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Aug 01, 2019, 02:40 PM
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Aug 02, 2019, 01:53 AM
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Originally Posted by gc_ober
I really don't fly my 3" 138mm anymore. I keep it for a travel quad.

I thought I could retire this if my 204mm 2204, changed over to 4" props, would be small enough to fly in small areas and for travel. I tried this out using GF 4052 props. It looks good although the performance is not so great. Maybe it's too low kv for 4". But maybe this is good enough to use 4" for travel.

And maybe come winter I'll resurrect my 130mm frame + 1103 / 1106 parts to build an indoor furniture scratcher.

Trying to reduce the fleet count to justify building another quad.
I can recommend the scooter 135 frame with nk1306 motors (6000 kv and 550mah 3s) and kk 3x4.5x3 props. That combination is so fast - I think its probably my fastest quad. Not so good for inside though . Itís definitely much faster than the 4Ē quads I have using 1507 and 1606).
Aug 02, 2019, 01:57 AM
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Originally Posted by --Oz--
I built a external load for my icharger 306b for DCHG+ mode, it's super simple, 5Ω 100W load resistors (10 of them for 1000W total) and a switch for each to enable them. I built it for 4S, so each resistor is about 3A. Then I started playing with 5 and 6S batteries, so I added a series/parallel switch, it basically breaks the 10 parallel resistors into two banks and puts them in series. Fan is not attached yet. I spent $11 on the resistors from ebay, everything else I already had. I made a simple table to configure it for 1 to 6s, I limit my wattage to ~500Wmax.

I did not like connecting/disconnecting my external load every time, I could of used a switch, but I did not have any 30A switches laying around, so I came up with a simple solution with two banana plugs. One stays in the carger and goes to the load, the one next to it I removed the banana portion and glued it to the other banana and this goes to the other side of the load. Now I just move the banana from the battery from one to the other (load in series or load bypassed), works well and quick.
This is cool! Would be nice to bring the field charging lipo back to storage quickly. I bet this also acts as nice garage heater at charger output .
Aug 02, 2019, 08:22 AM
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Originally Posted by joelucid
I can recommend the scooter 135 frame with nk1306 motors (6000 kv and 550mah 3s) and kk 3x4.5x3 props. That combination is so fast - I think its probably my fastest quad. Not so good for inside though . It’s definitely much faster than the 4” quads I have using 1507 and 1606).
Thanks for the recommendation. I keep all of my old frames and most of them are still usable. For 3" I think I have a 130, 135, and a 138mm currently using 1404. I think these motors need new bearings. Last year I felt my 3" was as quick as my 2204 5". Now it has lost some zip while my 2204 build is significantly improved. I've just lost interest in flying 3 in.

4" seems to be an in between size for many.

My next frame will be a 234mm for my current 2205. This is my first use of 10*9 tubing.
Last edited by gc_ober; Aug 02, 2019 at 05:10 PM.
Aug 02, 2019, 08:57 AM
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Thread OP
I've been spending some time recently back on the sim, while waiting for my finger to heal. Thought I'd take the opportunity to make a start learning to fly inverted with a view to buying a heli in the future.

Man, inverted is hard . Surprised myself how utterly useless I am at picking up it up.
Dunno whether it's because I've left it so late to try, with the positive only throttle pitch use being really ingrained, making it difficult to adapt to negative collective.... Combined with the reversed elevator on the cyclic, it's giving me brain strain.
More likely, I'm hoping, I've just forgotten the painfully slow progress of learning to fly new orientations.
Aug 03, 2019, 01:52 AM
--Oz--'s Avatar
I got an email from CNHL, looks like some batteries are on sale, free shipping on $100 order.

I am guessing HK will have a sale at the end of the month (labor day).
Aug 04, 2019, 03:42 AM
Wut wut wut
Random flying:
2204 Tmotor 5143 (3 min 32 sec)

