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Electric Ducted Fan Jets Discuss electric ducted fan jets here including setup tips, power systems, flying techniques, etc.

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Old 11-17-2011, 11:12 AM   #1
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Default Skyangel / J Power Mini 50mm EDF's

Seems other thread has died and no interest ?

I'm still looking for all information from other owners of these EDF's ...

Questions today with particular reference to the T-45 hawk :

a) It seems the under cockpit area is set-up as, working back from front to rear .... :

In nose is the LiPo, then behind that the Rx, then the elevator servo.

In my mind this creates a CoG problem as the LiPo is so far fwd giving a nose heavy situation.

How are others setting up in there ?

b) ESC to battery lead was very short and I had to lengthen with short additions to clear the elevator servo arm.

Anybody else have that problem ?

c) Nose wheel position is near scale place ... but again far fwd and will affect CoG seriously .... especially if you have a servo to steer it ...

Anybody set the nose wheel further back ?

C'mon guys ..... Please HELP !!

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Old 11-17-2011, 10:50 PM   #2
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Sorry, I can't help you with the T-45, but I have flown the F-18 and the Mig-15 (my new plane). The F-18 flies great with no cg issues.

I flew the Mig for the first time today in 15-25 mph winds. The plane seemed a bit tail heavy to me, but its hard to really tell flying a new plane in those winds. I was chasing it all over the place, but was able to maintain enough control to land it safely.

The battery compartment is REALLY tight! The Lipo is up front and the elev servo and receiver are side-by-side (see photo). She has plenty of power, but I need a calm day to figure out exactly how she needs to be tweaked.


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All of my landings are three point landings if you count the spinner, too
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Old 11-18-2011, 03:47 PM   #3
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I'm just surprised that the LiPo is so far fwd on the T-45 ... with servo tucked back at rear of slot.
I can slide my RX under the servo so that helps ... but still leaves LiPo right up in nose.

What I'd like to see is a photo of another T-45 set-up to compare ...

I enlarged the battery area and then fitted a 1/16th light balsa plate in to give back strength ...



Here with 1000mAh 3S 20C at 84gr ....



In model ...



Hung at CoG point via my "skyhook system" ... (old flybar from my heli bent and hooked to string from ceiling ... hole is made through fuselage and a plastic tube inserted through for wire to feed through .... )



Here with 1800mAh 3S 25C at 128gr ...



In Model ...



Hung at CoG point ...



The 1000mAh is only about 10gr's heavier than the spec'd 850mAh 3S ... so I'm surprised at the nose heaviness ....
To get to a slight nose heavy setting - needs 60gr at tail end with the 1800 LiPo ....

I've checked all weights and there is no way that the model can ever meet the stated weight in the advertisement of total Flying weight 330gr. Lowest I can get it to is 385gr. with advertised 800mAh LiPo weight allowed for.

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Old 11-20-2011, 08:00 PM   #4
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Today gave it maiden flight ... 1800mAh 3S 25C in the nose ... reduced tail weight to 30grams ....

Flew on rails ............ and fast. Very happy.

http://www.youtube.com/watch?v=wRbsHH3Cv68

Only downer was that the aileron rods being under wing - I stripped one servos plastic gears in landing second time.
This is not a simple matter to sort - as the wing is glued in place with servo lead going up into fuselage ... luckily the servos are exact same as the Skyartec Cessna's that I have just modified to separate aileron servos. That meant I have a fully working Skyartec servo in hand. I took the gears out of that ... fitted to T-45's servo and she's all fine again.

When I run out of gears - I shall replace with metal geared servos and that should sort that.

Verdict ? Magic !

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Old 11-20-2011, 08:27 PM   #5
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Very happy for you! You certainly put your homework in on this one!

All of my landings are three point landings if you count the spinner, too
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Old 11-20-2011, 10:09 PM   #6
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I'm certainly very happy with it and even though I pushed the limit with the size of LiPo ... I shall be getting more 1800's ... as they fit my Cessna as well ...

Judging by the glide on it when landing - she can take weight quite well ....

I have a set of wheels coming for her - based on the HK Stinger ... so that will make her a ROG interesting project ... I may even push up to 4S as others have done ....

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Old 11-20-2011, 10:35 PM   #7
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Its never enough, is it? LOL! In a weird way, its almost anti-climatic when a plane flies well. Time to move on to the next challenge!

