Electric Reverse Trikes. Ideas, Rants, Collaboration?

Ok, I have been following the hub motor discussion by MarkCycle.
http://endless-sphere.com/forums/viewtopic.php?f=10&t=7718&p=152177&hilit=hub+motor#p152177

And a lot of folks on that topic have expressed an interest in building a trike of some kind, some standard trike (1 wheel in front, 2 in back) and some reverse trike (vice versa)

I have built a few (can be seen at tshtrikes.com ) and would like to build a lightweight 2 seater, fully faired and use MarkCycles 10k HubMotor

I would also like to use the front suspension and braking from a 660 raptor atv

Advice on this? the raptor is about 450lb empty, and is designed to be beat up out in the dirt so durability in a 650lb road going machine, shouldent be an issue. The brakes do look awfully little to me though...

Very nice website! I too am wanting to build a 2 seat electric reverse trike. I really like your diesel electric hybrid, that is very similar to the design I have been working out thus far. My goal was to build an aluminum space frame and cover it like Robert Riley does. However, I found this website : http://autospeed.com.au/cms/title_Building-an-Ultra-LightWeight-Car-Part-1/A_110989/article.html . While the material is rather exotic, the idea is interesting and would likely allow Mark's motor to be used. I've used carbon reinforced aluminum honeycomb at work and it is breathtakingly strong. I'm not certain that I'm going to go this route yet, but it does add one more option.

Since I still have not given up on my aluminum space frame design. Does any one know of a good website that details tube diameter selection based on vehicle weight, or any tutorials for custom building a space frame?

-Jim

It just occurred to me that I could potentially build 2 or 3 trikes in the shop (at, like cost) if a few of us were to collaborate on a design, its been a real godsend for "three thumbs" me to be able to draw out his crazy designs and have my fabricator just build them

Also I wanted to include for consideration one of those ac motors that thunderstruck is selling. (food for thought)

todayican2 said:

Ok, I have been following the hub motor discussion by MarkCycle.
viewtopic.php?f=10&t=7718&p=152177&hilit=hub+motor#p152177

I have built a few (can be seen at tshtrikes.com ) and would like to build a lightweight 2 seater, fully faired and use MarkCycles 10k HubMotor

I would also like to use the front suspension and braking from a 660 raptor atv

Advice on this? the raptor is about 450lb empty, and is designed to be beat up out in the dirt so durability in a 650lb road going machine, shouldent be an issue. The brakes do look awfully little to me though...

Click to expand...

Wow, I've been following your builds and didn't know it was you.

I hadn't seen your use of the Raptor front end until now. Its very interesting and instructive to see.

First, ATVs have plenty of swept area on their discs, but they are skinny non-vented discs because ATVs don't use them much. They are about the same area as a motorcycle rear brake. They travel at low speed, don't really coast and a lot of braking energy is dissipated in the rear and by the driveline. My opinion is they are fine for very limited road use, like a lightweight trike, but I their ability to dissipate heat is marginal. I wouldn't want to ride them down a long grade on an efficient machine that rolls easily. They will overheat for sure doing that. The drum brake spindles may actually be more suitable to our application, but they weigh more. Your vehicles are going to come in on the heavy side, being mostly steel.

Second, I think these spindles are perfect for applications in the same weight class as the donor ATV. The A-arms, however, seem to be less than ideal. Look at the geometry. In the Raptor, they are installed at a static angle to the ground of what- 10 to 15 degrees? That provides a lot of travel for off-road use, but it puts too much deflection into the ball joints at road ride height (almost level arms) and seems to have an adverse camber change through the suspension travel. You can see it in the pictures on your website. As the suspension compresses, the top of the wheel should tip in toward the chassis, tipping the contact patch of the tire out, so that the tire stays flat on the ground as the vehicle leans. I'm not sure how your suspension is behaving, but it is related to the fact you are using about the top 1/3 of the travel designed into the system. ATVs are much less sensitive to these changes than road vehicles.

You also need to lengthen the steering rack center section to match the extra track built into your frame, or you're going to have real problems with bump steer. The tie rods will push and pull on the wheels as they travel, creating unwanted steering inputs, if the tie rod joints at the rack aren't in the same plane as the A-Arm pick-ups. As it is, I think this front end would be squirrelly on the road until those issues are sorted out, and I'm not sure they are solvable using the Raptor arms. I was going to use custom, narrower arms for just that reason. You obviously have the skills necessary to fab some up, and you've had to modify a-arms already.

I'm interested that you are using the Raptor R&P steering box. That's great, if it were just a little wider it would be perfect. I wonder how much it weighs...

You guys are really banging out the vehicles. That's fantastic. I really like your diesel-electric hybrid, and its great to be able to see your progress on all this work. Good Show.

Tom

Thanks for the feedback TomA I have the same concerns about the front end geometry. i was considering going to a lightweight mac strut arrangement with geo hubs and fabbed arms.

I have been thinking along another track as well, and it involves accepting a problem, then capatalizing on it. I may be going on a limb, engineering wise, but it wouldent be the first time lol.

Ok, we all know using a car tire in the rear gives a good contact patch under accelleration, but is at a disadvantage during turns when body roll puts is on its side. I bike tire, less patch for accelleration, but a better "side profile" hmmm

so...

