New forum member says 'hi'

[Thaddeus]

Hey, How's it going,

Thought I'd drop you all a line and introduce myself, you have a nice forum here and it so happens I'm in the process of building a recumbent tricycle with electric assist. I plan on using it to commute to work a couple of days a week. I will have a "few" questions since I've been pretty much making it up as I go along...

In the meatime, I thought I'd post a picture of the work in progress... I did most of the welding today.

cheers

Thaddeus

[/img]

 

[xyster]

Hi Thaddeus. If all else fails, it looks like you've already got yourself a recumbent unicycle.

 

[Thaddeus]

Hey, it's not done yet! 8)

In unicycle mode, it would kinda hurt I 'spect...

 

[RatoN]

Hey T,

are you a welder by trade?

 

[Toorbough ULL-Zeveigh]

I take it you too have a pile of junk bikes to invent with.
Was there an existing tryke that served as your inspiration?
I'm always impressed by anyone brave enough to make it up as they go along.
Looks pretty sweet so far & want to thank you for inviting us along at the beginning of your journey.

umm... you probably get axed this all the time, but it will bug me forever if I don't find out.
Do you happen to own an <A HREF="http://www.thaddeus.com/index.html">HP 200lx</A>?

 

[fechter]

So far, so good. It looks sort of like that thing Knoxie was riding around in the snow with. It looks a fun thing to ride.
With a motor, it will be like a go kart, only legal to ride on the street.

Welcome aboard

 

[Geebee]

Welcome.
Nice start, what kind of front wheels are you going to use, any close ups of the king pin assy's?
fechter, nice description of a recumbent trike.
That will make 3 of us here with recumbent trikes, the rest of the Luddites will catch on to their benefits eventually.

 

[Thaddeus]

Hey T,

are you a welder by trade?

Nope. I'm not a very good welder. "My grinder is my friend." I'm an all around handy guy though and the quality of the welding is getting better.

 

[Thaddeus]

I take it you too have a pile of junk bikes to invent with.
Was there an existing tryke that served as your inspiration?
I'm always impressed by anyone brave enough to make it up as they go along.
Looks pretty sweet so far & want to thank you for inviting us along at the beginning of your journey.

umm... you probably get axed this all the time, but it will bug me forever if I don't find out.
Do you happen to own an <A HREF="http://www.thaddeus.com/index.html">HP 200lx</A>?

Actually I'm fresh out of junk bikes, now. I wish I had some more!

I saw pictures of some tadpole-config tikes and thought it would be a great idea, and thought that boosting it would be better. I am pretty much making it up as I go, though, no formal plans.

BTW I don't have any relation to that web site and don't own any HP products at all. Their printer drivers make my Mac act funny.

8)

 

[Malcolm]

Hi Thaddeus,

My grinder is my friend

Nice bit of grinding so far! Is that aluminium tube you're using or just very clean steel? I'd like to see some close-ups of the steering knuckles as well...

Here's one I made last year for my kids (and me). It only gets used on bike trails and on our quiet street at the moment 'cos it's got no front brakes. Does brilliant 180 skid turns though!
Would be nice to get some proper disc brake wheels made up ... then a hub motor and some lipos...

 

[Thaddeus]

That's a beautiful trike, Malcolm.

Mine is using mild steel, sourced at a local home improvement store, except for the obviously-salvaged (painted) bits.

 

[xyster]

That will make 3 of us here with recumbent trikes, the rest of the Luddites will catch on to their benefits eventually.

I'm fully into giving a 'bent bike a permanent place beside my upright, but they're a fair bit more expensive to buy, and I don't yet have the welding equipment to build one.

 

[Thaddeus]

The pace of building has slowed since last weekend... I am having trouble sourcing some parts. I need bearings and races for the front wheel, still waiting on a freewheel gearset from ebay, lots of piddling details... the motor came in the mail, it was 1/2 an inch too big in diameter to install where I planned, the new location will require me to weld bolt lugs onto the frame...

It's hell being an inventor.

Still, I'm hoping to have the driveline done this weekend, as well as having the wheels on. That will just leave steering, seat, and battery placement/wiring. Progress is being made...

 

[Thaddeus]

Hi,

I got the steering geometry dialed in. I have to fabricate better 'tabs' off of the trailing links, these ones were just a 10 minute hack so I could get it working and check measurements on how everything works together.

