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Wood dowel push rods

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Old 03-22-2006, 10:33 AM
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mobflier
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Default Wood dowel push rods

What is the advantage or dis-advantage to using wooden dowels for push rods? I built a Stinger .10 that shows them in the plans, but I used steel push rods with no problem. Any ideas why?
Thanks
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Old 03-22-2006, 10:44 AM
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2slow2matter
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Default RE: Wood dowel push rods

Less chance for RF interference. On long spans, there is less flex than with steel rods--unless you've braced the rods tube into the formers along the way--then you should be fine. On long spans anymore, I just use either the dave brown fiberglass jobs, or carbon fiber, or even the sulliven golden rods, as long as they are braced and supported properly.
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Old 03-22-2006, 10:45 AM
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RCKen
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Default RE: Wood dowel push rods

What 2slow2matter said!!!

Ken
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Old 03-22-2006, 12:01 PM
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Gringo Flyer
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Default RE: Wood dowel push rods

The dowel setup to me is a little sloppy. Its OK for a trainer but I wouldnt use them on anything else.

Something like these http://www2.towerhobbies.com/cgi-bin...?&I=LXD856&P=7 is much better. They are easy to install and to me are a lot more practical. You have to brace them every few inches but they give you a little flexibility in case its not exactly a straight shot from the control horn to the servo.

As far as the steel rods just make sure they are heavy enough and wont flex under load. I would think that a 2 56 rod would be fine on a 10 size shrike as long as it is not too long.
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Old 03-22-2006, 03:48 PM
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Default RE: Wood dowel push rods

the best alternitive I've found is DAVE BROWNS fiberglass[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXB901&P=ML]pushrods[/link] push rods. It has the little to no flex and no interferance of the wood dowl with no slop issues
just get the right sized wire and fit em in with a 90 degree bend
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Old 03-22-2006, 04:41 PM
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Default RE: Wood dowel push rods

In general, I believe push rods should be as short as possible, like just a few inches. The ideal push rod doesn't flex or stretch and is perfectly rigid (cannot bow) and is very light. Wood is cheap, but is far from meeting these criteria. Short rods often cannot be done with elevator and rudder. Rudder is generally easy to setup as pull/pull, which eliminates the push rod issue and offers a light weight solution with better positive control. Elevator on many sport planes does not lend itself to using short push rods. My first suggestion is to use carbon fiber rods/tubes being from a pattern background. They aren't terribly expensive, but may be overkill in some sport models. You can find them here… http://www.centralhobbies.com/contro...e/carbrod.html As my second suggestion, the glass rods RedFox mentioned are superior to wood in their physical properties, install similar to the wood rods, and aren't expensive. As a last resort, the wood rods will work, but they aren’t ideal. Cheers.
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Old 03-22-2006, 10:19 PM
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Default RE: Wood dowel push rods

Dave Brown fiberglass rods work fine-but carbon/graphite arrow shafts make excellent pushrods-archery shops have a variety of diameters and price is usually about $2-3 for 36" shaft. The aluminum inserts for broadheads work just right for epoxying in 4-40 or 2-56 rod ends. Much lighter than wood dowels and easier to work with.
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Old 03-22-2006, 10:45 PM
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Default RE: Wood dowel push rods

I haven't used fiberglass or CF rods yet, but I did retrofit a nice pattern plane (CA Models Widebody) to dowel pushrods and it tracks straight and nice. If there was slop or play, I would see it right away. They can be sloppy but they can also be pretty good too. The Widebody fuselage formers all had holes cut for rods, so the dowels slid right in and has very good support. I can't see any slop anywhere. I guess that you can get flexing if you don't have some sort of guide for them down a long run but I don't see how they can flex or have play if you support them. I trust the gluing, drilling, and CA thread on dowels more than I do on CF or fiberglass.


War Eagle to you, Gringo.....
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Old 03-23-2006, 04:32 PM
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Default RE: Wood dowel push rods

I use dowel rods in a couple models, Pica T28 and Stafford Ercoupe. They work great. I think they have less slop then Nyrods and they cost less then the carbon fiber or fiberglass rods. And because they are wood, they expand and shrink the same as the airframe. So my trims don't change from winter to summer. Its a little tricky trying to get a straight shot from the servo to the control horn sometimes. But a properly installed rod is just about as slop-free as it gets. Try to avoid a "Z" bend in the wire end when exiting the fuselage. The "Z" bend WILL be a source of slop as it will flex at that point. If at all possible, use a straight wire at the end. And try to use the minimum amount of wire at the end. A long wire will flex. So, with all of these limitations, they will not work in all models. But they are my first choice if the airplane design allows for these limitations. And these limitations apply to carbon or fiberglass rods as well.
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