RunRyder - Fail safe for our gassers ?

rrTV-PHOTO

New HD TV

HOME rrTV-PHOTO GALLERIES MY GALLERY HELP-FAQ

myHOME PM pmRR MEMBERS 643 ONLINE 20 EVENTS SEARCH REGISTER START HERE

3 pages [ << < ( 1 ) 2 3 NEXT >> ]

909 views

POST REPLY

ZoomsHobbies	.	HeliHobby	.	Ron’s HeliProz South
	.		.

Gasser Model RC Helicopters > Fail safe for our gassers ?

ozace
Key Veteran
Location: melbourne, australia

Recently i have started playing with 1/5 scale petrol powered cars.
One of the first additions to the machines is a failsafe that cuts the motors on loss of signal, loss of power or as a remote kill switch.

The part itself starts life as a dimension engineering pico switch which is modified to perform the above functions. Weight of the part is only grams.

The question is, does anyone run one or see a reason not to run one ?

One of my biggest concerns with the gassers has always been the motors ability to keep running without radio power (no Spektrum failsafe) and to run for a long time.

Thoughts and comments please.

we can never have too many, can we ?

07-27-2008 09:29 AM

ozace
Key Veteran
Location: melbourne, australia

http://www.davesmotors.com/store/product2505.html

this is the pre modded version but there is plenty of info for the DIYer (from the guy that does the modding in the link above.)
I have done one myself (for a car) and it takes 10 mins with basic small soldering equipment.

we can never have too many, can we ?

07-27-2008 09:32 AM

windy62
Heliman
Location: USA

Both PCM and the new 2.4 ghz systems offer a failsafe. It is generally recommended to set it to engine OFF.

windy62

07-27-2008 12:47 PM

TVAILLANCOURT
Senior Heliman
Location: Edmonton Alberta Canada

I run failsafe on throttle on my 2.4 and also have remote electronic kill for motor incase something mechanical fails IE. servo fails or linkage pops off.

07-27-2008 03:40 PM

windy62
Heliman
Location: USA

If your servo fails or your link pops off, doesn't the carb close? Mine on the GSR is spring loaded to shut it off.

windy62

07-27-2008 05:29 PM

thtoyman
Senior Heliman
Location: Gone ,Flying.Mich

loss of signal, loss of power
You can have one with out the other.
Loss of power you make you have loss signal.
But loss of signal does not mean you loss of power

To cover it both you will did you use 2 dif ones.
you can use add for the radio. But that does not cover loss of power.as if your battery pack drops.or bad wire ,bad cell. bad switch.

I look to see what I'm use on my cars and boat. I know one of them will kill the motor if pack drops or for bad swith.

For my self I found out radio failsafe's will not work in all case's.

07-27-2008 07:48 PM

ozace
Key Veteran
Location: melbourne, australia

Quote
Both PCM and the new 2.4 ghz systems offer a failsafe. It is generally recommended to set it to engine OFF. windy62

If you have a power failure you have no radio failsafe, thats why on the cars we have the modified pico switch, it needs power to allow the motor to operate, if the power fails the switch closes and motor stops.

What got me really thinking is the problems i had with gasser throttle servos on my last gas heli. When the servo went nuts, stopping the motor was problematic (as you can imagine).

Had i had one of these failsafes fitted i could have "pushed" a button to kill the motor.

The more i think about it the more likley i will be to add one to the gasser i am now working on.

we can never have too many, can we ?

07-27-2008 10:42 PM

pgkevet
Veteran
Location: surrey UK

There is an aussie distributor for 42 percent who do killswitches suitable..

pgk

07-27-2008 11:42 PM

windy62
Heliman
Location: USA

If the modified pico switch fails, then what?

If your servos are crap, use better ones. If they are getting interference from something (Are you using PCM?), fix it, or what if that interference goes to your kill switch channel?

I would just be concerned that you are creating a new failure point by trying to bandaid something else.....

windy62

07-28-2008 01:40 AM

ozace
Key Veteran
Location: melbourne, australia

Windy, i see you point about failure points.

As a matter of fact, if the switch fails the heli cannot start.

So far of the car guys running them (much harder environment than a heli)only one report of failure (due to bad workman ship).

we can never have too many, can we ?

07-28-2008 01:46 AM

AceBird
Elite Veteran
Location: Utica, NY USA

Quote
Had i had one of these failsafes fitted i could have "pushed" a button to kill the motor.

What button do you push if your radio link goes down?

You can put a simple 6V relay in line with the kill wire that stays open or close depending on the state you need so if the battery source goes below 3 or 4 volts it will drop out and kill the motor. If you are using a 4 cell system it likely will not reset on its own if the battery voltage comes back up.

But like the guy says its more crap to go wrong. Go with redundancy, get a generator and forget all the other band aids.

Ace
What could be more fun?

