Teakle ASW 20 3.5/1

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Peter Balcombe
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Location: Clevedon, North Somerset, U.K.

Re: Teakle ASW 20 3.5/1

Post by Peter Balcombe » 20 Apr 2017, 17:43

Martin,
My aileron servos are analogue TowerPro MG90 metal geared micro units which have been fine.
They have a quoted torque of 2.2Kg/cm at 4.8v, which is how I run mine.

Andrew,
It is a long time since I built my '20' but I am pretty sure I built the tailplane as normal with the 1/4" balsa LE & elevator spar as per the plan .
I think I just dug out the enough foam to sit the JR NES xxx servo in place on the inside of the upper skin, packed it to be firmly sandwiched between the skin veneers and epoxied some small full foam depth balsa blocks around the servo lugs to make sure it didn't move around. I then glassed the completed tailplane and elevator prior to painting. I am pretty sure the servo fitted behind the diamond shaped balsa block, with the horn/Clevis on the centreline so that it sits in a slot at the rear of the fin top ply plate.

Andrew Wallace
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Re: Teakle ASW 20 3.5/1

Post by Andrew Wallace » 03 Jun 2017, 19:27

Looking a bit more help
Any pictures or measurements for were the servo boxes go for the flaps, airbrakes and Servos
Thanks

Andrew

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Peter Balcombe
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Re: Teakle ASW 20 3.5/1

Post by Peter Balcombe » 03 Jun 2017, 20:29

Andrew,
I don't think that there any definitive locations for the airbrake & flap servos (although the original PT kit building sketches probably show the approximate airbrake location and assume the flaps to be operated via a fuselage torque tube & single fuselage mounted standard size servo arrangement)

I mounted my airbrake servos (micro servo size) on 1/16" ply plates epoxied into balsa lined rectangular cutouts made in the underside of each wing so that the servos were completely hidden beneath the lower wing surface. There may be a length of Bowden cable tube pre-installed into wings, with end points marked on the lower wing surface, but I can't remember now. If so, then install brakes at outboard end (with sufficient space to get full brake attachment movement without fouling the tube) & mount the servo box sufficiently far inboard of inner end of tube to allow room for servo attachment and full movement. Position the servo box cutouts so that the airbrake actuation cable quick link will be in line with the servo arm for a straight push/pull action. The servo box can be fitted with a removeable flush fitting lid. Either secure the lid using small countersunk head screws (see Model Fixings website for a range of these), or use tape.

For the flaps, I bottom hinged my flaps and used Hitec HS-225MG mini sized servos located approx 1/3 of the way along the flap (as near to centre as I could get it whilst still having sufficient wing thickness to accept the servo body within a lined servo box cutout). The servo itself was securely mounted on a lower wing surface flush ply plate, which itself was firmly screwed to the servobox frame. The servo arm poked through a slot in the ply plate which permitted full servo throw movement. The 1/16" thick epoxy sheet flap horn was epoxied into the lower surface of the flap to give nearly 90 degrees down flap & zero up flap.
Note that you can mount the servo towards the rear of the wing to minimise linkage length, but remember to leave enough for mechanical adjusters to enable the servo travels/servo horn angles to be setup the same on both wings - otherwise the flap movements will be different.
Note that as the flaps are more likely to touch the ground/grass during a landing if flaps not retracted immediately before this point, significant shock loads can be transmitted back to the servo gears/servo attachments - in addition to flap drag loads - so the servos/installation needs to be able to withstand this without being torn from the wing!

I am away from home at present, but will try to remember to take some photos of my ASW20 installation when I get home in a couple of days.
Hope this helps,
Peter

Andrew Wallace
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Re: Teakle ASW 20 3.5/1

Post by Andrew Wallace » 04 Jun 2017, 07:01

Thanks Peter :D

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Peter Balcombe
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Re: Teakle ASW 20 3.5/1

Post by Peter Balcombe » 06 Jun 2017, 09:54

Andrew,
Having just got home & looked at the original build instructions and one of the wings, I can see that my previous post was not quite right.
The original wings were supplied on the assumption that both flap & brake servos would be fuselage mounted.
Thus there was a brake Bowden cable tube pre-fitted to exit the wing root forward of the main spar.
I didn't mount the flap servo on it's cover after all. I note that the brake cable connection needs a bit of TLC :o
The attached photos should explain what I did & this works ok for me.
Attachments
ASW20 Flap_Brake servos small.jpg
Flap & Brake servo locations
ASW20 Brake servo closeup small.jpg
Brake servo closeup
ASW20 Flap servo closeup small.jpg
Flap servo closeup
ASW20 Flap servo small.jpg
Flap servo

Andrew Wallace
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Joined: 20 Mar 2015, 08:33

Re: Teakle ASW 20 3.5/1

Post by Andrew Wallace » 06 Jun 2017, 18:54

That's first class Peter
Thanks
Andrew

Martin Church
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Location: Somerset edge of Mendips

Re: Teakle ASW 20 3.5/1

Post by Martin Church » 28 Jun 2017, 15:10

Well after grilling Jeff & Chris at WS on Saturday I've ordered a Turnigy G60 motor & a YEP 80 esc
Surgery was performed on the nose of the 20 & soon it will be sporting an Aeronaut 16x10 folding prop.
It solves for me the question of where & how many Receiver packs I needed to get the CG where it should be with the bulk of that weight now being the motor & esc.
Pictures to follow after work. I've also trimmed my canopy frame down to a 6mm wide base. I just need to trim the fuselage rail around the canopy to suit.
Last edited by Martin Church on 28 Jun 2017, 15:15, edited 1 time in total.

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Cliff Evans
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Re: Teakle ASW 20 3.5/1

Post by Cliff Evans » 28 Jun 2017, 15:12

Not another Semi scale motor job!!!

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VinceC
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Re: Teakle ASW 20 3.5/1

Post by VinceC » 28 Jun 2017, 15:13

Well said Cliff. This is a scale site. Harassy

Martin Church
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Re: Teakle ASW 20 3.5/1

Post by Martin Church » 28 Jun 2017, 15:16

Oh dear I've upset the purists :roll:

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