P-51 3 or 4 Blade prop?
 

I'm building a Top Flight 63'' w.s. P-51. Does anyone know if there is a 3 or 4 blade prop that it will FLY with? Am using a Saito 100. Thanks for any input!

RE: P-51 3 or 4 Blade prop?
 

I don't know if there ARE any, but I can tell you that you don't want to fly with one. Compared to a Full Scale plane, the distance between the blades on a model's prop is so small, that with a 4 bladed prop, each blade will get lost in the wash of the blade before it. At higher RPM, the 4-bladed props become very inefficient.

RE: P-51 3 or 4 Blade prop?
 

There are 3 and 4 blade props made... and you can (if you know how...) cut 2 wood props and bond up the hub with a ply disk on each side to make your own.

With the Saito 100... if the weight of the airplane is reasonable there will be ample power to not worry about the inefficiency issue. You will not a significantly longer take-off roll is needed than with the 2 blade prop. top speed might increase, as the inefficiency goes away as airspeed increases. (otherwise the ducted fans with 5 to 9 blade rotors would never work)

RE: P-51 3 or 4 Blade prop?
 

APC and Bolly make 4 blade props, but I don't know if they have one that will work on the Saito 100.

RE: P-51 3 or 4 Blade prop?
 

My local LHS owner has told me that most 4 bladed props on a P51 are for static display. I do not know whether this is correct or not, but he has sure been doing this longer that I have.

RE: P-51 3 or 4 Blade prop?
 

The LHS owner is correct.

The increase of static thrust with the longer 2-blade prop is significant for many models. It allows a steeper take-off climb with less chance of stalling. Stalling on take-off is one of the easiest ways to rekit a P-51. (they don't behave well in a stall durring take-off...)

That's why I said "if the weight is reasonable"..... A P-51 of that size can esilly fly on the power of a .61 2-stroke (.72 to.80 4-stroke) if its isn't overweight. With the Saito 100... he's going to have almost the same prop diameter 4-bladed as the .71 would with a 2-blade.

RE: P-51 3 or 4 Blade prop?
 

And it will look better on the ground.
Something wrong with a two bladed P-51.

I have the Zinger 4-Blade system purchased for my TF Giant ... hope all goes well this summer.
Each blade is removable on a machined hub ... if this doesn't work, I will try the thin bladed 15.5 X 12 available from Bolly ( I believe)

Moki 2.10 power !

RE: P-51 3 or 4 Blade prop?
 

I do not know what is the proper 4 blade prop for you engine but I recently bought one from [link=http://www.zingerpropeller.com]Zinger Propellers[/link] and installed it in my Pilatus Turbo Porter which has an OS 120. It looks very scale but I have to admit I get less power than with a 2 blade prop. I am going to experiment with different combinations to see what gives me the best performance.

The good thing about Zinger props is that the blades are mounted between two plates and each blade is individually attached with screws. This means that you can change individual blades without replace the whole prop. The cost of each blade hovers in $2-$3 which means changing diameter or pitch will cost you some where $8 and $12. He also makes very scale looking P-51 spinners.

RE: P-51 3 or 4 Blade prop?
 

It will look better on the ground if the prop is almost scale in diameter. For a TF .60 size Mustang, this means a diameter of close to 19 inches. Anything less than 16" will look like crap. There is something wrong with a dinky 4-bladed on a P-51.

My buddy used to have a 3-bladed prop on his Corsair, and it didn't have very good top end speed. He replaced the 3-bladed prop with a 2-bladed prop, and performance increased significantly, including top end speed.

RE: P-51 3 or 4 Blade prop?
 

Where can you find a spinner for a 4-bladed prop for an H9 .60 P51? Or do I have to carve two extra slots on an existing one? I want to use it for static display.

RE: P-51 3 or 4 Blade prop?
 

Tru-turn makes 3 and 4 blade P-51 spinners.

RE: P-51 3 or 4 Blade prop?
 

--> [link=http://www.truturn.com/cgi-bin/store/agora.cgi?keywords=P-51&ppinc=1aspinners&maxp=30]Tru-Turn[/link]

RE: P-51 3 or 4 Blade prop?
 

I'm building the TF Spitfire. After looking around, reading posts and reading articles, I've decided to go with the RCV 90. It's a 4 stroke with a 2:1 gear ratio. The 90 will throw a 15.5x12, 4 blade prop. This should look respectable and give pretty good performance. The inline cylinder design will fit nicely inside the long cowl of the Spit as well. Now if I can figure a way of getting cool air in without a large hole in the cowl, and add functional scale exaust pipes too . . .

I hear these engines are best started with a special adapter because the crank shaft is vertical and the gearing puts extra stress if hand or chicken stick started. They say it can be done, but untill I feel more at ease with the idea, I'll use the adapter. This will require a small hole in the top of the cowl. I hear it takes between 1 and 2 gallons of fuel to break them in and they have a whine due to the gearing. In all, I think having a good sized 4 blade and not having a cylinder sticking out the side or bottom of the cowl will be a real eye catcher.
They also have 60 and 120 size engines in this design as well.