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HK Small Bolt Hydro same as HOTR

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Old 05-10-2011, 05:17 AM
  #1026
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Default RE: HK Small Bolt Hydro same as HOTR

Hi sdz,

Cheers mate. I'm so close to throwing in the towel here you would not beleive.

I now have 2 wrecked hulls, 4 duff nano tech's, 1 ballooned Turnigy, 4 blown cheapo ESC's and a Tx Rx combo all in a couple of months ! The balance tabs on these nano's have corroded away.

In answer to your question, this was with the new Tx but old Rx.

I think this hull is a total loss. Its been compromised in so many places I cant see it going back toghether nice at all so the only answer is a new hull.
HK have them for £45 delivered by EMS and astec have them for £55 delivered. I'll also need 2 new nano's to keep going on 4S which are £25 so looking
at £70 to get the hardware in aside from the work involved.

I spoke to my vendor and he suggests the followiong -

Quote:
The flysky probably says it all - 2.4ghz is blocked by water and water spray. That's why we use dual RX's on boats.. Liquid plastic can get in to the joints and I don't know what the carrier will do. You need to use an approved electrical insulator such as electronics grade silicon (not bathroom sealant which has an acid in it) or a conformal coating . The ESC would have shut down on signal loss so it is more likely to be your RX reacting to lost signal. What is the failsafe setting? On some futaba you can set it manually, on Spektrum it is the position you bind at.
I'm not usre but I am inclined to think it is an Rx issue but I cant tell if its water ingress as the thing sank and was wet anyway. I'd love to get to the bottom of this behaviour.
I wonder if I had the failsafe setup if this incident would have been avoided.
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Old 05-10-2011, 06:11 AM
  #1027
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Default RE: HK Small Bolt Hydro same as HOTR

Just another thought - could 2.4Ghz systems get interfecence / reflections from the water ?
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Old 05-10-2011, 07:22 AM
  #1028
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Default RE: HK Small Bolt Hydro same as HOTR

I believe a test for the failsafe would be to shut down the transmitter while still operating a servo or esc. Whatever occurs then is what would happen on the water. As far as reflections and are they detrimental, I can't say. But this doesn't seem to be happening at large, at least it hasn't been documented as far as I can tell. Portable phones and wireless computer routers all work in the 2.4ghz range and could jam your signal except for the fact that Flysky is supposed to frequency hop if connection is lost or interfered with. I wish I could help in this mysterious dilemma. Maybe I should hold onto this last Airtronics radio and not sell it so soon. []
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Old 05-10-2011, 07:40 AM
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Default RE: HK Small Bolt Hydro same as HOTR

Cheers sdz,

I've ordered another bare hull from HK. Its £15 cheaper than getting one in the UK. I have to wait for it but that will be cooling off time.

I may still try to salvage one of the 2 hulls but Bolt 2's damage is more severe than bolt 1.

If it is down to the Tx Rx 2.4 ghz and water then I should have listened to astec in the first place and gone for a DX6i and the ETTI esc and saved a few quid.

I'll test the FS, if it works then great.

according to some reading and advice, 2.4ghz is blocked by water and water spray so this in theory could well be the issue but it does not explain why I have had several decent runs with no issues.
I'm quite confused ! Spektrum have brought out a marine ESC to deal with the issue.

It might just pay to hang on and see how the FlySky works out for you.

I have it on good accord to silicone up those Rx's like in the pic I posted some time ago. Apparently conformal or spray on doesnt like sharp corners. Mine also has bubbles in.
In future I will be using non acetyl silicone. Its what the ETTI ESC is covered in and seems very good indeed.
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Old 05-10-2011, 07:51 AM
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Default RE: HK Small Bolt Hydro same as HOTR

Rake, i'm pretty sure the water interference/jammed signal theory can be thriwn overboard! I use exactely the same tmx/rx as yours and I don't got any problems on the water, and I had the small bolt for quit a distance, it was almost as far as I could see it, without any loss of signal.
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Old 05-10-2011, 08:30 AM
  #1031
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Default RE: HK Small Bolt Hydro same as HOTR

yeah same here on a few occasions nick, then this.

if this is the case what made my bolt lose control ?
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Old 05-10-2011, 03:52 PM
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Default RE: HK Small Bolt Hydro same as HOTR

The small bolt is $98 on HK website but its on backorder [:@]
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Old 05-10-2011, 11:55 PM
  #1033
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Default RE: HK Small Bolt Hydro same as HOTR

I'm not sure but I think the error was not caused by signal interference, but due to a malfunctioning electrical component. My first thought it the RX because this tells all the other things to work.
Maybe a stupid question:but was you able to steer the bolt when it was racing into the wall? if so, than the rx seems to be no victim.
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Old 05-11-2011, 01:49 AM
  #1034
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Default RE: HK Small Bolt Hydro same as HOTR

Hi Nick,

I do now think it was the Rx.
The Rx I was using was the one that went to the bottom of the pond for a month from Bolt 1.
It bench tested ok but looks like practical use was impaired.

