Frame Input

[Eddielbs]

Hello, I'm looking for input on the frame I am thinking of building.. Please let me know any of your thoughts on this subject good, bad or indifferent ... I'm kinda looking for something like the frame used on the Larry and Diane's Outback teardrop but i'm going to modify it a little for my use.(':thinking:')

[asianflava]

Just some observations:

Ditch the diagonals. You are using a 3x3 tube for the tongue, it is plenty strong on it's own.

You probably don't need all 3 cross braces. You'll definitely need one for the tongue. If you use a torsion axle, you won't need the rear one either.

The body of a teardrop is very strong by itself, the purpose of the frame is to provide a good solid attachment for the tongue and the axle.

[G-force]

I am also planning to build a similar trailer for my Grumman build. I ditched the single 3x3 neck in favor of a triangulated 2x2 neck...the reason Larry did his that way was he could jack knife it 90 degrees with his jeep. My truck is a lot wider, and would requier a very long neck to do that. So simpler and stronger is a V neck. For me, raising the coupler 2 inches is also a plus with my tall truck. A few items to consider:
1) Wall construction, if your building thick insulated walls, you might want to go up to 58 or 59" width and make sure you maintain enough inside width to hold a standard 54" wide mattress.

2) Floor thickness...if your going with 3/4 with framing, you probaly wont need 3 cross members, but I chose to have 3. Spaced evenly, the rear one is just aft of my interior/gally seperating wall and that is where I wanted support for the heavy batteries and icechest.

3) How did you come up with 52" axel setting? That as far forward as I believe I have seen. 45" seems to be the ballpark I've seen for 10" trailers. Perhaps because of a light galley and heavy nose (batteries, front storage box, etc?

[Eddielbs]

Thank you for the input.. The Axle placement is the only thing I'm still questioning. Like Larry I too will be pulling my tear with a jeep off road from time to time. That is the reason I'm going to keep the cross members. But more importantly the axle placement. I chose 52" due to the fact I plan on having a Box with an AC and heating unit from the Lil guy site.( http://www.golittleguy.com/shop/index.php?productID=19 ) in the front along with a honda generator like this one. ( http://www.hondapowerequipment.com/ModelDetail.asp?ModelName=EU1000i ) That would be placing and Extra 80 lbs on the front 50 for the AC and 30 for the generator. I also plan on having an Ice chest, batteries and a water tank in the Galley so I came up with 52" on the axle to try and help with the hitch weight.. I'm open to suggestions in this area because in no way am I an expert on the subject...

[bobhenry]

I'm no off road expert I don't even like gravel roads . Just a couple thoughts if you get into situations with short choppy hills and gullies are you taking a chance of tail bashing with the tires so far forward. I used the 60 40 rule and put the axle of my 10' at 48" from the rear ( 120" x 40% = 48") and it tends to dance at highway speeds above 65 mph. I wish I had gone to 40 or 42" I think it would have helped. So a longer tongue is in store this summer.

[angib]

I'm surprised for such a heavy frame that you're only using a 30" tongue - you could go up to 36" at least.

Unlike Rocky (asianflava), I like the diagonals as they take some load directly from the coupler to where it's going, the side rails. It also makes building a secure base for a tongue box easy.

With 3" tube tongue onto a 2" tube frame, the two cross-members holding the tongue need to be well apart (just as you have shown them), otherwise they will fail before the tongue does.

52" does seem a long way forward for the axle. You say you're planning to add ice chest, batteries and water tank to the galley and they weigh a lot, so you won't have a light galley. OK, you will have a good load on the front from the AC, heater and genny, but at a first guess I'd say those only cancel out the stuff in the galley.

With so many heavy weights, you would be better to use my spreadsheet - one weight for the trailer frame/body, one extra for the stuff in the galley and one more extra for the stuff up front. I'll be surprised if you get more than 44-48" as an optimum. If you want help with it, send me the figures.

Andrew

[angib]

I wish I had gone to 40 or 42" I think it would have helped. So a longer tongue is in store this summer.

Sadly, making the tongue longer will make very little difference to the balance. And lengthening the tongue makes the tongue weight go down, which is the opposite of what you want.

Really, you need to move either the axle back or the centre of gravity forward - like by shifting weights forward.

Andrew

[bobhenry]

But ... But ....But.... I'll have room for a tongue box to throw in an a/c unit and a battery and a bunch of other junk you should be able to do without when " roughing it "

[Eddielbs]

Ok so I found the spreadsheet on Angib's Site I changed the Hitch to 50" and filled in the blanks... With the weights and measurements I'm entering with the axle set at 48" I should have 10% on the hitch weight and that adds up to be 190 lbs with 830 lbs on each wheel.. I think thats a lot better than the Axle at 52" and the hitch weight of 7% Thanks a lot for the info and the WAY Cool spreadsheet (':thumbsup:')

[asianflava]

If you are mounting stuff on the tongue (you didn't say that in the initial post) then keep the diagonals . Mounting a box to a single tube will not be very secure.

Also, if you are using it offroad (also not mentioned in your initial post) then a leaf spring axle would be a better choice than a torsion setup.

[Esteban]

You could probably use 2"x3" rectangular tube, instead of 3"x3", for your tongue. The diagonals will give it extra horizontal strength and also help to support your Pet Cool and generator.

Didn't Larry Sorenson build his teardrop entirely on top of the frame, without the side walls covering the the trailer frame, so the side walls would be better protected from getting damaged from off road use? It might be a design consideration to keep in mind to have enough room for your chosen bed width.

Looking again at your plan it looks like you're using a spring axle, not a torsion axle. Are you going to use shocks too? If so, plan for a way to attach them.