SkyWing 48-in Extra 300L Under Development - Page 10 - RC Groups
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Oct 21, 2011, 11:03 PM
Cookie Monster
If you have the supplied motor and X mount,then it sounds like yours is like mine and the holes didn't line up either.
I had another X mount that actually fitted so I used that one.Just mark where the holes need to be and drill some new ones(in the firewall not the X!!),don't worry about a new X mount,not worth the trouble.I have a bag of about 30 of them and although most are very similar,there are some weird sizes out there.
Consider where the prop will be also as the guys have said as there is a fair built of inbuilt right thrust in the firewall.
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Oct 22, 2011, 04:18 AM
Registered User
Thanks guys.
I've marked the locations of the new holes and they are very close to the pre-drilled ones. May end up with extra large holes. I guess this calls for very careful handiwork.
Oct 22, 2011, 05:04 AM
Cookie Monster
Just spin the mount around a bit,no need to drill right next to the other holes
Oct 23, 2011, 11:24 PM
Registered User
Back with another question:

I've got the motor mounted using the included x-mount and screws. There's a piece of EPP that needs to be glued over te motor to complete the cowl.

Is that piece crucial (other than aesthetics)? For safety reason, I would like to be able to check that the motor is not loosened regularly. That cannot be done with that piece glued on.

Will flying characteristics change with that 'hole' wide open?

Oct 24, 2011, 02:10 AM
Just flitting about!!
bigroger's Avatar
Now I got a question for the motor gurus.

I've swapped out my Torque 820kV motor for this one from HK.

Supposed to be 830kV and swing high torque for 3D.

I propped up my apc 13x6.5 and only got 33A, 350Watts.
Apc 14x7 39A and 405Watts.

Is this an indication of an efficient motor or bad motor.

Bench testing the 14x7 doesn't feel like it has much thrust compared to my torque820.

PS. Running 3S Lipo.
Oct 24, 2011, 05:27 AM
Aussie 3DHS Addict :-)
WOOSHKA's Avatar
If you could check the rpm it would give you an idea if it is actually the kv that they say it is
I have never been to impressed with any of the hc motors , ended up reselling all of them
Oct 24, 2011, 05:58 AM
How many planes is too many?
groovejet's Avatar
Yep, agree. I stick to Scorpion motors when I can, though I still have quite a few Turnigy 3542 SK motors sitting idle that I will probably start fitting to planes if I keep buying more as they are a decent low cost way of getting about 2 kilos of thrust for about 45 amps on an APC 12x6e prop.
Oct 24, 2011, 06:16 AM
Just flitting about!!
bigroger's Avatar
Looks like I gotta get me some way of measuring rpm with prop on?

I looked at some of the HK setups that require connecting to power and one of the motor leads to measure the signal going to one of the windings.

I got my scorpion 3020 890kV but I am saving it for the Skywing Yak that is sitting awaiting my next shipment of MG14 servos.

Should set me up with 3 functioning skywing planes and 3 woodies, PA, EF and 3dhs.

Ordered myself a 42" slick on the weekend to play with.

I'll take this HK motor up tomorrow with an APC14x7 and give it a run. I checked and had to cut away some of the firewall around the motor shaft collar as it was rubbing a bit.

Remeasured watts and got 36A and 420Watts on a fresh 3s2200/25C lipo.

Still a long way short of the performance of the torque 820kV.
Oct 24, 2011, 06:29 AM
How many planes is too many?
groovejet's Avatar
Originally Posted by bigroger
Looks like I gotta get me some way of measuring rpm with prop on?
I don't bother personally. I generally buy Scorpion motor after studying the Scorpion thrust charts to pick the right combo for my needs. I generally add 20% to the amps in Scorpion's charts and that's usually about what I measure with my Eagletree. This is due to great advances in lipo performance since the Scorpion chart data was measured.