The antanna wire has some damage close to the PCB which might well have led to degraded signal.
The damge seems to be limited to the shielding but I cant be sure. Other than this it could have been component failure etc.

Nevertheless it seems to be the Rx at fault.

Before she crashed the steering jammed once. When she was going full throttle out of control steering was not possible.

I will stick with the flysky but I will now use non acetly silicone for waterproofing as opposed to liquid plastic / conformal coating. The ETTI ESC is waterproofed like this and they seem bombproof.

Alot of the racing community here reccomend use of dual ant Rx's due to the 2.4ghz interference from water. They set these up at 90 degree angles from eachother.

I've een reading alot on the web about water and 2.4ghz systems and the general consensus is that 2.4 does not penetrate water and hence suffers signal loss if the ant or rx is
below the waterline.

[link=http://www.rcsailing.net/forum1/showthread.php?4738-2-4-Ghz-and-Water]2.4ghz test[/link]



[link=http://searchnetworking.techtarget.com/answer/Is-24-GHz-affected-by-rain-more-than-56-GHz]Is 2.4ghz affected by rain ?[/link]
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Old 05-11-2011, 03:35 AM
  #1035
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Default RE: HK Small Bolt Hydro same as HOTR

FHSS - http://en.wikipedia.org/wiki/FHSS

Frequency hops all the time, no matter if there is disturbance or not at its current frequency.
FrSky uses this with their ACCST, wich as far as I understand, is more or less a copycat of Futabas FASST

DSSS - http://en.wikipedia.org/wiki/DSSS

Does not change frequency unless disturbance is detected at one of its current channels. Uses 2 or more channels at once at all times.
In general, this is all other systems than Futaba FASST (excluding more or less successful chinese copycats).
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Old 05-11-2011, 03:36 AM
  #1036
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Default RE: HK Small Bolt Hydro same as HOTR

Oh this just gets better and better.

I just hooked up the ESC new lipo and new Rx and the Rx LED wont light up and the ESC is heating up when connected to the cell.
Looks like the ESC is goosed as well.

What did I say about them being bombproof ?
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Old 05-11-2011, 03:39 AM
  #1037
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Default RE: HK Small Bolt Hydro same as HOTR


Quote:
ORIGINAL: Von Ohain

FHSS - http://en.wikipedia.org/wiki/FHSS

Frequency hops all the time, no matter if there is disturbance or not at its current frequency.
FrSky uses this with their ACCST, wich as far as I understand, is more or less a copycat of Futabas FASST

DSSS - http://en.wikipedia.org/wiki/DSSS

Does not change frequency unless disturbance is detected at one of its current channels. Uses 2 or more channels at once at all times.
In general, this is all other systems than Futaba FASST (excluding more or less successful chinese copycats).

Thanks for your input Von Ohain.
Excuse me for being a layman but how does this translate to the issue I have had ?
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Old 05-11-2011, 03:57 AM
  #1038
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Default RE: HK Small Bolt Hydro same as HOTR

The post was a reply to sundogz input regarding 2.4ghz and its resistance to interference (from doppler effect of its own signal, and lockout due to water spray).

The simple answer is: You wont get jammed by anything, wireless routers, water spray, phones, or the phase of the moon, wether you DSSS or FHSS.
Theoretically, FHSS is more resistant, but in practice, you wont get shot down by anything if you using a serious radio utilizing either of these modulations.
Many DSSS systems also use multi channel broadcast, to compensate for its lack of native frequency hopping. giving it double or even triple channel redundancy.
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Old 05-11-2011, 05:22 AM
  #1039
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Default RE: HK Small Bolt Hydro same as HOTR

Von Ohain, thank you for pointing out the difference between FHSS and DHSS. I was saying FHSS but describing what DHSS did.

Rake, I think the quality control on these Flysky Rx's is not so much. So far I've installed/tested 6 of them in boats and one didn't respond at all. I'll check the others soon as I get time. But with the cost so low, it's not a big deal - just buy extras. Now if they test good and suddenly fail, that is not good.

Do you have a second Rx that you can test with the Etti esc? That one I described does the same - it doesn't light up or bind.

I use [link=http://cgi.ebay.com/Hobbywing-Seaking-60A-Brushless-ESC-Boat-Version2-/140359810080?pt=Radio_Control_Parts_Accessories&hash=item20ae18bc20]these 60a esc's[/link] in the jet ski's and have never had a problem with them. They can take 120A bursts. HK sells them as Turginy Marines.
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Old 05-11-2011, 05:26 AM
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Default RE: HK Small Bolt Hydro same as HOTR

There is a 'new'(?) product from hobbyking. the HK310 with FHSS, for GBP 39 (+P&P). But the TX's are expensive, about 16GBP.

