New project: Kyosho Blue Streak Resto

[Kmot]

In return for giving a fellow Irregular a couple Johnson Mini-EV motors, I was given a Kyosho Blue Streak. It is complete except for radio gear. It was a bit crusty, sitting around for who knows how long.

The inner hatch cover had a section cut out of it. No idea why. The top hatch, where it is secured by a hitch pin, had been poked so many times with the point of the pin it was almost a big hole there.

It was dirty inside, and stained and dirty outside as well.

The stock motor was there, and it was a typical lo-po can motor. But it comes with a gear reduction.

Okay, so first thing was to remove the motor and gearbox. I disassembled the gearbox and was happy to see it had ball bearings in it and they were in good shape. I added some fresh lube to the gears and shafts and reassembled it. I hooked up a Speed Gems 2 "Amethyst" 10 turn motor. This motor has already been prepped with water cooled brushes and a cooling coil around the can.

Next was to thoroughly blow out the insides, then wipe it down with rubbing alcohol to remove the old grease and other stains and dirt. Then I scrubbed the outside with a sponge and dishwashing soap.

Once the hull was dry, I removed the prop shaft and cleaned it of the coagulated grease. I applied fresh Prather cable grease to the prop shaft and did the same to the outdrive shaft. I replaced the rusted Phillips screws on the outdrive with stainless steel socket screws. Then I reassembled the motor and gearbox into the boat.

Next, I installed a new servo and connected it to the outdrive steering and adjusted the neutral point.

The next project was to cut and fit pieces of ABS plastic to patch the area where the hitch pin goes and to close the 2"x1" area that had been cut out of the hatch. I used scrap ABS from my Graupner Neptune containers kit and welded the pieces in place with Plastruct liquid cement.

Once the boat was this far, I placed a receiver, esc, and battery in the boat to see how it sits in the water. It looks pretty good. It will be interesting to see how this boat performs.

[MILLERTIME]

Looks good Kmot

[Kmot]

Thanks Don. As for how it looks, all I did was give it a bath. :p

[MILLERTIME]

Maby a bath will make me look better?
I'll have to give that a try.
Thanks
Tom

[Kmot]

Well, it is Saturday night after all. :D

[waboats]

Word of warning...

Don't use a micro switch or Tamiy Connectors.. ;) Member what can happen... Bring the Video... :p

She's a big boat for 6 or 7 cells and does need about 10-12 to get going at speed.. OK at 6 but not that slick. The stock motor cooks on 10 cells so might need a hop up (no lower than 19 turns)..

Got this from a mate who raced these as a one desing cloass for a few years..

Good luck with the project..

Cheers

John

[Kmot]

John, the very first thing I do after testing a brand new component to be sure it works, is snip off those miserable Tamiya connectors.

I have installed a 10 turn motor. I know from experience with car racing that I can run 8 cells. Since this is also on a gearbox, I reckon it will be safe on 8 cells. And, a 10 turn motor on a smaller prop (which I have already installed) should give it far better than stock performance. If it sucks, I am prepared to go up to a MUCH larger motor and cell count if necessary. But the hull is very thin ABS and would not hold up to the pounding the extra weight and speed would give, I am afraid.

Thanks! :)

[waboats]

Kmot

Too True

Sorry missed you said it had a Gearbox... Been late & distracted...

Cheers & Good Luck... They are a good fun boat..

John

[Kmot]

I tested the Blue Streak in the pool today. This boat is going to be a real challenge to get dialed in. I initially tried a 37mm prop (stock is 42mm) because of the lower turn, higher revving motor I installed. It mostly cavitated. I tried a larger prop, a 42mm. It cavitated. The strut angle is adjustable. I tried it all the way up, and all the way down, and a couple spots in-between. It cavitated. I reinstalled the 37mm prop and tried different strut angles. It cavitated. I then installed a 45mm prop and with the strut all the way down it started to act like it might get up on plane. Took half the length of my pool (40') to sort of get some speed going.

It is confusing. The boat came stock with a very low performance 550 motor and 42mm prop. I installed a very hot 10 turn 540 motor. Should need a smaller prop. But it would not give any indication it wanted to get on plane until I installed the largest prop in my box, the 45mm. It looks like a 47mm would be max size before it hits the anti-cavitation plate. I'm not sure what to do. I might try changing the CG of the boat by moving the battery up forward.

With the 37mm prop it pulled 63 amps on a 7-cell pack. With the 45mm prop it pulled 70 amps. The esc is rated for 50 amps. Must be a good esc! :p

[Kmot]

This boat is a real bear! I am beginning to understand why it is out of production. :p

I finally got it dialed in. It was hooking up good and actually had decent speed. I have searched on the internet about this boat and found a couple users pages that indicate this boat had a speed of about 5 k/ph in stock form. I would estimate mine was doing aroun 12-15 mph today. This was on 7-cells and a Kyosho 42mm prop.

