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Old Sep 08, 2008, 01:33 PM
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Ljubljana Brnik, Slovenia
Joined Sep 2004
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Quote:
Originally Posted by willfly
Here is what I have been building. Carbon joiner rods are also glued to I beam between formers F1 and F2. Joined wing will be held down with 4 screws and has dihedral as per plan.

Hope it holds up in rowdy thermals. First flights will witness aggressive maneuvers and somersaults to verify integrity.
Very noble, to share your approach to make wing joiner with us!

I would use some ply to make joint and root ribs more durable....as ply is harder than just balsa.

Mitja
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Old Sep 08, 2008, 01:44 PM
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Ljubljana Brnik, Slovenia
Joined Sep 2004
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Quote:
Originally Posted by buzziehv
Hi Mitja,

now I am working on the 4th part of the wing (right-outer wing panel).

I have a comment regarding the Guppy_templates.pdf .

When I was working with the wingtip of the left-outer wing I was realized, that I had to sand a lot from the top-spar in order to be in plane the top of the wingtip.
At the right wingtip I was confused, because I saw in your assembly manual a very nice wingtip formed like a rib. But as I carved the places of the bottom sheeting and spar I was slightly more than the half of the thick of the wingtip.

Then I calculated a bit.

Your template writes that the wingtip is made from 6mm balsa.
And the layers from bottom to top:
  • 1mm sheeting
  • 2mm spar
  • at least 1mm of wingtip center
  • 2mm spar
  • 1mm sheeting
So only the sum of sheetings and spars is 6mm, so the wingtip has 0 for the thick.

In the right wing panel I solved it, that I glued it to the bottom sheeting and spar, then I cut through the wingtip and glued the top spar. I think that glue is harder then balsa, and it will be strenghtened with a balsa-triangle.

And I am thinking of another thing.
The optimal size of the propeller.

I will use a 46g 1050kV 4-12A (shortly 15A) outrunner brushless motor.
If I calculate AUW of ~500g and I am planning to build the hotliner wing also I am hesitating amongst some sizes.

I have some uncertified measurements from the internet regarding this motor:

Prop..........Thrust(g)..Amps
10X4.7APC. 900.........18.38
10x3.5GP....880.........17.95
9x4.5GP..... 800.........15.94
9x3.8APC... 760.........13.51
8x6GP........620.........10.51
8x3.8APC....620.........14.1
7x4APC.......440.........7.18

So what I am really thinking, that 7x4 has the best thrust/Amps ratio, but if I want to use it as a hotliner also it could be weak.

What I do not know, whether I gain more climbing (reduced climbing time) if I choose higher pitch propeller or not.

I am tending to choose a 8x4.5 or 8x6 Graupner CAM folding prop.

9x5 is also temptating, but will it not be too large for the Guppy? What speed likes it?

Thanks,

Tom
Uff Tom... I was "out of office" for a while.... I must read that carefully and write an answer later... sorry..

Mitja
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Old Sep 08, 2008, 03:18 PM
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Joined Dec 2007
55 Posts
Hi Mitja!

Welcome on board again!
I am the happiest to know that You are here!

You asked me in the beginning when I find any "mistake" I could sign it.

So I have found one. In your plan in the side-view the wing attachment at TE is not lower ~2mm, than the surface where the TE touches the side of the fuselage. The front wing attachment is "ok".

It is very interesting to me to build your plane as a first own build one. I chose this because the author (You) are here and can help me through the internet. It is a big big help for me. And I love to do this activity.
(and my family accept this hobby also! )

So now I am speculating how to sign and drill the holes in the wing as I follow your assembly manual.
I think I will make a template from 1mm balsa for the positions of the holes and I will glue it to the bottom of the wing as I set up the wing to right position and drill the holes what this template shows.
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Old Sep 08, 2008, 06:44 PM
Will fly some day
willfly's Avatar
Brampton, ON
Joined Dec 2003
361 Posts
Start with your smallest drill bit. It won't be a bad idea to push a pin through it, to see if it makes to the hole in plywood. Try to keep pin as vertical as possible.
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Old Sep 09, 2008, 03:21 AM
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CANTZ506's Avatar
Brescia, Italy
Joined May 2004
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Quote:
Originally Posted by willfly
... Try to keep pin as vertical as possible.
Or, better, perpendicular to the wing's upper skin.
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Old Sep 10, 2008, 04:42 AM
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Qbert's Avatar
Italy
Joined Jun 2007
48 Posts
I'm working on the fuse and looking for a folding prop spinner.

I need 3.2 shaft diameter and 30 mm base diameter cone. Any suggestions?

In my hobby shop, they sell Graupner ones. They have

1335/20/11 (8x4.5)
1335/23/12 (9x5)

Someone knows the spinner dimensions of these items?
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Old Sep 10, 2008, 05:30 AM
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CANTZ506's Avatar
Brescia, Italy
Joined May 2004
784 Posts
Quote:
Originally Posted by Qbert
I'm working on the fuse and looking for a folding prop spinner.