I see a lot of reverse trikes with bike tires, some with a bike tire in just the rear, some with both front and rear. so, assuming 3 bike tires is acceptable from a traction standpoint on a non hot rod (like a 10hp hub motor trike, or even a 25hp ac driven one) what about doing a single arm suspension, better for aero, the rack could be right at the pivot and the camber wouldent matter with the rounder profile of the bike tire?

kingjamez said:

Very nice website! I too am wanting to build a 2 seat electric reverse trike. I really like your diesel electric hybrid, that is very similar to the design I have been working out thus far. My goal was to build an aluminum space frame and cover it like Robert Riley does. However, I found this website : http://autospeed.com.au/cms/title_Build ... ticle.html . While the material is rather exotic, the idea is interesting and would likely allow Mark's motor to be used. I've used carbon reinforced aluminum honeycomb at work and it is breathtakingly strong. I'm not certain that I'm going to go this route yet, but it does add one more option.

Since I still have not given up on my aluminum space frame design. Does any one know of a good website that details tube diameter selection based on vehicle weight, or any tutorials for custom building a space frame?

-Jim

Click to expand...

Hi Jim:

You won't find a lot of aluminum tube space frames, because it isn't an ideal application for that material. Aluminum is usually used in sheet, or better, honeycomb sheet, to make 3 dimensional structures. Aluminum tube doesn't really have the strength to take the point loads in a welded space frame, which is why Cannondale bike frames used such fat tubes. Those alloys are also expensive, hard to TIG weld, and the finished product will be fragile. Bonded honeycomb sheet is a more promising and proven material and technique, but if you're going to do that, you're better off with a composite structure, not a bonded aluminum one. Composite won't peel, corrode or bend, and its more durable and easily repaired than aluminum.

If you're going to learn the techniques of shaping and glassing foam for a body skin anyway, why not go all the way and make most, if not the whole trike out of it? The best books on the techniques, I think, are by Jack Lambie (Composite Construction for Homebuilt Aircraft,) and Martin Hollman (How To Build Composite Aircraft.) Burt Rutan's construction manual for the VariEze and LongEZ is the ideal beginner's guide. You can get them all at Aircraft Spruce and many other places.

I had seen the Trev from the University of South Australia, and its a great achievement. its one of the inspirational benchmark designs for my own work. That folded honeycomb sheet is a winning formula, and its expensive, too! This is the lightest 2-seater I have seen, though, by far. I will probably use some sheet techniques for the floor and suspension interfaces on my vehicle. For my purposes, a thinner, lighter honeycomb than they used will be more suitable.

Tom Alvary
Just a Tinkerer
White Plains, NY

todayican2 said:

Thanks for the feedback TomA I have the same concerns about the front end geometry. i was considering going to a lightweight mac strut arrangement with geo hubs and fabbed arms.

I see a lot of reverse trikes with bike tires, some with a bike tire in just the rear, some with both front and rear. so, assuming 3 bike tires is acceptable from a traction standpoint on a non hot rod (like a 10hp hub motor trike, or even a 25hp ac driven one) what about doing a single arm suspension, better for aero, the rack could be right at the pivot and the camber wouldent matter with the rounder profile of the bike tire?

Click to expand...

The Geo hubs, arms and struts are a good match for your vehicle. Those struts will be tall in front, though. Maybe your air setup adapted to it would have a lower profile.

I also thought about a single arm/strut suspension. If I stay with a full envelope body, it would be great, but all the available (car) components are just too heavy for me. There's also just taking a go cart axle and hinging it in the center. This is most similar to a "four bar split axle" design from hot rods and would work for me, maybe even with only one rod per side. The Ford "twin I-beam" suspension is a variation on this theme, with longer main arms to minimize camber change. That would work on a bigger trike. All these single arm designs do indeed have the correct camber curve in travel, although the shorter the arm, the less ideal the curve.

Its interesting about the tires. Do you really mean bike (bicycle) tires? They scare me and aren't up to my requirements. Motorcycle tires with their rounded profiles probably are better for our purposes than small car tires, and they'll also probably be more efficient, too. I'm using them for the size, mostly.

Tom

Yes, I was referring to motorcycle tires
So, if were looking at throwing camber to the wind and using motorcycle tires, a possible way to go would be a disc brake model t hub (because it pivots on a very small knuckle and is light, and is widely available new from aftermarket suppliers. riding on a single a arm. actually I was thinking a "diamond arm" with a second "a" on the interior of the trike leading to a shock.

Ideas?

A-arms like this were common in Grand Prix and formula cars in the 1970s. Typically, they were the upper arm of a two arm system. Make your diamond arm solid and thicker through the hinge- like a polygon- for strength and aero. Cool, but I still wouldn't do it. Eliminating the parallel arms and going with one arm might not save weight. You'll need strong parts and attachments. Double wishbones spread force around the chassis well, and can be the lightest overall. Mine will be composite and fiendishly light if I can manage it...

I singel arm won't lead to excessive camber change if the spindle is mounted to it with a ball joint, and a strut above instead of an upper arm. That's the metro.
Staying with a single arm and fixing the spindle to it is too much camber change for me. I would probably be better off with a buggy sprung front axle. Not a bad idea, actually, in carbon fiber...

