Senior Design: Design and Build a Trailer to be Pulled Behind a FZ6

[bmccrary]

Pictures have been added. Click link for link to facebook pictures. Please continue to read for more info regarding the projects progression

http://www.facebook.com/album.php?ai...6&l=0f2ff3ac1b


Ok so its been a while since I have posted or followed the forum. My apologizes. Its been pretty hectic in my neck of the woods and here is one of the several reasons.

So for my senior design project I have decided to design and build a single wheeled trailer to pulled behind the FZ6. I will be designing the hitch to mount to the motorcycle so that the when it is not in use there is no significant signs of modification to the bike. The trailer is to be able to hold the basic camping supplies for two people. This includes: tent, 2 sleeping bags, 2 folding chairs, cooler (stocked), pillows etc. The trailer is to not hinder the bikes basic (safe) lean angle and should be as light as possible. (Aluminum frame, fiberglass/carbon fiber body.)

Where I am at this point:

The hitch system will be mounted to my GIVI rack. Last Monday I determined the material type of the rack to get its material properties, so all should be in order there. Tabs will be welded to the sides of the rack as close to the points where the rack mounts to the motorcycle. I have the formulas set up for stress and strain. However this will be adjusted once the hitch is drawn up and the angle of bars in the hitch are determined. At this point I need to model the GIVI rack before hitch modeling can begin.

*Side note* If anyone is proficient with SolidWorks or Pro-Engineer and has any tips on Weldments or Variable Section Sweeps I would love to talk to you. As getting an exact model of this rack has proved to be rather challenging.

One the first items completed was the mass and volume calculations for the items to be placed within the trailer. I spent a considerable amount of time with the cooler as it is the single heaviest item and will be my best option when it comes to shifting the load weight. (it will be able to fit sideways in the trailer) After it was all said and done I came up with a total load of 85 pounds (cooler and gear). In addition the trailer weight should hopefully be no more that 150 lbs. So that gives me a total trailer weight of 235 lbs. (Hopefully) After finding the theoretical COM and CG the trailer will need to be around 84 inches long to keep the tongue load around 30 lbs. I want the max tongue load to be no more than 50 lbs. The cargo dimensions are approximately 48" long x 22" wide x 20" tall.

After determining a safe lean angle of 55 degrees I found the minimum trailer height to be 8 inches from the ground based upon the 22" wide number.

Electrical. The trailer will have a brake light, turn signals, tag light, and two side markers which will act as turn signals as well. With the bikes output of 310 watts and the 240 draw from the factory that gives me 70 to play with.
My J&M intercom pulls roughly 7 watts then another 10w from the pod lights. Which leaves me 53.78 watts when I am not running my high beam....I only have 14 available when that high beam is on. (100/55) I like to light things up! I found a company that is dedicated to LED stuff and I am able to get some nice 13 bulb wide angle set ups that will in total only draw 15 watts. Also, these LED set ups are dual circuit so the will have a bright and dim setting. (running/brake/signal)

Acceleration rates... hehe this was fun the first time around. Using the accelerometer on an iPone I played around and did some 60 to 0 runs as well as some 0 to 70+ runs... that data didnt turn out too well so I went the boring route (formulas) and got some better data. Turns out in first gear our max acceleration is 11.377m/s^2 and when braking we can decel at 10.17 m/s^2! Kinda cool! These values were needed in order to determine the forces on the hitch and connection point. Multiply acceleration by mass(trailer) and you get a force...

With the increased load due to the trailer and riding two up with gear the rear shock will not suffice. Heck it doesn't work that great now... so thankfully I have some connections at Ohlins...need I say more. Other than that I will be doing motion ration calculations in the near future to determine the exact spring rate and damping coefficient needed. More on that later.

Yesterday I spent some time calculating the COM and CG of the bike so I could compare it to that of the trailer. The concern being that with a single wheeled trailer the weight of the trailer could potentially pull the bike over in a lean. So once I had the location of the CG I was able to calculate the MMI and calculate it for the trailer as well and determine a ratio. At this point its around 11% which is fine... no real influence. And those values were of just me, no luggage or passenger. So that ratio will greatly decrease with those added (More on that later) See link for more info on calculating CG and such of the bike.
http://www.fz6-forum.com/forum/fz6-t...alculated.html (FZ6 Center of Gravity Calculated!)

