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So, What Have You Done Today?

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11 minutes ago, Thommo said:

 

My wife calls this site "Nerdclub"

Meh...   Could be worse! 

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Made this crazy contraption:
K7N5QVv.jpg

What we have here is effectively an inertia hub dyno to measure motor power/torque. The wheels act as the flywheels for the dyno, made out of layers of laser cut acrylic bolted together - the first layer has a 12mm hex hole, the second layer has a 4mm hole for the wheel nut and the last two layers are just added mass.

I also added 64 slots to one of the layers so when it is painted black a laser shining through it onto a photodiode can act as an optical wheel speed sensor. I floor the throttle and capture the wheel speed signal on an oscilloscope, which is then analysed by a PC. The added mass of the 'wheels' helps slow the ramp rate so it can be measured somewhat accurately. With normal 1/10 wheels the ramp rate is about 0.1-0.2seconds, with these wheels its 1-1.5seconds, much better. Some zip ties hold the suspension in place so the driveshafts are perfectly straight, minimising vibrations in the drivetrain. Torque is proportional to how quickly the rpm is ramping. Power can be then found by torque multiplied by rpm. Here's the first measurement, a 21.5t Hobbywing motor on a TBLE02S with a half flat NiMH battery:
ntIxv4u.png


Seems to work ok! I have arbitrary units for torque and power since I didn't bother working out the mass/inertia of the wheels, estimating drivetrain losses and so on, but I'm only interested in doing comparative measurements once I put a turbo/boosted ESC in this car so I can work out the best settings.

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fitted lights on the HDT.

HDT lights 3

Camera doesn’t show it but the outer ones are orange, looks better in person.

HDT lights

Need a round file to finish the job nicely.

 HDT lights 2

 

 

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Interesting choice of light location. Certainly looks bright!

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Spent a couple of hours freshening up the RB6.6 for the next race meet this coming Sunday. I've followed a new setup to see if that helps and first impressions are good. It could be that the shocks were so bad , particularly the fronts, so maybe its not the setup its just that anything would be an improvement. I found some tiny stones in the spur gear too, which has chewed up the spur and a brand new pinion in half a battery pack :-( it still runs but is noisy, so a new spur has been ordered.

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Realized that standard wheels and tamiya rally block tires are too tall for the beetle (mf-01x) body to sit properly and not hit the arches on compression. Looks like i have a spare set of wheels for my XV-01 now...lol

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6 hours ago, JennyMo said:

As Michael Caine might say: "Hang on a minute lads, I've got a great idea..."

i-jjN5qzj-XL.jpg

Jx

I assume there will be a build thread? Looks like a great project. Whats the rear end?

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Made a start on the reefer trailer.

I cant beleive how many hardware bags their are plus they are all mixed up so you have have to open all the bags to build it even though they are still lettered like the car kits.

Plus this thing is huge.

IMG_20190404_152345.jpg

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On 4/2/2019 at 12:49 PM, Juggular said:

For most buggies, it will feel like honey-filled differential. (Not that you should put honey in differential. And it's not honey, don't eat it, either...)  

2

Bwahahahaha!

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Shipped out some RM01 hex adapters and axle spacers to a fellow TC member who is thinking about converting his RM01 for a M-chassis shell (similar in idea to my Stratos build).  It makes me happy to see others tinkering with pan car conversions.  :)

IMG_3939.JPG

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12 hours ago, graemevw said:

I assume there will be a build thread? Looks like a great project. Whats the rear end?

Hi graemevw - yes, it just wasn't live yet when I posted in this thread - the link is here:

 

The rear end is a 'Yota' scale axle (RC4WD) with aluminium Axial Wraith lower trailing arms, and custom top links - there are full details in the build thread (particularly as I've since changed the gearbox/transmission components/layout since this original photo was taken)...

Jenny x

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On 4/3/2019 at 2:48 PM, nbTMM said:

Made this crazy contraption:
K7N5QVv.jpg

What we have here is effectively an inertia hub dyno to measure motor power/torque. The wheels act as the flywheels for the dyno, made out of layers of laser cut acrylic bolted together - the first layer has a 12mm hex hole, the second layer has a 4mm hole for the wheel nut and the last two layers are just added mass.

