Surviving Without an Electrical System

June 2008

With contributions from Drew Fidoe

You don't really miss it until it's gone.

The Seattle area had a real bad windstorm in a rough December a year and a half back.  Despite living in the heart of the urban area, our power went out and stayed gone.

It was kinda fun, an adventure, on the first night.  I cooked up a huge batch of  thawing meat on the gas grill, we pulled a cozy couch up close to the gas fireplace, watched TV on a teeny-tiny "Watchman", and piled extra comforters on the bed.

But it got old...DARN old...after the second night.  The house had cooled to the low '50s, and it was getting boring sitting around all evening trying to read paperback books by flashlight wrapped up in layers of sweatshirts and blankets.  By the time power came back (about five days after the storm), we'd come to a new appreciation of how fundamental electricity was to our lives.

The same reaction can hit Fly Baby builders, too, when they contemplate installing an engine without a generator on their airplane.  The shock (so to speak...) hits them as they contemplate what they'll have to do without.  A starter, lights, transponder, maybe even a comm radio.

Why do it, then?

There are a couple of good reasons.  First, the lowest-cost Continental engines are A65s, most of which don't have provisions for starters and generators.   If you're looking for the cheapest way to get in the air, the no-generator A65 is the answer.

Second, the "overhead" involved with electrical systems on aircraft is tremendous.  You'll need a generator.  A battery.  Wires.  Fuses and fuse holders.  Switches.  Connectors, jacks, plugs, insulated wire holders, meters, etc., etc. etc.  Not only does it have to be installed and checked out, it's something that can go wrong over the years and have you tearing your hair out trying to fix.  When I look back to the problems my Fly Baby has presented me in twelve years of ownership, 90% of it has been related to the electrical system or avionics.  Plus, there's weight...a stock starter and generator plus a conventional battery probably weighs 40-50 pounds.  That's 5% of your gross weight!

Throw out the darn stuff, I say.  Install just what you're going to need, to support the kind of flying you plan to do.

Earlier this year, one builder was getting close to completion, and emailed me for some advice as to how much of an electrical system he needed.  I cc'd Stringbag's owner, Drew Fidoe, and together we came up with some advice.

Let's look at some aspects of the no-electrical-system world.

No Starter

If you won't have a starter, do one thing for me, first off:  Pile up a stack of bibles, Torahs, Korans, cases of Scotch Whiskey, bunny rabbits, or WHATever you consider holy, and please swear:  "I will never hand-prop my airplane unless it's tied to something so it can't get away."

People are afraid of being hit by the prop, but in ~25 years, I've only met one guy who has been injured by the prop when hand-propping.  But I've met a half-dozen or more that had their planes run away from them.

TailhookThe best solution for securing the airplane is a remote-release hook, like I describe in a separate article.  If you don't want to build one you can buy a glider hook from Wag-Aero; they're probably nearly $400 by now, but it gives you the advantage of a known quantity.

Carry a hank of rope and a good knife in the plane at all times.  Normally, if you stop somewhere, you can just grab a loose tiedown rope to loop through the hook.  Otherwise, you can cut off a bit of your rope to tie to a fencepost or something and leave it behind as you taxi away.

I flew N500F for seven years, in that time I only propped the plane once without having either someone in it or the tailhook secured.  Once was when the engine went to sleep on final when I was landing on a 15-degree day.  I coasted off onto the turnoff, then got out and flipped it to get it going again.  The second time was when I was in the middle of a big private field with no one around and
nothing available to tie do.

My normal practice at home was to tie the tail to the hook and put chocks on both wheels.  I'd start the engine, amble around and pull the chocks, then climb in, bolt myself onto the airplane, and reach down and pull the release handle.

Away from home, I just used the tail hook, but made sure the plane was POINTED somewhere safe, and made double-sure the throttle was at idle when I flipped the prop.  Especially after I didn't, and the engine started up at full throttle (the tailhook saved me).

Careful of folks who step up and offer to prop you; they PROBABLY have experience, but maybe not. 

Remember, though, that if they're pilots, you can put them in the cockpit to hold the brakes while YOU prop.  Tie down the plane normally, use the tailhook, do all the switch-flipping, etc. yourself, but have the guy in the cockpit to "guard the switches".  Show him the mags so he can cut them off if necessary.

When I've been at real weird out-of-the-way places, I've stationed non-pilots to stand by the cockpit with their sweaty hand on the mag switches and instructions on how to turn it off if things go bad.  Again, YOU'RE doing all the control and switch manipulation; they're just there for a backup.

Finally, on hand-propping, make sure you get a bit of instruction.  The big things are to watch your footing (you don't want to slip) and don't be TOO scared of the prop (if you're scared, you'll stand too far away and be leaning TOWARDS the prop).

Drew adds:

If the engine is going to be hand-propped, does it have at least one magneto with an impulse coupler?  If not, I recommend setting one mag around 5 - 10 degrees aft of top dead centre, and practice starting the engine on that retarded mag.  Starting the engine on a retarded magneto will greatly minimize propeller kick back and facilitate "first starts" after overhaul or reactivation.  Once some safe practice is complete, and any engine glitches attended to, set the mag for standard advance prior to flight.  I learned this one the hard way...

Comm Radio

Handheld radioLots of Fly Baby drivers, including myself, use handheld radios.  They work fine.  Rechargeable batteries tend to self-discharge on their own, though, so I kind of like the idea of using normal Alkalines.  Carry a spare set of batteries in the cockpit so you can get to them in-flight if you absolutely have to (See also the "Battery Only"discussion below).

Handheld radios put out a decent amount of transmit power, but their main limiting factor is usually that darned "rubber-duckie" antenna.  Most handheld antennas attach with a standard BNC connector, so you can install a "real" antenna on the airplane and hook it up to the radio.  With my setup, I hear planes in patterns ~60 miles away, and people say they can hear me just fine.

