EMS Black Edition Arcus - rehab and refresh

[Steve P]

Just a quick "assembly" thread and place to store off a few photos as I refresh a gorgeous carbon Arcus. Plan is for it to fly at Black Dirt.

Specs:
Scale: 1:3.75 = 5.33 meter span
Servos: Mostly Savox 1256TGs with Futaba 3172s on ailerons, and Hitec 7955TG on the SLS boom. 15 channels in total.
Motor: Torcman 350-22, Jeti Pro Spin 77, 16x10
Rx Power: 2x 2S 2250 mAh LiPo
Motor Power: 2x 3S 5000 mAh LiPo (6S series)
PowerBox Competition SRS
2x JR DMSS Infinity receivers with 6 remotes in total
JR 28x (will go over the CORE this winter w/ two 26D receivers)

I've always loved the EMS products and in general have come to prefer the 5.3-6 meter span sailplanes. This checks all the boxes.

It was originally imported from EMS in 2014 (complete build/servo/SLS install done by them), had a half dozen flights and has been packed away since. I spoke with Ralf at EMS about set-up of the plane, the SLS and powering the motor (could push it to 8S, but we'll start with his recommendation of 6S).

It was the classic EMS pink (purple? Man- genta?) and black graphics scheme. Eeew. The cockpit was a rat's nest of wiring from the owner's power install and radio setup (Spektrum 9ch w/ +8 expander) and Emcotec switches all nested in a bundle on top of the retract. That all came out and PowerBox went in with all the wiring cleaned up. I refinished the cockpit pan and repainted the binnacles and refaced gauges.

I'm getting more and more bored with white sailplanes! So, after seeing a full scale with circles on the nose for anti-collision, I decided to see how extensively I could abuse the circle concept. Callie was up for the idea. It's called "Emmental" (Swiss Cheese). And, I decided to take it over from D registration to HB. Who can guess why the reg number is 1183?

Here you go. Radio and motor install done, graphics started...






2 Rx batteries go left and right in the nose.
The motor batteries go beneath the seat pan side by side.

[porcia83]

Wow...that looks fantastic. LOVE the livery on it...very nice! Hope to see it in the air soon.

[Steve P]

Final balance, SLS test and ready for Black Dirt Aero Tow...

[Swiss1]

You have gone Dotty Steve
That tail Cross is not in Compliance Sir
Maybe if you removed one dot at the end of each bar, it could pass

Jeremy
SCCAAA TT TN

[Steve P]

A good lesson learned. Don’t get cocky when you’re low and downwind thinking you can scratch because eventually your SLS will save the day. The batteries have to agree that they have enough left!

So, I managed to have an off field landing at Salem last month — with the SLS extended of course (or perhaps caught up in the doors which occasionally happens). I thought I killed the unit but today I dug in and took it all apart to find all I managed to do was bust the arm and subsequently jam everything up so it seemed like it was profoundly broken. It’s fine. Still not in love with how it all functions that has nothing to do with the latest incident rather its technological age.

When life gives you plastic arms make metal ones. H9 to the rescue.

PS This sailplane is a joy to fly! Loves the extra weight it carries. Highly recommended! Ralf will hook you up!

[pete914]

SLS headaches, there seems to always be something going wrong with a sailplane's SLS system. That goes for full-scale too..hahah
Please do a thread with tips on your vinyl work Steve, it's incredible!

[Steve P]

Yeah, like retracts don't offer us enough frustration and mental abuse. Let's add another whirling mess of dysfunction on top of the fuselage too! ;-)

[Steve P]

Just using the site to store off a couple photos. These days the Arcus sports and EDF running on 12S. I had questions about how the EDF mounts without a firewall, but I can’t remember from who??

The EDF mounts to the top of the retract. The rear mount goes over the rear crossbar of the retract and slides forward while the front clips into two studs added to the interior sides of the retract. Pop two simple clips and the whole unit slides out. One of the studs fell out at Cumberland (I flew it anyway) and once at home I reinstalled with threadlocker.

Here, while upside down, you can see how the rear of the mount would key over the crossbar...



And the front attachments that go over studs and are secured with simple spring clips....



How one squeezes 12s into a rather tight fuselage. Three 4S 6000 mAh packs...

[Steve P]

Arcus oops! Everything happens for a reason. Sometimes the reason is that you’re stupid and make bad decisions.

In this case, I tried to pop the Arcus off the ground a little bit early on tow. Guess who caught the right tip in the grass and spun the sailplane?

The damage was limited to the fuselage. Carrying 12S 6000 mAh plus two receiver packs and a strobe pack in the canopy area means lots of weight up front. When the nose came around, a stress crack formed in the side of the forward fuselage… that area actually bent, capturing the canopy frame over the edge of the fuselage. This required carefully peeling the canopy clear from the side of frame I could then pry the frame back up and over without risking cracking the canopy clear. Of course these ugly spins on t-tail gliders meant the elevator saddle broke. It also opened up the seam in the vertical.

The repairs are all pretty straightforward. First, repairing the saddle. It all went back in place perfectly and was secured with Hysol HP120 and allowed to fully cure. When I’ve gone through this in the past I also reinforce the area. In this case, the next step was a layer of carbon weave topped with a layer of fiberglass weave. The bottom of the elevator is taped off with duct tape that is waxed several times. The mounting bolts are lubricated with white lithium grease and run in and out of the mounts a few times to transfer the lubricant. The cloth is then wetted out and the elevator bolted in place.





The interior crack is also a basic lamination repair. In this case, two layers of fiberglass with a layer of carbon sandwiched between. I used a piece of waxed mylar weighted to make certain the patch adhered fully to the fuselage interior. Once the thinned HP120 had cured (when you have insane epoxy, why not use it), the mylar popped right off for a perfect surface and the patch was painted out with semi gloss black to match the rest of the interior. Once the equipment is back it place, it disappears.





Finally, reattach the canopy clear to the frame with Goop.



All that remains is very minor white paint touch up paint a heck of a lot of rubbing compound and refining to blend.

[mlachow]

Do you use goop straight on the canopy or do you thin it some.

[Steve P]

I use a thin mixing stick to wipe it on the area full strength. A little goes a long way.