Hints

MARCEE Minnesota Area R/C Electric Flight Enthusiasts

Here are some hints for a "successful" start into Electric flying. They
are things that I have run into during over 20 years of silent flight.
Use them as starting points in your new adventure. Remember, these
are just my opinions. Ron Fikes, Palo Alto, California smfikes@smcoe.k12.ca.us

Radio .... Buy at least a four CHANNEL radio - you are going to need at
least one channel for the throttle. Brand and AM or FM is up to you
(ask what others are using). Stay away from Channel 20 they
are banned at many a flying site.

Batteries .... Use only SCR (Sanyo, red, sub-C, rapid charge) batteries
(1000, 1400 or 1700 mAh or the new Sanyo 2000's). The smaller 800 mA AR
cells have higher internal resistance; they work OK but get hotter if
you try to draw high currents from them (500AR Sanyos are great for
Speed 400's). Avoid the yellow, car battery packs - they don't like
fast field charges. If your kit calls for a 6 cell pack, put in a 7
cell - the difference is amazing!

Battery charger .... Buy only a Peak Charger, and buy one that will
charge more than 6 or 7 cells. You may want to go to larger motors
later, and it is better to spend the money for only one, good charger at
the start. Get one that will charge at least 16 to 18 cells. And if
you don't continue with silent flight, you can sell a "good" charger
easier.

Which charger?.... the Astro 110D peak detector charger is a good
choice. It will charge from one to eighteen cells.

Speed controls .... Spend the money to get a good speed control. Don't
buy a "Frame Rate" control - they make geared motors run rough at
partial throttle and draw more current at reduced throttle than at full
throttle (frame rate controls CAN be used with direct drive models that
will run only OFF & FULL THROTTLE). Choose a "High Rate" (1500 Hz PWM
rate or higher) speed control that will handle the current that you will
want, even with larger motors you might get later.
• There are two types of speed controls available - those that use
a receiver battery, and those with B.E.C. (battery eliminator circuit).
If you choose a B.E.C. control, BE SURE TO BUY ONE THAT HAS B.E.C. AND
AN AUTO CUT-OFF! The B.E.C. control draws its operational voltage from
the motor battery, saving the weight of the receiver battery, and thus
the receiver voltage is charged each time the motor battery is charged.
Without the auto cut-off, all the voltage goes to the motor, and there
is none left for the radio! The auto cut-off feature cuts off the motor
when the voltage lowers and saves power for the radio.

Which controls?.... the Astro 217D is a good non-BEC speed control as
are all Astro controllers. It will handle up to 25 volts, 30 Amps (6 to
16 cells). The Novak “Arrow” is a good BEC speed controller with an
auto cut-off, but only for 6 to 8 cells.

What does MOSFET mean?..... MOSFETS are the solid-state devices in a
speed control that switch the current off and on to control the motor
speed.

What is a High Rate Control?.... High Rate means that the MOSFETS turn
off and on the motor current at a high rate (1500 cycles/second or
more). The higher the rate, the better (it runs cooler with less loss).

What is "Frame Rate" control?.... Frame Rate means that the speed
control is turning off and on slowly (50 cycles/second). This is what
the old ESC's (electronic speed controls) were - cheap to make, too.
Frame rate controls cause a motor to run hot at anything less than full
throttle. They will work on planes that run at full throttle and then
turned off.

Is rate mentioned in a ESC ad?.... Most catalog listings call it out as
"Switching Rate" in cycles/sec. Seek out the highest rate that is
compatible with the amount of money you want to spend - anything around
1500 or higher is fine.

Motors .... Buy a good motor - one that has replaceable brushes. A
direct drive motor is usually used for "fast" planes (small,
aerodynamically clean). Geared motors are used for larger planes,
gliders and old timers. Geared motors swing larger props at lower RPM'S
and put out more power at lower currents. One thing to keep in mind -
direct drive motors have small shafts and they bend easily on rough
landings. Geared motors have heavier shafts and survive those landings
better.

