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Old Feb 08, 2011, 04:39 AM
Registered User
Australia, VIC, Cranbourne
Joined Sep 2010
58 Posts
Help!
Silversea ACV400 rebuild

HI All,
Whilst diggin about in the back of my garage I came across this. It would be fairly old, maybe over 20 years!
Anyway a bit more digging and I found most of the parts. Of course the battery is dead as and it always struggled to lift the typical 7.2 nicad battery anyway.

So what works.
The trx an old Acoms 29mhz (on chn 20).
Rcvr: 2chnl Acoms on chn20.
MCU:Futaba MC210CB.
Acoms icAS-5S servo for rudder.
Battery 6cell 7.2v nicad 1400ma (~weight 292gram)

Motor 400/35 Robbie.
Twin blade prop thrust and fwd.
Skirts nylon like kite material looks fine.
I got a little bit of battery life and all seems to function.

so I need to replace the battery at least to get it operational.
All I have laying around is 11v lipo. Going by the MCU pdf I found the max it will handle is 8.4 so I best not use one of those. Ill have to buy one

For now I guess Im after a 7.4v lipo? but not sure on ratings etc. id like to maintain power and runtime but loose some weight. Lipo should do the job.

Worth changing the prop?
motor?
Things sure to be more effecient /powerful/lighter nowadays?


Long term thoughts. I have some 2.4g radio gear lying around.
Thought was to buy a brushless motor and matching ESC and really make this baby rip.

appreciate any input, not really played with hovercrafts much and fairly new to RC all up.
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Old Feb 09, 2011, 02:46 PM
Registered User
Australia, VIC, Cranbourne
Joined Sep 2010
58 Posts
Quick update for anyone following.

Im an idiot! it took a real calm night(rare here) and the inspiration of a helicopter fly. The heli hardly ever gets outa the box cause its not up to even the hint of a breath of wind this side of the planet. but last night it was dead calm so I flew and then it hit me..

Whilst changing batteries I noticed what it was....a 7.4v 1500ma lipo exactly what I wanted for the hc.
The connectors are different but I hooked up with some wire and wow!! its got some punch..

I measured the fully charged float voltage on the batt and was concerned the 8.5v would cook the MCU..it still might long term, but it survived a good few minutes.

So much lighter. the old nicad 1400ma was 292g this lipo is a 2/3 less coming in at 94g Ive never seen the hc rise so high!

really need some space now, and a proper connector to try this baby out properly
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Old Feb 15, 2011, 04:08 AM
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Australia, VIC, Cranbourne
Joined Sep 2010
58 Posts
Got my connector and made up an adaptor lead. BE CAREFULL not all tamiya wiring is the same it seems. My battery pack tamiya polarity looks opposite to all the images I goggled.

Anyway got the beast down the local astro turfed school yard. WOW
its a pocket rocket.. lasted a fair while then the prop fell off.. not sure why will look at it later.
Had a fair go at chasing the kids around.

heaps fun.
Took a photo will publish tomoroz

checkd prop. grub screw came loose. should be an easy fix
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Last edited by upnover; Feb 15, 2011 at 10:05 PM. Reason: photo upload
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Old Feb 17, 2011, 05:09 AM
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Joined Mar 2007
275 Posts
Acv400

i dont use tamiya conecters at all i always use Deans is there a flat on the motor shaft there should be this is where the grub screw goes onto and provides a much better surface to get a grip from interesting lookng model though any vids of it,what type of skirt does it have ?
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Old Feb 17, 2011, 04:23 PM
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Australia, VIC, Cranbourne
Joined Sep 2010
58 Posts
HI Tim,
I have been tossing up converting everything over to Deans. The heli I grabbed the batt off of is all mini tamiya, this hc was the larger. I made some converters up but in the end Deans we will go. I guess Im kinda waiting for the MCU or motor to burn out due to the extra punch the lipo puts out. But by then Ill know its worth it

Shaft had no flat, maybe to allow it to spin if it hits something ? Anyway ill see how it goes. One grub screw was missing and the other was loose. I have replaced them both and it feels snug. Flat would be my next step.

Skirt: I think its that rip stop nylon material, like a kite or the fly on a tent. A bit hard to explain in words the under design. Ill get some pictures up later.

Video: mm it will have to be mbphone type quality.. I also have a spy cam, from my plane, I might pop on there

At the moment I have to make a liposaver. lhs did not have any in stock and Im concerned the kids or even I might drive it too hard.

So Ill add some content but dont hold ya breath

BTW Question: How would you set up the MCU? User maunal long gone. Its MCU has a neutral trimmer and the trx throttle stick is centre returning. Im pretty sure it would be of little use to go in reverse. At the moment on power up it runs the prop fast enough to provide lift. Throttle down and it turns off. Throttle up and she goes fwd.
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Old Feb 20, 2011, 05:32 PM
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Australia, VIC, Cranbourne
Joined Sep 2010
58 Posts
Bit of a blow over the w/e.
Got the lipo saver circuit made and installed no probs. but tried the hc on a local well mown park.. not much worse than a golf green. The hc wouldnt even budge, just not enough air , too much escaping. Went back to the astro turf and it was fine.

Was so disappointed didnt take any video etc.
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Old Feb 21, 2011, 02:12 PM
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Joined Mar 2007
275 Posts
model on grass

i have forund that only bowling green standerd grass is suitable for electric models anything longer and you model will not work as you have discoverd where as the Ic models can go over longer grass due to the increase in power
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Old Mar 17, 2011, 06:20 AM
MHA webmaster
United Kingdom, England, Reading
Joined Mar 2011
207 Posts
Hi, any more joy on this? I reckon you could get it to run on grass if you had a brushless setup as it looks nice and light. It may be the skirt design holding you back too - i presume it's a bag type? Most of the models that i've seen working successfully on grass have used segmented finger skirts like full size racing craft as they let less air out in the event of uneven ground, but you do still need a fair amount of power to get there.
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Old Apr 26, 2013, 10:30 AM
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Australia, VIC, Bass
Joined Jan 2013
71 Posts
Hi there just came across this old thread - if anyones still interested i'm the guy who manufactured this craft along with 4 or 5 other designs -We no longer have any models in production but hope to have a couple of new designs available soon which dont use skirts at all so they work well even on grass and are much faster than the older designs,-stability is the main design issue.
The acv400 used a curtain skirt with bag dividers for stability which worked quite well with hardly any drag -except over grass. -There is no flat section on the motor shaft because these motors have a small dia -2.3mm shaft which would be weakened too much. Also it would be worth replacing the original mabuchi 380 motor as these motors loose efficiency quickly if they are pushed at all, especially with dust and spray in the air.The previous model we produced was called the Thruster which had a fully segmented skirt and separate lift and thrust fans- the thrust unit pivoted for steering. Although it used segments and had more power its performance was still very limited over grass -testing showed best results with a bag skirt as it flattens out the grass to seal the air and slides over it more easily, but over any other surface ie water, wet sand gravel etc the other skirts were far superior producing higher speeds and much less skirt wear.
These models were designed over 20 years ago long before lipo batts and brushless motors were available meaning that they had to be very efficient to work at all -it would be interesting to re-fit one with some new gear to test but the skirt will always be the limiting factor -especially with relatively small models like these.
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