Ridge Runt Evo - Build Thread Comments

[Wayne]

Here are some photos from Konrad using some bad stock:

 

[Warthog]

I finally got around to de-trailing edging and re-trailing edging my wing. I tried most of the techniques to straighten the new TE's. Both the alcohol and ammonia methods didn't take. The slice method worked pretty well on one of them, but the other refused to straighten out fully. Finally I just resorted to facing the front with 1/32" balsa, and then I sanded the curve out of both the front and the back. It turned out pretty well, though.

 

[mjgillen]

Well, three months later I am back to the bench with the RRE. My plan is to complete by the end of this month. Here's where I am right now. The fuse is coming along and I am using Titebond so taking my time on that. While the glue is setting up I am working on the wing.

 

[mjgillen]

I noticed that the shear web and ribs line up nicely with the plans however the sub trailing edge does not. It starts out in alignment at rib #1 but by the time it gets to #11 its about an 1/8" off. I am guessing I don't need to worry about this right? Just want to confirm before I glue it all up.

Rib #1:

Rib #10

 

[Warthog]

I noticed that the shear web and ribs line up nicely with the plans however the sub trailing edge does not. It starts out in alignment at rib #1 but by the time it gets to #11 its about an 1/8" off. I am guessing I don't need to worry about this right? Just want to confirm before I glue it all up.

I think it was a known issue with the plans early on, but it doesn't really make a difference when you build it. Everything aligns itself.

 

[mjgillen]

Thanks for the quick reply! I’m going to glue it now…

 

[Wayne]

Yeah, that was an issue with the length calibration on our large format printer. Didn't even know they had a calibration for that. We had been chasing that issue for a while. We knew our drawings were correct, but they would not output correctly.

Titebond - It is only recommended at wood to wood connections. Plastic to wood and carbon to wood needs to be thin CA. Tittebond has not been tested but pretty sure it would make a very poor glue with these other materials.

 

[mjgillen]

Got it Wayne only used titebond on the bottom of the fuse. Reading and carefully following your build instructions.

Understand about the large format printers. I hear they can be finicky.

Enjoying the build and will keep posting.

Michael

 

[mjgillen]

Another question: I'm working on the other side of the wing. Is there a dihedral in the wing? The half completed wing does not lay flat. If no dihedral I will have to see why and fix it.

Thanks,
Michael

 

[MBR]

Another question: I'm working on the other side of the wing. Is there a dihedral in the wing? The half completed wing does not lay flat. If no dihedral I will have to see why and fix it.

Thanks,
Michael

I believe the center wing jig sets your dihedral, wing halves get built flat.

 

[mjgillen]

Ah that makes sense. The left half is flat however when building the right half, flat on the board, the left half rises a small bit. I’ll glue it up tomorrow. Thank you!

 

[Wayne]

We have flown the electric.

Emax motor, 7x4 prop, servo aft mounted under the wing.

Flew her with a 3S 850 battery, and needed some nose weight to make CG. A 1300 3S makes perfect CG with the battery under the canopy, no need to slip past the leading edge bulkhead, so the elevator servo could move forward with the reverse elevator setup we had originally considered.

We will be addressing electronics cooling with a turbo spinner and some holes in the firewall as we have NO cooling and things got warmer than we would like.

In terms of performance, Jarron tried to rip the wings off of her with heard elevator pulls at full throttle and no issues. I think it is a good sign when Jarron says "Darn it, now I need to build one of these for myself." She looks really good in the air and offers good sporty flight. She has a pretty wide speed range as an electric. Quick enough that I was concerned we may develop some wing flutter, but we could not get any flutter out of her.

We did have an issue though. This build had the mistaken small ailerons on it, and they were twisting at high speed giving poor roll control at the top speed. This may improve with the correct aileron stock, but I suspect we will need to address the torsional stiffness. Maybe a 1/64" plywood sheet on the bottom of the aileron, or some carbon running through the aileron at a slight angle. More testing on this is needed. This is only an issue with the high speed flight. (Our balsa is too darn good and light. Heavy balsa would cure the issue.)

 

[mjgillen]

More photos of my (slow) progress:

Rearranged the plans to do the other side:

Both sides of the wing are done. Aileron pieces cut and glued in. Servo covers glued in. Both wing tips.
Ready for sanding.

Fuse is also done with nose cone and canopy. My canopy is not great but it'll work.
Ready for sanding.

Done sanding

I am going to fit the wing onto the fuse and connect the controls up before I cover. Just want to make sure there's nothing hiding that I missed. Then I will start covering the wing first.

Michael

 

[Wayne]

Why the missing leading edge material in the center of the wing?

The canopy looks like it is pushed back a little. The top fit looks very nice, but the side is a little gappy. Are the magnets holding well? You can add some scrap balsa to the front of the side to close up the gap. A little thin CA and some sanding should get you there.

 

[mjgillen]

Why the missing leading edge material in the center of the wing?

Yeah I mis-read the plans and thought I had to leave space for the carbon pin. I'll fix that before I cover the wing.

 

[Warthog]

This build had the mistaken small ailerons on it, and they were twisting at high speed giving poor roll control at the top speed. This may improve with the correct aileron stock, but I suspect we will need to address the torsional stiffness. Maybe a 1/64" plywood sheet on the bottom of the aileron, or some carbon running through the aileron at a slight angle. More testing on this is needed. This is only an issue with the high speed flight. (Our balsa is too darn good and light. Heavy balsa would cure the issue.)

FWIW, the larger sized aileron stock I was sent varied quite a bit in stiffness between the two. I'm not sure I'll ever fly it fast enough to matter, but I guess we will see.

 

[mjgillen]

I'm trying not to make any more mistakes on this build so I am asking what is the proper way to connect the control rods to the control horns both on the control surfaces and at the servo? The kit came with wires with z-bends on one end for the ailerons so that just leaves one end to consider. The elevator is a mystery to me I have not used this hookup before. Is there an Aloft part I need to buy?

Here are a couple of pictures of progress today. I just gently screwed on the stab to see how it looked. Possible placement of the elevator control horn.

Going to cover the wing next.

Michael

 

[Wayne]

For the elevator you use a simple 90 degree bend. This allows you to remove the elevator for transport. A Z-bend at the servo end works well. That's just me, I like Z bends. If you like, you can use a clevis or an EZ connector at the servo ends, but the bends are pretty darn easy and take up less space. I hate messing around with EZ connectors.

Hmm, I see we did not show details for this in the manual! Will get that sorted out. Will post up some photos in the morning.

 

[mjgillen]

Thanks Wayne, I will try your suggestions!

For the servo in the fuse I used the regular rubber grommets and brass inserts, screwed right into the servo tray.

 

[Wayne]

No need for the rubber grommets and brass inserts, those are left over from the nitro vibration days.