Another FWD Delta trike.

Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
Today saw some "bits" being assembled (not necessarily in the right order, or very well....Of course). ;)

I made one of these with 2 8.8 grade M12 bolts. They are aligned and anchored with internal plates that are welded to the head of the bolts and puddle-welded into the main tube to ensure they are captive and cannot "waggle-around" or be pulled out. On the ends of the tube are external 3mm plates (also with 12mm holes) which are welded to the main tube.





If there was one lesson drummed into me by John Price (Sandman) it was the value of clamping and "jigging" to ensure the best possible "fit" and "alignment".
Here are more of the "parts" all set out and clamped into position.



When all the welding operations were over I was left with this:


It has not come out too badly. There is a 2mm divergence between the swing-arms separation "front-to-rear" over their 300mm length. At the axle ends they are 318mm apart. and at the other end 320mm.
I think it is unavoidable to have some weld-shrinkage distortion so I will have to live with it. Effectively this will appear as a slight Toe-in of any wheels that might get attached to the swing arms in the future.

Just a bit of retirement fun really.
 
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
The bit I am puzzling over is the FWD. Yes, I know what it ought to look like, but "me" with a 29" inseam straddling a 24" wheel places me almost on top of the headset. :eek:
NO, I don't like the flow-roller. 🤢
FWD/MBB as per Cruz-bike seems to always want to spin round and either smack you in the goolies, or attack your shins.:mad:
So I need to do something else. :p
 
Joined
Oct 19, 2012
Messages
1,016
Location
Wakefield, UK
How about platform shoes?:p

Other than the shoes option. Narrow would dictate not being inside the rear wheels, meaning either fore of them or above. Above really means the rear two must lean to keep any stability. Fore of them could start to get very long unless you put the BB more above the front wheel rather than just in-front. Something like this:-


I appreciate that one is a 20" wheeler but can't see why it wouldn't scale up, or go tadpole with a semi-recumbent something like this but with a set of wishbones like the ones in the below video it and balanced like any regular bike. This would be extra plush as such a wishbone set is a natural shock absorber itself even without a suspension unit.



 
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
It has been a while. Life and family stuff has been very much in the way.
Today I welded some mounting tabs onto the swing-arms.
I had some issues with weld porosity, but there is enough solid weld there to hold an elephant I think.
The SA hub backplates fit quite nicely and a picture will be added as soon as postimage's network/server issue is resolved.
Done:
 
Last edited:
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
I have been "busy" decorating my house for the installation of some new windows, so no appreciable work has occurred on the bike front.

Today I found some time (after knocking another item off the "Honey-do" list) to have a play at trike stuff.

If you are aware of the access problem I have then you will immediately understand the reason for the funny looking contraption shown below.

This location is the "pinch-point" between my front yard and the back garden and the trike storage sheds.
A "Normal" track trike cannot be brought down the side of the house.; and a narrow track delta-trike is likely to be a little unstable.
This is my attempt to overcome that particular problem. This will certainly fit down the side of the house, the "balance-scales" linkage will attempt to provide an ability to allow the trike to tilt "gracefully" in any corners.
When both rear wheels are braked all tilting action is frozen by virtue of the need for wheel rotation to occur in order for the trailing arm to move so at a standstill the trike should NOT fall over.

Clearly such an arrangement of the rear wheels mandates that the trike is FWD. What form this will take is yet to be determined. I have looked a twisted chain but it appears very problematic to avoid chain derailment.
I am not saying it cannot be done, clearly it can and IS done; but I think it is difficult to get right.
Other options are MBB or flow-roller styles of FWD.
Thinking cap on.




 
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
A little bit more work on it today.
I decided to see if some of my previous "works" could be used to pull this together. I think they can.
Here are the swingarms on their cross-beam and stub-axles clamped to an earlier main-frame that I made.



Hard to see from a frontal view (with those crates in the way holding the frame up).


It might just work! I think I can see a way to do this. :D
 
Last edited:
Joined
Feb 7, 2008
Messages
2,681
Location
Nottinghamshire England
Green balls , should be a talking point in the shower .....

No wonder you have problems with pedal clearance ?

I'll get my coat....
 
Joined
Feb 7, 2008
Messages
2,681
Location
Nottinghamshire England
The purple bit is at the wrong end too!
Hmmm ????

Maybe it is RWS ?

We may as well have the maximum number of crash creating elements in one design as we can get ?
 
