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Old Jun 09, 2010, 10:08 AM
Out of helis, sanity returning
Tallahassee, FL
Joined Feb 2009
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Originally Posted by srnet View Post
Possibly, but if the plane is launched with the wings horizontal, why would it pull to the left at all ?

The only thing I can think off is if the rear of the tail is bent by the spin to the left giving a bit of effective left rudder.
My theory is that the launch peg in the left wing creates enough drag to pull the plane to the left

Rick
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Old Jun 09, 2010, 10:16 AM
Stuart
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UK, Cardiff
Joined Dec 2008
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Originally Posted by John255 View Post
These are wild guesses, but if the right wing has less wash-out than the left at high speed it will have greater lift and do much the same thing as an aileron. Who knows???
John255
But then you expect some reports of the plane pulling to the right.
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Old Jun 09, 2010, 10:18 AM
Stuart
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UK, Cardiff
Joined Dec 2008
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Originally Posted by 2400RDR View Post
My theory is that the launch peg in the left wing creates enough drag to pull the plane to the left

Rick
I have tested that, I put the plane into a high speed vertical dive (not intentionally) it went straight down and did not pull to the left .......
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Old Jun 09, 2010, 10:48 AM
Out of helis, sanity returning
Tallahassee, FL
Joined Feb 2009
2,142 Posts
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Originally Posted by srnet View Post
I have tested that, I put the plane into a high speed vertical dive (not intentionally) it went straight down and did not pull to the left .......
The thing about the peg was, well, a joke, sort of.

When I was trying to solve my "pulling to the left" problem, I took the wing off, put it on my building board and did some fairly careful measurements. The wing appears to be straight, with polyhedrals equal on both sides, and no difference in washout that I could see, no warps, and so forth.

Seriously though, these things are designed to fly slowly, and I figure that traveling at high speed during launch is bound to magnify any little errors that were built in, and which probably wouldn't be noticed during normal flight.

It is interesting that most people who report hooks say it is to the left- you'd think that if were building errors, you might see some right hooks too. I wonder if lefties get right hooks?

Maybe it's Coriolis Effect?

Rick
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Old Jun 09, 2010, 10:55 AM
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Teezer's Avatar
Pagosa Springs, CO
Joined Jul 2007
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Originally Posted by glider90 View Post
~1.5min mark: Unmistakable and gut wrenching sound of freshly ironed Micafilm covering screeching across 30 tall pine tree needles. Depth perception score today, F-.

...

Glad to have my Gambler back, flying, and out of the tree.
~Jim
Ha! Great post, and great documentation, too.

I have a dozen 40-50 foot pine trees on my property, so I know the feeling all too well. Both of my small, hand-launch gliders (an Alula and the Gambler) have patches of velcro on the fuse under the wings. I have a thirty-foot pole (the handle of my snow-season roof rake with a couple of green garden poles taped on with duct tape) with a velcro flap at the tip. With this velcro wand, I can usually grab the glider out of the tree directly.

Sometimes I need a ladder to give me greater reach, but I've not had to actually climb a tree since I've done the velcro thing...
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Old Jun 09, 2010, 11:04 AM
Stuart
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UK, Cardiff
Joined Dec 2008
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Originally Posted by 2400RDR View Post
The thing about the peg was, well, a joke, sort of.
I realized.

I would not however recommend the carrying out of the destructive test that I did.

I doubt its wing building problems or you would expect equal numbers of right hand throwers to report pulling to the right and left.

If you attach the power pod, the gambler is capable of flying quite fast and at such speeds the controls are very sensitive, it can be a handful to fly in level flight.

Coriolis ?

So if you stood one step south of the equator it would pull one way , but a metre further North and it would pull the other way? If that theory was correct it should first pull across the equator then come back the other way and continue oscillating this way as it climbed
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Old Jun 09, 2010, 11:16 AM
Stuart
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UK, Cardiff
Joined Dec 2008
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Originally Posted by Teezer View Post
Both of my small, hand-launch gliders (an Alula and the Gambler) have patches of velcro on the fuse under the wings
Thats a good tip.

