Vintage Propellers

[Paul Jefferies]

Following on from my question about the strength of the glue on old models, I started the refurbishment today with the engine and started that by removing the propeller.... Over the years I tried quite a lot of propellers in an effort to find which gave the best performance/noise combination. The particular prop in question is an MK Glass prop which I think is some kind of glass reinforced nylon and I have several of these as well as the more usual grey glass/nylon props and many wooden props. Most of these are between 25 - 30 years old and like the model, have been stored in the loft for much of that time experiencing the usual extremes of temperature that happen in your average loft.

Has anybody used such old propellers? Will they be safe to use?

Edited By Paul Jefferies on 27/12/2013 22:56:07

[IanN]

Don't know about your "MK glass" prop

I've recently run some 40+ year old props on their original diesels without any problems. Top Flite and KK, I think (nylon, maybe?) and I seem to remember we boiled them in water before using

The extremes of temperature they experienced back then when stored in garages/sheds were no different to the temps you mention now - although (obviously) being "aged" they have been through far many winters than newer items

Like any other prop - new or old - I wouldn't stand in front of or to the side of it when running. That said, its a relatively low cost item and as you don't know the history - how many times the prop has been crashed, and therefore weakened, e.g. - there seems no good reason at all not to err on the side of caution and buy a new one

Edited By IanN on 28/12/2013 00:33:21

[Dave Miller]

I wouldn't use them either and I think that you will find that modern designs are more efficient.

[Matt Jones]

As above I'd bin it and buy a new one. It could have gone brittle with age or developed cracks you can't see. If it comes apart on the ground there could be an injury, in the air it could shake the nose off the plane. A few quid buys peace of mind.

[Steve Hargreaves - Moderator]

I remember the old MK Glass props.....very stiff & very good as I recall.....

Would I use such an old one.....? Not a chance....most plastics become embrittled with age & the risk of it failing is, to me, far too high. Put it on the workshop wall & look at it but don't let it near an engine.

I'm sure you will find that modern props are more efficient anyway.....I'm very much liking the JXF props from GS & HK at the moment.....great sport props & cheap as a very cheap thing....

[Paul Jefferies]

Thanks everybody for taking the time to reply........ I was afraid you might say that but I thought there was no harm in asking....... I was kinda hoping that somebody might have already done the same thing and found it to be OK. As you said Steve, MK were very good props and I have several of them but the risk is just too great.

I also have some of the really lovely OPS wooden props (12x6). They seem fine and I think it should be safe enough to use them...... provided of course that they haven't got woodworm! Or do people think I should chuck them too?  I will have a look at the XJF etc that you suggest.

 

Paul

Edited By Paul Jefferies on 28/12/2013 14:08:32

Edited By Paul Jefferies on 28/12/2013 14:10:15

Edited By Paul Jefferies on 28/12/2013 14:11:15

["L"Plate]

I am with a the majority when it comes to the fibre glass prop’s as the take on water into the resin and this causes micro fractures with temp’ changes, also the resin becomes harder which makes it brittle.

Now the wood prop’s I would use but only if: they balance, they haven’t split or more importantly warped. I have some 40+ year old wooden prop’s that I use on my CL models but I don’t rev the engine to the max. Mind you as IanN said “I wouldn't stand in front of or to the side of it when running.”

[Shaunie]

I used MK props, there are undoubtedly more efficient props available but I had one on an OS 45FSR in a High boy trainer. It was the only prop the engine has ever had on it despite many learning to fly on the plane. Numerous rough landings, nose overs, whatever you can throw at its and no-one ever broke it. As one of the toughest props I've come across they may be OK to use.

Shaunie.

[john stones 1 - Moderator]

M.K. used to be best prop on market, as long as they have been stored out of frost and sunlight they should be ok

I still have a few which are as good as new. A.P.C. props are good and graupner still do a good prop both nice and stiff.