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Radio Switch Off?

Max Thrust Riot Final Flight

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Kim Taylor12/03/2018 23:16:52
162 forum posts
51 photos

As per the thread title, I believe that it went like this.....................

Up at the patch yesterday afternoon, nice balmy afternoon at home, but a stiff crosswind breeze by the time I'd set up.

The model is (was) a Max Thrust Riot, receiver Lemon Stabiliser, Transmitter Spektrum DX8g2. The radio was powered by a freshly charged 4.8v NiMh, connected via a standard switch harness.

On to the second flight of the day and the wind was creating a few problems, as it always does at our site when it is crosswind, as the strip is on a valley floor between two hills and it gets very turbulent. Anyway, after doing a few circuits and a couple of loops / rolls I decided to call an approach, intending to do a touch & go. All went well on the base leg and the final turn on to the approach, a bit lively but the same as the previous three or four landings (I did a number of landings / take offs on the first pack).

As I crossed the runway threshold at about 10 - 15 ft height, the 'plane started to drift left, so I put in the appropriate right stick, but nothing happened, it continued to drift further, so I opened the throttle to go around and (you guessed it) nothing!! The 'plane dipped its left wing and described that well known death arc vertically down on to the strip.

I immediately realised that the control surfaces weren't responding at all and when I got to the model the reason became clear - it was switched off!!! Switched it back on and the receiver livened up and the controls (those that were still attached) were working normally.

I can only imagine that when I switched on, I didn't push the switch fully home and the vibration and buffeting caused it to slip back to the off position. With the aid of 20/20 hindsight, the switch doesn't feel that positive when moving between on & off, so I guess that's why I'm wittering away here, to advise everyone to be sure that 1. you switch on properly and 2. check the 'feel' of the switch and if in doubt, replace it.

Mine has gone in the bin, along with the poor old Riot which was smashed beyond my desire to fix it!

The post script is that I now need to replace it with a balsa / ply replacement as I'm starting to change over to ic, so I'll post elsewhere for advice on that.

Kim

Geoff Sleath13/03/2018 01:01:56
avatar
2610 forum posts
198 photos

Where did you have a switch on a Riot? I just connect mine directly to the battery with no switch at all. Ah, I see you have a separate receiver battery and don't use the BEC from the esc. I just wonder why you added the extra complication and weight.

Geoff

Kim Taylor13/03/2018 07:47:46
162 forum posts
51 photos

Hi Geoff

The extra switch and battery were a legacy of my originally flying the Riot using an Eflite 'Safe' type receiver, which needed to have a separate supply so that the receiver could be initialised before plugging in the flight pack (and livening up the esc. Otherwise the receiver and the esc wouldn't 'talk' to each other.

Kim

Cuban813/03/2018 08:42:36
1950 forum posts
3 photos

We discussed RX switches at length in another thread recently, and they really can be a seriously weak link in our systems. Adding the complication of electronic, fail safe (?) units also seems OTT to me. I'm looking at using a well fitting and secure 'shorting plug' arrangement for future models, after all, when did you get last get an issue with an XT60 or similar? KISS.

Edited By Cuban8 on 13/03/2018 08:43:38

Denis Watkins13/03/2018 09:42:25
2725 forum posts
137 photos

Your mindset is correct Kim, I think you know that.

There is nothing worse than struggling with a live aeroplane

trying to disconnect a lipo

when a simple switch solves the problem

the disarming plug is favourite

Bob Cotsford13/03/2018 10:29:35
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7215 forum posts
406 photos

I lost a Jabberwok to one of those switches with the built-in charge socket. Like yours, when I got to the wreckage I found the switch in the off position and everything worked once switched back on. I now prefer to use two battery feeds with individual switches on anything large enough to carry it and avoid any switches that don't have a pronounced detent action.

Geoff Sleath13/03/2018 10:43:59
avatar
2610 forum posts
198 photos
Posted by Denis Watkins on 13/03/2018 09:42:25:

Your mindset is correct Kim, I think you know that.

There is nothing worse than struggling with a live aeroplane

trying to disconnect a lipo

when a simple switch solves the problem

the disarming plug is favourite

An arming plug is totally unnecessary on a Riot when it's just as easy (and simpler) to disconnect the battery itself, quite apart from finding somewhere to fit it and the added complication. An arming plug may be useful on an electric model when battery connections are relatively inaccessible but not otherwise.

I've had literally 100s of flights with Riots with no battery related problems at all.

Geoff

chris larkins13/03/2018 12:02:47
avatar
159 forum posts
109 photos

I'm not sure in this day and age why manufacturers put the battery hatch underneath the model. There are quite a few Riots at our field and I've lost count of the times that I've seen them placed on their back then the battery connected, then to turn them the right side up the pilots put their arm through the prop arc, and do the same again when disconnecting the battery. We try to encourage pilots to do it all from behind the prop but it's an ongoing problem, in addition having the model on its back puts a lot of stress on the fin/rudder and several have come loose as a result. Having the battery hatch on the top and further away from the prop would make it so much easier, these problems are not limited to the Riot though. A battery arming plug would make it much safer as this could be inserted / removed whilst the model is on the flight line.

The Wright Stuff13/03/2018 12:16:34
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1160 forum posts
225 photos
Posted by Kim Taylor on 12/03/2018 23:16:52:

smashed beyond my desire to fix it!