Only problem was, the 10 turn motor, even on a gearbox, got too hot. :p

Back to the drawing board........... :rolleyes:

[Kmot]

Making progress. I grabbed the nearest motor. It was a Fully motor from the Midwest PT boat.

Trying different props again and different strut angles I have found a sweet spot. The major thing is still the CG and moving the battery forward. But now that that has been done, the boat is reacting to prop and strut changes. Kyosho really goofed when they placed the battery holder where they did.

The Fully motor pulled a whopping 19 amps on a 45mm prop. :p

But that particular prop (Hobby Lobby) is garbage and has never worked worth a hoot in any of several boats I have tried it on. Next was a 42mm Graupner K series prop and the boat responded well. On 8 cells it pulled 25 amps. But 8 big 3300 NiMh cells is too much weight. I will concentrate on 6-cell and 7-cell battery packs and different props and strut angles but I think I am very close. This Fully motor is lower performance than the 10 turn obviously. But better than the lowly "stock can" motors that come with Kyosho and Tamiya kits. I think actually this boat might kick some butt with a Graupner Speed 600 and the right prop and strut angle. Hmmm..... I have a Speed 600 in my Stampede truck. http://www.fototime.com/576C4CAD42E4BFB/orig.gif

[Kmot]

Okay, time to quit foolin' around and pull out the big gun! http://www.fototime.com/81505A877F7B999/orig.gif

I wanted to keep the boat light. It ran well on 8 cells with the Fully motor. When I tried it on a 6-cell pack it fell on its face. I was going to try the Speed 600, but instead went to the parts bin and pulled out a Mega Mini 3. :cool:

The Mega can take the heat. The 540 car motors can't. So I am dropping down from a 10 turn to a 3 turn. http://www.fototime.com/35F57C59C529234/orig.gif

I had to remove the crappy Deans plug and wires and a bunch of excess solder (purchased motor second hand). Then I soldered on a proper Sermos connector and wires. Next I had to drill out the pinion gear to a 5mm bore. You know the saying "measure twice, cut once"? I will never, ever, never, remember it!! Dang it! http://www.fototime.com/0C188D64587295C/orig.gif

So I did a bang up job of setting up and boring the shaft coupler. :rolleyes:

Next, I did the same to the pinion and had to figure out what to do about the coupler. I found I could use a brass insert to take up the slack, Whew! :p

So I got the Mega motor installed, loaded up a 6-cell pack and put it in the pool................

Oh yeah baby!! This is gonna rock!! http://www.fototime.com/5332E068E55B964/orig.gif

The boat accelerated harder than it ever has so far. It also glitched like mad, the motor almost didn't shut off and the boat almost smacked into the pool wall. I forgot to add a capacitor. Once I pull the motor and get the cap installed I am expecting it to be much more like a sport boat should be.

We will see. To be continued................

[green-boat]

Now were talkin some horsepower.

[Kmot]

I hope so g-b! :D

[Kmot]

Okay, the 'devil boat' has bested me again. I soldered a huge cap on the motor and took it to the pool. It was moving out pretty good. I was enjoying it. It pulled a peak of 70 amps. After a couple minutes it cut off. Someone let the smoke out of the esc!

I'm going to take a break from this boat for a while. But............

Initially I was not going to put high end equipment in this boat. But after reading about how no one it seems has gotten one to run well, and my experiences so far with it have proved failures I am more determined than ever to get this boat to perform and be reliable. I take it as a personal challenge now.

I am leaving the motor in. It has the power the boat needs. I am going to install an RC-Hydros 90 amp esc and a Spektrum Rx. The Spektrum will eliminate all glitching, and the RC-Hydros esc is bullet proof (90 amps continuous, 450 amps peak).

I figure the guy who gave me the boat had the same frustrations. Poor performance no matter what he tried. It is built in, if you use the default battery tray. I have got past that. But the hull needs serious power to get moving. And that requires serious equipment.

I want to get it to perform better than anyone else has, and to show this guy what the boat was capable of. I know I can do it.

Once that is done, I will pull the equipment out and sell the boat. Along with the "formula" to go fast.

[Shaun Hendricks]

I'm not sure you wanna put that large of a cap on the motor. A smaller cap would react faster to glitch based RF interference and wouldn't have any significant 'reserve' to sump back into your ESC (which may be what killed it, not saying it is, but it could contribute). Essentially, you are potentially dumping power back into your ESC backwards if that capacitor ever develops enough of a 'charge'.

You'd normally see a cap like that on the battery side to give your boat an additional 'kick' of juice out of the hole. That only works so-so and has its drawbacks elsewhere, at least this is true in the car side of things. I did this experiment on my Stampede and ended up stripping out the cap because it performed better without the 'turbo boost'...

