High performance & durability Cannondale Semi Recumbent
- Thread starter neptronix
- Start date
Sounds like assembly of your project is quickly approaching the final countdown!
Is it feasible in your planning to do some top speed tests with and without the aerodynamic improvements? I’m interested in getting an idea of what kind of real world efficiency can be gained.
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Is it feasible in your planning to do some top speed tests with and without the aerodynamic improvements? I’m interested in getting an idea of what kind of real world efficiency can be gained.
Sent from my iPhone using Tapatalk
www.recumbents.com
10 kW
+1 to tailbox, especially above 25MPH. Although it seems illogical, a simple front fairing won't give you much if any speed gains.
www.recumbents.com said:
I wasn't aware that the rear was that important!
Anyway, the leaf motor is in. I've never seen a Chinese company do this good of a packing job, so hats off for that.
However, not exactly stoked about the radial lace job. But we have 12 gauge spokes here, and my bike is designed as such that more of the weight is forward than usual, so maybe it's not a big deal. I have a nice 16 x 2.75" tire to throw on this bad boy.
ScooterMan101
1 MW
What guage wire are the Phase Wires ?
What does it weigh before the freewheel / brake disc rotor ?
What does it weigh before the freewheel / brake disc rotor ?
dequinox
10 kW
Wow what a cool project, and what a cool surgery (I just mean technologically speaking, not cool that your lot in life required you to go thru it)! I hope your mending is still going well, I read thru the highlights of this thread and it sounds like your ahead of the curve, so well done.
A thought on goat heads, not to beat a dead horse: have you looked into Schwalbe marathon plus? They are more of a touring tire, and I don't know if they come in 20"or not, but they do have Kevlar banding and an extremely thick gel (like gel insert, not sealing gel) layer. I went a good 5k miles on a pair and only had one or two flats... One was a shard of glass that had apparently worked it's way in after initial embedding, and the second i think was a sharp bit of rim on the inside that did the tube in. That maybe in combo with a "thorn resistant" tube, and you might have a passable combo. I realize your already passed design freeze and into build already, but for others i thought this might prove useful. I grew up in Central Oregon and those f***ers were everywhere!
A thought on aerodynamics: yes great importance is placed on the rear end of any object when attempting to reduce drag when moving thru a fluid. One of the best demonstrations of this is those weird flaps on the back of some semi trucks. There goal is to reduce the formation of any vortices and avoid flow separation. A good old fashioned explanation is available here: https://youtu.be/j0rQ4F3f-Ic
Maybe skip to about 4 minutes, it's quite the uh... paced ... introduction...
I think he covers the drag equation in this series eventually and talks about how each term is affected by the geometry you choose.
Good luck putting this together, and pay extra attention to this drop outs given the ungodly amount of power you're going to stuff into it!
A thought on goat heads, not to beat a dead horse: have you looked into Schwalbe marathon plus? They are more of a touring tire, and I don't know if they come in 20"or not, but they do have Kevlar banding and an extremely thick gel (like gel insert, not sealing gel) layer. I went a good 5k miles on a pair and only had one or two flats... One was a shard of glass that had apparently worked it's way in after initial embedding, and the second i think was a sharp bit of rim on the inside that did the tube in. That maybe in combo with a "thorn resistant" tube, and you might have a passable combo. I realize your already passed design freeze and into build already, but for others i thought this might prove useful. I grew up in Central Oregon and those f***ers were everywhere!
A thought on aerodynamics: yes great importance is placed on the rear end of any object when attempting to reduce drag when moving thru a fluid. One of the best demonstrations of this is those weird flaps on the back of some semi trucks. There goal is to reduce the formation of any vortices and avoid flow separation. A good old fashioned explanation is available here: https://youtu.be/j0rQ4F3f-Ic
Maybe skip to about 4 minutes, it's quite the uh... paced ... introduction...
I think he covers the drag equation in this series eventually and talks about how each term is affected by the geometry you choose.
Good luck putting this together, and pay extra attention to this drop outs given the ungodly amount of power you're going to stuff into it!
Is it a motorcycle / moped rim? Or a bicycle rim?neptronix said:
If the former, the 12g might work ok, if they've been tensioned correctly for their gauge. If they haven't, then they may loosen as you ride, and break (probably at the elbows).