Now I havent really clarified how the trailer will be connected to the hitch. I am going to use a universal joint so that the trailer will be able to move up and down and side to side (tight turning) More info will come later on forces on that joint.

As far as the trailer is concerned. I am thinking of constructing it out of aluminum box tubing. In addition the trailer will have its own suspension, very similar to the bikes set up. Small swing arm with a linkage less shock set up.

Next week I have meeting with my old dynamics professor to do some calculations regarding the suspension dynamics of this set up. Should get interesting!

So that in a nut shell, along with my other class work is what I have been this fall. Unfortunately I have till the first of December to finish the design. (calculations, solid model, BOM and budget). Then next semester is the build...

With that note I need to find a local machinist that would be willing to weld this chassis together. Hopefully for a very low cost... so if anyone knows any welders/machinists in the Charlotte (ish) area. That would be great, too.

So that is roughly were I am at right now. Just thought I would share this with you all, and I will try to update this as more is determined and drawn up...I am finding out alot of neat stuff regarding the dynamics of the FZ in the process, so that is pretty cool I think.

More to come...

For more info regarding single wheeled trailers and how they work. Look up the Uni-Go trailer or the 3rd wheel trailers....

-bryan

[FZ1inNH]

Bryan, what an awesome project! High kudos for taking it on and I can't wait to see progress and product!

[Ozfazer6]

I owned a trailer for many years,they a great behind a bike once you get used to them.
Designing one from scratch............awesome

[04fizzer]

What's your reasoning behind attaching to the GIVI mount, rather than something like the swingarm? I would think that the suspension working, and the ditsance it travels, could cause a problem with the trailer bouncing.

[mstewar1]

Great project. It'll be cool to watch this progress.

So what's the machine/work shop like at school..?

[Ozfazer6]

Originally Posted by 04fizzer

What's your reasoning behind attaching to the GIVI mount, rather than something like the swingarm? I would think that the suspension working, and the ditsance it travels, could cause a problem with the trailer bouncing.

You don't attach to the swingarm ,you need a rigid mount and cross linked suspension on the trailer .
My trailer also had a 360 degree universal type joint as it's hitch,if it wasn't for the wires for the lights you could pick it up and spin it completely while still attached to the bike.
Attaching to the swingarm would not make for a pleasant ride.

[bmccrary]

Originally Posted by Ozfazer6

You don't attach to the swingarm ,you need a rigid mount and cross linked suspension on the trailer .
My trailer also had a 360 degree universal type joint as it's hitch,if it wasn't for the wires for the lights you could pick it up and spin it completely while still attached to the bike.
Attaching to the swingarm would not make for a pleasant ride.

That and you are in essence adding a tremendous amount of un-sprung weight. In theory the trailer could potentially buck the bike...

Third wheel trailers uses this idea and it seems to work for them, but the dynamics scares me a bit to be honest. My original idea was to mount to the swing arm but then decided against that.

-bryan

[bmccrary]

Originally Posted by mstewar1

Great project. It'll be cool to watch this progress.

So what's the machine/work shop like at school..?

We have some nice stuff for machining. Several multi axis CNC's. Haas's and Makino's. In addition to the standard bridgeports and such. In the motorsports lab we have a blueco (spelling) table for welding chassis stuff. However the one guy who knows how to weld aluminum well is always swamped...so it would be in best interest to take it out side the school to have it done if I want it completed in time.

-bryan

[04fizzer]

Originally Posted by bmccrary

That and you are in essence adding a tremendous amount of un-sprung weight. In theory the trailer could potentially buck the bike...

Third wheel trailers uses this idea and it seems to work for them, but the dynamics scares me a bit to be honest. My original idea was to mount to the swing arm but then decided against that.

-bryan

I guess there are advantages and disadvantages to both connection points. Maybe make a "bumper" of sorts that mounts at the swing arm pivot, and attach the back half of that to the tail section somewhere. Granted, what you're doing is similar to that approach. (I'm not trying to change your mind on what you're doing, I'm just thinking out loud to myself on a public forum)

[bmccrary]

Originally Posted by 04fizzer

I guess there are advantages and disadvantages to both connection points. Maybe make a "bumper" of sorts that mounts at the swing arm pivot, and attach the back half of that to the tail section somewhere. Granted, what you're doing is similar to that approach. (I'm not trying to change your mind on what you're doing, I'm just thinking out loud to myself on a public forum)

Its all good! Thanks for the communication though. That kinda stuff actually helps the design process.

-bryan