Conference vmszoo::rc

Bob,

There are several other prop manufacturers worth considering.

	Tipan is an Australian designed and manufactured prop that is
available overseas. It is a good design and good accuracy.

	Carl Golberg (sp) make a more expensive prop but it is a glass prop and
hence is stronger than the others.

	Prather used to make props but I have only ever seen performance props.
They were good quality.

As for the others you mention. Master Airscrew are generally accurate although I
have seen some badly pitched props recently. with the MAS props a few words of
warning:

	1. Remove any flashing on the leading or trailing edge. It will carve
	   nice pieces of skin from your finger.

	2. Never run a 10/6 at more than say 15,000 RPM, they tend to throw 
	   blades. The bigger the prop the lower the sake speed.

	3. If you heavy land and hit the prop check it very carefully for any 
	   crack and discard if in doubt.

Zinger do make a plastic prop I believe, I have never used it but Zinger are a
reliable company so it should be ok.

On the wood props it is a bit of a lottery. Some batches are good some are
terrible. Always select the prop by appearance looking for:

	1. Consistent, straight grain along the length of the prop without any
	   imperfections or dramatic change of color.

	2. Good finish to the hub of the prop.

You will probably get sour looks from the shop attendant doing this but I like
to let somebody else get the bad props and break a blade.

Of the wood props Rev-Up are probably the better if you don't want to work them,
Top Flight are also ok, Zinger are so-so but have the advantage there is plenty
of wood to correct the pitch and improve the profile if you have the equipment
and the inclination.

Three bladed props as you say do reduce noise from the reduced tip speed, the
other advantage is the reduced disk size if you have a ground clearance
problem. There is one big disadvantage in that is reduces the amount of
undisturbed air moved by the engine as the frontal area of the model erodes a
larger percentage of the prop disk.

While on props, always balance a prop removing material from the front not the
the side closest to the engine, a High Point balancer is the best but the
finger type are adequate. If you are going into changing the pitch use a pitch
gauge like the Prather but get some advice from somebody who knows what they
are doing as it can be dangerous.

John

        Re:< Note 864.1 by GIDDAY::CHADD "Go Fast; Turn Left" >

                Don't forget the RR of props: Graupner.
        

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         Hang in there! o_|_
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             Anker      \_|_/

< Note 864.2 by CURIE::ANKER "Anker Berg-Sonne" >
                                 -< Graupner >-

>                Don't forget the RR of props: Graupner.
        
Too true, Anker. Great props, very accurate and consistent.

John

    I love Graupner's, too. I know most of you use Master Airscrew
    props, but I don't like them at all. I've never had one fail
    on me, but they have very sharp edges (I use a chicken stick
    with them even after I've sanded the flashing off the edges)
    and they are very noisy - both attributes I think are due to
    the thinness of the blades.

    Wood props are the quietest.

    Anybody know a reliable source of Graupner props?

    Dave

re: < Note 864.4 by LEDS::HUGHES "Dave Hughes (LEDS::HUGHES) NKS1-1/E3 291-7214" >
                              -< graupner for me >-

>    Wood props are the quietest.

Wood props when carefully selected are also much safer than the MAS. Believe it
or not they are much stronger. 

A thought that came to me is a word of warning about sealing a wood prop if
(correction: WHEN) you balance it. Fuel has a habit of making them go flexible
and then they vibrate badly. A good quick sealer is CA applied thinly to the
exposed area.

>    Anybody know a reliable source of Graupner props?

They seem to be readily available in Oz but some of the popular sizes can be
in short supply at times.

We have a local prop manufacturer called "Bolly" who makes glass/carbon props.
I was told last night that he is exporting them. If you see them give one a go,
they are mainly performance props and four stroke, excellent quality.

John
    

    Graupner props are great but the price seems to have gone through
    the roof lately.  The last ones I bought were about $2.10 for a
    10/6 and they now are almost double that.  Hobby Lobby seems to
    be the only mail order supplier but some of the hobby shops including
    Ray's in Worchester have them.  The popular sizes seem to go first.
    I used the same one all last year on my SS40.  They are almost
    indestructable if you don't hit rocks with them.  They seem to be
    very well made and are balanced right out of the box.  The hole
    size seems to be too large for many of the OS engines though.  I
    have had to make a plastic bushing out of tape to center the prop
    on the shaft.
    
    Charlie
    

    I get my graupner's from Hobby Lobby. Because of the inavailability
    at most hobby shops, I buy them in bulk. Only trouble is, like Bill
    and Charlie said, the most popular sizes like 10/6 props go quick
    at a shop that carries them. 
    
    Tom

Re: < Note 864.7 by LEDS::WATT >

>    They seem to be
>    very well made and are balanced right out of the box.  The hole
>    size seems to be too large for many of the OS engines though.  I
>    have had to make a plastic bushing out of tape to center the prop
>    on the shaft.
    
Try using brass/aluminium tube to adjust the hole size even if you have to ream
the prop hole a little larger.

PVA tape would not be an accurate way of filling the hole and it would destroy
the benefit of a well balanced prop.

John.

    
    I used a small piece of shim material cut to wrap around the prop
    shaft exactly once (without overlapping itself).  I chose the width
    to make a fairly snug fit and it didn't seem to affect the prop
    balance.  John's idea is a good one though.
    
    Bill

    The shim required for Graupner props is very slight.
    I've seen people just center them by hand and tighten
    them up with no apparent problems.

    I use a piece of a soda straw. I slit the straw so
    it fits on the shaft, and it's just enough of a shim to
    make the prop fit tight.

    As far as finding Graupner props, Ray's method is to put
    in an order and then wait until they're all gone and order
    some more. He was also complaining about the fact that
    they won't take his credit - he has to include payment
    with his order to get the props. Imagine that.
    

    Eric,
    	If you noticed, I usually use rubber props for that reason.
    I have the same Graupner 10/6 prop on my SS40 that I put on it for
    its first test flight 2 years ago.  Now that I said that, I'll probably
    break it next time out.  If I do, the plane will probably be in
    a body bag since that's the kind of crash it takes to break one
    if you soak it in water a couple of times a year to keep the moisture
    up.  I don't plan to try 3 bladers on my Sportsters.
    
    Charlie
    

Another plug for graupners... I've been using them for years - in some
cases, the same prop for a few years of regular flying(and crashes)

I have yet to find anything better!

/Brian