[Max]

Now that the bulk of the wing is restored and the engine pods are attached, a little cleanup of the wingtips were required. The tips on both sides were mangled and required rebuilding



I also noticed the wing had a bit of a warp in it. Probably due to all those years in storage. Neverthless, I found that when I applied some torsional load to the wingtip, I was surprised at how flexible the outer panels of the wings were. This is because the outer half of the wing did not have any shear webbing. I misted the wing with water and set it on my bench with shims at the wingtip trailing edge to induce some washout, then added shear webbing to the outer panels. When one side was dry, I did the other in the same fashion



While the wing was drying, I worked on the power system.

Some considerations:

• I want 2 or 3 batteries in parallel.
• Batteries are mounted in the fuse, but the ESC's will be in the wing
• I want a single connector between the ESC's in the wing and the batteries in the fuselage

Why Parallel? Because a parallel feed to 2 ESC's mean both ESC's will have the same voltage to both ESC's from start to finish.
If I use 2 separate batteries one for each ESC and 1 battery goes flat before the other, I will have a potential engine-out situation at the end of a flight

Also, using a parallel system will allow me to monitor the entire system voltage via the OSD. If I used 2 separate systems, I would have to have 2 separate voltage displays on my OSD, one for left motor battery and one for the right motor battery.

Having a single connector simplifies the installation and removal of the wing to the fuselage when assembling and dis-assembling the model.

Here is a shot of the connectors I will be using in this model:
Considerations:

• Batteries in my inventory have both 16 guage and 14 guage leads
• Y connectors come with 16 guage leads
• 60A esc's used in this model use 16 guage leads

I am using a standard Y connector in 16 guage to connect the 2 batteries together. Then the Y feeds a single 14 guage lead that runs to 2 Anderson connectors, that then runs to one of 2 ESC's in 16 guage.

On my Kadet singe engine model, I am already running a G45 motor and 70A ESC using the Y connector in 16 guage. I dont think either segment of the Y connector would see an over-current situation powering 2 G10's on 60A ESC.
Where the Y connector joins a together, the 14 guage lead should be adequate to handle the current.




Here is a shot of the complete power system.
The beauty of the Anderson connectors is that they connect together to form a single connector. The Andersons on the ESC's can both be connected to form a single connector. Same goes for the other end. Now I will only have 1 connection to make for the ESC's when I assemble the plane at the field.

[davidmc36]

Originally Posted by Max

....I found that when I applied some torsional load to the wingtip, I was surprised at how flexible the outer panels of the wings were. This is because the outer half of the wing did not have any shear webbing....

Incredible how much difference the lack of shear webs make. I found this recently with a re-build/completion/heavily modifying project of a Telemaster that I was gifted. The original owner chose to ignore the webs and the wings were like spaghetti. After the webs went in they are solid as a rock.

Actually just got back to making a couple pieces for this, soooooo many things to distract life in general.

http://www.rcgroups.com/forums/showthread.php?t=1737571

I can't wait to see some video of this twin engine machine of yours. I toyed with the idea with the Telemaster. Still not too late to do it actually.

Sorry,

[Max]

Hi Dave. As this project nears completion, I am getting pumped!

I am really hoping this will "fly" as a twin. For what I want it to do, hoping this twin will fly as good as my single-Engine kadet.

The shear webbing seemed to have done the trick. The wing is solid now and the warps that were there before are gone.

I'm liking your thread on your Telemaster. Twin!twin! make it a twin!!

The work continues tonight!!! I will post pics on my progress later.

[OLD PRAIRIE RED NECK]

I suppose this could be done with 2 battery packs in series too. It would mean that the motors would have to be higher rpm with smaller props(disadvantage on that type of plane)but the long motor lead/over current issue would be less of a concern.

Just thinking out loud here!

[Max]

Originally Posted by OLD PRAIRIE RED NECK

I suppose this could be done with 2 battery packs in series too. It would mean that the motors would have to be higher rpm with smaller props(disadvantage on that type of plane)but the long motor lead/over current issue would be less of a concern.

Just thinking out loud here!

The only thing with series is; you need to have identical battery packs. Series is good if you need a 6 cell pack but only have 3 cells on hand. But the limitation of having identical packs is frustrating some times.

With parallel, you can mix and match anything and everything as long as they are the same number of cells

[Max]

I’m getting really pumped at the prospect of getting this plane flying this weekend.

Last night was a marathon of odds and ends to get it ready to cover. I had to stay up just a little past my bed time, but it was worth it! Almost there!!!!!

First was the fitting of the ESC’s into the wing bay. The most logical position to put them in was the section of wing between the main spar and the leading edge in the first bay.


Here is a shot of both ESC’s installed and hooked up.