@Tim Yeah I've been flying a lot in sim, and I was incredibely awful about going inverted and now I'm just awful.. so improving but still long way to go. I guess its just hard to pick up if you don't try it.. like I can't even hover inverted without going all over the place. I've been meaning to like commit to it and just spend entire time working on staying inverted.. usually I do it for 30s and give up, lol. Try again next day or whatever for another 30s.
Last edited by bexamous; Aug 04, 2019 at 04:09 AM.
Aug 04, 2019, 09:46 AM
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Yeah, and the fun with inverted flying comes also with prop selection. It has to be light enough for the motor to reverse it reliably, but also not be too soft that it vibrates at higher RPM. The T5143 from your video is super light and reverts instantly even on a 2204 motor, but it makes horrible stretching noises when spinning WOT in reverse direction
Last edited by Markus Gritsch; Aug 04, 2019 at 09:58 AM.
Aug 04, 2019, 10:14 AM
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True instant reversing for max response without airmode - like yaw without jump - and truly seamless 3D is the holy grail. Once thatís done and I can fly 3D well I will be done with this hobby. In other words still a couple years to go .
Aug 04, 2019, 10:27 AM
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Depends on what "fly 3D well" for you is . I don't think I will be done with it in this life time
Last edited by Markus Gritsch; Aug 04, 2019 at 10:37 AM.
Aug 04, 2019, 11:38 AM
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Interested to build 280mm with 6". In prep I auditioned some Avan Long Range 6x3.8x2 props on a 260mm. The motors used are 2206.5-2700kv and likely too high in kv but this should provide some prop performance expectation and direction for a motor and battery to use on the 280mm. I do have some 2206s maybe: 2122kv or 2522kv.

My first flight was mostly clinical, recording with blackbox. Thrust is good although somewhat uneven, maxing 14.2G punch reading, Roll step response needs some overshoot adj with the PIDs. And I need some filter adjusting on the gyro to clean up what appears to be a high freq resonance. I'm hoping that a 1100mah, 4S battery can be sufficient. I'll make adjustments and fly some more for feel. I also need to accept the prop non-colors for LOS.

2700kv is definitely overloading the motors. In spite of this the 6" dia. efficiency is apparent. I'll likely first try 2206-2122kv motors.
Last edited by gc_ober; Aug 04, 2019 at 08:04 PM.
Aug 04, 2019, 08:19 PM
Wut wut wut
BTW the greatest 6" prop: $0.15/prop:

You gotta order green cw, green ccw, orange cw, and orange ccw... I got 15 of each for $21 shipped... I almost want to buy more.

Not crash friendly though, basically every crash is a broken prop.

Also these arn't people's fav, but still super light 2306 motors and they're kinda on sale:

I currently have my main 6" quad, RSII 2306/2400kv motors.. think its more like a 6.5" frame. I then got an old 7" 10x8 tube frame I bought a set of Hyperlite 2207.5/2222kv motors for.. plan to run that on 6" tris too. And then I saw the Emax motors on sale so I got two sets of them.. not sure what I'm going to do with them, lol. I took an old 7" frame that broke near moto, shrunk it to like a ~6" frame.. but man built it up and 6" props jsut barely don't fit. Its a few mm too small. Doh. Might just build two 6.5" frames with 8x6 tube... I mean it takes me like 4 months to build a quad now. I always choose to go fly and leave parts on bench waiting for a rainy day.

2306 HQ6x4.5x3 850mah (5 min 26 sec)
Last edited by bexamous; Aug 05, 2019 at 01:39 AM.
Aug 05, 2019, 09:23 AM
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That big quad is good for video with the bright color props. Nice flying also.

That's a cheap 6" prop for sure. but at 4.5g for a 6" tri-blade I wouldn't even try it.
I'm looking at 6" bi-blades for lower inertial moments for a smaller motor and battery: the Avan at 4.9g and GF6042 at 4.8g. The Avans had a unevenness to the acceleration curve and I'll try out the GFs today. I'm not too concerned about this until I get the motor kv to a decent range.

If I get my 280mm build with a 2206-2122kv light enough, an 850mah 4S might be OK given the increased efficiency of 6". I don't think I'll improve anything in performance or responsiveness over my 5" but the sound of a 6" bi-blade under throttle is neat.
Aug 05, 2019, 11:58 AM
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Tubular 234mm frame for 2205 is built. I will make a transfer of hardware from an existing 208mm frame. I want a slightly bigger frame for this and also gain experience with slight change in the center section to increase strength for bigger frames.
Last edited by gc_ober; Aug 05, 2019 at 12:04 PM.
Aug 05, 2019, 12:49 PM
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Thanks everyone for the great thread!
Too bad it's only %20 ultralight/tubular, and 80% other topic (quite interesting but still...).
I have some ideas I would like to discuss.
I think fiberglass tubes have potential for quad arms, they are not as stiff as carbon fiber, but they have better toughness (impact resistance).
For source I would look for arrows - cheap ones are fiberglass. They also has different diameters and materials - including aluminium, carbon, and aluminium/carbon hybrids.
For epoxy, if there are thick layers/fillets, it's good to use fillers like microballoons/microspheres - they are lighter and also stop crack propagation, making epoxy not so brittle.
Also some random idea - crush motor wire near strain relief, providing "breakaway" point so it will not lift pads from FC.

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