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Mad Ax

Blitzer Storm - Racing Refresh

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This thread charts the conversion of my Blitzer Beetle from bone-stock basher to vintage racer.

The story begins back in late 2011 when I placed an order for a Blitzer Beetle re-release.  I honestly can't remember what shop I ordered it from, if I got it from overseas or a UK-shop or the local shop or even in a trade on here.  Usually there's at least some vague recollection of where and when I ordered things, but this particular model escapes me.  I can't even remember why I ordered it.  I had previously owned a Stadium Thunder, which I bought new-built from someone on here and I ran for a while before selling it on, but I had never really fully 'got' the stadium truck thing.  While it was a lot of fun, and the Thunder body is IMO one of the finest most aggressive-looking trucks to come from the Tamiya stable, I didn't feel the need to keep hold of it.  I sold a fair bit of stuff around that time, so it was probably a victim of one of my random clear-outs.

I do recall that I intended to build this model to mark the end of 2011 and the beginning of 2012.  I had made a plan with some friends for an NYE Build-Off.  My wife (then my girlfriend) and I would head over to our friends' place with a pile of NIB kits and a keg of locally-brewed ale and we would sit and build as the night went on and (hopefully) celebrate the new year with some freshly built Tamiya goodness.  My intended kit was the Blitzer Beetle, I honestly can't remember what my wife had - possibly a TT01 that I wanted built for something, as I'd already built a few and she'd never built a car before.

Alas, it was not to be.  The sudden onset of flu-like symptoms in the destination household put an end to planned festivities, so my wife and I stayed home and watched Star Wars instead, setting a tradition that has become less often our fallback and more often our default state in the NYE celebrations that have followed.

The Blitzer Beetle was not forgotten, however.  It remained NIB until April of 2012, when it was slowly built over a period of lazy evenings and mated to the stadium truck body from a HPI Firestorm.  And the Blitzer Storm was born.

Here it is in all its glory, freshly-built and resting on the sofa in my old flat.  This was back before I bothered to take half-decent pictures of anything.

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A year later the trusty Blitzer Storm accompanied me to a local beauty spot for a light bash.  The wheel fell off.

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And in that sort of condition, the Blitzer would continue as my go-to favourite basher for the next few years.  The shell got a few scrapes and the wheel fell off many more times.  In fact the rear left turned out to be the weak spot on this particular car.  At an Iconic bash at Broxtowe, the rear left stub snapped off completely (I was literally just driving around on track and thought the nut had come off again).  At another even some time later the middle of the wheel came out.  In February last year it rolled over at a Tamiya Junkies bash at Robin Hood Raceway, and when I righted it, the rear left upright split.  It took me until the middle of last year to get a replacement.

Still, it remained my favourite basher right up until the G6-01 usurped it, and after last year's breakage, it lay forgotten in the box on my storage shelf.

In February of 2021 I entered into the Iconic Revival, entering 4 classes in total in the hope that 1 would be successful.  My final option was the Blitzer Beetle in the Truck class, because it would be completely outgunned by more serious race-oriented hardware from Associated and Schumacher, but this year's Revival is heavily oversubscribed and the Blitzer was my only way into the event.  So, instead of tidying up my Super Astute or rebuilding my Buggy Champ, I will be making the Blitzer Beetle ready for racing.

The first thing I wanted to investigate was the shocks.  The Blitzer is mostly stock, apart from an Acto Pink motor, but at some point in its history it acquired a set of 3Racing shocks for a DF03.  These are obviously designed to handle 4wd power up front and for the slightly different geometry of the DF03, because this photo shows how little droop there is in stock trim.  The Blitzer was never the best handling buggy in my fleet but I didn't really care since it was just a basher, but if I'm going to finish anywhere but plum last (and that's a very real possibility anyway) I will have to address this issue.

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This photo shows how much droop is technically possible, although I wouldn't want anything like that much!

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Here the internal spacer has been removed from the left shock.  That's as much droop as these shocks will give me - and probably as much as I'll want.

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Having refitted the shocks for now, I turned my attention to the suspension geometry.  Now I'm not really an expert in setup, but the stock arms are secured with those little step screws and they can back out during the course of a race.  Some cars will cross the finish line with a missing front upper arm (my WR02 has probably done more laps without an arm than with one) but the Blitzer probably isn't one of them, so this little area needed addressing.  I had a DT-03 turnbuckle set lying around for a couple of years, so it got cannibalised for use in the Blitzer Beetle.