You could also use a thin tranverse leaf spring that spans the frame and mounts both spindles in place of the lower arms, and then your upper "diamond" arms would be smaller, and only actuate dampers and an anti-sway bar. Simple, yet exotic. Clean aero, and devilishly hard to buy just the right spring. I think some golf carts are set up this way. Then there is the remarkable Citroen 2CV longitudinal single arm suspension. That would be sensational if you could use it. Light and strong, too, and spot on to your load requirements. Made for front wheel drive. Can be narrowed easily. Look here: http://members.tripod.com/~costajulio/citroen/2cv.htm

There are many possibilities. You actually need very little suspension travel, as I am sure you have seen from your projects.

Your enemies with designing your own system are weight and bind, but you're on a great track looking at Model T stuff. Those Edwardian era suspensions are strong, simple and generally light. The aftermarket parts are truly light. No way will it handle like a double wishbone front end, though. If your vehicle uses skinny tires, accelerates slowly, corners at very modest g and tops out at 60mph, (e.g. the exact performance envelope of a Model T) then that front end (or rear, really) might be ideal for you. You don't need the ground clearance required in 1905, so you'll probably want a dropped axle, but it all depends on how it fits into your vehicle. Keep in mind, those prewar front ends look deceptively simple, but they have to be set up just right or they bind severely and you won't have any movement in certain modes, like braking, cornering, or braking with the wheels turned. Not cool. Interesting idea, what's old is new...

At the end of the day, I'd probably go with the Metro front end. So much less work than anything else, and a lot more likely to perform well.

Tom

I found this today: www.zwheelz.com the ZW2-C is almost exactly what I've had rolling around in my head.

-Jim

Very cool thing, that ZW2-C.

The bare chassis is 1000lbs. Projected weight with batteries and bodywork is 3400lbs.

All these projects that start with mild steel and car parts wind up being incredibly heavy to my way of thinking. This is a cool trike, but if you started with a Toyota Corolla glider you'd have a much more serviceable, practical and safer vehicle for similar weight and performance, no? I mean, if we are going to purpose build an EV, shouldn't it be an order of magnitude lighter than an easily converted OEM machine? I'm not being critical, everybody should build what they want and we can surely all benefit from seeing that and sharing, but for myself projects like the ZW2-C and the Riley XR3 look like the hard way to save very little energy on the road. (Oh wait, I am being critical about one marketing claim: I just don't believe the RQRiley XR3 claims of "up to 125mpg diesel and 225mpg in diesel-electric mode." That's a totally unsubstantiated commercial sales claim, and I'm saying out loud that its undemonstrated and almost certainly false. No vehicle in that weight class has ever used so little fuel with, literally, garden-variety parts. I'll apologize for calling them liars when I see the performance data. Whatever...

Anyway, I am going the scratchbuilt trike route versus converting a car (forget scratchbuilding a car- it would be practically unregisterable and uninsurable as a hobbyist) to save weight and drag. The ZW2-C doesn't appear to do enough of either to suit me. The ZW1-E is actually much closer to where I'm going. There is also the Scoot Coupe scooter-based trike out from Panda Motors:
like some of the scratchbuilt tube space frame trikes on YouTube for their ideas. They are ICE powered, but much more closely follow the ideas of minimizing weight and drag. Also, some good examples of what not to do. Its worth searching for "Reverse Trike" to see what comes up.

Anyway, everything people are doing is cool, I really like to see the progress, and I have my own problems to figure out if somebody cares to chime in.

Here are a few guidelines I'm following, and the state of my project. Not saying this is gospel or anybody else should be going this way, or even that I'm right about any of it, just my design principles and status:

1. A gallon of gas is about equal to 8 kwh of lithium. Don't hijack this thread to argue about that. Its a guiding principle useful for planning.
2. An efficient Lithium-based EV should be around 50% battery by weight. Pb-based cars are way more as a percentage, but I will be quite satisfied with anything over half for Lithium.
3. I don't know how the design parameters scale, so I'm starting small because it is cheaper and easier- a single seater to start with. Nothing here about desirability or the merits of larger versus smaller vehicles- I have a 3-seater and 5-seater on the drawing board- I'm just heading where my budget, skills and risk tolerance are demanding I go.
4. I think I can make a 3 wheeler that weighs under 400lbs, 200 of which is lithium. Markcycle's hub motor, liquid cooled, makes this doable. It turns out 200lbs of LiFePO4 is a little more than 8kwh. So, at my design goals, I'm carrying the equivalent of about 7/8 of a gallon of gasoline, assuming some reserve to preserve battery life.
5. My project is to see how far my vehicle can go on that. Have a look at Craig Vetter's work last year to make a fairing that could get a Honda Helix from 60mpg to 120+mpg. He didn't come anywhere close to doing that, but the project is online and its a great primer on what's easy, what's hard, and what probably isn't possible with aerodynamics on vehicles of this size. At the end of the day, if I could get the equivalent of 75mpg, I'd have a 60+ mile useable range, which is satisfactory. I'm willing to trade some of that range for speed, and I live at the top of a 350' hill, too, so I think the balance between decent range and enough power to make the trike livable for me will be OK.
6. Current design parameters are:
--LiFEPO4 battery pack- currently leaning toward 34 eCity Power 80Ah cells- 108V nominal. (201lbs)
--BMS, wiring, lighting, instrumentation. (20lbs)
--Kelly Controller, fuses, charger interface, (charger is not on board) contactors, relays, pots, etc. (20lbs)
--Rear motorcycle swing arm suspension with brake caliper and pedal (25lbs)
--MHM602 hub motor, wheel and disc brake. (50lbs)
--Front suspension with disc brakes, wheels & tires (75lbs)
--Composite monocoque chassis, with hard points, attachments, interior and paint (100lbs)
--Water cooling system for motor and controller. (30lbs)

