Would love feedback on my original, tiny trailer design

[deleted]

Hi Norm,

Thanks for all of the insights and links!

First, I had seen the floor plan for the new Knaus right after I saw an original at the Petaluma TCT rally two weeks ago! http://theflirtyguide.blogspot.com/2012 ... ntage.html I LOVED it. If only originals were available (and affordable) I would just get one of those instead of building as the dry weight of the original works with my tow vehicle.

And that's brilliant about linuxmanxxx's foam walls! Then I could use the design idea I came up with after Mike's suggestions. I was worried that adding an extra foot and going to 7' long would add too much weight by adding an additional 18 sq feet of wood to accommodate that one additional foot in length.

The shower pan built in floor idea had not occurred to me. But I like it a lot. Then I could have it empty into a grey water tank under the trailer. I found one that is only 3.5 inches high which is important since my floor will be low. It only has a 1.75 gallon capacity but I'm thinking I'll use less than that each time I shower. I'm going to have to seriously rethink this part of my design.

The rubbermaid as shower stall measurements I listed in the blog are so that after use I can pop it up on a counter for the night, It's small but I know it will work because when I was a kid I learned to bathe, in a bath tub, but simply crouched in front of the spigot and using a plastic container to pour water over to rinse. I sometimes did it just for fun because the pour container was always in the tub. That's how my dad has always taken "economized showers." Not sure if he learned that growing up in Hawaii or as a POW for two years but by the time I was born that was how he'd decided showering would be for the rest of his life. I figured this won't be too different except with the wand from the solar shower bag it will make it easier to rinse. And the shower curtain can be set to a wider dimension with the ends tucked into the catch receptacle to give more maneuvering room.

And thanks for more confirmation on the cabinetry and for the suggestion that I can go ultra-light with glue there. When I first sat down to draft things out I started with 1/2 inch wood for the cabinets. LOL. Rookie move

Question
At this point I'm leaning more towards skipping the 2" wood framing over the chassis and simply laying the floor down directly on the chassis. This will give me two additional inches of interior height. Good idea? Bad idea?

Question
Do you know (or does anyone else know) if anyone has ever used the aluminum siding for their (insulated) interior cabin ceiling as well as their exterior? That would allow me to avoid using the luan for the interior which I would like to do if possible. Or does it heat up too much and stay too hot during summer?

[doug hodder]

Yup....just lay the flooring directly on the frame....tons of us have done that and that's how the originals were built....and Luan is much cheaper and less hassle than aluminum to do the interior walls if dollars are a concern...PS..don't forget about the R value of the alum. vs ply. Could have more chance of condensation on the aluminum ceiling.

I think the most important information to you is what Sharon posted previously....lay some tape out on a floor and then mark out all the things that you think you will need in it. I'd bet you'd be surprised on just how small it gets suddenly. It may or may not be important to you in the future or how you camp, but if it's built really small, chances are, it may not have much resale value as it's built so user specific. Assuming you will build another...like that has never happened on this forum. Others opinions may differ. Doug

[deleted]

Thanks for answering my question Doug. Yeah, if I ever want to sell my trailer down the road the ad header will read "Tiny Trailer for Shrimpy Person." LOL. Honestly though I'm not too worried about resale. After being featured regularly on my blog this trailer will probably become almost as famous as my dog and his crazy Halloween costumes http://cutestdogever.com. I'm sure if I ever post that it's for sale there will be someone who'll want it. Knowing me I'll even offer to deliver it to them just for the adventure of it all.

I was thinking I'd insulate the ceiling especially if I used aluminum on the interior. The luan vs aluminum is an eco-conscious issue for me after reading about how the tropical luans in particular are a deforestation issue in the countries where the wood is harvested. If there are any eco-friendly luan options I'd go that way but so far I haven't found anything online that leads me to believe there are. I have yet to call a lumber shop though so perhaps I'm just in the dark on this.

I did mark off my living room floor right beside our fireplace which has a 12" brick shelf/platform in front of it to mimic the cabinets. Maybe tonight I'll mark off the carpet and pull the coffee table up to it, lay out my camping mattress and sleep there to really test things out. I'll report back tomorrow how it went

I'm predicting there's a 50% chance I'll wake up with the cat and/or dog piled up on top of me even in such a narrow space

[alaska teardrop]

Stacie, You certainly have some cool ideas, tool resources & enthusiasm to follow through. You've asked for a critique. I'll address the construction, mostly pertaining to weight, because I believe your plans, so far, will put the trailer way over your targets. So here goes, hope it doesn't rot your socks.