Front and rear upper arms are relatively straightforward, although I had to trim yay much off the rod ends to make them fit, as the DT-03 has slightly wider arms.

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One of those little metal top-hat things left over from another kit is a perfect fit in the rear top arm inner mounts so they can be secured with screw and ball nut.

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Et finalement, fitted.

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Steering arms were a different matter.  The Blitzer has an off-centre servo mount and retrofitting of parts from other cars isn't really allowed - although bell crank steering was common on RCs by the time the Blitzer was around, to do a job in keeping with the spirit of the rules would take longer than I had on a spare Sunday - watch this space for a possible alternative later in the year...  The DT03 has a central servo mount, so the provided steering turnbuckles don't fit.  I managed to use one of the supplied turnbuckles on the left-hand side with some shorter open-cup rod ends, and in the right I found a spare turnbuckle that had come from something completely different, with a US thread size on it.  That was fitted with the closed-cup rod ends.

A week passed before I had time to look at the Blitzer again.  (If I'm being honest, it wasn't time, it was weather.  It turned cold again last week so the workshop was just too dark and chilly to go poking around in of an evening).

When I returned to it, I decided the shocks needed attention.  The front was way too stiff, even with the rock-solid springs that come with the DF-03 kit.  Now maybe hard springs are all well and good on a DF-03 with its longitudinal-mounted battery and its front gearbox and its extra traction up front, but I doubt it would help my campaign in the tail-heavy Blitzer.  Even with those big wheels, I'll need all the grip I can get up front.  I found a set of Yeah Racing red springs which fitted well enough and have a more progressive feel (I really should get some kind of spring gauge so I can tell for sure).  I did a mount-and-bounce first without oil to check for sag.  There was a little - and that's a little more than I had with the 3Racing springs.  I instinctively feel that I need to go softer still, but unless there's some kind of miracle and I get a day at a Tamiya Junkies Meet in the early summer, I won't have a chance to race this truck on astro until I hit Bingham Model Raceway for the Revival - and once I hit a proper modern astro track I might decide I want that stiffness after all.  Suspension isn't doing much if the nose is bouncing into the track surface over every bump!

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I went with Tamiya red oil to compliment the springs.  The shocks only have 2-hole pistons fitted, perhaps they need less but it was a lot of hassle to change them so I just went with softer oil.  I quick blast on the tarmac outside the workshop didn't really tell me much other than that it's still understeery as heck.

Next I added some weight up front.  Again, driving around at home I don't really get much of a feel for it, but on astro (and with race tyres fitted) this little beast is going to wheelie like crazy.  Again, wheelying looks cool, but you don't win races if your front wheels aren't on the ground.  Fortunately the Blitzer chassis has a nice ribbed section which is the perfect size for some tyre weights.

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Having partially sorted the suspension, I turned my attention to the electrics.  The Acto Pink is absolute dynamite in this truck, although I will have to watch the motor temps on track and take an alternative just in case it's getting too hot.  However as the photo in the last post shows, the motor leads aren't long enough so the ESC is perched awkwardly on top of the battery retainer.  My next job was to fit some new leads with proper gold plugs.

I'm fairly useless at soldering and I usually end up melting something, so I figured my best bet was to strip down the motor.  In the process I discovered one of the resistors is broken, but it hasn't affected operation at all.  I guess there is a reason for them.  The colours are badly faded and no matter how I try to brain it out, I can't get a sensible figure from the bands so I have no idea what to replace them with...

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With new wires added, I was able to relocate the ESC and radio further forward and under the tray.  They should be better protected there in case it rains again (especially the radio, which makes no pretence at being waterproof).

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Next up, now that the overall weight distribution is more or less fixed, it was time for suspension adjustments.  I don't have a setup deck for buggies but these camber gauges are from a Hudy car setup station and they work OK on the rear.

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I have to be a bit more creative up-front and push the flats against the tyres.  Hopefully the tyres aren't too far out of round.  Tamiya tyres are fairly hard so they should be OK.