Obviously, if you look at my numbers, there are some major problems. First, even though each one of these numbers seems to me to be an absolute minimum value that I will work very hard to achieve- I'm still 90-120lbs over weight, depending on whether I go with liquid cooling. I also don't want to cut back on batteries to make weight, because the performance/range balance could slip away from me. I don't want a car that can't go 30 miles without radical driving techniques, or has to crawl up the last 1/2 mile to my house at a jogging pace, with my neighbors on my bumper every time. Lastly, the maximum curb weight for the MHM602 hub motor is 400lbs, and my design is built around it. I have to get the weight down somehow. I don't currently own most of the vehicle's component parts yet, and I may be able to get lighter stuff than I've seen and spec'd, but I have to get more knowledgeable about it. Still, I don't know how I'm going to get there. If anyone has any insight into these issues, please chime in.

In the mean time, I'm working on an unpowered 1:3 scale design study for packaging and structural integrities. As that comes together, I'll put it up somewhere...

Tom Alvary
Just a Tinkerer...
White Plains, NY

Interesting read Tom. I'd go the composite route, if I thought it would be as safe as a chromoly space frame. If we are going to be driving these things at 60mph then I want to be sure that if something (someone) goes wrong, that I've got a strong frame around me. Plus I can't get it through my head on how you would reliably attach suspension parts to a fiberglass frame. I appreciate what Markcycle is doing, but I don't think that his motor is suitable for anything but a small electric motorcycle. 10HP is just not enough and 2 of them would be $2500. I can get a forklift motor that will do 30HP for $150.00.

-Jim

Crashworthiness is an interesting problem. At the weight we are talking about, I'm not sure there is any significant difference in the (lack of) protection offered. A chromoly space frame in my weight class would be a bird cage. For larger structures, a foam core composite will do very well, but crash performance is a very complex set of problems. The easiest (and only really practical) strategy for the hobbyist is just to throw mass and structure and the problem in the hopes of 1) not being the loser of the basic physics problem when the masses of vehicles collide, and 2) trying to keep the impacts off of the passengers. If you can do some energy absorption (styrofoam bumpers?) or reduction of impact force amplitudes (crush?) that's great, but that work is serious engineering and it tends to be focused on one collision mode- running into things. Anyway, if you feel safer in a metal frame, that's the way to go for you. In this weight class, I don't think crashworthiness is going to be very good no matter how I build it. More important for me is to minimize design flaws, prevent mechanical failures, and to make sure I can see and avoid trouble driving it on the road. I test-drove a 1960s Lotus Elan convertible about 10 years ago, and the primary reason I didn't buy it was that it gave me a really creepy feeling to drive. It was just so small and flimsy that it made me paranoid. If my trike feels the same way, I'll trailer it to shows and play with it in controlled environments while I make something bigger.

The suspension pick-up points are a little unnerving, and that really has my attention, too, but its conventional enough construction. All airframes and monocoque chassis have hard points and attachment fixtures of one kind or another. Basically, I'll be bonding in metal plates and mounting ears that are loaded in shear. I'm in the process of finding out how much more complicated than that it really is...

I've been looking at small racing cars for my front suspension, and it seems the Formula Student (Formula SAE) cars have the closest fit in weight and dimensions to my vehicle. Unfortunately, those are engineering exercises and almost entirely scratchbuilt suspensions from university-based teams, but if I could buy one I would. If I could get a student who participated in such a project to work on my trike project, that would be cool, too. I really don't want to do all that from scratch, but the good news is a suitable and very light front suspension is possible.

The Markcycle hub motor solves some problems for me, but I think the power is OK so long as my vehicle stays under 400lbs, which is to say a small electric motorcycle, so we largely agree on its application. I, too, think using more than one of these motors makes little sense. For me, cooling it under the body is going to be the big issue.

Tom

I keep looking for the ideal featherweight suspensions (under 75lbs, including wheels & tires, for the front, 45lbs for the rear not including the hub motor) for my vehicle.

The Honda Odyssey/Pilot is an interesting candidate for the front. Three versions of these off-road go-carts (FL250, FL350 and Pilot FL400) had 3 different front suspension designs. What's cool is that their curb weight is right at my target, and

The first Odyssey (FL250) was a rather simple single trailing arm coil/over setup that was unsatisfactory off-road, but could be a real winner in a road vehicle. The later Odyssey FL350 is a twin trailing arm coil/over advancement of the original design, much like a miniature VW beetle front end, without the torsion springs, and also very promising for road use. The trailing arm setups are ideal in that their camber doesn't change though the suspension travel, and they are easily narrowed or widened. The design is also really great for packaging, as Dr. Porsche understood so well. My concern with these suspensions is that they may be too heavy. Both have drum brakes and beefy arms, which makes them durable, but they are 20+ years old and all steel, I think. I have a line on some of these parts and will find out what they weigh.