You can buy a commercial aircraft comm antenna for $50 or so, or you can try out my homebuilt antenna.

The ultimate solution for hand-held radios, of course, is what I did with my ICOM:  Installed it in the panel, power it from the aircraft power bus, and run a remote antenna.  See the separate article.  You operate it just like a regular aircraft radio.


First off, you have to determine whether the areas you want to fly in require a transponder.

In the US, you need a transponder to operate within Class A, B, or C airspace.  You do not need one to operate from the typical controlled field, which are located in Class D airspace (but, of course, if the field itself is in Class B or C, you'll need one...).

In addition, a transponder is required if you're going to operate within the 30 nm "Veil" around the airport at the center of a Class B airspace.  However, there's an important provision of the rule to be aware of.  The applicable reg is 14CFR 91.215 (b)(3):.  Here it is in context:

(b) All airspace.  Unless otherwise authorized or directed by ATC, no person may operate an aircraft in the airspace described in paragraphs (b)(1) through (b)(5) of this section, unless that aircraft is equipped with an operable coded radar beacon transponder...
(b)(2) All aircraft. In all airspace within30 nautical miles of an airport listed in appendix D, section 1 of this part from the surface upward to 10,000 feet MSL;
(b)(3) Notwithstanding paragraph (b)(2) of this section, any aircraft which was not originally certificated with an engine-driven electrical system or which has not subsequently been certified with such a system installed, balloon or glider may conduct operations in the airspace within 30 nautical miles of an airport listed in appendix D, section 1 of this part provided such operations are conducted—
(i) Outside any Class A, Class B, or Class C airspace area; and
(ii) Below the altitude of the ceiling of a Class B or Class C airspace area designated for an airport or 10,000 feet MSL, whichever is lower;

So:  In the US, you can operate within the 30 nm Class B Veil if your airplane does not have an "engine-driven electrical system."  What constitutes such a system?  The FAA has said the airplane must include all three of these items:
  1. A generator or alternator turned by the engine of the aircraft. and
  2. A regulator to condition the power generated by the alternator or generator, and
  3. A battery
Get rid of any of these three items, and you don't have to have a transponder for flying inside the Class B Veil (you DO still need a transponder to actually enter the Class B or C airspace, though).

wind generatorThe obvious thing to get rid of , here, is the generator and regulator and just operate on the battery alone...What engineers call a "Total Loss System."  Install just a battery and charge it up in your hangar or at home between flights.  My generator wasn't working right for over a year, and I managed just by slapping a charger on it when I put it in the hangar.  I have a starter, and had no problems with the five or six starts I did during a typical jaunt.

But....usually, some folks' eyes start lighting up, here.  "What about a wind generator!!!?"

It's absolutely true that a wind-driven generator does NOT qualify as an "Engine-driven electrical system."  If you have one, you don't need a transponder to operate within the Class B Veil.

While there have been certified aircraft that have used wind generators, they're pretty rare.  They produce a lot of drag, and they really don't generate that much power.  See Harry Fenton's take on them. 

Note that the above "loophole" for aircraft without engine-driven electrical systems only applies to flying in the US.  Drew Fidoe has this comment for his fellow Canadians:

If you are in Canada and flying in Class C airspace there is no waiver or grandfathering unless you are a glider.  No transponder no airspace.
I am flying out of one of the busiest airports in Canada, in an aircraft with no engine driven electrics.  Really, once I got my less than perfect wiring tweaked and remember to charge the battery (and turn off all switches after flying...check list check list :) flying battery only is a non-issue. 

Flying Battery-Only

If you don't have a starter, you really don't need that big of a battery.  Drew has a motorcycle battery stuck in his floorboards.  It's easy enough to put a trickle charger on them (if you've got a closed hangar) or to just pull it out and take it home.  If you do the latter, buy two and just keep one a'charging at home. Here's an article on Batteries and Fly Babies.

Drew adds:

Drew's BatteryI use the 12 amp-hour GEL cell in the photo.  Using a modern, Garmin transponder and an A-5 ICOM hand-held radio I seem to be good for about 4 to 5 hours of continual transponder and radio work.  The Transponder and radio both have low-voltage cut-outs, which is good for saving the GEL cell battery as they do not tolerate getting fully discharged.  I carry the standard ICOM radio battery as a back-up.  The ICOM is more sensitive to low voltage than the Transponder, and will normally shut off when transmitting indicating low power.  Then I have to either change batteries or shut the Tx off.  Since there is no engine driven electrical the "low power" indication always comes on the radio when I am transmitting, this isn't an issue, only when the low power indication stays on is when I'm going to have trouble.  This only happened a couple of time before I realized the "problem". 

I normally simply keep the battery on a "battery maintainer" or "smart charger" after every second or third flight.  I use a battery saver on the radio like Ron does, I used the fitted cigarette adapter but it was very unreliable and instead hardwired the battery saver directly to my electrical.

If you travel somewhere and intend to RON, don't forget to bring a charger for your radio and/or the battery in your airplane.  Drew adds:  For travelling away overnight (if I ever do this) I have a solar cell panel which I plan to leave in the sunlight, use transponder only when absolutely necessary, and if near and plugs will bring my charger with me.

Don't forget to install a fuse on the power line to the radio.  Don't use the plastic in-line fuse holders; these get brittle with age and break.  Auto parts stores sell holders for single-blade type fuses; I've got some of those and think they work well.

Drew's final comment:

Please use fuses and breakers, one friend nearly burned is Fly Baby and a new Microair Transponder in the process, when a wire was mistakenly shorted out!  I have breakers and fuses for the transponder, radio and other electrics.

Comments? Contact Ron Wanttaja .