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        Build Log Sebart MythoS 125e ARF Build Thread...

#1 jfetter Aug 25, 2012 11:02 PM

Sebart MythoS 125e ARF Build Thread...
 
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I've been waiting for this one for some time, what a beautiful plane! I've been a Sebart addict for years now, this will be my 8th now and they just keep getting better. I've really wanted to get another 2M pattern plane ever since my C-ARF Impact went in @ SEFF 2011 but the prices seem to be getting higher all the time. This plane is close to 2M in size but the few extra inches Sebart has trimmed off, translates into a much cheaper option while still having the flying characteristics I want. The MythoS is a new entry for 2012/2013, built for electric and finished in a newer variation of his familiar color scheme, this one should really look great in the air. The T-Canilizer (or whatever they are calling this mini wing) is something I am not sold on but it looks darn sexy the way they've faired it into the fuse. Will it matter, for me likely no but I am willing to wait and see.

To start with, here are the spec's, most of the components weighed right out of the box, some of the electronics spec'ed from the vendors web site;

From Measured Weights
---------------------
Fuse 32.3 oz.
Cowl 4.4 oz.
Canopy 5.0 oz.
T. Canalizer 2.6 oz.
R Wing 13.4 oz.
L Wing 13.3 oz.
R Stab 3.8 oz.
L Stab 3.7 oz.
Rudder 1.9 oz.
Gear 4.4 oz.
Pants 1.8 oz.
W Tube 2.5 oz.
S Tube 0.2 oz.
Spinner 2.2 oz.
Hardware 5.1 oz.

Total (plane) 96.6 oz. (6.038 lb.) (2,739g)

From Manufacturer Specs.
------------------------
Hacker A60-5XS 17.0 oz.
Hacker X-110A 3.0 oz.
Servos (5) 8.75 oz.
Extensions 2 oz.
6S 5000 LiPo 28 oz.
AR 9020 RX 0.75 oz.
APC 18" x 8"E 3.0 oz.

Grand Total 159.1 oz. (9.945 lb.) (4,510g)

I plan on using the power system as Sebart has spec'ed out on the box, I've found his planes to fly pretty well as configured by him and I'm really curious to see how this new Hacker A60-5XS runs on 6S with an 18" prop. I was tempted as maybe others will be, to do an 8S setup but I've already got a few 6S packs and it's nice to be able to use them in more than one plane. Move voltage, less amperage or vice-versa, in the end it's all about watts (though more voltage clearly has advantages). In the end I am as curious as anyone to see how well it fly's on 6S, it seems large (almost 10 lbs AUW) for 6S but I'm willing to try. Here are some pictures out-of-the box, enjoy...

Jack

#2 jfetter Aug 25, 2012 11:07 PM

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As I do with all my planes, I took a heat gun to it first thing. Nothing major, like most Sebart planes the covering is top notch, the Oracover needed only a little tweaking but the fit and finish overall is perfect! The manual is straight forward as always, pictures are used to illustrate assembly and this plane really goes together easily. Like the other Sebart planes I've owned, assembly is fairly easy, gluing hinges and installing components with maybe 8 to 10 hours total build time. A build thread seems a little silly given the ease of assembly but IMO it's all about the pictures and getting good views of the parts, for me anyway, this helps get a good feel before I purchase.

I started with the stabs and rudder, gluing the pin hinges with 15-minute epoxy after dropping a nice blob of oil on the center pin to help keep the epoxy from getting into the hinge joint. The pre-drilled holes were perfectly fit, just a little epoxy worked into the hole first is all it takes. The phenolic horns glue in with medium CA and fit easily into pre-milled slots. The rudder comes with both a rear-servo or mid-servo pull-pull configuration available. I opted for the rear-mounted servo with the included 6" heavy duty hardware as pull-pull (IMO) isn't something I would notice. I personally think the stiffer, shorter linkage is preferable and with the battery being something that can easily be move forward or aft for proper CG, excess tail weight is not an issue.

