Monday, May 14, 2018

Another Puddle Duck Update

Is it still spring?  Well, we'll see.

We decided it was time to build my sail.  Sail number one, is being made of lightweight polytarp. 

Here, Dan is helping spread out the tarp so we can mark it for cutting.  


My sail is triagular, 16' tall, 8' deep.  So we cut out the sail blank with around an extra few inches on each side so we could form this thing.  Just as we finished drawing lines, it started to sprinkle.

Polysail, recommends using carpet tape for assembling sails.  And running a line in the seams to take some of the stresses.  Here, we've finished cutting out the sail, and are laying down reinforced carpet tape.  


The tape was placed centered on the line for the shape of the sail.  Then the line is laid down in the tape. 

Since nobody ever takes pictures of me while boat-building, here's some more of dan helping doing the seam forming on the sail.


So.. the whole sail was completed in one night.  I think it took us three hours start to finish.  We could do another in two hours, especially if we  had a nicer place to do sail layout.  Here's hoping it works.

Moving forward, we started fairing the hull as well.  Here all of the edges have been taped.  And we're about to attack the hull with some mostly microbaloon epoxy to hide all the tape ridges and fill the weave of the tape.


The deck and sides were sanded to knock off the biggest epoxy runs, and to reduce the thickness of the needed skim coat.  This.. is about where we decided these boats were no longer going to be 2-3 year boats, and have turned into 5-10 year boats. 

... quality creep.  Going the wrong way.


The shop is unbelievably dirty, and fiberglass dust doesn't make for good bonding. 

It's really hard to take pictures while buttering up the hull.  Epoxy and cameras just don't get along.  If you look closely, you can see the sheen of the wet ballons and epoxy on the hull.  This was after the first batch of the evening.  The skim coating goes really rather fast, so we can do more than one batch a night.


The second batch covered the sides and bow.  As a side note, that's Dan's boat up on the shelf.  It comes down the next week.


Next week?  Next picture?  same difference.  We flipped my hull over, and while I was out, Dan coated most of the bottom of my hull.  We also got his boat down from the top of the pallet racks. 


That night, we started coating some of Dan's hull too.  More updates soon.  

Fixing more bad ESCs. This time it's vregs.

A couple years ago, my buddy and I built some TT02b's.  In those TT02b's we put some 13.5turn motors with these Turnigy 80amp ESCs.  Both my friend an I were having some rather strange behaviors coming from output voltage to the radios.

The BEC voltage on this ESC is provided by a SOT23 package linear LDO regulator of dubious quality.  Enough, that I decided to try swapping it out.  



The ESC is built as a sandwich, and if you separate the case top and bottom, you can access the control board and the high power boards separately.  I used some silicone servo extension wire to run the three pads from the stock vreg, out to a new TO220 package regulator.  The practical benefit being, that TO220 can dissipate a lot more power, and for $0.80 cents or so, the ESC now has 5amps of 5v power.


I still recommend running a glitch buster on your receiver.  Clean power, and decoupling closer to the ground point that matters more, is always better.  But now this ESC can happily power say... a savox servo with no questions and no brownouts.  

Tuesday, April 10, 2018

A survey of car weights.

The following cars are mostly not mine, but for "the record" here are the weights of a few cars.

This is a TRF201, if the stickers didn't say anything.  1635g

This is a TC7.1.  1424g, so it's a bit under weight for VTA.


This is a TT02b MS, with a smattering of upgrade parts.  1568g.  It's got a 13.5 motor in it, and some big pinion.


This is a "heavy" DT02.  Full size servo, battery, etc.  17.5 brushless.  1614g

Here's my cars.... in their proper storage location.  


The F104, is 1106g.  So just barely legal.  I don't have weights on most of the cars up there.

This is my USGT car.  21.5, etc...  FWD so it's got no lower weight limit.  1240g RTR.  That's 110g lighter than the 4wd cars.



Well, it's that time again. TA07s are a thing, and I'm building one.

USGT is the "faster" version of VTA.  The cars are ~10% lighter, they have 20% more power, they have belted tires with sticky compounds, and 2 door modern bodies. 

