Originally Posted by baldguy

I'm thinking of switching the 2 ribs that the landing gear mounts glue into out of 1/16 ply. I'm a little concerned about the landing loads on balsa ribs. If I don't make a full ply rib I might just make a ply front rib piece for each one.

It ain't of much use making the back part ply too I think. I don't know the exact situation, but normally the front part of the rib and the spar should take the load.

Tom

Originally Posted by baldguy

If I don't make a full ply rib I might just make a ply front rib piece for each one.

Hey but that is already done for you, there are ply doublers one for each rib where retracts mount . In fact I can see it

Building to fly or building to crash?
Unless you have retracts the balsa should be enough if you are sheeting the wings.
A ply dihedral brace behind the spar for the center section is probably enough.
Lighter has less energy to dampen when it does happen to crash.
FWIW...

Also, isn't a beta build suppose to prove the design, if you go modifying it it won't prove the build will it?

RAFster
David

Ooops, yer right, forgot about the ply doublers already laser cut. I gotta get more sleep man!
Beta builds are to prove the design yes, but also to catch any areas that might have been missed in the design. Always build to fly, started with and still am doing lots of freeflight, indoors and out. Some of my beasties weigh about 9 grams, and they're scale!.
Yes, this one will have retracts on the mains for sure.
Baldguy

Also decided not to use the dihedral brace. This panel joint is after the landing gear position, so there will only be flight loads on the wing, and right at this joint there are doubled up 1/16 balsa ribs. After I sheet the wing I'll wrap a layer of glass cloth around the joint before I cover and glass. With the type of flying expected of this model that should be plenty strong enough. Shame about those laser cut ply rib doublers, I was sooooo looking forward to cutting them out on my scroll saw and making those little holes for the retract mount rails to go into!

<<Shame about those laser cut ply rib doublers, I was sooooo looking forward to cutting them out on my scroll saw and making those little holes for the retract mount rails to go into!>>

well you just have to shut your eyes enough so that you can't see the doublers that came with the parts and it is bussines for you . I don't know what the weight penalty is for replacing the balsa ribs with ply , but alternatively you could sandwich two 1/32 ribs together cut cross grain and laminate to get a 1/16ish thick rib that is stronger compared to the 1/16 ribs but ligther compared to 1/16 ply. but obviously feel free to modify at will

Nope, got the laser cut doublers and balsa ribs setting up as we speak! I think they'll be plenty strong once it's all assembled as one unit. Make one piece stronger and just send the stress somewhere else, that's not suppose to have stress. It's a viscous cycle! Parts fit is really good so far, every little hole lines up with every other little hole. It's nice you included the air line holes in the ribs for the retracts.

Originally Posted by baldguy

Parts fit is really good so far, every little hole lines up with every other little hole. It's nice you included the air line holes in the ribs for the retracts.

Plagiarising what you just said... it's nice you thought the holes in the ribs were for the retract air lines . Actually these are for the CF spar that runs in the outer panel and fit in the CF tube of the central wing section hence the difference in the diameter when you compare the holes of the outer wing panel vs central wing panel, BUT if you think the covering you are applying to the wing provides enough structural support, then you can use those holes for the air lines , for example 25g GF with finishing resin can definetly do the job, it is just for people that go for some iron-on fabric that CF spars are more ncessary. so nice to have the same feature been used for different jobs

Okay, so I'm a doofus! Maybe I will use the CF spars, a little extra piece of mind. I did notice the difference in diameters of the holes, but I didn't see any reference to them on the drawings. Was gonna ask you about those before I got too carried away. Just getting all the parts test fitted and any laminating that needs to be done out of the way. I'll have to try and find a source for some CF tubes in the big city this weekend when I'm there.(75mile drive, one way). That's what I get for living in a country the size of Canada!

Here's the center section, showing one of the ribs with the ply(laser cut) laminated to it.

ooops

Hi Craig,
The difference i the position of the holes in the two outer ribs of the central section is another feature that defines the dihedral of the outer panels. enjoy

That's what I figured after looking at the two holes.

Gotta get some CF rods, so the wings are on hold. Started the vertical stab and rudder, only 3 pieces. What do you all think, should I go for 4 channel and put in a working rudder. Don't really think it's worth the extra weight do you?

Wing panels