RC India

If you don't have access of push rods, this can be used as alternative  ;D
while making my SPAD in my home town, i couldn't get it as there is no hobby shop yet..

Dedicated to all those who doesn't have access to hobby shop in their home town. :thumbsup:

Better still - use a piece of string - and tension it on the other side with a rubber band

i.e do not use a push rod at all

the best push rods cost me about Rs 2 per piece... they are the normal cycle spokes...... They are easily available and also very cheep to buy....

@ Shobhit & Saikat

There are many alternatives .. its just one of them..  ;D

Agree with Shobhit sir. Cycle spokes are the most easy to get and also very cheap. Also, these have sufficient strength and could be easily bend to any shape with help of pliers.

Bamboo cocktail skewers...................Dirt cheap! They can work out to less than a Rupee per piece. All that you have to do is make two z bends with wire, wrap them in string and cyano them to both ends.

http://www.ebay.in/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xbamboo+skewers&_nkw=bamboo+skewers&_sacat=0&_from=R40 (http://www.ebay.in/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xbamboo+skewers&_nkw=bamboo+skewers&_sacat=0&_from=R40)

Yes yes the same bamboo skewers, ill post pick in hours about how i made them, it was described in a PDF that sanjay sir gave me.
Stiffer than iron wire, lighter than spokes. Used normal polyester thread and fevicol. Ca doesnt go good with wood.

Ashok.P

Go ahead Ashok, I won't steal your thunder.

pics. Ive seen people in sholavaram using them on even nitros.

bamboo skewers for 58 rs. 100pcs from royal plastics Luz Chennai

For longer pushrods, use
phool jhaadu ki teeli
 ;D

bro yeh jo jhadoo ki tilli k akhir mai lagaya hai.. {:)} {:)}...what do we say it. :help: :help:..actually im new to this hobby :-\ :-\

Have you guys ever though of using the ones in electric sparkles ? Comes in various length. Although you need to use it before lighting it. If you want to use the full length, then take one full length sparkles, keep it outdoor on a hard and flat surface and gently hammer the Actual Chemicals out. I use this method because so many are left excess in home Diwali after Diwali.

The hammered out chemicals ones can be used to make a custom torch cracker ;D

http://anilfireworksonline.com/productdetail.php?productid=20-50-CM--ELETRIC-SPARKLES

they are a bit soft ( Sparkle )post you use them.....
1. once using them when red hot put them in water this will harden them and will not easily bend.

Saurabh - have you actually tried this?

(http://media.web.britannica.com/eb-media/42/1542-004-6E542B14.gif)

If you suddenly cool that wire rod, because of the very low Carbon percentage it will hardly harden. It needs about C45 to be effective  ;D

@Saurabh - Quenching does help. But easier option is to look for sparkles from different manufacturer and different variety. Each has different property.

Another alternate of push rod is using pull pull system... not easy for a first timer..  but must try it,  Works great if you set up properly.. & very light weight also.

What you use for giving tension in pull pull mechanism??
Send pics of other end..

We can also use empty ball pen refills connected together. I have used it in one of my plane but still waiting for its maiden flight.

A 'pull pull' mechanism has two sided servo arms as in sharlock's pics, and control horn on both sides of the control surface. Instead of a 'push/pull' rod, you have one 'pull' rod, ie, cable or thread, on each side. So when you give 'up', one thread pulls, and when you give down, the other thread pulls.

The difficult part is getting the lengths and tension equal on both sides.

You can even have a mechanism with a single pull thread!
For details you can see my RCTLG thread...

Edit: Reply 19-21 in this thread

www.rcindia.org/kites-trains-free-flight-and-all-others/sweepstakes-rctlg-k-k-iyer/msg183753/#msg183753

A lot of expensive equipment goes inside an aeromodel. If not properly managed, it is also a dangerous flying hazard.

It amazes me how anyone could want to screw around with a lowlife item like a pushrod.

Do not try to emulate Iyer sir - unless you too have 50+ years aeromodelling experience under your belt

@ sanjay sir,

I have done this and seen good % age of hardening (at least you can feel). When the sparkel is burning the temperature is quite high quenching at that time will be much more effective.

Temperature while burning is high as in some cases the wire melts and drops.

regds
Saurabh
 

Irresponsible statement from someone as experienced as yourself!

You know sparkler rod steel has NO standardization. You will never get consistent results. And you are encouraging others to adopt risky methods which can lead to a catastrophic failure or a serious accident  :violent:

Sir,

1. These are suggestions. the decision to use / not use is solely @ discretion of the user.
2. The model in talk is not a 10000/- model we are talking of small foamy model.
3. If a simple Jhadu ki tilli can work a sparkel metal rod can be used with wonderful results.
4. I am responsible enough to suggest only the ideas which are used and implemented by myself.
I used the sparkle wire on pop wing as push rods and i found good enough hardening on that wire post quenching.

Scratch building is all about ideas.... some may be too good and some may only be good.

If you go for ideal solutions which are mostly expensive ( and not available locally) the budget will exceed or the AUW will exceed.

Cycle spokes are much heavier than sparkle wire.

regds
Saurabh

Guys, IMHO, experimenting doesn’t need experience. On contrary, it is those very experiments which builds up experience.

Saurabh, please note I really meant no offence. If taken, I humbly apologise.

The fact is many newcomers do ask their queries, and sometimes without thinking the whole matter through, blindly follow that advice, irrespective of how qualified it is.