07-28-2008 10:27 PM

Dimitris76
Senior Heliman
Location: Borås, Sweden

Quote
http://www.davesmotors.com/store/product2505.html this is the pre modded version but there is plenty of info for the DIYer (from the guy that does the modding in the link above.) I have done one myself (for a car) and it takes 10 mins with basic small soldering equipment.

Don't need to spend 39 bucks for this product - not for a Pico switch to modify either!

Don't you guys have old/striped analog servos in your junk box?

-Take out the PCB board from the servo
-Unsolder the motor and the potentiometer
-Solder two 2.4kOhm resistors at the pads where the pot used to be connected
-Get a miniature normally closed SPST relay and solder it's coil in series with a diode on the pads where the motor was connected and another diode in parallel to the coil (the diodes' lines should face to each other)
-Connect the black wire from the ignition coil to the ground (crankcase) through the relay's terminals

Congratulations!
You just built your own 50cent ignition kill switch!

1) You can kill your engine with a switch on the Tx
2) You can set the failsafe (if you are flying PCM or failsafe featured PPM receiver) to kill the engine at signal loss
3) The circuit kills the engine at the event of power loss.

Dimitris

07-29-2008 12:06 AM

ozace
Key Veteran
Location: melbourne, australia

Dimi, way to clever and complex for me to attempt but i like your thinking.

Ace, if the radio link drops the engine is cut.

I assume from the tone of many of the posts you guys dont like the idea of a failsafe for the engine, i can accept that.

we can never have too many, can we ?

07-29-2008 12:48 AM

Dimitris76
Senior Heliman
Location: Borås, Sweden

Ozace,

it's just two resistors and two diodes - five minute's job mate... that's as simple as electronic circuits can get!
It's one of these things that are so simple that describing them in words is actually harder than doing them.

Dimitris

07-29-2008 01:02 AM

ozace
Key Veteran
Location: melbourne, australia

You underestimate my simplicity my friend.

When i modded my pico switch i had a pictorial from a car forum to follow. As i have no electronics knowledge i just followed the steps as shown and it works a treat.

we can never have too many, can we ?

07-29-2008 01:06 AM

AceBird
Elite Veteran
Location: Utica, NY USA

Quote
1) You can kill your engine with a switch on the Tx 2) You can set the failsafe (if you are flying PCM or failsafe featured PPM receiver) to kill the engine at signal loss 3) The circuit kills the engine at the event of power loss.

Anything that you connect to the receiver will require another channel that may not be present. It also means any RF issues that may occur might manifest itself as engine problems that may be harder to diagnose for the average Joe Smoe.

I have a seven channel radio for my gassers with a stabilizer and gyro so I will take my chances on the absence of an automatic kill switch function. BTW my radio has a dedicated kill switch function button already.

Ace
What could be more fun?

07-29-2008 05:57 PM

Dimitris76
Senior Heliman
Location: Borås, Sweden

Wait a second Acebird!

what kind of RF glitches are you taking about? If you have serious unsolved glitches you shouldn't fly anyways until you resolve them - thus the kill switch comes in handy.

About the 7 channel receiver - I really don't get it...
You are flying a gasser. That means that you have already invested a small fortune on this hobby and this particular heli and you don't want to spend the money/time/efford to upgrade to an 8 channel one???

And you have spare channels in order to adjust remote gains for gyros and stabilizing systems (all these are nice to have - I admit - but not necessary) and you can't spare one for a kill switch system that can save you and others from death, injury and property loss (plus your own heli from the dreadfull "chickendance"

???

I honestly don't understand how some people are thinking and how they set their priorities...

Dimitris

PS If you don't have a spare channel you can always build the circuit I mentioned above with a 4.9kOhm and a 100Ohm resistor (or easier with a small 5kOhm trimmerpot) and connect it in parallel (with a Y cable) to your throttle channel) so that it kills the ignition only when the throttle AND trim is all the way down. Then set your throttle failsafe there too.
This way you are safe in case a)of power loss, b) faulty throttle servo, c) out of range or other RF issues, d) throttle linkage/ carburator binding, etc...
Worried that a single or random glitches will trigger the failsafe and kill the engine? Use a servo slower between the Y cable and the kill circuit. DS

07-29-2008 09:38 PM

shuttlepilot
Elite Veteran
Location: Mullins, South Carolina

I think a failsafe is a great idea for a gasser. I could have used it the other day when I had mine spooled up and didn't have the battery strapped down properly. I was doing some final adjustments without the canopy after the build. Battery dropped off and the heli was just running about 1/4 throttle. I got a rake handle out of the barn and flipped my kill switch on the engine before things got terribly unbalanced. That's one thing about digital servos, they don't hold position without power....and the cyclic was all over the place. Thank goodness it didn't end up in the chicken dance!!!

