Grumman 2 in design library, W&B questions.

[G-force]

I'm building one very similar to the plans in the design library, the only large differences is external , non-recessed wheels. Using the weight and balance Excel program, I am getting a tongue weight of 17.8% assuming the trailer is 1000 pounds. Does that seem right? I am shooting for 10 to 15% and was hoping to also mount the spare tire verticaly up on the tounge. However, that extra 50 pounds brings the hitch weight above 20% which I think is excessive. It will take 160 pounds in the galley to bring it back down to 15%...possable with my battery, charger, a full cooler and some other assorted dead weight, however towing empty will have the hitch weight at nearly 19% assuming the 50 pound battery that stays in the galley. Am I missing something here, or is the 42" axle placement in the designs too rearward for anybody not planning on a decked out, 200 pound galley? The door location prevents the axle from being moved forward to where I feel it should be, 46-50 inches. My walls are already built so its too late for me to move the door forward, but doing it over, I would move it 2-4" forwards to get the axle at least to 46-48". As it stands, I will probally leave the spare off the tongue and put the axle at 44", as close as I can comfortably get it to the door and leave room for a fender. Anybody have a completed Grumman 2 and can comment on the W&B numbers you have experienced? Thanks.

Mike

[angib]

Now I feel guilty. When I copied the Grumman design, I left the wheel just where it was on the photo and, yeah, at 35% of the body length from the back, it's well back. Not extreme for a teardrop (a Cabin Car is under 30%), but better suited to a heavy galley and nothing on the tongue.

So you do need to squeeze the axle as far forwards as possible and plan to put anything heavy in the galley.

Andrew

[G-force]

Hey, I can't complain, I'm getting what I paid for I do appriciate the work you have put onto the library, I just wanted to make sure I wasnt missing something, and perhaps help somone else who builds a Grumman 2 in the future. Anyways, according to my measurments, you can push the axle forward to 44" from the rear of the frame (46 1/8" from the rear of the body) and still leave room for a fender. So thats what I did, axle got mounted today, hope to test fit the floor and walls next weekend.

Mike

[justme256]

Guys,

Thanks for the feedback. I did some further exploring at work today. Stretching the trailer frame looks easy enough. Actually took the frame apart and moved the center cross rails to the sides tonite. Now just need to drill some new holes. I do know somebody at work who does welding. I will consider getting the frame welded to make it more stable.

Thanks for correcting me on the balance spreadsheet. I was thinking of trailer weight as being just the weight of the frame.

Mike, I did come across your thread where Andrew corrected himself on axel placement for the Grumman design. Looks like I need to be more following your axel placement.
Since I will be building at 5” wide around the wheels I need to get this axel placement correct before I start fabbing the floor. There is no moving the wheels after the floor is bolted down.

I ordered A Uhaul hitch tonite for Karens Jeep. Should be here in a week.

I got the Harbor Freight sales flyer today. They are running a sidewalk special this coming Fri, Sat and Sunday. The Haulmaster 2-1/4 ton stabilizer jacks are $17.93.
Does anybody have any experience with these? Should I be putting four jacks on the HF frame or can I get buy with two? The price seems right. Will probably get four. Guess I’ll take some time off work Fri morning and be sitting in the parking lot at 0700!!
Yes its great having a HF only five miles away!

Thanks for your feedback!

Larry

[sschevel]

Looking over the plans and asked the wife which profile she liked and of course it was the Grumman.
Reading more about it and I see concerns about where the wheel should be placed......

Did anyone settle the distance to the center of the axle or does anyone know if the plans on the Grumman 2 correct as they appear here?

Thank you
Guy

[roboconnell]

Hey, I can't complain, I'm getting what I paid for I do appriciate the work you have put onto the library, I just wanted to make sure I wasnt missing something, and perhaps help somone else who builds a Grumman 2 in the future. Anyways, according to my measurments, you can push the axle forward to 44" from the rear of the frame (46 1/8" from the rear of the body) and still leave room for a fender. So thats what I did, axle got mounted today, hope to test fit the floor and walls next weekend.
Mike

To answer previous question the current drawings have the wheel at 39" from the back, with 106" trailer bed that's ~36% from the back - so looks like the design is the same.

So I'm now curious if moving forward to 44" worked out well for Mike. This Grumman design is beautiful and I'm zeroing in on this design for my first teardrop.

Rob

[angib]

To answer previous question the current drawings have the wheel at 39" from the back, with 106" trailer bed that's ~36% from the back - so looks like the design is the same.

I only use measurements from the back of the body, not the frame - with the different designs of the back of different teardrops, using measurements to the frame means you can't compare the results.

Andrew

[roboconnell]

Thanks Andrew - very nice drawings by the way - what a great library!