Delta trike design - constraints and solutions ?

I've bent male M10 rod ends in similar positions. They bent alarmingly easily too. I always try to work things to have female rod ends where I can. For the probable upcoming 4ws quad I've located some extra strong M12 units as I had to use male ones.
 
Threaded rods are ment to bend. The thread is just a wrapped around bending line. A M10 rod is maybe as stiff as an 7mm solid rod.
 
I've bent male M10 rod ends in similar positions. They bent alarmingly easily too. I always try to work things to have female rod ends where I can. For the probable upcoming 4ws quad I've located some extra strong M12 units as I had to use male ones.
+ Maddox

Yes I was going to use M12 anyway and do have the female versions , however they have not bent yet in the Python and the forces in the middle are incredible how did you manage to bend some ?

Paul;
 
Probably through being fat if I'm being honest. They were on the mk1 tilter at the wheels similar to being used as a kingpin pivot. I used high grade m12 male on the mk3 and they're fine.
 
I didn't bend those rods in bike applications. But Robot Wars has its own hazards.
Using threaded rods as structural elements is contra-indicated.
 
So having been to see pedal car racing I needed to try a ladder frame mock-up ?
space-frame-sides-sm.jpg


Current inspiration is this , a car from the Royce team
So outside

ped6-red.jpg


and inside - so I like the steering and the drive shaft arrangement. These cars are approx 48" w/b and lower than i want to be [ I think ] so plenty of ' figuring ' needed :)

DSCF6670-sm.jpg


I stripped the front and rear axles off the main boom mock-up and made the main boom free standing [ probably can't take my weight though ]
I then made a ladder frame the front is dropped 45' and is 5" from floor to allow it to be as short as possible and still clear my pedals , also turns out it is no longer than o/a length of main boom mock-up a big +.
DSCF6675-sm.jpg

Seems I actually have 3" of pedal clearance so room to manoeuvre ? the dropped part could be 2" higher ? or the ladder frame could be 2" lower etc etc.
Looks like a tube up to the BB would be almost vertical [ unexpected ]

DSCF6685-sm.jpg


transferred all the important points from the main boom to the ladder front axle , rear axle , seat front mount and seat rear mount.
made a couple of cross pieces up to maintain shape whilst tinkering and tried previous jackshaft cross piece to see where it might go ?
a second tube from the BB would go to this.

Lots more thinking and wood needed then which to build ?

Paul
 
Last edited:
Wow did I only start this about Friday ?
Previous design
DSCF6588-sm.jpg

new design
DSCF6687-sm.jpg

I think this looks better [ more polished ] as I am happier copying an existing design than staring at a blank sheet of paper ;)
My previous still had lots of area's needing solutions i.e main frame - BB - seat mount etc etc

So couple bodges to get it out into the sun [ to be addressed later ]
  1. no kingpins [ yet ] so simple M12 threaded rod front axle
  2. BB rough position height not resolved yet
  3. seat does not have a rear mount yet
  4. rear wheels simply bolted straight through frame[ may do that in steel one ]
  5. no steering provision yet
Dims are
track front 30.5" would be better 28" - 30"
track rear 26" may massage to give me 28"
w/b is 35" spot on
length 56"
seat front 11" from ground - not bad
BB 18.5" - to high for seat height however it can only lower till my heals hit front dropped X member
front X member from ground 5.5" - should be a little higher I think
outer frame members 18" apart
x member forward of seat 7" from seat - for jackshaft

DSCF6689-sm.jpg


front X member compromise attempt to shorten front , still have ground and heal clearance [ it may work ]

DSCF6701-sm.jpg


added a piece of wood for BB to jackshaft X member to mount this you stand in the gap between the wheels and place foot/feet over side rail and into gaps either side of rear BB tube.

DSCF6702-sm.jpg


still no idea if I can actually get some steering control rods into design without either fouling pedals or making it longer , need kingpins before I look at that can of worms labelled Extra Large !

Paul
 
One of the drawbacks with the twin spar perimeter frame is each wheel is now free to act on the rail it is attached to to try to twist it. With a single spar that twisting force is stopped by the other wheel mounted to the other side of the central rail. It's all but impossible to brace as your feet need that space. The further towards the axle you can get that front crossmember the more it will help resist that force.

Do you have enough room between the wheel and those rails for the wheel to turn enough? It doesn't look enough but could be camera angle trickery.
 
One of the drawbacks with the twin spar perimeter frame is each wheel is now free to act on the rail it is attached to to try to twist it. With a single spar that twisting force is stopped by the other wheel mounted to the other side of the central rail. It's all but impossible to brace as your feet need that space. The further towards the axle you can get that front crossmember the more it will help resist that force.

yes a worry , that space looks huge ! it is approx 24.5" long and about 8.5" to BB spar.
I can move the jackshaft X member forward at the expense of making it more difficult to step into it.
I can move the front X member further back by raising the BB and if needed the seat.
I could add a small X member in the same position as in the pervious version ?

Do you have enough room between the wheel and those rails for the wheel to turn enough? It doesn't look enough but could be camera angle trickery.
That is a ' I hope so situation ' ;)
To make the most of the space [ about 5" ] I think I need the kingpin as close to the wheel hub as possible ?