I also added 64 slots to one of the layers so when it is painted black a laser shining through it onto a photodiode can act as an optical wheel speed sensor. I floor the throttle and capture the wheel speed signal on an oscilloscope, which is then analysed by a PC. The added mass of the 'wheels' helps slow the ramp rate so it can be measured somewhat accurately. With normal 1/10 wheels the ramp rate is about 0.1-0.2seconds, with these wheels its 1-1.5seconds, much better. Some zip ties hold the suspension in place so the driveshafts are perfectly straight, minimising vibrations in the drivetrain. Torque is proportional to how quickly the rpm is ramping. Power can be then found by torque multiplied by rpm. Here's the first measurement, a 21.5t Hobbywing motor on a TBLE02S with a half flat NiMH battery:
ntIxv4u.png


Seems to work ok! I have arbitrary units for torque and power since I didn't bother working out the mass/inertia of the wheels, estimating drivetrain losses and so on, but I'm only interested in doing comparative measurements once I put a turbo/boosted ESC in this car so I can work out the best settings.

Simply love it. A former childish hobby becomes science. What are you usually into?

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16 hours ago, Scipunk said:

Realized that standard wheels and tamiya rally block tires are too tall for the beetle (mf-01x) body to sit properly and not hit the arches on compression. Looks like i have a spare set of wheels for my XV-01 now...lol

 You can get around this by putting some O-rings on the shock shafts to limit the stroke a bit.

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2 hours ago, Collin said:

Simply love it. A former childish hobby becomes science. What are you usually into?

I built up a pretty decent electronics 'lab' while studying electrical engineering. I get my fix of electronics at my day job so now I tend to tinker more towards the mechanical side at home - RC cars and building speakers/audio B)

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today i went to the shops and got new wheels after they exploded. if they had just tires, i'd go for it. but they had premounted only. they're not bad, just different...20190404_195614.thumb.jpg.c68c80803b74164a6deba7c8b0b1db9a.jpg

they're vaterras if anyone is curious. has anyone had any experience with them? i'd love to hear how they perform or how long they last.

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My TX/RX came today so I finally finished installing the electronics the cleanest way possible.

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Painted up and weathered my Bearhawk body today. Still needs some MFP and Pursuit decals but I'm pretty chuffed with it. Experimenting with rubbing ink into the car to make it look a bit battered and dirty. 

56681276_569237893486223_289693105862266

56913372_569237946819551_381199748053545

Looks quite at home with my first Blitzer. Although I think I need to have another crack at that sometime as it looks a bit sorry for itself now. 

Cheers

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Finally (almost) painted my YJ body. Now Im just praying that the automotive clear coat I bought will not ruin it :))

B0406469-18CC-4B8C-8E75-262FFB703F4C.jpeg

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Completely stripped and washed a dirty TL01B (Teflon lube. Ball bearings. Diffs got 3Racing ultra-viscosity thing)   

It's been decades since I've done a full-wash rebuild. 

SH457eW.jpg

1/16th shocks are too small to stop the rebound effectively.  But the springs tension are perfect.  While waiting for Mini CVA to arrive, I might experiment with heavier oil.  Hobby King servo, no-name 23t motor installed.  

EqyD4fW.jpg

The arms can do almost 2 inches of articulation.  But Tamiya limited it to half, by giving it short towers.  

Why do you hate full articulation so much, Tamiya?  Why, oh, Why!?

I wonder if cutting a carbon plate would be easy enough?  I have a feeling that plywood towers won't look good.  

 

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Built up my sons new TT01e with a few mods, bearings, motor mount and updated Tamiya prop shaft. 

Here it is next to my over the top (and budget) TT01e Subaru. Both bought cheap as unboxed kits from Tamico.

20190405_200733.thumb.jpg.ad4b655dda82fa4da907fe27a697a902.jpg

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