Flame out at 3 feet.

[DDragon]

Well, I think it's a flame out. The turbine stopped working... but here's the background information.

I've been testing and setting up with my DX7 and got her pretty well where I liked her. Incidentally, following Bell's instructions, I set the mid-point 3 at 70% (hover +5) and put her on a tach and found my RPM was around 1700-1760 so I think that's good for 710mm blades? But I had the max rpm set to 130,000 rpm on the turbine (not 135,000)... does that make sense?

Anyway... it was working fine like that yesterday on the DX7. Since I figured I would get only one more day in before it got too cold... I decided to re-setup everything for my new JR X9393.

WELL... that's when the problems started to happen. Since I had to re-set the throttle for this radio anyway I decided to change the max rpm to 135,000.

Then after setting up my pitch ... (+5 hovering at point 3) I then set the following:

Point L = 0%
Point 1 = 43%
Point 2 = 60%
Point 3 = 70%
Point 4 = 80%
Point 5 = INH
Point H = 90%


With these settings I found the heli not as stable and for some reason the engine would "flame out" (not sure if it's a flame out, but I'm assuming it is)... under these circumstances:

1) If I dropped the throttle suddenly from point 3 to Point L too fast the engine would cut out. No flame.

OR

2) I'm just hoving and all of a sudden the rpm speeds up a little (I'm not increasing it) then it "flames out" all of a sudden. Sounds like a fuel pump issue, but I'm no expert.


Anyone experienced this before?

Well just for the hell of it, I put the max RPM back to 130,000 rpm on the ECU and set my throttle cures to:

Point L = 0%
Point 1 = INH
Point 2 = 60%
Point 3 = 70%
Point 4 = 80%
Point 5 = 85%
Point H = 90%

I ran two tanks through her and didn't get senerio 1) or 2) as above. Also, it seems more stable in a hover. But that could be anything.

So I don't know... is it something I'm not doing or should do? Like "Don't Drop the RPM all of a sudden" or you'll flame out...

I'm more worried about a flame out when everything seems fine (senerio 2). I really don't think it's an air bubble because I'm running a felt glunk, a UAT and the inline filter before the turbine.

Would anyone like to venture a guess? I think I fixed it by using the above throttle curve, and by reducing the RPM to 130,000... so I don't know. Maybe that fixed it. Maybe I was lucky.

Opinions welcome.

Oh... forgot to mention. This winter I plan on removing all bolts one at a time, and using locktight and makign sure it's in... it seems everytime I go for a flight SOMETHING falls off. It's kind of funny. I bolt uscrewed itself today.

[Bell Bloke]

There should be no way that you can get that engine to flame out no matter how much you bang the throttle stick about. So can go from full power to idle to full power as fast as you like and the engine should never ever flame out, so you have so other problem. I don't understand how you have set up your throttle but then I don't have a JR. Your original DX7 set-up sounded good to me, but the flame out thing needs to be investigated.

[Bell Bloke]

Oh I think I see, you have 7 point curves and you are converting across to 5....is that right?

[DDragon]

Oh I think I see, you have 7 point curves and you are converting across to 5....is that right?

That's right.

Here's my DX7 throttle curve.

Point L = 0%
Point 1 = 60%
Point 2 = 70%
Point 3 = 80%
Point H = 90%

This is with a max RPM of 130,000.

The headspeed is tached at 1700-1760 rpm at point 2 (mid-stick) for 710mm blades.

[chopper jockey]

Quote: I'm running a felt glunk, a UAT and the inline filter before the turbine. un-quote

Deron,

You may also be "over filtering" your fuel. The pump will have to suck very hard through that lot. A UAT on it's own will be more than enough filtering and will be easier on the pump.

[Bell Bloke]

Chopper Jockey has a point, although I thought you had run this engine quite a few times without any problems. Are you sure your battries were not low? You can send a download to Wren and that will immediatly give you your answer, and it will take out any guesswork. ;-)

[DDragon]

Quote: I'm running a felt glunk, a UAT and the inline filter before the turbine. un-quote

Deron,

You may also be "over filtering" your fuel. The pump will have to suck very hard through that lot. A UAT on it's own will be more than enough filtering and will be easier on the pump.