If the latter, then even with the eyelets the tension needed for that size spoke may damage the nipple holes (may be concealed by the eyelets, tiny cracks) which then allows the spokes to loosen, and retightening them further damages the holes, and so on.
I've experienced both these problems; it's exacerbated by greater weight load (and/or shock / bump loads).
If it is a bicycle rim, you may be better off with 13/14 butted spokes, if you can't use 14g straight spokes. I've been using the 13/14 Sapims from Grin Tech with the ex-Zero rims from Ypedal on my rear wheel of CB2 and both rear wheels from SB Cruiser. Never any spoke problems, even with pothole impacts that seriously damaged the rims. (though I had to retighten spokes after the rim damage due to the bent rim loosening things up...but no further loosening after that, as the holes weren't damaged).
MIne are also radially laced, and it works for the heavy cargo duty mine see.
Ride it for a while and see if the spokes loosen up; it'll tell you at least if the wheel was built right to start with.
(or check the spoke tension first, if you have a gauge for that, or can borrow one from your LBS).
Chalo
100 TW
As far as I can tell, radial lacing of a drive wheel is not a reliability issue when the hub and rim are close enough in diameter that you have to use it. Because the lever arm from axle center to hub flange is so long, and the spoke so short, windup is miniscule. It certainly seems to cause fewer problems than cross lacing when the spoke insertion angle is iffy.
I use 68mm 14ga radial spokes on my 20" wheel with a Crystalyte 5305. I've had no problems at all. They all stay tight, and not one has broken.
My guess is that if you have problems with spokes loosening or breaking, it will be more attributable to the Lincoln Log spokes than to radial lacing.
I use 68mm 14ga radial spokes on my 20" wheel with a Crystalyte 5305. I've had no problems at all. They all stay tight, and not one has broken.
My guess is that if you have problems with spokes loosening or breaking, it will be more attributable to the Lincoln Log spokes than to radial lacing.
ScooterMan101 said:
Too small! 16 gauge, according to my wire strippers. The second i get a a replacement soldering tip in, i'm hacking those wires off, an inch from the axle, and replacing with 12 gauge.
ScooterMan101 said:
Just about 16lbs, which is not a surprise at all. The motor would be about 14lbs itself, which is in line with what the MXUS 30mm wide DD hubs weigh.
amberwolf said:
Looks like a bicycle rim. It's a 'power circle' brand. Aka China's relabeled factory seconds :lol:
amberwolf said:
Yeah, i'm gonna have the spoke tension checked and just ride the damn thing. If it doesn't work out, i'll go with sapim 13/14ga on a higher quality rim. Getting the motor with a completed rim from China was so cheap that it was worth the bet.
If i did not have a big fat squishy rear tire, rear suspension, and a forward biased weight distribution ( relative to the bike's geometry ), i think i'd be a lot more nervous about this crappy spoke setup.
It is a negative towards the idea of building a very high reliability bike, and the spokes are way too stiff, but whatever. Big 2.75 x 16" moto tire > the positive ride effects that come from spokes that have give in them.
Chalo said:
I'm really surprised that a bigass motor like that is fine on 14 gauge spokes and radially laced. Likely only possible to get away with this on a 20 inch wheel!
Yeah, i have seen plenty of snapped spokes from funny angles with crossed lacing..
dequinox said:
Thanks. I'm healing at a pretty good rate. Currently teaching myself to walk without a cane. It's an interesting process because i have almost zero muscle on the inner side of the leg that was operated on. I can already see the inner leg muscles get physically larger after a week of really pushing them
I just feel lucky to have identified the problem and convinced someone to operate on me. A good percentage of people you see walking with canes or are stuck in wheelchairs have twisted bones - likely the cause of their arthritis as well. Western medicine is generally retarded about this stuff. Yet another area where we drop the ball!
dequinox said:
Yes, i used to scream from the rooftops about how cool the Marathon Plus was, on this forum.. They worked really well in northern Oregon for me.
All things changed when i moved to Utah. On some rides, i find hundreds of goatheads in my tires after. The longest one i've measured from here is ~10mm! I've spent ~$500 over time on various tires and tire add ons and concluded that more rubber was the only good answer. Here are a couple threads for the back story on that.
https://endless-sphere.com/forums/viewtopic.php?t=89469
^-- a visual demonstration of why the marathon plus is not all it's cracked up to be ( for my conditions, anyway )
https://endless-sphere.com/forums/viewtopic.php?f=2&t=97992
I throw another couple hundred dollars at trying to find the most durable motorcycle tire, using the same 'thumbtack through the tire' demonstration.
dequinox said:
Interesting vid, thanks for sharing! I'm pretty stoked to build a rear aerodynamic aid.
