dhal22

does anybody have a preferred method of dual pushrod setup for elevators?

thx, david

dbacque

My Feedback: (3)

Take a look at the DEPS here http://www.centralhobbies.com/contro...age/deps1.html, there's also a link to a how to article.

The same thing can be done with 4-40 steel pushrods instead of the carbon. I run dual pushrods, both in a straight line and solder them together on the servo end. There's a picture of one in post 11 on this thread http://www.rcuniverse.com/forum/m_76...tm.htm#7698989

If you have good straight runs and brace the guide tubes at several points they will be frictionless and have no flex.

Dave

dhal22

well, i ordered the DEPS pushrod system from central hobbies and i was disappointed in the friction between the clear tubes and the CF rods. quite a bit of drag between them. i also found out you can't have your receiver antennae wire inside the fuse with CF pushrods. hence the search for other methods. thx, david

Deadstik

My Feedback: (8)

David,

I've used Dave Brown fiberglass pushrods that have a Y connection in them on every pattern ship I've built. As long as you mount your elevator servo where it has an absolutely straight run to the Y both elevator halves will move equally. It may take a bit of time to properly bend and align the Y.... but it is just a method I've always used and still use today.


Dan
Carolina Custom Aircraft

rainedave

My Feedback: (1)

I did what Dan does on my UFO.

Post #93: http://www.rcuniverse.com/forum/m_40...4/key_/tm.htm#

David

Atlanta 60

My Feedback: (18)

Huh?? I sure don't understand that concept...

Is there a thread on this subject??


BTW: I like the Dave Brown fiberglass shafts too...

JeffH

My Feedback: (43)

The best method I have seen was on a Sequel that Dave Guerin built back in the 90's. He used the standard arrow shaft pushrod with two 4-40 rods in a Y format. The difference was that instead of coming out of the end of the shaft, he attached the 4-40 rods to the shaft on the OUTSIDE about 4 inches from the end of the shaft. He drilled two 4-40 sized holes in in the shaft where he wanted the rods to attach, bent a short L in the rod to lock into the holes, left about 1.5 inches or so straight before he bent the Y to exist the fuse. He bound the wire to the shaft with kevlar and epoxy??? Now you ask, why??? Remember the extra 4 inches past the Y, well the went into a former that had a precisely drilled hole in to support the aft end of the pushrod. The kept the pushrod from moving up and down or side to side. Of course you still need to make sure your elevator servo is precisely mounted to eliminate the angular deviations.
I try to mount my elevator servos laying on their side when using a y set up.
This probably does not make much since in words, but I dont have a picture.

rainedave

My Feedback: (1)

Cool. That's a great idea having the end of the arrowshaft extend aft through a former. I wish I had seen this sooner.

David

8178

My Feedback: (17)

JeffH,

That looks like a good idea although I’ve found if you plan the installation well, cut the exit slots correctly and use Great Planes plastic exit guides you won’t have problems with the shaft moving. I used fiberglass arrow shafts for the rod for many years until a few years ago when I decided they were expensive overkill and started using ¼� hardwood dowel.

I tested the concept by lifting my bench vice and then decided that it might be strong enough for the control surfaces.

Atlanta 60

My Feedback: (18)

JeffH..Great Info!!

That is the same method I'm familiar with but I never thought of doing the 4/40 rods on the outside and wrapping them...That is sweet!! I struggled and finally fit 4/40 rods once (just like raindave's experience from the other thread)...I really didn't like doing that...This external method should work Great!!!

Thanks for posting!!

Chuck

Taurus Flyer

Gents,

Maybe interesting for you, my own design method to couple two elevators on the pushrod, as by my Taurus. So with central and intern connection!

Try to make a bras bearing with grease because after mounting it is not servicable animore.
This picture is taken before lowering and glueing the horizontal tailplane in position.

The Taurus do make nearly 400 flights now without problems on this detail.
Second picture Orion, about 150 flights, same linking.
These linking is used by Ed Kazmirski in the kits from Top Flite models Orion (1960) an Taurus (1963).

Cees

anuthabubba

My Feedback: (102)

Back in the '80s a local pattern flyer (Nat P.) showed me how to use plain steel rods inside 'frosty' clear plastic (common RC parts, don't remember the brand) guide tubes. These tubes came in a coil and had to be straightened by putting the rods in them and heating them in the oven for a half hour. The rods were set up like the DEPS things and soldered at the servo end.

My old Calypso has these in it and the antenna runs down the belly to the tailwheel and I've never noticed any radio trouble. I've also used the forked elevator rod/tube (wood, plastic, f/g, c/f, alum) (mostly w/rods on the outside) in many planes over the years. The bends only have to be enough to line up with the elevator horns and exit guides help control the movement. Download the Summit III plans from AztecAir to see a clean installation of the forked rod with rear guide. Again. I never had any radio problems (72mHz) with antennas inside planes with any material (c/f, alum, steel) pushrods.