Hadn't thought of that. But Bell was right. It was running ok before. Maybe I should remove the inline filter?

[DDragon]

Chopper Jockey has a point, although I thought you had run this engine quite a few times without any problems. Are you sure your battries were not low? You can send a download to Wren and that will immediatly give you your answer, and it will take out any guesswork. ;-)

Hadn't thought of that. But I don't have the cord to download it? So what do I need?

[DDragon]

Just for hahas... yesterday I was raking up all the leaves in my backyard and noticed these "strips" of yellowed grass. I was trying to figure out... what the he11 are those?

Then I realized :rollingit's the scorch marks from the hot gasses of the turbine exhaust where I touched down! I really love this turbine!

[dave peers]

yup im banned from running mine in the wifes pride n joy THE GARDEN
first fire up with my dad around
second fire up with my boys around
third fire up flying mate around
HEY PRESTO !!!!
4 days later sargents stripes across her lawn n her threatening me with the carving knife
n leaving me, if i do it again, divorce is SO expensive these days ,another turbines cheaper SAHRA NOTHER WREN 44 FOR ME please!

[Bell Bloke]

We get crop circles here in historic Avebury, are you sure that the marks were not 'extra terrestrial' That's what I tell my girlfriend, and she seems quite happy with that......

Ps. I would leave all of your filters in until you get a download, and for this you need a lead, then you can email the results to Wren

[DDragon]

yup im banned from running mine in the wifes pride n joy THE GARDEN
first fire up with my dad around
second fire up with my boys around
third fire up flying mate around
HEY PRESTO !!!!
4 days later sargents stripes across her lawn n her threatening me with the carving knife
n leaving me, if i do it again, divorce is SO expensive these days ,another turbines cheaper SAHRA NOTHER WREN 44 FOR ME please!

LOL... it's just too temping isn't it? I like when the propane starts, then the kerosene kicks in...

[helibeli]

How high would the engine have to be to not burn the lawn?

[Matt Jenner]

it would have to be in the Hover,

the blades down draft the exhaust,

i also found after a few starts in the garden 2 brown V patterns, at my club i was blamed for the same pattern apearing , i refused to accept it was me,:dontknow until i smelt the grass and it smelt of Kero.... GUILTY AS CHARGED...:banana

[helibeli]

It's only when you read threads like these about burning patches on lawns that you realize the potential for a major fire if you were to fly in open countryside on a hot dry summer's day.Remember the amateur rocketeers on the news a couple of years ago?The rocket went up then horizontal and set the moor on fire.!

[Matt Jenner]

yeah you are right Helliebelli, thanks for the comments on curves on the other site, the old timer was about to go off on one again...:thumbdown:

I personally would not fly in a cut corn field...

I think personally here in the UK our grass doesnt have a chance to turn brown as we dont get the heat in summer...

I always have a CO2 extinguisher with me when i fly...

I expect it is no different than petrol in gasser machines...

Matt

[DDragon]

OK... I was able to cause the flame out. If I hover (about 1-2 feet from the ground), then either drop the too fast, or almost about to hover (lite on skids) then drop it down quickly it will cut out. And it doesn't have to be much of a drop, I can cause it by dropping it just a notch (slightly below mid-stick).

I recalibrated the radio (hi, lo, off) and tried it with a full tank or almost empty. Same thing happens.

When I look at the fuel line I can see bubbles most of the time. There are no bubbles in the yellow fuel feed lines.

I'll take a few pictures in a minute, I had to move the pump to the back, and I'm using grey fuel line I bought since I ran out of the wren supplied clear fuel line. Maybe air is getting in from the festo joints?

Don't know.

Alos, I have two questions.

1 - I noticed that I have leak from the gearbox, looks like it's coming from the mounting screws. is this normal?

2 - When the engine is off, a little smoke comes from the air intake. It doesn't smell like burnt wires. Is this normal? I guess it would be?

Thanks

[DDragon]

Bell, Ian, Sara, Chris? Here's some video...

http://www.double-dragon-ebooks.com/temp/flame-out.html

It shows the heli hovering twice, in both cases I dropped the throttle quickly and you can hear the engine cutting out as though I had hit the HOLD switch. In the second video I dropped the throttle a single "notch" and the heli dropped and bounced before stopping.

