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Old Nov 13, 2012, 03:34 AM
F3B
satinet's Avatar
Warwickshire, England
Joined Sep 2006
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Quote:
Originally Posted by ScotY View Post
Where do you guys get those hollow pushrods?
can you run a bit of thick cyano down it?

What I have done in the past is to clamp the pushrod to the fuselage by attaching rare earth magnets on the outside, which causes the metal pushrod to clamp to the fuselage, so it will glue better.

the problem might come if the glue wicks in to the end of the tube, but I think you should be okay, if you use keep the fuse pointing down - the glue won't flown up. you have to make sure the metal rod is wholly within the outer tube though.

If your pushrod is not a magnetic metal that you can insert a bit of piano wire instead.

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Last edited by satinet; Nov 13, 2012 at 03:50 AM.
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Old Nov 13, 2012, 06:07 AM
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Ib Jensen's Avatar
Forest Lake, Minnesota
Joined Apr 2003
543 Posts
Thanks for the suggestions.
I have used the thread through the hole method on long booms with good results. I have also used EPP plugs in the boom on slopers and it worked very well. I carved the plug to shape with notches for push rods and holes for ballast tube but I did not glue the plug in place, I let the friction fit hold it in so I could remove when needed. Its been working for years on my old Fun 1.
I think I will try the magnet approach to insure good placement andl use gorilla glue mixed with a trace of water to get it foaming. If I place it in in the end of a tube and injecting it points along the push rod I should get good results.

I nth past I have used a small light bulb on the end of a stick pushed down the boom so can see the shadow of the push rod through the boom for proper placement of the holes for the string tie down method. I have seen flexible shaft bore scopes and a YouTube video of how to make your own. Anyone ever tried this?
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Old Nov 13, 2012, 06:29 AM
Ricky Windsock
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USA, FL, Sanford
Joined Nov 2008
1,585 Posts
Quote:
Originally Posted by ScotY View Post
Where do you guys get those hollow pushrods?
Lots of manufacturers. Search for Hypo tube. You want 18g or .050" outside dia .030"id in 304 SS at 60" long.
Amazon Supply -Part Number - h0050010t304who 5' http://www.amazonsupply.com/dp/B0013...sp_dp_g2c_asin
$9.27
Component Supply with HTX-18R x 60in
http://www.componentsupplycompany.co...FQf0nAodtEQAVQ
.050"od and .030"id
OR MicroGroup with 304H18H
http://www.microgroup.com/Products/S...mic_tubing.asp
Have fun shopping
Gordon
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Old Nov 13, 2012, 07:02 AM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
21,425 Posts
Quote:
Originally Posted by ScotY View Post
Where do you guys get those hollow pushrods?
You don't really need a hollow pushrod to attach a music wire L to the end.
I just used a piece of aluminum 1/16" id tubing about 40mm long and have 20mm of pushrod and 20mm of music wire inserted into it.
Use JB weld or rubberized CA to glue it after roughing up the parts and then cleaning them with acetone or alcohol...

Or, you can overlap the pushrod and music wire, rough both pieces up, clean, and use shrink tube over the overlap, and wick in thin CA from both ends.

The last method may sound scary, but test it out on some scraps, and try to pull them apart....

R,
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Old Nov 13, 2012, 05:14 PM
Registered User
Niagara Falls, Ontario, Canada
Joined Jun 2002
64 Posts
Here are a couple of animations that some might find interesting.

In the first illustration, the pushrod is connected to where the center of the ball link would be, while the second is of my setup which provides a more symmetrical movement. These are close approximations.

I have ignored the mechanical limits of using the ball link in the manner that it is used in the Xplorer.
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Old Nov 13, 2012, 08:32 PM
Detail Freak
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Harbor City, CA
Joined Oct 2003
21,425 Posts
Love the GIF files with the moving parts!

