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2.6 lb, 30 amp Monkworkz Generator Intro Videos

monkworkz

Member
Advertiser
Greetings,

I made a couple of videos talking about the 2.6 lb, 30 amp vac pad generator I developed and have been selling:

Introduction
Bench Demo

I'll be working up an installation video as well.

Hopefully this better illuminates why I developed it, what it does and how it works.

Hit me up if you have any questions.

They are available now, $995 plus shipping. Email me at [email protected] if you're interested.

Thanks!
 
Bill, very well presented. I'm a future customer for sure when the time comes to swap out the old mags for electronic ignition and the panel upgrade! Welcome advance for us EAB folks.
 
Quick Observations

Can you compare it to the 40 amp B&C and what the advantages might be over that option?

There's no single perfect application for such or the industry would have settled on it a long time ago. Quick technical observations keeping in mind I'm ME not EE. These could very well be incorrect.

Pros
- weight
- no excitation
- relative size

Cons
- Requires blast cooling; one each dyno and control module.
- Parasitic load. PMs versus excitation will have a permanent load from engine acc drive versus an alt
- Cost (slight)

Unknowns/Debatables/etc.
- details on the moving case/device would be beneficial, Assuming part of outer case spins?
- Digital Control module versus dumb solid state stuff
- Installs that could take advantage of size (engine to FW) are (broadly generally) the ones that can least afford engine cooling air drains.

I'm sure there's more. My biggest curiosity are the parasitic loads. Hopefully the OEM reads and replies. Having options benefits some of us directly and all of us indirectly.
 
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Hi Bill what type of moisture protection does the generator and regulator have?

Thanks
Bill D
 
More details

Thanks for the replies.

Parasitic load:
I think this is in the noise.
When there is no load on these generators they basically present very little resistance, so with no electrical load almost no parasitic load. You can easily spin the generator by hand and it will coast for a couple of rotations. There is minimal "cogging" where the rotor feels like it gets stuck in ruts made by the permanent magnets.

As an aside, the orange generators to have substantial cogging, like will lurch forward forcibly in your hand, but I suspect that overall they have very little parasitic load as well when you average the torque for a full rotation. The magnetic field has to be pushed through but then also gives a push, and averages out to ~0. The orange generator is like pushing a car up and down hills, the monkworkz generator is like pushing a car on a flat road, both averaging out to around the same energy for distances that include many climbs and descents and have zero net elevation gain.)

However if you short the leads together it feels like you're churning ice cream, still very smooth, and the faster you try to spin it the more resistance it presents. But with no load there is very little mechanical resistance.

I have measured the mechanical to electrical efficiency and it's 90-95% in some case better than that, then the electrical efficiency of the regulator is substantially better still.

Alternators require the magnetic field to be actively generated and in rough numbers that's probably about a 10% efficiency hit, i.e. you need to put in around 1 amp of field to get 10 amps of current out. That will be less at higher RPM. Not something I have measured but that is generically how that works.

I would expect the Monkworkz device to be superior in mechanical to electrical efficiency at all RPM because it doesn't have to generate the magnetic field.

Anyway, parasitic loss is close to zero. If there is no load there is very little drag torque presented to the drive.

When it is actually making power there is loss in the conversion from mechanical to electrical power. Here is a quick worst case estimate of what the loss would be:

amps * volts = power
30 amps * 14.4 V = 432 watts <- call this power made good, why you bought the device

Power out /(regulator efficiency*Generator efficiency) = mechanical power required
432/(0.95*0.9) = 505 watts <- overall mechanical power harvested from your engine

lost power = 505-432 = 73 watts or ~0.1 HP. <- power you want to minimize

73 watts is high because the regulator efficiency is actually quite a bit better than 95%.

So even worst case scenario, the parasitic load is 0.1 HP, or less than 0.1% of the power output of most lycomings. Even if the alternator was a lot worse the parasitic load would still be in the noise(to me anyway).

But yes, whatever power is lost does need to be taken away with cooling and that is why there are blast tubes. The blast tubes are constrained to put the air directly where it is needed and nowhere else. I've measured the impact on cowling pressure differential with and without and it's less than the difference of 1 knot of airspeed.

Comparisons to other alternators:
I'm not an expert on other products, one tester, Dave Anders(with a very fast RV-4), claims that with a vac pad alternator he was not able to taxi and get a positive charge, he needed around 1400 (crank) RPM to show a positive charge, with the Monkworkz generator he gets away with ~1000 RPM. 1400 RPM is too much to taxi with and overspeeds his taxi or overheats his brakes.

Moisture protection:
The circuit board has a conformal coating baked on for moisture protection and lives in a machined 6061 box, the generator has sealant around the wire transitions. The construction isn't any different from other motors on your plane like in the starter or the alternator for that matter.


Thanks,

Bill
 
I can't add to the tech discussion but I'm very impressed with your manner in both the videos and on VAF. Direct answers to questions where you have them, best guess answers when appropriate that are labelled as such, and good "facts only" videos where you compare to other manufacturers parts without beating on them all paints a great picture.
Clearly you know your subject well and you deserve to have your product do well.
 
I’ve been flying the Monkworkz generator on the back of the engine on my RV-8 for a couple of months now, and it has been flawless. With LED lighting, EFIS, modern radios….30 Amps is generally plenty, and I have done about half my flights with the Monkworkz only turned on, and the ND turned off.

I’ve got a full review coming in the July 2022 issue of Kitplanes….

Paul
 
Really excellent concept!!

I approached the alternator guys at OSH 15 yrs ago and asked if they were working on some smaller, lighter, more efficient, and longer life machines. SR, IPM, SPM something . . .Whaaat?? :eek:

For 95% efficient devices, why does it need two 3/4" hoses to keep cool? Are the windings rated for 130C? That seems like a lot of air, what is the assumed delta-P pressure for adequate cooling? I understand magnet temp requirement, but the rotating shell should provide the cooling there.

Is the "regulator" actually an AC-DC inverter to achieve the efficiency?

Claw pole alternators are only 55-60% efficient, higher amps and some don't need extra cooling.

I know heat has to go somewhere or temps just keep rising, but the cooling just seems a little high for an efficient SPM generator.

Are you going to be working toward a replacement for the short lived primary alternators?
 
Thanks for the Replies!

Thanks for the kind words everyone, I think that this is a great product and that others can benefit from it.

For 95% efficient devices, why does it need two 3/4" hoses to keep cool? Are the windings rated for 130C? That seems like a lot of air, what is the assumed delta-P pressure for adequate cooling? I understand magnet temp requirement, but the rotating shell should provide the cooling there.

Is the "regulator" actually an AC-DC inverter to achieve the efficiency?

Claw pole alternators are only 55-60% efficient, higher amps and some don't need extra cooling.


I know heat has to go somewhere or temps just keep rising, but the cooling just seems a little high for an efficient SPM generator.

The device is quite a bit smaller, so the heat gets concentrated in a smaller volume and temps can get out of control easier and faster.

I can say plenty more but I don't like to share details that would give a would be competitor an easier time reverse engineering my work. I did file for a patent but that's only part of the work I have done. Saying X is the temperature limit lets someone else select materials and I spent 5 years getting this far. If you want high reliability then you need the cooling, same story for any other alternator, the ones failing early tend to be the ones that don't have cooling. If you want it to last you should put the cooling on it, if you're CHTs are well behaved then there should be sufficient cooling for the generator and regulator. Any other use and I can't comment on how well it will perform. Dave Anders tested on a 115F day in Phoenix, including a heat soak after shutdown. It stayed within limits the entire time with the cooling ducts added.

Are you going to be working toward a replacement for the short lived primary alternators?

For some people this is a replacement, for others maybe not, I know it supports all my electrical needs other than redundancy. I'm working something that will run off the belt but it's barely a concept right now.
 