Note: If I reduce the throttle carefully, it won't cut out and will continue to idle. I suspect it may have something to do with the pump, or the tubing I'm using since when it happens... I can find at least one bubble in the fuel line.

Again, I'm using a felt glunk, UAT and inline filter? There are no air bubbles before the pump, I have grey tubing between the pump and solinoid so I can't tell, but there are air bubbles in the clear fuel line after the soliniod.... and in all cases I have a full tank of fuel. But that doesn't seem to matter.

Any ideas?

I'm thinking that as I drop the throttle air is getting in somewhere? Don't know?

Thanks.

BTW... don't mind the big guy, his just the clean-up crew. :YeaBaby:

[Matt Jenner]

2 - When the engine is off, a little smoke comes from the air intake. It doesn't smell like burnt wires. Is this normal? I guess it would be?

I can answer that bit, that is just the oil residue left over form the burnt fuel, it does smoke,

As to the other comments about flaming out when you suddenly move the stick, that sounds more a like curve problem than an engine problem..

When we first run my turbine we delibertaly allowed air into the system to see how big the air bubbles had to get before the engine flamed out, we got them up to a large size, 10-15cm in length, before we got a flame out... unless you have major air leak i cannot personally see that is your problem...

[jimboh]

Hi Deron,

I too have been experiencing identical engine cutout symptoms as yours with my WREN III. I set my DECEL value to 105, but will still get an occasional cut out as I quickly chop the throttle. I am only using the felt clunk and an inline filter in my fuel line. I've sent emails to WREN and some data downloads from the ECU, and they were unable to explain as to why it is doing it. They sent me another pump (FlightWorks) but this did not solve the problem. They recommended that I not abruptly cut the throttle. Being a newbie to turbines and based on this feedback I kind of came to the conclusion that this was not unusual or normal for fast throttle cuts and characteristic of turbines in general so I made a flat idle 1 curve to help prevent any abrupt throttle cuts until after I landed.....until I read Bell's comments earlier in this thread where now I am deeply concerned about it again. In the meantime you might try raising your DECEL value some just to see if that helps. Can WREN comment about this being normal or not and what potential causes could be for the benefit of any one encountering this symptoms??

regards,
jimboh

[Bell Bloke]

Sorry Guys but it's not a curve problem, it's not any kind of 'software' problem... in fact, there is nothing that you could ever do wrong with you curves or pitch or speed of opening and closing the throttle that will ever, ever cause your engine to flame out....ever! This is a simple build problem, you are going to have to find out where that leak is coming from because that is your problem. There should be no leaks at all on the engine or gearbox and there should be no smoke coming from the front air intake. However that said if the engine has just flamed out due to an air bubble then smoke might come from the air intake as it was an 'unsceduled' shut down and it upsets a few things fuel wise inside so you can get vapours from the front. But this is not nornal and must be looked at. As far as this tubing goes I would bin it and get the correct stuff since this sounds like your problem.
Jet engines will only flame out if
1. your batteries go flat.
2. you run out of fuel.
3. you get air in the fuel line, because engines can't run on air ( if you ever get one to run on air you will be a very rich man).
or 4. Your engine will also flame out if you land in water.


So the golden turbine rule according to Bell Bloke is your jet will never flame out, so long as the pump pumps the fuel and there is fuel to be pumped, simple.

Good luck maty let us know what happens ;-)

[DDragon]

Sorry Guys but it's not a curve problem, it's not any kind of 'software' problem... in fact, there is nothing that you could ever do wrong with you curves or pitch or speed of opening and closing the throttle that will ever, ever cause your engine to flame out....ever! This is a simple build problem, you are going to have to find out where that leak is coming from because that is your problem. There should be no leaks at all on the engine or gearbox and there should be no smoke coming from the front air intake. However that said if the engine has just flamed out due to an air bubble then smoke might come from the air intake as it was an 'unsceduled' shut down and it upsets a few things fuel wise inside so you can get vapours from the front. But this is not nornal and must be looked at. As far as this tubing goes I would bin it and get the correct stuff since this sounds like your problem.
Jet engines will only flame out if
1. your batteries go flat.
2. you run out of fuel.
3. you get air in the fuel line, because engines can't run on air ( if you ever get one to run on air you will be a very rich man).
or 4. Your engine will also flame out if you land in water.


