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Dec 23, 2015, 12:34 PM
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Build Log

Eagle 3.6 SUSA


I'm building a new Eagle 3.6 from the good folks at Soaring USA. Annette and Alex are a pleasure to work with. I always check RC groups for build info and didn't find much, so I'll put this one out there. There is an excellent similar build log by Rob Glover for the AVA Pro, I used some of Rob's (Bubba's) tips with his permission. You can find his build log here: https://www.rcgroups.com/forums/show....php?t=1336105.

I also received advice from Ed Stewart who kindly sent some pictures along that will be included with his permission.

Paul Naton's "F3X Building Clinic" is an excellent source of information. I've built quite a number of gliders, but I always seem to find useful information in his videos.

By way of calibration, I've been playing with toy airplanes for over 50 years on and off. I'm a level IV LSF and have stumbled into wood at the NATS a couple of times. I had the privilege of being a classroom teacher for 37 years. Now retired: you can take the teacher out of the classroom, but....

This build log is kind of a "Cliff Notes" version of Rob's excellent log, modified for the Eagle. Let me also disabuse you of thinking that the build has happened in the logical step by step method in a neat shop as the log suggests. I fiddle with things out of the presented order and make quite a mess as things move along.
Last edited by Barry Andersen; Dec 30, 2015 at 01:12 PM.
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Dec 23, 2015, 01:00 PM
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Spoilers


Generally no fun to get things working right in cramped space. I've always used a solid linkage in the past but Ed Stewart convinced me to try a system with a lever and magnet. So, simple and works great. The kit comes with parts to make a solid link system if you're so inclined.

I used a tiny square very strong magnet, straight from the fridge. I found a nice little bracket that's got a bit of adjustment up and down, at Lowe's. They're in the hardware section in the pull out drawers with screws and odd fasteners. I think on the right side.
Last edited by Barry Andersen; Jan 01, 2016 at 11:41 AM. Reason: add picture
Dec 23, 2015, 09:31 PM
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Mechanical spoiler connection


The kit comes with hardware to make a fixed wire connection.
Dec 24, 2015, 11:30 AM
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Great buy on your part


congrats on getting a really great flying model.

I will post you some of the pictures and info i have used to build mine.
https://www.rcgroups.com/forums/show....php?t=1964231
https://www.rcgroups.com/forums/show....php?t=2061485

Right off the bat -
- consider using smaller mg micro servos like JR DS390 or MKS or any servo combo that will allow you to put them side by side. Space runs out real quick.
- Standard 4 'AA' cell eneloop or nimh will fit and work just fine
- The AVA build thread is all i have ever found also and was sufficient
- run,cut and glue *boom* control rod tubes/housing first before mounting boom to pod. Make sure rod tubes are glued inside boom only to last 1.5" of boom that slips over pod (fat end) otherwise rods will interfere with gluing to pod. Rods have to lift slightly and slip over inside lip of fuse pod = reason.
- There is no law banning running boom control rods outside boom ! Considering how much time and trial+error it takes to get it right running them inside the boom i will probably just run them outside and make two tiny holes in pod next time i build one of these. What a pain in the a$$ it is to run them inside = no more
- make sure when you glue boom to pod, have main wing panel mounted level to table surface and then align boom+elevator+rudder to wing panel with slow set epoxy. slow set allow mini adjustments.
- I created another spoiler servo mounting bay ( a second one with 3/32" balsa) next to existing one to allow excess servo wire to flop around the first bay. No trying to crowd it all into one bay.
- an servo arm with extension screwed into servo arm was used to simply push the spoiler up at 45~60 degree angle. No mechanism used - 100% works fine. two 15$ Servo trays will simplify the process.
- spoilers when deployed at 45 degree angle will drop the model with great authority - more angle would mean more severe decent.
- As best i remember about 1 oz was needed in nose to balance CG
- For flat glide the Elevators TE is level with adjacent horizontal Rudder rib outline
- Never used ballast tube but your location my need it.

This model has three great things going for it - relatively light weight allows this model to stay up longer than moldie in marginal thermal conditions, no need to worry about blowing up wings on winch although i launch it like a strong woody pulsing the pedal, the thin airfoil allows you to scoot and cover a lot of ground searching for or getting to thermals

My 3.6 and 4.0 Eagle res's are my 'go-to' contest models. Aside from my Oly2 woody these two models helped my get from LSF 1 to LSF3 in 2015.

