| T.R | Title | User | Personal
Name | Date | Lines |
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| 904.1 | Go for the geared. | ROCK::MINER | Electric = No more glow-glop | Tue Feb 28 1989 18:15 | 20 |
| I have not seen an electric motor in a Olympic 650 although I see
no reason why it shouldn't work well. Just be sure that the center
section of the wing is strong enough for the extra weight of the
motor batteries.
For an electric motor glider, I would recommend an Astro Cobalt 05
GEARED. The direct drive would also work but not quite as well.
Also, the motor shaft is more likely to get bent on a direct drive
than on a greared motor.
_____
| \
| \ Silent POWER!
_ ___________ _________ | Happy Landings!
| \ | | | | |
|--------|- SANYO + ]-| ASTRO |--| - Dan Miner
|_/ |___________| |_________| |
| / | " The Earth needs more OZONE,
| / not Caster Oil!! "
|_____/
|
| 904.2 | good choice | LEDS::COHEN | | Tue Feb 28 1989 20:23 | 20 |
| I second Dan Miner's opinions. The 650 is very similar to the current
glut of electric powered gliders, like the Electra and the Airtronics
Eclipse (or something like that, anyway), and ought to work quite well.
I also second the recomendation for a geared motor. There are two
important reasons. One is, of course, that the cobalt motor is
expensive, and anything you can do to minimize the risk of damage is a
plus. Direct drive motors constantly bend armature shafts when landing.
The other reason is one of efficiency. A geared motor works better,
making more effective use of the energy available, than a direct drive
motor. Why, you ask ? Well, a glider is a big, slow plane. You want
to power it with a Big Slow Prop. You make more efficient use of the
energy available, since you're not wasting power spinning a little prop
wicked fast in order to produce the forces you need to fly (Drag goes up
with the cube of velocity, and stuff like that. Also, from empirical
evidence, my electric motor glider flies much better with a 3:1 geared
540 sized motor and a 12-8 folder than it ever did with a 550 sized
motor with an 8-4 on direct drive).
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| 904.3 | no mods - keep building... | K::FISHER | Only 14 Days till Phoenix! | Wed Mar 01 1989 11:15 | 61 |
| > I'm currently in the process of building an Olympic 650 glider.
> This is my first glider though I have a Kadet Jr. that I have flown
> on many occassions. I have the tail feathers constructed and am
> almost finished with the wing. I should be starting on the fuse
> fairly soon.
Mike both replys so far are good advice - but let me give you something to
think about. The Olympic 650 is a great glider. You should build it stock
and forget about the electric stuff for several reasons.
1. I assume from your experience with the Kadet Jr. that you have not built
a lot of planes before. Things are hard enough with kits shipping bad
wood, poor instructions, parts that don't fit quite right, etc. If you
attempt this (non trivial) modification your just asking for trouble.
2. It is not documented how much down trim, etc. you might need.
3. It will cost you $200 plus to do it right. Geared 05 Cobalt = $100 plus.
Electronic throttle = $40 plus, Good batteries = $40. Good charger = $70.
Good folding prop = $20, plus expensive experiments to find the correct
size prot, etc.
4. Without a lot of flight time powered gliders are difficult to control.
I'll get an arguement here from other noters but I think that because
you really must fly the glider on the wing that it is very easy to stall
and put it in the ground on launch or during an aborted landing.
5. If you get a high start and start spend two weekends with it, then
start following the glider competitions I can almost guarentee you will
have a very enjoyable summer. Anker and Dave Walter and I all attended
glider competitions this summer and we all flew gliders for the first
time this summer also. Great fun, great people, great flying sites, etc.
Also I had a ball at my first competition and I came in last place in
all three classes.
6. Dan Snow is selling a high start right now for $25 - that is about $15
off list and Dan washes it and packs it in baby power every night :-)
7. A purist would not consider an electric glider a glider. There is something
magical about launching with a high start and catching a thermal that is
difficult to explain. There is a thrill when you catch your 1st thermal
and there is a thrill when you catch your 100th thermal. It's kinda
like perpetual motion - you really feel like your getting something
for nothing.
Now I kinda like the exectric stuff also and in fact plan to build a Thermal
Charger soon after my trip to Phoenix - but I suggest you wait and if you
still want an exectric glider then purchase one that is designed that way
from the ground up.
Eithor way - if you're in Mass. bring your completed project into the
DECRCM meeting for show and tell - I'd like to see it tho I will miss
the 14-Mar meeting.
Bye --+--
Kay R. Fisher |
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| 904.4 | Back on track | AUGGIE::SEGOOL | | Wed Mar 01 1989 11:33 | 18 |
|
Thanks for the replies. Kay, you had some very interesting points
to make. I think that a little but of it had entered my mind when
I decided to buy a glider instead of a powered glider. I should
point out that I have been building off an on, though mostly off,
for many years, but I think your point about modifications is still
valid.
