I just bought an eflight bnf p51, I love it, but I wanted to get some spare props for it because I knew I would need them. My local store was out, on backorder until August. So I figured, I'll just buy one online.

Got the p51 home, flew it for about an hour and damn if I didn't break the prop. Problem is, apparently there is some global shortage because nobody has these 4 blade 10.5x8 props anywhere and the earliest I can get them is Aug...

Anyone know what gives? Also, any recommendations on alternative sources or even alternative props that might work well for this?

Thanks a ton!

Originally Posted by Habeas81

I just bought an eflight bnf p51, I love it, but I wanted to get some spare props for it because I knew I would need them. My local store was out, on backorder until August. So I figured, I'll just buy one online.

Got the p51 home, flew it for about an hour and damn if I didn't break the prop. Problem is, apparently there is some global shortage because nobody has these 4 blade 10.5x8 props anywhere and the earliest I can get them is Aug...

Anyone know what gives? Also, any recommendations on alternative sources or even alternative props that might work well for this?

Thanks a ton!

There's not really a lot of demand for them, they're all made in China and the entire international shipping industry is having a few minor issues.

You're right about some sizes of props seemingly disappearing, for me I'm missing 7x4.5" 3 blade clockwise/counterclockwise props, used to be an abundance and now basically nothing.

The 250 size racing quads have really taken off in the past few years, that created a huge demand for smaller props than are traditionally used on larger quads and fixed wing, I get the impression propeller production in China has shifted to meet that demand. There are endless listings for multirotor props in sizes I don't use everywhere I look.

APC have a 10x6" 4 blade that would be a decent replacement, diameter is by far the more important number to match and be concerned about, pitch isn't so much. Matching props to motors is a pretty complex subject and one that's easy to mess up, it's pretty mandatory for me to suggest an ecalc subscription to do the math for you.

A rule of thumb to go from a 2 blade prop to a 3 blade is to drop an inch of diameter and keep the same pitch, eg if you had a 12x6 2 blade that could be replaced by an 11x6 3 blade. This works - again as a rule of thumb - going the other way as well, 10x8 4 blade could be replaced by 11x8 3 blade or 12x8 2 blade. You may be better off with less pitch actually, 8" is quite steep on a 10" diameter.

A wattmeter is also an essential purchase when you start changing out props, it's a lot cheaper than a burnt motor or speed controller.

Originally Posted by Habeas81

I just bought an eflight bnf p51, I love it, but I wanted to get some spare props for it because I knew I would need them. My local store was out, on backorder until August. So I figured, I'll just buy one online.

Got the p51 home, flew it for about an hour and damn if I didn't break the prop. Problem is, apparently there is some global shortage because nobody has these 4 blade 10.5x8 props anywhere and the earliest I can get them is Aug...

Anyone know what gives? Also, any recommendations on alternative sources or even alternative props that might work well for this?

Thanks a ton!

Take your pick........
https://www.rc-castle.com/index.php?...roduct_id=6258

https://www.rc-castle.com/index.php?...roduct_id=3319

https://www.rc-castle.com/index.php?...roduct_id=4900

https://www.rc-castle.com/index.php?...roduct_id=2995

https://www.rc-castle.com/index.php?...roduct_id=2864

https://www.rc-castle.com/index.php?...roduct_id=2475

https://www.rc-castle.com/index.php?...roduct_id=8654
These are all the same props (except I believe the first one, as it’s composite) other than the painted tips.
It’s pretty well known that some of the Horizon Hobby planes are made by FMS. So they all use the same prop.
So if your local hobby shop carries FMS you might have a chance.
Also the Dynam B-26 uses the same size prop. One standard rotation and one reverse rotation, so if you go that way, make sure you get the right one.

LURCH

Thanks for the links. The surface mail shipping is 45-65 days :0 I definitely appreciate the note about FMS, I am new and didn't really know that, it's definitely helpful info.

Is it possible to change the prop out for something that is more component based? I mean this to say a central hub to hold individual blades that can be swapped out of the hub if they break? If so, what are the parts I should look for to convert to this style of prop?

Thanks!

That's how the props on many FMS models are assembled, individual blades that screw in to a hub. But the hub is easily broken, it's just plastic. I had thought about machining one from some Aluminum. IMO replaceable blades is better as a concept than in practice...

You don't need 4 blades, or even 3. You can fly it with a 2 blade prop. I'd try an 11x8. This will give you the same pitch speed, and the slightly bigger diameter will compensate some for the loss of 2 blades. Power goes up to the 4th order with diameter, so you don't want to increase diameter too much.

Originally Posted by Habeas81

Thanks for the links. The surface mail shipping is 45-65 days :0 I definitely appreciate the note about FMS, I am new and didn't really know that, it's definitely helpful info.

Is it possible to change the prop out for something that is more component based? I mean this to say a central hub to hold individual blades that can be swapped out of the hub if they break? If so, what are the parts I should look for to convert to this style of prop?

Thanks!

I was told the same on shipping, but received an order from him in 10days only a week ago.

How did your original prop brake? Does it happen to have two opposing blades left by any chance.
If it does you can actually fly it like that.
The video below is of a Durafly A-1 Skyraider that uses the same blade.
I’ve done it with my Durafly Corsair and found it no different to fly. Maybe a tiny bit slower but hardly noticeable.

Durafly Skyraider (4 min 12 sec)

LURCH

Multi blade props are not "necessary" but are mostly for scale looks with power off. When spinning, it's hard to tell number of blades and two-bladed props are more practical and cheaper to replace. Save your 3 and 4 blade props for display.