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Old Sep 14, 2011, 09:46 AM
Russ Young
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United States, UT, South Jordan
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Rudderless launches

I've just started paying attention to DLG's and was wondering:

On a rudderless DLG, how is a straight launch achieved without associated rudder deflection to offset the forces of spinning?

Thanks,

Russ
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Old Sep 14, 2011, 10:05 AM
G_T
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Generally no rudder deflection is used anyway. Modern DLGs are designed not to need it.

Usually when rudder is needed on a launch nowdays, it is due to one of two things. First is technique, where the thrower hooks the launch. Rudder is then a partial correction for poor technique.

Second, it is from not having a stiff enough rudder linkage setup. That includes the pushrod (or pull-spring) and the servo. Skimping in this area is not a good idea.

One problem with using rudder preset on launch is that the timing for releasing it tends to be different than what one wants for releasing the elevator preset.

Gerald
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Old Sep 14, 2011, 10:06 AM
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Russ:

Not to worry: few, if any rudder-equipped DLGs actually have to have rudder input.

The normal yaw stability will usually result in a straight launch, if you release wings level.

I used to use rudder offset on a polyhedral DLG, but eventually, I even straightened that one out.

Yours, Greg
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Old Sep 14, 2011, 10:30 AM
Russ Young
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Thanks guys.

Greg, my only DLG is a 4 year old Gambler AG poly that I only have flown occasionally. I launched it with a bit of rudder offset. I intend on overcoming any launching bad habits when I start up with competition planes.

Russ
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Old Sep 14, 2011, 11:08 AM
hot air rises...
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Hey Russ, be sure to come down to Orem this weekend for the Blue Skies over Utah event (http://www.rcgroups.com/forums/showthread.php?t=1443980). There's still room for more contestants and we would equally welcome spectators.
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Old Sep 14, 2011, 11:30 AM
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So what are the advantages and disadvantages of going rudderless? Bruce Davidson endorses the rudderless approach in the Radio Carbon Art DLG videos. I'm building a Taboo GT and I'm at the decision point to go rudderless or not so your opinions are being solicited.
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Old Sep 14, 2011, 11:32 AM
Russ Young
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United States, UT, South Jordan
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jfinch,

I've been lurking around DLG for a couple weeks now. I'll be there to watch and help(if needed) this weekend...I won't join in the fun this time around...an old Gambler AG would not do too well against modern comp. planes...although, it does find 15' lift on occasion.

Russ
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Old Sep 14, 2011, 11:35 AM
Father of Fr3aK, DLG Pilot
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I'm rudderless. It's one less servo, one less pushrod, one less adjustment, simpler construction, but most of all it's a stiffer tail so you have an airframe that is less compliant at the time of the first yaw excursion. That equates to measurable launch height increase.

Sometimes I wish I had a rudder in flight, but it's not terribly often and it's hard to quantify whether or not it costs me anything in terms of flight time.
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Old Sep 14, 2011, 11:38 AM
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Russ:

I will be at the Blue Skies. Please stop in and ask around.

Yours, Greg
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Old Sep 14, 2011, 11:53 AM
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Quote:
Originally Posted by tom43004 View Post
Sometimes I wish I had a rudder in flight, but it's not terribly often and it's hard to quantify whether or not it costs me anything in terms of flight time.
Tom,

Some say rudder is advantageous in tight strong thermals and slow speed flaps down roll initiation. Oleg, stated he flew a ruderless Taboo and didn't like it, but didn't mention any performance negatives other than odd/different handling that you have to get used to and play with aileron differential to tune-out. Did you use aileron differential?
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Old Sep 14, 2011, 12:16 PM
Father of Fr3aK, DLG Pilot
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Quote:
Originally Posted by FD Pilot View Post
Tom,

Some say rudder is advantageous in tight strong thermals and slow speed flaps down roll initiation. Oleg, stated he flew a ruderless Taboo and didn't like it, but didn't mention any performance negatives other than odd/different handling that you have to get used to and play with aileron differential to tune-out. Did you use aileron differential?
I don't use significantly different differential than I did on ruddered airplanes. Yes, you have to fly a bit differently here and there, but after a week or two you hardly notice it.

Flaps down I have 100% differential programmed... IE only up deflection and turning isn't much of an issue.
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Old Sep 14, 2011, 12:46 PM
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I learnt as a newby on a rudderless, just what is a rudder please ?
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Old Sep 14, 2011, 01:21 PM
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A rudder makes a plane more fun to fly IMO. This past summer I got into some super strong thermals down low and had my glider hooked so tight I know it couldnt of happened without my rudder. Im sure I could have been flatter and much more efficient but Im into this for kicks as well and the darn thing was super cool to see literary climbing like crazy in about a 10 ft radius
Concerning performance. I believe rudderless has a advantage for launch ,sink rate but down low [below 30 ft] rudders rule.
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Old Sep 14, 2011, 01:49 PM
G_T
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Also rudders are useful for landing and when playing tag with trees. I've handed planes with rudders to people and had them be amazed by the launch height. It is how you set it up.

I'm solidly in the rudder camp.

I rarely need a lighter plane.

Gerald

PS - I'd suggest flying helo a bit for those who lack good control of their left thumbs.
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Old Sep 14, 2011, 02:30 PM
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I love my rudder to pieces!

Earlier this summer, I broke my pull/pull rudder connection. I decided to try flying rudderless for a couple of weeks, partly to check it out, and partly because i did not have the time to do the repair. I simply taped it up, and tossed it. I belive i might have gained a few extra feet on the launch, but flying without rudder really lessened the flying pleasure imo.
The joy of making a perfect coordinated turn is such a big part of my passion for
unmotored aviation, so mayby I don`t need that extra axis, but I love it, and will never, ever again part with it.
I don`t compete (yet), but I fly alot, and i want my plane to look good in the air. Nice coordinated turns makes it look good, and that makes me happy.
Rudder makes me happy.
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