Great expression. Can we use SBMDTFI for short? it's not quite so eloquent as FUBAR, but more sociable!

Kim Taylor13/03/2018 14:28:35
162 forum posts
51 photos
Posted by Cuban8 on 13/03/2018 08:42:36:

We discussed RX switches at length in another thread recently, and they really can be a seriously weak link in our systems. Adding the complication of electronic, fail safe (?) units also seems OTT to me. I'm looking at using a well fitting and secure 'shorting plug' arrangement for future models, after all, when did you get last get an issue with an XT60 or similar? KISS.

Edited By Cuban8 on 13/03/2018 08:43:38

I wish I'd seen that thread - just might have made me look harder at mine!sad

My WOT4 XL was fitted with a shorting plug, when it was electric. Like you say, an XT60. I gave up on that set up because it was so heavy and causing it to land like an express train and continually caused undercarriage damage. I know it was my inexperience too and the constraints of our strip don't help, making it impossible to set up a nice long shallow approach due to the valley sides and out of bounds areas close to each end of the strip.

Anyway, now converted to i/c and just over a pound lighter.yes

Kim

Geoff Sleath13/03/2018 17:07:34
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2610 forum posts
198 photos

That's interesting, Kim. All the glow to electric conversions I've done have needed the battery as far forward as possible, extra batteries or lead to get the CoG right because the electric set-up was lighter than the intended liquid fuelled engine.

I've found the weight of a model will be fairly constant regardless of the power source because of the need to get the CoG in the same place. The only way to save weight in a glow/electric conversion is to get the tail lighter and that can't always be done . My current build is an electric 58" DB Cirrus Moth with a brushless motor and 4000 mAH 4S LiPo and I'm trying to get anything with weight in front of the CoG for that very reason. On my similar DB Tiger Moth I've had to put lead in the front to compensate for the light motor.

Geoff

Kim Taylor13/03/2018 20:17:08
162 forum posts
51 photos
Posted by Geoff Sleath on 13/03/2018 17:07:34:

That's interesting, Kim. All the glow to electric conversions I've done have needed the battery as far forward as possible, extra batteries or lead to get the CoG right because the electric set-up was lighter than the intended liquid fuelled engine.

Geoff

Hi again Geoff, we're way off topic, but as it's my thread, I reserve the right to flout convention!!

With the benefit of hindsight, I realise that I made two errors when specifying the various components in the electric setup. The first was in sticking rigidly to the 150 watts/lb rule of thumb for sport / aerobatic 'planes. At this power, the thing is like a homesick angel and has unlimited vertical performance - much too much for my needs. The second was to over size the flight pack, as a result of the power consumption and my desire for a 10 minute flight time, I ended up with a 6s 5800 LiPo which weighs the thick end of 1Kg. The flight pack was pushed hard against the firewall on a tray mounted at a 45 degree angle to get the weight as far forward as possible. I didn't need to add any weight to balance.

What I should have done (if I could have been bothered / afforded new LiPo's) was prop it down to around 100 watts/lb and adjust the battery size to suit, which would probably have brought it down to the same weight as it is now with the i.c. engine fitted, but it was cheaper to buy an engine and associated gubbins than to purchase new LiPo's, plus I was keen to go i.c. anyway.

Might have to put it all back again one day, I suppose, but until then...................

Kim

Denis Watkins13/03/2018 20:59:52
2725 forum posts
137 photos

Kim

It is easy to get drawn into misjudgement, and we have all gone over spec and over spend

Two of my best flyers are an 100g 50W, and a 600g that equates to 75W per lb

Both are high wingers near scale, and both do suitable envelope,

You have learned from this and at least you can advise when someone with good eyesight and permission

To fly above our restrictions, needs to know how to go vertical

Paul Marsh13/03/2018 21:05:22
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3243 forum posts
895 photos

In my larger models, I use the Dual battery switch now, This switch costs £20 from Rapid and another battery is £10 is, so for around £25 more, you have redundancy (if you count a normal switch price as £5 into the equation)

For smaller models, it is much harder, due to lack of space and weight. But if you have a expensive model over 15cc, it is worth it...5a_switch.jpg

Chris Walby13/03/2018 22:19:02
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467 forum posts
68 photos

Paul,

Could you paste a link for the said switch as searching the web seems to bring up lots of wrong results crying

Cheers

Gary Manuel13/03/2018 22:48:05
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1593 forum posts
1490 photos

I was also interested in this Chris.

I think THIS is what Paul is referring to. It's also a regulator.

 

Edited By Gary Manuel on 13/03/2018 22:52:24

chris larkins14/03/2018 00:04:51
avatar
159 forum posts
109 photos

I have 3 models fitted with these switches, all from Hobbyking though where they are only £12 (£8.97 in the sale)**LINK**

cymaz14/03/2018 06:46:58
avatar
7597 forum posts
981 photos
Posted by Cuban8 on 13/03/2018 08:42:36:

We discussed RX switches at length in another thread recently, and they really can be a seriously weak link in our systems. Adding the complication of electronic, fail safe (?) units also seems OTT to me. I'm looking at using a well fitting and secure 'shorting plug' arrangement for future models, after all, when did you get last get an issue with an XT60 or similar? KISS.

Edited By Cuban8 on 13/03/2018 08:43:38

Do you mean this one? The weather has been so bad , I’ve not had the chance to get any field testing done..or flyingangry

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