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Old Feb 23, 2012, 12:39 AM
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The wiring for the lights was a bit short, so several extensions had to be made, and soldered.

In the end all wires were pulled through no problem.

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Old Feb 23, 2012, 12:43 AM
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For the strobe I will use one of these high voltage ones (300V). The twin has some really large capacitors

I will probably just use the single strobe.

http://www.hobbyking.com/hobbyking/s...dProduct=11745

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Old Feb 23, 2012, 12:45 AM
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The mains retract mount area is ok but not the strongest (as in the CMP T-45 / Hawk).

I used some epoxy and carbon cloth to close various gaps make it a bit more solid.

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Old Feb 23, 2012, 05:23 PM
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The flap linkages are nicely made ... no problem installing them.

I used generous amounts of epoxy mixed with microbaloons to make sure the hinges stay in place. The flap horn fell apart and had to be re-glued together.

It looks like a cool setup. I just hope one of the two flaps won't fly off in flight

I needed to cut down a hex key to get it to work in there. I used twin HS-81 MG I already had lying around. They are good, strong reliable servos, and fit perfectly.

It is a good thing that the flap linkages can be properly adjusted. Later everything will be set permanently in place with dabs of epoxy.

Flap operation video :

CMP L-39 Flaps (0 min 17 sec)


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Old Feb 23, 2012, 06:42 PM
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The L-39 wing is basically done.

I used 2-56 clevises for the ailerons. The ones that come with the kit are similar to the Hawk one and rather flimsy.

The retracts fit right in, all I had to do is drill four guide holes.

There's a lot of wires now coming out of that wing

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Old Feb 23, 2012, 11:01 PM
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Quote:
Originally Posted by Herb View Post
The L-39 wing is basically done.

I used 2-56 clevises for the ailerons. The ones that come with the kit are similar to the Hawk one and rather flimsy.

The retracts fit right in, all I had to do is drill four guide holes.

There's a lot of wires now coming out of that wing

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Thanks Herb, i will be working on the L-39 next.
what EDF setup are you going to use?
I have a CS 90mm EDF but no motor yet.
any input will be good.
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Old Feb 24, 2012, 02:55 PM
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Hi there,

I will be using the WeMoTec Midifan 90mm on this one. Most likely an 8S setup that is dimensioned so that it can do 9S as well

I have the CS-12bl fan but it looks a bit too heavy for me, and at this point I lean towards better efficiency.

Roughly 80% of the sound effect has nothing to do with the fan, but with the way it is mounted.
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Old Feb 24, 2012, 03:00 PM
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The fiberglass horns have to be mounted properly, with the clevis hole right above the hinge line (pivot), at 90 degrees with respect to the moving surface.

Otherwise the servo just tries to push the moving surface out of it's hinges, instead of applying torque to rotate it.

In the case of the elevators that means that the clevis and stud have to be very short, unless of course one relocates the servo.

Which implies one can't use the same setup as for the ailerons, where the distance between the servo and the hinge line is larger ...

The slow cure epoxy (hysol) allows plenty of time to adjust things properly.

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Old Feb 24, 2012, 03:09 PM
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... the reason for the flimsy thin linkages that come with the L-39 kit is clear:

They recognized that the servos that will fit in the surfaces will be by necessity rather small and thin. As a result, the servo horns won't be able to take any sort of
thick metal clevis.

So one has two choices

(1) either one keeps the stock linkages and makes then more rigid with carbon or aluminum tubes; or

(2) one enlarges all the servo arm holes, uses bigger horns (like the fiberglass ones I used), and then chooses standard 2-25 metal clevises & studs.
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Old Feb 24, 2012, 03:13 PM
chillax! It's only a Hobby
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looks great,i just finished a NP Mig 15 with the 10 blade CS fan,4100kv put out 900w at 60amp,and it sounds great! can't wait to Maiden it!!
I still might try the CS fan on the L-39,also got a CMP Hawk will be using the Stumax fan on that one, any input on the Stumax?
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Old Feb 24, 2012, 05:59 PM
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I think the Stumax is efficient but quite a bit heavier than what I am using. It will do best on larger models that need more power maybe?

( In the pictures below both fans use the same motor (SK3 EDF) at 249g ).

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Old Feb 25, 2012, 09:18 AM
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Hi Herb what motor are you using ?
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Old Feb 27, 2012, 12:26 PM
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.. not sure yet. I have a Neu 1515/1.5y (kv=1500) lying around unused

Other options - for me - would be motors in the 300-340g range suitable for the 90mm MidiFan (36mm can diameter) and with a kv in the 1500-1600 range.

That would then include Neu (1415 open endbells or 1515 with HET shroud), Arc, Leopard and similar (Tacon LPB 3674 open endbells or HK XK3674-B-xxxxkv open endbells), Mega, Tenshock, JePe EDF 8S setups, etc
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Old Feb 27, 2012, 01:27 PM
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Installed the nosegear, fits nicely.

The steering servo has to be all the way forward. Some dremel work here and
there to make the wheel and steering (tiller) arm fit.

Note the tensioner for the pull-pull steel wire steering.

To save weight and complexity, no gear door . I made a nosegear hatch out of sheet styrene, as the fg one included is not very useful.

I wanted to fit a larger MG steering servo, but nothing I had would fit ! A bit unhappy about using such as small servo on the steering ... we shall see.

The nosegear steering went the other way compared to the rudder. Either radio mixing on two channels, or a quality HK servo reverser.

Retract operation video :

CMP L-39 retracts (0 min 19 sec)


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Last edited by Herb; Mar 18, 2012 at 07:40 PM.
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Old Feb 27, 2012, 01:28 PM
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Tamiya acrylic XF-20 (medium gray) and XF-66 (light gray) are a very good match for the grey paint.

The blue is matched very closely by testors acryl "cobalt blue".

Will need that later for that hideous white canopy frame

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