www.recumbents.com - Carp Front End
www.recumbents.com
www.recumbents.com
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
 All Forums
 www.recumbents.com
 Technical / Bike Building
 Carp Front End
 New Topic  Reply to Topic
 Printer Friendly
Previous Page | Next Page
Author Previous Topic Topic Next Topic
Page: of 10

Jerry
human power supergeek

USA
1475 Posts

Posted - 11/15/2015 :  16:49:38  Show Profile  Reply with Quote
Such as zero scrub radius, positive scrub radius, and negative scrub radius? Is that like toe-out and toe-in?
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/15/2015 :  18:23:05  Show Profile  Visit alevand's Homepage  Reply with Quote
quote:
The O.E.C. was an unusual motorcycle, using 'duplex' steering; an OEC trademark, although not all of their bikes used this system. The advantages of this arcane steering system on these early motorcycles was great stability at speed, plus the possibility of front wheel suspension which didn't alter the steering geometry when compressed by bumps, giving totally 'neutral' steering under all conditions. In practical use, the OEC chassis was reported to be very stable indeed, although resistant to steering input! So, while potholes and broken surfaces brought no front wheel deflection, neither did a hard push on the handlebars...perfect for a speed record chassis actually.


http://thevintagent.blogspot.com/2010/10/oec-zenith-and-stolen-record.html






C:
Tony Levand

Edited by - alevand on 11/15/2015 18:25:54
Go to Top of Page

Jerry
human power supergeek

USA
1475 Posts

Posted - 11/15/2015 :  19:18:44  Show Profile  Reply with Quote
Great stuff! Isn't it funny how some innovations get lost? Love looking and reading about those old bikes. I remember some of the names. With my limited intelligence, I think I'll stick with the steering I have for now. Maybe remote steering later, nothing this complex.
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/16/2015 :  13:24:31  Show Profile  Visit alevand's Homepage  Reply with Quote
Its new but oec patented one in 1927...
quote:
Company engineer Fred Wood seems to be the source of OEC’s unorthodox chassis ideas for which they became best known, which includes a swingarm rear suspension with long vertical plunger-type springs housed in the frame tubing, which appeared in 1929.
Two years prior, Wood and OEC introduced the ‘Duplex’ steering system (not really ‘forks’), a visually complicated assembly of parallel tubes, visible on this 1936 machine. The extended front tubes make for an extremely stiff frame, and very stable steering…almost too stable in fact, as the Duplex system could never be credited with being nimble. At speed, the Duplex prefers to self-straighten, meaning it’s incredibly stable, if not particularly agile for corner-carving. In an era of head-shaking and tank-splapping front ends, stability was a coveted chassis quality for riders, and most epecially to speed merchants


Pipe Dream:



http://www.tiermotor.com/Four-Bar%20Steering%20Mechanism.pdf

C:
Tony Levand

Edited by - alevand on 11/16/2015 15:21:11
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/16/2015 :  15:20:48  Show Profile  Visit alevand's Homepage  Reply with Quote
I found out why it was pulling to the right and seemed to do so a little more after the brake test, the cheep fork lost it's temper where I welded the steering arm on it's slightly bent back there. Still seeking a solution the brake n turn feature, maybe there's a better phrase for it, skid steer?

C:
Tony Levand

Edited by - alevand on 11/16/2015 15:31:48
Go to Top of Page

Jerry
human power supergeek

USA
1475 Posts

Posted - 11/16/2015 :  16:09:15  Show Profile  Reply with Quote
The steering on the Tier looks awful fragile to me. Solution for skid steer, retractable parachute! lol
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/16/2015 :  18:19:02  Show Profile  Visit alevand's Homepage  Reply with Quote
No, no parachute, just the opposite, a coroplast fairing.

quote:
Originally posted by Jerry

The steering on the Tier looks awful fragile to me. Solution for skid steer, retractable parachute! lol



C:
Tony Levand
Go to Top of Page

Speedbiker
human power expert

USA
3835 Posts

Posted - 11/16/2015 :  19:35:02  Show Profile  Reply with Quote
Hey Jerry, imagine popping the chute in a crosswind! Weeee!
Go to Top of Page

Balor
recumbent guru

Russia
750 Posts

Posted - 11/17/2015 :  02:59:42  Show Profile  Reply with Quote
quote:
Originally posted by Jerry

The steering on the Tier looks awful fragile to me. Solution for skid steer, retractable parachute! lol



Might as well add retractable wings and forget about turning altogether.
Don't drink and drive - smoke and fly! :D

On a more serious note - would this mechanism work for MBB?
It seems like the best of all worlds!