But after reading posts above from sdz and Von O. there is just one thing that keeps spinning through my mind.
We first had only 27mhz and 40mhz AM/FM systems,  and after reading all the info about FHSS and DSSS etc. I have the idea that the 27mhz and the 40mhz systems must be really awfull and occur problems.  But in my opinion it wasn't. I never had problems with my boats even with 27mhz AM system.
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Old 05-11-2011, 05:39 AM
  #1041
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Default RE: HK Small Bolt Hydro same as HOTR

According to the submarine guys, 2.4ghz (very short wavelength) doesn't penetrate water very far/well. They use AM or FM interchangeably. 2.4ghz excites/is absorbed by water spray - like what a microwave oven does to water in food. Which doesn't matter much if you are higher in elevation that the boat, or if you're operating an airplane. But if water spray is between your boat and Tx, you could have problems.
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Old 05-11-2011, 05:57 AM
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Default RE: HK Small Bolt Hydro same as HOTR

I tested with 3 Rx - the ESC is goosed too.
astec thinks the BEC has blown and it has to go back to ETTI.

This is all getting rather expensive !

I've already ordered the new hull so I'm in for another run now. I guess this is either leading to another ESC as the repair turnaround is 6-8 weeks from HK.

What I really need to do is ensure this wont happen again.

I hope that activating the failsafe will do the trick.
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Old 05-11-2011, 06:22 AM
  #1043
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Default RE: HK Small Bolt Hydro same as HOTR

Rake, you might ought to check out [link=http://www.bbyracing.com/elecmicrohulls.asp]this microhydro[/link] (bottom of page) made by BBY, at least until you get this interference problem worked out. They are made of ABS plastic, can be repaired with CA glue, and most importantly can take a lot of punishment - much more than brittle fiberglass. And they are inexpensive as well. I own a BBY Oval Master (jet drive) and have run nose on into rock, etc and it just bounces back. I have managed to chip a tiny piece off the nose, but it is still structurally intact. I would leave the 'turbine canopy' off as it looks like crap to me. I know I'll take some heat for this, but it will keep you on the water, for less $$.

And do consider the Seaking esc. At HK, the are the [link=http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7360]Turnigy Marine[/link] esc's. And I see now they are rated for 380a! burst.
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Old 05-11-2011, 06:30 AM
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Default RE: HK Small Bolt Hydro same as HOTR

I dunno mate,

Now that I found the ESC to be blown I think I wanna take a step back, take a deep breath and hit one of those tequillas you mention from time to time.

I really need to get to the bottom of the "outa control thing" real fast.

None of you guys seem to be having this issue and I have had great runs on the FS gear in the past.

Now i'm beggining to understand why I have 2 blown servo's too, the ESC BEC perhaps ?
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Old 05-11-2011, 07:15 AM
  #1045
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Default RE: HK Small Bolt Hydro same as HOTR

The 2 blown servos are what throws me. Unless they have been underwater or have been fed too high a voltage, servos are the least likely thing to go bad. As I shared a while back, I had an Etti esc that went bad, and Etti fixed it for free (then I sold it - I had lost confidence). Tell you what, if you get that Turnigy Marine esc that I linked to from HK, and it ever goes bad (short of known human error) I will send you one of mine. That's how much faith I have in them. They are not too large for the boat and the peace of mind will be worth it.
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Old 05-11-2011, 07:28 AM
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Default RE: HK Small Bolt Hydro same as HOTR

Nickster (Off topic warning!)
There is nothing wrong with neither AM or FM (Narrowband), and nothing wrong with the frequencies they operate at either.
Their philosophy is that you got a dedicated frequency, and as long as that frequency is clear, then its all happiness.

That doesn't work anymore. RC hobby isn't just for gentlemen anymore, any idiot can buy a radio, turn it on and shoot down your plane, abusing your frequency.
It shouldn't happen if everyone were organized in clubs and followed the rules for frequency use.
But that isn't whats being done in practice.

So DSSS and FHSS (Spread spectrum) (also modulation types, like analog AM, analog FM, and digital PCM previously used in rc) solves this by using modulation types that is natively resistent to interference on the same frequency. Narrowband is excellent as long as you got a clear channel. But if you don't, you are far better off with DSSS or FHSS.
In theory, you could use DSSS and FHSS on 27MHz, 35MHz, 40MHz, 72MHZ and 75MHz as well, but in practice these frequencies is ususally reserved by law for narrowband rc use.
So operating a FHSS transmitter on 35MHz would work fine for you, but you would shoot down all other narrowband users in the whole 35 MHz band!
Not good. Therefor they use 2.4GHz for spread spectrum, because its a legally open band.