Chalo
100 TW
neptronix said:
I'm surprised that the spokes stay tight as well as they do. 14ga spokes are about twice as elastic as 12ga spokes, but 68mm spokes are only about a quarter as elastic as full length spokes in a full sized wheel. So the very short length is an even bigger problem than thick spoke gauge in terms of the spokes' ability to maintain tension.
P.S., re:
The range of elasticity in a spoke is not discernible in ride quality. It's a very small dimension, even in the thinnest spoke. On top of that, the rim is going to flex and move according to the load on it, whether or not the spoke can follow along. Spokes can't push on the rim; they can only pull. So if there's any detectable suspension quality to a wheel (which I doubt), it's from the rim and not the spokes.
The reason you want thin spokes is so that as the rim moves, they can maintain some tension and not go completely slack. When they go slack, the nipple is (for a very brief moment) free to loosen a little bit. Multiply by countless bumps, side loads, shocks and heavily loaded wheel revolutions, and the nipples can unscrew completely. Spokes that don't have tension, can't support the rim. So you not only get an out-of-true wheel, but a wheel that's more susceptible to bending or collapse.
A fat tire does have a dramatic effect on ride quality, but it also has a benefit for wheel integrity. The fat tire spreads loads out among more spokes in a longer section of rim, and it attenuates the peak forces transmitted from the ground to the wheel. The result is the same wheel stays truer, and its spokes maintain their tension better, when you use a fatter tire.
dequinox
10 kW
Cooooooollll... like medium-term hulk type stuff! :lol: That must be incredible to see your body adapt on such a time scale!I can already see the inner leg muscles get physically larger after a week of really pushing them
Yes, root cause analysis is an art lost on most. Especially in medicine. The faster way to "fix" someone is by simply treating someone for the most common cause of the symptoms, and work your way into the more obscure if it doesn't work.
Well sheeeit. I don't think I've ever seen one quite that large... there is always these tires I suppose?
Thanks for the links, it's good to know that these have been looked at so thoroughly. My experience was good, but my riding conditions are favorable... i.e. no goatheads generally (Eugene, OR).
Yeah he's dealing with the really basic stuff, like pressure drag vs skin drag (that latter concept was demonstrated by the round ball vs the teardrop in glycerin).
There are more general articles everywhere you want to look. Engineering toolbox has a primer on the drag equation for moving vehicles (mostly) here: https://www.engineeringtoolbox.com/drag-coefficient-d_627.html
I'm using the MXUS 4504 and 4503 in my trike's wheels.... Back when I ordered the spokes for those wheels, if Grin had had plain 14g (or even 15) spokes with nipples that would've fit right in the eyelets of the rims I'm using, I'd've gone with just 14...but the 13/14 is close enough, wiht most of the lenght 14, and just the jbend end at the flange bieng 13. (didnt' wanna deal with washers and the doublewall rim holes, etc)neptronix said:
dequinox said:Cooooooollll... like medium-term hulk type stuff! :lol: That must be incredible to see your body adapt on such a time scale!I can already see the inner leg muscles get physically larger after a week of really pushing them
Yeah. Known as 'noob gains' in the body building world. I'm just stunned at how fast it happened. Especially on the left leg. I never had inner quads on either leg, and my left leg, which has been pulling overtime shifts, is now completely balanced.
dequinox said:
I'll spare you the long story but if you look at my youtube channel there are lots of stories about how the medical world got me wrong and i figured shit out myself after going on months/years long research rampages and even pouring through some of the textbooks physicians of different stripes have to read.
Thanks for the links, it's good to know that these have been looked at so thoroughly. My experience was good, but my riding conditions are favorable... i.e. no goatheads generally (Eugene, OR).
That's a crazy ass tire. I've seen those sort of airless tires many times and wondered if they could handle the speeds my roads require me to travel on. The answer is usually no.
Yeah, most people don't understand the conditions here and i've had to explain myself till i'm blue in the face whenever i bring it up.
Eugene is a beautiful place i'd love to do some riding in.
