HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Blog NEW Articles FAQ Contact About




Post new topic Reply to topic  [ 81 posts ] 
Go to page 1, 2, 3, 4, 5, 6  Next
Author Message
 Post subject: Custom aero carbon DIY
PostPosted: Wed Feb 18, 2015 3:44 am 
Offline

Joined: Sun Dec 19, 2010 4:24 am
Posts: 190
Location: Ann Arbor, Michigan
Hi WW,

I've been lurking here for forever, decided it was finally time to share my project with you all! I'm currently a Mechanical Engineering student at the University of Michigan, and my friend (Aerodynamicist/graduate student) and I decided that it would be cool to try to design a cutting-edge aerodynamic bike. Since we're around the same height, we designed a geometry to split the difference and hit it with all the aero tech we could think of. I designed the layup schedule and the manufacturing plan, and after about 8 months of redesigns and optimizations, we are about three weeks away from riding completed bikes!

According to our CFD, we are within 2 watts of a Cervelo S5. Once the frame is done, we will be going to the wind tunnel to validate those claims.

One of the more interesting aspects of our design is it's flexibility-- we can produce a monocoque frame with almost any stack/reach measurement for a total material cost of ~USD$850, plus labor and machining.

Here are some pics, enjoy! Please ask questions, I love to talk about the bike :)

Image
initial CAD model in NX- under BB brakes, designed for 3T funda fork integration at headtube
Image
Cutting the NDS half of the clamshell
Image
Seatstay/chainstay moulds
Image
Finished clamshells. Just gotta gel-coat and wax
Image
Incomplete frame jig (gotta get parts made first!!) :lol:
Image
Seat layup-- not pretty but works like a charm :)
Image
Straight out of the mould
Image
Little bit of trimming-- more to come


Top
 Profile  
 
 Post subject: Custom aero carbon DIY
Posted: Wed Feb 18, 2015 3:44 am 


Top
  
 
PostPosted: Wed Feb 18, 2015 4:29 am 
Offline

Joined: Sun Jan 09, 2011 2:35 am
Posts: 100
Great Stefano! Can you describe the flexibility in the design to enable different sizes?

_________________
Pro-Lite Cuneo


Last edited by FilmAt11 on Wed Feb 18, 2015 7:52 pm, edited 1 time in total.

Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 6:11 am 
Offline

Joined: Sun Feb 22, 2009 12:31 pm
Posts: 47
Location: Brisbane, Australia
Keen to see how this turns out!

I'm guessing you didn't worry about meeting UCI 3:1 etc. with this design?


Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 9:19 am 
Offline
Formerly known as wassertreter

Joined: Tue Apr 12, 2011 8:08 am
Posts: 2154
Location: Pedal Square
Stefano wrote:
According to our CFD, we are within 2 watts of a Cervelo S5.

That's cool.
Can you share more details maybe? Did you do CFD with a rider (assuming complete bike, not just frame at the very least)? What's the yaw distribution for the simulation?
Thanks.

_________________
Bikes: Raw Ti, 650b flatbar CX


Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 12:43 pm 
Offline

Joined: Wed Jan 22, 2014 11:48 am
Posts: 484
Awesome!

More/better pics would be great too.

_________________
Carbon is real.


Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 1:30 pm 
Offline
User avatar

Joined: Wed Dec 24, 2014 2:38 pm
Posts: 101
Great project, keep it coming!


Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 3:20 pm 
Offline

Joined: Tue Jan 28, 2014 12:13 am
Posts: 15
Hi, seems like a great project, very intrigued,
could you post larger photos please?


Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 6:35 pm 
Offline

Joined: Sun Dec 19, 2010 4:24 am
Posts: 190
Location: Ann Arbor, Michigan
Glad to hear everybody is interested! I'll try to answer all your questions as directly as possible, let me know if you don't agree with/understand something!

@FilmAt11: In order to make different sizes, we will machine completely new clamshells for the main frame. The way we constrained the airfoil and tube shapes in CAD allows us to simply enter different stack and reach parameters, convert into a tool-path, and cut out of a proprietary (not metal or tooling board) material combination and gelcoat system. The materials we are using are about 10x cheaper than high density tooling board, and in our testing were able to withstand similar usage cycles as long as the finish was polished to class A. The chainstays and seatstays remain the same shape, and if we ever did go to full production, we would machine those moulds out of aluminum.

@TomHelly: We actually designed this frame SPECIFICALLY for UCI tube shape restrictions. This is compliant with all of the UCI's guidelines on frame shape.

@HillRPete: I can't share too many details! :lol: But here are a few. We ran from 0-15 degrees of yaw, optimized around ~7 degrees (pretty standard in the industry). Our simulations didn't have a rider per-se, we had the boundary condition equivalent of legs, butt, and arms (along with wheels and the rest of the components). We also included two size large bottles in the simulation.

As for more/better pics, I don't have a very good camera but I will see what I can do for you guys :) This weekend we will do a lot of work, I will post more updates/pics then!!

Keep the questions coming, thanks for all of your kind words :)


Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 7:40 pm 
Offline

Joined: Tue Sep 11, 2012 6:07 pm
Posts: 831
Location: The Lone Star State
I love the ingenuity. I can't wait to see the progress of the build. Now, can you provide some more technical details? What BB standard did you decide to use? What wheels did you design the frame around? Is the frame designed for both mechanical and electronic shifting?