My main reason for thinking about powering the glider was to make
launching easier. But I had always thought that adding a motor to
a glider sort of took away from the concept of gliding, freedom
from mechanical power.
Maybe I will stay with my original idea, and leave the 650 motorless.
Thanks for the replies and thanks Kay for steering me back to my
original idea of what I wanted from this plane.
Mike
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| 904.5 | Strap on power without the glop? | TEKTRM::REITH | Consultants do it by the hour! | Wed Mar 01 1989 12:36 | 9 |
| I've got a question that this topic has brought up in my mind. When I was flying
gliders in High school we didn't have a big enough field to stretch out a high
start so I designed and built an .049 power pod. It had hooks to go over the
rear wing dowels and got secured with the hold down rubber bands. It mounted
over the CG so it didn't affect the balance much.
My question is, has anyone built/designed/flown an external, pylon mounted,
removable, electric power pod? This lets the glider use high starts when
available but you can have fun in a small field too.
|
| 904.6 | Try this | HEFTY::TENEROWICZT | | Wed Mar 01 1989 13:54 | 21 |
| What the bother?? I cant see building a glider and then installing
an engine in it. If short fields are the issue try this. Buy a
std high start, the short field one. Also get/make a second stake.
Rather than securing the line to the tubing slip a steel loop over
the tubing and attached the line to this tube. Now stake both ends
of the tubing down app 40ft apart from each other. When the line
is deployed it will seek the center of the tubeing. When it's streached
it will form a triangle shape. It will deliver the force of the
long tube but with only half the needed distance.
Tom
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| 904.7 | Tom has an interesting idea... | K::FISHER | Only 14 Days till Phoenix! | Wed Mar 01 1989 14:39 | 59 |
| > it will form a triangle shape. It will deliver the force of the
> long tube but with only half the needed distance.
Same force in half the distance = folded wing.
Two can live as cheaply as one - for half as long.
If you get the heavy duty high start you can just shorten the tubing
with a knot for short fields. In general the short high starts (Up Starts)
don't get you high enough to be happy. The first time I used a real
high start instead of my Up Start was the last time I ever used my
Up Start.
Tom - don't flame me.
Tom is right in his idea and you can judge the pull as you stretch the
line and have a good feel for how much you want to pull.
One problem with the Y would be:
Consider that you only do this where you have limited space.
Then you must have a small patch within which the Y fits.
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Now it the wind is from straight ahead ^ OK.
But if it is off by any angle then the ring will travel to
the left or right end of the rubber and the parachute will
always fall into the trees on the boarders.
There is probably no way in tree infested Massachusettes to avoid
the walks to keep moving the high start anchors as the wind shifts.
Except with batteries on your next plane. After you're cooking with
gliders then use electric assist gliders for practice and real
gliders for competition.
Bye --+--
Kay R. Fisher |
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| 904.8 | Could use lighter packs for a 2 minute run... | TEKTRM::REITH | Jim Reith DTN 235-8459 HANNAH::REITH | Wed Mar 01 1989 16:00 | 17 |
| I guess my idea was not to spoil a nice 2 meter - 100" glider by modifying it
to be full time electric (that's what electric kits are for ;^) but to allow
the pilot to hop out to a less than ideal field and toss it into the wind and
still have a sleek high startable model.
I didn't have an engine cutoff on my .049 pod and I would think that it
wouldn't be hard to wire in a below a certain voltage cutoff into the electric.
I have always thought it would be neat to not have the glop on the glider just
because I was too lazy to drive (and lose time for a flight or two) to the field
with the high start. Besides, I've folded plenty of wings on a high start but
none on a power pod (unless you count that inside loop/figure question mark ?)
I like popping over to my neighbor's field with the street still hot and the dead
calm of dusk for a flight or two.
I have neighbors that have small fields and are much happier if I bring an
electric. Then I have no frequency competition or novices stuffing one into my
pit. I fly much better without the hot dogs making inverted passes by my ear.
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| 904.9 | My .02 cents on the OLY 650 | USRCV1::BLUMJ | | Wed Mar 01 1989 18:30 | 10 |
| I also built the OLY 650 as my first glider. It was a real slow
and forgiving ship. However, it has very mareginal penetration
abilities which cause problems when flying in wind in excess of
about ten mph. Without ballasting it is difficult to stay or get
back up wind. Ovberall <I enjoyed this glider very much. Good
luck on yours!
Regards,
Jim
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| 904.10 | Silence is Golden!! | NEXUS::PAGE | | Thu Mar 02 1989 12:33 | 23 |
|
Mike;
I would like to thank Kay for trying to discribe the feeling of
your first (or 100th) thermal ride, you'll never forget it. here's
another point that I dont think was brought out. I started with
an Electra so I know from where I speak.
the electric takes some time and talent to get up to altitude. Its
a bit of a battle keeping the glide path just right to get as much
altitude as possable without stalling. Then you watch someone hook
onto a highstart or winch and ZOOM their up there 400 feet and thermal
searching while your still sweating around with your electric motor
going full blast.
there is a place for the electric's and they are fun. BUt there
is nothing like 'silent flight'..
