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Old Mar 17, 2009, 05:04 PM
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ooops....

Last night I reinforced the wing and tonight I tried to loop the glider. It went pretty well and I got more excited...... after another 6 or 7 loops the wing cracked, I was still able to fly (with much more dihedral), but it is in need of repair now.


And I was just getting used to coming back home with an undamaged plane....... I have gotten used to repairing planes while flying (or trying to) 3D for a long period.
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Old Mar 18, 2009, 07:49 AM
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Did it actually break the spar, or just part of the wing panel?

I usually over build my wings when I can as I just know that eventually I will be tempted to loop, and if it will inside loop then you just have to go for the outside loop. I have folded way too many wings in flight.

There has been some mention about "carbon tow" as a means of reinforcing spars. I was wondering if this type of material could be applied here to improve glider wings?

When I have a flat center section to the wing I will build in a carbon arrow shaft. This I know works as I have had one in a Blu Sail for more than 32 hours of flight time with no problems. It reduces the flex alot and is loop proof.

Has anyone attempted to make a foam wing of this length so it will disassemble in the middle for transport?
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Old Mar 18, 2009, 08:03 AM
Jack
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".,.Has anyone attempted to make a foam wing of this length so it will disassemble in the middle for transport?..."

Tony65x55 posted a design for a 96" KFm wing that has a CF tube center joint. It really intrigues me to look at it. I think scaling the Blu Sail II up to 96" wing span for that wing would be a good start for a transportable glider. Here is the post with the plan for the 96" wing:

http://www.rcgroups.com/forums/showp...postcount=2163

A sketch of it:

http://static.rcgroups.com/forums/at...ane%20wing.jpg

and the plan for it:

http://www.rcgroups.com/forums/showa...mentid=1598278

That was posted in the Blu-Baby thread so it did not get built over there and there were no follow up posts on it. I don't know if it was ever build or not.

A search for the guy Tony was talking to there, JimW, may produce some feedback on the wing.

Jack
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Old Mar 18, 2009, 08:53 AM
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No, the spar did not break, hence the reason I could still fly and after landing I actually flew another couple of minutes. It was the wingpanel that broke, right beside a balsa reinforcement.

I should have known that it was not smart to do with this wing. For acro-stuff I should build a new wing from the ground up..... but I have repaired the wing, added another spar inside the wing, some glue to the crack and some duct-tape on the bottom of the wing. The wing has become a lot heavier now but it should still be good for teaching and gently flying around.

With regards to detachable wings, I came across a link of a nice Bird of Time yesterday, that can be fit into a small suitcase for travelling: http://jroger.nuxit.net/berliweb/tykei/page_tykei.htm

have a look for some ideas, even though this was built from balsa, I believe some ot the ideas can be used on foam models as well.
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Old Mar 18, 2009, 08:56 AM
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Jack

If the wing is seperated in the middle for transport this will make a weak spot, if the wing has a center dihedral support. I need to figure out how I could make this as strong as a wing that did not have a break down spot at this point.

Rolland
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Old Mar 18, 2009, 11:27 AM
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Quote:
Originally Posted by jackerbes
".,.Has anyone attempted to make a foam wing of this length so it will disassemble in the middle for transport?..."

Tony65x55 posted a design for a 96" KFm wing that has a CF tube center joint. It really intrigues me to look at it. I think scaling the Blu Sail II up to 96" wing span for that wing would be a good start for a transportable glider. Here is the post with the plan for the 96" wing:

http://www.rcgroups.com/forums/showp...postcount=2163

A sketch of it:

http://static.rcgroups.com/forums/at...ane%20wing.jpg

and the plan for it:

http://www.rcgroups.com/forums/showa...mentid=1598278

That was posted in the Blu-Baby thread so it did not get built over there and there were no follow up posts on it. I don't know if it was ever build or not.

A search for the guy Tony was talking to there, JimW, may produce some feedback on the wing.

Jack

IS this to simple?
Maybe together with some CF tube gliding in to each other.
http://agert.homelinux.org/blog/inde...Wingjoiner.png
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Old Mar 18, 2009, 12:04 PM
Jack
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Rolland wrote:

"..If the wing is seperated in the middle for transport this will make a weak spot, if the wing has a center dihedral support. I need to figure out how I could make this as strong as a wing that did not have a break down spot at this point..."