What motors?.... the Astro series of motors, both geared and direct, are
hard to beat. I like the geared 035 on 7 cells and the geared 15 on
12/14 cells. An excellent ‘low-cost” motor is the Kyosho “Magnetic
Mayhem”. This is available in both reverse timed version for geared use
and a forward timed version for direct drive and sells for about $20.

How are electric motors designated?.... The manufacturers way of
designating their motor is highly non-standard. Astroflight calls their
motors 035, 050, 15, 25 etc. Graupner calls theirs Speed 400, 500,
600, etc. This is an on-going problem with electric flight - at the
start, they tried to equate the electrics with gas engines, bummer!
Think of an 050 motor as equal to an .049 gas - not close but that is
what everyone uses. It has been suggested that watts is a better way
but it hasn't taken hold. A rough guess is to put in the plane a motor
that will give at least 50 watt/pound (that is input power measured with
an Astro Whattmeter). The Whattmeter will give you a reading of volts
in, watts, current in amps (that's your wattage reading for determining
fuse size). When thinking about motor size, remember that an Astro
geared 40 will fly a .60 sized gas model (if lightened right; a whole
different topic!). I fly a .25 sized gas model with an Astro geared
05. Brands like Aveox, etc., have their own designations, all of which
leaves a seriously interested modeler very confused when it comes to
having any idea which motor is comparable to or competitive to another
brand not to mention which ones physically fit into similar planes. I
haven't got an idea how to pick Aveox motors! They give no comparison
to any other brands. I contacted them, they sent me all their info and
I was even more confused! I have stayed away from this motor - there
are still some problems with 'brushless' motors and their controllers.
And they are expensive! But Kirk Massey at New Creations R/C would be
the person to contact with your questions about "what" motor combo to
get.

Connectors .... Replace the connectors in the wiring - don't use the
Tamiya connectors (white) that come with much of the equipment. The
Tamiyas have high resistance and will arc and melt when you least expect
it. Install Astro or Sermos connectors - the Sermos are less expensive
and are sort of the standard with electric flyers.

Arming switch .... Always install an arming switch in one of the power
leads right behind the motor! This is to give YOU control over when the
motor will come on - remember that electric motors, hooked a battery,
can turn on any time, unlike gas models!

Which switch?.... The arming switch is not for turning off and on the
motor; it is just another safety feature. Buy a double-pole TOGGLE
switch at someplace like Radio Shack and get one with a rating of at
least 5 amps @ 125Vac. Solder one wire from the motor (either + or -
lead) to one side of the switch then from the other side of the switch
to the speed control. Use both sections of the switch (if one side of
the switch goes out, you still have the other.

Fuse .... Always use a fuse in your model - if the plane noses over on
take-off or crashes with a charged battery, the motor will try to keep
running. A charged Nicad pack can burn-up your plane or start a fire
before you can get to it. With a speed control that uses a receiver
battery, put the fuse between the motor battery and the speed control
If you are using a B.E.C., put the fuse between the arming switch and
the speed control - you don't want to lose the receiver power if the
fuse blows!

What fuse?..... I use an automotive, blade type fuse, soldered in -
makes a lower resistance unit. The only time I use slip-on connectors on
the fuse is if it is on a plane for traveling and you blow a fuse and
won't have a soldering iron. Always insulate the connections. Fuse
size? Check out the current draw of your motor, at static; if the motor
draws 25 amps, use a 30 amp fuse. This fuse will blow at no lower than
30 amps. This protects the system if the plane tips over and the prop
hits the ground. Only a severe stoppage of the prop will blow the fuse
- if there is any question, use a larger fuse!

Props .... A good prop to start with on geared motors is the Electric
Master Airscrew wood prop - light and with undercambered blades. Great
thrust! APC props are good on direct-drive motors.

REMEMBER - THERE ARE NO DUMB QUESTIONS! WE HAVE ALL
ASKED THEM. THERE IS NO NEED FOR YOU TO RE-INVENT THE
WHEEL - ASK, ASK, ASK!