I considered all kinds of options for accessing the ESC should there be a problem in the future. However, I didn’t really feel like making removable access hatches at this time. The simplest solution is to just cover it up and should the need arise, I can simply cut a patch off the covering off (Preferably the bottom) access the ESC’s and then cover it back up when the work is done.
There is only one problem with having the ESC sit in the wing bay, and that is heat. You can see in this picture that once the ESC is covered over with mylar, the EC will be totally closed in. (You can also see the top sheeting being glued to the engine nacelle) There is nowhere for the heat they produce to go. These ESC’s will need to be cooled.



My solution is simple. I took a strip of balsa and glued it to the front section of the bay where the ESC sits, leaving about 3/8” gap. The balsa simply provides a bonding surface for the covering material. This area in the center will then be cut away to allow air to be rammed into the ESC bay by the props.

I did the same on the bottom, gluing a strip at the rear of the bay closer to the main spar, this time leaving a larger gap between the main spar and the strip of balsa.
Now the air should flow in from the leading edge of that bay, over the ESC’s and escape from a slot at the bottom rear of the bay. Problem solved!

The wings are almost done….
The one thing I really love about my current Kadet is its night flying ability.
However, the cables for the LED’s as well as the Video TX are taped to the outside of the wing. It’s unsightly and its ugly but it works.


For this twin, I thought I would clean it up a little by running the lighting and VTX leads from inside the fuselage. I ran the LED wires from the wing root to the wing tips


I also added a 3/8” tube on one side for me to run the VTX cables

This wing is now ready for covering.


Moving on to the fuselage, there were still some odds and ends to do.
The underside needed a battery access hatch as well as some bottom sheeting.
This plane was originally configured for tricycle landing gear, so I also needed to add a plywood mount for the taildragger landing gear. I salvaged that from an old wreck. Hence the remnants of blue covering


I also installed the servos for the control surfaces. They were originally further up in the fuselage, but I used my vibrating saw to remove the rails ant set them in the rear. This give me more room up front for the FPV gear, OSD battery and night lights battery.


Also in the above picture, you can see where the original trike ar LG mount is. You can just barely see the rear edge of the new plywood mount I added on the far right of the picture. I contemplated removing the old LG mount, but I see no harm in leaving it in.

OK!!!!! Ready to cover!!!

[davidmc36]

Cool, very interested to the the conclusion. That Telemaster I have on the go will be the first time I ran light wiring without the covering on.!! Makes things soooooo much easier.

Do you have any type wing struts?

You stole my rolled up paper idea for wiring tubes!!

[Max]

Hi Dave. No struts. The wings carry 100% of the load. The box design main spar is pretty sturdy. Which is good because I hate the hassle of hooking up struts. Non functional struts you can get rid of, but functional struts are a must. If I had to choose between one design an another and the only difference is functional struts, I would go with the one without

Wing tube- That's the only way to go if you have to make your own. Paper..tape...Done

[bcsaltchucker]

can't wait to see it with the new covering, Max. And the Gopro videos too! Like a bigger better Twinstar. Reminds me of my first RC plane - a Goldberg Eagle 63, in 1980.

I would love to build a large scale c172 some day. Maybe with some non scale dihedral though, like the Kadet. But scale interior and cam inside.

What OSD/autopilot are you going to run in it?

[Max]

Originally Posted by bcsaltchucker

can't wait to see it with the new covering, Max. And the Gopro videos too! Like a bigger better Twinstar. Reminds me of my first RC plane - a Goldberg Eagle 63, in 1980.

I've always had my eye on the twinstar but found it a bit too tiny for a good FPV platform. I think this will suit my needs a lot better. Sure hope it flies as nice as the original Kadet. BTW, on the same subject of "good FPV flier", I think I am going to retire the Bixler. Last time I flew it, it flew like junk. It was a breezy day and the plane flew like crap. Bixler is good for calm days but not much else. Cant enjoy a good FPV ride when you are getting thrown all over the sky!!

I will be covering like a madman tonight. I want to fly tomorrow!!! I may not have all the FPV gear installed by tomorrows maiden. If I do, great. If not, I wont worry about it. But I will try to get the Gopro mounted for some videos evenif I dont have the FPV gear setup and working.

Originally Posted by bcsaltchucker

I would love to build a large scale c172 some day. Maybe with some non scale dihedral though, like the Kadet. But scale interior and cam inside.

Oh, that would be sweet. A nice scale job with pan/tilt would be the ultimate in FPV realism. I still want to do that with my FPV mustang!

Originally Posted by bcsaltchucker

What OSD/autopilot are you going to run in it?

The only one I love for its simplicity, ease of use and reliability; Dragon OSD (DOSD). It has never failed me yet and has worked when things bugger up and the only thing between you and a lost plane is the DOSD. I love it and wont use anything else now