The frame design has way more steel than you need & for a variety of reasons a two rail 'V' tongue is more advantageous than the single tube. Here is a light weight layout to consider that can be adjusted to your needs. viewtopic.php?f=35&t=12220

Your cabin floor frame could be almost the same. Move the front wall back a foot, add the storage box frame base & shorten the tongue 4". You're there at the proper tongue strength.

I see no advantage for your using the Timbin axles. A #8 1100# Dexter acts as the main crossmember & doesn't require a heavy frame to mount to. It weighs 20# less (51#), alignment is built in, you can order with or add brakes & determine the ride height. Also, a Dexter axle with a 22-1/2 degree up start angle will lower the ride height to about 9" using the tires you're planning on (better handling & less wind resistance). Aluminum wheels weigh less than the steel wheels in the illustration.

Since you're building a welded steel cage & sheathing the outside with aluminum, you don't need any exterior plywood - floor, walls or top. Consider a stressed skin using .040" paintable mill finish aluminum attached with VHB tape & rivets. Examples in my album. (Note though, that since you'll have the steel cage, you wouldn't need so many rivets & the thicker aluminum of the Northern Lite. And since you probably won't be driving the Haul Road on a regular basis, the extra steel & thicker aluminum of the Alaska Teardrop). With .040" you won't need the extra weight & ugliness of the diamond plate. Also, because you don't require a lot of insulation, reduce the cage tubing from 1" to 16 ga.x 3/4" sq. Only place the tubing in the walls & roof where you need attachment points. Your side plan, for example, shows about five unneeded pieces per side.

Speaking of insulation, extruded polystyrene is best for interior moisture control. Dow makes 3/4" blueboard.

I think the shape of your trailer is fine, however, if you made it travel in the other direction, it would handle better & be more efficient.

You mention a hatch for cargo, but really Stacie, what are you going to haul that won't fit through the door, in your car or some other transport? The hatch will add weight & grief to your build. If you changed the direction with the tall wall at the back, there would be a place for a nice window with storage above & both sides where the weight is needed for balance.

Now, those under carriage boxes. Again ask yourself what will go in there that can't go in the trailer or car, because they will add a lot more weight & grief making doors & such. If the spare from the car doesn't fit, get a space saver wheel & tire from the recycle yard & keep it in the trunk.

I would recommend powder coat over galvanize. Besides you can pick your color.

Fred

[deleted]

Woke up in "The Chute" this morning. Turns out 28"x69.75" is more than enough room to get a good night's sleep. I could easily flip from side to side and didn't wake up once from bumping into the fireplace or the row of plastic storage tubs I lined up on the other side (the coffee table had such a sharp corner I decided against using it just in case). I could even lie on my side with my knees bent and pulled up all the way and still had plenty of room before I'd hit a wall. The dog and cat each came to visit me for a bit but I woke up all alone.

So now I'm debating. The 4'x6' layout really is perfect. But, I do like Mike's idea about moving the cabinets to the front and keeping the rest of the floor open. The dog would definitely fit better in the cabin that way when I bring him along.

[deleted]

Thanks Fred! I needed your critique!

Off the cuff I can say that I am completely open to your suggestions about losing the exterior wood for the sides and top, changing the shape of the chassis and losing the unneeded bars from the sidewall frame. I knew I had gone too heavy but didn't know what was actually unnecessary.

After speaking to a trailer designer on the phone yesterday morning I'm pretty sure the solar system is unnecessary for my needs. I'd like to design it so that if I ever start to go boon docking for a week or more I could add one in so I may go ahead and leave the space for a panel on the roof and create a space for the wiring to run down from the panel to the charger. But for now I do want to lose the dropped storage. If I only need to house the inverter it means I can use that one extra cabinet for my clothes, etc. I can also switch to one water container beneath the sink for grey and one for fresh instead of keeping two grey water containers there for my overnight trips.

The one thing I'm considering but at a glance don't think will work is to flip the entire shape the opposing direction. The door, I fear, on the more rounded end would make entry/egress more challenging. What I can do is to keep it the way it currently is but add more arc to the front end to make it more similar too, but not as rounded as, the rear.

Also, the rear hatch I'd really like to keep. If the only reason I wanted it was to haul things you're right, it would be necessary. But I also want it to be able to enjoy the view when I'm in a beautiful location, for the fresh air when the weather is good, and for the more social aspect of being able to have it open while at a rally or if I'm out camping with friends. The trailer is small so being able to open up the back will be an extra effort that's worth the trouble. The extra weight I'm not keen on but if I can make it work I'd really like to keep it

One thought crossed my mind. I assumed the tow weight meant the weight the car could bear both in and behind it. Your mentioning I could move things to the trunk, that means I don't have to add that weight in at all because the car itself can carry a separate load that doesn't impact the tow weight?

