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advanced engine instrumentation ?


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Not mad, but over-zealous. At the moment you are going at the whole game like a bull at a gate.

 

You obviously have either experience or interest in structural matters and material sciences, as well as your keenness to get into the air in your own aircraft. However there is a big difference between the highly technical aspects of structural analysis and going to buy a $100 hamburger, which is a main aim of recreational flying.

 

As Facthunter, an very experienced member of our community has said, " flying the PLANE and keeping a good watch OUTSIDE is paramount in U/L flying " . In the next few months you are going to be pounding the forum with questions related to getting your certificate, and there will be a crowd of experienced pilots and maintenance people to put you right. How about concentrating on getting your certificate first before your start diving into the minutiae of aerodynamics and aircraft systems design?

 

Crap. The aim of RA-Aus does not to be going to buy a $100 hamburger. The aim might be to have fun monitoring the engine. I actually dislike flying but am learning how so I can travel to places that are inaccessible by land. Facthunter said to keep your eyes outside the plane. That is very good advice, and easily observed by having making sure that you *can't* observe any of the parameters from inside the aircraft. This is consistent with the monitoring of heavy machinery where, I imagine, the powers that be make sure that the operator cannot be distracted by information beyond a warning light.

 

I imagine that Jabiru might give you a very warm welcome or a very cold shoulder. I would be more interested in what Jabiru said that the engine monitoring! I wonder if they cooperate with you if they will want you to not make your findings public? I expect that they would be able to tell you which bits of the engine to monitor. If they were willing, or not, to tell you what to monitor, that would be interesting. I wonder if there is something measurable that would alter the TBO? I imagine that that is one of the main ideas in monitoring other things.

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Glen I like your enthusiasm and obvious knowledge and experience in the commercial end of embedded and a sensor areas. The biggest thing about aircraft is to KISS. There is a very wide line on costs as it is with any sort of aircraft ownership and operation. Keeping your eyes out of the cockpit is the main thing to worry about. Yes you can log all sorts of everything now with the array of sensors available and depending on how good you are with software you can have some really funky stuff. Then of course there is all the time AFTER the flying to be pouring through logs and graphs to be looking for something that may have a effect in the long term. But in the bigger scheme of things the cost to implement this stuff is far out of reach of most with sensors your talking about and the cost of the hardware design and implementation. Most private aircraft rarely get to 2000 hrs over its life so this is why you dont see all the gear your talking about.

 

Your better off trying to improve what you have than design what you want....unless you have lots of money and time to burn. The stuff I play with for moding my aircraft really is to improve what I consider inferior to make for more reliable and safe operation. I am not saying dont do what you want but you really have to look at it in a business like environment and its the bang for the buck that is most important. Owning and flying your own aircraft has a large cost attached to it and for most the less you have to spend the better. You only spend what you think with be a big benefit to either performance or usability of the aircraft.

 

If RF guy is able to do the stuff he says he can do, then I'm pretty sure he will be able to work out the cost.

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They removed over 1/2 of the warnings on the B 747 that affect take off because they were a danger and they have 3 people to monitor that and it's in controlled airspace. There ARE times when a warning may be an expensive distraction and some of them are inevitably FALSE.. You are trying to MANAGE a FLIGHT primarily and as a priority. Engines and even the structure is expendable sometimes in order to keep the lives of people more safe.. I look after engines probably more than most always during my flying career (start with little throttle observe warm up shut down from slow rpm, climb at higher airspeed if temps going up, etc). Your engines no good if you crash the plane it's in and you are taught how to handle engine failures wherever they happen and NO engine is guaranteed not to fail or run out of fuel because you are lost, or didn't notice some one pinched some of the fuel last night. Nev

 

Good point. I stand corrected on my earlier comment about warning lights. Just have *none* of the information available in flight, including warnings.

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The one thing about machine-learning / classification jobs , you need alot of data.

 

Yes, I will certainly have fun running up all the monitoring points, and observing later.

 

For something accurate like "engine supernova in 5 seconds" light, that needs alot of data of good and bad conditions. - the classifier needs training on all things.

 

For general purpose offline monitoring, as to see what the general health of your engine is , then analysis of the data can provide very useful without knowing very much about what you are doing

Just looking for data that shouldnt or should be there. - I mean such things as looking for unusual reflections in TDR (indicating media discontinuities), and things like listening to the intake/ exhaust noise for valve issues. Looking at thermal gradients, or unusual hot spots etc. Many possibilities.

