My attempt at a SebArt Mytho S 50E

[Adrian Smith 1]

Having flicked through some back number RCM&E mags my eyes were drawn to January 2015's revue of SebArt's inimitable Mytho S 50E. Well that looks simple enough so lets see if it is. I decided to go with the recommended power train being the Hacker AS50-16S and Master Basic 70A SBEC & 16x12E prop. Lipo batteries is another story which I will relate later.

Anyway the box duly arrived nicely packed.

Because I couldn't find the JR servos recommended I am using Hitec 5245 mini servos on the elevators, and Hitec low profile jobs on the ailerons and rudder. I admit I cribbed that idea from a rival USA forum build thread.

Edited By Adrian Smith 1 on 12/10/2016 19:49:58

[Adrian Smith 1]

First job was to fit the main wing fences. Crikey! What a pain in the butt that was! The slots which they fitted into were covered by the film covering and do you think I could find 'em? There is no measurement guides in the manual. So after groping around in the dark I managed to find some slots and hoped for the best. Medium cyano is used here. The second wing was easier now I knew where to look.

[Adrian Smith 1]

Next I sorted out the aileron servos. The servo openings had to enlarged by a good 1.5mm all round to get then to fit. The horns were glued in using Gorilla glue. A departure from the manual as it was recommended to use cyano.

From then it was easy to fit the rods. However, there is a subtle difference in length compared to the elevator rods with no guidance as which to use in the manual. So I chose the shorter two rods for the ailerons which seemed ok.

Next step is the elevators which I will try and do tomorrow.

[Rich too]

sub'd

Why use the Gorilla glue Adrian? I love the stuff but the expanding nature does not suit all applications.

[Colin Carpenter]

Adrian - you will love this model's flying characteristics. Just watch the the rudder. That canaliser is powerful ! Colin

[ben goodfellow 1]

how do you find the 5245s ? i avoided using them in an EF exp because of the reported centering issues that some have had...having said that ive alot of hitec servos and had little in the way of problems .

[Adrian Smith 1]

Rich, I used Gorilla glue, albeit a very thin layer of it, as I wasn't convinced the slot was tight enough where the horn goes in for Cyano to do the job properly.

Thanks Colin I will take note.

Ben I have not tried the 5245s yet as I am going to do the elevators today hopefully. I had read about centring issues on a USA forum, but I have used Hitec on models of this size before so hopefully they will be okay.

[john stones 1 - Moderator]

Another very nice model Adrian, you spoil yourself the props these lecky motors turn is stunning

[Adrian Smith 1]

Yeah John, I know what you mean. At least it means I don't have money for the pub.

Okay so horns glued to the elevators with Gorilla glue after cyanoing the felt hinges in place. Next cut the horn slots which is a simply enough job.

[Adrian Smith 1]

Now comes the fiddly bit. The servos are slightly too big for the slots so 2mm had to come off two sides using a sharp blade and file. The servo wire was pulled through using a pair on long nosed pliers. Took longer than I thought in total though.

Hopefully, the servo arms will be long enough as this seems to have been a problem reading other forums.

Edited By Adrian Smith 1 on 13/10/2016 16:40:41

[Adrian Smith 1]

Next, I decided to use the pull\pull option for the rudder so I added the included horns and installed the hinges in the one surface. Next I cyanoed the tail wheel frame into the rudder. So all ready to attach it to the fuz tomorrow hopefully.

[john stones 1 - Moderator]

Did your servos not come with the extra long black arms in the box ?

Edited By john stones 1 on 13/10/2016 16:44:47

[Adrian Smith 1]

John, they had a longish blue metal arm which I will try. The rest were the typical small white kit that comes with mini servos. Failing that I will raid my spares box.

[Josip Vrandecic -Mes]

Hi Adrian , high quality , precision made ARF model with hacker 50..... is a good choice. As I turned 69 and I absolutely understand your approach when you once said :

''I did do alot of "proper building" early on to gain my spurs but I really like to fly not hence moving over it almost exclusively ARTFs.''

Many successful flights ,

Jos

[Adrian Smith 1]

I connected up the elevator push rods and horns. Not sure if they are long enough until i am able to connect up the Rx to centre them and see what the throw effect is (30%) by the way for initial flights).

[Adrian Smith 1]

Next I fitted the rudder using thin cyano as directed. Also a good tip based on the manual photo was to put some thin heat shrink tubing on the tail wheel bend to stop the wheel trying to move up the L-bend. No text in the manual so a good bit of studying was required on this idea.

[Adrian Smith 1]

All fittings in place for the pull/pull rudder arrangement. This is because (and it may be an expensive mistake on my part) is the RCME review used a light Lipo (3800Mah 6S) in the build although tellingly there was no comment on duration by Nigel Hawes. Most recommendations seem to use 4500 or 5000 Mah lipos.

Next I fitted the rudder servo. By the way the low profile Hitec one did not fit. Grrrrrrrr! so I used a spare Hitec 645 MG standard servo. The servo arm will have to go as it's too short. the gap between the rudder horns is 50 mm so I need to fit a servo arm of similar width the retain that "box shape".

More next week.

 

Edited By Adrian Smith 1 on 14/10/2016 17:59:28

[Rich too]

Good stuff Adrian. Do you not have a servo tester?

[john stones 1 - Moderator]

Heavy duty Hitec one is 65mm to outer hole centers

Edited By john stones 1 on 14/10/2016 19:05:31

Edited By john stones 1 on 14/10/2016 19:06:19

[Adrian Smith 1]

Thanks Rich. I do have a servo tester somewhere in the drawer! I will put it to good use when I finally get round to setting up the radio. I just need to get past the gluing stage.

You are right John. However, I found a slightly shorter Hitec servo double arm in my spares box which is about 55mm so I fitted that. More photos of that when I fit the pull/pull wires next week.

The U/C legs were bolted as per the manual although I did use thread locker on all 6 bolts as part of my belt and braces approach.

[Adrian Smith 1]

While think of it the guy, George I think but may be wrong, at 4-Max has been exceedingly helpful to an electric ignoramus like me. Helped no end with my questions. 4-Max and the Component shop also have sent stuff like connectors etc very quickly so great service all round.

[Adrian Smith 1]

After a bit of flying Monday it was back to the workshop. I freely admit I am not following the sequence of the manual , but it works for me. Next I threaded the rudder wires and attached then to the servo and rudder horns, all to be adjusted finally later.

I must say the kit is not over generous with the length of wire, but they were just about ok.

[Adrian Smith 1]

I thought I would add the canaliser which I must say lined up correctly and level/aligned with the main wing. Medium cyano is recommended here.

[Adrian Smith 1]

Last job for the day was to fit the stabilisers and thread the servo wires through the fuz. That was fun believe me. the manual recommends servo leads of 900mm which I had to make and crimp both ends.

The servo wires are taped to the fuz until I eventually fit the RX when I decide where it's going.

[Adrian Smith 1]

Next on to cutting out the airflow cooling triangular holes under the firewall. This was straightforward because access was simple.

However, the rear exit holes was another matter. Whilst the cutting shape imprint was visible from the inside of the fuz, to get a knife to them was not possible because the former position made it impossible. The way was from underneath and once again was like playing "Blind Man's Buff". Another job that was a irritation.

Edited By Adrian Smith 1 on 20/10/2016 19:41:06