propellers

[simon w]

hello there im new to the forum and RC planes etc, i have a park flite Cessna 182 skylane and fitted a Quanum gyro flight stabilization thing on to it, lol now i tried fly it the other day and crashed it and broke my prop, {this was during take off lmao, i not actually flown it right yet}. the sizes on the prop say 8x6 and 203x152 so i put them sizes in to ebay and ordered a selection of different coloured props. they have all been delivered and it seems they are all different angles close to the bolting hole, i thought the 8 was the length of the prop tip to tip and the 6 was the angle, so my question is why do they all look at different angles but are all 8x6 ??? and another thing i read the ad for some props on ebay and didnt see the 10pcs for £2.65 i thought it was for 1 prop so ordered 5 , i now have 50 props that dont look right compared to the original lmao

[Nigel R]

Hi Simon

As you say the "6" is the angle.

Don't worry about the angle near the middle at the hub. Different brands often have different shapes. Sometimes the angle varies a little too.

The angle near the tip is more important.

The key point is, if you had 8x6, and your new ones are also 8x6, then all should be good.

If you have 50 props they should last quite a while!

[simon w]

thank you for your reply Nigel, ok cool, at least i haven't got worry about braking props for a long time now then lol.

[Andy48]

26p a propeller is awfully cheap. I would expect to pay at least £1-2 each for them. You might find the ones you have got are very flimsy, and not very safe.

[perttime]

Do all the props fit the prop shaft on your Cessna?

[Denis Watkins]

If you ordered different colours Simon, check them carefully

As Quadcopter sets come right and left handed, that is CW and CCW

Clockwise and Counterclockwise

The correct prop blows air to the tail

Tether the model down firmly to test

[simon w]

Posted by Andy48 on 30/06/2020 18:05:04:

26p a propeller is awfully cheap. I would expect to pay at least £1-2 each for them. You might find the ones you have got are very flimsy, and not very safe.

thanks for your reply, the new props feel just as flexible as the original.

[simon w]

Posted by perttime on 30/06/2020 18:05:39:

Do all the props fit the prop shaft on your Cessna?

thanks for your reply, now the ones i got that are different colours came with inserts for different size shafts but the big order i got by mistake ( 50 props ) look to be for a 6 mm shaft but came with no inserts, my plane motor shaft looks to be 4mm.

[simon w]

Posted by Denis Watkins on 30/06/2020 18:22:14:

If you ordered different colours Simon, check them carefully

As Quadcopter sets come right and left handed, that is CW and CCW

Clockwise and Counterclockwise

The correct prop blows air to the tail

Tether the model down firmly to test

thanks for your reply, yeah they all look to be the same rotation to the original ...

[Simon Chaddock]

simon w

Just out of curiosity I looked on ebay for those 10 times 8x6 and they should do fine. Do make sure the prop is a good close fit on the motor shaft using the correct bush included with them.

Remember a prop blade is twisted at a different angle along its length, shallow at the tip but near the root the shape is set by the loads generated when it is working.

The vast majority of the thrust is created by the outer 2/3 of the blade. The bit near the root contributes almost no thrust but it does stop the outer part flying off.

[simon w]

Posted by Simon Chaddock on 01/07/2020 19:15:11:

simon w

Just out of curiosity I looked on ebay for those 10 times 8x6 and they should do fine. Do make sure the prop is a good close fit on the motor shaft using the correct bush included with them.

Remember a prop blade is twisted at a different angle along its length, shallow at the tip but near the root the shape is set by the loads generated when it is working.

The vast majority of the thrust is created by the outer 2/3 of the blade. The bit near the root contributes almost no thrust but it does stop the outer part flying off.

thanks for the reply, ok cheers m8, depending on how good i get at flying it im pretty sure my props could out last my plane hahaha only time will tell !!

[Peter Monk 1]

Hi folks,

I'm pretty new to electrics and I've managed to confuse myself (confused of Canvey?). Thinking about buying a WOT Trainer so downloaded the build instructions from Ripmax. In the introduction they suggest what (WOT?) propellers to use. For i/c they rather unhelpfully say "Suitable Propeller" but for electric power they suggest an APC 12x9 wide.

Now I've had a good look and the only APC 12x9w I can find is stated to be for "i/c and nitro". Looking at APC's own page they dont seem to make a 12x9 wide for electric. Would it be ok to use this prop on the recommended Ripmax Quantum II 40 motor as I would wish to build for electric power?

[Martin Harris - Moderator]

I assume the recommended motor is wound for fairly slow rpm so there would be no problem using the APC if the recommendation is correct. "Electric" propellers are much lighter and the power impulses from an IC engine (shame that Ripmax are perpetuating the incorrect term "nitro" for a glow engine...nitromethane is an optional additive to the base fuel of methanol) would probably lead to failure - no such problem the other way round..

Put that 12 x 9 on an IC engine capable of spinning it efficiently and the model would likely float the length of Heathrow's runways at a reasonable tickover - hence the reference to using a propeller suited to the engine. A .40 2 stroke typical of a trainer would use something like a 10 x 6!

[Peter Monk 1]

Hi Martin,

Interestingly the English and German instructions are side by side and for the recommended electric prop they just use the word "luftschraube", literally airscrew with no mention of it needing to be thin or wide. So I think I'd go for the APC 12x9w.