Sure, use a sparkler wire....... but what length can you safely use?

I continue this explanation in the next post........

In continuation, an aeromodel is a potential hazard. Experimenting is indeed very well, for you learn, but when you are dealing with a hazardous object and/or activity, you never go blindly into it. Not at the risk of injuring anyone; nor at the risk of losing/damaging your equipment.

Take the case of a low cost foamie. The modeller has used a 1 mm sparkler wire as the elevator pushrod with a length of 8 inches. In flight it deforms permanently leaving the elevator in the down position. The model weighing (All Up) 500 grams comes diving down at a speed of 40 mph.

This is enough to

a) Injure someone
b) Destroy the battery, motor, Rx, servos plus model. A loss of thousands!

And for what? Saving Rs. 5 on a cycle spoke?

Go ahead and experiment: there can be no development without it. But, understand in depth the science and practise of what you are doing, and carry the responsibility of the same. Irresponsible acts give the whole community a bad name. Use other's experience as your textbook.

The hobby has enough risks as it is; we should try to systematically and scientifically reduce these to the maximum extent possible. I too have been guilty in my time of taking unnecessary risks, and now do try to eliminate these, as should all of us.

+1 to that.
In today's age, we should use CF rods as far as possible, with an adjuster at the servo, and a support in the middle.
Using jhadoo ki teeli etc is a hangover from the days of scrounging for alternative as stuff like Goldenrods, clevises etc were either not easily available, or we could not afford them.
Cycle spokes are, in my opinion, unnecessarily heavy and too thick to fit the servo/control horn.
Traditional pushrods used to be balsa with wire ends, but do not use unless it is is really hard/stiff balsa, and is not less than 1/4" sq. (I know from recent personal experience that a 1/8" sq will flex and ultimately break even in a foamy)
What Rai saheb says is doubly important as i see many modellers building HUGE control surfaces, imitating 3d designs.
Two other avoidables:
1. Aileron pushrods angled out significantly from a single servo
2. V bends in wire pushrods to allow adjustments

BTW, the single thread method i used is intended for lightweight, slow gliders. Mine is 200gms and flies at 5-6m/s (~20kmph). It is actually a specialist method, not intended for regular powered models including foamies.

A simple test.
If you can move the control surface by hand without the servo turning, the pushrod is inadequate!

@Sanjayrai55, no body is contesting that people are trying to save a couple of bucks and you jumping to conclusion that people are irresponsible is not appreciated  :(.  One has to employ all necessary precautions and testing needs to be done in a place where even such mishaps doesn't endanger others. That is common sense right ? Not sure how that is going to endanger people  :headscratch:

GP Freak: I'm sorry but I do not think your post is worthy of a reply

Iyer sir, well said.

Flexible outer/inner pushrods (snakes) are an excellent option for longer lengths. But the ones with an inner plastic tube-rod are useless. The ones with a 1 to 1.2 mm inner wire rod are excellent up to a 40 size model. Just make sure it has adequate support and anchoring of the outer at frequent intervals - like every 100 mm or so. That way, effectively the unsupported length is never more than 100 mm.

Remember. buckling (the cause of failure here) is a function of the length. If you will notice large models usually have the empennage servos fitted in the tail, with push rods less than 3" long. I prefer (where possible) to fit the elevator & rudder servos in the tail section with short pushrods even on smaller models. I say "where possible" because of CG constraints in design.

On cycle spokes, you get 2 mm spokes, which fit (threading included) into standard clevises and linkage stoppers, and are good for up to 4" with standard Servos or 6 Kg-cm torque. I normally use them for ailerons.

Flexible inner/outer pushrod

(http://s25.postimg.org/7z9t0ddxb/20141208_102713.jpg)

Rear mounted Servos (17 gram)

(http://s25.postimg.org/6b5j1cgxr/P1030038.jpg)

Need to properly glue the outer at all contact points to prevent bending/buckling

(http://s25.postimg.org/xlyggkhq7/20150305_093155.jpg)

Rear mounted standard servos

(http://s25.postimg.org/c85e4jqyn/20150226_150740_1.jpg)

Cycle Spoke (2 mm) as Aileron PushRod

(http://s25.postimg.org/goi6a35q7/P1030235.jpg)

Reading some of the previous post from some people...  I would only say going for an alternative is only perfect if its well proven over the time, its not a question weather you are flying a electric or a engine powered airplane, talking about model airplanes these are not toys & over the years I have seen many disasters here in India, why not simply use a CF rod..  which can cost just Rs. 100/-

The cycle spokes are well proven & are used worldwide since many years... especially all my engine airplanes for 0.15 & above I have used them & never had issues with it  :hatsoff:

Carbon Fibre rods are nice. The only problem I face is with 3 mm rods or higher, the end fastenings is an issue. A clevis normally is good for M2 threads, and Linkage Stoppers too take 2 mm dia rods.

So I use a CF tube, 3 mm OD & 2 mm ID and glue metal rods inside. In the photo below I have glued a 2 mm Cycle spoke about 60 mm long into the CF Tube

(http://s25.postimg.org/q8qqocw5b/IMG_20150521_102131_HDR.jpg)

I would be happy to know what others do for this

Personally, I have used only cycle spokes on all my builds (on Sanjay Sir's advise). They are pretty stiff and fit easily into the linkage stoppers. Never faced a problem with them. However, I have heard of people using piano wire (available at music shops) successfully. Never tried them myself though.