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 FWD deltra trike 20" wheels how to not rollover?
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ElectricStreamliner
New Member

Australia
68 Posts

Posted - 02/12/2020 :  19:56:23  Show Profile  Reply with Quote




I've been thinking about a front wheel drive delta trike that is as low as possible so the rear wheels can be behind the rider for better aerodynamic.

If I remember correctly it is required that the center of gravity must be below half the track of the vehicle to prevent roll over. With a trike the effective track is within the triangle formed by the front and rear wheels measured at the centre of gravity.

If my centre of gravity is below half of 25cm which is 12.5cm I won't roll over. I can't get that low so my track must increase. Makes sense right?

How would I fix this to prevent roll over without sacrificing aerodynamics?

Edited by - ElectricStreamliner on 02/12/2020 19:59:49

alevand
human power expert

USA
3610 Posts

Posted - 02/13/2020 :  02:28:02  Show Profile  Visit alevand's Homepage  Reply with Quote
You could make it a leaning trike.


C:
Tony Levand
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Balor
recumbent guru

Russia
842 Posts

Posted - 02/13/2020 :  06:02:11  Show Profile  Reply with Quote
quote:
Originally posted by alevand

You could make it a leaning trike.


C:
Tony Levand



Yea, THIS.

Read those articles:
http://lefthandedcyclist.blogspot.com/2015/09/trikes-leaning-trikes-second-look.html
http://lefthandedcyclist.blogspot.com/2018/11/the-optimal-all-weather-ped-electric.html

I am currently making a diamond quad using those principles, preliminary tests of kinematics are encoraging:



http://www.recumbents.com/forums/topic.asp?TOPIC_ID=7484
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Balor
recumbent guru

Russia
842 Posts

Posted - 02/13/2020 :  06:04:27  Show Profile  Reply with Quote
As for velotilt in particular:
http://lefthandedcyclist.blogspot.com/2015/12/the-velotilt-pedal-powered-commuter.html
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ElectricStreamliner
New Member

Australia
68 Posts

Posted - 02/15/2020 :  01:49:13  Show Profile  Reply with Quote
I am trying to decide between tilting trike and landing gear.

Tilting trike
http://www.recumbents.com/wisil/foldracer/foldracer.htm

Landing gear
http://www.recumbents.com/wisil/barracuda/landinggear.htm

I wonder which would be more efficient without falling over.

This would have a fairing which is the reason I don't want to fall over haha.
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Balor
recumbent guru

Russia
842 Posts

Posted - 02/15/2020 :  03:54:42  Show Profile  Reply with Quote
Landing gear will do nothing for *rollover* protection, obviously.
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ElectricStreamliner
New Member

Australia
68 Posts

Posted - 02/15/2020 :  04:17:19  Show Profile  Reply with Quote
quote:
Originally posted by Balor

Landing gear will do nothing for *rollover* protection, obviously.



Quite right.
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alevand
human power expert

USA
3610 Posts

Posted - 02/15/2020 :  07:33:06  Show Profile  Visit alevand's Homepage  Reply with Quote
One landing gear and you'll have to lean it to that side at a stop, careful not to tip it over, if the slope is to much or the opposite way, it will tip. If you have a landing gear on each side, then it will lift the rear or front tire on a hump, like the one at the end of my driveway, and leave you stranded. Best if its located at the rear wheel, then least likely to lift it, also the landing wheels wont scrub when turning.

C:
Tony Levand
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Tom Schneider
recumbent enthusiast

134 Posts

Posted - 02/15/2020 :  07:48:09  Show Profile  Reply with Quote
Posted - 02/12/2020 : 19:56:23 Show Profile Email Poster Reply with Quote:




"I've been thinking about a front wheel drive delta trike that is as low as possible so the rear wheels can be behind the rider for better aerodynamic.

If I remember correctly it is required that the center of gravity must be below half the track of the vehicle to prevent roll over. With a trike the effective track is within the triangle formed by the front and rear wheels measured at the centre of gravity.

If my centre of gravity is below half of 25cm which is 12.5cm I won't roll over. I can't get that low so my track must increase. Makes sense right?

How would I fix this to prevent roll over without sacrificing aerodynamics?"

Worst case is sliding with the with the line between the 2 leading wheels ( delta front wheel and leading rear wheel) perpendicular to the sliding or force direction.
The perpendicular line between the CG and the line between the leading wheels must be longer than the CG height to prevent roll over.
(Applies to tadpoles and their leading front wheel also).

Edited by - Tom Schneider on 02/15/2020 07:51:43
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alevand
human power expert

USA
3610 Posts

Posted - 02/15/2020 :  14:04:04  Show Profile  Visit alevand's Homepage  Reply with Quote
Yes, you can assume the coefficient of friction to be 1 on dry asphalt, then at a 1g turn there would be zero weight on the inner tire with the half width height formula. It will still flip over if you skid sideways into something. A 12.5 cm cg in unrealistic, that's only 5 inches off the ground. Need bare minimum 3 inches road ground clearance, so laying flat and Cg would be higher than that. Seems the leaning trike is best bet for putting wheels behind the rider.

C:
Tony Levand

Edited by - alevand on 02/15/2020 14:05:48
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Runxner
recumbent enthusiast

USA
456 Posts

Posted - 02/15/2020 :  14:55:45  Show Profile  Reply with Quote
adventuresofgreg.com built an interesting hanging leansteerfwd. How much steering angle do you need? If I remember right he didn't like the handling on off camber and bumps though.
http://adventuresofgreg.com/blog/2005/05/27/exciting-news-the-rocket-is-back-from-body-finishing/

Team Low-Life
Lowracer Test Pilot/Evangelist
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purplepeopledesign
recumbent guru

Canada
705 Posts

Posted - 02/15/2020 :  21:45:42  Show Profile  Reply with Quote
Here you go...

:)ensen







Those who claim to be making history are often the same ones repeating it.

Video of my trike
http://www.youtube.com/watch?v=MdSLRD_2vzc
Photos of my trike
http://www.flickr.com/photos/purplepeople/
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