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« on: June 29, 2015, 10:38:47 PM »
K K Iyer
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Of the 10000+ members, i think 1 or 2 are experimenting with rubber powered models.
This is for them.

1. Cut appropriate size blanks from 1 to 3 mm balsa.
2. Draw outline of prop.
3. Soak blanks in hot water for a minute or two
4. Tape on to a can/bottle at about 30degrees.
5. See pics and decide which way to slant the blades - left or right? Which will give more pitch at root and less at tips?
6. Allow to dry overnight.

@saikat sir,
Perhaps you would like to tell people what to do after the blades dry...


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Home made prop for rubber power
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« Reply #1 on: June 30, 2015, 10:27:17 AM »
wingmanbunty
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“Of the 10000+ members, i think 1 or 2 are experimenting with rubber powered models.
This is for them.”
This is not true sir we still build and fly such models along with rc.even i build my own
 mango wood prop for planes, my work is at experimental stage
I apologize, my intention was not to hijack your blog. Sorry for that please carry on.... Hats Off

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« Reply #2 on: June 30, 2015, 10:54:18 AM »
saikat
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Well done Bunty - very nicely carved props.
If I may suggest - omit the scimitar shape - as it adds nothing and unnecessarily makes carving more difficult.

Any way to follow up on KK's first post

once you have dried the blades overnight - you will have a pair of blanks with a helical twist permanently molded in.

then cut the blanks to your desired planform - ie - the shape of the prop blades - you can use whatever shape
pleases you - its not critical - just make sure both are identical.
then you have to stick the blades to a hub. This can be a length of square strip wood with the ends sanded to
45 degree (again not critical) flats so you can glue both the blades. Drill a hole at right angles so that the prop shaft
can be fitted. (be careful while making the hole - take your time to make sure that it is perfectly perpendicular - otherwise
you will have a wobbly prop)
lastly give a coat of paint and balance. Attaching some pics
one is of a prop whose blades were cut from a plastic two ltr soft drink bottle - the advantage here is that you
get the helical twist pre formed. Last is of an old time rubber whic I am building as a 3ch Rc

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« Reply #3 on: June 30, 2015, 12:43:44 PM »
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@wingmanbunty,
@ Saikat sir,
Thanks for the contributions.
Its not a hijack at all.
The very purpose of the thread was to elicit contributions from knowledgeable members on subjects that many may be unaware of.
Keep it coming! Like free wheelers, folders and single bladers.
(Bunty, are your hand carved props for glow or electric or rubber? Or do you make for all three?)
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« Reply #4 on: June 30, 2015, 03:10:12 PM »
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Sir why I think I ruin your blog, okay last statement about the wooden prop   my work is
at experimental stage as I got success I will share it to everyone, what I come through this  is we need to have correct pitch along with washout  on both sides .At small size prop, even the minor grinding ruin the work that creates vibration which is not good .
Prop copier machine is answer to this problem but it is used in large size prop ex. Para motor, we have to scale it to small size that I am working on. 

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« Reply #5 on: June 30, 2015, 06:24:27 PM »
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@Wingmanbunty  Salute Salute
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« Reply #6 on: June 30, 2015, 08:33:58 PM »
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@wingmanbunty,
I never knew of something called a prop copier!
Learnt something new.
So far i never tried to carve a prop, thinking its impossible.
Now i am encouraged to try, after seeing your work.
Though i doubt i can match the accuracy and finish of the Top Flite wood props.

Please continue.
Regards.
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« Reply #7 on: July 17, 2015, 12:36:51 PM »
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Iyersir

I tried very similar method you mentioned here. I let the blanks of 1/32, 1/16, 3/32 sheet wet in water overnight at room temperature then rolled those pieces on some plumbing PVC tube of 3" diameter and let it to dry.

[ATTACH]6689873[/ATTACH]This one is of balsa. Two things I want to say about it. 1. I made mistake that this is clock wise rotating prop. 2. This is not crafted purely as above method from a block, but its from 1/16 in sheet balsa.[/QUOTE]]
Quote from: drpiyush;28112298
[ATTACH]6689873[/ATTACH]This one is of balsa. Two things I want to say about it. 1. I made mistake that this is clock wise rotating prop. 2. This is not crafted purely as above method from a block, but its from 1/16 in sheet balsa.
[/url]

but left due to not happy with flight performance. The issue is off course with the rubber-band. i never get the unwinding smoother or slower. Is stretching necessary before using  a new rubber? I used rubber that is double of the length of fuselage.
« Last Edit: July 17, 2015, 12:57:27 PM by PiyushI » Logged

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« Reply #8 on: July 17, 2015, 02:31:08 PM »
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See this thread.  http://www.rcindia.org/kites-trains-free-flight-and-all-others/query-regarding-rubber-band-powered-plane/25/
My wooden props are so good - see the vid on next page. The rubber length needs to be just ahead of the fuselage length for usual rubber bands.
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« Reply #9 on: July 17, 2015, 04:44:11 PM »
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Is stretching necessary before using  a new rubber? I used rubber that is double of the length of fuselage.

Try this. Take a loop a little over twice the required length. Get someone to hold one end in a  (1st) hook. Stretch the other end and put some turns on it. Now hold the centre of the length in a (2nd) hook. Bring the two ends together and put them on the first hook. (The 1st hook can be the anchor, the 2nd could be the prop hook). Release (ie, allow to rotate). The two halves will braid themselves together, and be about the required length. This is a pre-tensioned braided motor!
Regards.
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« Reply #10 on: July 17, 2015, 07:06:26 PM »
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Wow! That's the perfect advice I too needed! Thanks sir; I am also gonna try this!
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« Reply #11 on: July 20, 2015, 07:53:56 AM »
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Is stretching necessary before using  a new rubber? I used rubber that is double of the length of fuselage.

Try this. Take a loop a little over twice the required length. Get someone to hold one end in a  (1st) hook. Stretch the other end and put some turns on it. Now hold the centre of the length in a (2nd) hook. Bring the two ends together and put them on the first hook. (The 1st hook can be the anchor, the 2nd could be the prop hook). Release (ie, allow to rotate). The two halves will braid themselves together, and be about the required length. This is a pre-tensioned braided motor!
Regards.
Great sir. This is what why a good guru is always required. Hopefully, today I'll try this.
Thanks for the tips.
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