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Then it was time for a new servo.  I had an old Futaba S3003 fitted, but it felt horribly slow when test-running on the tarmac.  Lock-to-lock could be measured in pandemics.  Initially I grabbed an Alturn AAS-752MG high speed servo from my spares box but it seemed to be much faster one way than the other, so I aborted and took a new Savox 0254MG from the Super Hotshot box.  These are a budget servo but very well made (being Savox) and on paper the Alturn is faster, but in my experience and in real world conditions the Savox gives better performance, and the price is near identical.  So in it went.

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I wish I'd tested the servo before fitting, as it still felt a bit sluggish when I was driving around the lane.  It may be that my Tx needs a reset - I once had an issue with my Spektrum DS-3C and my WR-02 whereby the steering servo was incredibly slow and had very limited motion in one direction.  Flipping the reverse option reversed the problem.  Different servos made no difference.  All the EPs / trims / subtrims / expos were neutral but still it refused to work.  Eventually I did a Reset on that particular model memory and suddenly it was all fine.  I know this model has been re-bound a few times so perhaps it's got itself confused all over again.

After that, and before tuning the steering angles, I decided to resolve the Blitzer's inherent bump steer problem.  You can see here how different the steering link angle is to the suspension arm angle.  Ideally they should be the same.

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By swapping the hubs from left to right and mounting the balls underneath, a near-perfect angle is achieved.  Unfortunately the cups catch on the suspension arms, so some modification is required.

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On the right side, which uses long closed cups, I had to grind the end off the outer hinge pin

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Then trim away some arm with a scalpel

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Angles are now much, much better and bump steer is almost eliminated.

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After that I had a more proper test-run on the tarmac.  It's still very understeery, but the lane is very tight and completely the wrong surface for the tyres (I'm not sure there's a right surface for those tyres).

I also had problems with gearbox noise, and motor noise, so I ended stripping both down for a proper clean and reassembly.  The rear diff was originally built with (quite a lot of) Blu Tack for a very stiff operation, but over the years it's squoze out into the splines.  Also for a while it was run with a Tamiya cheese pinion, so the spur was covered in silver soap.  With a decent clean and some oil in the bearings it was reassembled and is now much quieter.  I think I'd put the motor back together with the brushes in the opposite side, which created a bit of noise as they re-bedded.  A little bit of oil on the comm to help them bed in and they soon quietened down.  The brushes are about half way through their life and the comm isn't in great shape, so I probably need to get new brushes and have the comm serviced before a special motor ends up unusable.

So - what next for this project?  Well, I need to get some decent rubber before race day, and as the truck is so nicely colour-coded I think I need another set of orange Blitzer Beetle rims to mount them on.  I may also buy some more springs as I don't really have much choice for buggies, but I'll see how the cash works out between now and race day.  I very much doubt I'll get the car onto astro before Revival, so running will be limited to a little bit of garden bashing between now and then.

Spares-wise, I'll be taking my Bear Hawk along, although it is vintage so many of the plastics could be brittle.  I may possibly buy and assemble a spare transmission - it's a fairly quick swap on the Blitzer, and the Bear Hawk ratios are different.  I'm slightly considering making an FRP chassis, but it probably won't offer any performance advantage.

I won't say "watch this space" because I'm not sure when the next update to this thread will be :)

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Nice story telling as usual @Mad Ax

Sounds like some of the setup i used on my DT03 truck. I am running tamiya trf501 red front springs on that at RHR which are about 3.2lb. Core RC CR180 is 3.1lb. I have run the really soft kit springs before for grip though. I am running DF03 gold rear. 

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The stars aligned on Friday.  I had to make a special trip into central Bristol for work (to pick up some equipment for my new home office).  Since we're still in lockdown in England and under a Stay At Home order, this was like a little holiday.  Plus I was able to do it during work hours because it was work related.

The extra bonus is that it's just as quick to go through central Bath to get to Bristol as it is to go around the outskirts, and that meant I was passing right by the door of Racecraft RC.  The super extra double bonus was that Racecraft RC had a set of Schumacher tyres and foams and Blitzer Beetle wheels in stock, and because I was able to order online before I left home, it was legal to stop and collect them on the way through.  Also we are now permitted to have a conversation with another human being on a park bench, unfortunately I didn't have a park bench to take with me so we had to stand up, but we were able to stand outside and have a quick catch-up and do some breeze-shooting, which was quite refreshing after nearly 3 months of basically talking to my wife and child.  I do love my family, honest, but, well, sometimes...

