Some custom modifications on the King Blackfoot
On a Monster Beetle, there are 3 main weak points:
- the gearbox
- the front damper tower
- the lateral body mounts
The two firsts points were redesigned on the different Blackfoot generations and should not be a problem anymore on the King Blackfoot. The third is no longer a problem either... unless you used the original Monster Beetle body mounts as I do. It is a good idea to reinforce them, even more as my King Blackfoot will be seriously driven: its motor is a Kyosho Mega Motor de 22 tours (yes, the pink one!).
The Monster Beetle rear body mounts weakness is a twin problem: where the body mounts are screwed onto the chassis on one hand, and the mounts themselves on the other. Efforts on the bodyshell (rollover for example) go onto the mounts pressing them inward the chassis and the movement spreads to reach the chassis.
The solution solution is to secure the space between the two chassis mounts and the two body mounts. It is easy to make: it is the same built you can find on many Lunch Box to reinforce the chassis.
The required parts are the same for both stiffeners, the only difference being the length of the aluminum tube:
- 4 3x40mm screws
- 4 flanged tubes
- aluminum tube ø 5mm: 48mm and 78mm long
- 1 damper base
The ø 5mm aluminum tube (external diameter) can be found in any RC plane shop as it is used for wing structures on planes.
Cut the aluminum tube with a saw. I recommend you cut them a little longer that required. Sand paper will help you adjust precisely to the correct length and get a perfect finish.
Then insert the flanged tubes at each aluminum end: they are important. First, they protect the plastic parts the tubes press on. Second, they reduce the inner tube diameter. The screw used are 3mm diameter when the inner tube diameter is 4mm.
On the longest tube, insert the damper base. You'll have to widen the hole to pass the tube through it. Just drill into it with a 5mm bit. Place the damper base right in the middle of the tube.
The next step is to place each tube and to screw the 3x40mm screws. The screw length gives more rigidity to the aluminum tube. You can use a threaded rod instead, but you won't gain any rigidity: if the aluminum tube should bend, this would mean the force onto the chassis would break everything else.
Here is the complete install of the two stiffeners onto the chassis:
The damper base used on the upper aluminum tube lets you add another fix onto the rear damper tower to limit any move of the body mounts. It is a basic fix but it does the job: an epoxy plate, a 3x15mm screw and a nut. The type 850 bronze metal bearing (recycling again) and the little pipe are used to fill space between parts.
The upper stiffener leaves room for a outward movement. You can eliminate it using the original Monster Beetle G1 plastic part. But as it was generally the first part to break on the original chassis, I think it is useless to install it. The remaining movement is very limited though: but if needed, I will try to make an additional stiffener for it.
New bodyshell: King Blackfoot
My Monster Beetle #2 bodyshell was not exactly in perfect condition when I placed it on this chassis. After a few runs, the SuperStock BZ muscles had turned it into some kind of convertible (might be the failed jump landings though ). Ideally, I would have liked to find the original bodyshell but it is no longer available (unlike the sticker sheet in some european stores). With the Blackfoot III release, the Super Blackfoot bodyshell became available: this is an interesting "vintage" alternative as long as you don't use its modern sticker sheet. At the time when I was looking for a bodyshell, the Blackfoot III wasn't yet announced, only the Blackfoot Xtreme's was available.
9335402 Blackfoot Xtreme bodyshell
9495268 King Blackfoot stickers
Warning: the bodyshell does not come complete. You need to get these extra references:
- 9115142 - J tree (chromed bumpers)
- 0115228 - L tree (windscreen / headlights)
- 9005734 - G tree (roll bar)
- 9400078 - C tree (screws)
With all these parts, you can transform a Blackfoot Xtreme bodyshell into a King Blackfoot's. I want to point out this is a visual effect, not an exact replica since there is a major difference between the two bodyshells: the air intake on the front bonnet.
Despite this, at the cost of cutting the bonnet sticker, the result is pretty OK:
Additional information: you will need to re-drill the bodyshell since the body mounts are located differently. For this, First start at the front of the bodyshell: the places were to drill were refilled and are still visible. Visually, look for round chips located inside the bodyshell. At the rear, the new holes location is not visible: after placing the bodyshell in its new front body mounts, you will need to look where the body mounts touch the body shell to mark the place where to drill the new holes. Warning: do not trust the refilled places you can see since they are 65mm wide when the King Blackfoot body mounts are 60mm wide.
The snow finally came out, so this was a nice time to run the King Blackfoot.
For the driving part, racing line precision and handling, weather conditions could not lead to any kind of analysis
Nevermind, for the driving fun, no problem at all: the King Blackfoot is great. The suspension does its job perfectly, smoothly but never leaving the chassis bump the ground. The motor didn't seem in great shape as the power it delivered was somewhat weak for a 22 turns: I bet the T2M Speedster Jr speedo (even rated 19 turns) is guilty for that as it made frequent micro-cuts. Anyway, I planned to replace it by a better one.
The general handling is very good, except for jumps because the King Blackfoot always lands on the rear wheels. Despite of the dampers action, it will always have one of these reactions: rear bouncing and flip to the front wheels or completely flip rear-way. Depending on speed, it always makes a salto, either front-way or rear-way. That's a good way of testing how solid the body mounts are: no problem. Either landing on its roof and getting back on its wheels, or just lying on its roof like a turtle on its back, the body mounts kept solid. And you can bet that I'm not proud at all of some jump landings
Some photos while my hands could still operate the camera in the cold.
Update 03/03/09: the King Blackfoot is great! An afternoon driving on a rough terrain and the suspension works like a charm. An afternoon also dedicated to dominate the beast power that makes it handle like a Lunch Box each time you start full throttle. And of course, it was time to take some air...
Bonus: the King Blackfoot promotional video when it was released back in 1997 (© Tamiya)