_________________
Trek Crockett, Madone, Superfly, SpeedConcept & Cobia


Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 8:39 pm 
Offline
User avatar

Joined: Thu Nov 10, 2005 5:31 pm
Posts: 3473
Location: Surrey B.C. Canada
I can't wait to see this build.

_________________
BIG DADDY B FLOW
AERO & LIGHT is RIGHT

Cervelo SLC 5960g/13.13 lbs


Top
 Profile  
 
PostPosted: Wed Feb 18, 2015 9:07 pm 
Offline

Joined: Wed Apr 22, 2009 4:46 pm
Posts: 132
Hi stefan,

Super cool project. I'm a Msc student Aerospace materials and structures myself at the TU Delft. Would love to start a project like this one day as well!
Keep up the good work at keep us posted! Really interested in what techniques and software you used for the design!


Top
 Profile  
 
PostPosted: Thu Feb 19, 2015 9:47 am 
Offline
User avatar

Joined: Tue Oct 04, 2011 5:04 pm
Posts: 197
Awesome work!

I can't wait to see the build photo's. How are you managing the tolerances of things like bottom bracket and headset?

_________________
Ride it like you stole it


Top
 Profile  
 
PostPosted: Thu Feb 19, 2015 6:19 pm 
Offline

Joined: Sun Dec 19, 2010 4:24 am
Posts: 190
Location: Ann Arbor, Michigan
@FIJIGabe: We are using a 68mm english threaded BB for this build, although we could do BB30 too pretty easily. Threaded has wider tolerances though so it's easier for a first attempt! The wheels we used in the simulation were just boundary conditions for what lower-level CFD predicted the airflow would look like off of 50mm v-shape. If we ran spinning wheels with frame and rider, we would still be on our first simulation :lol: Frame is designed primarily for electric, but I'm putting mechanical on mine. Should be easy, turn out a few cable stops on the mill and boom :) Routing is behind the headtube.

@BmanX: Thanks!! That means a lot-- your and professor chaos' cervelo builds are an inspiration and beautiful :) it's from there that I got the idea to combine the seat with the seatpost all in one.

@MattBeOne: Cool! Glad you like it. If you ever do decide to do a project like this, PM me and I can give more advice/ pitfalls that I struggled with. Software- NX, Catia, SolidWorks, Rhino for CAD, plus all the CFD software we used. Initial airfoil shapes were narrowed down/drawn in xfoil, but I'm not supposed to talk about the rest of the design process.

@Tomstr: They're coming! I'm headed to the shop in 30 mins to do some work, should have some meaningful progress by this weekend. The way we are managing BB tolerances is a machined seat in the mold that cups the BB. It has a hole in both sides that allows a little angular play, which we will take up with a bolt-through centering mechanism of my own design. For the headtube, I am grinding down a thin aluminum tube which will set the bearing seats exactly in the right place relative to each other, again using the bolt mechanism. Eventually this could be made of CF, or omitted entirely.

Thanks again for all your questions, keep them coming! I will do my best to get better pics and will report back soon :)


Top
 Profile  
 
PostPosted: Thu Feb 19, 2015 6:41 pm 
Offline

Joined: Fri Oct 28, 2011 3:25 am
Posts: 1017
Location: United Kingdom of Great Britain and Northern Ireland
So what's the seat angle and what's the head angle? And presumably these are fixed and do not vary if you make frames with differing stack/reach.


Top
 Profile  
 
PostPosted: Thu Feb 19, 2015 6:51 pm 
Offline

Joined: Mon Oct 10, 2011 8:34 pm
Posts: 63
Awesome project. Go Blue! Class of (shudder) 2001

_________________
2014 Cervélo S2


Top
 Profile  
 
Posted: Thu Feb 19, 2015 6:51 pm 


Top
  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 81 posts ] 
Go to page 1, 2, 3, 4, 5, 6  Next


Who is online

Users browsing this forum: BernieV, gambit, Google Adsense [Bot], JAHLIVE4EVER, Rondje, TimmS and 22 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Attachment(s) Top custom carbon frame builders?

[ Go to page: 1, 2, 3 ]

in Road

RedRacer

35

3662

Fri Oct 03, 2014 10:45 pm

nicrump View the latest post

There are no new unread posts for this topic. Any experience with Zipp SL-70 Aero Carbon Handlebar?

in Road

tranzformer

5

1104

Wed Jul 16, 2014 4:14 am

Succisa75 View the latest post

There are no new unread posts for this topic. Bontrager XXX Carbon Aero Handlebars vs Shimano 9000 shifter

in Road

wootenlakeguy

8

1114

Wed Nov 26, 2014 6:48 am

wootenlakeguy View the latest post

There are no new unread posts for this topic. Attachment(s) very rare : Lim. Corima Aero+ Carbon Clincher-Tubeless ready

in For sale - Pictures are mandatory 22-3-13

HOCHPROFIL

0

398

Tue Feb 24, 2015 8:56 am

HOCHPROFIL View the latest post


It is currently Tue Apr 28, 2015 7:39 pm

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB