# Anyone understand how to produce this wind-driven generator?

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#### spduffee

##### Well-Known Member
This idea is from 2001 and the person who made it (Mattias Jonsson) has not been seen on the Piper forum since 2010. I like the idea, but have no idea how to put it all together. Does anyone have any idea how to piece it together, or have a lead on an equally good DIY wind driven generator for aircraft use?

Thanks,

Shawn

#### JamesG

##### Well-Known Member
The article kinda spells out how to go about building one. If you want an OTS (off the shelf) one, I would look at some of the bicycle generator kits. They at least pass a nod to concerns over weight. But I'm not sure if they go up to a full 12V or not. Unless you are flying cross country, really a "total loss" system of just a battery is usually good enough for most day flyers. Its the simplest, lightest set up.

#### TFF

##### Well-Known Member
With the new LIPO4Fe batteries, the total loss systems are better. They charge very fast, very light, small. You can carry a wall wart charger and have it full charged from very low in less than an hour. Solar panel could be an option out where no power. A 4 lb battery can be 400 cc amps. Some of the aerobatic guys can get a weekend flying to a contest, the contest flying, and return home on one charge if the engine is an easy starter; starting Lycoming 0-360s.

#### FritzW

##### Well-Known Member
Log Member
Lot's of good u tube videos on how to do it. It looks like brushless model airplane motors are all the rage.

I tried an old bicycle generator with a model airplane prop and didn't have any luck. It could have been the diameter and pitch of the prop or my 50 cent garage sale generator was für Scheiße But my little Toyota pick-up couldn't go fast enough to spin the prop.

#### spduffee

##### Well-Known Member
There are two articles in that attachment. The second one explains more, but it's the first one I like, on the Cub. I have zero comprehension of aircraft electrical systems or any other for that matter. I can buy the R/C Pylon Brand Hi-Tork starter, but then what? That's my dilemma. How does it tie into the battery to recharge it? Where does the propellor mount to? See...zero.

Fritz - you were probably responding just as I was. If you have a Youtube example to share?

#### FritzW

##### Well-Known Member
Log Member

I'll be hanging out with the geek squad tomorrow. I'll see if they can sketch up some practical stuff. One of them probably knows the Mouser part numbers by heart

I'm guessing you saw the Gennipod and didn't like the price: GeniPod

Edit: I'd bet Wanttaja is the guy to talk to, you might shoot him a PM.

#### spduffee

##### Well-Known Member
Thanks Fritz! The BPE14 is more than twice the price of the GeniPod. There's got to be a better, less expensive way.

#### Wanttaja

##### Well-Known Member
Edit: I'd bet Wanttaja is the guy to talk to, you might shoot him a PM.
Oh, oh.

The Fly Baby group's engine guru, Harry Fenton, once did a writeup on wind generators:

" A couple of basic problems with wind driven alternators- drag and consistent voltage output through the airframe speed range. Typically, the alternator is tuned for max output when in cruise. However, when the airplane is at pattern speed, the alternator has no output as it is turning too slowly.

"Drag is an issue, too. The alternator has to be a pretty good size and the prop can provide a lot of drag. I had a torpedo shaped wind driven alternator on my old Stinson 105 and it cut the airspeed by 5mph and made a pretty loud whirring noise when it ran. "

Harry's solution...which I agree with, and an earlier poster also recommended... is just to run with just a battery and plug in a charger when the plane is parked. I flew most of one season with the generator of my Fly Baby inoperative. Wasn't a problem, even with my starter. I've got kind of an "APU" port on the belly of my airplane that makes charging the battery pretty simple.

Ron Wanttaja

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#### Dana

##### Super Moderator
Staff member
The article doesn't give much info because there isn't much to it. But neither of those articles are intended as a ful DYI; they're just a brief report on how somebody did it.

Forgive me if I'm being too basic: Any permanent magnet DC motor can be a generator. Connect it to a battery and the battery runs the motor. Force the motor to turn backwards, against the way the battery wants to spin it, and you have a generator, charging the battery. A diode or two, blocks the forward current from the battery so it doesn't spin like a fan on the ground, but the current still goes the other way to the battery. Stuff requiring power in the plane simply connects to the battery (presumably through a master switch and fuse(s).