Edited by - Balor on 11/17/2015 03:00:11
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/17/2015 :  03:26:00  Show Profile  Visit alevand's Homepage  Reply with Quote
When I worked for Mc Donnell Douglas, there was a windshield bird strike test for FAA certification of the MD-11. It was a million dollar test. The whole nose section was flown from Long Beach to St Louis. A live chicken, not frozen, was to be shot out of an air cannon at 400 mph. The FAA changed the requirement to just above the windshield, called the eyebrow. All calculations and analysis shows the bird would bounce off. The chicken was anesthetized and put in an ice cream container, knives at the end of the barrel sliced the carton away as the bird blasted toward the jumbo jet.

Guess what happened.

C:
Tony Levand

Edited by - alevand on 11/17/2015 03:33:17
Go to Top of Page

Jerry
human power supergeek

USA
1475 Posts

Posted - 11/17/2015 :  04:31:18  Show Profile  Reply with Quote
Would disc brakes work better? Or would you still have the skid steer? Sometimes I still use the Fred Flintstone maneuver!

The ballistic chicken broke the windshield, broke the engineers chair, and embedded in the wall!(bulkhead)

Edited by - Jerry on 11/17/2015 04:36:59
Go to Top of Page

shooky56
recumbent guru

USA
545 Posts

Posted - 11/17/2015 :  04:48:28  Show Profile  Reply with Quote
The bird set a new "bird world 200m record", finishing featherless, deaf and exhausted but VERY VERY proud. Stood on the podium and announced, "I'm clean, take a blood test, you'll see.".

What happened Tony?

Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/17/2015 :  16:04:45  Show Profile  Visit alevand's Homepage  Reply with Quote
Well good news the fork is not bent, it was just how the light was reflecting off it. The problem is the ball joint at the top and the links being so close, 7 inches away, that any peculiarities from the virtual pivot steering are magnified fourfold. I am considering lowering the links and removing the little arms welded to the fork and attach directly. It will increase the trail a bit and reduce steering. If I increase trail enough it will counter the steering offset.and thus reduce skid steer. The difficultly is making a hard point on the frame to attach the links. The pedals are on one side and the tire on the other.

Now for the rest of the story,

The bird went right through into the area above the cabin ceiling and outer fuselage skin. If you have ever seen the ceiling in the cabin its a mind boggling array of switches, controls and and instruments. It pushed the ceiling down and everything was hanging by wires with chicken guts and feathers everywhere. It was deemed a success, since the wires were still attached to the dangling switches, the pilots could still operate them and fly the plane. My assignment was to figure out that now there is a ram air scoop with 400 mph air blowing in, would the pressure push the ceiling down onto the pilots heads. The fix, of course was to install a doubler on the eyebrow.



C:
Tony Levand

Edited by - alevand on 11/17/2015 17:49:57
Go to Top of Page

PUGZCAT
recumbent enthusiast

Canada
466 Posts

Posted - 11/17/2015 :  19:08:30  Show Profile  Reply with Quote
To infinity and beyond!
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/24/2015 :  16:57:19  Show Profile  Visit alevand's Homepage  Reply with Quote
http://www.paulcompton.vispa.com/lynch2.htm



https://www.youtube.com/watch?v=YvLdvm3tInA

C:
Tony Levand

Edited by - alevand on 11/24/2015 17:13:49
Go to Top of Page

Jerry
human power supergeek

USA
1475 Posts

Posted - 11/25/2015 :  15:33:07  Show Profile  Reply with Quote
https://www.youtube.com/watch?v=7hRf8yvT87U
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/25/2015 :  17:56:03  Show Profile  Visit alevand's Homepage  Reply with Quote
Thanks Jerry. It took me a while to figure out how the steering works on the Traverson Vrex. It's a leading link suspension similar in principal to this, but with much shallower head angle.:


