Project Rays - Manta - Page 13 - RC Groups
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Jul 10, 2008, 08:57 PM
Where'd The Wise Men Go?!?
AC5FF's Avatar
Would love a set of the plans! Instructions come w/ it ?? LOL
Would also love to see some build progress photos
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Jul 10, 2008, 10:28 PM
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Geode's Avatar

Manta Builders

Here is a few Mantas and derivatives ..... Hope you enjoy.

Other than Rendy's and mine, there are a few more in the US.

Czech -


Polish Forum - Manta 1m


Last edited by Geode; Jul 10, 2008 at 10:40 PM.
Jul 16, 2008, 05:00 AM
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geodesic wing construction

HI geode,

finally getting around to building a 40 inch glider based on your geodesic wing construction ideas,i'm using frans bals mini plans and a geodesic wing instead of solid balsa wing like in his plans,would you think the spacing of the wings ribs would work out ok if i kept them the same size as the 34 inch bumblebees spacings or would you increase the dimensions to compensate for the wings extra length?and finally would i be better off having a solid leading edge say an inch back and having carbon fibre spars incorporated into that or having a thin leading edge and the spar system as used in the bumblebee?

thanks chris
Jul 16, 2008, 11:14 AM
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Geode's Avatar
That's a good starting point. There are a few other parameters you might want to consider, Dbox, spar, balsa density, ......, when design/building your wing.

I used heavier balsa on the outter ribs to compensate for the thinner airfoil near wing tips. I would recommend a conventional build-up Dbox over solid balsa Dbox for better weight/strength ratio.

Have fun building,
Jul 20, 2008, 04:15 PM
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Hi Geode,

I reviewed your plan.
I converted the measures to mm, and I made the list of the materials

What size of carbon tube did you use for the fuselage?

What I missing from your plan the position angle (I don't know is this the right word for it) of the wing.

Jul 20, 2008, 07:17 PM
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Geode's Avatar
Hi Vince,

Great to hear that you're ready to roll.

For tail boom, any SGII compatible boom will do the job (0.64" OD tapering to 0.32" OD, weight ~16g).

I use 0 degree for wing to boom angle to minimize frontal area. Since I use full flying tail, I also set the wing to tail angle to zero degree and then fine tuning at field.
Jul 21, 2008, 03:23 PM
Registered User
Hi Geode,

Thanks for the info.
I have another question
On the drawing there are 15 wing ribs, but on the top view of the I see only 12.
The last 3 rib only a "template" wich helps to create the profile of the wing?
Or if not where is the place?

Sorry, for this many question but it's easier to ask it

Otherwise, I will use 12 mm carbon tube for fuselage, It will be enough strength I think, it will looks a little bit uglyier, than the tapering, but I can purchase only this type unfortunatelly.

Please, can you tell me how big movements do the control surfaces have?
And where is the Cg? In the 1/3 part of the wing from the leading edge?

A good news:
My clubmates saw the drawing of the manta, they infected too soo simultaneously 3 manta will be building, whole little armada.
Jul 21, 2008, 03:36 PM
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I reviewed the topic and I found the answer for the Cg position
Jul 21, 2008, 11:52 PM
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Geode's Avatar
That's correct. The last 3 ribs are for reference only.
As for control throw, SGII is a good reference to start with.

Have fun building,
Jul 26, 2008, 01:01 PM
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Hi Geode,

Well the things are rollin.
A half is already my wing.

I would like mount a "throwing thorn" or launch peg on the wing.
What do you think where is the best place it?

In my opinion somewhere near the spar at the end of the wing, because that is the strongest part of the wing. It is not too comfortable to my hand but I'm afraid to mount somewhere.

Have anybody a launch peg on Manta?
Jul 26, 2008, 02:36 PM
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Nice Job!

"In my opinion somewhere near the spar at the end of the wing, because that is the strongest part of the wing"

I think You're right.

What's the weight of Your half wing? I've sanded out the aileron from one balsa block and it became very heavy, 22 gramms :S Maybe I should make another one.
Jul 26, 2008, 09:23 PM
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Geode's Avatar
Nice jobs!

Throwing peg..... If you decide to move it away from spar, do remember to add some hard spot to support the peg.

Smash, I see some diagonal cuts on the aileron and rib. Is that something for aileron control? RDS?
Jul 27, 2008, 03:55 AM
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Hello Geode!

Yes, yes it will be! But now just markings not cuts. You've got very good eyes

The half wing is 70 gramms now. I can't make the aileron lighter :S
Jul 27, 2008, 05:53 AM
Registered User
Hi Everyone,

Well the plane builded by my clubmate, not by me, because I don't have time to build unfortunatelly.
I'm just decide in the construction's question and I get the components, which we need.
But today I will go to see how is the things are going and I weight it for you.

I will use bigger accu and a normal Futaba receiver, so I have to design a new a little bigger pod.
What are the experiences?
Usually nose or tail heavier the Manta when it is ready?

I ask this because I wouldn't like to give too much weight to balance it, and I will care this during the design of the pod.
Jul 27, 2008, 11:22 AM
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Geode's Avatar
Originally Posted by Smash
Hello Geode!

Yes, yes it will be! But now just markings not cuts. You've got very good eyes

The half wing is 70 gramms now. I can't make the aileron lighter :S

As for aileron, I don't have a perfect solution other than find some light weight balsa.

Howevre, is the wing strong enough tortionally? If so, a few grams might be saved by adding holes to the under of the Dbox sheeting.

Also, if there is room to thin down the aileron a littile bit more (a small distortion on airfoil is acceptable), this could also save a few grams too.

BTW, I just love those nicely shaped and organized holes on aileron. They look so neat and they blend in the RDS perfectly. Keep us posted on your progress.

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