thanks for the aerodynamics data! The tow speed will definitely not be 70 in the future. The Jeep is much happier towing at 60, but that's right where the resonance was with the unbalanced milirary wheel(s). I'd be happy just to have a set of regular wheels that runs smoothly and holds air reliably. I will be looking at a set of GMC wheels later this week.

You're right about the comfort and dryness of a good teardrop! That's the main reason I'm building it!