Good Luck.
Bob Page
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| 904.11 | Hear Hear | CURIE::ANKER | Anker Berg-Sonne | Thu Mar 02 1989 13:47 | 55 |
| Re:< Note 904.10 by NEXUS::PAGE >
Hear, hear!
I got into gliders really stupidly. The CRRC was hosting
a big glider contest last August and just over a week before I
decided I really would like to get into them, and why not for the
contest. So I swung by Tom's, looked over his kits and took a
Topflite Metrik and a high start home. Over the next week I
built like crazy and got it ready 1AM Saturday morning.
After a few hours sleep I got out early to the field,
hand launched a few times, tried the high start and then the
competition was on! So on day 1 I had to learn how to use a
winch.
Amazingly I made it to the middle of the pack, mainly due
to good coaching by experienced glider pilots.
After Saturday's contest I managed to crash into a chair
on landing! So Saturday evening I was busy patching the wing
together again.
Sunday I forgot to turn my transmitter on when launching
the second time and broke the plane pretty bad, so the rest of
the contest I used a borrowed Gentle Lady and did well enough,
but in the bottom half.
The next weekend I went to Callahan State Park and found
my first big thermal and had a 10 to 15 minute flight. Of course
I was hooked from then on. The gratification you feel from
having found a thermal and seing your glider go up like a shot
simply cannot be beat.
I am still pretty inexperienced, but I ussually find a
thermal in one of three launches.
Its great fun and not nearly as hard as "they" claim.
What did I learn? It was the wrong glider first of all.
A flat bottomed Gentle Lady, SIG Riser or Olympic would have been
much better. I also learned that its a lot easier to become
airborne without a radio connection and have learned to jiggle
the controls EVERY time I hook it onto the high start.
_
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| | o \
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Hang in there! o_|_
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Anker \_|_/
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| 904.12 | Goldberg Electric Pylon | WR2FOR::BEATTY_WI | | Sat Mar 04 1989 15:08 | 9 |
| I couldn't resist putting my two cents worth in on this one, have
you considered the Goldberg electric pylon??? I takes no major
mods to the glider, you can get two three cell sticks and strap
them on under the wing at the root and its perfect for the OLY 650.
Power up and thermal around!
Regards,
Will
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| 904.13 | Go for a Cobalt motor | ROCK::MINER | Electric = No more glow-glop | Thu Mar 09 1989 21:54 | 54 |
| RE: < Note 904.10 by NEXUS::PAGE >
> the electric takes some time and talent to get up to altitude. Its
> a bit of a battle keeping the glide path just right to get as much
> altitude as possable without stalling. Then you watch someone hook
> onto a highstart or winch and ZOOM their up there 400 feet and thermal
> searching while your still sweating around with your electric motor
> going full blast.
If you are talking about a standard Electra with one of those
(crappy) stock car-type motors, then I have to agree with you.
However, if you use a Cobolt geared motor, I STRONGLY disagree with
you. An Astro Challenger (or Goldberg Electra) with an Astro Cobalt
05 geared will climb to "high start altitude" with authority (NOT
near stall speed) in 20 to 30 seconds. If you choose an Astro
Cobalt 15 geared, it will climb at about a 60 degree angle and get
to "high start altitude" in about 10 to 20 seconds. Since total
motor runs are typically in the 5 to 8 minute range, you can get
many climbs to altitude on one charge of the battery.
In my opinion, it's much more convienent to not have to un-spool and
re-spool a high start. Also, on a day where the lift is minimal (or
non-existant) an electric motor glider can spend 8 to 20 minutes
searching where a "true" glider has only 45 to 90 seconds. The
motor glider can search further away from the launch area for lift.
In other words, the motor glider can reach lift that a glider could
never get to.
On the negative side - adding a motor, battery, and speed controller
are just useless ballast when you turn off the motor. A motor
glider does not glide as well as its un-motored glider cousin since
the wing loading is increased. (Note: this ballast does help you on
windy days when a light floater glider gets blown downwind.)
All in all, (in my opinion), an electric motor glider is the best
way to learn how to fly a glider since it gives the pilot more air
time per flight.
Enough of my talk. If you wish to read more of my thoughts and
opinions on electric flight, do:
Notes> dir/author=Miner 387.*
_____
| \
| \ Silent POWER!
_ ___________ _________ | Happy Landings!
| \ | | | | |
|--------|- SANYO + ]-| ASTRO |--| - Dan Miner
|_/ |___________| |_________| |
| / | " The Earth needs more OZONE,
| / not Caster Oil!! "
|_____/
|