Cox Propellor

ian1954 wrote:Be careful.

Interesting incident today, Propellor blade sheared off while bench running my Hiscott Medallion! Can't find the blade that sheared off!

It seemed very flexible and not brittle in anyway.

It has 'Cox Hobbies Inc' on it - I have quite a few!

If those are original Cox props they may not be safe to use.

Bernie has new props at bargain prices. My favorites are the rubber ducky flexible props, and I've yet to break one.

Bill

check the ceiling......

I have a number of Top Flite propellers that are suffering the same fate. I have not tried boiling them in water yet, but simple soaking did not change the failure mode.

The nylon is supposed to absorb water improving its pliability and resilience. In fact, soaking NEW propellers does improve the durability of them. I soak nylon props overnight then keep them in a zip lock bag. The new propellers are more supple after soaking. The treatment is also supposed to be good for glass or polyester filled nylon props.

Phil

pkrankow wrote:I have a number of Top Flite propellers that are suffering the same fate. I have not tried boiling them in water yet, but simple soaking did not change the failure mode.

The nylon is supposed to absorb water improving its pliability and resilience. In fact, soaking NEW propellers does improve the durability of them. I soak nylon props overnight then keep them in a zip lock bag. The new propellers are more supple after soaking. The treatment is also supposed to be good for glass or polyester filled nylon props.

Phil

If the props absorb water wouldn't affect the balance?

Jim

ian1954 wrote:Be careful.

Interesting incident today, Propellor blade sheared off while bench running my Hiscott Medallion! Can't find the blade that sheared off!





It seemed very flexible and not brittle in anyway.

It has 'Cox Hobbies Inc' on it - I have quite a few!

Did you purchase them from us?

Cox International wrote:

ian1954 wrote:Be careful.

Interesting incident today, Propellor blade sheared off while bench running my Hiscott Medallion! Can't find the blade that sheared off!





It seemed very flexible and not brittle in anyway.

It has 'Cox Hobbies Inc' on it - I have quite a few!

Did you purchase them from us?

I did but I am not seeking any redress. Just a warning to be careful where you stand when close to a running engine.

Plastic, nylon etc. are strange materials and anything that is cast or moulded is suspect. There is no way of checking for perfection unless you have X-Ray vision. One in many hundreds of chances of this happening.

This did not hit me, I didn't even see where it went (haven't found it yet either!). In front or behind the propellor is probably the safest position. I once took a splinter in the back of my hand from a wooden propellor. I was smoking a cigarette - it could have been my jaw!

There have actually been issues with those props as they are old Cox stock.

We test-bend each one and have about 25% failure rate. Only a few hundred left and we are getting new ones moulded.

Please identify yourself to us by email to support@coxengines.ca with perhaps either an order # or order date. We will then send replacement props.

JPvelo wrote:

pkrankow wrote:I have a number of Top Flite propellers that are suffering the same fate.  I have not tried boiling them in water yet, but simple soaking did not change the failure mode.  

The nylon is supposed to absorb water improving its pliability and resilience.  In fact, soaking NEW propellers does improve the durability of them.  I soak nylon props overnight then keep them in a zip lock bag.  The new propellers are more supple after soaking.  The treatment is also supposed to be good for glass or polyester filled nylon props.

Phil

If the props absorb water wouldn't affect the balance?

Jim

In principle it will absorb water evenly, so balance should be minimally affected.

Phil

....along those same lines, an old thought/theory/belief was that wooden props should be stored horizontally as storing vertical the moisture would migrate to the bottom.

I gotta wonder if that concept came from '1:1 scale' wood props

Cox International wrote:There have actually been issues with those props as they are old Cox stock.

We test-bend each one and have about 25% failure rate. Only a few hundred left and we are getting new ones moulded.

Please identify yourself to us by email to support@coxengines.ca with perhaps either an order # or order date. We will then send replacement props.

Bernie,

I thank you for the offer and your exemplary service but these things happen and a $1.95 prop (£1.28) is of little consequence to me. You are also to be acknowledged for conceding these props lack of perfection and for testing them before you ship.

Buying "old things" is always a risk, not everything stands the test of time and things that spin at 5-30,000 revolutions per minute have to be treated with caution - new or old. It could happen with any propellor - just don't stand in line with the blades!

Thank you again.

Ian,

We really need to replace them, as we have done for others in the past, as they were evidently defective before we shipped and you can expect to receive non-defective merchandise.

We insist ... 

Haha, Ian you're gonna get new props and by dang, you're gonna like it! And that's that.

I will drop a note with my next order!

"Oh yes you will, oh no I won't" - British pantomime  sketch!