Deathly Hallows - FW - Alligrater

[Deathly Hallows]

Thanks to the help of Paul I got the linear control working. At least this mock up, which powered a small 12V motor. The idea is to make a sandwich with some polycarbonate as the bread and the microswitches as the filling. Conveniently the mini servo I am using is just the right height to align with the arms.
IMG_20180616_141311.jpg
IMG_20180616_141330.jpg

I need some long 4mm bolts and some longer 1.5mm bolts, and in the final version the polycarbonate will shield the arms too. (Pictures updated with bolts fitted)

[Deathly Hallows]

Got a few deliveries this week.
Bolts, nuts, titanium plate, polycarbonate

I am going to make the top mostly from polycarbonate as it's light, also it's cheap to replace so no big deal if destroyed after each event. I'll add reinforcement behind.

Did a little more work on the electrical system. Configured the buck voltage reducer to put 18V to the lineac.
Added a 'live' light, a 100A fuse for lipo and a kill switch/jumper

I am making a polycarbonate lid for the bucky and adding a fan to be sure it can handle max load.

[Deathly Hallows]

Here's a video of my lineac controller working

[PaulusSmallus]

Its looking really good I am excited to see it all together.

[Deathly Hallows]

Its looking really good I am excited to see it all together.

Thanks very much.

I added some titanium plate to the front instead of that bit cardboard . It weights in at 13.02kg so once the ramp is fitted it's going to be a bit over but lots of opportunities to lower weight.

Having some electrical issues. Got it all wired up, motors spinning, lineac running, but something is not right.

[PaulusSmallus]

What is wrong with it?

[Deathly Hallows]

I am not 100% sure.

The power is down.
The Feathertwo is making a tone when operating the motors (I think sound is coming from the ESC)
It moves forward and back but not turning when on the ground, but works properly when on stand.

I have 3 fuses all at moment under sized for testing and none are blowing. A battery fuse 30A, a ESC/motor fuse 30A and a lineac fuse 15A.

Very odd. I sent a PM to Rapid Rory

Two thoughts:
My shockingly bad soldering (the kill switch was getting very hot)
The RX is sending bad signals to the ESC

[PaulusSmallus]

Is the kill switch getting hot when you try to move it on the ground, or are you meaning it got hot when you soldered to it?
Do you have a multimeter?

[Deathly Hallows]

Is the kill switch getting hot when you try to move it on the ground, or are you meaning it got hot when you soldered to it?
Do you have a multimeter?

It gets hot when running. Actually smoked.
It's a anti-spark XT90 with awg10 wire across the pins.

Yes I have multimeter

[Deathly Hallows]

Found first issue. A connection in the XT90 kill switch was not sound so could only carry so much power before it maxed out. On the ground the motors pulled more current so they stalled.

There is still a tone from somewhere. I think the ESC but seems ok.

Running up the motors at higher speeds the chain jumped. I need to fit a tensioner, I thought I may need to. I have some ideas.

Also played with the trim. Not really sure what I am doing here but moving channel 1 to the right of centre seems to have aligned the drives a bit better. Once the chain tensioners are fitted I'll give test it on the ground.

Still need to fit the wedge ramp too

[Ocracoke]

There is still a tone from somewhere. I think the ESC but seems ok.

I has this issue on my FeatherTwo, it is the trims that need setting on the controller. My axe on The Honey Badger 2 used to provide a little bit of power in reverse so adjusting trims made it stop making that noise.

[Deathly Hallows]

Fitted some tensioners. I had ordered some track bike tensioners in case.

IMG_20180617_193903.jpg

These worked really well! So I thought I'd give it fill power on the stand.
WhirrrrrrrrrrrrrrrrrRRRRRR
CLUNK!

Chain off on the other side. But how? So much tension?

I could see the chain had hit the frame.
IMG_20180617_193921.jpg

But the gear should not be that far over. Time for a total disassembly

Initially I thought the bolt had sheered off.
IMG_20180617_194920.jpg

But no. I'd only used regular nuts when I didn't just build up, planning to swap them out for locking nuts before finishing and I'd forgotten.

But with the whole front, body, wheels out no video today.

But I'll take the chance to make some improvements and lose some weight.
Drilling the wheels
Drilling the floor
Cutting a piece out the floor
Widening the wheel slots
Swapping out nuts for locking nuts
Tightening up

Need to get this done fast as I have not yet tested the lifting arm.

[Deathly Hallows]

Today I stripped it right back.
I cut a 12mm strip off the front and sides leaving some pieces as a ledge for the HDPE armour.
Widened the wheel slots a bit,not much weight saved there.
Also drilled a heap of 10mm holes in the base and some 50mm holes in the HDPE sides and back.

I also cross drilled all the rubber of the wheels but to be honest I saved very littleweight. I think the weight is in the hub.
While I had the wheels out I checked the fitting and replaced those pesky nuts with locking nuts.
Refitting the wheels on the axles took about of work but I am happier in their location,and the clamps are tighter to stop movement when rotating

Swapped out the motor retaining nuts for locking nuts.
Tightened everything else up.

I should have shed perhaps 200g. Fingers crossed.

Refitting it all back together now. Fitted some of the pond filter foam around the electronics, and under the battery. Tidying up some of the cabling.

Tomorrow I want to refit the shell,and test everything still works.before bolting it all in place again. Then it's fitting on the front armour and building and fitting the ramp, including the self-righteous mechanism, and sides.

I could do with a day off work.

[Deathly Hallows]

Having a total nightmare!

No matter what I try with the tensioner the chain is jumping. Tried shortening chain and it would be too short.

Tried the tensioner lifting from below today. Same problem.

Spent hours today on this, beginning to think I may need to try something completely different.

It's a shame as I received the Grantham email I citation today too

Anyway no time to write more. Back to the Robot Shed for me

[Ocracoke]

I can only think of either the chain being out of alignment or a bent tooth on one of the sprockets.