SnapQuad/KK build thread.

[Cabe]

Just remember, although you can put 10" props on that frame, its a really good idea not to. Its way too light for 800g of static thrust at each corner

 

[matwelli]

try 4S and 1.3 kg thrust per corner on a 1000g quad

 

[Droider]

How do you know how much thurst there is?

 

[Cabe]

That might not be far away.

http://personal.osi.hu/fuzesisz/strc_eng/index.htm its not foolproof but its good for ballpark figures.

Using the figures of 10" x 4.7 pitch x the maximum possible RPM of a 750 KV motor on an 3s (11.1v/8325rpm) battery at 68 deg F (20 deg C) gives me between 800 and 900 gms of thrust depending on the prop.

 

[Droider]

Right.. can see the software but how do you know rpm or am I being dumb... and even dumber to ask whats the picture of!

 

[Cabe]

Not at all, your motors will be rated in KV (mine are 750) which means thats how many RPM you get per volt of battery input (in a perfect world, they aren't 100% efficient)

My 750KV which are run on 3S (11.1v) will get 8325 RPM at full throttle....in a vacuum (no load) and 100% efficient. I would bank on them being around 80% or so, meaning mine will probably actually give me 650-700gms of thrust.

The picture is of an aluminium hub and some plastic engine mounts I scored off of ebay. They are built for 10mm alu box and come with a power hub plate.

 

[Droider]

Ahh you learn summat new everyday.. I go have a go..

You building another with that plate then?

 

[Cabe]

That's the aim, with longer arms and probably a paired pack for longer flight times.

The Snap Quad is a gateway frame, snares you with simplicity and then boom, sooner or later you are modifying Octa's with carbon fibre props.

 

[Droider]

Blimey I am getting 1.7kg per motor and I have 6! thats at 80% efficiency. Guess I loose quite a bit as I am coaxial.

Dave

 

[matwelli]

i have found 170 watts per 1 kg thrust is a good ball park figure, some setups (low rev) are more efficient, i also know that the flycam 925's on 10 by 5 props and 3S do aprox 800 grams (tested on scales and on 4S they did just on 1.3kg (also on scales)

it takes 55 watts to hover one 1kg

with motor eff 70-80% and props down in the 40's , 32% overall efficiency seems to be where it all ends up

 

[matwelli]

dave - sorry to hijack the thread, whats the YAW control like with a Y6 ? tried a Y4 and was very disapointed

 

[Droider]

I think its wanderd off course a fair ways anyhow.. but no problem mine yaws just as fast as you could want and I have mine toned down in my TX expo

 

[Bartman]

all y'all are starting to sound like you know what you're talking about!

 

[Cabe]

You take that back!

If people know I am useful they will ask me stuff, and that usually leads to doing. Most people know I do as little as possible