So the golden turbine rule according to Bell Bloke is your jet will never flame out, so long as the pump pumps the fuel and there is fuel to be pumped, simple.

Good luck maty let us know what happens ;-)

I have pics of the fuel line I'll post in a few minutes.

Matt, my air bubbles are pretty small at about 2-3mm... they only seem to appear after a flame-out.

Bell, the tubing is the correct size and it's festo made, for jet planes. But I'll call Sara and get the right stuff over the next few weeks and replace it.

What about the lub leak from the gearbox? That's was assembled at the wren factory, so it's not a build problem on my part since I didn't build it.

Curves... I've programed a number of curves to see whats, what... one is flatter than the other.... but I seem to only remember having these problems when I switched from the dx7 to the 9303. Going from 5 points to 7.

I'll see if the curves help on the weekend. Gets dark here before I get home, so the weekend is my only chance now.

[DDragon]

Here are some pics of the fuel line routing. It shows the fuel pump mounting angle, furl line to the value and a sample of the bubles I get.

I'm thinking that when I "chop" the throttle down, the pump may be creating a slight vaccum that pulls in air from the festo joints if the tube isn't cut right, or maybe too hard. The grey plastic tubing IS harder then the clear plastic tubing from Wren. so..maybe?

As mentioned, I don't recall having this problem with the stock fuel line from Wren... so maybe that's it? But I only started noticing thisproblem when I switched radios.

BTW anyone... hows' the angle of the pump? Shouldn't be a problem I think?

[Bell Bloke]

Jimboh, restore all factory settings on your Fadec, you don't need to mess with them, that is 'your' reason for flame outs. The Wren fadec settings should not be messed with EVER!! Sorry but this particular subjuct does wind me up, here's why.....
Now I am going to change this story slightly to save embarrasment for those envolved....
I went to a Club where a very respected expert and brilliant flier was setting up somebodys Wren engine, the trouble was it was flaming out all over the bloody place....Why because he was messing about with the Fadec settings and was chasing his tail all the time. As a result the guy he was teaching thought the engine was troublesome and I just had to stand there and watch this bloody fiasco. Why? Well because I do have a good deal of respect for this chap and I was not about to embarras him in front of his pupil, and would he have listened anyway, well probably not.
I always say to people who want to mess with the settings........if you were to buy an Aston Martin, would you plug in your laptop and start changing all of the injection settings timings, ignition timings etc? Believe me you wouldn't. Even companies that do it on a professional basis normally mess something up...........SO, please restore your Fadec settings and post them here just so we can check, if that is OK? Sorry for the lecture but you got me on a bad subject.
The only settings you need to touch is the Max rpm and the glow plug. I don't care what 'expert' up your club or whoever told you to change the factory settings, if you put them back your engine will work again. :-)

[DDragon]

Hi Deron,

I too have been experiencing identical engine cutout symptoms as yours with my WREN III. I set my DECEL value to 105, but will still get an occasional cut out as I quickly chop the throttle. I am only using the felt clunk and an inline filter in my fuel line. I've sent emails to WREN and some data downloads from the ECU, and they were unable to explain as to why it is doing it. They sent me another pump (FlightWorks) but this did not solve the problem. They recommended that I not abruptly cut the throttle. Being a newbie to turbines and based on this feedback I kind of came to the conclusion that this was not unusual or normal for fast throttle cuts and characteristic of turbines in general so I made a flat idle 1 curve to help prevent any abrupt throttle cuts until after I landed.....until I read Bell's comments earlier in this thread where now I am deeply concerned about it again. In the meantime you might try raising your DECEL value some just to see if that helps. Can WREN comment about this being normal or not and what potential causes could be for the benefit of any one encountering this symptoms??

regards,
jimboh


Hi JimBoh,
I emailed sara (order some new tubing too) and asked for an explanation. What's the DECEL value controll? I hate changing anything I don't know anything about.

I'm with you, as long as I'm careful I don't get a flameout. But I'm sure I did the same thing with my DX7 and I really can't remember any of these problems. I recently moved the pump to the back and extended the fuel line, so it may not be the radio switch over.

What kind of radio are you running? Does it have 5 or 7 throttle points?