RE: Monkworkz generator

I have been flying for several months (about 40 hours now) with the Monkworkz MZ-30L as my primary alternator/generator. When my PlanePower alternator bit the dust at 420 hours, I decided to the give
the Monkworkz MZ-30L a try. It has performed flawlessly. At around 1100 RPM or slightly higher it is producing 14.3 to 14.4VDC and it supplies more than adequate current. When I have everything but pitot heat turned on, my aircraft is using around 16 amps, so the MZ-30L is more that adequate for my VFR flying. The one additonal cooling blast tube need for the MZ-30L controller has been a non issue other than the need to drill a hole in the baffles and install the blast tube. I have not noted any change at all in my engine cooling. I installed the controller on the firewall but it is small enough that it can easily be installed using Adel clamps on the motor mount which I have seen in pictures of other installs which keeps the cooling air blast tube short.

When I wired my aircraft initially, I didn't plan for having a backup alternator and to implement a BU alternator after the fact would not be easy. The MZ-30L should make this possible with minimal headaches, as it can be configured to operate as a backup to the primary alternator in a dual alternator installation. No cockpit switches or external diodes to power separate busses etc. or pilot actions are necessary. The smarts are in the MZ-30L controller unit and it brings the MZ-30L online when the primary bus voltage falls below a specific level.

Recently, on a Sunday morning after my aircraft had set for about 3 weeks, I thought I had a problem with the MZ-30L because the system bus voltage was lower than usual after engine startup and was taking a while to get up to normal. I shut down and called Bill and left a message to try and get advice on how to trouble shoot the MZ-30L. I was really surprised that he called my back within an hour, gave me some good points on things to check. Turned out to be my battery was just discharged lower than normal and it was just taking longer that usual for the battery to get charged up after the start. Bottom line, you can expect superior product support from Bill at Monkworkz.
 
For some people this is a replacement, for others maybe not, I know it supports all my electrical needs other than redundancy. I'm working something that will run off the belt but it's barely a concept right now.

At the rate I'm building my RV8, perhaps I'll have primary and secondary electrical generation from Monkworks ;)
 
Another hearty endorsement. I have a unit in a RV-10 used solely as a backup. I originally designed my system without a backup alternator. When this unit came along it was a no-brainer to add it. It solved all my concerns with other vacume pad driven units (large-heavy-remote controller-low output).

It was a breeze to install. No current limiter required (built in), no amperage output device required (built in). The cooling blast tubes made absolutely no difference in CHT's. Can handle my fully loaded panel plus other loads (external lights, boost pump, etc).
 

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Bill,

Watched your videos. Awesome product! It makes a lot more sense than what has been on the market so far. A lot lighter, smaller, more sophisticated tech, and cheaper too.
I have a question.
If charging a lithium battery, when the engine comes on the battery draws max power available from the alternator/generator. Only temporarily, but that just depends how depleted the battery is.
Since there's not a whole lot of airflow coming in yet, what happens to the generator/regulator temps? Does your regulator limit the delivered current when the temps go up, to protect itself?

Lenny
 
Bill,

Does your regulator limit the delivered current when the temps go up, to protect itself?

Lenny

Thanks for the kind words Lenny.

Yes the device does self-protect but those limits are meant to be more like guard rails, if the cooling ducts aren't installed, landing on Venus, that sort of thing, but in normal ops they shouldn't kick in.

Thanks,

Bill
 
Congratulations and good luck in your business!

Thanks for the replies, Bill. Understandable to protect the key design parameters I have had a few ideas swiped that others patented too, but product development is a costly investment worthy of protection.

I can probably guess at most but the concept and execution is apparently well done and meets some of the higher customer "wants". Great as a durable/reliable primary power source, and even better as a backup which has to be much more durable than the primaries we have today.

It will be on my list for the next generation system in my -7. This device is a real step up from backup batteries and power devices. Some battery systems are good, but most are not confidence inspiring. Distributed backup batteries for each device are not practical from the big picture and not equal in specifications. Following some field hours proving reliability, it could mark a fundamental change in the design of experimental systems. We just need a thousand new installations!!

It is really really difficult to make a competitive device for a low volume market, congratulations and good luck in the growing the business. A fair price for something more reliable/durable than the engine (or maybe 2-3 engines).
 