All of my landings are three point landings if you count the spinner, too
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Old 11-21-2011, 01:11 AM   #8
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Originally Posted by solentlife View Post
Today gave it maiden flight ... 1800mAh 3S 25C in the nose ... reduced tail weight to 30grams ....

Flew on rails ............ and fast. Very happy.


Only downer was that the aileron rods being under wing - I stripped one servos plastic gears in landing second time.
This is not a simple matter to sort - as the wing is glued in place with servo lead going up into fuselage ... luckily the servos are exact same as the Skyartec Cessna's that I have just modified to separate aileron servos. That meant I have a fully working Skyartec servo in hand. I took the gears out of that ... fitted to T-45's servo and she's all fine again.

When I run out of gears - I shall replace with metal geared servos and that should sort that.

Verdict ? Magic !
Looked like you were having blast with that plane. I am thinking of buying a stinger and after watching that video I think I shall. Wont be as nice as your plane there but. I say Bloody Hell mate lets go fer it, I raise my pint to you sir, Congrats and thanks for sharing. Cheers

Happy flying may your crashes be limited and if they are not limited let them be cool.
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Old 11-21-2011, 01:34 AM   #9
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After watching your video, I know what my next airplane will be! That thing is a BEAST! It puts my Mig to shame!

So, when your battery finally dropped below the esc's limit, it didn't just shut down on you? I flew my Mig Friday evening until the stock 850 mah gave up. I was actually bringing it in for landing when the esc shut down completely. I had nothing. She did a 180 degree roll to the right and nosed in. I had no servo control, whatsoever. Maybe I need to reprogram the esc.

All of my landings are three point landings if you count the spinner, too
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Old 11-21-2011, 03:06 PM   #10
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Originally Posted by earthsciteach View Post
After watching your video, I know what my next airplane will be! That thing is a BEAST! It puts my Mig to shame!

So, when your battery finally dropped below the esc's limit, it didn't just shut down on you? I flew my Mig Friday evening until the stock 850 mah gave up. I was actually bringing it in for landing when the esc shut down completely. I had nothing. She did a 180 degree roll to the right and nosed in. I had no servo control, whatsoever. Maybe I need to reprogram the esc.
Usually you should be able to close throttle and open it again - give you another 10 - 20sec of power - but it takes the last bit out of the pack and can damage it.
My pack was showing zero on the wattmeter when I checked after that flight .. it charged up fine.

I've been trying to put the vid through doppler speed check - but not having much success ... we estimate she's hitting about 65-70mph - so we have a way to go yet ... I'm hoping to push her to over 80....
Note that I have done no work or mods on the fan / motor at all - they are running straight out of box.

I did lift EDF out last night to check to see if any binding / grooves from fan blades .... nothing. Clean as a whistle. Double side tape instead of hot glue to put it back in slot then bolted up secure.

Today made next modification to her (not for speed - this is just for my convenience to save hand-launching when on my own ... )

The EDF mini jet as supplied by Hobbyking is without the wheels that Skyangel supply ... yes it is better without and looks nice "wheels-up" in the air.
But I like ROG and wanted wheels option. So wanted lightweight wheels but with reasonable legs.
The Stinger 64mm EDF of Hobbyking has fixed wheels option that can be bought separate, about $6 which also includes a 9gr nosewheel servo ! Paypal made and they arrived today.

Main wheels are a touch large - but they can soon be changed down in size ... legs are good, mounts are such that legs can be removed easily for hand-launch "wheels-up"..... leaving just the nose pin and flat mounts in wing.

Here's whole lot on scales ... not too bad considering servo included as well ...



First main wing ... which has Skyangels slots already moulded in. These have to be enlarged a touch by use of soldering iron ...



Flat plate mounts epoxied into place ..



Front mount being offered up ...





Soldering iron needed to enlarge nose aperture ... but luckily the nose has a hollow inside that just allows the servo and box in. The battery is against a bulkhead that sits at back of nosewheel box - so that's clear OK. The servo lead is long enough to skirt battery and reach RX.

Main gear slotted into mounts ..



Fitted :







AUW without battery is 375gr ...

With 1800mAh 3S 25C = 504gr.

Sounds a lot compared to advertised AUW flight ready at 330gr - a figure that I find hard to believe.

Once I get my 1300 and 800mAh LiPo's for the model - that should void significant amount of the extra weight ... plus I still have option to remove UC to get back to hand-launch state.

