DragonHeart

Hi Guys,

Just a quick question is thier any particular manufacturer of props better than the others are they all about the same quaility ? The makes we have over here in the uk tend to be APC, Master Airscrew and Graupner i normally go for APC but ive brought some Graupner props and they seem alot stronger ????????? Is it me or are they better ?

Thx for any info

FHHuber

There's all kinds of trade-offs in making a propeller just as in designing and building an airplane.

The APC's are very stiff and efficient, but are fragile if you nick the ground. You chip an APC... its over, trash it.

Master Airscrew balck nylon props are more flexible and less efficient... but they can survive a few nicks. (I had one survive getting 1 inch dia ground off over 3 months of flying...)

Better is relative... better for what?

Pjtg0707

Personally, I prefer wood, MA and other/APC in that order in the US. I have not tried Graupner props, as they are rather scarce here.

APC props are WAY overrated for what they are. They are supposedly efficient, but who ever checked that?
They are also extremely heavy props. The difference in weight between APC and a wood or even a MA prop might not be so noticeable, but they become quite heavy at larger sizes.

If you dig out your college physics textbook and look up rotational inertia and rotational energy, you will find
rotational energy accounts for most of the total kinetic energy, and rotational inertia is linear in mass and square in radius of the prop. All this means is that you have all but a small fraction of the total amount of energy available from the engine that actually contributes to making the plane move.

MinnFlyer

My Feedback: (4)

I'm not too particular, except in one area... I REALLY like Graupner props for 4-strokes. They are a NOTICEABLE improvement over anything else that I have tried (And I have tried many)

Jim Schwagle

My Feedback: (1)

What? Although I'm no aeronautical engineer, the "best" prop would seem to depend upon many things other than the rotational kinetic energy or moment of inertia of the prop. Propeller efficiency is very complicated and according to people I am acquainted with, who know far more than me, it's subject to much experimentation. Once the prop is up to speed, the kinetic energy of the prop remains constant (apart from changes due to RPM changes), none of the engine's energy is "lost" in the prop due to its moment of inertia. At least that's the way I see it. APC's are quieter, which means less energy is lost to sound and their pitch is relatively true. I like Graupners, but the two I have are big wide bladed props, meaning they wont turn high rpm's, but will pull well at lower rpm's, hence my use of them in a big bipe. My preference for 40 - 120 sport planes, APC.


Edit for grammar, Duh!

Jim Thomerson

I usually try an APC first, but I think it worthwhile to try several different makes of prop to see which one suits me best in a particular application.

Jim

RCaillouet3

I generally use APC. I find the ones that I use to generally be lighter than Master Airscrew. I will agree with what has been said about Master Airscrew being possibly better on 4 strokes. I just seem to use APC for most of my flying. The slight amount of difference it makes may be important to serious competition flying, but just for sport and fun flying, fly what you got until you find one you like!

Reg

PS No real experience with the Graupner, sorry.

Montague

You should always try a few different sizes and brands of prop, it's not uncommon for one brand to perform more to your likeing on one engine/airframe combination, while a different prop or brand works better with another combination.

I use MAS props in RC competition partly because they are more durable, and that matters for me in that case. In the 7x4 size, the MAS prop also pulls the plane better than the APC 7x4, which I didn't expect. But I get noticeably more climb and a faster level speed.

On the other hand, on my OS .61FS, the MAS props were horrible, very little thrust. When I went to an APC, the vertical up lines improved dramatically, takeoff roll was shorter, etc. It was like going to a larger engine with out the extra weight. I also tried several different sizes and types on that plane, a couple of brands of wood, the APC and MAS, etc. Finally settled on a 13x6 APC as the best pulling prop over all, but the 14x6 Top Flight wood prop resulted in a better forward tumble, probibly due to lighter weight (CG moved rearwards) and engine torque effects.

I've never tried a Grapner.