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We added the B&C 40 amp to our Rocket and deleted the normal belt driven alternator. So far it has been perfect. Eliminating the heavy conventional alternator seemed like a no brainer. I know several others who have gone with a pad mount as their only alternator and had similar success. Had I known about this product I probably would have used it instead of the B&C. If I have a issue with the B&C this will probably be the replacement. With modern lighting and avionics many RV’s are carrying extra weight producing amps they simply don’t need.
If you want a nice weight reduction and better lighting this product along with modern lights is a great modification.
G
 
I just ordered one to replace my B&C backup unit, main reason was to get 3-4 extra pounds off the nose. Looks like a good unit and Bill has done his homework. I also wanted something I could confidently offer my panel customers as a backup and the only way for me to gain that confidence is to actually install and use it myself.

As far as the Earth X question, that battery is going to demand a lot from any alternator, most alternators are not really designed to operate at max output for very long.
 
I installed this generator as a standby generator during my Condition Inspection. I finally got a chance to test it today and it was flawless (primary alternator is a 60amp B&C).

The Dogwood (VA42) runway repave process started today so it will be ~3 weeks before flight testing. Some thoughts for now:
- The unit works as advertised.
- The install instructions are well done.
- The extra functions incorporated in the regulator unit sets a new standard for how to do things right.
- On install I strongly recommend making the connection to your EMS to have an indication come on when the generator is carrying the load (or a simple LED can be used). Turning off the primary alternator the transition to this generator picking up the load was seamless, so much so that without the indication you would not know the primary alternator failed.

Carl
 
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Direct Connection to the Battery Not Recommended

Thanks for the comments Carl!

Somewhere I thought I saw a question about connecting the generator directly to the battery, this isn't recommended, there is a resistive voltage divider on the output that keeps tabs on the output voltage and that will over time drag your battery down, bottom line: you need to connect it on the switched side of your master relay/contactor.

Bill
 
Hi Bill,

Question… does it work well if the battery becomes disconnected?
.

No issues, but you'd be 100% limited to the current limit, subject to RPM, so if you had a load that went over the current limit the voltage would reduce until the current limit was managed. If there is a battery attached, even a small one like a PowerSonic PS-1220 then it would carry the bus through period of higher draw. If the loads are all steady state the battery doesn't do much but if there are pulsed loads like strobes then the battery can smooth out those peaks and a valleys.
 
Good videos, Bill. I really enjoyed the sparks! I think you have raised the bar in terms of abusing your product to show it can handle it.
 
Gear Driven Alt

Watched the videos - great job. I have the B&C 30 amp gear driven alt as a backup so can make a comparison based on what appears in the videos. Got to thinking about the decision making process I went though before buying the B &C model. Looked at the legacy and technology of the alternator - converted automotive, industrial, farm application versus new clean sheet design. Design of casing and shear pin,gooseneck for protection against parts coming off the internal winding,magnet assembly and ripping the accessory case apart. Remembering the experience of having an impulse magneto fail in cruise flight,rip the accessory case apart and cut through an oil line. Thats a story for another day. The takeaway message is that the design and validation of the gooseneck/ shearpin arrangement is very important given the energy involved in the rotating machinery. What level of testing needs to be done given the cyclic load nature of the drive source. The endurance test procedures and test setup needs to represent typical electrical loads in addition to RPM, temperature and vibration if a realistic assessment of life and performance is to be made. Anything other than a reciprocating engine drive is not representative. I dont know that this work has been done with the B& C or any other gear driven alternator but it is a question to ask. Turning to the regulator one could ask many similar questions about modified legacy unit or new clean sheet design, engineering testing and qualification,endurance testing.
Given the 3 phase axial alternator and the likely regulation and control technology used only small improvements in efficiency are likely so I would be surprised if the cooling and power requirements are substantially different than the existing products available. Conceiving,designing,developing,manufacturing,testing and bringing to market a successful complex avionix product with a very small team and limited funding is a very challenging task if it is to be done in a robust high integrity manner. I understand the need to protect the intellectual investment but there needs to be an equal level of marketing focus on the level of product integrity beyond the weight and electronic fault protect features. The devil is always in the details so I would want to see some of the details to be sure I was not (unknowingly) part of the product development team before buying this product.