Terry in LP

dhal22

taurus flyer, where do you mount your brass bearing? i like the concealed control.

david

dhal22

mike, for a while i thought the wooden dowels were a way to sell (b)arfs even cheaper. i did notice you using this method though on your blue angel. i guess it's a better method than i thought. either way, as i suspected there were plenty of people willing to chime in with there methods.

and i love hearing that people have had no issues with CF rods alongside their antennae wire inside the fuse.

david

Taurus Flyer

Hello David,

You often see, nearly always, may I say, that they use a pianowire connecting rod between the two elevator halves.
Then they make the lever, for the push-rod by solder on these connection rod. Yes do silversolder!!!!

Wrong.................

Try to realyse what's happen when the solderconnection of the lever disconnects!!!
Yes, The two halves of the elevator still have on there last meters through the air exactly the same position, nice to know but not effective!

So

Each elevator-half you have to connect with the push rod,
Each elevator half you must give its own lever, that is the only safe method. You can not let the live of your airplane let depend on one single solder connetion on the connectionrod.
But now you have to connect two levers on the same pushrod, that thrue, but that's no problem. But do use double security!!

Between the two levers you solder epoxy two side copper sheeted circuit board AND WRAP WIRE around (that's the double safety!).
The little circuit board surface on the end of the levers. Thats the place you solder a bras bearing that has a good fitting with the rod.
Remove the copper from the circuit board on the place you can see on the picture.
This is my methode to isolate (electrical) the metal of the pushrod from the elevator connectionrod!!!

You've ever see this before? No I do not think so, own design.
Go to the Thread of the Taurus of Ed Kazmirski and look for the second quiz!!!!

Cees

JeffH

My Feedback: (43)

The biggest improvement to me was the fact that there was no more twist when you grabbed one elevator in relation to each other. With the aft end unsupported, I could always twist the elevators due to the fact the rear of the pushrod was floating. With it secure, it is almost as if you are a direct servo connection, its that solid.
I have no doubt that a dowel is more than adequate. I use the graphite, fiberglass or carbon rods for weight. I am obsessive about weight, so grams make ouces, and ounces makes pounds is my theory.

Atlanta 60

My Feedback: (18)

Plus it's Cool to say you have something Carbon Fiber on your plane... [8D]

(Sorry..I'm a CF Junkie..he he)

Chuck

JeffH

My Feedback: (43)

Of course to be really cool, you need the titanium pushrod end on the servo end of things.....yeah baby!!!
I was one of thise that had the ball bearing tail wheel on my 2m Sequel. I also polished all of the MK horns and even polished the steel landing gear struts.
Oh yeah, I always took the brand new tru-turn out of the package and started sanding it so that NO machine marks would present and then polished. Naturally they all rolled on polished aluminum axles and those sweet Pro-Mag wheels, polished of course. lol

I have a set of Pro Mags for my Atlanta...woohooo
My Mach 1 and Tiger Tail will get my Kraft wheels, Armor All'd of course!!!

Atlanta 60

My Feedback: (18)

Right On Jeff!! [sm=thumbs_up.gif]

I'm that way too...I'm just not as young as I use to be and keeping things polished has become allot tougher than it once was...

Hey are these Pro Mags?? I remember the name but I thought they use to say Pro Mag on the wheels or something?? I wondered about these.. (see pic)

(Sorry for jackin' the thread David)

JeffH

My Feedback: (43)

I think they are MK wheels. The Promags that I have, have slots, kind of like the old American Racing ET slots from the 1960's that drag cars used on the rear. It is possile that they made more than one style. MK still makes theirs I think. I am pretty sure that central hobbies still has them.

Atlanta 60

My Feedback: (18)

Gotcha..Thanks..I know what your talking about now...

Yeah I figured I'd try and stock up on MK wheels (or similar..Tetra??)...Expensive but worth it...

I've been searching "Pro Mag" on ebay from time to time and come up with nothin'...Pretty sure they are out there but very scarce..

I had forgotten what they looked like..

Thanks..

Chuck

dhal22

no problem chuck. i will have to read taurus flyer's design some more, with the english pronunciation be a liitle different it takes me a few reads to understand him. but i like the idea.

david

Taurus Flyer

dhal22

Dutch english pronunciation?
Maybe the picture helps?

A good design you must look at, not read about! That's too complicated
Ask me?


Cees

jquid

Here is my new method. (2) CF pushrods from Central hobbies, and AL Control horn. both pushrods go out from servo so there is no slop or flexing. CF is pretty light so not an issue. I used the ball links so ther is no bind and they go off in either direction without hassle. Still working on the install, kids take up most building time!


http://www.rcuniverse.com/forum/m_72...tm.htm#7246813

crankpin

My Feedback: (15)

This will work fine. 4:40 rods. Dave Brown pushrod's.

Crank