Welcome back to gliders, this is a great choice you made

john s.

ps - For LSF4 & 5 TD tasks my current project is Sailaire!, wings, elevator, rudder done!!!






Last edited by jswain; Dec 24, 2015 at 11:45 AM.
Dec 26, 2015, 06:50 AM
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Thanks for the links to the other posts with information on the Eagle. Of course, I had read them carefully and have considered the issues you mention. Stay tuned to see how I solved them. Just one man's solutions. Thanks for the welcome back to gliders, but it's a bit late, I flew ALES at the NATS the last two years and have been actively flying gliders since around 1995.
Dec 26, 2015, 08:06 AM
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tail considerations


The kit comes with the vertical fin pinned in place with a snug carbon rod. This allows removal of the fin for travel or fitting in a smaller bag. The pin and fin could be easily glued in place permanently, but I like the option to remove it. I'm not happy to have parts that I take off and on not easily replaceable, plus the carbon pin is pretty snug, as it should be. I opted to put a small dowel plug about 1/2" long in the end of the boom and drill the dowel for a #4 short self tapping screw. Weight gain is negligible.

The kit also comes with a rudder control horn that can be slotted into the balsa block in the rudder. I put that in place but wasn't happy with the geometry or the possibility of the horn pulling out during extreme g force landings. I opted to use a bolt-on horn a bit above the exit area of the pushrod giving a slight downward force as a keeper. Since I'll be removing the fin every flying session, I wanted this to be simple.
Dec 26, 2015, 08:26 AM
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pushrods


I used a method from Rob's fine post for attaching the bent wire link to the rudder. A piece of brass tube was soldered to the wire, the CF pushrod epoxied in using JB Weld. JB Weld is very strong epoxy, but a slow cure, 4-6 hours. Since the model's well being depends on these pushrod joints, I'll happily wait. I then place a piece of heat shrink on the joint, and wick some thin CA in. Me thinks if this joint fails some very bad things have happened.

I used the MP Jet clevis for the elevator and will for the servo links. They are strong, and no slop on the threaded link, pins are brass not plastic. They have served me well on many other models. The brass pin fits the elevator's predrilled hole perfectly. I drilled out the rudder horn very carefully insuring a snug fit with no slop to the bent wire link. I use a pin vise with an assortment of drill bits to be sure the fit is tight.

The included CF pushrods are hollow and I have heard of problems with them. I've broken a hollow CF rod in the past myself on another RES that was stopping a bit fast. I may change these out for hollow stainless rod, but using them for the moment.
Dec 26, 2015, 09:40 AM
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Boom slots for pushrods


Tape the boom where cuts are anticipated. Lay out the pushrods along the path they will travel and mark the tape. I cut the slots with a Dremel cutoff wheel very carefully. The picture shows the placement of my cuts, YMMV. I used a round chain saw sharpening file to angle the slots to better match the pushrod sleeve path. It fits perfectly in the slot.
Dec 26, 2015, 09:54 AM
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Gluing the pushrods to the boom


As per Rob and others, I used the magnet method to place the sleeves. I scuffed the pushrod sleeves with sandpaper and also scuffed the inside of the boom. Then cleaned both with alcohol.

I had some small rare earth magnets on hand. They pull much harder than standard ferrite magnets. With a music wire rod in the pushrod sleeve the pull of the magnets was very evident and helped to place the magnets to reduce friction. An easier task than I anticipated. I ran CA down the rods protecting the area where the pod will later attach. Gravity and a flashlight to observe made this pretty simple.
Last edited by Barry Andersen; Dec 26, 2015 at 10:08 AM.
Dec 26, 2015, 01:12 PM
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Tow Hook cut out


I have somewhat different information about the placement. I went with SUSA and Ed Stewart. Both recommended a start CG of 89-90. So I placed the back edge of the tow hook a bit rearward of that. I'll report back after flying enough to find the CG and tow hook happy spot. It's set forward now to avoid forgetting about it during first flights. I prefer having a direct way to measure the hook placement. I came up with 20 inches from the nose to the front of the hook opening, YMMV.

Note: after some flying I have the back of the hook 20.75 inches from the nose. Install the hook based on that information; perhaps 20.25 distance to the front opening of the hook slot??

