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Old Sep 01, 2012, 02:02 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
3,480 Posts
No opportunity for progress over the last few days - I'm getting withdrawal symptoms! But whilst generally musing about the build (and taking delivery of a pack of 6x3 GWS props from HK), I wondered whether you chaps find it necessary to balance the props on these low powered motors? Now I know that prop balancing is always a good idea, but do you find it necessary?

Just an idle question....
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Old Sep 01, 2012, 02:45 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
4,427 Posts
Well, Colonel, for many years I managed quite well without prop balancing; however, I have to say that with bigger motors it does make for MUCH smoother running and two years ago I flexed the plastic and invested in a horrifyingly expensive but wonderfully efficient magnetic prop balancer. Having got this wondrous device I now balance all my props, an often tedious procedure, especially when trying to achieve a balanced hub. However, I have to say that the biggest improvements are undoubtedly on the more hefty props and motors, and I can't say that on such as GWS 5 x 3 and 6 x 3, running on the little 1811 motors, there is any dramatic difference between a prop straight out of the packet and one I have balanced. On the other hand the improvement in smooth running and quietness on motors in the 120-250 watt range such as I use in the Tom Tit, Mamba and Mars with 8 inch props is very evident.

The only point I would make is that, if you ARE going to balance the smaller prop sizes in particular, you really will need something as sophisticated and friction free as the magnetic set-up. But for the set-up you have in the Ajax, I wouldn't worry, the little GWS props are quite good as bought.

BTW, glad to hear you are getting withdrawal symptoms - otherwise known as "builder's twitch". Told you it was fun!
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Old Sep 01, 2012, 06:45 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
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Thought you might like to see my hideously expensive Topflite magnetic prop balancer. It IS nice though and packs away neatly for storage!

But you really don't need it for the small size GWS props. What you DO need, if not using the "prop saver" mounting (i.e. mounting the prop on a collet prop adapter) is some means of opening out the prop centre hole to fit on the prop driver threads whilst ensuring that the hole remains properly concentric. The best way of doing this is with a prop reamer, stepped for preference but tapered if not. A badly drilled or over-size hole will inevitably cause vibration.

See
prop balancing video tutorial (5 min 5 sec)
for a decent short tutorial on prop balancing. Generally speaking getting the blades to balance is the easy bit, getting the HUB to balance is much more fiddly.
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Old Sep 01, 2012, 07:16 AM
Sic itur ad Astra
sparks59's Avatar
United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
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I use this one, it doesnt fold away like SD's but works a treat.
I dont always bother with the small GWS 5x3 's as they tend to be near perfect out of the bag. But others tend to need a little bit of balancing. The motors run so much smoother with the prop in balance.

http://www.hobbyking.com/hobbyking/s..._balancer.html

sparks
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Old Sep 01, 2012, 07:39 AM
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Gluehand's Avatar
The windy west coast of Sweden
Joined Sep 2008
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On prop balancing, and more.....

Quote:
Originally Posted by Sundancer View Post
Thought you might like to see my hideously expensive Topflite magnetic prop balancer.
Watch this interesting FILM CLIP ...

* The first part shows some Swedish aviation of 1915.

* The second part shows the THULIN aircraft factory 1918.
At about 4:56 you can watch the hi-tech (LOL) method of wing spar testing....
At about 5:44 you can see how well balanced the props were....

All in all, some interesting & unique documentation of yesterday's aircraft making, not least the manufacture of the Thulin radial engines...

Enjoy...!
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Old Sep 01, 2012, 08:43 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
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Quote:
Originally Posted by sparks59 View Post
I use this one, it doesnt fold away like SD's but works a treat.
I dont always bother with the small GWS 5x3 's as they tend to be near perfect out of the bag. But others tend to need a little bit of balancing. The motors run so much smoother with the prop in balance.

http://www.hobbyking.com/hobbyking/s..._balancer.html

sparks
That looks very nice Sparks, if I had been aware of it at the time I would probably have bought it rather than the TF one, given it is less than half the price!

Forgot to say; checking the prop tips for correct tracking, especially after opening out the holes, as described in the tutorial, is a crucial step.
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Old Sep 01, 2012, 03:08 PM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
3,480 Posts
Thanks all - pretty much as I thought re the balancing. Thanks for the videos as well, chaps!