The last design (FL400, which was renamed from Odyssey to Pilot) has a proper unequal-length A-Arm set up, and seems really nice. This is similar to many quad ATV designs, but with a flatter and more road-like stance. This is no doubt lighter and better engineered than the earlier Odyssey bits, but still with the drum brakes. Finally, there are conversion kits by at least two makers (racers, really) for a-arms to fit the FL350, which is more common and cheaper than the FL400. I don't think I'm interested in any of these stock or aftermarket a-arm variants, because the real problem with all this 20-25 year old Honda stuff is that these carts were never very common, and they have become quite collectible and expensive. A matching pair of mint Pilot PL400 carts just sold on ebay for the whopping sum of $16,000! Really nice ones are close to $5k. That's huge money. A few hoarders have collections of parts they sell for big bucks. Hundreds of dollars for what are essentially wear parts. Unless those PL350 parts are light weight and relatively inexpensive, or I stumble across an Odyssey roller for proper used-toy money, I'll use quad ATV stuff.

The one part of the Odyssey I might just spring for, though, is the unique yoke handlebar unit. All the switches and indicators were on it, as was the throttle, two brake levers and both master cylinders. Very slick, indeed. I could even use the start button for regen braking. Odyssey parts cost silly money, maybe, but in this one particular instance it might be worth it...

I'm gradually making one of everything for my 1:3 scale packaging study. I found this fantastic "95th Percentile" human numerical model that just blew me away. The Formula SAE design series uses it as a minimum size for their racing series. Every car must accommodate this "anthropometrical data model” to be in compliance with the rules (or be penalized.) Google "Formula SAE 95th percentile model" and you'll find the dimensions in a little table. How big is a "95th percentile" driver? From the SAE: "The dimensions given in the Rules represent a 95th percentile North American male. He is 186.7 cm (6 feet 1 ½ inches) tall, weighs 102 kgs. (225 lbs), and has an erect sitting height of 97 cms. (38 ¼ inches). (The 95th percentile British male is ½ inch shorter and only 38 inches in sitting height.) An additional 5 cms has been added to this sitting height dimension to allow for the crash helmet, the top of which is approximately 2 inches above the top of the head." Wouldn't you know it, I'm 6 feet 1 ½ inches tall, and 230lbs. Unreal. I'd like to get that weight down, and my legs are longer than my torso versus this model, but now I know how to make room for myself in the 1:3 model without buying software I don't understand...

I'm also looking at rear suspensions. I am concerned that even though a swing arm from a light motorcycle is built to put a lot more than my 10-12hp to the ground, and is sized take a lot of pounding up and down, it isn't designed to take the side loading I'm going to put on it. Specifically, in a moderate-fast sweeping turn, I'm going to put significant cornering G laterally into the rear tire. Since it will remain vertical and not be leaned over like on a motorcycle, all that force is going to wind up in the sidewalls, then the spokes, wheel bearings and finally the frame mounts of the swing arm and spring/shock unit(s.) I'm worried I could pull the tire off the rim, break spokes and collapse the rear wheel, bind and/or bend the swing arm or linkage, or tear the whole rear wheel assembly- swing arm, shock(s) and all- right out of the hard points in my composite chassis. Likely failure mode would be a big bump in a fast corner, where the rear would begin to step out as the chassis rises and the suspension unloads, and then all that side force spikes as the chassis settles back down on the spring and laterally loads the tire. Its unpleasant to imagine, and a very disappointing discovery, as those small 125-250cc class swing arms are about the only way I'm going to make weight. Worse, the lightweight motorcycle rear suspension and hub motor drive package may be unsuitable for my application altogether. Trouble in River City, and for right now I'm not willing to redesign the whole vehicle...

My solution will be to fit a really skinny rear tire, maximally inflate it, and drive the trike like an airplane taxiing on the ground until I can instrument and observe what is happening.

Very well thought out Tom A! Here are some (admittedly dangerous) "arm chair engineer" observations...

There are a lot of "bolt the whole damn bike to the frame" style trikes out there like the tri magnum, etc, etc so I wonder how common swingarm failure really is. I seem to remember a guy who usually names himself conceptrqs (I think) mentioning he actually failed one but in economy mode IE no road race courses, my gut is telling me it should be ok.

as for quad suspensions, I agree. I am building a 1 seater now, 1/2" square tube main frame with thicker roll and dash hoop exo frame. using a raptor 600 front end, very light, I think about 60 or 70lb with wheels. I have some frame pics up at tshtrikes.com

The things that concern me some are the now fairly extreme ball joint angle running them "flat" and the brakes are very thin, very, very thin...

Ok, here comes some EXTREME armchair engineering. I have done a bit of googling about the raptor brakes, and in the atv sport you can mod just about anything, virtually any part, but no one seems to have an "upgraded brake kit", outside of braided lines. is this evidence they work well? I have to imagine with the 500lb these things weigh and 2 riders these things sometimes carry sometime, someone has to have stopped hard and was satisfied, time will tell, like I said, they seem thin.

