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Old Feb 18, 2012, 10:59 PM
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carbondale il
Joined Jan 2007
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Would the stab/rudder unit work as a DT if the front of the stab pops up, instead of the rear? with the T M Scout a set up like that would solve a few problems.

Kev
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Old Feb 19, 2012, 05:36 PM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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A pop up front DT system at the stab would result in the model doing a couple of outside loops before settling into some oddball upside down attitude. I'd really suggest you avoid that. Far better to set it up for a rising trailing edge setup.
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Old Feb 19, 2012, 05:42 PM
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carbondale il
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Since the Scout isn't a duration model, when the DT pops, what can I expect for a descent?

Kev
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Old Feb 20, 2012, 02:53 PM
Registered User
carbondale il
Joined Jan 2007
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You guys have been so helpful, you know who you are, thanks again. The Scout will have my first DT. I have another question: Say with the DT system, the pivot point of the stab/rudder unit is only 1/4" below the straight line of the stretched rubber band which will pull the unit up when the DT pops, and the pivot point is in the middle of the stretched rubber band, which would be about 6 1/2", will the rubber band be able to pull the unit up?

Kev
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Old Feb 20, 2012, 03:02 PM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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You want the angle of the tail to be up at somewhere between 35 to 55 degrees. Any less and it could still try to fly with a funky fast repeating stall. Any more and it will try to creep backwards and the model wants to hinge around all the time which produces funny gyrations. In between the higher the angle the faster the model will descend. A good starting angle is 45degrees.

I'm having trouble visualizing what you're describing. Can you post up a picture of the plans showing just the side view of the rear of the fuselage with the tail surfaces shown? And maybe pencil in the modifications for DT that you're considering?
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Old Feb 20, 2012, 03:12 PM
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carbondale il
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Bruce, My camera is needing batteries so I can't post a picture. My question again: the rubber band is only 1/4" above the pivot hinge. The pivot hinge is in the middle of the rubber band. Will the rubber band be able to pull the stab/rudder unit up so close to the pivot hinge? If this still doesn't help I'll be able to post a diagram next month. My design uses an aluminum tube so I don't foresee any friction.

Kev
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Old Feb 20, 2012, 08:01 PM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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Your mention of an aluminium tube suggest to me that you've decided to make the stabilizer halves slip onto a hinge pivot wire. Is that right? And then the DT rubber is pulling forward on a hook which is holding the band about a 1/4 inch higher than the pivot?

If this is correct then it'll work fine. That's more than enough leverage for even a small rubber band to pull the stabilizer to the needed angle.
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Old Feb 20, 2012, 08:06 PM
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carbondale il
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Yes, Close enough on the hinge, Bruce, Thanks!

Kev
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Old Feb 22, 2012, 01:02 PM
AZ thermal junkie
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United States, AZ, Cave Creek
Joined Jun 2011
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Smoothie Run Time

Does anyone know the practical upper limit for the Smoothie Mk3? I'm not sure how long these will run for.

Thanks in advance.

Terrill
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Old Feb 22, 2012, 02:35 PM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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Had to look that up. It's just a viscous button device. So the time is entirely set by the length of the line and tension of the inline elastic element. You just wrap the line more times around the shaft of the timer.

OK, I suppose there is a limit. It would be based on the distance from the tail to the timer. You can only put that much string around the shaft.
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Old Mar 17, 2012, 10:56 PM
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Miami, Fl.
Joined Jul 2008
7 Posts
smoothie Mk3 timer


I'm trying to use a Smoothie timer on a P30. I have it set up with a pop-up stab.
I'm using a .009 spring (1-1/4 inches long) for tension. No matter how far I stretch the spring the timer never turns. The timer moves freely by hand. It seems as though the leverage on the arm is too close to the center shaft for it to turn without a ton of effort. Does the fluid need to be thinner?? Should I heat in the sunlight?

Bill
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Old Mar 17, 2012, 11:32 PM
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Miami, Fl.
Joined Jul 2008
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More Smoothie info:



After spinning it around maybe 30 times, I can get the timer to turn some.
It will start moving and then it stops before final DTing. I then increase the tension by pulling the spring much tighter and the timer remains stalled. I might add, there is only one revolution of the string during any of these tests. It stalls with about 1/2 rev. remaining and the increase in spring tension does not force it to start again.
Since I've always used fuse technology, I'm hoping someone here may know what I'm doing wrong.
Thanks again, Bill
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Old Mar 18, 2012, 12:38 AM
Zach
Illinois
Joined Feb 2004
806 Posts
I had trouble with mine doing the same thing when I first installed it. I had pushed the arm assembly on to far and it was rubbing against the main body of the timer as it turned.

I just took a small screwdriver and pulled the arm, including the spool that the thread winds on, out a little.

Zach
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Old Mar 21, 2012, 08:35 PM
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Miami, Fl.
Joined Jul 2008
7 Posts
Smoothie re-try

After wasting a lot more time by trying to get a just perfect spacing between the winding drum and the body of the timer, I've come to the conclusion that the timer design is lacking in that area. Now the thread gets caught in the minute space between the drum and timer. It's a lose lose situation. I've removed the timer and will be replacing it with something of a much better design where the drum and arm are one in the same. Sometimes you have to waste a little time and money to find out what works. The smoothie would be sure to produce a fly away. I won't take that chance. I'm ordering a button timer now. Something that it already set up from the manufacturer.
thanks for your help.
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Old Mar 21, 2012, 09:34 PM
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United Kingdom, Scotland, Fife
Joined May 1999
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Drill a hole in a piece of square brass tubing about 1/8" long. Slip it over the post on your DT and glue in place.That way your not pulling at the bottom of the post but you have a little bit of leaverage now. Position it so that its perpendicular to the direction of pull.I did it to my home made one that would stick right where it needed to pop off. Trouble is gone, works a treat.
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