The camber, caster, kingpin inclination, toe-in, and Ackerman compensation are all adjustable. When at full lock, the outside wheel describes a wider arc than the inside wheel (this is what the Ackerman compensation is for), reducing the possibility of scrub. Additionally, at full lock, the outside wheel jacks up and the inside wheel jacks down. There is no binding in the mechanism (that took substantial messing around). I have the toe-in set so that it tends to center-steer (I had to chase it down the alley several times to prove this. When it hits a bump, the steering straightens out).

The front crank freewheels without moving the pedals when fed chain from behind. This is so that when the motor is engaged, the pedals will not spin, just the loop of chain. The motor will be installed in front of the metal plate and have a freewheel gearset on it, so that when I'm pedaling, I do not have to spin the motor. A second chain loop will run to the rear wheel, and I should be able to shift gears while motoring or pedalling.

Progress...[/img]

 

[numberonekiwi]

keep up the good work looks like an interesting project and good luck I had an idea when seeing your design and that is to build a plastic cocoon around it so that in rain / snow you can stay relatively dry probably add to much wind resistance thou

 

[Geebee]

Don't over do the toe in, it will kill performance, most manufacturers recomend 2~3mm the closer to zero the better the performance, always measure toe in with someone of similar weight in the seat if possible.
The centering will happen automatically with very little experience.

 

[Reid Welch]

Kudos for you, Malcolm; your bent is inspiring too.
Glad to learn by GeeBee the SwiftnSleek, and you, and Thaddeus.

Question to the benters about Camber.

These front ends are somewhat near identical to Henry's Model T's.
Henry, however, applied an amount of positive camber positively bow-legging the T: 3 degrees tilt outward from the tall tire.
This number never changed through the 21 years of production...correction: he reduced the camber by 1.5 degrees when, in 1924 the low pressure balloon tire was adopted.

I learned from my own Ford, a '22 coupe, that Henry had it about right. The positive camber eased steering effort.
Toe-out was required to prevent "darting" and tread wear.

I can't tell from these pictures, but it almost looks like Malcom's beauty features negative camber (great for stability, needs that mere amount of toe-in; and Thad's bent almost looks like it has positive camber. In which case, the wheels will need toe-out.

Spindle inclination creates the restoring force, but is "activated" by weight; hence, the toe should be set with the rider's weight in mind.

Neutral toe in a cambered front end is an exciting proposition.
I found that the T without toe-in would become quite the road-wanderer. The old timers called it darting.
The fact that the T was so light and had such quick-ratio directly geared steering---made the term "darting" particularly apt.

"Wabble" was another term the old timers knew well.

Do bents ever get into a shimmy? Light wheels probably prevent that. Old cars had heavy (70 lb.) front wheels;
and if they were Model Ts, could and did set up a fierce,
self-sustaining wobble. This, I guess, can't much happen
to a bent. If it did, riding a mechanical bull would seem tame by comparison.

---just my relatively wabbley thoughts...today I drive a Scion xB. I cambered the rear wheels 3 degrees negative.
The handling benefits when cornering are astounding.
Compensating toe-out was included.
Most car geeks do the camber trick for style--it looks sick.
I did it for the handling, as do you guys do too.
But which way?
Henry cambered positive to put the tire patch under the spindle for much lighter steering effort. I learned that spindle inclination need not be very much at all--not for a T;
almost, the less the better---just so long as it never gets knocked negative
(The T had no bumpers).

 

[Geebee]

All trikes are meant to run toe in or neutral (as Reid said it does make the steering lively) the slightest hint of toe out results in the darting behaviour at speed.
Vertical wheels or zero camber is the lowest resistance overall, cambered out at the bottom will allow the trike when cornering to ride on the tread center line allowing maximum cornering grip but means a slight increase in drag as they ride off the center when going straight.
The trikes nowdays usually run inclined king pins so that the tyre contact patch is inline with a line drawn through the king pin pivot as this helps reduce or eliminate brake steer, the earlier trikes if you only braked on one front wheel would swing toward it.
Rear wheel brakes on tadpoles are usually considered as park brakes only (except the KMX as it is meant for stunting) as they have a nasty habit of causing the trike to swing the rear around and roll as the rear is lightly loaded.
I have not experienced any wobble up to 90 kph.
If you want I can probally hunt up a link on trike design?

 

[Malcolm]

You've got sharp eyes Reid!

Geebee just about covered everything there. My trike was intended to have zero camber, but due to a slight oversight in the design department it actually has negative camber – the wheels lean in at the top. Seems nice and stable in a straight line, but scrubs slightly in corners.

Not sure about the Model T, but if the king pins were close to vertical then leaning the wheels outwards at the top would bring the tyre contact surface closer in line with the king pins, making steering lighter.