Ok, crazy idea number 97, whole new layout possibly for the next trike.

Thinking about Marks motor and how to build a VERY inexpensive 1 or even 2 seat vehicle around it.

NOTE I am about to commit sacriledge in like 2 minutes... by suggesting a "traditional" 1f2r trike lol

Ok, how about this:

a front forks setup from a stout bike, say a sporty 1000 40 something milimeter. one of marks motors up front (or an etec or perm mounted to the bottom part of the forks on a perch that site just above the wheel, travelling with it, running a chain to a sprocket sitting on what was one of the rotor mounts)

lightweight box frame, possibly a 17" wide by 6" high "box" with the exo frame like Im doing with the current one. put the batteries low and to the rear to help with good balance.

the 'el cheapo piece de resistance"? a 4' wide diy trailer axle on slipper springs in the back, about 200$ brand new with wheels, brakes and all.

sit the whole thing under a blue sky designs electrathon body and canopy http://www.blueskydsn.com/kit_aero.html

ideas? thoughts?

Thanks for the feedback.

My trike is significantly different from both the IndyCycle-type and raptor/T-rex type designs, but I agree with you in that in a larger class of vehicle- a superbike swing arm is probably OK.
I will continue to worry about my contraption until I'm satisfied it is strong enough, particularly the composite chassis and its hard points.

I'm also on the same page with you on the brakes. They have plenty of swept area for good one-stop performance, just not enough beef or ventilation for extended use. I'm counting on regen and careful driving to avoid overheating them and preserve their useful life.

In the last 24 hours I've locked in my suspension components: 1985-6 Suzuki LT250R front end, and 2005 Yamaha YZ125/250 rear swing arm/shock. The Suzuki LT250R front end is very light, and not designed with the a-arms at big angles to the ground stock. That seems to be a long-travel/high-clearance feature of later-design ATVs, and the Suzuki is a little old-school in that department, (flatter,) and cheap now that it is 25 years old. There's more trouble with running these suspensions flat than just the extreme ball joint angles. There are adverse camber changes created, too, and maybe some bind. I'm going to try not to operate the Suzuki front end too much flatter than it was originally used. I may also upgrade to the LT500 Spindles, because I can change the Ackerman angle on them just by replacing the steering arms, since they are just flat plates that bolt to the spindles. I need to do that because my trike has more than double the wheelbase of a quad.Now I can model all these pieces in 1:3 and complete the design study. I may also buy frames from both the quad and the dirt bike to weld together as a test mule. Then I can sort out the bugs on the drive, brake and steering systems before I build the composite chassis. Seems like a sensible thing to do, but money is tight for the project and those are just two of several unplanned expenditures...

As for Idea No. 97:

I don't recommend putting Mark's motor on a steered wheel. Too much gyroscope effect for my taste. Other than that, its a great idea, but like everything else that uses mild steel and auto parts, its going to be quite heavy. If you go that 1F2R trike route with those materials, think about a Trimuter. Here's a link to a really great one from Scot Wilson. With Iithium, this thing would be awesome. The rear is a Datsun 510 IRS:

http://www.evalbum.com/2321

Thanks so much for the Blue Sky Designs link. I didn't know where BugE got their canopies from, and this is a great aero parts source. I might even consider starting with their bodywork and section it for my purposes. That might save a lot of time...

Interestingly enough, "Crazy Idea #97" is more like "Crazy Idea #1" than you might have imagined.

The first self-propelled road vehicle, the Cugnot from 1769, used exactly your proposed configuration, although it was steam powered, with the boiler over-hung ahead of the front wheel.

Of course, Joseph Cugnot crashed it in 1771, but I think it was as much an issue of its NO BRAKES configuration as the squirrelly "front hub motor" handling:

http://lostbiro.com/blog/?p=249

Here's another, the "Drymer":

Tom A, We should talk, because I like your style
back to "#97" I wanted to clarify, im talking about likely a 1 seater, mild steel frame and light duty trailer axle. (probably about 400 or 500 pounds total ) I can see your point about the gyro forces on the hub motor, dumb question, would a chain driven "external" motor on the front present the same problem?

side note on the Tri Muter, I dont know if this is fair, but I had a Tri Magnum (killed one of my mechanics friends) and it was so tiny on the inside, no way 2 200 pounders were ever fitting in it...

I just had one of those "holy crap" moments when the world opened up many times larger than I thought it was, and also validated much of my thinking.

First, I found this great site:

http://www.reversetrike.com

No doubt, this is the most complete compendium of what is out there. Lots of small reverse trikes, too!

Then, I stumble across a HPV (Human Powered Vehice) design there, and through that I discover a whole genre of vehicles that I only vaguely knew existed- Velomobiles. I have seen one or two of these over the years, but I had no idea about the variety and sophistication they are currently up to. Powered by cyclists, these trikes are around 1/3 my weight, half my size, and making do with less than 1/10th the power of Markcycle's hub motor. I'm giddy looking at them all. This appears to be a big Scandinavian thing. No matter. Here's the place to start:

http://en.velomobiel.nl/links/

What's fascinating to me is how closely they all are approaching the aero issue- their power/drag/weight issues are so critical, there's no room to fool around. I'm elated looking at them. I find it interesting that they don't seem to care if air gets under them. That won't do for me- I don't want air under my vehicle. I also notice the Aptera is similarly configured up and away from the ground. I'm no aerodynamicist, and I'm not being critical, I'd just like to know why everybody isn't keeping air out from under their vehicles...