Basically, I use my Eagletree to get some readings to check that things are within specs and I fly my planes to see if the power is sufficient. One of the luxuries of buying name brand motors is their high consistency from unit to unit. With Hobby King motors I found that I had to test every single unit as the windings seemed very inconsistent, which meant the Kv could vary perhaps 10% up or down from the claimed rating.
Oct 24, 2011, 08:04 AM
Just flitting about!!
bigroger's Avatar
Thanks Groove.

I really like the quality of the Scorpion that arrived today.

The only issue as you have stated before is that everyone else out there seems to love them too. there just isn't much stock anywhere. Even the guys bumped up the price the day after you recommended them to me on one of these threads.

I bet they watch this forum and react accordingly.
Oct 27, 2011, 06:19 PM
Registered User
57sailplane's Avatar
i have been searching to find out what motor to use on this plane. i have plenty of used motors all being of wich are the cheaper but good working turnigy brand. they are either the sk or the old orange series of motors i was thinking of using 3536-1100 but see on this thread that the 3542-1000 is a little shy on performance compared to that of the scorpion 3020-890..

but has anyone tried the 3548-900kv i have one on a glider i have not flown in years. the motors weight is the same, mayby a little lighter then the scorpion, close to the same demensions as the scorpion and should have more torque then the other turnigys.

here is the motor i am talking about.

tell me what you guys think. its cheap cause i already have one. or is this over kill

later andrew K.
Last edited by 57sailplane; Oct 27, 2011 at 09:30 PM.
Oct 27, 2011, 07:05 PM
Just flitting about!!
bigroger's Avatar
there are heaps of options on motors.

My Extra uses the 3715-1000kV from the combo kit and it has heaps of power on apc13x5 or 13x6.6. Draws heaps of amps but hasn't had any problems apart from a bent motor shaft.

The scorpion is quite heavy at 166g, I have one fitted to my Skywing Yak(yet to be flown) and the quality feels good.

You really need about 350-450Watts for this plane. Any more is overkill and more watts drains you Lipo faster.

I say, go with what you have on the shelf if its around the same size and specs.
I am a little like you, still trying to understand motor specs, it seems every supplier have their own way of specking motors, confuses the hell out of me to be honest.

I just ask questions here and see what comes back.
Nov 05, 2011, 04:00 AM
How many planes is too many?
groovejet's Avatar
Nac and I had a great flying session today, despite it reaching 29 degrees celcius while we were there. I had a few mishaps that I'll blame on the heat .

The Scorpion 3020-890 motor on an APC 13x6.5e prop is a fantastic combo for warm days as it doesn't get hot despite me trying very hard to heat it up.

After a few flights of my Extra using an APC 13x6.5e prop, I switched to a Gemfan 13x6.5e prop and the performance was the same as far as I could tell. The vertical climb rate was great, the tumbles were as violent as ever and the flight duration was the same. That's good news for people looking for a cheap alternative to the APC 13x6.5e prop.

Here's a photo from Nac's iPhone.
Nov 15, 2011, 11:22 AM
Registered User
57sailplane's Avatar

i ordered my servos for this plane do you guys think these will work well for the set up.

oh and since i had to order some servos anyway i got one of these also. i have never seen this motor before? seems strange others say the same. its a new wind on an old motor. i think it will run pretty close to the scorpion motor just a little less effiecient.
Last edited by 57sailplane; Nov 15, 2011 at 02:49 PM.
Nov 15, 2011, 04:16 PM
Cookie Monster
Servos seem ok,I just went with the MG14's which have been good so far.
Motor looks good also,although a bit heavy for my taste-saying that though, some of the guys are using similar weight Scorpions,so I think you are good to go.
No real tricks to this one,however I recomend reinforcing the undercarriage mount are with a block of foam and some expanding poly glue.Just slice the EPP along the seams to get at the area.
Also to get the required throw on the ailerons,you will need longer servo arms.
Other than that it is easy peasy and flys nicely.
I don't run the SFG's either anymore,I don't think the plane needs them,up to you though.

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