KT
 
@Carl Froelich - Since this device is suggested to be installed on the switched side of the master, can you share how you approached this in duplex architecture world? Dioded to each vital bus like before?


@ Monkworkz - Reference above. I have a similar mechanical concern. A "conventional" design offers some protection again FOD'ing the back side of your engine space in the event the rotating mass has a Rapid Unscheduled Disassembly. I can't quantify this, of course. As your rotor/stator configuration is a bit unconventional with a spinning case (and winding, I assume), any comforting words from the OEM here would be very helpful, IMO.

I assume this was to keep overall weight down by not having the mechanical robustness for spinning heavy PMs?

A reply to the first part would be helpful to all. I'm not too hopeful the second will be addressed and that's understandable.
 
@ Monkworkz - Reference above. I have a similar mechanical concern. A "conventional" design offers some protection again FOD'ing the back side of your engine space in the event the rotating mass has a Rapid Unscheduled Disassembly. I can't quantify this, of course. As your rotor/stator configuration is a bit unconventional with a spinning case (and winding, I assume), any comforting words from the OEM here would be very helpful, IMO.

I assume this was to keep overall weight down by not having the mechanical robustness for spinning heavy PMs?

A reply to the first part would be helpful to all. I'm not too hopeful the second will be addressed and that's understandable.

This alt just like other BU alternators connects via the vacuum pad drive which is standard on Lycoming.
If the alt seizes for example (worst case) the shear coupling disconnects is all, there are no parts inside the case like a magneto.
 
This style of motor has made the electric vehicle market possible because of the huge amount of power they produce for their small size and weight. These motors are called outrunner motors and I first saw them 20 plus years ago in RC planes and helicopters. All drones, e-bikes, e-skateboards, onewheels and any other electric vehicle use these incredible, efficient motors. There are probably millions of them produced every year in all shapes and sizes? When I saw the outrunner being used as an aircraft generator, I thought it was a brilliant idea because of its' compact size, light weight and simplicity! Kudos to Bill for making this work and I hope you do well!!!

Phil
 
Dynamic Disassembly

Greetings,

Dynamic Disassembly, We really hope this doesn't happen obviously!

The generator has been on a 10:1 compression IO-360 for 300 hrs, no issues with the generator coming apart. I did have to beef up a few things on the regulator side of things but the generator has been fine. 360s have a well deserved reputation for severe vibration issues and the compression makes it worse. On a 360 the crank to prop interface goes from something like +2000 ft lbs torque to -1500 ft lbs every rotation as it goes from compression to power stroke. (and average of ~500 ft lbs puts you in the neighborhood of the expected power output) 6 Cylinder engines don't have that nasty trait and should be less of an issue.

I have been asked questions about vibration surveys and that sort of thing is typically going to be confined to a particular engine/prop configuration. The spec I have heard for the mag holes is 40 Gs. I did a pull out test on the mounting screws for the generator and what I saw was good for 80 Gs, and I didn't test the screws to breaking strength, just up to what would amount to 80 Gs pulling on the generator.

The design strategy here is to make it really beefy so that it can put up with the wide variety of situations that might be found on experimental aircraft but still try to keep it light weight.

The generator is an "outrunner" where the magnets on the outside rotate, the windings stay put on the inside. There are no brushes. There is a shear coupling that will also break if the generator seizes, since the redesign I haven't had any break.

I hope that helps!

Bill
 
@Carl Froelich - Since this device is suggested to be installed on the switched side of the master, can you share how you approached this in duplex architecture world? Dioded to each vital bus like before?
SNIP

The short answer is no. Rethinking how I did diode isolation to the two avionics busses on my old standby alternator scheme I decided that was overkill - as in I was mitigating a risk of one high probability failure (the primary alternator) as well as a couple of simultaneous low probability buss problems.

I wired this as a backup generator, output going to the same firewall mounted starter solenoid battery lug as the primary alternator. In other words in the role it mitigates just the one risk, loss of the primary alternator. The dual battery, separate buss scheme remains in place to mitigate the other common single point failure risks.