I need 3.2 shaft diameter and 30 mm base diameter cone. Any suggestions?

In my hobby shop, they sell Graupner ones. They have

1335/20/11 (8x4.5)
1335/23/12 (9x5)

Someone knows the spinner dimensions of these items?
I had the same need and after a bad attempt to change a 3 mm hole into a 3.2, manually , I ordered the smallest spinner with a 3.2mm hole and used its central piece with the 30mm spinner.
Look at www.hobbycity.com.

Piero.
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Old Sep 10, 2008, 05:31 AM
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Joined Dec 2007
55 Posts
Quote:
Originally Posted by Qbert
I'm working on the fuse and looking for a folding prop spinner.

I need 3.2 shaft diameter and 30 mm base diameter cone. Any suggestions?

In my hobby shop, they sell Graupner ones. They have

1335/20/11 (8x4.5)
1335/23/12 (9x5)

Someone knows the spinner dimensions of these items?
I hope that on these links you will find the required infos:
http://www.hobby-lobby.com/camfold.htm

http://shop.lindinger.at/product_inf...ducts_id=22904

http://shop.lindinger.at/product_inf...ducts_id=22905
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Old Sep 10, 2008, 07:16 AM
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Joined Dec 2007
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Quote:
Originally Posted by CANTZ506
I had the same need and after a bad attempt to change a 3 mm hole into a 3.2, manually

Piero.
I also have a 30mm headless spinner with 3.0mm hole, but I can push it to the 3.17mm shaft of the motor.
(ok, the motor have not got electricity yet. )
But if I have to modify, I think I will give throttle to the outrunner and I will refine the spinning shaft with a rasp and polish paper. )
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Old Sep 10, 2008, 07:51 AM
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Italy
Joined Jun 2007
48 Posts
Quote:
Originally Posted by buzziehv
I also have a 30mm headless spinner with 3.0mm hole, but I can push it to the 3.17mm shaft of the motor.
(ok, the motor have not got electricity yet. )
But if I have to modify, I think I will give throttle to the outrunner and I will refine the spinning shaft with a rasp and polish paper. )
Pay attention for that. I fall in that mistake too with bad results: odd hole and waver spinning.

I think the best way is to put the spinner shaft bolt into a driller and take the drill pin fixed, with a grab or a vise for instance. Doing so, the hole should remain in axis. Hope have explained myself!
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Old Sep 10, 2008, 08:05 AM
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Joined Dec 2007
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Quote:
Originally Posted by Qbert
Pay attention for that. I fall in that mistake too with bad results: odd hole and waver spinning.

I think the best way is to put the spinner shaft bolt into a driller and take the drill pin fixed, with a grab or a vise for instance. Doing so, the hole should remain in axis. Hope have explained myself!
I do not want the 3mm dia. hole drill up to 3.17mm.

I want to grind/polish the shaft of the motor from 3.17mm dia. to 3mm dia.

I will mount the motor to a fixed thing and give full throttle to the motor and I will polish the spinning shaft if it is needed. But now it seems, that I can push the 3mm spinner to the 3.17mm shaft massively.
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Old Sep 11, 2008, 03:56 AM
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Joined Dec 2007
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I think I will be the Guiness recorder of asking about the build of Guppy...

I started to build the fins of the Guppy.

In the plan there is a hinge solution of:

_________
___/I____

But I would like to use GWS-style hinges (flexible thin rectangular)

So I prefer this hinge solution as I do not like to glue the hinges to the surface of the fin, but in the middle of the material:

======><======

I think it is not a big deviation from the plan. Am I right or I have weak knowledge of aerodinamics?
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Old Sep 11, 2008, 07:11 AM
Bill Scott
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United Kingdom, Northern Ireland, Belfast
Joined Nov 2002
601 Posts
Quote:
Originally Posted by buzziehv
I think I will be the Guiness recorder of asking about the build of Guppy...

I started to build the fins of the Guppy.

In the plan there is a hinge solution of:

_________
___/I____

But I would like to use GWS-style hinges (flexible thin rectangular)

So I prefer this hinge solution as I do not like to glue the hinges to the surface of the fin, but in the middle of the material:

======><======

I think it is not a big deviation from the plan. Am I right or I have weak knowledge of aerodinamics?

The hinge solution is for the tape type of hinge or using the covering material. No reason central hinging with GWS style wouldn'twork, just bevel the edges accordingly.
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Old Sep 11, 2008, 08:35 AM
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Joined Dec 2007
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Quote:
Originally Posted by billscottuk
The hinge solution is for the tape type of hinge or using the covering material. No reason central hinging with GWS style wouldn't work, just bevel the edges accordingly.
And could you please explain me why central hinging would not work?
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Old Sep 11, 2008, 10:00 AM
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CANTZ506's Avatar
Brescia, Italy
Joined May 2004
784 Posts
Quote:
Originally Posted by buzziehv
And could you please explain me why central hinging would not work?
He said the contrary. It will work!
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