Now I have to wait till I get back from work assignment to test.

I'm also thinking which 50mm EDF jet to get next ... the Mig 15 is high on my list as I live in Ex Soviet state ... either that or wait for any more models they may bring out ... Mirage 2000 would be nice ... or even better would be Panavia Tornado ... anyone from J Powers / Skyangel reading this ?

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Old 11-21-2011, 03:21 PM   #11
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Originally Posted by Fishbonez View Post
Looked like you were having blast with that plane. I am thinking of buying a stinger and after watching that video I think I shall. Wont be as nice as your plane there but. I say Bloody Hell mate lets go fer it, I raise my pint to you sir, Congrats and thanks for sharing. Cheers
Having a blast ? I felt like Santa had come !! The smile was so big my face hurt.

What surprised me was even though its a small model - it was actually easy to see in the air .. video guy had trouble at start as he didn't expect it to be so quick !! But once he got in the groove - I think he did a good job ... (video by old Sony 8mm CamCorder ... then fed to DVD recorder to create VOB file ... computer conversion to wmv or other format for youtube ... reason for using the old 8mm camcorder is the picture quality and also zoom capability ... much better than many digi-cam offerings ... )

Stinger was on my list ... but wanted something that actually represented something. Being a die-hard Brit ... I was looking for the Red Arrows BAe Hawk, but they were not available and I took the T-45 instead ... which is really the same aircraft - just renamed by US military.

I'm considering going the 4S option to crank up the RPM ... see if I can get her to go faster ... I'm sure given my style - the motor will soon burn out with 4S ... so I will then look to have a higher KV in there and stick with 4S ... really get her on song ... maybe approach that magic 100mph ?

I have a 2 week assignment to complete starting tmrw ... so I shall be itching to get home and back with this little baby.

There will be more vids as I experiment with this beauty .... so keep watching !

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Old 11-23-2011, 08:59 PM   #12
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Checked various parts of video with Doppler Speed program and results were 80 - 85km/hr on the straight level low passes and over 90km/hr in the shallow dives ...........

That's with stock motor / fan on a 3S pack .... so what will she do with a 4S ?

I've now fitted HK's Stinger landing gear which is removeable for hand launches and best flight set-up. All up ready to fly is now 504grams with gear fitted .... (total gear weight including nosewheel servo is 57grams).

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Old 11-24-2011, 12:34 AM   #13
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Hope she doesn't do this with a 4s!

http://www.youtube.com/watch?feature...&v=sJcqZQf3IVs

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Old 11-24-2011, 04:01 AM   #14
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Wow that is the most realistic RC Fire I have ever seen LOL
Actually that is almost sad what a way to land. However it had to looked cool coming in like that though

Happy flying may your crashes be limited and if they are not limited let them be cool.
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Old 12-04-2011, 10:49 AM   #15
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Seems plenty of people have upped to 4S LiPo's ... and one guy on Youtube fitted a 6000KV motor ... tried watching the vid - but model was so fast ..........

First mod I've done is to fit Hobbykings Stinger wheel set ....



There is one area of concern - the nose wheel is heavier than anticipated with the servo installed in the mount.



AUW of the model is now touching over 500gr ... so EDF power is going to be a major consideration next.

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Old 12-04-2011, 02:37 PM   #16
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Just checked back in on your thread. The landing gear mod you made is very nice! $6 for the set with a steerable nose wheel is a great price.

I'm still working the bugs out of my Mig. She just doesn't perform well. The roll rate is horrible and she is rather slow. I'm flying it on the stock motor/fan and 850 mah 3 cell.

All of my landings are three point landings if you count the spinner, too
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Old 12-04-2011, 07:29 PM   #17
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Originally Posted by earthsciteach View Post
Just checked back in on your thread. The landing gear mod you made is very nice! $6 for the set with a steerable nose wheel is a great price.

I'm still working the bugs out of my Mig. She just doesn't perform well. The roll rate is horrible and she is rather slow. I'm flying it on the stock motor/fan and 850 mah 3 cell.
The wheel size is a touch larger than I would really want on the mains ... the nose wheel is slightly smaller ....... so might change to smaller all over ... which may also reduce weight. At $6 incl. servo ... I couldn't resist.

I've watched and read other stuff on the Mig and I think maybe you've got a bad example. I think my T-45 - I was lucky to get a good example.