C:
Tony Levand
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/26/2015 :  09:34:48  Show Profile  Visit alevand's Homepage  Reply with Quote
I put new pivot mounts on the fork half way between the old ones and the axle, made longer links. Trail is 15 inches, with wheel flop but no skid steer. Too miserable out to test ride, but I will go back to the original pivot mounts but longer links and try to find a sweet spot. Putting the links lower on the fork spread the pivot apart from 2.25 inches to 4 inches, thus extending the virtual axis way out front, about to a 45 degree steering axis inclination. Hardly ridable. If the next iteration isn't satisfactory, I may just can the idea and use a normal head tube.

C:
Tony Levand

Edited by - alevand on 11/26/2015 09:37:59
Go to Top of Page

Jerry
human power supergeek

USA
1475 Posts

Posted - 11/26/2015 :  11:54:57  Show Profile  Reply with Quote
I sure hope you get it to work. I was wondering how it would work with the links lower. I didn't see an ideal spot to locate the links any lower than you had them. I just thought the Traverson Vrex was cool looking!
Go to Top of Page

PUGZCAT
recumbent enthusiast

Canada
466 Posts

Posted - 11/26/2015 :  14:56:44  Show Profile  Reply with Quote
A short head tube with a slack angle and fork with the right offset to get 3 inches of trail maybe the ticket to tuck down the fairing.
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/26/2015 :  17:33:50  Show Profile  Visit alevand's Homepage  Reply with Quote
I rode it between rain showers today. Lots of wheel flop. OK once going over 15 mph seems OK going straight at 25 mph, starting and low speed are tough.
I'll cut the links to be slightly longer then the old ones and try it. I may move the upper ball joint forward 2 inches.



lengthened the old links 1 inch on virtual pivot steering, it eliminated skid steer and inverse wheel flop. Steering angle is more restricted, though:

https://youtu.be/kfcpZLRwES4

C:
Tony Levand

Edited by - alevand on 11/27/2015 08:00:39
Go to Top of Page

Runxner
recumbent enthusiast

USA
455 Posts

Posted - 11/27/2015 :  09:14:11  Show Profile  Reply with Quote
Video link is private

Team Low-Life
Lowracer Test Pilot/Evangelist
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/27/2015 :  14:07:38  Show Profile  Visit alevand's Homepage  Reply with Quote
Video should work now. Somehow the seat and BB are now 3 inches lower, 8 and 12.5 inches. Went back to more steering and more skid steer with the truss connection. Can make a circle on a 3 lane road.



quote:
Originally posted by Runxner

Video link is private

Team Low-Life
Lowracer Test Pilot/Evangelist




C:
Tony Levand

Edited by - alevand on 11/27/2015 14:11:44
Go to Top of Page

Jerry
human power supergeek

USA
1475 Posts

Posted - 11/28/2015 :  08:15:27  Show Profile  Reply with Quote
I like the truss connection. Strong.
Go to Top of Page

alevand
human power expert

USA
3541 Posts

Posted - 11/28/2015 :  09:31:44  Show Profile  Visit alevand's Homepage  Reply with Quote
I cut off the small arms on the fork and welded the pivot screw directly. This got rid of the torsional deflection during braking, much stiffer now, but handling is heavy, too much trail, even with the links adjusted back to where the tire rubs. No skid steer. Yes the truss is stiffer, but my toes and tire were hitting during the test ride. I need to move it back for tire clearance and forward for toe clearance. I am thinking of using 1 inch x .035 tubing instead. I can easily ride circles at nearly lock to lock. I need to finish this and move on.

C:
Tony Levand

Edited by - alevand on 11/28/2015 09:32:47
Go to Top of Page
Page: of 10 Previous Topic Topic Next Topic  
Previous Page | Next Page
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
www.recumbents.com © 2019 www.recumbents.com Go To Top Of Page
Snitz Forums 2000