LightningRods mid drive kit

[LightningRods]

I trust you Matt!

The Big Block ships from the factory with a fan very similar to the one that E-G has shown on the 3220. It's made from black plastic instead of aluminum but the design is very similar. The can is closed so that's the first go-to for better cooling at high power.

So all radial fans are draw through rather than blow through, correct? With no blade pitch there is no direction of air flow other than outward from the center. Like you said the fan uses the centrifugal force of the air to create a low pressure area at the center of the fan. This is why they suck. In a vacuum kind of way of course.

 

[recumpence]

I trust you Matt!

The Big Block ships from the factory with a fan very similar to the one that E-G has shown on the 3220. It's made from black plastic instead of aluminum but the design is very similar. The can is closed so that's the first go-to for better cooling at high power.

So all radial fans are draw through rather than blow through, correct? With no blade pitch there is no direction of air flow other than outward from the center. Like you said the fan uses the centrifugal force of the air to create a low pressure area at the center of the fan. This is why they suck. In a vacuum kind of way of course.

You are correct.

Again, much of this is splitting hairs. Any airflow is welcome inside a motor.

If the blades were curved, airflow would be improved. But, flat blades on a radial fan, allow airflow no matter what direction of rotation is used.

Matt

 

[John Bozi]

I can fly with a motor without skill and knowledge.

[youtube]1kykW4p6D4c[/youtube]

 

[ElectricGod]

Take a vacuum cleaner apart. there is a reason the blade is radial.

The centrifugal force of the air is far higher than the pressure exerted by a pitched forward pushing blade.

The reason you do not feel much air puking into the front of the can is two fold;

#1 If is drawing air into the front. That is harder to feel than air blowing.
#2 The aire is pulled through the magnet gap in the motor. That gap is tiny. Not much air is pulled through.

Trust me on this, a radial fan pulling through the windings is the best method. that is why nearly all motor manufacturers do it that way, and why all vacuum cleaners use radial fans to pull air.

Oh, let me add this; a radial fan relies on high rpm top function. Assuming the rpm is high (typically over 6,000) a radial fan is best.

Matt

Sorry LR for taking over your thread.

Before I said anything, I wanted to be sure of my facts. Vacuum cleaner fans do not use straight, flat blades that radiate out form a closed center. They usually curve inwards to an open center. Air from the outer edges of each blade is "scooped" inwards and then exits out of an open center. This creates a compression effect towards the center of the fan. In a vacuum cleaner, the outer edges of the fan blades are pulling air in from the vacuum hose, thus creating the vacuum. The air exits out the center of the fan and into the bag or container. A flat blade that radiates outward from a closed center does not have this effect. It is more of a whipping or churning effect. It's better than no fan to be sure, but not as good as a vacuum fan. And to acknowledge what Mike said...with a curved fan you get excellent air flow in one direction and very little in the other. With a flat blade that radiates out from the center, it's rotation direction agnostic and as a result an equally mediocre fan in either direction. I was going to use a blower fan on my opened up big block. THe non-driven side would have a rectangular hole for attaching the blower to force air through the motor and the driven side would be opened up. If the non driven side was opened up and you knew in advance the direction of rotation (like in the all of Mikes kits), then an appropriately sized vacuum cleaner fan that turns in the correct rotation would be fairly ideal for pushing air into the motor for cooling.

Matt,
Where did you read that pulling air through was better than pushing air through a motor?

Edited to reduce redundant content. ;P

 

[LightningRods]

I had an extremely frustrating experience today that I'm hoping other builders can benefit from. I have a customer bike in the shop right now that I'm doing one of my rare full installs on. He's a local guy with a physical disability- he only has one arm. So I've been trying to help him out. His bike is really unusual, having been built by a local frame builder to suit his special needs. He also has it loaded down with all sorts of gizmos, safety lights, and assorted chingadera. I got his install finished today and it wouldn't run. It would start to and then quit. I took it back up in the shop, put it up on it's center stand and the motor ran perfectly. Another test ride- won't run. Back on the stand- runs great. Load the motor with the brake, lower the tire to the pavement and smoke it- it runs great. Another test ride- won't run. I finally noticed that if I pedaled and applied power that the motor would come on in surges. WTF? Once I realized that the surging was speed related it hit me- something was effing with the speedo pickup on the front wheel. When the bike was on the stand the wheel was stationary and no problem. I took a hard look at the front wheel and saw that the bike had four "Reelight" pads in the spokes, two to a side. I put a screwdriver up against the pad and it stuck. Magnetic. These Reelight safety lights use magnets to trigger the flashers on the forks. As bad luck would have it they were lined up with the speedo pickup.

So these magnets were sending large and regular signals to the speedo pickup that was freaking it out. I think I had the upper speed limit in the CA3 set to 999 miles per hour but that didn't matter. So a head's up. If a bike will run on the stand under load but not on test runs suspect something messing with the speedometer sender.

 

[recumpence]

I am not debating curved blades versus flat blades. I am debating pusher prop style blades versus radial blades.