The pins themselves are perfectly suited, no slop, well built and nothing you need to change out. Unlike many ARF's on the market, the Sebart hardware is NOT throwaway hardware and of decent quality. I have a large bag of Robart hinges laying around, they are not necessary, the hardware, all of it (so far) has been great. In the past I've been slightly annoyed with Sebart getting the servo cutouts a little too small, seems like this should be easy and in this ARF, they fit perfectly in the pre-cut openings. I opted for 2 x Hitec S-5245MG servos in the stabs and 3 x Spektrum 6020 standard servos for the rudder and ailerons. I had considered JR 3421's on the stabs and 8411's on the rudder and ailerons but at half the price, the Hitec/Spektrum option seems more than adequate and much more attractive.

I plan on using a Spektrum DSMx RX and a Castle 20A voltage regulator (with a 2000 mAh LiPo) to round out the radio gear. I have a couple 6S Thunder Power 65C 5000 mAh flight packs which are exactly what Sebart calls for so that leaves the motor and ESC left to purchase. I am sticking with the Hacker A60-5XS and considering the Hacker X-110A ESC (per Sebart Spec's) along with a Jeti Spin 99 which I already have. I am leaning toward the Jeti as the Hacker is limited to 6S, not great if I decide to go 8S later as I would then have to change out the ESC as well as the motor. I'll decide when I get to the motor, nothing urgent as I don't plan on finishing (with work really kicking my butt lately) for a solid week, the plan is to maiden the second week of September if all goes to plan...

Jack

#3 jfetter Aug 25, 2012 11:12 PM

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Here's some photos showing more of the plane, air cutouts and servo linkage and stab mounting, I haven't drilled the holes into the stab tube yet, right now they are held on by the flange bolt only. I don't plan in removing the stabs but it's nice to have that option, I will keep the plane in my trailer more than likely but this configuration is used on his other larger planes and it works well. The stab tube itself is CF with what looks like dense foam inside, the fit into the fuse was very tight and the stab pockets also a good fit. This seems a better system than Sebart's previous Wind 110 which most people ended up gluing the stab tube in place to solve what seemed like a little loose fit, this is not an issue with the MythoS. The rudder is certainly beefy, it flares out as many of his F3A planes, the idea being better tracking (or so I'm told) but it's a neat looking rudder and gets a lot of questions at the field (I have been flying Sebart's WindS 50e lately, which also has a flared rudder). I plan on getting to the wings tomorrow, they look quite easy with 4 pin hinges per aileron to epoxy and a standard servo to drop-in, should make for quick work. I am looking forward to the landing gear as well, which I haven't unwrapped yet, they appear to be a painted epoxy finish versus metal, a good look...

Jack

#4 jfetter Aug 25, 2012 11:16 PM

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More pics...

Jack

#5 jfetter Aug 25, 2012 11:52 PM

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For those familiar with Sebart construction, the plastic cowl has been replaced by a solid, well built glass cowl on this plane with very crafty hooks to attach it to the fuse (and two screws to then hold it in-place). Seems Sebart put a lot of thought into this plane as the cowl fit and finish with the fuse is excellent and so easy to do, it makes for an easily removable cowl for work on the motor or ESC. It's a real neat system where the T-Canalyzer, cowl and canopy all interlock yet look perfectly fit, very well thought through and engineered!

Jack

#6 HaventFlownSince2014 Aug 26, 2012 01:22 AM

very well documented Jack, thanks!

I am looking forward to following your maiden and hearing the flight reviews!

#7 jfetter Aug 26, 2012 05:41 PM

9 Attachment(s)
I started on the landing gear today, the gear legs are smooth, painted glass that match the color of the lower body of the plane, they look quite nice. The wheel pants are already cut, with notches for the axle and are molded to fit against the gear legs, this is a nice feature compared to older models where a fair amount of messing about was required to get them cut to fit and mounted. These are simple bolt-ons, nothing complex and mount to the plane with 4 x cap head bolts, with blind nuts already installed in the fuse...