They are cheap EDF's and probably quality of build is not so consistent.

I actually fancy a Mig as next - to create a sort of combat twin set ! I know ... the real twin set is the Sabre / Mig .....

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Old 12-04-2011, 07:41 PM   #18
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I chose the Mig because my friend that I fly with at school is getting a Sabre. I am confident that it is simply a matter of learning curve on my part and working out some bugs on the Mig. I just got back in from flying my 800 mm Spitfire. I've spent months figuring it out and modifying it. It flies great now and I find that very satisfying.

I never viewed that Mig as an attractive airplane, but saw a Mig-17 perform at an airshow this summer. It was beautiful in the air and could fly circles around the L-39 Albatrosses that the remainder of the team flew. I guess I sort of fell in love with the Mig after that!

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Old 12-07-2011, 03:22 PM   #19
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Originally Posted by earthsciteach View Post
I chose the Mig because my friend that I fly with at school is getting a Sabre. I am confident that it is simply a matter of learning curve on my part and working out some bugs on the Mig. I just got back in from flying my 800 mm Spitfire. I've spent months figuring it out and modifying it. It flies great now and I find that very satisfying.

I never viewed that Mig as an attractive airplane, but saw a Mig-17 perform at an airshow this summer. It was beautiful in the air and could fly circles around the L-39 Albatrosses that the remainder of the team flew. I guess I sort of fell in love with the Mig after that!
I like both the 15 and the 17 .... and given the intakes - they should be good DF models. I had one back in 80's built from Radio Modeller plans in UK ... had a prop on a IC 20 engine up front. The amazing thing was that it would bank and steer on RUDDER without ailerons, even though it was a full 4ch machine. We put it down to the wing design..... plus the slight anhedral.

Right back to the nitty-gritty ..... have done some tests now that I'm back from I*** desert and home ...

Wattmeter comparison figures at WOT ....

1800mAh 25C 3S E-Fly pack I used in the video .... gave 210W with 18A

so I tried a recc'd 800mAh 20C 3S pack as you have in your Mig ? Its a Turnigy new pack as well ..... gave 170W with 16A ....

then I tried the pack I intend vto be my 3S usual pack to offset wheels weight - 1300mAh 3S 25C - this gave also 170W at 16A ... cycled it on the charger and FRESH of charger got 18A and 220W ... but thats with the pack straight from charger to model.

As an experimenmt and to prove apoint - I plugged in one of my Trex 450 heli packs ... 2100mAh 3S 35C and it near ripped the DF unit out !! at 240W and 21A

I tried various packs I have ... some old and some rarely used. It seems the average is 170 - 180W and ~16A ..... which as you see from above is significantly less than my E-Fly 25C packs I used in it previously.

That is why my video shows such good speed / performance I reckon. You cut back W from 210 to 170 ... that's a 40W drop ... just under 20% less power.

I'm now concerned that the 1300mAh packs I have invested in may not be man enough to fly with the wheels at speed. It may wallow a bit.

But the good news is ... with 800mAh Turnigy pack - it balances dead straight with 32gr at back end and wheels fitted.... 440gr AUW
With the 1300mAh pack - it balances with wheels same as the 1800mAh pack without wheels as first flown...... 490gr AUW.
I am hoping that I can play around without wheels etc. and weight at tail end to try and regain some GO !

So it will be trial as soon as the snow and wind stops ......... its -2C out there at moment.

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Old 12-07-2011, 03:43 PM   #20
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OK .... looking at leads from packs ... the reccd 800mAh pack has leads that are half the diameter of the 25C packs ........ indicating that they are going to suffer resistance and probable voltage drop ...

So my advice for these 50mm wonders - go for 25C as minimun ... 30 - 35C is better.

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Old 12-08-2011, 12:22 AM   #21
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I wish I know the c rating of the stock battery! I bought from Banana Hobby and they don't publish that aspect of the battery. Yes, the leads are much smaller than the 1300 mah battery. I have not had a chance to try the larger battery, yet. It is quite rainy.

All of my landings are three point landings if you count the spinner, too
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Old 12-08-2011, 01:18 PM   #22
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Originally Posted by earthsciteach View Post
I wish I know the c rating of the stock battery! I bought from Banana Hobby and they don't publish that aspect of the battery. Yes, the leads are much smaller than the 1300 mah battery. I have not had a chance to try the larger battery, yet. It is quite rainy.
I don't even have to fly the machine - I can HEAR the difference in motor scream between the packs. The 800 is significantly less scream than the 1800 ...

