Large Pylonish Racer. - RC Groups
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Oct 23, 2006, 01:49 AM
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Large Pylonish Racer.

Aero-nuts 4120-710 Outrunner


Input Voltage : 7.4V~18.5V (2~5S Li-po)
Kv : 710 rpm/V ±10%
Nb. of turns : 12 Delta
Max. efficiency current : 25~40A
Current capacity : 55A/60s
Internal Resistance : 22 mohm
No Load current @ 7V: 2.67A
Dimensions : 50mm X 55mm
Shaft diameter : 8mm
Weight with cables : 301g
Number of poles/magnets : 14
Recommended model weight : 2000~4000g

Its the motor on the left of the large one.
I want to build a racer with a ABC 9X9 prop on 4S.
Here is the data on the batts.

Aero-nuts 4S1P 14.8v 2200mah 16C Continuous Li-polymer.
Weight : 249g with 12AWG wire
Size : 105 x 34.5 x 35.5 (mm)
Continuous current : 16C/35.2Amps
Burst current : 20C/44Amps
All Aero-nuts batteries pack come with balance connector and T-Plug

So :
Motor 301g
Batts 249g
total up plus esc is 584g or 20.6oz or 1.28pounds.

I need a plane scratch built simple box fuse and built up sheeted wings. Based on power package how much wing my guess is about 46 to 54in span.
Heres the data on a APC 9x9 with this motor data base only till the gear shows up.

est:87mph 2.86lb of static thrust.
31A and 475w in, on 4S and 329w out.
The motor can handle more I just cant pony up for the batts right now.
I would like to move up to 5S and a APC 10X10 That would get me around 105mph pitch speed.
Who has any insights into such project, I could use some input.
I wonder if I can make the plane strong enough and around 3.4lbs ?

Im stuck with these batts to work with I may gut the wire and rewind the motor after I test in stock form.
AbCaBc leave it 14pole and use 20g to keep the amps around 35. And bring the kv to 1250 on 4S for 120mph tip speed with a APC Sport 7X8. Thats doable, whats going tobe tough is to hit close to 90mph. I need just enough wing for the job and keep the box fuse skinny/light and strong. I dont want a lead slead on landings there is alot of motor on the nose 0.7lb. and prop and spinner weight. Any bad tumbles will cause instant damage im sure.
Last edited by Amp User; Oct 24, 2006 at 01:27 AM.
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Oct 23, 2006, 02:56 AM
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Im in luck I dug out a APC 8X10 I can cut it down to 7.5X10
2lbs static thrust
133mph pitch speed.
Oct 23, 2006, 12:30 PM
Flying motor mount master
fly_boy99's Avatar

I don't mean to diss your setup but most folks who play in this space look for high Kv motors. You have chosen a

Kv : 710 rpm/V ±10%
Motor which can get up to some speed by using alot of voltage. Maybe look for a higher Kv motor or rewind yourself as you have stated.

Oct 23, 2006, 02:40 PM
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Yes totaly agree, alas I must do a review on the motor in stock form before I can transform the motor into a rip snarling high Kv beast.
Oct 23, 2006, 03:37 PM
Speed Demon
GregG's Avatar
Originally Posted by Amp User
.....I need a plane scratch built simple box fuse and built up sheeted wings. Based on power package how much wing my guess is about 46 to 54in span......
I need just enough wing for the job and keep the box fuse skinny/light and strong. I dont want a lead slead on landings there is alot of motor on the nose 0.7lb. and prop and spinner weight. .....
Building something from balsa as you describe makes me think of a downsized Quicky 500 model. In my mind 46" span might be on the large size to make high performance for the power system mentioned.
Oct 23, 2006, 06:48 PM
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Yes I might be able to drop down to 38in span if I can keep the all up weight under 3.2lbs. In the motors current state, I can only nudge about 1.7lb of thrust to preserve some speed.