Anyway, I came home with quite a haul - Schumacher Vee2s in yellow for the rear, yellow staggers for the front, two pairs of soft foams and Blitzer Beetle wheels to match my paint scheme.  When you drive as badly as I do, you at least have to look good while doing it.

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My plan had been to get the tyres fitted to the wheels first thing this morning, but I pulled my tyre glue from the drawer and discovered it's turned into jelly, so that will have to wait.  An order will be going in for more glue (and a whole bunch of other stuff) over the next day or two.

Also I had arranged a swap with @ThunderDragonCy for his DT02 steering turnbuckles for my DT03 steering turnbuckles, so now my truck has proper Tamiya turnbuckles up front.  I had to cut the closed cup ends down like I did with the other 03 turnbuckles but otherwise they were a perfect fit.

Shiny new Tamiya buckle on top, skanky old random weird thread turnbuckle middle, shorter Tamiya turnbuckle on bottom

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This project has been waiting for me to get a bit of spare time, but with the Tamiya Junkies meet just around the corner - probably my only chance to run the Blitzer on astro before the Revival - I figured it was time to stop being lazy and get it sorted.

First thing I needed to do was check the pinions.  I popped the motor out earlier in the week to discover I was still using an OEM cheese pinion - a lot of my older runners suffer from this problem, as a) I didn't understand that Tamiya pinions weren't good and 2) once I did understand that, it was too hard to find reliable information on the actual pinion pitch, and then iii) it was too hard to find a supplier of a pinion of the correct pitch, correct number of teeth and in a material that won't turn to paste in a couple of years.

Of course things are different now - a Google search brings up plenty of thread (mostly on Tamiyaclub) and Modelsport have a very good stock of pinions, searchable by pitch and number of teeth.  I usually use RW steel pinions but Maverick also make them in brass, which is better than Tamiya's alloy but softer on vintage gears.

For reference - the correct pinions for the Blitzer Beetle (and other stadium trucks with the same gearbox) are 13T and 15T is Mod 0.8, and you don't have to "make do" with a 32dp any more because there are plenty of Mod 0.8s out there.

Here's the Blitzer chassis with the Acto Pink out pending a pinion change, plus a parts haul in the background from Modelsport.

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I had a bit of hassle with the pinions not meshing properly, and in fact I feared I'd got the wrong pinions altogether because everything was too tight once fitted, but then I realised I was using the wrong holes :faceplam: 

After sorting that, I turned my attention to the rear hubs.  I've broken a few of these in my time, in fact the Blitzer was out of action for most of last year because I couldn't get new ones.  Then @ThunderDragonCy came up with this neat little option part:

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3 degree toe-in rear hubs!  Also with adjustable top mount.

Fitted:

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Stock on the right side (bottom), new on the left.  The lens is distorting the angles at this distance so both sides look like they have massive toe-in :o 

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After that, it was time to fit the tyres.  This is one of those jobs I really hate.  I bought some Core RC tyre glue a few weeks back and it's thinner than a size 0 model.  It seems to want to go everywhere besides the bead on the rim.  It's so thin it will capillary up the nozzle when it's still 45 degrees from horizontal then gather around the neck, so that it runs onto the outside of the rim as soon as it's within jumping distance.

Anyway, enough moaning about it - here's the haul of tyres I got a few weeks ago from Racecraft R/C.  I still need to save up for wet tyres, because, y'know, Revival :o 

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I made such a mess doing tyre #1 that I figured it would be easier to trim the wide shoulder off the nozzle so I could get it into the bead without touching the outer rim.  I used a pencil sharpener

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Tyres glued and drying - now I can mark this item as complete on my CarManager app:

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As always, your Storytelling is far superior to anything I can do!  But your modification skills are really on point!!! 👍👍💯

I REALLY like your Bumpsteer Mod - although not more than flipping Steering Arms and some grinding... Was brilliant! Simple solutions often are. Good Tyre Glue is often a MESSY deal. 😖  If I could offer one of my UNCONVENTIONAL solutions to this sloppy problem... spacer.png

If you could get hold of some Syringes, I believe that you'll find no better option for applying Tyre Glue!! I've used Syringes on all types of Tyres lately, and not gotten a DROP anywhere, except where I wanted it! 😉👍

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@Carmine A oddly enough, as I was doing the job, I thought to myself what I really need is a fine syringe!