This goes without saying - "Make your aircraft as light as possible".
Weight is the enemy of electric flight - there is no vibration nor any
fuel residue so no heavy reinforcements are needed. Try for an airframe
weight that is no more than the combined motor and battery weight. Work
towards the lowest wing loading - if you are converting a gas kit, the
easiest way is to add an extra bay or two to the wing (make the wing
longer). This adds very little weight but greatly adds to the wing area
(thus reducing the wing loading/sq.ft). Use as little epoxy in the
construction as you can. Use epoxy for wing joiners and to glue plywood
- and don't put glue fillets on the parts; it does nothing but add
weight! You CAN'T make a plane crash proof no matter what you do, so
build it to FLY! A good model type to start with is an electric powered
sailplane - but put on a landing gear, it will save your fuselage and
prop shaft as you learn...

Good beginning electric kits ..... One of the best is the "Amptique"
by Spirit of Yesteryear, sold by New Creations R/C. I am still flying
mine after 5 years, but you have to build it. It is a simple build,
though. With an Astro geared 05 motor on 7 cells, it makes a great
sport flyer and with a 12x8 Master airscrew folding prop, makes a decent
thermal glider. If you use an Arrow speed control (by Novak) with this
set-up, you can eliminate the receiver pack (it has a battery eliminator
circuit). If you want to use a receiver battery, install an Astro 217D
speed control.

Other kits, planes
• Great Planes ..... PT-Electric, Spectra, ElectriCUB,
• Goldberg ..... Electra Deluxe, this is an excellent kit and flyer
- comes with
direct-drive motor but easy to convert to geared one. Readily
available at most
hobby shops.
• Goldberg: Mirage 550 .... Another good kit - well designed and
good taildragger
trainer. Can be modified easily to aileron trainer

Thundertiger.....Windstar EP ARF (this is a prebuilt electric, is a
little heavier than one you could build but I have flown many of these
and they fly well, right out of the box). Pretty fast for begimmers,
ask for help when first flying.
Others .... contact Modelair-Tech for other kits and plans(good source
for Speed 400
planes).

Articles for newcomers?.... A good place to look is in the Model
Aviation Magazines (AMA), Bob Kopski's columns throughout the years have
had excellent articles on beginners electrics. Model Airplane News and
Flying Models also have good electric information. New Creations R/C
has some books in their catalog that will help.

Ecalc or Motocalc programs?.... I haven’t gotten involved with Ecalc or
Motocalc - there are too many variables that creep in to the figures and
you still will have to go out to the field with a handful of props and
actually try it in the air!

Adhesives .... Most modelers use CA glues (Cyanoacrylate), instant glue
- but keep in mind that there are two kinds: Regular and Odorless. Both
kinds can be used with an Accelerator which makes them dry even faster.
Regular CA is the least expensive and will dissolve foam! The Odorless
is more expensive, will not dissolve foam and is used by those who may
have an adverse reaction to the regular CA. I can’t use the regular
because it causes my sinus to go crazy and I get laid up for days.
Regular woodworking alphatic glues can be used as well as the old
stand-by, Duco cement. Epoxies (two part) should be used with care in
electrics - it weighs a lot. Use it only for high stress areas like
dihederal braces, firewalls, etc. and use the minimal amount necessary
to do the job.

Speed 400’s .... Here is an update on my Speed 400 sport modeling (not
racing)- I have just started to play with these - they are a BLAST! I
use the 6 volt version of the motor with 7 cell packs (500 AR rapid
charge, red Sanyos). I am using the Jeti 10 ESC (with a brake if you
want to use a folding prop). I’ve found the Cirrus CS-20 servos to work
well and are tiny at about $20 each. For props, I use Graupner 6x3
folders, Master Airscrew 5.5x4 plastic and Rev-up 7x3 wood. Use a prop
coupler from Robbe, #4179, for fixed props. Use Ultracoat ‘Lite” for
covering. I shoot for around 200/220 square inches of wing for
direct-drive S400. Try building Bostonian rubber models at 200%
enlargement - they fly great. Shoot for 16 ounces weight RTF. Buy your
supplies at San Antonio Hobby Shop, Mountain View, Ca - they carry a
good stock of Speed 400 stuff and other electric supplies. New
Creations R/C (Texas) is also a good place to mail order supplies - they
have it all and ‘know’ electrics. Also check with Tom Hunt at
Modelair-Tech for Speed 400 airplane plans and kits.

