The Worst Ducati in Dallas

rentedshoes

New Member
Time for another update.




Those wit a keen eye will recognize this as the Radical Ducati seat from previous posts. I managed to track down Yann in France and had him make this up. I plan to remake this from carbon fiber using this one to make a mold. Of course there was a bit of a language barrier to overcome. He asked if I wanted the additional "mount" (thanks google translate) and of course, I did. I really thought that a proper mount for this was too good to be true but if he had it why not? Turns out that he meant seat pan for upholstering. Since there is zero chance of this fitting the stock subframe, I am going to be crafting that as well. In a perfect world, I'd make a one piece seat/subframe. We're just gonna have to see how things turn out.
 

rentedshoes

New Member
I think the days for quick progress are behind me. Now is the time of year to wear my fingerprints down so that my phone doesn't recognize me.

The big question is how does the seat fit?

I'll go with reasonably well. There will need to be some tweaks here and there but ultimately it is the aesthetic I was after. I spent much of the day prototyping a subframe. The lines I want look as if they will work but time will tell. The overall arc works as prescribed. And with any luck, the lines for the subframe will land parallel to an existing line.


While I was waiting for the subframe prototype to cure, I took to polishing some parts. I put a shine on the rear sprocket carrier and the intake trumpets. These will either be further polished and/or anodized.

 

rentedshoes

New Member
Ok, in this update I'm gonna ask for a little help. I'd like to think that I have a better than average understanding of composite materials but I'm moving into uncharted waters here. I do not question one bit that I can make some composite parts that are absolutely beautiful and will look great on a show floor. However, showing is only job 1 for this bike. I fully intend to ride the wheels off it. So, it has to be strong. Nobody wants to hit their ass on a rear tire at speed.

So, I am asking for help and suggestions about the subframe design I m working on. At this point I plan to remanufacture the Radical Ducati seat from Carbon Fiber. During this process, I have the option to combine the subframe with the seat making a monocoque design. Besides rider weight, the structure will need to support the ECU and an Antigravity battery. To say this is an important piece is the understatement of the year. I mean, I've crashed this bike once...Let't hope that was the one and only.

K. Here's where I'm headed. Please no jokes, PVC pipe was the nearest analog to the carbon tubes I plan to use.


This picture shows the lines of the fame that I intend to continue. The subframe tubes will be notched to but together perfectly before being bonded and wrapped with reinforcing fibers creating a (what I hope) is a solid junction.


This next picture shows another angle of the proposed layout. I am wondering if I need to add supports at the points in which the subframe mounts to the frame and if a gusset will necessary at the angled junction at the back of the subframe.

I'll reiterate that I plan to bond the seat to the subframe and create a monocoque structure if I can figure how to fit all the necessary parts inside.

So, any input from the group? Also, if there is anybody local with good knowledge of carbon/composite manufacturing in the DFW area that is willing to come help, I've got Dallas Blonde on tap.
 

teazer

Active Member
DTT BOTM WINNER
Check out the Aprilia RS125R and the 250 twins for ideas on a seat /subframe made from C/F. 125 was skinny at the front - maybe 60mm wide plus two side bolts. RSV250R was like the cup bikes except that there was no aluminum subframe hiding inside it. Check with Micah at AF1 in Austin, he may have some pictures on file somewhere.

Basically the 250 seat was attached at two points on each side like the subframe and I think it included honeycomb to add three dimensionality. You need torsional rigidity.
 

DesmoDog

Member
IMHO if you are going to use composite materials, design the piece to take advantage of the material. Don't just copy round tubes. Take teazer's advice and look at how other companies are doing it.
 

rentedshoes

New Member
Thanks for the feedback Teazer and DesmoDog. I have taken it to heart. After staring at the bike and researching carbon sub-frames and monocoque tail sections, I agree that I was headed down the wrong path. I think I can do better. The trick is the make the thing strong enough and keep the aesthetic.




At this point, this is the look I want. I still think the tubular support of the tail is key to the look of the bike. Also, I really like the idea of using all four of the stock mounting points. However, the more I think on this, the more I question it.



I suppose that I could use all four stock mounts and ditch the tubular supports using a mounting design like the one pictured above. I’m just not sure this bike will look correct with a floating tail. I think that you guys are right that with the correct layup the tail should be plenty strong and not need a more traditional skeleton.


I guess all that’s left now is to try a couple of things and see what works.
 
the sb6 had a carbon rear section, and it was basically an inverted u section. typically of any material flanged edges and curves should help it strength wise.
 

rentedshoes

New Member
I've been playing with some designs and prototyping a little over the holiday. I decided to play with some ABS plastic to get some shapes that I can eventually build a mold from. I figured an ABS laminate would more mimic what is possible with composites than plastic tubes. While these are very crude, I think they will pave the way for the final design. I think if I correctly integrate a "U" shape as suggested by Brad I can get the desired structure. Admittedly, this is simply the first step in the monocoque development. Dare I ask for feedback?