I thought I was going a little overboard in my Highwind conversion... I bow to your dedication Tom. Hope you beat the devil. :D

[Kmot]

Shaun, I will take your advice and dump the cap. Thanks! (it was all I had laying around)

BTW: Novak is selling big caps now for their esc's. Also, I have a couple other motors I bought used that also have quite large caps on them. I dunno, maybe they are causing problems!

http://www.shopatron.com/product/product_id=NOV5626/135.0

[Shaun Hendricks]

Those appear to attach to the servo leads. I don't think servos generate enough voltage from the receiver to worry about a large cap, at least not as much as one off your main motor from the ESC! So I'd be less concerned with a large cap on those leads.

The function of the cap on the motor is to eliminate RF interference, and on a brushless, it's something of a waste of time. What causes the vast majority of RF off a motor is the brushes arcing & sparking. Brushless doesn't suffer from that. You get some RF off the motor itself from the pulse frequency but that is limited to that frequency, it's a fairly clean signal good brushless ESC's and most receivers ignore.

If you are having glitching issues, try braiding your servo wires or ferrite coring them. There are some great products for glitchy leads out there including opto isolators, the ultimate de-glitcher.

I would test the ESC with the rudder servo disconnected. If there is no glitch off the motor, reverse the process, disconnect the motor and attach the servo. That test will tell you which component you are having a problem with. If it's the motor, and it has a gearbox, pull the gearbox and try it again. Apparently some gearboxes can generate tremendous RF depending on the metals (or carbon fiber) used in them. I read about this in a plane once... The builder switched to a plastic gearbox and the problem went away!

Good luck, we want video of this beast kickin' tail. :D

[Shaun Hendricks]

I just took a closer look at that motor, it's BRUSHED! Holy criminey, I didn't know Mega even made a brushed motor. My bad, anyway, go for the 3 small cap version, case to +, case to - and - to +. That's about the best way to cap a brushed motor I know of.

[Kmot]

Shaun, I did a little asking around with the guys who are into the intracacies of these motors and electronics.

What I did was a big no-no. You are right, in that my error cooked the esc but not because of voltage feedback.

Some comments I received:


1)The smaller caps do not have polarity and the larger ones do. I think maybe that is the reason.

2)A cap like that will consume power & overload your ESC.
The cap will conduct on throttle apply & act like a short circuit.

3)It causes current spikes, not voltage spikes. Basically, a cap across the leads looks like a short circuit to the ESC. Even shorter circuit then motor wires. Your ESC was working very hard trying to keep that cap charged. If you hooked it up backwards, it was even worse.

4)He may have been better off if the cap was reversed. It would have blown the cap to smithereens, but the speedo may have survived that.

So, once again I have learned another expensive lesson! :rolleyes:

[Shaun Hendricks]

Voltage is the pressure which puts the current 'into' the cap. The higher the 'pressure' the faster it charges the cap. The stored current is what does the damage to ESC. I'm right there with your other advisors.

I didn't pay attention to the polarity of the cap on the motor, I didn't even notice it was brushed! When I hear Mega and 3 turn, I think brushless. There are very few brushed motors down in that turn range that I've seen. I'm surprised you can even get a 3 turn brushed to spin a propeller the size you are using!

I'm really watching this thread with interest now. You're teaching me a lot (in the 'do' and 'don't do' columns that is!)

[Ghost 2501]

looks nice, :) btw have ya started the neppie yet?

[Kmot]

It's a done deal! http://www.fototime.com/A93B05AC2E6E136/orig.gif

I desoldered the cap, and soldered a Schottky diode in its place. The diode is required for the RC-Hydros esc. I removed the AM radio and installed a Spektrum Rx. Zero glitching.

The boat is way too fast for my swimming pool now. I cannot turn around under power, it scrapes up against the walls. It accelerates like mad. I am anxious to test it in open water. :D

Shaun, there are many brushed motors down into the 3-turn range. But none in the typical 540 car motor range. The Euro motors like Mega, and Plettenberg, Velkom, etc made them. Everyone has gone to brushless though. These motors are now vintage. But they are still brutes.

This motor can turn the bigger prop because it is using a gearbox.

[Shaun Hendricks]

Schottky = no reverse... :D

No wonder you're having a hard time steering... LOL!

[Kmot]

Yeah, I have gotten used to no reverse in lots of my boats that use these types of esc's.

[Kmot]

The Blue Streak performed very well in open water. It's speed was the equal, if not better, than a Villain EX. 12-cells and two motors versus 6-cells and one motor. But it had a porpoising condition at speed. I have made some trim tabs and fitted them to the hull. Basically, I think the boat is finished and the restoration can be called complete. ;)

[Kmot]

Trim tabs.

[graphixman]

Any videos of it Tom?

Fred

[Kmot]

Buried somewhere in the Hansen thread is the rest of the story on this cursed project.

But to answer your question, sorry no video.