I managed to get into the loft a couple of times today - there is advantages when young Pippa Blinkette has a friend over - they were out on the east lawn having an amusing game of croquet which kept them occupied whilst one stole up the east staircase....

Control surfaces have been hinged with Blenderm, and I've managed to complete the covering of the fuz; this doesn't seem to be patchy like the white tail feathers. But the coloured tissue is without doubt different to the white; the blue definitely has a more open consistency with wider spaced fibres. This will allow the varnish to pass through it more easily, and I think this is the basis of the issue with the white.

Having covered the fuz, I started to cut black tissue for the cockpit glazing. However, I'm really having second thoughts about this on a dark blue fuz. It's not prominent enough and as the fuz is quite deep anyway, simply makes it look even deeper. Hence I'm erring toward 'proper' glazing after all. Question - what's the best method? Is it simply a case of gluing the celluloid on the outside of the framework, or is there some secret method of insetting it into or behind the frame???
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Old Sep 01, 2012, 05:22 PM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
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That is looking really nice Colonel. Re glazing, most of us do just stick it to the outside, never terribly satisfactory especially as a lot of contemporary glazing material displays a great reluctance to be stuck by anything, and CA adhesive tends to mist it and make t look awful. If you opened up the cabin roof where the wing fits (normally left uncovered anyway) you COULD glaze it from the inside, but the problem of sticking the stuff would still remain. It strikes me that, as the glazing on the Ajax is all flat panels, it would be an ideal subject to use document laminating film on. If you could scrounge an A4 laminating envelope (from your place of employment?), this would provide ample material to glaze the cabin and windshield and could be cut to shape neatly, then ironed on round the edges and shrunk tight, would be very neat.
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Old Sep 01, 2012, 05:54 PM
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Stockport, UK
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Good quality (3M or scotch ) double sided tape cut into strips holds thin plastic for glazing quite nicely. If you use acetate thinned dope can be used to dope tissue frames to cover the tape. Sounds a bit of a fiddle but is quite easy to do and no risk of getting glue all over your glazing.

Cheers
Ian
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Old Sep 01, 2012, 07:24 PM
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Australia, WA, Perth
Joined Nov 2010
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Lovely job colonel, blue is a cool fuz colour. For the record, I use canopy glue from the LHS and it seems to work on all the clear plastics I've tried. You could have used the mylar covering underneath as windows as well but it is quite fiddly. Gary
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Old Sep 02, 2012, 01:09 AM
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Gold Coast Australia.
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Contact cement does a good job also for the glazing.
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Old Sep 02, 2012, 03:34 AM
Sic itur ad Astra
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United Arab Emirates, Abu Dhabi, Abu Dhabi
Joined Aug 2009
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I use a locally available general purpose glue, it's a bit like balsa cement in scent and consistency. I needs to be pinned in position but is clear and seems to hold acetate in position reasonably well.

Always a fiddly job though, on the Coupe I used two very small self tap screws, one at each side, seems to have worked alright.
sparks
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Old Sep 02, 2012, 03:54 AM
RFJ
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Northern Ireland
Joined Dec 2004
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I have always used balsa cement in the past with good results but on my last model I tried UHU Por, the stuff the foamy people use on their models.

It worked very well although a bit stringy to apply. It can be applied to both surfaces, left to dry and used as a contact glue or just applied to one surface giving a bit of sliding about time. I used the latter technique. Either way it gives a very strong bond.

Ray
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Old Sep 02, 2012, 03:58 AM
*jj
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United Kingdom, Birmingham
Joined Jul 2008
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Like kkphantom, I use 'canopy glue' which works well. (On models with curved screens, I stick one side first and leave it to dry, before doing the other side).

I also stick the windows on first, and then put the covering on top of the overlap of the frame, which IMO looks neater. Bit late for you, though ...
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Old Sep 02, 2012, 03:07 PM
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Quote:
Originally Posted by Ian Dale View Post
Good quality (3M or scotch ) double sided tape cut into strips holds thin plastic for glazing quite nicely. If you use acetate thinned dope can be used to dope tissue frames to cover the tape. Sounds a bit of a fiddle but is quite easy to do and no risk of getting glue all over your glazing.

Cheers
Ian
I stick to Ian's sentence!
It's a good way to hold thin plastic, specially if the wood frame is properly doped and sanded.
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