| I am flying electric, (amongst other things) and up to now
I have flown four different gliders.
- The firts one was a Flying wing called GEIER, a kit produced by
Robbe. I was using 8 cells pack, Mabuchi 550 motor with a direct
drive on an 8x4 prop. Motor installed in push mode. Not a very
efficient design. Flew well with motor on, quite touchy in glide.
- The second one was a 4 channels 2 meter glider built from plan.
8 cells pack, Mabuchi 550 with reduction gear 3/1 and folding prop.
Profile E193. Typicall 3.5 minutes motor time. Typical flight, 9
minutes without thermal. Somewhat sensitive to tipp stall. Needed
to be flown quite fast.
- The third was is a Diamant from Robbe. 130 inches. E193 airfoil.
16 cells, electronic controller, geared engine from Robbe. (400watts).
Typicall engine run 3 minutes at full power, but much more at reduced
power which you really can use to search for thermals. Typical flight
12 minutes without thermals. But I have done as much as one hour
in good conditions. Super plane.
- I also recently built a Silentius from Graupner. (easy to take
with on holidays) super design, very easy to land in small patches.
I fly it with 8 cells, using the standard Graupner geared drive.
I would recommend an electronic controller on most designs because;
- it allows to fly longer using reduced power to search for thermals.
- it protects the magnets by limiting surge current
- it protects the gear
If you go for an electronic controller, buy one with high chopper
frequency (2000 +)
If you need more information do not hesitate to contact me:
JEAN-PAUL BERGMANS @GEO DTN : 829 9331
Regards
|
| I have had 4 electrics, sort of......
#1 was a stock Etude, 6 cell pack, set up with 4 channel control.
It was a little slow in the climbout, but acceptable for medium
size fields. Really fast on the glide though, I was never able
to land it on grass without breaking a prop, bending a gearshaft
or "pung-ing" the undercarriage.
#2 was a stock Electra, 6 cell pack, 3 channels with a NOVAK NESC-4
speed controller. This I found to be an excellent combo. The Electra
climbs fairly well, with washout its not overly sensitive to tip
stalls, the glide is slow but responsive, the plane is easy to land.
In combination with the speed controller, 10+ minutes of power is
possible, allowing 15 - 20 minute flights with no thermals. Low
throttle is great for hunting up some "rise" without loosing too
much altitude, in sunny weather, 30 to 60 minute flights were not
uncommon. I suggest you replace the "living" hinges supplied with
the kit with pinned hinges though, I lost my plane to an uncontrollable
left hand spiral when the lower of the two rudder hinges fatigued
and gave way.
#3 was an Astro-Sport with an Astro 05 cobalt and a Cox grey 6x4.
I don't know why the Cox grey prop seems to provide better performance
than other 6x4s, but it does. This plane has a 36 inch span with
a semi symmetrical (?) airfoil of the E193 or 195 class (i'm not
sure which), flew with airleron-elevator and the NESC-4 speed
controller. It did this very fast. Too fast, in fact, for my limited
(but improving) abilities, sniff sniff, oh well...
#4 is an ElectriCub, stock, except for the Astro 05 from the, sniff,
Astro-Sport, and an Astro-flight electronic speed controller. I
have yet to fly this plane, but when I do, it will use a six cell
pack of those exciting new Sanyo SCE 1700 MAH cells, same size and
weight as a six cell 1200 MAH pack with 40% more power ( I happen
to have six of these cells courtesy of the Sanyo America sales office
). I still use the 6x4 on it, but with the higher capacity cells,
I might end up with a 8x4 (which only lasts 3 minutes with 1200
MAH cells), since in static tests, the 8x4 pulls almost twice as
hard. A word about the Astro speed controller : This is a very
inexpensive unit (around $40.00) with good low on resistance. Problem,
though, with my Conquest 4NL, full off throttle to on throttle was
not giving me full on at the motor. Called Astro about the problem,
they were very helpful, the chip used in the controller the is servo
driver produced by Signetics (don't remember the #, but there is
only one), and I ended up having to customize my controller somewhat.
Additionally, I have a NEW, what I like to think of as a Sort-of,
Electra. the wing is 8 inches greater in span, and it sports a
V tail. The motor is a stock 550 with a unique (i've never seen
another one) 3:1 gear drive that uses an orbital gear arrangment
so the gear drive output shaft is directly in line with the motor
output shaft, instead of offset. I spin a Master-Airscrew 12x8
folder at a little better than 3000 rpm. this plane has yet to
be flown, so I don't know if the prop is spinning fast enough to
get it up. If it can't climb, I'll try 7 cells, or a smaller prop,
or both.
Also, I have a 4 channel electic made from the Etude wing and the
Astro-Sport fuse, which I haven't finished yet. No decision on
motor/prop/batteries, though I am leaning toward a cobalt 035, a
6x4 or 6x3, and 5 1000MAH cells.
|
| We can't thank you enough for this note!! It probably saved us
another (maybe fatal?) crash with the Electra. My husband's last
flight in the Electra was nearly fatal, and we had no idea why.
Control and turns felt strange on the first flight, 'minor' crash
in, but everything seemed fine. The second flight totally lost
control on a turn, *CRASHED* and snapped the wing, almost destroyed
the tail, plus quite a lot of other 'minor' damage. We've been
going crazy trying to figure out WHY this happened. Our only possible
excuse was interefence (there's a lot of houses and a school right
near the field).
The plane has since been repaired, but we haven't had a chance to
take it out again. We were STILL wondering what happened!
Well, as I was reading through notes, I saw the section about changing
the hinges on the Electra to pin hinges, and mentioned it to my
husband. He took out the Electra, and sure enough (mind you, this
is AFTER it was all repaired), the hinges for the rudder were in
pretty poor shape! The bottom one was broken, and the middle and
top were loose. Back to the drawing board ....
It still seems a little strange that it wasn't noticed earlier,
but he still had full control of rudder, so it 'appeared' fine!
Obviously the stress of flight was too much for it!
(Incidentally, the tail has sustained some pretty major damage in
a previous flight, er crash, which is probably when it broke).
Check them out GOOD!!
and THANKS!!
Patty
|