General purpose syringes aren't too hard to get hold of from craft suppliers etc but not sure if I can get anything with a hypodermic needle - actually I'm pretty sure there's a service that gives free hypodermics to addicts to reduce the problem of sharing needles, but I'm not sure what hoops I'd have to jump through to qualify :o 

Going into a pharmacy and asking if they can sell me a pack of hypodermics might be met with some interrogative questions ("I use them for gluing tyres onto toy racing car wheels" might not suffice).

Actually the whole thing would be easier if the glue pot came with a fine needle on top, like some plastic cement glues do.  It doesn't need to have a sharp point, it just needs to be long and fine.  Maybe there's a syringe on the market like that already for hobby or engineering applications...

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@Mad Ax I would assume that a Pharmacist COULD think unsavory thoughts! You could maybe print the picture I just posted, and show them that... It MAY make a difference. It COULD! 😋

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Very nice thread! Thanks for sharing your story!

I stopped using crazy glue on rims for vintage cars. I prefer Pattex glue. Not as strong, but will keep the rubber in its place. And later it is removeable without oven or damage to the rim. I use it for the Dyna Storm. It is a thicker fluid that will dry out as a kind of rubber, so I first treat the bead entirely before seating in the tire. Nice and clean ^_^

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I got the Blitzer back on track again this weekend for another shakedown before Revival.  With the new tyres fitted properly and the body trimmed for clearance, it's a much more driveable beast.

The first problem I had came within minutes of putting the car on the astro - I was still doing my initial steering trim setup when the front shock came off.  It seems Tamiya give us a tiny little bit of thread to use for these shocks.  I plan to remove the arms, drill out the recess and fit longer screws, or possible even recess in a nut so I can use a machine screw.  There's few things more annoying than failing to finish a race because a self tapper backed out.  Well, actually, that's a lie - mouth ulcers are more annoying, people who camp in a camper van on a busy campsite without knowing who to disable their anti-theft alarm are more annoying, failing to finish a race because you just obliterated the entire back-end of your new car on a poorly-assembled track barrier literally 30 minutes after you obliterated the entire back-end of your old car on the same poorly-assembled track barrier is more annoying, but even so, I think the point is well made.

The car went well but I had to stop and fit the smaller pinion after the Acto Pink stopped working with a sticky brush.  These were all new brushes not long ago so the heat obviously didn't do it any favours.  Later that day the car stopped again, so sadly I think it's time to swap out the Acto Pink for something newer and more reliable, at least for racing.

My home-brew body posts aren't very good.  They never were.  One roll over and they move.  I need to come up with a better option.

Also once again I'm seeing a lot of wobble in the rear wheels.  I've continually replaced the rear axle parts on this car - several wheels, a drive stub and an upright.  I think the parts can't really handle the big wheels.  I'll get some spare drive stubs just in case.

Otherwise, it was good to drive.  It bounces a lot, perhaps needs the shocks rebuilding, and it did have some grip roll once I got my confidence up.  I took some camber out of the front to reduce the initial bite, which seemed to help a bit.  I think I just need to get to Revival now, stop tinkering and start racing!

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On 6/27/2021 at 7:42 PM, Mad Ax said:

Also once again I'm seeing a lot of wobble in the rear wheels.  I've continually replaced the rear axle parts on this car - several wheels, a drive stub and an upright.  I think the parts can't really handle the big wheels.  I'll get some spare drive stubs just in case.

A little late for this I know, and I'm not sure if it's allowed (but since you used DT02 turnbuckles, maybe you could get away with this):

TT02B/DF03 universals in the rear should help eliminate the drive stub issue, by eliminating the drive stub entirely. That's what I have fitted on mine.

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Another quick update on my Revival prep!

The screw pins that hold the suspension arms into these cars are notoriously unreliable, and tend to come out over time.  The more it happens, the worse it gets.  My Bear Hawk can barely last a full race distance without losing a pin.  Also they're mild steel, so if they get wet (or particularly, if they get salty during beach running) they can corrode, swelling up inside the arm and seizing the suspension.  I've had M03s that have needed to be put in the bench vice to have the screws tapped out with a punch.

I had a couple of sets of TL01 stainless pins, so I thought I'd see how well they fit.