 

As for Jab (company) . yeah I dunno. let's see how it goes. Got to get a license and plane first. And the weather has been very unkind to learning to fly the past few weeks.. Will start looking for a used J120 when I get my ticket. J160, J170 sort of in no-mans land for my mission profile.( I've read some of their flying differences here in the forum topics) .J170 has sure higher MTOW than the J160 but permissible CoG range for J170 at MTOW is insanely miniscule Really want a J230 that's a nice easy to load plane, but maybe one thing at a time, lets just see whether I actually like flying myself, or not ! :-) . oh it should be possible to determine loaded CoG from stress and travel/ deformation measurement in the landing gear. Maybe. on level surface. The plane will have a weight on the three wheels that varies with CoG, surely. what have a missed ?

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You can put me down for a cheap vibration measuring setup and also an icing warning. The icing warning would be difficult though. It is not simply cold temperatures but a combination of factors. Still, a carby temperature reading would be interesting... I wonder what temperatures you would normally see?

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While the likelihood of icing can be well estimated from atmospheric parameters, fuel temperature, carby body temperature (which all together might be good enough), there is likely no substitute for looking down the throat of the carby with sensors to see the problem .

 

- but a pilot would normally recognise icing conditions would they not ? with air temp, pressure, humidity, density available) ?

 

My guess is a combination of all those sensors could produce a warning.

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Carb icing and fuel vaporisation are transients that leave no trace after they ruin your day, normally. I'm a bit of science and analysis guy but play with your stuff or fly the plane... Your choice. Putting it bluntly. Get a carb heat that meets the requirements and use it properly and have baffles and directed cold air and a back up fuel pump and a gascolator, for the vaporisation issues. ALL engines have bad harmonic ranges. IF you know them, stay out of them. IF you don't know, then Find out if you are that interested. Nev

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Any LSA Jabirus you wont be able to modify AT ALL unless Jabiru sign off on it

Find a 19 reg and you can do the type of work youre thinking

History shows Jabiru are reluctant to involve themselves in R&D that they arent running. Some have been told all cylinder EGT and CHT was a bad thing as pilots would knew too much.

They now recommend it

Have a look at what Dynon and others put together, these have a range of engine sensors, logging and limits available. Even with this all set up and running, the outcomes of data presented isnt always clear

Yes you should recognise carb ice and many other issues by feel and experience.

As far as inside cowl conditions, its gets very hot on landing and there isnt anywhere to mount much off the engine itself

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You can put me down for a cheap vibration measuring setup and also an icing warning. The icing warning would be difficult though. It is not simply cold temperatures but a combination of factors. Still, a carby temperature reading would be interesting... I wonder what temperatures you would normally see?

I'll sell you a carb ice alert, adhesive paper - five bucks.

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You should recognise carby ice, but how many didn't and have paid the price. Years ago I used to hire a C150 which had carbie ice if there was a cloud in the clear summer sky. I recognised it, but later a student pilot put it into the ocean, with no apparent faults that could be proved.

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anyone using the Rotec TBI fuel system on their Jab ?

Yep. I have a Rotec TBI carb on my Jabiru powered Corby. At cruise I get a narrower EGT spread than my other Jab powered plane with a Bing carb. At WOT it’s just as bad as the Bing.... the rear cylinders go lean and the front rich unless you back off the throttle a bit and drop 100rpm, It’s nice to be able to adjust the mixture, but the Bing is pretty good & if I had the room firewall forward in the Corby I’d go back to the Bing just for simplicity.

In both my planes I run an MGL EMS, monitoring rpm, oil T & P, carb temp, coil temp, fuel pressure and flow, 4x egt & cht, oat, voltage and current. It’d be nice to have a knock and vibration sensor. I had manifold pressure in a VW powered plane and this was useful in setting a nice cruise throttle position but I find I set the throttle just with fuel flow.

A friend is developing his own engine monitoring system for his Jab powered Drsgonfly. He intends having a large glass screen display. But it is taking him quite some time to get it all together.... he has just received his printed circuit boards from China.

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I'll sell you a carb ice alert, adhesive paper - five bucks.

I flew today. OAT on the ground 8C. Plenty of humidity & unstable gusty air. Carb temp 2C on warm-up, so precautionary use of carb heat used and carb temp rose to 12C for take-off (with no carb heat). At cloud base 4500’ OAT was 3C and carb temp 8C (no carb heat). Carb heat used on descent to keep carb above 20C. Cabin heat would have been nice, but appropriate clothes were sufficient,

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Carb icing and fuel vaporisation are transients that leave no trace after they ruin your day, normally. I'm a bit of science and analysis guy but play with your stuff or fly the plane... Your choice. Putting it bluntly. Get a carb heat that meets the requirements and use it properly and have baffles and directed cold air and a back up fuel pump and a gascolator, for the vaporisation issues. ALL engines have bad harmonic ranges. IF you know them, stay out of them. IF you don't know, then Find out if you are that interested. Nev

Good point Nobags. I reckon the EGT was a once-only benefit to the Jabiru. And the reason is that the carby on the Jabiru is so automatic that there is nothing you can do short of changing things like the feed-ins to each cylinder in the plenum chamber. Well the EGT on all cylinders sure helped with this, but these days it is useless as Nobags suggests.