Ok Im looking at 35a 14.4v so bottom line is the output of a 25 size engine. So much for jumbo, unless I build very light. Should be intresting im going for it will keep you posted. Looks like I can stick with something near 48in span with a med/high aspect ratio. 9in at the root X 48in heavy tapper.
This will allow for a reasonble size racer for the rewinding later.
Last edited by Amp User; Oct 24, 2006 at 01:04 AM.
Oct 24, 2006, 02:43 AM
dessertracer's Avatar

I'm currently working on a 48" scratch-build racer. It’s built from layered balsa with glass and carbon weighting 8 oz and having 230 in2 wing area. I'm starting off with a Mega 16/15/3 on 3s with an APC 5 x 5 prop and will upgrade to a larger power system later. From what I've seen with these things you can get 80% of the speed for less than half the thrust and power.

I'd love to hear how your project progresses. Building is just so much fun (and addictive). Your power system is definitely a large one—much heavier than mine. Have you considered going larger like 72” wingspan?
Oct 24, 2006, 02:47 PM
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Yes I really need the motor and batts in hand to get the feel for a design. I too will be upgrading the batteries or rewinding for more power later so I really need enough plane for the job in the long hual. This motor is able to produce the power of a 40 size engine so I need to bare that in mind. For now I can only afford enough batteries to make it a 25 size. I was told by PanLau from HongKong the gear will show inbout 6 more days. I may go huge if the gear looks/acts the part.
Oct 29, 2006, 02:04 AM
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Welp I now have the motor and batteries in hand and can get a feel for the design, heres what showed up.

Stator is 40X20mm with 22X6X2mm mags
12arm 14poles and 10strands of 28g wire delta.
55X49mm motor over all size minus prop mount.
The lams are thin like its litttle brother a big plus.

Im going to try to load for 28A static at wot, in the air I should be in the 23A range. There should be enough juice to get 10min flights or 6mins at full throttle.
Oct 29, 2006, 04:48 AM
dessertracer's Avatar
Cool looking motor. Is that a gas prop bolted on?
Oct 29, 2006, 08:39 AM
Speed Demon
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That is a cool looking motor , however it's a real monster of a size when it comes to building a small go fast plane around it. It weighs in at 310 gm (~10 oz) and the diameter is 50mm (~2"), that's a hell of a lot of mass.

As has already been said, I don't want to rain on your parade but I'd think one would do much better to use that motor in a sport application and go towards one of the smaller lighter motors to build your go fast plane. Afterall, there are 1-3 oz motors out there nowadays that are used at 300+ watts. These lighter motors are also smaller in diameter. It might be something to think about.

I'm sure that you'll be able to build a plane that will work well with what you have. I'd never try to talk anyone down or stop anyone from trying. If this is really what you want to do go for it. I just wanted to say that there are easier ways to do this, that motor makes it kinda tough for you.
Oct 29, 2006, 08:44 AM
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I'm with Greg - to go fast on those power levels, you need a smaller model than that motor will allow. To go fast on the scale of that motor, you need to be looking at power levels in the 700-1000W range..

The motor you have there looks like it would do well on the OLD Hobby Lobby Dynamic -

Oct 29, 2006, 12:04 PM
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Yes its not going to be a easy task on just 400w well under the motors ablities.
So I will build the plane and test fly on less power till funds allow more thrills. 2200 5S2P would get me in the 850W range 19v x 45A with the stock wind. I need to buy 1 5S1P and 1 extra matching 2200 cell for my 4S1P pack. There is of course the option to rewind.

Hey Desert racer the prop is a 14X6 gaser prop just half thrown on there for effect of size. It does spin that prop with ease on 3S too much load on my 25A esc on 4S.
Last edited by Amp User; Oct 29, 2006 at 10:19 PM.
Oct 29, 2006, 12:06 PM
Registered User
Another outrunner from China? I cannot see which motor is going to be used? or all will be tried or sold in the market now for pylon racer of special design nose? Is it to be geared with inline gearbox? NEW desgin hv outrunners, it shines with the blues, pretty.
Oct 29, 2006, 12:47 PM
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This one is from Aero Nuts, located in Hong Kong =) $61 free shipping. I fired up the motor on a charged 3S pack just to see how smooth it runs. It spinned a 8X10 apc at 7300rpm 9.2amps/very smooth running motor. Will set up the 4S pack next. I will be ordering some APC 9X9's on 4S for around 10K.

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