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
Ooohh..... so much negativity. :eek:
I am just trying to re-use stuff I have already made before and have a bash at a non-Python delta; that's all. ;)
When it is a great success you will all want a ride on it. :p
 
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
Update 14th Oct:
One of our steamed esteemed members (you know who you are, but don't tell them your name Pike) pointed out to me (not unkindly) that before I sink more time effort etc. into the madness that is a tilting delta trike I should perhaps check that it doesn't just fall over (like the last one kept doing). It is unfortunate that several bits of tube have to be consumed and at least strongly tacked onto a flying formation in order to do any form of testing.
Today I had a bash at attaching the tilting bits to the static bits and I actually sat on the main keel with all of the wheels on the thing, and it felt good.
I could not in the time available (and with the skies darkening and rain beginning to fall) have an opportunity to do much "testing" as such.
In fact I didn't even have brake cables on it, just some less than tight zip-ties on the brake actuating arms. The trike was able to stand up all on its own and resist falling over with a "gentle" amount of lean.
Here are a few pictures. The links that actuate the tilting are not adjusted to get the swing-arms in line with each-other so it does look a little "odd".




For those of you that can stomach such a thing, here is a tiny video of it.

 
Joined
Feb 7, 2008
Messages
2,681
Location
Nottinghamshire England
Onward and ever sideways I say ....
 
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
Onward and ever sideways I say ....
When you ride it you will be smiling with a big broad grin............. right up until it folds up under you and knocks all your teeth out. ;)
 
Joined
Feb 7, 2008
Messages
2,681
Location
Nottinghamshire England
When you ride it you will be smiling with a big broad grin............. right up until it folds up under you and knocks all your teeth out. ;)
My own knee's will knock my teeth out unless you make the seat/pedal length adjustable ;)
 
Joined
Oct 19, 2012
Messages
1,016
Location
Wakefield, UK
With the weight of a rider on there'll be a much stronger force trying to pull it over at standstill. I can see the tyres need to roll, though not very far, to lean but will a riders weight be enough to simply drag a tyre enough to lean? Once any lean starts the force will rise exponentially dragging the tyre further quicker. If it does lean with a rider on then a sideways disc brake on the top link axle would certainly prevent lean.
 
Joined
Feb 20, 2013
Messages
781
Location
Axedale, Victoria, Australia
Website
axerail.coffeecup.com
Danny: It looks very interesting. Many times in history there have been things that attracted the "That won't work" comments but turned into something with a combination of Patience, Perseverence, Dogged Determination. Time, and Money - in varying amounts. Keep it up and something will emerge at the end of it.

You may even create a leaning to that sort of thing.
 
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
Last night I investigated the disparity between the angles of the trailing swing-arms (relative to the horizontal plane).
The fact that the attachment point of the tie-rods is 2" from the swing-arm axle and the hub of each wheel is 12" from the same axle means that tiny changes at the one end mean substantially magnified changes at the other end. The tied-rods are 12mm stainless steel with LH & RH threaded rose-joints. Properly adjusted the arms are all now level to within <1-degree. ;)

I agree about the "progressive collapse" once past the natural tipping point. I shall purchase another pair of SA locking brake levers and put proper cables on. Another consideration is that these drums/shoes have never been used and will need bedding in to be properly effective.

We shall see. :)
 
Joined
Oct 19, 2012
Messages
1,016
Location
Wakefield, UK
Another thought on the brakes stopping the lean is getting under way again. If it's leaned even slightly to one side when stopped you'll be at a slight angle the instant you get going unless you intend to put a foot down at each stop which itself is not unreasonable. This may be no problem at all and one that you adjust to and learn just as with a two wheeled recumbent and frankly that is what I would expect however a sideways disc on the top link pivot would allow you to lock it at will for going very slowly where it will then behave as a std delta and can be unlocked as soon as you feel you're fast enough to balance. It could be viewed as like having training wheels. One big disadvantage would be you would need either an extra brake lever or friction shifter and juggling regular braking with tilt locking would be a skill that would also have a learning curve or you'd be down to just one normal brake lever and one tilt-lock lever though the one normal brake lever could operate two brakes which would probably be the better option.

Here's one not dissimilar to your mock-up though with the link under the arms rather than above. There's a sideways disc at the link bar pivot. The rider seems to get under way very well on immediate release of the brake levers.


The rider here is somewhat lower and this may help with eliminating any flopping tendency.
 
Last edited:
Joined
May 31, 2013
Messages
2,844
Location
South Benfleet, Essex, England, UK
Update 19th October 2020:

Some new bits arrived from SJS Cycles this morning. :)
2 QR axles and 2 Sturmey Archer Brake levers (esp. for drum brakes and with parking brake buttons).
I put the wheels on the trike and the levers & cables on a spare handlebar. I adjusted things so that the parking brakes came on and the trike was able to stand upright on its own.
I then sat on the bike and pulled the brakes on hard and tried to push the bike over from side to side.
My experience was that the resistance against toppling was high and the tyre had to loose traction with the ground for the swing arms to move.
This is very logical because you are in fact unloading one wheel while increasing the load on the other.
So the answer to the "staying upright at a stop" question seems to be YES?
I need to put a seat on there now and work out how much I need to lengthen the main keel by and provide a permanent home for a BB shell.
Where you see the BB shell right now it does incur interference with the wheel if the wheel is turned significantly in either direction.



 
Last edited:
Top