From my actual experience carb ice on a Rotax UL 80hp in a Skyfox it is not nice, engine running rough, reduced power can not climb or maintain level flight. Just made it onto the runway. Too close and happened on decent. So I always apply carb heat on downwind and turn off late final. Just my experience FWIW.
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Nev,

 

in your post text "and have baffles and directed cold air and a back up fuel pump and a gascolator, for the vaporisation issues"

 

what is the function of the backup fuel pump with respect to vaporization issues ?

do you mean a pump at the tank to push fuel down the lines that might have vaporization ?

In the Datsuns we had to ensure there were NO rising bumps in the fuel lines in hot weather as the pump was at the motor.

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METAL CHIP PRESENT ALARMS- aviation question

 

I remember the dreaded chip alarm light coming on in the Jet Rangers. it meant land, now ! and check ! and sure enough, you would undo the magnetic plug with the metal continuity detector , and there would be a piece of gearbox on the sensor !. take it off, not too big ? write it down in the log, and keep flying.

 

How is this done in Fixed Wing ICE Aviation engines ? Is this done ?

and I would guess there is a different procedure for Aluminium bits since they are not going to stick to a magnet, more needed something like a gauze that traps and you get XY continuity , or something, or some sort of cyclone/ fluid trap that heavy particles go and they get across a continuity sensor... or an inductor sensor to sense aluminium or steel in solution etc.

 

-glen

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Markdun, it seems that you have a carby temperature gauge and you find it useful. Do you use it to determine when to use carb heat?

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On the subject of metal chips, we sure do that kind of check RF. At each oil filter change, you cut the filter open and examine the un-concertinad roll.

You can also use magnets on the oil filter cannister. You can also send a sample of oil off to be tested, but this is really a lycoming thing to do because Jabirus dont have a database of oil sample figures.

I always do the first 2 things. But our engines don't have helicopter gearboxes so there is not so many gear teeth in there.

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RFGuy, something that might light your fire, if you haven't seen it already, is the Raptor prototype being built in the US. An Aussie guy named Peter Muller lives there and for the last several years has been designing and building this aircraft. Its powerplant, believe it ot not, is an Audi 3-litre twin-turbo diesel V6, with a 3rd-party Motec ECU on it. In conjunction with some software this allows him to tweak all sorts of parameters, and monitor/log heaps of things. The aircraft is very close to first flight. Today's update shows him doing some static runs to verify that there will be adequate engine cooling during take-off and climb-out. As you can see, he can collect more data than you can shake a stick at! Not for in-flight use, but very useful at this stage of the project. Peter's background is in computer software, NOT aircraft design. Today's video is below and there are literally hundreds more going back right to the start of the project. I really don't know if this thing is ever going to fly reliably and/or well, but I do respect this guy's persistence.

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Hi marshallarts. Interesting video to watch.

It's looks very slippery. and I like canard aircraft.

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Yes it certainly looks good. Peter estimates (hopes for) cruise speeds well over 200 knots - an earlier video seemed to show that the engine was producing over 300hp at the rev limit he has set (about 3800rpm, with a reduction drive). And it's pressurised too, so with both those turbos pumping, performance should persist way up into the flight levels, and no need for oxygen masks. I think the prototype is quite a bit heavier than it could/should be, so probably won't reach its performance potential. His plan is to put it into production, but not by him. He says some discussions/plans have happened, but they won't be revealed until after it has flown. He has quite a number of deposits for kits - a lot of the enthusiastic followers reckon it's a Cirrus-killer. Well maybe, and maybe not! Anyway, better stop this thread drift, just wanted to make you aware of it. Cheers, Steve.

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Markdun, it seems that you have a carby temperature gauge and you find it useful. Do you use it to determine when to use carb heat?

Bruce, yes. I just used one of the spare ports on the MGL and hooked up an LM335 to it. It is inserted into the boss on the opposite side of the throttle butterfly shaft of the Bing carb. And yes, I use it to assist in determining use of carb heat as a sort of prophylactic against icing, though more often I use carb heat to cool down the EGTs sometimes. Ditto for the coil/ignition unit. My thinking was that as the MGL RDAC has the ports I may as well use them and the LM335 are only a couple of dollars.

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