Carl
 
Walt,
The point about the comparison between an impulse magneto and a permanent magnet alternator is that there is a lot of energy to dissipate in both if the rotating parts suddenly stop rotating - the most likely casualty is the engine accessory casing whether or not the shear pin fails. In my experience the shear pin and the gooseneck failed but it didnt stop the magneto from launching itself halfway through the cowling still attached to a large piece of the accessory case and taking the oil cooler oil line out on the way. The shear pin and gooseneck are there to protect the engine gears. The endurance life test on the alternator is there to confirm that the risk of a catastrophic failure is within acceptable levels and the destructive failure test is to confirm the unit does turn into a grenade when it fails. If this work has not been done then you are relying on wishful thinking and the experience of units in the field - how much of a test pilot do you want to be?

KT
 
This alt just like other BU alternators connects via the vacuum pad drive which is standard on Lycoming.
If the alt seizes for example (worst case) the shear coupling disconnects is all, there are no parts inside the case like a magneto.
Hey Walt. I wasn't clear, I guess. I am specifically talking about the rotating mass of the device external to the engine. If I'm understanding the MWz literature correctly, the case spins. As mentioned, I assume the field windings are spinning with the case and the traditional rotor components are stationary. Again, I assume power/weight was a driving design consideration for this approach. The coupling's primary function is protection of the driving equipment (acc drive here) which would come from exceeding torque limit of the coupling material. A manufacturing defect, other damage, etc. to the seemingly unrestrained rotating case could produce FOD before a resulting imbalance, counter-torque, etc could shear the coupling. True in more conventional designs as well but that rotating mass is inside of the fixed stator case. The overall weight of the device is a two edged sword; lower rotational inertia/energy versus mechanical robustness. That said, this mechanical failure mode mitigation may be deigned in. If I'm still wrong, someone will correct me. That's what VAFers do. Still would like some words here from the OEM regarding such; would hopefully be beneficial.

Edit = A few replies before I hit "send" here, obviously. Thanks to all. It helps.
 
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Greetings,

Dynamic Disassembly, We really hope this doesn't happen obviously!

The generator has been on a 10:1 compression IO-360 for 300 hrs, no issues with the generator coming apart. I did have to beef up a few things on the regulator side of things but the generator has been fine. 360s have a well deserved reputation for severe vibration issues and the compression makes it worse. On a 360 the crank to prop interface goes from something like +2000 ft lbs torque to -1500 ft lbs every rotation as it goes from compression to power stroke. (and average of ~500 ft lbs puts you in the neighborhood of the expected power output) 6 Cylinder engines don't have that nasty trait and should be less of an issue.

I have been asked questions about vibration surveys and that sort of thing is typically going to be confined to a particular engine/prop configuration. The spec I have heard for the mag holes is 40 Gs. I did a pull out test on the mounting screws for the generator and what I saw was good for 80 Gs, and I didn't test the screws to breaking strength, just up to what would amount to 80 Gs pulling on the generator.

The design strategy here is to make it really beefy so that it can put up with the wide variety of situations that might be found on experimental aircraft but still try to keep it light weight.

The generator is an "outrunner" where the magnets on the outside rotate, the windings stay put on the inside. There are no brushes. There is a shear coupling that will also break if the generator seizes, since the redesign I haven't had any break.

I hope that helps!

Bill
A couple of questions -
1. do you plan on doing any catastrophic failure testing?
2. Do you have a plan for endurance testing of a number of units for a representative lifetime - say 1000 hrs of running in 50 hour steps to assess performance ,maintenance and failure modes?
300 hrs is a good start but it needs to be substantially more in the final configuration. Seems like you are still in the middle of development but advertising a largely untested product.
Your point about the cyclic nature of the torque is well taken. Additionally the reflected inertia of the rotating mass is increased by the square of the gear ratio so building a test stand with an automotive 4 banger and a different gear ratio can get you to an equivalent representative test condition.

The thought of a 1 kg weight spinning at 3000 RPM coming loose just in front of the firewall might encourage me to take up golf.
I really want to see your test plans for product integrity ( and the results) before give any consideration to this product.