Also, in a motor, there is very little room for air to move through the magnet gap. So, a flat blade works fine.

Matt

Oh, Mike, good find on that. I Have had similar finds on various builds.

 

[LightningRods]

Here is the cooling fan as it comes from the factory. Wouldn't it be better to mount the fan with the dam on the outside of the vanes to help move hot air off of the motor case?

I've been cutting the fan extension off of the motor shaft because there is no room between the pedal cranks on a bottom bracket drive. For a drive that mounts in a less width constricted area there is less of a reason to remove the fan. On the swingarm mount it would stick out where it could get smacked by something. Maybe not so good for off road.

 

[recumpence]

Here is the cooling fan as it comes from the factory. Wouldn't it be better to mount the fan with the dam on the outside of the vanes to help move hot air off of the motor case?

I've been cutting the fan extension off of the motor shaft because there is no room between the pedal cranks on a bottom bracket drive. For a drive that mounts in a less width constricted area there is less of a reason to remove the fan. On the swingarm mount it would stick out where it could get smacked by something. Maybe not so good for off road.

Yes, Mike, the dam should be on the outside to better direct airflow.

Matt

 

[LightningRods]

8)

 

[recumpence]

Actually, looking at the end cover, this fan is positioned correctly for this application. The fans pulls in air through the flat end of the plastic cover, slings that air outward, and that outward flowing air is directed out the edges of the cover cascading along the length of the fins on the sides of the motor can.

Not a bad design.

 

[ElectricGod]

Actually, looking at the end cover, this fan is positioned correctly for this application. The fans pulls in air through the flat end of the plastic cover, slings that air outward, and that outward flowing air is directed out the edges of the cover cascading along the length of the fins on the sides of the motor can.

Not a bad design.

Yes...it looks like it pushes air out around the edges and over the heatsink fins.

Sorry Mike...my misunderstanding. Yes...agreed...radial fans are better than a typical "PC fan" type.

And sorry for going overboard on the fan pictures.

 

[LightningRods]

Anyone who wants a big block with the factory fan left on just needs to ask for it. It won't fit on a bottom bracket drive as I said but you may have your own applications where there is room.

 

[ElectricGod]

Anyone who wants a big block with the factory fan left on just needs to ask for it. It won't fit on a bottom bracket drive as I said but you may have your own applications where there is room.

Until you posted pics, I don't think anyone knew it existed any other way than how you ship the motor.

 

[John Bozi]

Considering its a mid drive kit with plenty of airflow, and not buried behind something else - a fan seems pretty pointless.

I rarely get 10c over ambient.

[youtube]3xvuihZXfqk[/youtube]

 

[LightningRods]

My emphasis up until recently has been on bottom bracket drives where there is barely enough room for the big motor, let alone the cooling fan. The fan should be a nice accessory on your scooters, ElectricGod.

 

[atarijedi]

Considering its a mid drive kit with plenty of airflow, and not buried behind something else - a fan seems pretty pointless.

I rarely get 10c over ambient.

You need some sand tires!

 

[LightningRods]

Photos of the Madsen Cargo Bike with it's cargo tub and rack in place. With 2000 watts running through the gears, PAS and torque sensing pedal assist, this is a fun ride. I have a 3 way switch set up to allow three levels of power plus turn the pedal assist on and off.

 

[juanfeli]

I like it a lot. What happens when it rains?

 

[LightningRods]

You get wet.

I didn't have the cargo tub with the bike when I was working on it. I imagine that the tub has drain holes so that it doesn't turn into a mobile swimming pool.

 

[spinningmagnets]

When you install drain holes in the Madsen tub, make the type of hole that can have a plug inserted, so in the summer...you can have a mobile swimming pool!

Awesome work, Mike.

 

[LightningRods]

Thanks!

 

[ElectricGod]

When you install drain holes in the Madsen tub, make the type of hole that can have a plug inserted, so in the summer...you can have a mobile swimming pool!

Awesome work, Mike.

Exactly...that tub is big enough...minus the bump in the middle for the tire to bath in. What a great rain catcher!

 

[sparkz]

Add a little bit of hydraulics and you'll have a mid-drive dump truck!

 

[ElectricGod]

Add a little bit of hydraulics and you'll have a mid-drive dump truck!

I have a complete small hydraulic setup from a convertible car roof. It runs on a 12 volt motor. It would be perfect for this bike.

 

[John Bozi]

Looks like a bike you could rock up somewhere and throw surprise a party full with ice and beer.

Apart from heat handling, my favourite thing about the LightningRods mid drive kit is a 20 minute gear change. That's about how long it takes to

1. remove primary chain
2. remove motor sprocket
3. chain break out a link or add a new one
4. reverse steps 1 & 2

It's much easier than changing out any of the other spots. I will be changing the 13t back to 18t though once other parts arrive. Just needed to slow it down for a weekend ride with what I had.

Try this on your cargo bike
[youtube]OEOlf80DfYI[/youtube]
On this ride my hub motor mate lost 5 spokes.....