Central Hobbies pushrods

[KRProton]

Found a forgotten box of pushrods and pushrod ends in the corner of my basement today. I'm still not settled on what pushrods and pushrod ends to use, but here are my notes from this stuff:

As shown in the photo from top to bottom:

CHMROD35 .125” (1/8”) O.D., 35”
(Use with CHMPRE35 series ends)
I could not find CHMPRE35 ends on Central Hobbie’s web site, but 2-56” pushrods (.074” wire) fit inside these rods perfectly. I use a reinforced cutoff wheel to cut several notches in the pushrod, then roughen with sandpaper and glue into the rod with epoxy. Typically used for rudder on a Q40 airplane.

CHMROD24 .156” (5/32”) O.D., 24”
(Use CHMPRE24T2 (2-56 thread) or CHMPRE24T4 (4-40 thread) series titanium pushrod ends)
Typically used on ruddervators on V-tail Q500s. Also good for Q40 elevator? I use the 2-56 ends. Some may use 4-40 on a Q40.

CHMROD36 .187” (3/16”) O.D., 36”
(Use CHMPRE36T4 (4-40) or CHMPRE36T8 (8-32) titanium pushrod ends)
Probably good for elevator on a Q-40 if you are okay with 4-40 hardware.

Note: I usually like to "sleeve down" 5/32" tubes or 3/16" tubes with 1/8" tubes so typical pushrods can be used inside the 1/8" (for elevator on a Q40), but this 1/8" does not fit inside this 5/32" or inside the 3/16".

CHMROD38 .210” (approx. ¼”) O.D., 38”
(Use with CHMPRE38T4 4-40 titanium pushrod ends)
Probably too large for use in typical 3-pole AMA pylon racers.

https://www.centralhobbies.com/cat4.php ... sub2cat=44
https://www.centralhobbies.com/cat4.php ... ub2cat=123

Tim Lampe

[Dave Yost]

for what its worth, I use central hobbies push rod ends on all of my electric 3D ARFs, Love them.

However, a few people over the years have advised me that the titanium is brittle and at risk of failure due to vibration on a nitro powered pylon racer.

Not sure how true that is, but I have stuck with music wire for that reason.

Cheers, Dave

[KRProton]

Thanks for commenting Dave. Would be interesting to see what anybody else has to say.

Tim

[Dave Yost]

This is how I do mine (Z bend on the other end) Q40, the wire portion is shorter, these are for the Ricochet.

[KRProton]

I have some 1/8" stuff that fits inside 5/32". 2/56 fits inside the 1/8". But don't know where the heck I got it from.

Tim

[David Ford]

Hi Tim,
I get my 1/8 carbon tubes from Darrol Cady, maybe you got them there as well. For the control surface end I do the following
1. Sand the OD of the carbon tube and epoxy an aluminum tube that just fits over the carbon tube, Leave it overnight.
2. Get a 2/56 tap and tap the inside or the carbon tube. Get some 2/56 "all thread" and deepen the tapped hole to an inch or so but not past the aluminum tube.
3. Cut off about 1 3/4 inch of 2/56 "all thread" and clean it with solvent and chamfer on both ends. I use the Dremel cutoff wheel for this. Trial fit into the carbon rod to see how far it goes in.
4. When happy with the fit, use slow epoxy or IC-2000 on the "all thread" and in the carbon tube.

Epoxy is a sure thing with this method, IC 2000 I am not sure of yet as I had an end thread in and stop before I expected it to. Not sure if the glue went off (seems unlikely) or I just hit the end of the threaded part I made. More work to do on this.

On the servo , I do the same as you described above.

Dave

[rs-ssfan]

Tim,

I've been using the 5/32" rod with the 2-56 titanium tips in both Q40 and Quickie for several years now. I prefer this size, especially in Q40, because they seem to be stiffer than the 1/8" rod. It's worked well for me so far.

Thanks,
Lonnie

[Dave Yost]

Thanks for data point Lonnie,
I love those rod ends, if I know they work, I will switch!

Cheers, Dave