Cutting the slot through a Kevlar fuse is a bit tough. The Kevlar wants to fuzz, a bit of CA helps that, but it's easy to have the Kevlar fuzz stick to the inside of the fuse, so it will need to get ground out.

Test fit the adjustable hook from the outside, then add some epoxy and drop into place with a pencil tip

After the tow hook is firmly in place it's time to join pod and boom. Put the wing and tail on, use your best eyeballing methods and slow set epoxy. I sanded the seams off the pod but still had a very tight fit.
Last edited by Barry Andersen; Jun 27, 2016 at 09:07 AM. Reason: new information
Dec 26, 2015, 01:30 PM
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Servo Tray and servos


I've read many reports about how good the MKS 6100 servos are. Alex at SUSA convinced me to give them a try. I have to agree, tighter than any other servo I've used. They seem great for this installation. Small enough to sit side by side as well.

Ed Stewart was kind enough to send pictures of servo installations and a ballast tube fastening alternative. My tray is 4.5" long cut down from the factory ply that comes with the kit. I added a section of 1/4" ply underneath at the back for the ballast support. I left some distance between the ballast bar end the the servos to insure that I could get the bar in and out easily. But oops, the side by side won't quite work. Fuse curve hits the servo arm. Going to have to change to the angled install that Ed shows.
Last edited by Barry Andersen; Dec 28, 2015 at 10:24 AM.
Dec 26, 2015, 11:56 PM
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Thanks for the build thread. I am considering buying one and your build is very informative.

Does the kit come complete (less servos, radio, battery of course) or are there other parts you need to purchase such as a wiring harness?
Dec 27, 2015, 04:19 AM
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jswain's Avatar

Not much needed...


Quote:
Originally Posted by Aerotopia


Thanks for the build thread. I am considering buying one and your build is very informative.

Does the kit come complete (less servos, radio, battery of course) or are there other parts you need to purchase such as a wiring harness?
One Plain-Jane "Y" harness servo extension for inside center panel connecting two spoiler servos and then servo extension from end of center panel 'Y' harness to receiver. I have one of those inexpensive LED battery status level inside fuse also.

js
Dec 27, 2015, 12:31 PM
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Quote:
Originally Posted by Aerotopia


Thanks for the build thread. I am considering buying one and your build is very informative.

Does the kit come complete (less servos, radio, battery of course) or are there other parts you need to purchase such as a wiring harness?
The kit is complete other than servo mounts and wiring for the servos. Those are personal preference items. You could glue or tape the servos in place, but I think servo mounts are $ well spent. Some will shorten the spoiler servo wires. For me it's more work than it's worth. I wrap up and tape in place.

You could use simple extensions for the servos. You will still need to disassemble one end of the extension to fish the wires out to the servo. I like having a fixed mount to plug into, but it's not a big deal. The Eagle has a nice little box to mount a connector to, I'll show it again. Ed Stewart used a different connector. The skills for soldering and making connectors aren't difficult. Again, I refer you to the Naton F3X series for great instruction on that.

You could get a custom harness built for you. Here's a link:
https://www.rcgroups.com/forums/show....php?t=2561231
I've not used him, but he's been making connectors for a long time. Also harnesses can be found online, do a search.
If you order a custom harness these dimensions will help:
10 and 3/4" from the center of the connector bay at the wing root to the first rib in the servo bay. If you buy extensions, 15" should do for the wing, and 17" from the connector/extension to the receiver. If you have the channels in your radio, having each spoiler on it's own channel allows some tweaking if there are slight variations in installation.

Geez, sorry, ask me what time it is and I've told you how to build a watch.... Hazard of my former teaching life.
Last edited by Barry Andersen; Dec 30, 2015 at 11:36 AM.
Dec 27, 2015, 12:38 PM
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Servo tray V2


So, I didn't figure the tray well the first time. There just isn't quite enough space to mount the servos side by side. I glued a 1/16 piece of ply to the top of the tray I screwed up and cut new openings. 4 and 3/4 long now. I routed out the new openings then cleaned up with a simple sanding stick.

The angled notch for the ballast bar is made with a Dremel drum, then followed up with a round sanding stick the correct diameter. A bit of eyeballing and guessing to get the angle correct.
Last edited by Barry Andersen; Dec 30, 2015 at 11:37 AM.


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