I do keep a 8m take apart carbon fishing pole in my car, like this;

http://www.gooutdoors.co.uk/shakespe...rt-pole-p96913

Been handy more than once.
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Old Jun 09, 2010, 11:21 AM
Gambler-AG DLG Designer
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Lee, NH, USA
Joined Jun 2001
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Originally Posted by 2400RDR View Post
It is interesting that most people who report hooks say it is to the left- you'd think that if were building errors, you might see some right hooks too. I wonder if lefties get right hooks?
The number of people reporting this is proportional to the number of right-handed owners. Lefties experience the opposite effect. I'm going to go back to my standard answer here. Most people experiencing this should re-examine their launch. It's quite likely that the source of the problem is located between the launching peg and the ground

The release point for a DLG during the launch is much earlier than any other 'throws' that the typical person has experienced (ball, Frisbee, boomerang, hand grenade, javelin, even a 'real' discus). Most first timers are releasing late and causing the left hook (for right-handed people) because of their launch. I know this from my experience teaching 40-50 people how to launch the Gambler in person, it's not just a blind guess.

Some people buy 'anti-slice' golf drivers. In RC we have launch presets that can do the same thing. If they help you, that's fine with me. Use them. Just know that you can launch straight if you modify your technique.
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Old Jun 09, 2010, 11:43 AM
Out of helis, sanity returning
Tallahassee, FL
Joined Feb 2009
2,142 Posts
Quote:
Originally Posted by srnet View Post

Coriolis ?

So if you stood one step south of the equator it would pull one way , but a metre further North and it would pull the other way? If that theory was correct it should first pull across the equator then come back the other way and continue oscillating this way as it climbed
Right, the the plane would be impossible to fly at the North or South Poles because it would go into an uncontrollable flat-spin on launch

The preset works just fine for me- it funny that it's a point of contention. I'll maiden a TopSky in a couple of weeks and see how it goes with that- should be a cool comparison.

I do believe that the Gambler can be launched without presets, just not by me at this point in time. I'm a relative newb. I feel happy to be flying in a time when there are computer radios and programmed preset mixes are possible. There was no such of a thing the first time I did RC 25 years ago.

It's all good.

Rick
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Old Jun 09, 2010, 03:41 PM
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powder springs georgia
Joined Nov 2003
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Will someone explane this to me.. I am trying to learn hear.. I just do not understand..
If you have NO up trim at all in the elevator and the cg is at neutral, In a dive it stays at the same angle all the way down... Then how is it going to climb on a launch if you throw it level or parallel with the ground..What makes it climb ?? I am missing something...Like I said earlier , mine will climb at about 45 degrees and I think thats because I might not be parallel to ground...at release,, would I need to put some up in the release or release sooner ??
Be kind.. Thanks...
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Old Jun 09, 2010, 04:02 PM
Stuart
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UK, Cardiff
Joined Dec 2008
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Originally Posted by sanman55 View Post
Then how is it going to climb on a launch if you throw it level or parallel with the ground..What makes it climb ??
More speed = more wing lift ?
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Old Jun 09, 2010, 08:20 PM
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powder springs georgia
Joined Nov 2003
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Then why won't my throws go near verticle??
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Old Jun 10, 2010, 02:28 AM
Stuart
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UK, Cardiff
Joined Dec 2008
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Originally Posted by sanman55 View Post
Then why won't my throws go near verticle??
If it were thrown fast enough it will eventually go past vertical into a loop.
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Old Jun 10, 2010, 09:26 AM
Registered User
Pensacola, FL, USA
Joined Dec 2000
3,235 Posts
Very good point Stuart.
Hand launchers are always throwing up, but are rarely sick.

There is another area variability for launch and trim problems sometimes overlooked and that is servo centering. Unlike other applications in RC, gliders demand perfect centering especially on the elevator. I've found new servos of several popular brands to be off right out of the box.

As the photos show it's quick and easy to test servos before and after installation. One reason I like Hitec brand is they will repair servos, most of the time for free. Most other brands I just use on power planes where stick input is almost continuous.
Regards,
John255
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Old Jun 10, 2010, 10:20 AM
Stuart
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UK, Cardiff
Joined Dec 2008
3,328 Posts
Having flown the Gambler at high speed, with the power pod on, I can report it is very sensitive to elevator control.

So I can see that for high speed launch, slop in the servo connection or poor centering will lead to inconsistent launches.
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