[KCStudly]

Your TV should have a couple of ratings that matter here.

GVWR or gross vehicle weight rating, or simply GVW. Everything all up that goes in the car or truck; wt of car, people luggage, pets, etc. You may also have individual axle weight ratings (i.e. limits on where the weight can be loaded in the car/truck).

Towing capacity and max tongue weight. Pretty self explanitory.

GCWR or Gross combined weight rating. In here lies the answer to your question. The GCWR is very seldom ever the same as GVWR plus towing capacity. Usually it is less than the two combined. Therefore, the more you put in your TV the less you can tow, and vice versa.

Usually this info is on a sticker located in the driver's side door jamb, or glove box. If not, check your owner's manual or go on line and look up the specific make, model, and option package of your TV.

[alaska teardrop]

Thanks Fred! I needed your critique! One thought crossed my mind. I assumed the tow weight meant the weight the car could bear both in and behind it. Your mentioning I could move things to the trunk, that means I don't have to add that weight in at all because the car itself can carry a separate load that doesn't impact the tow weight?

Stacie, Yes you're right as to the pulling capacity. But what is your tow vehicle & maximum hitch weight?

The suspension is designed for a given maximum load over the cars' weight - front & rear passengers, luggage (most of which is between the axles) + a reasonable hitch weight. Other load considerations are the brakes, clutch or automatic transmission limitations, tire load range & strength of the hitch attachment points. Front engine cars are designed with weight & brake bias to the front. If the rear is overloaded, the front wheels become light. This causes dangerous handling & braking. Because hitch weight is the furthest back, the weight is leveraged like a teeter-totter with the rear axle as the fulcrum.

By designing with the axle so far back & so much weight ahead of it, your hitch weight skyrockets.

Here are some precise measurements from the Northern Lite that you might interpolate to your build. 900# gvw - 525# vw = 375# load. Front weight placed on the tongue. Rear weight placed from just ahead of the axle & back to the rear wall. No weight in the middle, except for a 20# mattress.

1. 17% 90# tw w/20# mattress

2. 25% 155# tw w/ 70# front

3. 30% 180# w/100# front

4. 12% 95# tw w/30# front - 225# rear

5. 12% 105# tw w/ 30# front - 325# rear

6. 15% 137# tw w/70# front - 285# rear

7. 17% 156# tw w/100# front - 255# rear

8. 9% 82# tw w/0# front - 355# rear

Numbers 2, 3 & 7 are unlikely configurations & to much for a small car. Number 6 is sketchy for a small car. Number 8 is an unlikely configuration. Numbers 1, 4 & 5 are most likely configurations & ideal for a small car.

I believe a truly light weight trailer will handle best at high speeds with the most weight bias to the front within reasonable consideration of the tow vehicle's hitch capacity.

The one thing I'm considering but at a glance don't think will work is to flip the entire shape the opposing direction. The door, I fear, on the more rounded end would make entry/egress more challenging. What I can do is to keep it the way it currently is but add more arc to the front end to make it more similar too, but not as rounded as, the rear.

Also, the rear hatch I'd really like to keep. If the only reason I wanted it was to haul things you're right, it would be necessary. But I also want it to be able to enjoy the view when I'm in a beautiful location, for the fresh air when the weather is good, and for the more social aspect of being able to have it open while at a rally or if I'm out camping with friends. The trailer is small so being able to open up the back will be an extra effort that's worth the trouble. The extra weight I'm not keen on but if I can make it work I'd really like to keep it.

Your alternative plan for under bed storage above the chassis sounds better. (Heaviest stuff to the rear over the axle).

OK - fine California weather. How about turning your shape around with a good size back door & a window on both sides? This would allow you to move the axle forward & balance out a well planed load.

Well anyway Stacie, the important part is to build what you want & enjoy doing it. Heck, if it weighs too much, buy a new tow car.

Fred

Edited the percentages - brain fade

[deleted]

Thanks for the info KCStudly and Alaska Teardrop.

My tow vehicle will be a 1994 Acura Integra, RS ,4 door sedan:

Vehicle Weight: 2670 lbs
Tow weight: 1000 lbs
Tongue load: maximum 100 lbs or 10% of trailer weight

My owner's manual instructs to put 60% of the cargo towards the front and 40% towards the rear.