As for the Trimuter- yeah, its really tiny inside. Both my wife and I are over 6' tall and over 400lbs between us. That's a very tight squeeze, indeed, and much of why Scot's Trimuter isn't in my garage. Too bad about your friend and the Tri Magnum. I always liked that design.

Anyway, I'm more optimistic than ever seeing so many vehicles that are around, and way below, my curb weight. I like their ideas, and looking at them hasn't made me rethink any of mine, either.

Cool...

The reason they are "putting air under there" is because they are trying to minimize ground effect drag. (BTW, I'm an aerodynamicist, MSAero Engineering Univ. of Michigan, '93).

Hey, that's awesome, thanks for the info. Go Blue.

I'm not sure I said "putting air under there" but what I meant was "not keeping air out of there..." I'm very interested in what the velo guys are doing because it works at the speeds one sees in traffic- like 0-50mph. I'm excepting the fully faired recumbent racing bikes for a second here, because they have such tiny envelopes and are so impractical (a couple or three people have to catch your bike and cut you out of many of these things, lest you fall over stranded like an upside down tortise...) that most of what they are doing with air flow can't be translated to a road electric trike of my size or larger.

I'm assuming this technique to reduce ground effect drag drag works primarily where:

a) you have a really small cross-sectional area, so getting the body up that extra few inches off the pavement has a significant impact on reducing the ground effect drag;

b) the cross-section of the vehicle is mostly vertical, like a bike, or roundish, like a velomobile, but in any case not primarily horizontal, like a car or trike with a wide body; and finally,

c) reducing ground effect drag is more important in that application than not generating (adverse) lift.

This last issue is completely understandable on a bicycle, but less so on something like the Aptera. There's a special case, that Aptera. It is supposed to go 85mph, and I sure would like to see someone shake it down at that speed in gusty crosswinds before I tried it. It looks a little too much like Frank Lockhart's Blackhawk for me. I'm sure it is superbly aerodynamically engineered and safe as a potato at 85 and under, but I'm going a different way and I don't know the science of wheel pants and a shaped underbody. One day I'll want to be see how fast my little speedster might go with as much juice as my motor can stand. It could go 100mph; and with a different motor, even faster than that. I think all of these velomobiles and any amateur attempt at an Aptera-like body, if not the Aptera itself, may leave the ground and pirouette through the air at such speeds. OK, maybe not, but loss of control due to aerodynamic instability is a failure mode I must avoid, and I'll be trying to go faster than any of those other trikes. That's why I'm not inviting the air under my trike.

Call it the easy orthodox way around a complex set of issues I'm really incompetent to solve. I'm not really being critical of other designs, I don't have the qualifications to do so, and that isn't my point. I'm sure they have done their homework and their vehicles are right for their applications. Just thinking for myself, here. The full measure of ground effect drag created by keeping air out from under my trike seems well worth the benefit of not generating lift at the front of it. I'm not a bicyclist for whom drag is the enemy, I just don't want much of it. Of course, the bodywork could still generate lift at speed, but it seems a lot less likely than if I tried to maintain/manage laminar flow on the bottom of my vehicle with the ground a few, variable inches away. I figure the rear may indeed generate some unwanted lift, but I can control that with a spoiler or even a horizontal stab if its really a problem. I'm just incorporating what racers have been doing (without checking the math) for many years: First, keep the air out from under the front of the car. Also, produce some downforce over the front wheels. Finally, try to reduce pressure under the back of the car with a diffuser of some general sort, and, when in doubt, spoil the airflow where necessary to (basically) trade lift for drag. That's all I really know how to do.

I'm in the throws of another tricky aero problem, too. On my drawing board are symmetrical NACA airfoils- NACA0022-NACA0024 to be precise, and while any of these would make an efficient and beautiful teardrop streamliner, they will either result in a really narrow front track that is likely to roll over if it gets out of shape on the road or into a ditch, or the trike will wind up 20 feet long, and then I'm overweight. I don't want to put the wheels outboard for a number of reasons, so I'm trying to squash the frontal area generally flatter to widen the front track, and still wind up with a vehicle length somewhere around 4.5 times that diameter. Of course, the"diameter" of frontal area is a derived number, because the shape isn't a circle. The worst thing would be to wind up with a squirrely, narrow front-ended chassis than wasn't quite narrow enough to be efficiently slick. Compromises are the way one proceeds here; I just don't want to end up with a bad one...

At the end of the day, I'm going to follow the conventional wisdom wherever I can divine it- (things like: most of the drag on a modern road vehicle is generated aft; keep the air out from under the body; a Kamm tail on a proper tapered shape is better than a fat, pointy tail cone; a diffuser should be 11 degrees from horizontal; etc. etc. etc.) There are exceptions to every one of these and many other shibboleths, and I know it isn't that simple, but I also know it isn't rocket science, and I can be close enough to the ideal on most of these things to meet all of my design goals without finite element analysis or 3D modeling. I'm also willing to try different things. Its a hobby, yes? I can always (and will) put tufts of yarn all over and see how its going. My patron Saints are Pinin Farina and Jack Northrop- both of whom worked largely by eye.