R,
Target
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Old Nov 13, 2012, 09:00 PM
Some people call me Maurice
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Thousand Oaks, CA
Joined Mar 2004
2,547 Posts
That's some fancy CAD'ing Mike. What's interesting here is that according to your measurements of the factory rudder horn a servo deflection of +/-50deg produces a rudder deflection of 33deg/46deg -- a significant difference. Of course you could do a lot of math and offset your servo arm to compensate for most of that asymmetry but it's a lot easier and better to just install a proper horn as you did. Speaking of asymmetry, the slight asymmetry in your "correct" gif is due to the short pushrod, which in reality is infinitely long.

Another drawback of the stupid ball link (there are an infinite number) is that it allows the pushrod to buckle in any direction whereas a clevis, or even a L-bend fully constrains and supports the pushrod in all axes except one. This is likely a contributor to the loose pushrod issue brought up by Jensen. By the way, what I do to fix them is bend the rudder 90deg, look inside with a small keychain flashlight, use a long stick to smear a drop of Gorilla glue near the right spot, wiggle the pushrod to smear accordingly, spray a little water, reconnect pushrod and dry centered. It's harder than it sounds and you'll surely poke your eye out.
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Old Nov 13, 2012, 09:47 PM
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Niagara Falls, Ontario, Canada
Joined Jun 2002
64 Posts
I used a program called C.a.R. aka Compass and Ruler. It's not the easiest piece of software to master, but I managed to learn enough to create these "constructions" as they are called. The animations were created by cropping and assembling screen saves.
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Old Dec 01, 2012, 06:04 PM
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Ib Jensen's Avatar
Forest Lake, Minnesota
Joined Apr 2003
543 Posts
I have finally gotten around to fixing my loose rudder push rod. I was wrong as to where the sleeve pulled loose. It was not at the tail but at the wing saddle. I made a light on a stick I could run down the ballast saddle and found that the sleeve was loose where it loops over the ballast bar end loop just behind the trailing edge of the wing saddle.

It was easy to dab polyurethane glue along the sleeve to hold it in place.
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Old Dec 13, 2012, 06:34 PM
Registered User
United States, NM, Albuquerque
Joined Aug 2008
371 Posts
Guys

can anyone advise a safe starting CG for a X 4.0 V-tail?

Cheers

Marco
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Old Dec 13, 2012, 07:02 PM
Win=span\massXpractice+lu ck
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Joined Jul 2007
2,936 Posts
Quote:
Originally Posted by virtus View Post
guys

can anyone advise a safe starting cg for a x 4.0 v-tail?

Cheers

marco
120
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Old Dec 13, 2012, 08:43 PM
Sean Worthington
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Campbell, CA
Joined Sep 2004
238 Posts
Hi Marco,

I have a 4M V tail and 4M X tail. I run the V at 113 and the X at 120. I was running the V farther aft to get weight out of the nose but noticed the launch was suffering due to down trim, was harder to thermal smoothly and then did a dive test and saw a pretty pronounced tuck. I then put weight back in to get it to 113 and live with my 69oz "pig". The X tail was very tolerant of CG (running aft of 125 for a while) but the V started to not behave for me about 7mm farther forward.

Sean
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Old Dec 16, 2012, 01:06 PM
Registered User
xplorer F3J's Avatar
Belgium, Vlaams Gewest, Aalst
Joined Sep 2011
18 Posts
Xplorer X-tail

Hi i fly my xplorer 4m X-tail cg on 110 mm and use a lot of camber winy condition or without wind

And whit this settings have i won two stage's in the Belgian F3J league this year

Greetzz
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Old Dec 17, 2012, 12:15 AM
registered user
Australia, QLD, Gold Coast
Joined Sep 2008
2,443 Posts
A little video of 3.8 Xplorer...

explorer sunday F3J supra & Vulture (5 min 9 sec)
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Old Dec 17, 2012, 01:31 AM
Thermal Wrangler
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Launceston Tasmania
Joined Mar 2004
2,080 Posts
Great stuff. Love the 4-legged line retriever. Where's your amazing field? Bris?
Chris.
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