Adam's reflections on an electric year

[Adam Glatt]

I received the bottom email a few days ago.  Above it is my response.  
I'm sending it to the list to inform.
-Adam

--------------------------------------------------

Hi Toru.

1)  Electric power had numerous appeals for me.  Electric power was 
innovative and interesting.  Electric power flew different than gas 
power.  Electric power cost me less money than gas power.

2)  There is a lot to learn to successfully run electric in F3A.  I did 
a lot of research and had experience with small electric planes, so I 
didn't encounter any big problems with the electric power system

3)  The airplane flies better in almost every way with electric power.  
The only downside is the increased slipstream effect compared to gas 
power.  Electric planes roll nicer and pull through radii better.  Speed 
is much easier to control with electric.  With gas, a small throttle 
mistake can result in the plane going far too fast.  With electric, the 
plane can not go too fast.  Knowing your motor is still running as you 
exit every spin also allows me to concentrate more on flying.

4)  Three parameters define how an electric motor will perform.  
RPM/volt, efficiency, and weight.  Efficiency is extremely important, 
because an inefficient motor must be much heavier and requires heavier 
batteries.  RPM/volt determines whether you run a 19" or 21" prop, which 
makes a big difference in the performance of the airplane.  Weight is 
less important because my plane was well below 5kg (4.73kg), and felt 
very light in the air.  Almost too light.
Two parameters determine how good a battery is for F3A: energy density 
and power density.  F3A is unique in that we require a 10 minute flight, 
while also running long periods of very high discharge.  For a battery 
to be optimized for F3A, its capacity must be what is required to fly 
10-11minutes, and it must put out as much power as you demand in windy 
uplines for up to 30 seconds.  When choosing a battery, first find the 
lithium polymer cell with the best energy and power densities.  Then, 
put together enough of those cells to give you the required power and 
energy for an F3A flight.

5)  It takes a lot of batteries to fly as much in a practice evening as 
I used to with gas.  However, a practice session with a given number of 
flights is much shorter with electric power than gas, because electric 
is much easier and faster to set up and run at the field.  If you are 
used to flying more than three times with gas power, when you switch to 
electric you need to invest in at least three sets of batteries.  If you 
only buy two sets of batteries, you will spend a lot of time waiting for 
chargers at the field to get in four flights.

6)  Electric motors are still being developed that will eventually offer 
a complete selection of kV (to match the pilot's style of flying), while 
also being highly efficient.  Batteries improve every year.  With each 
improvement, the previous technology becomes much less expensive.  I 
believe the best batteries this year are as good as we need for F3A, 
however the price is too high.  Next year (2006) that price will almost 
certainly be much less, and electric will be attractive and affordable 
for a many pilots.

7) I plan to fly electric next year.  In fact, I hope I never run 
another gas motor.

-Adam Glatt
Saskatoon, Canada


denpa wrote:
> Dear Mr. Adam Glatt,
>
> Thank you for your cooperation when I took photos of your splendid 
> airplane in this time W/C. I will print your model on the Radio 
> Control Technique magazine, so I ask a favor of you, would appreciate 
> if you let me know about the following questions;
>
> 1)Why do you adopt Electric powered model instead of Gas powered one?
>
> 2)Have you had any trouble on handling Electric powered model?
>
> 3)What is the difference between Electric powered model and Gas 
> powered one on flying it?
>
> 4)What do you take into consideration on choosing the motor, propeller 
> and battery?
>
> 5)I suppose that the number of flight is reduced in case of Electric 
> powered model. How do you overcome the situation?
>
> 6)How will Electric powered model evolve, do you think?
>
> 7)Will you continue to adopt Electric powered model in future?
>
> Thank you very much in advance, I will be waiting for your kind reply.
>
> With best regards,
>
> Toru SUEHIRO
>
> Editor, Radio Control Technique, Japan.
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