Looking for lightweight folding props - any idea where to source?

[Tony Smith 7]

Hi,

 

I'm looking for a source for a light-weight folding propeller, for 3mm shaft, preferably with a range of low cost blades available in case I need to try different sizes.

 

As far as I can see, Giant Cod and others only offer either really cheap complete units which even they say aren't safe to use, or heavy-duty alloy hubs that will probably weigh more that the whole motor.

 

I must be missing something.

 

For reference the existing prop weighs 10g complete.  Unfortunately I can't just keep that one firstly because I can't find compatible blades, and also because the shaft size is only 2.3mm.

 

Thanks, Tony S

[Richard Wood]

Hi Tony,

'Gliders' stock Graupner & Aeronaut folding props.

Gliders

I haven't used these people but they seem to have been around for

a long time & are regular advertisers in the mags.

Hope this helps.

 

Cheers

 

 

[Tony Smith 7]

Cheers.   I wouldn't want to have to buy several sets of blades at those prices, to experiment.   I suppose I could start off with a "prop saver" and cheap fixed plastic prop until I was happy with the sizing.

[Erfolg]

Tony

 

The GC hubs are fine.

 

However as you believe, the blades supplied by most retailers, not only GC,  which are not Aeronauht or Graupner or similar brand name, are no necessarily good enough.

 

That is if using brushless. Even a Cf 2822 pulls about 120w, against approx. 80w max for a brushed 480.

 

Again you are correct in thinking that shedding a blade is devastating to a model.

 

It is a pity that the root of folders is not of greater cross section, so that lower UTS materials could be safely used.

[Tony Smith 7]

Thanks.   I was referring to the lightweight Giant Cod ones like this Light Complete Prop

 

"Use caution when using these props as some of them have broken. Use eye protection when using these or remove the blades onto another hub. We take No responsibilty for any injury through use of this item. Use at your own risk."

 

That doesn't give me a whole load of confidence.  The only alternative seems to be the heavy-duty allow assemblies, that will probably make my brushless conversion heavier than the old motor/prop combination!

 

The motor will be this one Towerpro 2408

 

I don't mind buying decent blades once I've got the sizing sorted out.

[Erfolg]

Tony

 

I have used the same brand from GC. As with many failures the precise details are forgotten. although I have had a number of blade failures with low cost brands.

 

These are a few of the low powered motors where failures have occurred

 

Xtra link and Max link, these are not high powered, by outrunner standards.

 

The cheaper blades are fine for brushed 480 motors though.

 

I have noted amongst ARTF models which come with GC type hubs incl. Multiplex. Their blades are better though.

 

I have never heard of or seen a hub fail, blades are a differant matter.

 

The blades where no failure has occurred are Aeronauht, Graupner and APC folders, that is after much use. I have never seen any failures of the aforementioned. Yet I have seen a small number of the cheaper Chinese blades fail on other peoples models, as well as my own. The problem is that the vibration is so sever that the motor is normally wrenched from the model

 

I have nothing against Chines stuff, as most of my electric  flight stuff is Chinese and is dam good!

 

 

[Tony Smith 7]

I guess what I'm really looking for is something like I have at the moment, but suitable for 3mm motor shaft.   Something like this   Hub for 2.3mm

 

I think I may need to go back to square one, bin the motor choice (luckily not ordered yet) and see if I can find a brushless motore with a standard 2.3mm shaft.

 

I take the point about quality, but a small glider simply doesn't need a massive machined alloy hub.   I've given the existing prop are fairly hard time learning to fly and haven't even broken a blade (touch wood) let alone had one fly off spontaneously.

 

It stands to reason that hubs supporting blades up to 18" x10", as the Aeronaut ones do for example, will be way over the top for a lightweight model.

[Erfolg]

That same brand is available from Robotbirds. I have one, it is fine.

[Tony Smith 7]

I see them I think.   The ones described as "Medium Plastic Spinner" etc.   You don't happen to know what shaft sizes they fit, and which blades are compatible?    Robotbirds don't specify what shaft sizes they fit, or what blades suit them, which is pretty useless.

 

They also do something called ""MULTIPLEX SPINNER FOR MERLIN 32mm with 3mm shaft" which might suit, except that I'd have to guess which blades fit it.

Or there's APC hubs of various sizes, but none of them specify motor shaft size ...

Do people just buy stuff at random and hope it fits?   

 

[Erfolg]

Tony

 

The spinner/hubs you want are on page 2 Link

[Tony Smith 7]

Got em ... down the bottom of the page,  "SPINNER-FOLDING NYLON 30MM-3MM SHAFTSPINNER-FOLDING NYLON 30MM-3MM SHAFT"   (also a 32mm and 40mm version for 3mm shafts as well).

 

You don't happen to know what blade they take?   I assume its one of Robotbird's ranges, but do you know if its their Graupner, Aeronaut or "Basic" blades?

 

Thanks .... you may be saving my project !

 

 

[Erfolg]

Tony

 

I only use Aeronauht or Graupner, at the smaller sizes they are normally 6mm. However some of the alloy bar types can be 8mm (but you are not buying alloy bar type).

 

Their (Robotbird) blades are a lot cheaper, but a wrecked model is quite upsetting

 

I normally start with  the data sheet type info. then back it up with amp meter. This approach is not always reliable, I then see if I have something similar, but say larger dia, or lower. The pitch I normally choose on the basis of the speed i am expecting. In reality 6" pitch for a faster model, 4" pitch if looking for a high climb rate at slow speed.

[Tony Smith 7]

Thanks again.  I've asked Robot Bird to confirm suitable blades.

 

Meantime the projects on hold - the flight pack exploded mid-air leading to a spiral dive from over 100', so I have some airframe work to sort out before I worry about propellers and brushless motors again!

[Tony Smith 7]

Still a definite lack of response from suppliers, which is a bit frustrating.   So I can find a couple of hubs which would suit, and the suppliers list all sorts of blades - but won't tell me which ones would fit those hubs.

 

How does it make business sense to offer stuff for sale if you can't or are prepared to say which bits fit together?  It seems lunacy to me, unless they really expect people to just order at random and hope it can all be lashed together in the end.

 

I've already been caught out by ordering blades for the old prop - described as 5mm root but in fact they turned out to be much bigger, and the geometry was such that they simply wouldn't have fitted even filed down to 5mm.

[Tony Smith 7]

The APC folding props also look suitable, but in that case the suppliers refuse to say what bits would be needed to get the hub to fit onto a 3mm shaft, or how to fit a spinner.  

[Simon Chaddock]

Tony

This lightweight & very cheap (£3.95 for two, including p&p!) 11x6 folder from e-bay has not given me any trouble and to cap it all it is just a push fit on the 3 mm shaft!

The motor is a 2822. Yes, it is only running only on a 2s pack but it probably still produces as much torque as your Tower Pro 2408 would on a 3s.

Edited By Simon Chaddock on 04/09/2010 22:00:12

[Tony Smith 7]

Cheers.  I that same seller (plus2city) does 6x4 and 7.5x4 props, which might be worth a try.