Anyway, am I generally on the right track with this "Aero 101 for the boy whose last name isn't Arfons" thinking, or am I missing something I just don't know that would make a big difference for me?

Tom

Again Tom A, Its great to see your well thought out posts.

I may be the one guy who is less aero aware (and who wants aero to play a part in making his trike work well)

I am operating under a few assumptions right there in "the middle"

If my trike is about 9ft total in length, the nose would be fairly abrupt, and a smaller "teardrop" would be formed at the bottom, say most of the portion of nose just ahead of the wheels to about 2/3 of the lower body behind the wheels. letting the natural curve up happen as the frame gives way to the swingarm then up to expose a portion of the rear wheel. also outward from the centerline because in a side by side 2 seater, the "butts" are about 39" and the shoulders require a bit more inches.

Sooner or later I will get a drawing scanned and up.

On another note, There is another issue I may have come up with a fun answer to, Its overall height. Tom A, I imagine that you (as I will) be utilizing the easiest direction to go in a trike, and that is down. my design calls for 5" total overall ground clearance, with an overall height, just behind the drivers head of 34"

(for comparison, the lotus elise is 43" high)

So we start singing the same safety song as the tadpole guys, the one that goes like this:

"Oh what pretty door handles you have mr honda civic" If only you could see me" lol

Then theres the issue of people seeing your directionals, brake lights etc.

Lastly, when getting the trike that low, its tempting to get the roll bar height just at "head level" which means in a rollover, to survive, those harnesses better be tight.

so...

For my rollbar, I am going to run 2 aero section steel bars up to 45" and build a wing spoiler off of a lightweight beam connecting those 2 lengths of aero section the forward half, all wing, the back half directionals, brake lights under clear plastic and faired cdi lights (wingtip strobes) to assist with visibility.

better roll protection, better visibility, adjustable spoiler, better visibility for brake lights etc.

Thoughts?

p.s. as I was finishing this post, I noticed "Tom A" and thought, since my name Happens to be Tom Bell, That makes me "Tom B'

Hey TomB:

Thanks for the ideas. I don't exactly understand your trike layout, but a 9 footer built for two is going to be pretty short and wide. I'll wait to see your images. My single-seater will probably be 14-16 feet long. When my first design study is done, I'll put it up for comment.

I have checked with the NY DMV, and indeed there is a minimum seat height applicable to motorcycles, but its a little unclear how it is to be determined. From Form MV-529B (10/07): "Measure from the ground to the top of the operator's seat. If the seat is adjustable, the seat must be at its lowest position. Seat height must be at least 25 inches from the ground on a two-wheeled motorcycle, and 20 inches on a three-wheeled motorcycle." So exactly what is the "top" of the seat? If you work at the DMV Technical Services Unit, are a NYS police officer, judge, or other person with experience interpreting or administering this rule, I'd love to hear from you. I have a strategy and a question or two about all this rule, but all I really need to do is call the special number at the DMV Technical Services Unit set up for homemade and custom vehicles and discuss it with them. Their phone number is printed right on the required equipment form. Nice. We shall see...

As for vehicle height- yeah, its going to be low like everything else from a T-Rex to a Tri-Hawk. I probably won't have 5 inches of ground clearance everywhere. I'll have to paint it white (which is the right color for the foam-core monocoque anyway,) with da-glo stripes or something and fit some Italian air horns. There doesn't seem to be a minimum headlight height applicable, and I haven't decided what to do about lighting yet. Because of the seat height requirement, I may wind up pushing the operator up in the chassis, which would result in a rather tall skinny profile, like a stretched Corbin Sparrow or a smoothed out Freeway. I'm 36" to the top of my head seated upright on the ground, but my driving position will be slightly, maybe mostly, reclined. The trike must be operable with a helmet on. I'll probably have make both open and closed canopy options for the cockpit. I will have some rollover protection, but it will come from the monocoque shell itself, with no steel steel reinforcement considered at this point. I'm working on my 1:3 scale me model right now, and waiting for suspension components to arrive. When they get here, I can make enough component patterns so all these relationships will become clearer.

Its quite a tricky little puzzle, actually. I'm already seeing where the ATV a-arm suspension is a little too wide and could be made narrower and lighter, and of higher quality materials. I have that awful suspicion than nearly everything I touch that wasn't made for this trike is going to fall into that category- "Great as a pattern, but what I really need is smaller, lighter, and has to be hand made from expensive stuff..."

Tom

Oh, yeah, here are the ultra-cool USAF cockpit design anthropometric documents I'm using to construct my operator model.

For guys like me who still actually cut and paste (Titebond II glue, thank you very much...) and model in 3 actual dimensions, its a treasure.

The Manikin figure is the 5th Percentile Male, with two sets of longer arm and leg options included for creating more variation. I used the short arms and legs, and blew the whole thing up (about 300%) until the figure was a little bigger than me in 1:3 scale. Note how the dude is already wearing a helmet, which is something I needed to include for my model. Unbelievable...

Tom