The GVWR is, according to my manual, printed on the inside of my door. But I didn't see it there, not surprising that it may have fallen off since I've had the car for so long. I'll do a better inspection of alternative locations tomororw. The TV has 137,000 miles on it. It's always run great. My understanding is it's typical for this car to make it 250,000 - 300,000 miles so I could be driving it around for years.

Alaska Teardrop I'll play with the layout and door placement more. I did see one build thread or journal somewhere where a guy put his axle forward and his entry behind it. I'll have to look for it again and really study the 1, 4, and 5 options you shared with me above.

Ideally when you and the owner's manual say "rear" does that mean to keep all of the weight on or in front of the axle and nothing behind it?

How about turning your shape around with a good size back door & a window on both sides? This would allow you to move the axle forward & balance out a well planed load.

Yes, I want a well balanced load. Since I'm doing this from scratch I want to do it right. Thanks so much for all of the time you're all investing in sharing your knowledge with me. I really appreciate it.

[mezmo]

Hi Stacie,

I thought I'd mention a few things/links for info purposes.
Applying plywood to the frame as a floor method is a very
simple and direct method. But I'm an advocate for insulation
as it helps with condensation, sound deadening and keeping warm/cool.
I happened to recall these insulated 'honeycomb' SIP-like panels:

http://singcore.com/
http://www.superhoneycomb.com/
http://www.youtube.com/watch?v=oGokTnuD ... ure=relmfu

They are located in Washington State. The panels can be
skinned in various skins - aluminum. plywood, FRP...etc.
Pricing would need to be investigated.

I wonder if the inventor was inspired by hollow core door
construction or fusuma construction when he came up with
them ? They would save alot of work and build time.

Here are a couple links for a guy using it for restoration and
modification of a 1956 Airfloat House Trailer and his daughter
using them to build a somewhat 'larger'Tiny House on a trailer
frame:

http://www.everyonecandance.com/Airfloat_Process.html
http://mytinyabode.blogspot.com/

Also, since your build is small and you want quality materials I'd
forget luan and use Baltic/Finnish/Russian birch plywood instead.
It has high ply count per thickness and no voids and it's edges can be
a decorative element. And is available from 1/16th of an inch to a bit
over one inch in thickness. And natural finished birch plywood is really
beautiful. Grain pattern can vary alot though, but it is generally not
overpowering but very pleasant. Think shibui here. It was the main
traditional interior surface on most US TTs and house trailers until the
late 1960s - early 1970s:

http://www.digplanet.com/wiki/Birch
Also Google, and Google Image, birch plywood and birch plywood
furniture for examples and info and possible sources. Locally, cabinet
shops and specialty lumber yards should have that and also 4x8 sheets of
American made birch plywood. Avoid Chinese made and bigboxstore plywood.

Here's one brand that's formaldehyde-free:
http://columbiaforestproducts.com/PureBond
http://columbiaforestproducts.com/Produ ... oodPlywood

As you mentioned galvanizing, it is an additional cost I'm sure, but my having
dealt with quite a few rusty trailer frames/chassis in my time, I'd be in favor
of it if I could afford it. Derusting and repriming and repainting a rusted
frame underneath a trailer is more of a punishment than a project ! And
I'm not a fan of powdercoating either. From what I understand that is not
cheap either, and you can't have anything on the frame that'd be melted/
affected by the oven/heat they use to melt the powder into a finish. It is
also affected by the quality of the job/applkication when done. I have some
decorative steel yard fencing that is powder-coated and it is all sloughing off
and the steel is rusting. Instead, check out rust converting and rust encapsulating
primers and paints. They seem a better approach if one is not doing galvanized.
Just Google "rust convertion primer/paint" and "rust encapsulating primer/paint"
and there is a lot of info/brands.

The European Caravan/RV manufacturers are way ahead on building light and
coming up with new build methods. Here is an interesting approach from the
UK's Elddis brand I came across recently. They hardly use any fasteners in their
construction but have gone to all adhesive joining/bonding everything together.
Like what is used/done now in Formula 1 race cars, yachts and airplanes. Their body
panels are basically like what linixmanxxx's been doing, joined by the new all-
adhesive bonding of all the panels/components together with the new high-tech
adhesives. If you click on "Request a 2013 Brochure" in the bottom right, then in "Brochure
Downloads" click on the "2013 Tourer Brochure" and look at the 2nd and last pages that
talk about the "SoLiD" method. Also note the minimal galvanized steel chassis/frame.

http://www.elddis.co.uk/

Since you want to keep a rear door/hatch just have a look at these:

http://crickettrailer.com/index.html

It's not very pretty, but I love the functional approach they've taken.

