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Old Mar 02, 2010, 07:22 AM
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Originally Posted by toyhatsu View Post
Not sure what to do about spars. Was thinking about tapering plywood with flat carbon top and bottom caps to make an "I" beam. I don't know about the weight though as compared to something else. Would be very strong I think. Bill Steven's of Steven's Aero could laser me some out of ply.
3/16" dowel in "A" frame could work (Home Depot/Lowes). The cross member of the "A" could be flat plywood installed from the bottom. I am using the newer white gorilla glue. I like the tentacles it sends into the foam.
For mine I am putting 1/8" fiberglass rod in "A" frame as an experiment (Goodwinds Kites). I used the wood dowel on a Titan. It is very stiff.

Fiberglass rod is 20% heavier than the dowel however more glue is needed for the dowel because of the size. Weight for weight possibly the same. Fiberglass rod is easier to install because of its smaller size.

I am using Lee's recommended hobby wheel collar on a soldering iron. The wheel collar gets hot so one needs to run it on top of a guide like a metal ruler. The technique makes a great straight cut for the dowel or fiberglass rod.

I don't think the for the front spar or top of the "A" frame needs to have the right and left pieces connected. I believe the front spar is only to stiffen the expanse of the wing and not offer the same support of the center of the wing like the cross member of the "A" frame.

C
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Old Mar 03, 2010, 12:47 PM
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Originally Posted by toyhatsu View Post
Not sure what to do about spars. Was thinking about tapering plywood with flat carbon top and bottom caps to make an "I" beam. I don't know about the weight though as compared to something else. Would be very strong I think. Bill Steven's of Steven's Aero could laser me some out of ply.

For the front spars use the 3/16" round dowels top and bottom and top and bottom for the cross member too. Cost less than $4 at Lowes or Home Depot. It would be very stiff.

The cross member spar could also be just a 3/16" wide piece of lumber or plywood about 1/2" in height spanning about 18" installed from the bottom. That would be easiest. May want to be sure grain is vertical for the lumber piece.
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Old Mar 03, 2010, 08:03 PM
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I posted a Q on the Titan board about having a twin motor version. Looking at the GR, I think this would be a better candidate to try it out due to the longer chord/root. What do you think Lee?...
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Old Mar 03, 2010, 09:12 PM
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Originally Posted by scootty83 View Post
I posted a Q on the Titan board about having a twin motor version. Looking at the GR, I think this would be a better candidate to try it out due to the longer chord/root. What do you think Lee?...
I put an answer there:

It all depends on why you want twin motors.

This is a bigger plane and would be a candidate for that type of experimentation but it isn't as easy as it may seem.

I think the problems with a twin motor such as needing a two ESCs and making sure your battery can handle double amps and trimming the plane make the twin motor more of a problem than an answer.
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Old Mar 03, 2010, 09:18 PM
Lee
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I forgot to comment on the hybrid fins.

I like the finless design. The plane did fly predictably with the drag tip design but would yaw coming out of rolls and with speed transition. I had some small fins in my box and noticed they fit the flat tip on the outside of the wing so I taped them on. Even though they are very small they do make a significant difference even though they only rise 2" above the airfoil.

For those of you doing beta testing you might want to give it a try.
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Old Mar 04, 2010, 01:13 AM
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Any videos yet? I plan to get one in the not so distant future. How does it fly compared to the Titan? Has the carbon fiber spar reinforcement issue been hammered out yet? Does the double "A" reinforcement seem to bee the best one to use?

For those who wonder how to create cool designs or patterns on their laminated planes, I have been experimenting with permanent markers on the laminate. The laminate loves the markers. I have yet to test it on an actual plane and see how well it stands up to combat rubs and belly landings. But, so far it seems to be a winner. Its very light weight, and if you can draw nicely, your design pattern can look sweet!
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Old Mar 04, 2010, 06:50 AM
Lee
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Originally Posted by scootty83 View Post
Any videos yet? I plan to get one in the not so distant future. How does it fly compared to the Titan? Has the carbon fiber spar reinforcement issue been hammered out yet? Does the double "A" reinforcement seem to bee the best one to use?

For those who wonder how to create cool designs or patterns on their laminated planes, I have been experimenting with permanent markers on the laminate. The laminate loves the markers. I have yet to test it on an actual plane and see how well it stands up to combat rubs and belly landings. But, so far it seems to be a winner. Its very light weight, and if you can draw nicely, your design pattern can look sweet!
Our weather has not been very good lately but I am planning on shooting some slope and park flying with both the Grim Reaper and Titan as soon as we get some clear skies.

I have gone back to putting the spars in a pattern that makes a letter "A" shaped layout on both the top and bottom of the wing. I have put big motors and batteries in them and I have taken them into combat and done death dives and hard loops over and over trying to break them. I have used three different kinds of spars, spruce, fiberglass and flat carbon. All of the planes are so stiff they feel like they are made of fiberglass. We have had no flutter and no breakage.

The permanent marker is something I have used before. I used to use the marker to outline other trim to get a bold boarder look to separate colors.

Post some pictures of your finished project and let us know if it fades. I was thinking that it might be interesting to try it on the foam before lamination too.

Lee
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Old Mar 04, 2010, 12:44 PM
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Why use CA glue for the shock cord and spars and not hot glue?
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Old Mar 04, 2010, 12:47 PM
Lee
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Why use CA glue for the shock cord and spars and not hot glue?
It adds too much weight. You have to figure it may be a glue joint 14 feet long. There is also a problem because the hot tip on the glue gun distorts the shape of the foam when you push it into the cut line to insert the glue.

I do use the hot glue on round spars. but not on the flat carbon.

L
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Old Mar 04, 2010, 01:09 PM
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I want 1/8" hot wired spar cut outs on my next CrashTest plane. Then it will only take an hour to build. What about it Lee?
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Old Mar 04, 2010, 01:37 PM
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I want 1/8" hot wired spar cut outs on my next CrashTest plane. Then it will only take an hour to build. What about it Lee?
How much do you want to pay?
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Old Mar 04, 2010, 01:50 PM
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I am certain you have a CNC cutter. Right? Now that the spar deal has been settled...I think a spar cutout should be part of the big planes. Send them out with 1/8" fiberglass and cutouts or foam only no spar cutouts.

I will pay mega $$
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Old Mar 05, 2010, 01:12 AM
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I'll second the request for 1/8" fiberglass and spar cutout package.

Vince
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Old Mar 05, 2010, 07:44 AM
Lee
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The spars are angled is such a way that you can't cut them on a CNC. I have heard of some people cutting them with a Dremel.

The soldering iron is easy to do but it takes enough time it needs to be done by the builder, plus once you get it down you will find it is a skill that you will use over and over in building and repair.

If you want the easiest way use the flat carbon in the double A-frame pattern. It is the easiest to do.
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