Heres' some other info :

My AUW without LiPo but with wheels = 375 grams
Remove wheels leaving nose servo and mounts = 342 grams

E-Fly 1800mah 3S 25C = 134 grams ... (lightest / smallest 1800 I could find .... )
Turnigy 1300mah 3S 25C = 112 grams
Turnigy 800mah 3S 20C = 67 grams

I know you can add the numbers but I even weighed in flight ready to go form ...

Total 1800mah 3S 25C and wheels fitted = 509 grams
Without wheels = 476 grams

Total 1300mah 3S 25C and wheels fitted = 487 grams
Without wheels = 456 grams

Total 800mah 3S 20C and wheels fitted = 442 grams
Without wheels = 409 grams

So it looks like I will be using 1300 - 1800 WITH wheels and the 800's for no wheels hand launch days. Its the C rating that will decide ........ not the mah ...

Roll on 4S !!

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Old 12-08-2011, 01:24 PM   #23
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Yeah, the difference in the sound is music to my ears! I bench tested it with a 1300 mah, 25c, 3s last night. She now screams like a furious banshee! (as opposed to a mildly annoyed banshee on the stock battery).

Plus, the CoG balances out much more nicely on the 1300, which fits with no modification required!

All of my landings are three point landings if you count the spinner, too
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Old 12-09-2011, 09:00 AM   #24
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Originally Posted by earthsciteach View Post
Yeah, the difference in the sound is music to my ears! I bench tested it with a 1300 mah, 25c, 3s last night. She now screams like a furious banshee! (as opposed to a mildly annoyed banshee on the stock battery).

Plus, the CoG balances out much more nicely on the 1300, which fits with no modification required!
Its nice to hear the 1300 fits the MIG without mod ... the T45 space is too small for it and needed a soldering iron to melt out to enlarge.

Glad to hear you are in the "fast league" now !

Next :

So lets move to next stage ...........
My EDF is rated for 3S lipo - but many are putting 4S in them. having seen that a higher C rated 3S is best to get the magic 200W needed for exhilarating flight ......... what C rating to head for on 4S.

Technically ... 11.1 up to 14.8 = 33.3% increase in motive force (volts).

Motor is 4200KV .... so 3S is = 46620rpm no load, 4S = 62160rpm no load.

Can I play numbers to arrive at desired amps to give similar 210W as I get with prime 3S ?

Ohms law ... 210w = volts 11.1 x amps .... which calcs out to 18.9A ... close to test results.

So taking 210w again and now using 14.8v = 14.2A

I am going to assume that a 20C 4S pack will work better than a 3S 20C pack ? If so then pricing is attractive, pack size is smaller ... I can afford to up the mA from 800 to maybe 1000 or more and fit the space I have.

Need others thoughts / ideas / findings on this ......

Who's gonna be first to hit the 100km/hr with one of these 50mm Mini's ?

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Old 12-10-2011, 11:18 AM   #25
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.........

A little mod that has been niggling away at me to do ... but I keep putting off .... 180 the servos - so arms exit top of wing. That way belly landings don't have the aileron rods / horns etc. caught in the grass.
I'd read that another guy had just 180'd the servos as is and the arms were fine.
Today I did it and he's right ... in fact the servo arms are nice and low and exit enough to attach the z link. The only down-side are the control surface horns are bit ugly. Plus the lacquer paint they use to decorate the model is poor.

Disconnecting and you can see the prominence of the horn etc that without wheels is lowest point of model ! ..







Making servo slot in wing with soldering iron ..



Lining up servo arm / horn ... here you start to see arm is only just proud of wing top ..





Servos double sided taped back into their slots ... horns epoxied to aileron top surface ... rods connected ...





and marker pen to touch up the red ..





I have to admit I made one error ... I placed the horns so that the screw adjuster is on the inside making it difficult to adjust. I should have mounted the horns to have outside ...

Later I may replace rods and connectors with clevis and threaded rod to reduce hardware visible.

At least now I can stay with plastic geared servos and not worry about stripping gears anymore in the grass. I can in fact get white plastic and cover the servos under the wing if I want !

Weather here now is absolutely terrible with strong wind, -2C, freezing rain ... not exactly flying weather ! So mod will have to wait for trials.

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