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Front inner pins fit perfectly

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Front outer pins have a bit of overhang.  I added a rubber grommet from a servo to keep this one pulled forwards.  Using the Bumpsteer Mod (aka flipping the knuckles upside down) puts the steering rod end close to the pin, which could bind the steering, so keeping the pin pulled forwards was beneficial here.

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Rear inner pins fit nicely

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The rear outers wouldn't fit - they're too wide for the smaller pins and there weren't any longer pins spare.  However I did open a second set of pins for another car last week and have some spare, so I might be able to make those fit.

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The other problem I was having was with my body posts.  This is a solution I came up with when I first built the truck around a decade ago.  The body posts are from some Tamiya parts tree, with the bottoms cut off and a recess cut into them so they slot over the webbing on the shock tower.  It was never a perfect solution and over the years they have got progressively floppier.  If the truck rolls or gets hit on track (which is inevitable) the body could bind up on the wheels and stop me racing, and as it's a non-standard installation a marshal might not be able to fix it.

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To finish first, first you have to finish.  I have absolutely no expectation of coming first, but I would at least like to finish my final, so I need to resolve this problem.

This is a plate cut from 2mm FR4 sheet.

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This is the plate screwed to the body posts.  It adds some rigidity in a sidewaysly direction so the posts can't flop over.  Potentially it could expose a weak point in the posts around the screw point, but I'll take some spare posts with me just in case.

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I was also having problems with my Acto Pink cutting out last time I ran the Blitzer.  It's been in there for years and never given me any trouble, but the brushes weren't in great shape so they got renewed a couple of months ago.  However the problem reappeared last time out, so it was time to look closer.

I have been fitting these gold plugs to all my cars, thinking that a) they would be more reliable than the Tamiya bullets and 2) they would make it easier to swap motors around if everything has the same plug on, but during Round 1 of the Iconic Cup back in May, both my cars were cutting out constantly and these plugs turned out to be the culprit.  I think the spinny gold spring bit doesn't properly contact the inner pluge very well and overheats when in use.

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The solution, which I forgot to photograph, is to get some flux down into the pluge and then put a bit of solder in it.  In theory that should make a perfect electrical contact and providing there isn't too much solder, the spring should retain some springiness.  It worked well enough on my Cup cars last time out, with no motor cut-outs at all (although my FF01 did suffer a couple of brown outs on the straight, when all radio power was lost entirely, which the cheap ORX receivers I use are famous for.  Bigger capacitor added for the next race seemed to fix it).

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After that, I turned my attention to the front bumper skid.  Historically, I wouldn't put bumpers on my runners because I'd typically bash alone or with a small group of friends in an open space.  A bumper served no useful purpose and made the truck look ugly.  For a long time the Blitzer had no bumper at all and the Bear Hawk had an alloy Radshape bumper designed for a Grasshopper, because it looked cool.  However it was only held on with one screw and was therefore likely to break the front bulkhead in a crash.

When I raced the Bear Hawk a few years back, I took the alloy bumper off and fitted the best one I had, which was the unused one from the Blitzer Beetle tree.  After a bit of racing, the front bumper no longer looks so new.

That meant I had to fit the tatty old Bear Hawk bumper to the Blitzer Beetle, and after a practice day at RHR it's got a split underneath.  This is a problem on a race car because it could dig into the astro on a nose-heavy landing and flip it over.

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My possible fix involves an old Tamiya parts tree, pair of snips and a gas-powered soldering iron with a medieval torture implement on the end.

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With the appropriate application of heat, the broken plastic is melted and new plastic is let in to seal the gap.

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There's no guarantees this will be a permanent fix - it might be just as bad or worse after Friday's practice sessions, but it's better than throwing it in the bin.  I'll have my Bear Hawk as a temporary parts donor, so if it fails I'll have a spare.

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And that's just about it.  The Acto Pink gets hot on track even with the smallest pinion, so I fitted a heatsink and cooling fan, but for some reason the fan won't turn when powered off the radio.  Just in case there are motor problems on the day, I also soldered long cables on to an Etronix 17 turn sport tuned motor, so I can swap that in if I need to.  This is me pretending to be prepared :)

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UPDATES!  It's been an age since I did anything with this truck, but 2025 is a new direction for my vintage racing, so it's getting a serious conversion.  Most notably, it will be converted back to buggy spec for some racing action.

