Squaredrop design

[jelkins]

Squaredrop design I am fixing to start building, thoughts?

 

[Pmullen503]

Hard to tell from the drawing, but are the wheels back far enough for proper tongue weight?

 

[jelkins]

Hard to tell from the drawing, but are the wheels back far enough for proper tongue weight?

It's at120" from tongue, I think it may be an inch or two forward but loaded with the everything on the front I think it will balance ok. Plus I'm looking at a 20/40 gallon water tank which I have room to move infront of the axle but not aft of so that can help with getting 10% to the tongue.
Or is that a bad plan?

 

[Tony Latham]

It's at120" from tongue

It should be at the 40/60 point on the frame, regardless of your tongue length. I, too, think the axle is too far forward. If it's too far forward, as you may know, you will have a squirrelly-pulling trailer to the point of being dangerous.

and a 20/40 gallon water tank which I have room to move in front of the axle

And what happens when your tank is empty?



Tony

 

[Onajourney]

A 6x12' without galley or much storage?

 

[jelkins]

A 6x12' without galley or much storage?

First door in front is for fridge and other storage, second small door is for kitchen slide out, haven't got the details for it yet.
Storage is under the beds and a cabinet between them. (back cushion is actually a seat/bed)
Also, on the drivers side in the front will be batteries, charger, solar, and other storage.

 

[working on it]

Nice profile, but not a lot of storage space shown; I suggest getting a large capacity tonuebox to help. It'll help greatly with both storage and weight balance problems, IMHO.

Ever since I started building my 4x8 squareback (squaredrop) trailer, I've been struggling to achieve a decent weight balance, while overstuffing my trailer with all my gear. I finally achieved the balance I sought, but it took me a decade to reach it.

The 50"W x 60"L frame I used had to be extended to get a 4x8 floorplan (what I always regarded as traditional, and easiest to build using plywood sheets), but I made the (initial) mistake by adding 12" in front and 24" in the rear, making the axle centerline too far forward. I had thought that the 24" in the rear would be a good size (24"deep x 48" tall) for a galley/storage area, but I immediately overstuffed it with heavy items (permantly loaded: generator, A/C unit & ducting, Coleman gear, battery, spare fuel, Aquatainer, frozen goods cooler, etc.), which made the tongue weight about 40 lbs, total weight 1280 lbs (unloaded with perishables, clothing, main beverage coolers). Not good, at all. I had to make a single beam weight distributing set-up to be able to take the trailer on my first trip, even though I added 150 lbs of gear into the front of the cabin, to bring the total weight to 1430 lbs.

I continued to use the weight distributing hitch for years, while modifying the trailer and its' loadout, moving weight forward for better balance. There were too many changes to list here, but the best/most worthwhile contributors to getting a better balance were the tonguebox (loaded with battery, electrical cords, extra lighting, spare parts, some camping tools, probably adding 250 lbs) and the double-stacked racks, mounted over the tonguebox & spare tire, which really helped. Two canopies and my pantry box added over 140 lbs, alone.

Later additions brought the total weight up and up, but I made sure that they were either neutrally-balanced or forward of center, and now the trailer is done...nothing will be added, and the balance goal has been reached. I still tow with the weight distributing hitch (makes me feel safer with it attached), but it's no longer needed.

 

[jelkins]

Nice profile, but not a lot of storage space shown; I suggest getting a large capacity tonuebox to help. It'll help greatly with both storage and weight balance problems, IMHO.

'
A lot of good information, thanks.

I have the 30"x76" box in front of the main cabin for batteries, tools, fridge and other components. There is also a shelf at the top of this box for storage. There will be under bed storage in the front of the cabin and a portapoddy stored on the driver side with 5 gallons of water in it. I am worried about having the opposite problem you are.
With our current popup when loaded most of the weight is on the tongue, and I would like to avoid that with this design, but of course as already pointed out what about when there is no gear or water packed.
I am not sure how much the permanent weight vs load weight will be in that front box. Maybe a spare tire mounted eventually to the front as well.

Both the front bed and back seat ar 16 inches off the floor with planned storage under them. I plan to have them both raise up to get to the storage with external doors as well. There will also be a 20/40 gallon water tank, and Propane bottle.
There is a 60x29x20 cabinet in-between the front and back. Opposite the door.

I guess my real concern with the axle placement and design is most of my forward storage has a long arm were as the aft storage doesn't so it would take a lot more weight to offset a "to aft" axle and not much to offset a "to forward" axle.

I am quite familiar with weight and balance as I am a private pilot... I am just worried I will end up with the axle to far back then when loaded have to much weight on the tongue.

Thanks.

 

[twisted lines]

60” tall almost looks worth it

 

[jelkins]

It has begun

 

[Tony Latham]

I am just worried I will end up with the axle to far back then when loaded have to much weight on the tongue.

I assume you are aware of what happens with too much aft weight?

[youtube]6mW_gzdh6to[/youtube]

It's not like you can dip your nose and add power.

Tony

 

[chopperwalker]

It wasn't apparent to me in the responses but if you compare the first two sketches it looks like the overall length increased and the wheel was moved back relative to that.

 

[jelkins]

I am just worried I will end up with the axle to far back then when loaded have to much weight on the tongue.

I assume you are aware of what happens with too much aft weight?

Tony

yep, but I also don't want all the weight on the tongue either. As I have mentioned most of the storage is towards the front of the trailer making most of the weight there when loaded. So I am just trying to make sure it's good both ways, loaded and unloaded.

It wasn't apparent to me in the responses but if you compare the first two sketches it looks like the overall length increased and the wheel was moved back relative to that.

Actually I ended up shortening it about 10" inches to keep the axle closer to it's original placement to allow room for the door and bench seat behind it.
Currently the overall box length is 165" with axle at 94" which is 5" shy of the commonly used 60/40. Tongue length is currently 72" allowing some wiggle room there.
I used https://www.engineersedge.com/calculato ... alance.htm which should keep me just over 10% unloaded.

After looking it seems I have gone through a few variations... you are correct in that the second sketch is longer than the first, but I ended with the numbers listed in this post. 165" long axle at 94" and a tongue of 72".

James

 

[jelkins]

latest version

 

[chopperwalker]

I really like your layout. I've been drawing up a similar profile for my trailer but I am hung up on it having standard cargo use still. Part of me wants to move on and build out similar to your interior.

 

[twisted lines]

I really like your layout. I've been drawing up a similar profile for my trailer but I am hung up on it having standard cargo use still. Part of me wants to move on and build out similar to your interior.

Me too;
And I have two, trailers that will haul a stack of plywood

 

[jelkins]

2017 sketch, hope it helps

 

[eLink]

Looking good so far!
When you are ready to fine-tune your design you might find it helpful to break all of the parts into separate components. You can then lay them all out and get them ready for CNC milling!

 

[chopperwalker]

I do the same as eLink. And even with out CNC, you can draw 4x8 plywood component and layout it out underneath the components on the ground. Makes it easy to plan material usage and cut order.

 

[jelkins]

Took it to the scales today, 1600lbs on the trailer axle.
I still have quite a bit of the small details to finish with most of it being in the front.
The tongue weight percentage is currently at 17.5% and while that's close with everything remaining and the storage being in the front I feel it will push it closer to 20%.
On the scale the front axle was 2640 and the rear was 2920, they are both rated at 5500lbs. Without trailer the front was 2700 and rear was 2640. Total was 7160 and my JLU's GCWR is 8016.