So how can multiple radios all use the same band at once, all operating spread spectrum within the same band? Won't all receivers receive signals from all transmitters?
Yes, they will!
But each receiver has a unique adresse, wich is what the reciever obtains when you bind it to the radio. So each receiver will only accept commands from a transmitter with the correct address, even if many signals is received.
And the truly unique thing with DSSS and FHSS is that FHSS jumps across multiple frequencies all the time, to find a frequency that is free for that split second. Just enough to get commands through, before jumping to next frequency.
DSSS broadcasts on 2 or more channels at once, and modulates its signal with a high frequency pattern to scramble the transmission across a broader band.
So not only does DSSS have redundancy against interference simply by using 2 or more channels at once, but its also transmitting on a wide band within each frequency, so the likelyhood is that some part of your broad band transmission is getting through, even if a narrow band is blocked my another transmitter.
And the last barrier for DSSS is that the scrambler signal witch broadens the frequency, also is a known pattern to the receiver, and the receiver will only accept signals scrambled by the very same pattern.

Short summary:
While AM and FM works well, as long as you got a dedicated and open frequency, DSSS and FHSS assumes that you got no open frequency at all, and instead they use multiple frequencies at once, and several additional other redundancy systems to ensure that interference wich it inevitably will receive, does not get through the receiver.
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Old 05-11-2011, 10:49 AM
  #1047
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Quote:
ORIGINAL: sundogz

The 2 blown servos are what throws me. Unless they have been underwater or have been fed too high a voltage, servos are the least likely thing to go bad. As I shared a while back, I had an Etti esc that went bad, and Etti fixed it for free (then I sold it - I had lost confidence). Tell you what, if you get that Turnigy Marine esc that I linked to from HK, and it ever goes bad (short of known human error) I will send you one of mine. That's how much faith I have in them. They are not too large for the boat and the peace of mind will be worth it.

Throws me too sdz but is a picture starting to emerge ?

First 2 servo's then the thing goes nuts and I lose the ESC / Rx ...

Could it have been the esc all along ? I bet I wont get an answer thats definative
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Old 05-11-2011, 11:12 AM
  #1048
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(sound of crickets....)
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Old 05-11-2011, 12:11 PM
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Quote:
ORIGINAL: sundogz

(sound of crickets....)
I'm lost - you mean no answer ?

I'm a transmission engineer by trade so using basic troubleshooting techniques I'm coming to the conclusion that the esc was to blame all along.

regarding 2.4ghz and use on water - on my chosen lake I am well above the boat.
The ant is well above the water line and has clear line of sight at all times.

2.4 only suffers when ther is no line of sight or the ant is below the water level and its also due to the frequency being so high that it cannot penetrate the surface of the water which n this case is not the case.

the history -

I get the esc and using the FS Tx / Rx all is well for 8 runs on 2S.

the rudder then breaks so I strip her down and install the new HW.

I come to use the old 4800kv motor and find that the bearings are rusted so need to reprogramme the esc for 4s (2600kv) when I find that the esc wont respond to the full break during programming.
I then find that there is no servo response with 1 servo.

I plug another in, it gives a bit of forward backward and then nothing.

this lead me to think it was the Tx so I take it to the LHS who tries a new servo and we discover that it works suggesting that I have 2 blown servo's, one of which must have blown on connection to the esc as it momentarily worked.

Next I install the new servo, bench test and take to the water.

the servo jams, the bolt goes out of control and crashed.

this Rx has worked flawlesly on numerous occasions so why all of a sudden would it begin to suffer from signal loss out of the blue ?

also, the lack of response to full break is almost akin to the lack of response before the crash.

I've used 2 Tx, 3 Rx, 3 different lipos but the ESC has always been the same one.

How to prove -

If I had a crash test dummy I could use all the same hardware with another esc.
Even the stock esc would do for this test but as I have to split hulls I have no method of doing this test.

Anyway, thats my deduction but pretty hard to substanciate without all the electronic know how and test kit.


Regarding the seaking, I might just try that thing while waiting for the navy to come back but it only goes to 3S lipo when I wanted to run 4S.
Having said this motors are cheaper than lipo's so will think about combining with 3600kv as an option and going 3S.






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Old 05-11-2011, 12:27 PM
  #1050
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It could be the BEC that isn't supplying sufficient DC voltage.
And by sufficient voltage, I dont mean just the DC voltage itself, but also the magnitude of a ripple component.
Do you use a ferrite ring on the signal cable between the ESC and receiver?
Also, try with a RX battery pack, or separate ubec.

I always use OPTO ESCs, and even if the ESC has bec, I cut the red wire, and use a separate BEC anyway.
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