KT
 
Scott,

This design’s operation is the similar to the B&C 8 amp generator (as in the outer case spins), and is part of the rare earth permanent magnet scheme. I’ve seen one of these B&C generators fail, and the shear coupling did it’s job. I would expect nothing different here. If your concern is somehow this generator could disintegrate and put FOD into your engine case, I suggest this is not a realistic outcome. If your concern is the generator case will fail and it departs from the engine, then I guess there is some low probability of that happening. I’m thinking however the outcome, as in potential damage to the engine, is low.

Could the case fracture? Yes - just like other options. I know of a B&C 30 amp vacuum pad unit on a Continental with a cracked case. Same could happen to your belt driven alternator and I’ve seen more than one cracked belt driven alternator mount.

I suggest the advantage on this unit is the low mass. I assume this would reduce the momentum associated with fatigue failure.

Carl
 
Scott,

I suggest the advantage on this unit is the low mass. I assume this would reduce the momentum associated with fatigue failure.

Carl

Exactly, the rotating mass is around 11 oz, or 320 grams, take away the shaft and its 9.5 or 270 grams oz a lot less than other rotors. Substantially less than 1 kg.

The rotor sits very close to the stator(another way to get good performance) and my expectation is that the primary wear out mode will be for the bearings to wear out and the rotor to inertia weld itself to the stator breaking the shear coupling.

You have to pull really hard to get the rotor to come off the stator, the magnets want to stick to the stator, so the rotor pinballing around between your FW and engine is pretty unlikely.

Bill
 
Exactly, the rotating mass is around 11 oz, or 320 grams, take away the shaft and its 9.5 or 270 grams oz a lot less than other rotors. Substantially less than 1 kg.

The rotor sits very close to the stator(another way to get good performance) and my expectation is that the primary wear out mode will be for the bearings to wear out and the rotor to inertia weld itself to the stator breaking the shear coupling.

You have to pull really hard to get the rotor to come off the stator, the magnets want to stick to the stator, so the rotor pinballing around between your FW and engine is pretty unlikely.

Bill
Even so - 320 grams spinning at 3000 RPM that gets loose can be quite spectacular.

KT
 
The rotor sits very close to the stator(another way to get good performance) and my expectation is that the primary wear out mode will be for the bearings to wear out and the rotor to inertia weld itself to the stator breaking the shear coupling.


Bill

So what is your expectation on bearing/unit TBO?
I also didn’t see any info on warranty in the manual or on the website.
As an early adopter I want to know that you’re going to stand behind your product.
 
Warranty

Hi Walt,

You are correct, I don't have a warranty posted on the website but I'm happy to match the industry standard of 200 hrs/2 years.

I think I can do much better, ideally 2000 hrs MTBF, and to get there I really do want to know about any failures to try to make improvements.

With thermal and short circuit protection I think I've made it difficult to break from a bad installation perspective, so I don't expect warranty claims from that. If you don't cool it, its just not going to make power on hot days, and you saw the video, you can short it all day long and it doesn't care. The device only has one moving part, no brushes, and it spins much slower than a belt driven alternator. The bearings are rated for 45,000 RPM, and rotor is balanced. The electronics package should be able to do 2000 hrs as well. All of that should mean long life span.

Its worth mentioning that actually racking up 1000 or 2000 hrs of time is a tall order.

For most pilots even 100 hrs a year is a lot, so 1000 or 2000 hrs is 10 or 20 years at a minimum.

The high compression RV-4, IO-360 I mentioned that has 300 hrs on it, that has all been since the Dec of 2020 which is remarkable.

Getting a track record is going to take time, I'm grateful to anyone willing to try something new and won't leave you hanging if yours breaks.

Progress has to start somewhere and I completely understand that risk tolerance is going to vary, the EXPERIMENTAL we sport in 2 inch letters is not ornamental.

There are benefits, we've been riding around with glass panels, electronic ignition and autopilots for literally decades and you'd be hard pressed to find a certified plane with all three of those, but those benefits also mean that sometimes the electronic ignition didn't get to 2000 hrs, or back to the airport.

