BetaFPV 75mm 7x20, 75mm 8x20 and 85mm 8.5x20 whoop frames


#1

I built the 75mm 7x20 version with BetaFPV 17.5K motors and F3 FC w/OSD and it was lethargic and pretty disappointing with the recommend 230mAh batteries compared to my Beta65 and Beta65s. The 260s weren’t any better and both batteries got extremely hot and only gave about 2m flight time and I’m sure it was killing the battery longevity.

The 75mm frame was built for much larger batteries like my eflight 550s but they were just a tad too big for the holder. Then I noticed BetaFPV put their 1S HV 550s on Amazon so I ordered a pair and they made a tremendous difference. It’s like night and day for punch. Plus I get over 4 minutes indoors and about 3 minutes ripping around the back yard going full out as much as possible. It’s an entirely different quad. The IR of the 550s are about 83mOhms compared to the 230’s 120mOhms so the 550s are delivering the current the 7x20s need. I likey!

Anyway, Amazon up their price on the 550s by $2 a pair to $17 (in one week). While looking for the better price on the BetaFPV site of $13 a pair, I noticed they have the 75mm 8x20 and 85mm 8.5x20 versions of the whoop frame (which by the way the 75mm 7x20 frame is extremely durable).

Since they stock the motors and props for the 8x20 frame, I was thinking of picking up a frame, motors and props to test out when I order some more 550 batteries but I wanted to ask the folks here. What would be the benefit of moving to the 85mm 8.5x20 frame and motors? The 85 also goes from 40mm props (75mm) to 48mm props.

Would the 8.5x20 be more efficient for longer flight times like my Blade QX2 (6+ minutes) or would it just provide more power and less flight time?

I guess I could order both and try them but dang, a guy can only have so many whoops, right ?!?


#2

I’m down the same path… first built a 7x20 betafpv (with some motors I had laying around), and found it nice, but lacking in power in some situations. So, built an inductrix fpv* frame with betafpv 8x20 motors, betafpv f3 evo controller, and betafpv 550 mah batteries. Very enjoyable to fly outdoors in moderate breeze ( live near the coast in florida, always have a breeze!). Also pretty durable, but betafpv frame looks more rugged.
Now the order is placed for more 8x20 motors, a betafpv frame, and 2 betafpv frames for 8.520 motors. Have flown picnic quad 110mm brushed frame with 8.5x20 motors and love the combo. the acro naze controller is aging, though.
Betafpv is on Amazon, but I only found the bigger frames on their site (betafpv.com) and shipped from China. So, still waiting to build the larger frames. Should work very nicely outdoors, based on the inductrix 8
20 frame I already built and tested.
Good luck on your build(s). No, you can’t have too many whoops, can you?


#3

@FctryFive2175, good to hear your ducted 8x20 flew well outside. I went ahead and ordered the 75mm frame and motors for the for 8x20s and the 85mm frame as well but they were out of 8.5x20 motors. A day after ordering from betafpv.com, I noticed that Amazon now sells everything I just ordered from China. Oh well, patience is a virtue, lol!

Looking forward to some comparisons.


First time buyer, Indutrix FPV + Question
#4

whats the link for the frame you ordered for the 8 and 8.5?


#5

Not sure if it’s proper to link to outside vendors but just google betafpv and you will find their online store. I noticed Amazon has the frames now so you can get them in 2 days which will be about 2-3 weeks before I get mine from China :slight_smile:


#6

haha, yeah… amazon is a life saver… sorry to hear about that lead time for ya


#7

The 550mah batteries are awesome for the Beta 75.


#8

Those look nice. a little extra power over the stock 500mah.

@wes looks like the estimated shipping time for the amazon supplied one is end of Jan to mid Feb…


#9

@SharkShrank, they had 20 of them for 2 day shipping a few days but today there is only 4 of them available today for delivery on Monday. Anything over that, I’m guessing come from China… ugh!

Glad I have my 8 already!


#10

@CRayTech, I checked out your video and am surprised that you get 5 minutes out of the 550s but then I noticed that you flew down to 2.6V so I have a couple of questions about your Beta75.

  1. What is your low voltage warning set at?

Mine was set mine at 3.0V as default

  1. Do you run until it drops from the air for this test or did you land with controllable power?

  2. What is the weight of your Beta75 without battery?

Mine is 32.1g

  1. Is yours a BNF?

I built mine before the BNFs were available so it’s all BetaFPV parts (with 17,500 KV motors) except I have a Wolfwhoop P-1 AIO on it.

Thanks!


Setting up betaFPV 75. F3 fc w/ Crazepony FPV Micro AIO Camera
#11

I have my voltage warning set to 3.2 from the default of 3.3v. I fly for a few minutes then touch down to see what the battery voltage is at when the quad is at idle. You can see me land for a second in the video. The voltage raises up to 3.7 I believe so I flew a little longer. Voltage readout on the batteries was 3.7 and 3.59v I have the osd setting for the battery at default so the read out may be inaccurate during flight. I’ll have to weigh mine out. It’s bnf stock with the z01 camera.


#12

I only recently discovered all these new frame options on the BetaFPV site. Of course I had to order a stack of each size :wink:

I already have a few Beta75s frames here, and these are built like a fortress!
I get OK performance out of 0720-14 motors, Rakonheli 40mm triblades and 255mAh HV mylipos (fitted with foam adapter).
This quad is only 4-5g heavier than a 7x16, but has significantly more prop surface.
Flight times are not much above 2 minutes.

Its flying a lot gentler than a 7x16 or 6x15 Whoop. And it crashes like a tank. I think you need to run it over with a car to wreck the frame. I hope that with 4-bladed 40mm props and 0720-12 motors, we will still get enough performance but more flight time. Should make a great beginner quad.

Still waiting for the 8x20 and 8.5x20 frames. From the pictures, I assume they are as good as the 7x20 frame. 40mm 4-blade prop option looks good, but the 48mm 3-blade for the 8.5x20 looks like that inefficient 40mm 3-blade.
Should be an exciting box to open :slight_smile:


#13

With the BetaFPV 550mAh 50/100C batteries, I get 4+ minutes on the 75 and right at 5 minutes on the 75s using smooth throttle control around a indoor track. Got 5:38 on the last battery today. 75 is a good indoor machine and the 75s is just a little much for me indoors without toning down the throttle limit about 20-30%. They are “fun” sized whoops :slight_smile:


#14

Anyone know if cockroach is working on an 8.5 frame ??