SO, what's this all about?  Well, last year I bought a Schumacher Cougar to give me another class option to race at Revival 2024, without realising it's in the same class at the Super Astute, which I already have.  I was accepted into the Cougar / Astute class in this year's Revival, but the Cougar didn't go all that well in my hands.  Not that it's a bad buggy - it's very capable, and it was an inspiring build - I just didn't gel with it, and wasn't able to put in any good laps all weekend.

I much preferred driving my custom-chassis Hotshot on 4wd day, and when I did well I could feel proud that a car I'd make myself was beating cars that Tamiya designed, and when I was doing poorly, I could accept that I was driving a car I made myself, and not something bought from a shop and thrown a load of performance parts at.

So, finally, I decided it was time to do something I've been thinking about for ages - build a custom Bear Hawk!

A Bear Hawk, you say?  But this is a Blitzer Beetle, right?  Well, yes, and no.  Apart from some different colour parts and some body mounts, the chassis are virtually identical.  In fact the only main difference is the gear ratio, which (I believe but have not confirmed by checking the manual) is slightly lower on the Blitzer Beetle to account for the bigger tyres.  Although stadium truck tyres are basically 2.2 rims with a little sliver of rubber around them, which is about the same as a modern buggy tyre, only wider.  Which means that, on track and wearing modern tyres, the Blitzer Beetle gearing is more appropriate than the Bear Hawk gearing.

So...  let's crack on with this build!

This is how I pulled it out of the box.  I can't remember if this truck has been run at all since Revival 2021.  It's probable that I've taken it to Tamiya Junkies at some point, but I don't really recall.

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This is how it looks under the body.  Mostly clean, almost stock.

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I stripped it down to the tub.  I'll use this as a template to build my new chassis plate.

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This is some FR4 sheet, 2mm thick.  I went for 2mm because 3mm seems like overkill, plus I'll have to use a top deck to brace the front and rear bulkheads, as they were never designed to fit to a plate chassis.  I could have gone for black (it would look more stealth) but natural yellow has somehow got a more authentic early 90s feel to it, plus I couldn't get hold of any black in 2mm thickness.

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At first I meant to use the front edge of the chassis as the origin for marking my screw holes, but it felt like there wasn't much meat in the FR4.  I don't want it to crack on track (oddly the Bear Hawk chassis is famous for cracking here too) so I spaced it out with a convenient true straight edge.

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Convenient true straight edge

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In order to accurately mark the holes, I'll need to drill through from the top.  However the holes in the chassis are blind, so I drilled them through first with a 2mm bit.  A 2.5mm bit would give me a more accurate mark, but then I'd ruin the stock chassis, and I want to keep it in case I ever want to restore the car to standard again.

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Here is how we mark our holes.

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First hole drilled.

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Second hole marked and drilled.  However here the slight inaccuracy in my measuring technique shows - the second hole is very slightly closer to the leading edge than the first hole.  This doesn't have to be a huge problem, but it now means the straight edge along the far side of the sheet is no longer true to the centreline of the chassis, and therefore can't be used as a datum.

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At least it all fits.  I don't always manage to drill my holes in the right place (even after marking and pre-drilling them with a smaller drill) and sometimes they are out by a whole millimetre, and don't fit at all.

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Now I can drill down through the rear of the chassis to mark the holes that will mount the transmission and rear bulkhead.

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With all holes drilled, we now have a solid base from which to mount our bulkheads.

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the oversized chassis plate was causing problems, so I cut it down.  I had to use a variety of inappropriate hand tools for this, hence the wavy line.  Doesn't matter, this isn't the finished dimension for the chassis.

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I also figured I would need to add a new datum that I could rely on.  Measuring by hand doesn't come easy to me, but I marked the centre between the two holes at each end, then joined them up to get a true centreline (or, as true as it's ever going to be).

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Then I marked where the rearmost screw hole for the transmission case should do, using the stock skid plate and a little bit of guesswork.

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I wanted to assemble the chassis to see how it looked, but I'd intentionally left too much overhang on the front end, so I had to tidy it up.  I made two sets of cut lines because the first set looked too close to the screw holes.

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There we go.  Not the final shape, but should allow the front end to be assembled.

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And there it is.  Kind of looks like one of those hideous Yokomo 870c things.

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