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PowerHelis . JR-Spektrum . Gyro Hobbies

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CAD - Engineering - Technical > Need help fast from engineers
 
 
helicopter34
Veteran
Location: New Jersey, exit 82

I am currently part of a college team designing and building a human powered vehicle. Its basically a recumbant bike with a roll cage. We have the frame built and our design is for 1 wheel that powers the back and then two wheels in the front that steer. My question is we need to design and build something to allow the front two wheels to pivot for steering. Everything is made of aluminum so far and I was telling the other member that an aluminum on aluminum bearing would never work. I plan on making caps out of some material like nylon or something and sleeves that these caps sit in so that you have nylon on nylon rubbing.

My question is what material should I use for making these sleeves, like teflon or something. Anyone know where we can order something like this. We need it in small chunk so we can machine it.

Make it idiot-proof, and someone will make a better idiot
03-02-2004 Over year old.
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Sar
Elite Veteran
Location: Kingston, NY

If you find out which material you need, try these guys for a source, they have a lot of variety from raw materials, to components such as bearings, bushing, chain drives, pneumatics, etc.

http://www.smallparts.com/

--
Jon
03-02-2004 Over year old.
HOMEPAGE  
 
 
Ozzy Pilot
Senior Heliman
Location: Victoria, Australia

Hi I would look at options such as sintered bronze bushes these are readily available from any bearing shop. The bush could simply be press fit into an outer support.

There are other materials also such as Ultra high molecular weight polyethylene. UHMWPE for short, this is not as precision as say a sintered bush.

By the way the sintered bush is generally self lubricating as it has lubricants impregneted into the bronze.

Hope this help

Member of Good Guy list (seller) Pg. 23. Turbines - Audile pleasuring
03-03-2004 Over year old.
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helicopter34
Veteran
Location: New Jersey, exit 82

Place to order

Do you know about a place that would be good to order sintered bushings.

Make it idiot-proof, and someone will make a better idiot
03-03-2004 Over year old.
HOMEPAGE  
 
 
JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

www.mcmaster.com has all kinds of stuff.

Thanks, John Cadwell
03-03-2004 Over year old.
 
 
DTM
Senior Heliman
Location: Belgium

why dont you use a ball bearing? If you want to keep everything slopfree, you'll need more than bushings. I worked in a specialist mountainbike shop and I can tell you those pivot points suffer a lot. It's not so much the wear from the pivoting but the impacts you get from riding the thing.
I'd use a Aheadset system with needle bearings which is commercially available.
03-03-2004 Over year old.
 
 
mathew10
Heliman
Location: UK

try contacting one of the HPV (human powered vehicles) forums or orginasations such as http://www.ihpva.org these guys are always building similar things
03-03-2004 Over year old.
 
 
rover
Senior Heliman
Location: Brandon,FL

Aluminum to aluminum bearing wont work it has Coeffecient of mu=1.3 Too damn high. sintered brass would work great. also a machined teflon type bearing would work good.

Rover
Mechanical Engineer
03-04-2004 Over year old.
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HelicopterJohn
Key Veteran
Location: Seffner, Florida (Just East of Tampa, Florida)

Flying

Hi Rover,

Are you back flying or still hitting the books for that degree?



OC Bob's Gathering #2 was a Premiere Event. Pictures in my Gallery
03-04-2004 Over year old.
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JBajkor
Heliman
Location: Hamilton, Ont. Canada

Delrin should work fine.
Check out the mechanical properties here:
http://www.alro.com/plastic_product_delrin.htm
Joe
03-05-2004 Over year old.
HOMEPAGE  
 
 
HelicopterJohn
Key Veteran
Location: Seffner, Florida (Just East of Tampa, Florida)

Design on stem for steering

helicopter34

"Not an engineer" but I have a question? What material do you intend to make the stem/spindle from that contacts the bearings and or bushings and provides steering? I would think this would have to be of a material that is hard and withstand the "HARSH" shock loads "DTM" described in his experience in the mountain bike shop.

"DTM' had mentioned using ball bearings. You maybe could even use Timken taper roller bearings which could be adjusted for slop as time goes on if properly designed.

Good Luck,

P.S. Are you allow to post any pictures? I understand if being done for a grade and you don't want others to see until finished.



OC Bob's Gathering #2 was a Premiere Event. Pictures in my Gallery
03-05-2004 Over year old.
HOMEPAGE  
 
 
rover
Senior Heliman
Location: Brandon,FL

John,
I am still working hard for my degree, only 8 more engineerng classes left.

Rover
Mechanical Engineer
03-05-2004 Over year old.
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HelicopterJohn
Key Veteran
Location: Seffner, Florida (Just East of Tampa, Florida)

Education

Rover,

Keep up the good work. We are all proud of your accomplishments. When those big paychecks start coming you will have plenty of time for the R/C Helicopter Hobby/Sport.


OC Bob's Gathering #2 was a Premiere Event. Pictures in my Gallery
03-05-2004 Over year old.
HOMEPAGE  
 
 
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