Ridge Runt Evo - Build Thread Comments

[Billy Eister]

Here are photos of the two planes.
The glider weight is 277 grams without the battery and the power glider is 433 grams with battery. Need to find tune the nose weight for proper C.G. I didn't see that on the plans.
The other thing I did was use a smaller thickness magnet. I hope to test fly the power glider Wednesday.
Great design, enjoyed building them.
Thanks Wayne and team.

 

[Warthog]

Memories of having to rip apart my JW last year to get to bad battery say otherwise!

 

[gnichola]

One warning is to always stop the end of it when your building session is done (as you can see I've done here with a t-pin). Otherwise, in certain conditions, I guess caplillary action or something can take hold, and the CA will just start leaking out by itself (ask me how I know).

I believe this happens due to temperature and the air in the bottle expanding. The same thing happens to the pump bottles of bath products in our shower. When the temp goes way up, they start to ooze.

 

[Wayne]

We have yet to hear a report of an Orbit servo failing. We have sold a few thousand of them. We have had guys crash DS models into the ground at over 100 mph and they tossed the plane but kept the servos for the new model. I'm not saying they are the best servo in the world, but they are not the typical junk we see included with ARFs.

With this said, this is the second request for a removable servo solution for the ailerons. We will be looking into this in the future.

 

[Tahoed]

We have yet to hear a report of an Orbit servo failing. We have sold a few thousand of them. We have had guys crash DS models into the ground at over 100 mph and they tossed the plane but kept the servos for the new model. I'm not saying they are the best servo in the world, but they are not the typical junk we see included with ARFs.

With this said, this is the second request for a removable servo solution for the ailerons. We will be looking into this in the future.

Can we run these on a 1S li-ion??

 

[Warthog]

My wing is mostly assembled, but I'm still kinda concerned about its torsional rigidity (see video, below). It seems quite floppy, even compared to the original Ridge Runt (granted, mine is covered, which does help). I've been thinking about adding 1/16" balsa vertical grain shear webs, much like the original Runt had on the spars between most of the bays.

 

[Tahoed]

Once you cover it, you'll find the additional shear webs are unnecessary.

 

[Hoqiam]

Vertical Shear Webs will do nothing to control twist/torsion except to add weight! The spar shear web is only handling spanwise shear due to bending!
Diagonal ribs or heavy covering (balsa skin/doped fabric etc.) will add torsional stiffness. Two main spars can improve torsion due to "differential bending".
This is because when you twist the wing one spar is forced to bend up and the other is forced to bend down. The degree of stiffness is controlled by both
the stiffness of the spars and the separation distance between them.

Tom

 

[Wayne]

Don't worry guys, when you cover the wing you will find it becomes plenty stiff in torsion. It will not be an issue. The goal with the wood wing is to keep the plane light and simple. We will also be offering a foam core wing kit for it in the future using a little faster airfoil.

People love to debate the grain orientation of a shear web, and basically vertical or horizontal really makes no difference, and in the case of this wing would make zero difference. i'm told the proper grain orientation is with the grain 45° to the bending motion. Something none of us have probably seen in the hobby due to the added trouble and expense.

If one wanted to improve the torsional stiffness, look at our AH-100 wing. That wing has intercostals (diagonal supports) for exactly that reason. The rest of the AH-100 wing is basically the same construction as the Ridge Runt Evo. Does the AH-100 need this added structure? I don't know as we never flew it without them, but I suspect it would be fine without as long as you use a thicker covering like Oracover and kept it out of terminal dives. But they are pretty, so why not?

 

[Wayne]

Was thinking about this some more an thought maybe I should add a bit more to this subject.

When I reported the AUW of the Ridge Runt Evo some seemed to question if that weight was even possible. I have heard that with many of my glider builds, and I will add that I am not a great builder, I'm not doing anything special to add lightness, but I do avoid things that are just going to add weight.

My goal is to never offer a plane that can be damaged just from flying it. I want to be confident that the plane has plenty of structure to survive any sort of flying I may throw at it at its intended weight. And I think this is very normal for any models in the hobby. There are always some exceptions to rules, but you know when you are getting into that zone of super lights chasing a special goal (think some thermal models).

The spars in our designs are VERY strong. I actually have custom carbon strips in the works for future projects to save a bit of wing weight. We could easily cut the carbon weight in half on the Ridge Runt.

I love to see people make improvements, but will warn to keep an eye towards being lighter. This even applies to lead sleds.

 

[Warthog]

I guess I'll take your word for it and see how it is after covering.

FWIW, I thought the point of the vertical balsa shear webs was to tie the upper and lower spar caps together so they can't twist wrt each other. With regard to the 45 degree thing, I have an old and broken F3F plane (a Sting), where you can see that the upper and lower caps are tied together with a layer of fiberglass on the bias (so 45 degrees), over a foam core.

 

[Wayne]

I have a good start on the build manual now. Been cleaning up the text and adding some content here and there. More to go.

 

[Hoqiam]

All---my post was in no way trying to be down on the design of the Runt! I was trying to explain that adding vertical shear
webs was not going help torsional stiffness. Many model aircraft have no main spar at all, they have several small spanwise
stringers in the upper and lower outer surfaces of the ribs to carry the spanwise wing loads.

Tom

 

[Wayne]

Hey guys - My comments were only meant to shine some light on keeping the plane light. I don't think I did a very good job at doing so. I had a few things going on this morning when I wrote it. Sorry.

 

[Hoqiam]

No problem! We are all sailing the same boat!

 

[Wayne]

Warning - When seeking help on your build we do not suggest you try to work with this individual:

His work is subpar, here is an example of what you can expect:

Clearly he has not idea how a plane even works.

Dang cute though. New parts ar on the way.

We should have included a dog toy.

 

[Tahoed]

I think it was a QC issue...


.

 

[Wayne]

I think it was QC testing.

Build manual has been updated to where my build is currently. Just setting up the electronics, setting the CG and some hinging and some color trim.. and stickers. and...

 

[Warthog]

Did I do something wrong here: I was under the impression the trailing edge would sit flush with the edge of the rear decking? I've re-measured everything, and everything is spot on with regards to the plans, and the rear decking goes up to the peak of the wing saddle as the instructions indicate.

Not that it's a big deal, as I can always add a bit more planking behind the wing...just want to be sure I didn't make some gross error.

 

[Tahoed]

Did I do something wrong here: I was under the impression the trailing edge would sit flush with the edge of the rear decking? I've re-measured everything, and everything is spot on with regards to the plans, and the rear decking goes up to the peak of the wing saddle as the instructions indicate.

Not that it's a big deal, as I can always add a bit more planking behind the wing...just want to be sure I didn't make some gross error.

That's the way mine came out too. See my comment in post #10.