Chalo
100 TW
neptronix said:
Then there are those of us who've ridden tens of thousands of miles in the city, in the 'burbs, in the sticks, and toured multi-day interstate routes. Who understand that your need-for-speed problem is located between the seat and the handlebars.
www.recumbents.com
10 kW
So it's going to have a motor on the front wheel? That should be interesting. Have you checked the front/rear weight bias? I think that front wheel is going to be fairly lightly loaded. I can't imagine you'd have any spoke issues though you may be able to do some gnarly FWD burnouts.
ScooterMan101
1 MW
Interesting, How much resistance will be in the 16 awg wires that are left in the motor ?
Won't they heat up for the amps you will be pulling through them ?
Would like to see an electrical engineer compare the difference in the ability between replacing the phase wires from the inside of the motor to the controller
and
leaving the 16 awg in the motor and one inch outside the axle and splicing in the 12 awg to the controller .
Won't they heat up for the amps you will be pulling through them ?
Would like to see an electrical engineer compare the difference in the ability between replacing the phase wires from the inside of the motor to the controller
and
leaving the 16 awg in the motor and one inch outside the axle and splicing in the 12 awg to the controller .
neptronix said:
No front motors here. Absolutely not! When i say 16" wheel, i meant 16" in motorcycle size. Aka the rear.
It would be cool to utilize the smaller front wheel for an even crazier power density, but there are just too many problems with the front end of the bike.
Anyway, i had the spoking on the leafbike motor wheel checked, and my trusted wheel builder dude says it's perfect, but the rim itself has 1mm of hop. Admittedly the 26" leafbike 1500w i ordered in ~2014 had the same brand rim and same minor 'hop', and i pulled 60mph on that hub wheel, so i think i'm fine with a bit of hop here at a peak of 45mph. To be expected with a super cheap 'power circle' rim.
Em3ev has been ultra slow to get me a battery and it's taken some weeks to even just order a battery. Longer than a week to get the item they have in stock shipped. I am not even certain if the 15ah 48v batt i currently have can drive this motor, so the battery will probably hold getting wheels spinning up.
Will get a kV measurement on the 3T 1000W motor this weekend when i have time to get into the garage. My guess was that it is 18kV.
It would be cool to utilize the smaller front wheel for an even crazier power density, but there are just too many problems with the front end of the bike.
Anyway, i had the spoking on the leafbike motor wheel checked, and my trusted wheel builder dude says it's perfect, but the rim itself has 1mm of hop. Admittedly the 26" leafbike 1500w i ordered in ~2014 had the same brand rim and same minor 'hop', and i pulled 60mph on that hub wheel, so i think i'm fine with a bit of hop here at a peak of 45mph. To be expected with a super cheap 'power circle' rim.
Em3ev has been ultra slow to get me a battery and it's taken some weeks to even just order a battery. Longer than a week to get the item they have in stock shipped. I am not even certain if the 15ah 48v batt i currently have can drive this motor, so the battery will probably hold getting wheels spinning up.
Will get a kV measurement on the 3T 1000W motor this weekend when i have time to get into the garage. My guess was that it is 18kV.
ScooterMan101 said:
The remaining 10% of the 16 gauge wire will create some heat, but it'll get soaked up by the other 90% of the wire that's 12 gauge, and not getting hot, because the majority of the current path has significantly lower resistance.
I may only see a ~1% efficiency gain ( at full speed ) by thickening up the wires. Replacing the 2-3 inches of 16 gauge would only net me ~0.1%. Really not worth all of the hassle of tearing the motor apart, and figuring out how to shoehorn thicker wires.
The motor will not see high sustained amperage, so there's little use in even thickening up the wires much. The main reason for using oversized wires across the board on this build is to maximize the efficiency of the power bus, as ultimate range is the goal here, and i'm also running a high amp, low volt setup here.
www.recumbents.com
10 kW
neptronix said:
Ah! Motorcycle 16". That makes more sense now. :lol:
If you did want to replace the whole cable all the way inside the motor for whatever reason, Grin Tech has 3x12g+7smaller conductors cable. I've got some here and it seems good enough; will be installing it in the old Stromer Ultramotor as soon as my back is ok enough to let me get it apart with the 3-jaw puller.neptronix said:
thundercamel
10 kW
Does the Stromer Ultramotor design not let you use this method to take it apart? Skip to 2:50amberwolf said:
Edit: I think I see, your motor splits in the center instead...
[youtube]yKMUg7qonhg[/youtube]
yepthundercamel said:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=86600