The generator's output voltage is proportional to how fast you spin it, so you fiddle with the little prop to get it spinning at the right speed. You do this in flight, before connecting anything other than a voltmeter to the generator output! Too slow and it won't charge the battery; it has to be more than the battery voltage, but not too much. Too fast, too much voltage, and the magic smoke starts to leak out of the battery or your radios.

It's really best to run the generator output through a voltage regulator, though, to keep it consistent and avoid overcharging.

How the prop mounts to the motor depends on what the motor shaft looks like.

The one on a Cub, I'm surprised such a non TSO'd installation is allowed in Europe where the rules are so much more strict.

Dana

##### Well-Known Member
Harry's solution...which I agree with, and an earlier poster also recommended... is just to run with just a battery and plug in a charger when the plane is parked. I flew most of one season with the generator of my Fly Baby inoperative. Wasn't a problem, even with my starter. I've got kind of an "APU" port on the belly of my airplane that makes charging the battery pretty simple.

Ron Wanttaja

Ron Wanttaja
Solar panel. A 1x1 ft section will just be too little to power a basic plane during flight. With a battery, you never have to bother with charging again, it's light, simple and fool-proof.

#### Pops

##### Well-Known Member
Log Member
Oh, oh.

The Fly Baby group's engine guru, Harry Fenton, once did a writeup on wind generators:

" A couple of basic problems with wind driven alternators- drag and consistent voltage output through the airframe speed range. Typically, the alternator is tuned for max output when in cruise. However, when the airplane is at pattern speed, the alternator has no output as it is turning too slowly.

"Drag is an issue, too. The alternator has to be a pretty good size and the prop can provide a lot of drag. I had a torpedo shaped wind driven alternator on my old Stinson 105 and it cut the airspeed by 5mph and made a pretty loud whirring noise when it ran. "

Harry's solution...which I agree with, and an earlier poster also recommended... is just to run with just a battery and plug in a charger when the plane is parked. I flew most of one season with the generator of my Fly Baby inoperative. Wasn't a problem, even with my starter. I've got kind of an "APU" port on the belly of my airplane that makes charging the battery pretty simple.

Ron Wanttaja

Ron Wanttaja

#### Dana

##### Super Moderator
Staff member
I can't speak for the original poster, but I've thought of building a wind generator too. The idea is to power a handheld radio and perhaps a GPS without having to worry about charging the batteries before flying or whether they'll run out on an extended trip.

On some aircraft (mine is one of them) there's no practical way to mount an alternator, and not having an engine driven electrical system can be an advantage... it exempts you (at least in the US) from some requirements like the Mode C veil, or the coming ADS-B requirement.

Dana

#### cluttonfred

##### Well-Known Member
HBA Supporter
+1 on the idea of a total-loss battery system charged on the ground with a "smart" charger that can be left plugged in without damaging the battery. It's also not hard to carry a small, AC-DC 12v trickle charger and/or a roll-up flexible panel for cross-country flights. I posted these comments in a similar thread on the Eagler's Nest forum asking about wind generators, but I actually now think a total-loss system makes more sense.

While it gives old-time A&Ps the heebie jeebies, a stock Bosch 009 distributor and coil powered by a motorcycle battery in a total loss setup (recharging on the ground only) is about as simple as it gets. An optional wind-driven generator can keep that battery charged if you don't mind the drag and noise associated with the little turbine. When I asked Steve Bennett of Great Plains for his recommendation on a minimalist VW installation for the Clutton FRED, that's what he recommended (see Clutton FRED - Steve Bennett on FRED VW power and GeniPod).

One thing to keep in mind if going with any total loss or limited charging capacity system is that most of the lower maintenance, more powerful spark distributorless electronic ignitions draw much more current than a stock distributor and coil. The GM HEI-based Davis Unified Ignition (DUI) popular in off-road and racing applications (see VW Type 1 DUI Distributor - Street/Strip Version - Performance Distributors Performance Distributors) is an interesting option, with an integral coil for easy installation and low current draw, though it's not exactly aerodynamic next to anything but a Vertex magneto.

Total loss or limited charging capacity also means you need to place little or no other electrical load on the system, since every additional amp of current draw is going to require upping the capacity of your battery. For long battery life, you'll need to keep the total power used in amp-hours to less than half of the total battery capacity (exact fraction depends on the battery type and specs).

#### Vipor_GG

##### Well-Known Member
\$300 gets you a GenniPod and you have something ready to install.

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