Gas is Great
QWW Field Rep

07-29-2008 09:51 PM

AceBird
Elite Veteran
Location: Utica, NY USA

Quote
That means that you have already invested a small fortune on this hobby and this particular heli and you don't want to spend the money/time/efford to upgrade to an 8 channel one???

That would be correct but not for the reason stated. I am a firm believer in simpler is better. I don’t know of an 8 channel radio that is available. When you go to a nine channel you get a hundred other bells and whistles that makes programming more complicated. I can’t tell you how many aircraft I have seen go down because the pilot got confused with his own radio and either flipped the wrong switch or programmed something wrong. Yes these were planks but 5 to 8 thousand dollar jets. That’s four times what I got in my helis. And if you think a heli makes a mess when it hits, you should see a jet. They don’t make crash kits for a jet.

You are obviously comfortable with electrical circuitry. Most people are not. They feel more comfortable with mechanical solutions. I am surprised you own a gasser. I would have guessed you would be into electric power and preaching its benefits. Although, probably not welcomed on the gasser forum.

Quote
This way you are safe in case a)of power loss, b) faulty throttle servo, c) out of range or other RF issues, d) throttle linkage/ carburator binding, etc... Scared that a single glitch will trigger the failsafe and kill the engine? Use a servo slower between the Y cable and the kill circuit. DS

This to me is Rube Goldberg. You are trying to solve a mechanical bind, faulty servo or jammed linkage with an electronic solution??? I don’t have any faith in that. I think there are ways to insure that you don’t have mechanical problems without adding home built do dads.

Safety is a relative term. You insure safety by distance, keep your distance and you will be safe no matter what happens. The second most important rule that will keep you safe is never ever turn your back on an aircraft that is running whether you are the pilot or a spectator. I am sure you have seen many expert pilots turn their back on a running model. No matter how confident you are you never know what can happen, so don’t do it.

Ace
What could be more fun?

07-30-2008 09:14 PM

Dimitris76
Senior Heliman
Location: Borås, Sweden

Quote
I am a firm believer in simpler is better.

That's true!

Quote
When you go to a nine channel you get a hundred other bells and whistles that makes programming more complicated.

You don't have to use them if you don't want to.

Quote
the pilot got confused with his own radio and either flipped the wrong switch or programmed something wrong.

As with everythinhg else, you have to know how your equipment works before you use it.

Quote
And if you think a heli makes a mess when it hits, you should see a jet.

Just because jets make more mess, do we have to let out helis crash full throttle???

Quote
You are obviously comfortable with electrical circuitry. Most people are not. They feel more comfortable with mechanical solutions.

How do you know that? Did you make a study or something?

Quote
I am surprised you own a gasser.

For the record I started 15 years ago with nitro helis, bought over the years my share of electrics and a few months ago bought a Bergen. All them are very complex machines heavily relying both in mechanical and electronic components in order to fly. So I had to master both arts!

Quote
I would have guessed you would be into electric power and preaching its benefits. Although, probably not welcomed on the gasser forum.

But I am not doing that - do I?

Quote
You are trying to solve a mechanical bind, faulty servo or jammed linkage with an electronic solution??? I don’t have any faith in that.

In case you didn't notice that's the trend for the last... 50 years! EFI supervises your car's engine, ABS it's brakes, electronics supervise your (nuclear)power plants'cooling pumps, your kitchen stove/fridge/airconditioner, protect your home from catching fire (aka smoke alarm). And guess what! Your heli's gyro, governor and stabilization system are also electronics. Let me see you turning off that gyro for a while and setting up a mechanical revolution mixer like the "good old days".

Bottom line, there is so much reliability you can get in a mechanical system, so combining it with the inherent reliability of an electronic one is damn' good idea.

Quote
I think there are ways to insure that you don’t have mechanical problems without adding home built do dads

Yes there are ways to make your mechanics more reliable (carefull tuning, adjustments, preventive maintenance, etc) and all of us should do our best along these lines, but unfortunately there is no way to insure that they will never fail. And experience tells me that pretty much everything fails sooner or later.

Home built do dads? Ok hand out 40 bucks and buy a commercial kill switch that does the exact same thing if that makes you feel any better. I just felt like sharing my idea about a cheap and easy to build alternative (that incidentally is based on the same servo technology that you use on your heli). Wait a second! Your gasser is NOT home built? Do you a have a team of certified aeronautical engineers and technicians to set up your bird?

Quote
The second most important rule that will keep you safe is never ever turn your back on an aircraft that is running

I don't recall advicing anyone to build my circuit and turn his back to the heli...

07-30-2008 10:13 PM

3 pages [ << < ( 1 ) 2 3 NEXT >> ]

909 views

POST REPLY

Century Helicopter	.	MTA Hobbies	.	Model Rectifier Corp
	.		.

Gasser Model RC Helicopters > Fail safe for our gassers ?

PRINT TOPIC

Advertisers

Subscribe to This Topic