Thoughts questions and ideas

paul fellows

Active Member
Location
Middlesbrough UK
Thoughts questions and ideas for the builders of HPVs

Any pictures of a front wheel drive recumbent. What are the pros and cons.

As any built or seen an inverse recumbent. With the rider in a sort of ski jump position, head first [low drag] with the legs free to push down and back [max power].

Ultra light construction ultra simple.
This is a plee that anyone who is about to start a construction project should have a look at the sculptures of K Snelson and the idea of floating compression structure that they are based upon. 3 rods that only have to be strong in compression and 9 cords to handle the tension. With pretension will make a frame that will be stronger and stiffer than a normal bike frame.

http://kennethsnelson.net/tensegrity/
 

Scoosh

Velocouchiste
Moderator
Location
Edinburgh
Front wheel drive: Raptobikes

'Inverted position': Graeme Obree's world record attempt

Do a search in this Section and see what comes up :thumbsup:
 

stuee147

Senior Member
Location
north ayrshire
i have looked at FWD systems and as far as i can see they are a lot more trouble than they are worth.
firstly you have to consider you normily stear with the front which would mean your looking at a complex universal joint system to maintain drive while stearing.
the other way to go would be have FWD with rear wheel stearing this can work and can result in a nice tight turning circle but it can take some getting used to. if you have ever driven a forklift you will know what i mean.
the other issue with FWD if your taking about trikes is that you really need to split the drive in some way. which can cause issues with over complex chain drives or differential systems. having said that i have seen a few done with the diffs and drive shafts from electric wheelchairs and that seems to be the best way. if you have the money to spend as they arnt that cheap or easy to find.
another thing that has always concerned me with FWD is weight distribution between front and rear wheels. iv only really delt with trikes where most of your braking is done with the front and drive with the rear so the weight if i remember rightly 70/30 bias to the rear to give traction and with the weight more to the rear as you brake hard the inursher pushes your weight forward, but because the weight distribution is more to the rear it helps prevent tipping forward. where as if you have a FWD system you will need to have your weight distribution more to the front to help keep traction espeshely on hill climbs. but then it would mean you have a very good chance of tipping forward under hard braking.

at least thats how i see it lol

i hope thats help a bit

stuee
 

stuee147

Senior Member
Location
north ayrshire
oh i know it is all possible its more a personal opinion that FWD is more trouble than its worth, having said that it is something i have thought about and would like to try. as if you can get it all working just right it could be great. and to be honest the chalenges that making it would give is the main reason i would like at some point to try to build a FWD.
i mean if its not a challenge then whats the point of doing it ^_^

also althow i think it can look over complex and a bit ugly i think thats half the appeal
 
OP
paul fellows

paul fellows

Active Member
Location
Middlesbrough UK
i have just been looking at the thread on waky recumbents. i saw 2 fwd that where identified as Atomic Zombies. they looked like a nice simple way to do fwd

there seems to be some concern about how heavey bents are, yet a look at some pictures of them sugests that they are over enginered to compensate for the lack of triangels that df has.
if you look at a floating compression frame then the rods need only be strong enough not to collapse when squeased lenthways, perhaps a stiff plastic pipe might do?
 
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starhawk

Senior Member
Location
Bandhagen Sweden
The guy who sell the Horizontal bike have the ad "move lika a Cheetah" but we are not cheetahs and it's not normal for us to move on all fours. Riding with the head at the front doesn't seem to be a very safe proposition. And what about vision? you either get a very soar neck or have to buy those glasses he has developed that enable you to look forward when you are facing the ground. I rather have my feet forward and a sitting position which gives my a wide view forwards
 
OP
paul fellows

paul fellows

Active Member
Location
Middlesbrough UK
ok how about a tadpole that leans in to corners like a bike???

markg0vbr said somewhere that it was possible if your rich but gave no clue as to how
 
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OP
paul fellows

paul fellows

Active Member
Location
Middlesbrough UK
nice bike!
Iv moved on and am now thinking about a tilting trike, with its seat at chair hight.

Although the steering and the tilting will have to operate through the two front wheels, they will need to have separate mechanisms. It will need to be able lean in to sweeping turns at high speed, but stay upright when turning round tight corners slowly.
 

classic33

Legendary Member
There are several FWD trikes on Atomic zombie the most interesting one is probably Stormbird's Python trike
This one the original uses a 20" mtb triange and an unusual steering joint .
View attachment 84414

The Python can also be ridden no hands as the trike can be steered by the pedals

the thread is here on AZ along with many more .

http://forum.atomiczombie.com/showthread.php/8210-Building-a-python-trike?highlight=python+trike

regards emma / twinkle on az
Thought I'd come across you elsewhere.
 
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