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Author Topic: DT set up help  (Read 1044 times)
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Mikek
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« on: December 07, 2017, 09:40:02 PM »

Relative newbie to free flight. Building my second embryo ( modified Embryo Streak). My first embryo was kind of heavy and would do about 45 seconds consistently. Didn’t bother to put a DT on it.
Trying to build much lighter this time and want to add a DT. I’ve seen some examples for larger models with pop up stabs and wings.
What’s easiest for these smaller models? Anybody have photos of their DT set ups they can share?
Thanks for the help.
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lincoln
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« Reply #1 on: December 08, 2017, 04:54:42 AM »

I don't know if it would work on an embryo, but I on catapult launch gliders, I used to use a tab at the front that stuck out to one side and induced a spiral dive.  You can see such a tab at the bottom of this page:
https://amaglider.com/?p=view&a=dethermalizer-article
I used homemade viscous timers made with silly putty, though you have to account for the temperature. One was a pin dragged through a trough, as seen in the page above. Another used a tube in a tube. I think this kind is easier. If you use tubes that fit tightly, you can use damping grease instead. My intuition says that these will be more consistent, and perhaps there's some kind of damping grease that's less affected by temperature. I haven't tried that yet, though, only tubes that are fairly loose, with silly putty.
http://www.gregorie.org/freeflight/silly_dt/index.html

I'm wondering, with something like an embryo, if you couldn't just use a lot of rudder and get a spiral dive, using the freewheeling prop as a brake to prevent things from being too extreme. The P-30 guys use a pop off wing retained by a thin line. And, of course, there's the traditional pop  up stab.

Having once helped proxy fly for Chet Bukowski at the FAC Nats, I can attest that a good embryo really needs a good DT. Three maxes and then we lost it in the corn before the fly off.
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FLYACE1946
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« Reply #2 on: December 08, 2017, 12:37:41 PM »

Look over at the Bad Axe in the embryo section and how it was  built for the wing to release for it to  dt. This is a well designed bird and wing pop off to let it down .
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DerekMc
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« Reply #3 on: December 08, 2017, 01:51:36 PM »

Check out Maxout's video on DT.  He describes an embry pop off wing DT at the 3:30 mark.

https://youtu.be/LL85oy1NwQc

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Derek
Mikek
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« Reply #4 on: December 08, 2017, 08:20:13 PM »

Thanks for the suggestions. What about an example for a set up on an embryo for a pop off wing with a button timer?
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FLYACE1946
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« Reply #5 on: December 09, 2017, 01:38:42 PM »

Look for the  Go Devil video where Thomas Hallman flies his with a wing pop up from the front of the wing lifting up you will see why it is better to keep the wing attached . It really is worth looking for his video. Hope you can see this video.
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Mikek
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« Reply #6 on: December 10, 2017, 12:11:46 AM »

Thanks! I did see the video. His pop up wing DT works well. I can see he is using a rotary damper but can’t really see how he set it up. I figured out a way to do it this afternoon and will post pics when I get further along in the build.
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Sky9pilot
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« Reply #7 on: July 07, 2018, 02:10:45 PM »

Here's a link to the video for those who haven't found it yet: Click Here for Go Devil video
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steveneill
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« Reply #8 on: May 10, 2019, 11:20:20 AM »

I have been using these from Volare. Easy to setup and reliable.

https://volareproducts.com/index.php?main_page=product_info&cPath=1_36&products_id=1120
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steveneill
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« Reply #9 on: May 10, 2019, 11:23:27 AM »

This was my first attempt at setting up a DT. I have since improved it but it shows the basics clearly.

https://vimeo.com/manage/328896327/general
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steveneill
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« Reply #10 on: May 10, 2019, 01:28:25 PM »

https://vimeo.com/328896327  Could edit the last post this is the correct link to the Wanderer DT setup.
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Ashu
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« Reply #11 on: November 02, 2019, 12:34:45 AM »

if you use tubes that fit tightly, you can use damping grease instead. My intuition says that these will be more consistent, and perhaps there's some kind of damping grease that's less affected by temperature. I haven't tried that yet, though, only tubes that are fairly loose, with silly putty.
http://www.gregorie.org/freeflight/silly_dt/index.html

Saw this nice thread. I am still at beginner level in FF. The damping grease idea seems good. Has anyone given it a try yet? I guess it will eliminate the need for making the holes and fishing line bearings, and simplify construction greatly? Just the 2 tubes (consecutive OD size from KS Metals), the band anchor, sealed ends and grease on the inner tube. I havent used KS metals tubes but will the consecutive OD tubings be appropriate for the damping grease DT or a tighter fit will be needed?

I was wondering if I could make a small version to use on small models like Blue Ridge Special and Sky Bunny (just to learn). I intend to also try it for water rockets parachute release mechanism. https://youtu.be/fzENlikA-OM

So if I get say 1/8" and 3/32" OD alum tubes, will that be ok? Or should I go one size up 5/32" and 1/8"?
Thanks!
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lincoln
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« Reply #12 on: November 02, 2019, 01:44:56 PM »

You can also use two tubes that have a bigger gap with Silly Putty. I haven't tried a DT with damping grease, so I don't know which viscosity to recommend. I have tried two tubes with Silly Putty, though I don't remember the sizes. Also a DT that dragged a wire sideways in a trough filled with Silly Putty. Both worked fine.
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Ashu
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« Reply #13 on: November 03, 2019, 01:55:28 AM »

The 2 tubes in silly putty will be the same design as in the article? What are the holes 1 and 2 (at 90deg) for?
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