Paul
 
If you only have 5" between chassis and wheel you're getting a best of 30 degrees of steering. In reality probably less. You'll need 7" for 45 degrees and 8" for 53 degrees as minimums. Keeping the kingpin close will maximise it.
 
So more musings ?

DSCF6703-sm-data.jpg


I inserted the front X member from the mono boom frame under the ladder frame , now the 13" is the width needed to clear my shoes and this position is the distance from the BB to get heal clearance however the ladder frame is 18" apart ? why ? not a clue !!!

So next up is to make 3 more X members only 13" apart and not 18" and re-assemble that should give me approx 6.5" for the wheel to turn also the horizontal piece could actually be added under the rails of the ladder frame if needed for more stiffness ?

Then really need some pedals adding to see what the BB height maybe ?

Paul
 
So chickened out and made the new X members 14" apart , well apart from the one I accidentally cut @ 13" :(

DSCF6711-sm.jpg


Front wheels still a little to wide @ approx 31.5" track , will fix soon.
Rear track is now currently approx 20" , probably pad that out a little as we go along.

DSCF6713-sm.jpg


Wheels still through middle of frame side rails so frame is approx 9" from floor , seat front 12" and BB 18.5" [ much to high for current seat height ]

DSCF6714-sm.jpg


Now 5" between frame and wheel , plus realised wheel rotates about contact patch [ if king pin inclination angle correct ] so maybe a bit more ?

Need to sort BB out next as either:-
it needs to be lower = pedal clearance with dropped X member
or
seat needs to be higher
or more likely both to achieve BB about 2" above seat front height
I started this thread 19th December , if I had stuck to plan A a delta it would probably have been built by now ?

Paul
 
It would also have been less effort to use a basic CAD program.

? Only if that is the way your brain works AND you knew how to use the CAD program in the first place.

and of course I have built 3 mock-ups so far .....

My brain likes to see stuff in the flesh and I can compare the mock-up to the existing Python.

Paul
 
Last edited:
Well I have found 5" !!!

DSCF6689-sm.jpg


Current pedals added , yes both same length this time @ 170mm have 5" of clearance to dropped X member so what to do with that ?

So it's all about BB/seat height difference , I want about 2"

I think first thing is to raise X member by 1" as currently only 5.5" from ground
Seat will really be 2" higher as there is no mounting hardware in picture

Next lower BB till I have achieved 2" height difference with seat and take another look...

Scope of course to go to 155/150mm cranks if necessary , trying current Python with 150mm

happy Easter all who partake in this sanctioned chocolate eating binge ;););)

Paul
 
Hello, Paul!
I saw your topic some days ago, but at first didn't pay too much attention, thinking that it is only about your beloved tadpole (ultra-light, ultra-short, ultra-C.G near front-wheels). Such vehicles are very popular among Zombies? However, for the second reading I understand that there could be a lot of wisdom for other types of HP Vehicles: information, suggestions, dilemmas, facts and dimensions of mechanic! So, I was reading it for the third time, copied a lot of photos with details, sketches with measures too, add some more form text and translated to metric system! Therefore, no need for you to go to your workshop/garage to check all that for me.
Now, I could make my own sketches for my position on my vehicle, with measures for pedal-system and steering, transmission, too... Of course, everything should be checked on components that I already have and compared all that with my big body - and feet: shoes are 46 ~ 11 in the UK? Or 29.5 cm, almost one foot?
It was interesting to follow your way of thinking and making dimensions about layout in general and the main details! You started with simple recumbent tadpole three-wheeler and finished with four-wheel quad in two variants of chassis-frame: central back-bone and two parallel side girders. Then there were two meanders in thinking process (model-up construction, too): rear-wheel steering (not for me to experiment this time) and two bicycles connected in a parallel way (as my old quadricycle)…

I shouldn't use so short wheel-base as was your goal and results, because:

  • I would never use my vehicle on bicycles paths/lines with obstacles, because our paths/lines do not have them;
  • I would not transport it in our small car Citroen C-1, it is too small even for kids-kart and I do not have a need for that (wouldn't transport it to excursions, shows and races);
  • I could not have C.G. over (or very near to) my 26" rear-wheels, because of their fragile construction;
Probably that wheel-base should be around 152 cm ~ 5 foot or 60", with no more weight at rear axle than 60% of total weight...
So, I was not only stealing your knowledge and experience, but space on this topic, too!

My very best regards,
P.S.: What's happened with your project: finished as 1:1. wooden model (witch variant) or even in steel frame?
 
Hey don't I ramble on and on !

It was mothballed for maybe 7-9 months because I was given a real pedal car :
Pedal car refurbish [ another cul-de-sac I went down ]
However that has now been passed on to a scout team to try and race as the more areas I looked at the more problems I found and in the end it simply worn me down.

So wooden quad is back on work table and being though at ! looking currently at kingpins [ Italian Style ] and rear wheel drive.

With your lack of welding access I would seriously ask Mott & Motofoker builders if either of there machines could be built without welding ?

They can both be redesigned for the features you want ?

Paul
 
Click for DIY Plans!
Back
Top