Also, I came across this recently too: The "Cross-Over Trailer" concept by Ross
Design, the in-house design function of the Vohringer Group, a German caravan
[wohnwagen] interior component supplier/manufacturer. It's intended to meld the
tow vehicle's air movement into the trailer's for an aero benefit. It is also light
weight and narrow and has a large rear opening:

http://www.voehringer-gmbh.net/rossdesi ... ossdesign/
http://www.v-group.com/uploads/pdfs/CRo ... %20eng.pdf

I don't know how wedded you are to the radiused ends of the older style TDs and
canned ham TTTs [I suspect you really like the "cute" factor in those rounded end
designs] but I thought this was an interesting modern flat panel design with some
'aero-ness' thrown in.

I've just remembered a way you could keep the rounded ends and still have a rear
hatch as well as some covered rear space. This is based on a camper trailer I saw
a LONG time ago when I was a kid and went with my Dad looking for/at TTTs/campers.
One that we looked at had the canned ham profile's rounded ends - which were almost semicircular
actually. It was sort of what we on the forum would call a "slouchy" TD. The body was about
6ft wide and about 10ft long and 5ft tall. The rear semicircular end was hinged at the
roof where the radius ended and the roof plane became flat. The whole end cap lifted
up and it became a mini-barrell-vaulted roof supported by two poles at the rear corners. This
provided a roof over the galley's work area. There were also canvas sidewalls available to enclose
that area under the roof if wanted. The rear galley area is built in at the back
like a TD's, except that the galley and bulkhead wall ended @ 20in from the passenger
side wall so that there was a doorway/opening into the sleeping compartment which
had double bed sized bunks located longitudinally front-to-back and a front closet at
the end of the "hallway" on/in the front curved section, which was also thusly positioned
ahead of the passenger side sleeping compartment side door. I believe there was
a small interior door closing off the rear entrance to the sleeping compartment too.
There was a single pane longer horizontal shaped window for each bunk level on the
trailer body's driver's side and an entry door and then a square two pane awning window
on the trailer body passenger side, between the entry door and the rear of the trailer.
-Anyway- maybe you could utilize the rear liftup mini-barrel-vault roof aspect of it if
you are going to keep rounded ends on the profile.

Click on Pic to see larger view:



Maybe a variation on that could meet your needs. You could even have the rear galley be a
movable unit, that'd swing out 90 degrees from the travel position like a lot of the Australian
off-road campers kitchens do.

Wow, time to close this up ! Sorry for being so lengthy, I must have gotten on a roll here
somewhere along the way !

Cheers,
Norm/mezmo

[alaska teardrop]

My owner's manual instructs to put 60% of the cargo towards the front and 40% towards the rear.

I think the manual generalizes, because it doesn't know the weight configuration of every trailer. 10 - 15% tongue weight is considered proper.

Ideally when you and the owner's manual say "rear" does that mean to keep all of the weight on or in front of the axle and nothing behind it?

No. It's fine to have weight behind the axle as long as it is correctly balanced with the front & not concentrated too far back.

Fred

[deleted]

New illustrations based on your suggestions Alaska Teardrop!

New Silhouette with shape reversed. By narrowing the door by 2 inches to 20" wide it works in front of the axle, now pushed forward:



I also changed the rear top arc making it smaller to allow for a a more straight rear hatch. I don't know Sketch Up (just Photoshop) but working from Norm's illustration I came up with, and really like, this a lot!



And the cool thing is if I can bend awning rail into a rounded 90º arc I can add sidewalls to create a single or multi-sided tent by adding the rail to the inside of the hatch. I skewed the perspective just a bit:



Norm THANKS for the long post and for identifying good wood options based on my request. I've already started checking out some of the links.

Still working on the interior layout. I've decided to stick with the 4'x6' size since the 28"x69" sleeping area worked really well for me. I'd also like to keep to the door on one side and a similar sized window on the other as opposed to a door and window on each side to help reduce weight, cost, and potential leakage points.

Thanks again to everyone for all of your help!

[KCStudly]

Looks cute!

I would move the porch light to the rear of the side door, and arch the top of the door along the roof line, similar to what big Mike did in his 10' Foamie Standie build.



More headroom that way.

[deleted]

Alaska Teardrop here's my second pass at the chassis shape. I added in the one extra piece of metal between the tip of the A shape. You didn't have it in yours but is it a good idea for extra strengthening?



And the MIG welded steel tube sidewalls. Not sure if I've gone too far the other way now making the walls too light.

[deleted]

Thanks for the picture of Mike's foamie! Oooooh, I was sticking to the rectangular door to keep things easier. But if you think I can do a shaped door I'm on it