My friend has a VTA car built, on a TC7.1.  It's a lovely car, does all it should, and being a belt drive goes like it should.  He's heard about my FWD FF03 project, and wants something to run USGT too. 

I swear i'm not a Tamiya guy, but here we are: 



His is a TA07r, so we're going to be able to get a good comparison between the two setups. 

I'm a painfully cheap hobbiest, cruising ebay I found this $30 wonder.


That's a classic Novak 17.5 motor.  What I didn't know, is it's pre-roar rules, so the motor has a permanent sensor cable.  I didn't know they ever did that....  


And it came with the ESC I was looking for.  A Hobbywing Justock ESC. 

I can't resist opening boxes.  I should know already what's in a Tamiya box.  


Exactly as expected.


While we're on the subject of Tamiya.  The TT02b broke it's front shock tower.  My TT02b MS came with a fiberglass one, but they're not really well designed, so tend to break off at the lower shock mount hole.  


I ordered some carbon fiber from a chinese retailer, and the local hackerspace has a tracer mill.  It's setup for a 3:1 scaling, so I made my template 3x normal size.  



I need to check that those upper tower reinforcements won't interfere with shocks.  If they do.. I'll need to make relief cuts.

I hope to have that made soon.  But, as usual, chinese shipping is the limitation.

Tuesday, March 13, 2018

Tamiya TRF201, well, maybe it's a review?

Hey, that's my car wall.  .... What's that strange buggy with pink wheels...



That. That's a TRF201.  But.. why a TRF201?  Well, partially because i'm cheap.  In some bit, because I wanted a better 2wd buggy.  In large measure, because my RC buddy said "i'm buying a TRF201, want in?"

He ordered the cars.  I ordered the motors, escs, and tires.  He also can't leave well enough alone.  Note that box is still sealed, and there's a whole pile of HOP-UP OPTIONS bags.  


The TRF201 has had quite the evolution over the years.  Tamiya "sorted out" the suspension a few years ago, back when the short wheelbase wide sidepod chassis were common.  Those chassis were outdated years ago.  This package comes with the XR long wheelbase chassis.  Not only that, but it also came with the large diameter, shocks. 

You'd expect a kit that came with the "upgrade" parts from the factory, to not come with the stock parts.  ... and this time, you'd be wrong.  There is a complete TRF201 kit, along with a complete XR chassis kit.  The normal shocks for the TRF201, and the large diameter shocks.  Finally, it came with bodies for both chassis.

Remember the "leaving well enough alone" bit?  That pile of parts in front of the box, has the heatsink motor plate, the hard suspension arms, hard accessory parts, the hard wide pod chassis tub, the aluminum bellcrank with servo saver eliminator, and a few other bits and pieces. 

Hobbywing power.  What's there to say?  It's a good brand, has blinky programming, and they have US distributors.  It's hard to argue with that decision.


Most of the build, was in the transmission and rear suspension.  Really, building a buggy, is building a buggy.  No big surprises.  We built our cars with the short wheelbase, hardened tubs.  The local indoor track is carpet, and wanting to be different, but not crazy... well that's what we went with.  Oh, I grew up on the wide side buggies, so that's what "looks right".  


It was a busy night, building the cars.  We spent a good 10 hours, I think.   Between the chassis, and painting the bodies.  We did make a few mistakes though.  Just so you don't make the same mistakes, the temperature you paint your bodies at, MATTERS.  Do it when it's warm. 

However, this is as far as we got in the first night.  Leaving a dark and very cold basement a little to close to lake michigan.....  



We rejoin the story at my dining room table.  So we can install the electronics.  That servo you see on the table. That servo is a mistake.  Lewan Soul 20kg servo.  I mean, it's not "useless" but it's not very fast.  I've seen it used on some cars that see a very hard life, so I think it's durable.  But i'm finding that slow servos make me crazy. 

... I wouldn't buy one for steering.


Some wheels, and .. I swear everything is under that hood.


I also built up the XR chassis.  There are some things to note.  The aluminum standoffs, have tops that match the key shapes on the upper chassis supports.  The chassis itself is remarkably stiff.  And that was true even before the side plates were installed.  It's designed to have tunable flexability, the collection of aluminum standoffs in back are supposed to be tuning parts.  As are the number of screws you put in the side pods.  