Jack

#8 jfetter Aug 26, 2012 05:46 PM

6 Attachment(s)
The wings were easy to finish, with only 4 hinge pins to glue for each aileron and the servos to mount. A full-size servo drops right in the factory cutout and the hardware is good quality again, the same as with the elevators and rudder. I've found the best way to glue the hinges without getting any glue on the joint is to oil the pin first and work epoxy into the pre-drilled holes with a thin wire, twirling it and wiping it on the way out to get the epoxy off the wire. You don't need much and this method works much better than putting the epoxy on the pin as no matter how careful you are, some always seems to get on the hinge joint. The servo leads were long enough to just poke out by an inch and a half, so no servo extensions on the ailerons. I've included some shots of the wing mounting and wing tube, it's CF and fits in the wing sockets perfectly...

Jack

#9 jfetter Aug 26, 2012 05:52 PM

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I've now done everything I can until the motor shows up, should be later this week and from what I can see, it's a simple bolt-on operation. The ESC will mount right behind the firewall (they provide a mounting position under the motor as well) and there is tons of room in the fuse for batteries, in fact any combination of packs could be used in this plane with no real limit to size. I'm still thinking about using one of the Mejzlik CF props I've got laying around from an old plane versus and APC, I know it takes more to turn the thicker Mejzlik so I guess I'll wait and see what the amp draw is on the bench before deciding. Here are some beauty shots of the assembled plane, it will sit this way until the rest of the electronics arrive...

Jack

#10 pbusa1400 Aug 26, 2012 06:11 PM

Wow!!!!!! Where have you been hiding this bad boy, subscribed. Let me know when the maiden is.

Pablo

#11 pdawg Aug 26, 2012 06:12 PM

Jack,
Dang! That's a nice ARF! Is this a larger version of the other Sebart pattern plane you flew earlier this week? The quality is very impressive!

#12 rcjet lynch Aug 26, 2012 06:20 PM

Jack it looks great. I know the other Sebart planes you have done fly flawless, so I can not wait to get my hands on this one.

#13 kingsflyer Aug 26, 2012 10:32 PM

Gotta love those Sebart Yellow airplanes! Those swept and curved leading edges on the wing and stab are very impressive. If it's anything like my WindS50, the MythoS 125e is going to fly even better than it looks -- and it looks MARVELOUS!!

McD

#14 jfetter Aug 26, 2012 10:42 PM

Quote:

Originally Posted by kingsflyer (Post 22558820)
Gotta love those Sebart Yellow airplanes! Those swept and curved leading edges on the wing and stab are very impressive. If it's anything like my WindS50, the MythoS 125e is going to fly even better than it looks -- and it looks MARVELOUS!!

McD

Yellow/Black is the only scheme I want now, though I still have an AngelS 30e in white/blue. I love the way the WindS 50e fly's, I am in love with that plane and hoping this one fly's as well or better (I really want the bigger size too). You are right about the curved leading edges, very sexy and it really adds to the overall curvy look when assembled...

Jack

#15 bossee Aug 27, 2012 09:14 AM

Hi,
Almost all I have spoken to about Sebart planes say thay are one of the best ARF's regarding quailty. They fly very good also. I have two Sebart planes myself, one smaller Angel S 30E and one larger Wind S 50E. Hard to be disapointed with any of them. The Mythos 125E looks to be very good and I would be surprised if it does not fly very good also. Hard to justify the pricegap up to the 2 x 2M Mythos that is also available soon unless one compete in F3A. Mythos 125E seems to be enough seize to be able to cope with more windy conditions that the slightly smaller planes like Wind S 50E can not handle so well (but OK).

If it will be able to fly with enough performance on 6 cell LiPo it will be a "hit" I think (lower cost). But I suspect 8 cell is more optimal for it.

/Bo


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