Strix 2

After Strix 1's performance at Insomnia this year, it was clear that the design needed some big upgrades for it to be effective. I was happy with Strix 1's appearance, its durability and its low front wedge, but there are serious flaws which can only be properly fixed with a fresh build. Strix 2 looks quite similar to the first version, but it's pretty much going to be all-new. I'm only recycling a handful of components.

Here is the CAD after spending far too long tinkering about with it.

Attachment 8605 Attachment 8610 Attachment 8608 Attachment 8609

These are the most important upgrades:

New Wheels - Definitely the biggest issue with the original was that the black Bearing Boys wheels were pretty awful. They had barely any traction at all which made Strix very sluggish in the arena. The new wheels will be made from large 80mm HDPE rods and use bike tyres for more grip.
New Drive - Originally I thought that the old Argos 12v drills, which I use in both Strix and Venator, would have plenty of speed. Venator used to be one of the faster featherweights at the live shows, but it was pretty outpaced and Cheltenham this year. Have been really impressed with the speed of Barrog and Plastic Fantastic, so I'm going to upgrade to the new model 12v argos drills on 5s.
Custom Linac - So last build I didn't have enough time or experience to make the custom linear actuator. But for this build it's going to be one of the first things I take on. I'll get all the precise gearbox parts properly machined this time so it should actually fit together. Just like before it'll use a brushless Overlander BM600 running on 5s as that had plenty of punch.
More Internal Space: This wasn't an issue in the arena, but the original Strix was awful to work on in the pits as the guts were so cramped in. I've tried to space things out a little bit more this time, with some 3D printed mounts to save space and keep things tidier.

Armour panels are all HDPE, a mix of 20mm, 10mm and 8mm. Front wedge will be 4mm Hardox. I haven't done a weight calculation yet, but considering the original's weight, I suspect Strix 2 will be right up to the limit. :)

I'm hoping to get Strix 2 finished in time to apply for next year's featherweight champs at Insomnia. Because I'm a bit slow at building these things, I plan on getting most of the parts water jet cut.

This looks really fantastic! Strix was definitely one of the unluckier bots at KOB UK this year with the linac woes, but the design always looked solid to me, and this seems like it should hopefully fix the problems of the original to boot with enough time for testing. Wish you the best of luck with the build!

CAD renders are looking might fine for the new Strix! However, please may I offer a quick work of caution on the new 12V Argos drill motors on 5s. I broke all 4 of mime on 5s inside 2.5 events, they were just not coping well with the near doubling of voltage. I do run them hot despite the vent holes in the bot but they didn't hold up for me. Maybe running them with more free air around them to cool them, a different ESC, or more sympathetic driving would have helped them last. Since replacing them with new ones I have done a further 4 events with them on 4s and *touch wood* haven't had a single issue with them. On 105-110mm diameter wheels I have still found it to have decent speed and power.

Good luck with the build, looking forward to some updates!

@Shooty Cheers mate, hopefully it all goes smoothly!

@Alan Thanks for the heads up - was it the gearboxes that broke or the motors? It was when I was watching videos of ER Cheltenham that I noticed how quick PF was - was it running on 4s there? I did suspect 5s might be pushing it a bit, why can’t you reduce the speed of the motors via transmitter mixing? One extra reason I wanted to go 5s for the drive was to avoid two separate links/leds/batteries like in Strix 1, which ran on two different voltages. I'd rather not go down that route again.

In Venator I ran the old 12v drills on 4s for ages (even turned it up to 4s LiHv in Strix 1) and never broke a single one, so I think you should be ok there. :)

Quote:

---

Originally Posted by dotDominic

@Alan Thanks for the heads up - was it the gearboxes that broke or the motors? It was when I was watching videos of ER Cheltenham that I noticed how quick PF was - was it running on 4s there? I did suspect 5s might be pushing it a bit, why can’t you reduce the speed of the motors via transmitter mixing? One extra reason I wanted to go 5s for the drive was to avoid two separate links/leds/batteries like in Strix 1, which ran on two different voltages. I'd rather not go down that route again.

---

It was the motors that broke every time. The gearboxes seems pretty good and I'm still on the original gearboxes that have had the abuse at both 5s and 4s. At Cheltenham it was on 4s. Tx mixing/trimming would be a good idea for running at 5s but unfortunately for me, I don't think I can do that on my Tx, its only a fairly simple Dxe. It would be good to see how the motors last set up like that.

my bot was running on 4s mainly at cheltenham and portsmouth, and throughtout the testing phases between, all were ok. I went to 5s on 2 fights at cheltenham, and yes there was an obvious increase of speed, i ended up reducing top speed on my tx range as i found it a little too uncontrollable, especially when turning on the spot.
So it is a toss up on how experienced a driver you are compared to top speed. i think 4s is a good start and maybe progress to 5s when you have had experience driving that particular bot.

Cheers for the advice guys :)(apologies for late response). Sounds to me then that full on 5s power could be difficult to drive anyway so I probs will change the trim settings. I’ll leave enough space in the design for any alternate battery setups if this doesn’t work out.