Those side pods are another thing worth noting.  You can see swirl marks on them.  They are milled, not molded.  That's probally $50 in milled plastic right there. 

And here we go, the buggy ready to go.  


So... it took me a long time before I really got to drive it.  I took it to an indoor dirt track, and I was not exactly pleased with how things went.  It could have been me.  It could have been the nasty environment.  I was at TimeWarp in Lake In The Hills, IL.  The off road room must have been 105% humidity.  It could have been traction issues too.  Either way, I felt "something" was wrong.

A couple weeks ago, I took the car to Windy City RC, in Arlington Heights IL.  There.. the car felt right.  It loves black carpet. 

I do, definitely, have the shocks setup wrong.  The back end is far to soft, and it could probably use a swaybar to keep all the tires on the ground while cornering. 

More to come, as I get serious about the off road stuff.  

Broken USGT Tamiya FF03 and some VTA cars.

"Racing makes Heroin addiction look like a vague wish for something salty." -- Peter Egan

Crunchy parts are crunchy.  So is driving over your head.

Here's how the day started out, taking notes, charging batteries, and letting tires soak in traction compound.



Look at how far forward that CG is.  Also, the pinions on the table.  To get the speed up on the new track, I needed to go with a 60 tooth pinion.  And even then, the motor doesn't get warm, and I'm still short a little speed on the track.  I have 63 and 66 coming in the mail.


Two races later, things were a little more concerning.  It turns out that trying find time in the sweeper, means you might tag the inside wall.  At full speed. 

Oh how broken you are, let me count the ways.  One, screw stripped out of the bottom of the knuckle.  Two, a shattered hub carrier.  Three, tears in the body.  


I got the parts in the mail to make some charge cables.  Nothing fancy, but $5 in parts, instead of $30 cables.  



I got that fancy body mounted on my TC4.  And we got my friends body on his TC7.1. 




Those are some good looking cars.  We need to find some driver figures.

And a sneak peak at something coming later, a TRF201


Keeping the cars going. Body work and general repair.

Well, this is a catchall post.  Lets start with my trusty DT-02.


Look at that rear wing.  How about those CVA shocks.  Lets fix that.

First off, the wing.  It's seen better days.  It's deeply cracked, and torn.  E6000 and fiberglass and... the thing is good enough for me.



Tamiya branded shocks, are really expensive.  Yeah Racing is a bit less so.  ... A lot less so. 



That's a whole lot of parts.  First lets remove and clean the old shocks.



Something doesn't look right there.  Both the dirt and.. that's a bent tie rod. 



I didn't get any pictures of building the shocks.  But if you look behind the car in this shot...



Hey, swaybars.  Installed.  And the Yeah Racing shocks, with the full soft tamiya springs. 


The Euro Truck needed some work too.  More E6000 and fiberglass.  That repair held up quite well.

So the FF03 wasn't happy with either the stock springs, or even the aftermarket springs.  The damping was waaaay off.  So my first swing at fixing that, was just tweaking the CVA shocks.


From 2 hole, to 3 hole.



Sadly, it wasn't enough.  


So the fix, is a set of Yeah Racing shocks.  Ever since putting the Tamiya metal body shocks on the TT02b, I've been sold on metal body shocks.  I wanted to be serious with my FF03, so going with metal body shocks seems to be the right thing.


I also painted a new body for my TC4.  A Plymouth Barracuda. 






The TT02b got new shoes.  Removing the old tires was... not easy.


If you'd like to copy my tire profiles, here's how I trimmed the inserts.

First, sharp scissors.


Then trimming for width. 



Cutting the corners to help the tire keep its shape.


Here's what the rear inserts look like.


And.. a new set of tires, ready to go.  Oh, hi phillip defranco.


The car was glitching rather badly, the last time I took the car out.  The vreg in the ESC was, for lack of another word, poo.  So I replaced that ESC with one of the "blue 120amp" 


And a heatsink for the motor.

I think it's a pretty slick looking install.