The wing I posted has two 24" inner panels joined to make a flat 48" center section for the wing. So the joint is flat. Then the outer 24" of the wing has dihedral. That is not a polyhedral wing is it? Not sure what that kind of wing is called.

That plan does not specify the dihedral on the outer sections. How much do you think would be needed for that? For a RET and also for ailerons? I would think that 2" or 3" would be a good start, 2" might work for both RET and ailerons.

Plenty of room for flaps and spoilers on that big a wing.

I can think of a lot of ways to make a good strong wing joint with a threaded coupler that had right and left threads on the ends but you have to have a sort of "lump" for a housing if the wing had dihedral at the center. A flanged type joint would work too, it would have to extend down into the fuseage a little and have a little "humpback" look on top of the wing.

We are foamies! We have some sense of esthetics but if it will fly, we can tolerate some ugliness. And the more fun it is to fly, the more of it we can live with. :>)

Jack
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Old Mar 18, 2009, 12:16 PM
Jack
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Petrik59 wrote:

"..IS this to simple?
Maybe together with some CF tube gliding in to each other..."

No, that is a good start. But it would only strengthen against forces pushing up from the bottom, it would not restrain the wings from lifting and folding upward.

If it had another plate and pegs on the bottom of the wing too, the two plates would work together to resist flexing either up or down. If it was a rubber banded mount with them outside the pegs, that might work pretty well.

Jack
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Old Mar 18, 2009, 01:46 PM
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Could someone post the wing length and chord of the Blu-Sail II?

Someone wants a wing for a different project and this would fit the bill possibly but the starting dimensions aren't listed on the plans.
Thanks.
Mike
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Old Mar 18, 2009, 02:43 PM
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All of the strength in the joiner is in what ever you use for the main pin. aluminum, CF what ever and the way it is attached to the man spar. A sturdy box next to the spar wrapped with CF Tow for strength is as simple as I can come up with. I intend to use aluminum for the main pin.

I think the main reason Duc's wing failed was to much torsional stress. His wing flexes a bunch. Mine flexed but not that much. Eventually the pulling loads on the wing caused the foam to fail. The loads imparted on the center joint of a wing that is this wide require us to reconsider how we build the wing. It is possible that something as simple as a strip of package tape on the underside may have been enough to keep it from failing in that way. A CF sandwich dehidral brace may be needed or maybe even a more involved support structure inside the wing at the center. We are going to have to try some things and figure out a way to make it more durable.

Rob...
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Old Mar 18, 2009, 05:23 PM
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Add a CF tube in one wing half and a CF rod in the other (one or two) and slide them together. If that is not enough let the pegs come out under the wing, make a small hole through the fuse and join with rubber band.
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Old Mar 18, 2009, 05:36 PM
Jack
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Hopalong X wrote:

"..Could someone post the wing length and chord of the Blu-Sail II?..."

Mike,

The attached files have a one inch grid on them, the fine divisions are 1/10th of an inch. That should give you what you want I think.

"..Someone wants a wing for a different project and this would fit the bill possibly but the starting dimensions aren't listed on the plans..."

If you want that same plan scaled to produce a specific wingspan, let me know and I can do that and email it to you.

Jack

P.S. With grids you usually have to count the one inch squares and then zoom in and add the 1/10th of an inch fractions of a square from the ends. I do that and then just use the nearest fraction of that decimal equivalent.

Jack
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Old Mar 18, 2009, 05:56 PM
Rusty
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Wing Join

Quote:
Originally Posted by Rolland Benson
Jack

If the wing is seperated in the middle for transport this will make a weak spot, if the wing has a center dihedral support. I need to figure out how I could make this as strong as a wing that did not have a break down spot at this point.

Rolland
You don't need to join the wing in the centre!
Join it after the dihedral brace and stagger the forces with a diagonal join - just miss the ailerons.

http://www.rcgroups.com/forums/showp...7&postcount=11
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Old Mar 18, 2009, 06:15 PM
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Jack

8x88
Thanks
Mike

Adding them to sticky.
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Old Mar 18, 2009, 07:12 PM
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United States, MI, Parma
Joined Aug 2006
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There have been several ideas on how to make a wing joiner. Unfortunately I am on vacation for about three more weeks before I can start and try one of these ideas. At least it will give some more time to mull this over.

Thanks for all of the input on this!
Rolland
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