Bill
 
Speaking of durability, one thing you ought to consider is adding a locating boss to pick up the 1.5" dia hole in the vacuum pump drive like every other manufacturer does that makes accessories to fit that pad. Just relying on the 1/4" threaded studs to axially locate your unit can lead to premature fatigue failure and spline wear if the unit is not mounted exactly on the same axis as the female spline drive in the engine-mounted adapter. Please read this as constructive criticism; I'd really like to see you succeed!

In the attached pics, note how only your MZ-30L is missing the locating boss.

unnamed.jpg Plane-Power-FS-Series-800px.jpg

07-06771-2015.jpg tempest-overhauled.jpg
 
Engagement Mount

Hi,

Engaging the ID of the vac pad is certainly better.

I have a mount in the works that engages the vac pad just as you suggest, I've notified customers and offered an upgrade. Any future shipments will include this.

Bill
 
We added the B&C 40 amp to our Rocket and deleted the normal belt driven alternator. So far it has been perfect. Eliminating the heavy conventional alternator seemed like a no brainer. I know several others who have gone with a pad mount as their only alternator and had similar success. Had I known about this product I probably would have used it instead of the B&C. If I have a issue with the B&C this will probably be the replacement. With modern lighting and avionics many RV’s are carrying extra weight producing amps they simply don’t need.
If you want a nice weight reduction and better lighting this product along with modern lights is a great modification.
G

I did the same thing - went to a pad mount for my day vfr RV8. No regrets at all.

Bill, this looks really nice! At what RPM will this start generating power? The B&C pad mount pics up around 900-1000 rpm. How does yours compare?
 
I did the same thing - went to a pad mount for my day vfr RV8. No regrets at all.

Bill, this looks really nice! At what RPM will this start generating power? The B&C pad mount pics up around 900-1000 rpm. How does yours compare?

You'll get 15 amps at around 1000 RPM, over 1800 you get 30 amps.

Bill
 
Hi Bill,

Question, does the generator run at the RPM of the coupling or is there a gearbox inside to increase RPM. A question from the Aeroelectric List.
.
 
Direct Drive

Yep, it's direct drive, the only thing between the generator shaft and the vacuum spline gear is a shear coupling.

Bill
 
Hey Bill,

Is there any plan to make a belt drive version of this? I currently run a B&C dynamo on my vacuum pad and it's been trouble free for 900 hours.

The 60 amp alternator hanging on the front from the folks that buy the cheap version of the ND alternator and make it "aviation grade" I'd LOVE to replace with a better mouse trap! (and I actually do not need 60 amps...) The thing has an intermittent habit of tripping the field circuit that is annoying. It'll go for months just fine, then it'll trip a dozen times within a couple flight hours.

As I'm heading for an instrument rating I'll need to do something with that problem being an all electric airplane and all.
 
Belt Drive

Hey Bill,

Is there any plan to make a belt drive version of this?

Hi Jesse,

Yes, I am working on a belt driven version. There are some mechanical hurdles so don't expect anything for quite some time but it is my intention to make one that runs on the front of the engine.

Thanks,

Bill
 
Hi Jesse,

Yes, I am working on a belt driven version. There are some mechanical hurdles so don't expect anything for quite some time but it is my intention to make one that runs on the front of the engine.

Thanks,

Bill

Great! I'll watch for it! And when you get the lightweight aluminum brackets made, get them anodized red! Gotta look cool!
 
Install was easy, getting the larger B&C off required removing the mag for access. So far I like what I see and think it will be a winner. I was surprised how quickly it picked up the load compared to the B&C I removed. Much more compact and weight loss of about 3-4 lbs..
Voltage setting for stby use is perfect at 14.2

2022051917320434--6330272223018710539-IMG_1811-X3.jpg


Added pic below for a little more reg install detail.
Used a 2 conductor shielded wire for the enable switch as suggested in the IM.

2022051917320434--5859541214576692589-IMG_1812-X2.jpg
 
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Walt, is that just a double Adel Clamp on the engine mount for the electronics? I do like that if so.
 
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