Safety tips
• Electric motors are different from anything else - they can start
up at ANY TIME. They are like guns - “Oh, there are no bullets in it”.
And you think there is nothing hooked up!
• Don’t run motors while held in your hand - don’t laugh, people do
and it will eat up parts of your body before you can shut it off.
• When you are working on the plane in your shop, REMOVE THE PROP!
You may be only adjusting the radio, setting control throws, etc. but
you will be suprised how fast it goes across the shop, digesting things
along the way!
• Don’t transport planes in the car with a motor battery in it - you
don’t want it flying around INSIDE with you!
• In the pits at the flying field, ALWAYS point the plane AWAY from
people - if you leave the receiver switch ON and turn OFF the
transmitter, any stray RF signal can start your plane! The best way to
be safe is to REMOVE the motor battery AS SOON AS YOU ARE DONE FLYING!
• Always use an arming switch, especially if you have a “powerful”
plane (ie; BIG). It gives you a place to grab and “silence the beast”
if something goes wrong.
• Always check the frequency board to see if ANYONE else is on your
channel BEFORE you switch on. This could prevent crashes, expensive
repairs and lawsuits!

WHERE, WHAT and WHO... (just some of many)

Best battery prices!
B&T R/C Products
508 Lake Winds Trail
Rougemont, NC 27572. (919)471-2060

"Complete" catalog of Electric Flight
NEW CREATIONS R/C
P.O. Box 496, Willis, TX 77378
(409)856-4630 (call for FREE catalog)

Sheldon's Hobbies
2135 Old Oakland Road
San Jose, CA
(408)943-0871

San Antonio Hobby Shop
2550 El Camino Real (behind Sears)
Mountain View, CA
(650)941-1278

J&M Hobby House
1660 Laurel Street
San Carlos, CA
(650)593-5019

D & J Hobbies
96 San Tomas Aquino Road
Campbell, CA
(408)379-1696

Radio repair & tuning
S&D R/C SERVICE
4500 Stevens Creek Blvd.
San Jose, CA 95129
(408)345-2278

Omni Models
P.O.Box 708
Mahomet, IL 61853-0708
1-800-342-6464
Call for catalog

Tower Hobbies
P.O.Box9078
Champaign, IL 61826-9078
Mail order firm
1-800-637-4989 or 1-800-637-6050
Call for catalog

Hobby Lobby International
5614 Franklin Pike Circle
Brentwood, TN 37027
Mail order firm - lots of electric stuff
1-615-373-1444

MODELAIR-TECH
PO Box 1467
Lake Grove, NY 11755-0872
(516)981-0372
Email THunt95147@aol.com

Model Research Labs
25108 Marguerite #160
Mission Viejo, CA 92692
Fax only (714)248-1074
Website www.BESTPC.COM/MRL

Here are some of my Web page addresses - there are a million more out
there.

http://www.hrunway.com ...............................................(buy & sell page, etc.)
http://www.aveox.com brushless motors)
http://www.ama10.org/ ...................................(AMA District 10 homepage)
http://www.modelaircraft.org/ ...........................................(AMA homepage)
http://www.astroflight.com/ .........................................(electric motors/products)
http://www.dejanews.com/ ...................................................(news group)
http://loke.as.arizona.edu/~ckulesa/flight.html ...........(High Voltage - Electric Q&A)
http://www.newcreations-rc.com ..........(outstanding R/C catalog site)
http://www.ezonemag.com/ .................................(Virtual home of electric flight)
http://www.modelairtech.com ...........Tom Hunt, Speed 400 plans, equipment, etc.
http://www.towerhobbies.com/rcweb.html ......................(Tower Hobbies)
http://members.aol.com/KMyersEFO/ .....(Ken Myers homepage-Excellent)
http://members.aol.com/kmyersefo/page6.htm#TOP .............(NEAC clubs & reps)