hyperdyne

My Feedback: (6)

I've been at it again. I got a wild hair to try and come up with something that would be able to alert the pilot to an in-flight flameout. My basic motivation is from experience. I have been bitten a couple times with a flameout that took 5-10 sec easy to diagnose. Those are critical seconds that could of been used to set up a deadstick landing. My last unfortunate flameout was on a touch and go. I didnt hear it with the other planes doing WOT testing, and by the time I figured it out I was out of runway.

Anyway, I thought a loud theft alarm connected to a custom circuit I made would do the trick. The alarm is certainly loud, 120dB worth. I hooked up my measurement circuit in parallel to the fuel valve. It simply monitors whether or not the valve solenoid is energized or not.

Of course the circuit doesnt become active until it sees the solenoid has been energized once (start up). After this if the fuel solenoid shuts down, you have a flameout. And then the alarm sounds.

You can also enable/disable the circuit using an aux Rx channel. In this demo I have it wired up directly to my boomer without a servo input. Also, if your Rx stops transmitting the circuit will always re-enable the alarm (not that you dont have worse problems at that point).

Here's a quick video of it in my boomer.
http://www.youtube.com/watch?v=uQLj-mBEjWA

This is one of those things that I hope to never have to use. But if it goes off, its like a smoke detector - take immediate action!

I hope to fly it soon and get and idea of the audible range.

FenderBean

man you need to patent this I would buy one LOL cool idea and good job

hyperdyne

My Feedback: (6)

Thanks! Probably not a patentable idea because of simplicity, but nonetheless I think it has novelty.

If there is enough interest after I get some flight tests done I can always whip up a batch of them for others.

ira d

What about a system that would release a flag or some type of streamer? With all the noise that can sometimes be at the field you may not
be able to here the alarm either.

3DHELINUT

My Feedback: (3)

Correct me if i am wrong but if you were to run out of fuel or a large air bubble reached the motor you would not get an alarm. the alarm as far as i can tell will not be detected by the pilot with other aircraft in the air.

if there was a ground unit that gave off an alarm than you would have something, good luck with it.



Alan

rcjets_63

My Feedback: (5)

Interesting idea. Well done! I'll trade you a good-looking and maintainance-friendly install job on a Boomer for one.

Jim

Duncan

LOL Jim, I can never understand why people don't care about how neat them make installs, it makes any fault finding so much easier and looks so much better to.

marc s

I'm no expert but how about some kind of temp probe either positioned on the turbine nozzle or directly after, I'm guessing the temp just after a flameout must drop almost instantly?
Might be able to hook into the ECU to tap into temp data too saving extra equipment?

marcs

digitech

My Feedback: (10)

you could use the new jr telemetric for this and set a audible alarm with a set of temperature

bigplumbs

All you need in that install is some mince and you will have a nice bolognese ............. still mine are much better

Dennis

Moerig

Unless you know you are the only one flying using this gadget you gonna know the engine flamed out before you were sure its your alarm. Design a lockout free rx and you have a winner...

hyperdyne

My Feedback: (6)

You would use the same mark I eardrums to figure it out. The brain is good at figuring out sound direction. So your choice is to either figure out your flameout the standard method (guess) with other people in the air or determine if the alarm is coming from your plane and take appropriate precautions. To me it was a simple choice.

You could monitor temp also. I at first was going to monitor RPM but that would be more complicated to do. I wanted to try something simple first to test out the concept.

From my testing, a warbling alarm is very easy to pick up far away - that's why they are used in car alarms. It doesnt have to be loud, it has to be *discernable* from other background noise. Anyway, thanks for the comments.

BTW, I bought the boomer already built, so the install I had to live with. Plus its my testbench plane for my circuits so it tends to get alot of gadgetry. It's my personal rats nest..

hyperdyne

My Feedback: (6)

If you were to run out of fuel, the turbine would shut down - then the alarm would go off. It would not detect an air bubble unless the turbine shut down. Any condition that caused the turbine to shut down and the fuel valve to shut off would cause the alarm.

jetmodeller

Hi why not use a presure switch working off engine case pressure,as soon as engine flames out presure is lost ativating switch!

mr_matt

My Feedback: (10)

The guy has a dead simple way of doing this, why would he want to add , temp sensors, pressure sensors, RPM sensors. etc etc. The turbine has those already.

At least in jetcat's case, that valve will close when the turbine shuts down for whatever reason . Of course the case of a failed ECU or failed valve won't be covered, but that is very rare in comparison.

I think this is a great idea.

marc s

Temp sensor was simply a suggestion, not to be added to a long list of extras -

marcs

hyperdyne

My Feedback: (6)

I wanted to make this thing as simple and reliable as I could. Having a backhaul RF channel, telemetry input, and linking into other sensors makes it all much more complicated. The KISS method was employed here. All of the smarts are already in the ECU to handle engine issues. And if the ECU goes bad and the fuel valve is left on to pump kero into a stalled engine you have more serious problems than the one I am worried about! Also as stated, the probability of this happening are smaller than typical flameout scenarios.

Anyway, the comments are appreciated.

Moerig

If the sound proves a reliable early warning you should probably add a 30 - 60 sec window of the valve being open before activating. otherwise every bad start will kill them ears. Probably you will have to monitor the throt channel otherwise shutting down after taxi will be deafening to all around. While you at it monitoring the throt for failsafe events smaller than the turbine shutdown delay could alert pending lockouts...

JohnMac

You could also look at this device. If I have a flame out the revs will drop below the normal ramnge. I have set my Transmitter to provide an alarm if this should occur. It also will give me an alarm for an overtemp condition, and it also gives an alarm for low fuel state.

hyperdyne

My Feedback: (6)

If you waited 30-60 sec to throw the alarm then an in-air flameout would not be reported until it was too late.

To mitigate the issues you are talking about, the board has a servo channel input so the user can enable/disable the alarm at will. It can use the throttle channel if you like.

I went a step further on my boomer setup, I interfaced the alarm output into my landing speed indicator circuit (http://www.hyperdynelabs.com/products_RC_speedind.php).

Basically, if the plane has 0 (or some low) air speed then the alarm is automatically disabled. So after taxiing and turbine shut down there is no annoying alarm.

Here is a video of the airspeed interface working. When the fuel valve is shut off the flameout board detects this and lights up. But since the airspeed reads 0 the alarm is disabled. Once I blow air through the pitot tube the alarm engages right away.
http://www.youtube.com/watch?v=sRcfnvGq2Os

Jim

Moerig

Sorry I did not make it clear, I meant 30 - 60 seconds at startup only. Idea being that 30-60 seconds is how long it may take to get airborne. Seems you do have the bases covered. would be interesting exercise to see if the alarm would be audible enough. If it is it opens the easiest "telemetry" option out there! Voltage issues can be signaled as a different series of beeps maybe?

hyperdyne

My Feedback: (6)

Ok, I understand now what you meant.

Sure, different warbles could tell you of critical issues. That would be a cool addition.

I am going to do some audible tests in the air here soon. I can drive multiple alarm emitters, since they only weigh 1 oz each. Right now I am only use one, but two may be the answer...