Help with my first build Gecko 3"

[nicesub]

Hi All,

I started my first custom build (sub 250) and run into issue. I picked Armattan Gecko 3" as my first drone frame and picked for it 1404 XING2 3800KV motors. The motors have 9mm mounting pattern and frame is 12mm. Found out whilst I was trying out to fit of different parts. On the Armattan Gecko page they just say that the mounting pattern is 14XX so I am now really ****** of. They should have just said 12mm and I would pick different motors or go with a different frame. I don't understand why the specs have to be so vague, this hobby is full of tech and sometimes I am shocked how some products have vague spec sheet or none at all.
Now I struggle to find an 14xx motor with such a mounting pattern, as far as I can see most of the motors in this class go for 9mm.

To put it more in context I am building this for freestyle flying, under 250g and 4S build. I have got already 4s 900mAh batteries for it.

Any suggestions for motors?

[ched]

It's always a right pain to match stuff as there are so many things to consider and it's not helped by some manufacturers not publishing accurate specs.

I have not seen the arms but 9mm to 12mm is only 1.5mm on each hole/slot? Could you extend the mounting holes or would that be too much of a compromise on strength?

You might be able to send the motors back under distance selling if a UK purchase and you haven't soldered to them.

[Bad Raven]

As he says       

Not good to have to potentially butcher a frame but currently getting ANY motors anywhere near the model you desire is a lottery.

Faced with your situation, I'd carefully alter the frame holes if there is enough meat to do so.

And dare I say it, using freeable Locktight, and correct length screws that fully use the motor thread depth without over length issues, I'd only use two opposing screws, and monitor the tightness  without overtightening.

[nicesub]

I just gave it a look. No luck, there is not enough meat to extend the holes  .
I think I got my lesson. Next time buy the frame, get my caliper out and take measurements that I need and then buy rest of the stuff.

Anyway, any motor pick suggestions?

[nicesub]

As expanding the holes is not an option I was looking for another motor:
This is my current short list:

• TBS Podracer 1505 3600KV Motor - no thrust chart at all
• T-Motor F2004 3000KV Motor
• Emax Eco 1407 Cinewhoop Motor (3300Kv, 4100Kv) -cant find thrust chart for this one but has a nice stator volume, also not sure should I get 3300 or 4100 version
• BrotherHobby VY 1504.5 Motor 3950kv
• BrotherHobby LA 2005 3450kv - on paper a beast of motor

And this is my prop choice:

• HQProp DP 3x4x3
• Gemfan Hurricane 3016 Props
• Gemfan Flash 3052 Props

Any suggestions?

[badger1]

And this is my prop choice:

• HQProp DP 3x4x3
• Gemfan Hurricane 3016 Props
• Gemfan Flash 3052 Props

I can't really comment on the motor choice as I'm not very familiar with 3.5" quads, but that's quite a range of pitches you have on your props - the 3052 has more than 3x the pitch of the 3016!   

[Bad Raven]

Motors

Choice of kV is relevent to type of use use AND to battery voltage.  Do you have cell packs you want to use, or will they be all new? 


Generally the taller the motor, the greater the torque and the greater the current draw.  So motor choice depends on how you intend to use it. Since you state Freestyle in post one, then extreme diamater relative to low height is to be avoided.

Props will depend upon size AND kV.

Its a circular argument, and all we know is you want to do Freestyle with a 3" frame. Not enough info to say!

Basics for freestyle:-

1. Choose 3 blade props.  So T3x?x?. They are cheap enough to buy several differing pitch and test. Prop pitch is RARELY accurately stated anyway!

2. On a 3", motors would be chosen for 4S, rarer 6S (where 5" quads often are these days), with 3S only for cruising. Motor examples from EMax for 4S include RS1106 II 4500kV on a T3x3x3, or ECO 1404 3700V on the same size prop.  The former will also run OK with high C rated 3S

Do NOT buy too big a motor for freestyle, as throttle control down low will be terrible.

I had some HQ 3" props, useless things that the slightest touch threw blades out of line and no memory to return them to balance. YMMV

With regard makes EMax are usually quite good, but you need ECO freestyle, NOT Cine-Whoop.

T-Motor have a good reputation.

Brother Hobby are a reboxing company AFAIK

Team Black Sheep are the BMW/Audi equiv, you are buying a badge.

NOTE: NOT saying the examples will fit your hole spacing, my EMax 1404 are 9mm!!!

[Bad Raven]

I have just checked all my 3"/3.5" frames.

4 Have two holes at 9mm, two slotted at 9-12mm.

The rest (another three) are 4x 9mm only.

[nicesub]

Motors

Choice of kV is relevent to type of use use AND to battery voltage.  Do you have cell packs you want to use, or will they be all new? 


Generally the taller the motor, the greater the torque and the greater the current draw.  So motor choice depends on how you intend to use it. Since you state Freestyle in post one, then extreme diamater relative to low height is to be avoided.

Props will depend upon size AND kV.

Its a circular argument, and all we know is you want to do Freestyle with a 3" frame. Not enough info to say!

Basics for freestyle:-

1. Choose 3 blade props.  So T3x?x?. They are cheap enough to buy several differing pitch and test. Prop pitch is RARELY accurately stated anyway!

2. On a 3", motors would be chosen for 4S, rarer 6S (where 5" quads often are these days), with 3S only for cruising. Motor examples from EMax for 4S include RS1106 II 4500kV on a T3x3x3, or ECO 1404 3700V on the same size prop.  The former will also run OK with high C rated 3S

Do NOT buy too big a motor for freestyle, as throttle control down low will be terrible.

I had some HQ 3" props, useless things that the slightest touch threw blades out of line and no memory to return them to balance. YMMV

With regard makes EMax are usually quite good, but you need ECO freestyle, NOT Cine-Whoop.

T-Motor have a good reputation.

Brother Hobby are a reboxing company AFAIK

Team Black Sheep are the BMW/Audi equiv, you are buying a badge.

NOTE: NOT saying the examples will fit your hole spacing, my EMax 1404 are 9mm!!!

This is helpful, thank you