Just finished a new machined 6" frame.

The first one was 23 grams for the frame but was a little spindly so I made a few more out of 6mm thick carbon fiber plate.  The result I am quite happy with because it is only 32 grams for the frame without compromises- very stiff and no resonance. 

Build list:

32gram custom frame(my own design)


Tmotor 2203.5/ 1500kv motors

crossfire nano

vista with nebula pro(not naked)

flywoo mini gps

axii antenna

gemfan 6026 biprops

Depending on the setup, you can get quite light.  The frame with motors and AIO fc was only 140 grams...

 

closeup showing integrated gps cutout and gopro mount:



Underside with 3d machined cutouts to reduce weight:



Base frame weight:





I tested it out for short flight around the house last night and it flew really nice!

That looks awesome!

I love seeing builds with custom diy frames.

Wow. Nice frame arm holes.

32g is VERY light.

1yr+ ago, I drew up couple 6" toothpick frames for 2204-2305 motor. At first, similar to
https://www.facebook.com/113882796717631...l/?app=fbl

But screws and joints suck. So I made it unibody.
Generous area around motor holes, and then V arms (two 6mm wide) arms cross braces going down to middle like star shape. It was calculated to be 45g.

Finally, it was overkill and expensive as unibody. I was hoping to find 1400kv 23xx so I extended the arms to 7".

This is awesome man nice job!! I had a similar thought with holes in the arms but never went ahead with it. Curious to hear how it works out if there's any resonance issues for you.

Hi gt40,

Yes, the frame is REALLY SWEET.  Mine arrived yesterday. Thank You. 

I was wondering how you secured the GPS unit into that hole ??

Looking forward to more pictures. GOOD JOB   

Keep us updated with progress.

Update: Swapped the super light TMotor 2306.5'/ 1500k for the Stan Fpv/tmotor 2604's  They are similar in kv but more power, albeit more weight.   Went from 4 amps to 6-7 on slow cruising but it is so more fun to fly.  DId  30 minutes  worth of laps  around the house with a Go Pro Bones onboard and got bored with battery left.  I will see what it ends up with for flight time but here is a short cliip with the bones in 5.3k and an ND filter. Not seeing resonance- super happy with how stiff the frame ended up.  I used the stock 6" preset superfly in betaflight with decent results but I have a little prop wash to tune out.

What is your auw? And what speed are you cruising at??

Here is the breakdown:


That is with a 4s 21700 battery pack.  I haven't weighed the Go Pro Bones but it is listed at 64 grams so adding that would put it at 586 grams all-in with the camera.  I didn't log the speed data but saw speeds in 30-40 range and the rapid climbs didn't catch with lion batteries.   Also tested it with a 6s 1550 lipo battery and it was a different beast all together.

Are you really getting >30min using a 4s li-ion 21700 with an AUW of 586g? I do have a similar setup, and i‘m just getting a bit over 20mins. Thats also what eCalc says for this setup, which is 24mins on hover, with a rather low thrust to weight ratio of 2.2. Also, using 21700 cells did not change my flight times at all… the increased weight made up for the increase in mAh.

Not saying i don‘t believe you  . Just trying to figure out what i might try to improve my results.

Sorry for the delayed response, Had surgery last week and haven't been doing anything much. On the mend now though. FYI, your battery choice matters- I ran a custom 4s battery pack with some 5000 mah Molicels. I did see increased flight times if your flying is single digit amps on the current. Also the bi-props added to flight time. I tried to duplicate the flight doing laps and hit a branch on my property while getting bored - SNAP- broke an arm on the frame. I will probably cut another 6" frame and let you know after it comes together.

If you dont have thrust stand, or other fancy equipment how can you tell if props are more efficient or BLHeli settings are better. There is too much variability in doing "random fly around".

But, you can't just hover 20cm off the ground - you want realistic numbers.

What I've come up with:
1) Plot a roughly 850m lap course. Fly about 60 sec per lap. 16.6m/s is 60kph - a good typical cruising speed for small quads.
You can see in OSD, how much mah you are using per lap.

2) If your hover is 18% and good cruising is 26%, you need to find a weight you can strap on, to make you hover 26%.
This "weight" can be just a bigger battery. Now, you can optimize for which prop/motor/etc is best at this 26% hover.