 

teazer

Active Member
DTT BOTM WINNER
You have the right idea. Maybe even slicker if you could drape the shape outside of those lugs with mounts dimpled in and alloy spacers inside the lugs for a more streamlined look or leave them where they are for a more bare bones look.
 

rentedshoes

New Member
teazer said:
You have the right idea. Maybe even slicker if you could drape the shape outside of those lugs with mounts dimpled in and alloy spacers inside the lugs for a more streamlined look or leave them where they are for a more bare bones look.
I'm not exactly sure what you are saying here. :(
 

teazer

Active Member
DTT BOTM WINNER
rentedshoes said:
I'm not exactly sure what you are saying here. :(
http://raresportbikesforsale.com/wp-content/uploads/2015/05/20150516-1999-aprilia-rs250-cup-left-730x488.jpg

http://tyga-performance.com/images/thumbs/1800_1200/apseat3-209f972e.jpg

http://www.apriliaforum.com/forums/attachment.php?attachmentid=167375&stc=1&d=1311687275

http://i.imgur.com/Ik1oDXz.jpg

http://www.iane.co.uk/store/images/source/Speedfiber/RSW250_007_ON_/17428_RSW_250_07_ON_SEAT_1.JPG

https://ultimatemotorcycling.com/wp-content/uploads/2016/12/2017-aprilia-rsv4-fw-gp-250-horsepower-1.jpg

http://www.sportbikerider.us/Pics38/1999-Aprilia-RSW250-203859.jpg

What I was trying to say was that the seat has to have sufficient dimensionality in all three planes to be stiff enough. One way is to have the seat "sides" go around the outside of those lugs. Then indent the mounting bolt holes so that the hardware is below, or level with, the surface. None of those examples are exactly what I had in mind but all have elements of the design.
 

rentedshoes

New Member
So, a lack of updates does not mean there hasn’t been progress. There has been the normal polishing and surfacing and collecting of parts. However, the tail section is what has been preventing any real forward progress. As you may recall, this is about where we left off. That picture makes the tail look very visually heavy. It's really not.


I figured there were enough pictures and videos of people making molds and generally tinkering with fiberglass. I figured I’d spare you that process. The cliff notes are that you need to use tons of mold release and that you’ll never get back complex curves that are messed up in a mold. Mold #1 went to the landfill and mold #2 was a reasonable success. It isn’t much to look at but there was an absolute mountain of hours that went into making that stupid thing.


Yesterday I finally got the courage and materials to attempt MK1 home made carbon seat outer skin. It went reasonably well. The end product parted easily from the mold but left me disappointed. There were far more voids than I would have liked. However, without a vacuum bag or bladder I think it turned out OK. I’ve got some ideas for MK2 that should circumvent all the issues that this product has.

VOID!


On the shopping list is potentially a vacuum bag or bladder in addition to a roller, a fabric cutter and some wider carbon cloth. 12” wide made for some compromises in layup pattern.

Stay tuned. More as it happens!
 

doc_rot

Oh the usual... I bowl, I drive around...
DTT BOTM WINNER
I use Fiberlay for my stuff, they have the bagging material, and anything else you might need. They have a material called "Strechalon" for bagging that is great for getting in tight compound curves as it will flex unlike the regular plastic bags. They were local to me at one time. They are extremely knowledgeable and have been very helpful to me in my projects in the past so I have continued to use them.
 

rentedshoes

New Member
While I waiting on more composite making stuff to arrive, I decided to turn my focus to the headlight. I knew I wanted to have a round led headlight but I didn’t really want to use a traditional bucket. I don’t think the look suits this build and I’d want to make it from carbon fiber.

I had originally ordered a unit from Trucklite but it didn’t have the mounting options I wanted. So, it went back and I ordered a different led unit meant for a Jeep.


Once it arrived, I drilled and tapped some holes and started taking measurements for a bracket. I wasn’t sure what the final construction would be when I started but I am thinking about 3D printing it from carbon reinforced plastic.

Thank goodness there is so much good freeware out there. It’s truly amazing that A knucklehead like myself can design functional parts in CAD. I wanted an end product that was very clean and basic and could easily go unnoticed until someone really begins to look at the details of the bike. After many, many failed prototypes I settled on this design. It’s simple, easy to produce and will be strong.



Thank you Cura for free slicing software!


And a couple hours later I had these:

Yes, there is still some of the support material to be removed. This final prototype is basic PLA and not quite strong enough for me to be confident in actually using the part.


I decided to use the factory mount on the head-tube. Add in some titanium bolds and you have a headlight mount.





I’m pretty sure that’s all I have for today.
 

The Jimbonaut

Active Member
Man, I'm inspired. I want to muck about with a Ducati next. I'm really enjoying watching your progress mate and your bike is shaping up great.

(Off to Craigslist to look for Ducatis)
 

The Jimbonaut

Active Member
Back from Craigslist. That was humbling. Maybe a trip to Vegas and a night on the craps table? Daddy needs a new pair of shoes!
 

johnu

Active Member
DTT BOTM WINNER
The Jimbonaut said:
Man, I'm inspired. I want to muck about with a Ducati next. I'm really enjoying watching your progress mate and your bike is shaping up great.

(Off to Craigslist to look for Ducatis)
I hope you have plenty of dough:)
 

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