How smooth does it run on the gas? Does that balance shaft do its job?
L-Plate Rider
How smooth does it run on the gas? Does that balance shaft do its job?
Forum whore
The gas runs smooth, yesterday we had a small problem with the gas regulator not getting any warm water, didn't take long for the regulator to ice up and the engine stop. The ballance shaft weights are a little heavier in this engine as are to crank weights, seems to make the engine very smooth. This ballance shaft is now gear driven off the crank.
Muddler/Dabbler.
Would altitude increase the icing effect on the regulator? I'm really talking about the engine when it's used on a fixed wing aircraft, say 8000 feet - I'm guessing the gyrocopter doesn't normally operate at very high altitudes?Originally Posted by Flettner
Looks like you are having quite a lot of success so far!
Meanwhile,down here at the bottom end of the scale, my successes are a bit thin on the ground. Tried to melt some ally on my furnace yesterday and to cut a long story short, after half an hour it didn't actually do that!
So back to the drawing board to try to design/make a bigger burner (maybe?), I dunno.
The problem as I see it, was that there was an orange flame coming out the top which to me suggests not enough air, however it didn't work well when I adjusted the choke to give it more air, it just seemed to cycle between a great burst of flame then dying down again, that cycle happened every 5 secs or so.
The burner did work well when it was out of the furnace, having a nice steady roaring blue flame almost invisible in the sunlight, but when in the furnace it produced more of a hissing sound.
Possibly I just need to learn how to tune it properly!
Any experts on burners here? (specifically LPG gas burners).
Low personal B.M.E.P.
I don't claim to be an expert Wil, but are you actually putting the tip of the torch inside the crucible ? What you report sounds like the typical result of the flame exhausting the free oxygen available to it - dies back - a fresh surge of air arrives and bang it's back up again. Get it occasionally with an oxy/acetylene torch in a confined space. Shouldn't you be heating the crucible from underneath ? If you are heating from underneath, but inside an insulated furnace, you need to allow air in to keep the flame going.
Alternatively, you're low on LPG....
Who You Calling a Pig
No furnace expert either, but I do like playing with fire. I agree with Grumph in that it sounds like you are staving the flame.
Are you forcing the air in? Or just relying on natural draw?
For the record Qkkid was in my bed, not the other way round
Muddler/Dabbler.
Thanks Grumph,
New 9kg bottle of LPG, a classic furnace type (designed and built by my good self), the crucible sits on a refractory concrete pedestal. The burner tube comes in at a tangent beside/under the crucible. I used a silicon carbide tube for the tuyere (tweer?) with the burner a nice snug fit in it (achieved using cylindrical spacers) on the OD.
Dropped the lid earlier and broke it, so I just had some ceramic wool with a hole cut in it on the top but I doubt if that made any difference (or did it?).
The way the burner performs out of the furnace I think would be adequate to melt at least aluminium, and I think you're right about the air situation, maybe i should try to let more air in by removing or maybe drilling the spacers on the OD, however they are needed to take up the slack and actually hold the burner securely in the ceramic tube.
I think I might have invented an LPG powered pulse jet here!
Any suggestions will be welcome, i'm a complete newcomer to this technology and i'm not a "by the book" type of person - sometimes I wish I was, but where's the fun in that?
Muddler/Dabbler.
Sorry Plumba,
Didn't see your post, yes natural draw, I figured it didn't need forced air for just aluminium and I don't think i'm wrong.
Actually, just thinking about it - when I first fired it up, quite a while ago (ie when I didn't have the ceramic tube) and had the burner sitting loosely in the hole, it worked well with a nice blue, almost invisible flame coming out the top - now I think that may be telling me something!
I think you guys have pointed me on the right track.
L-Plate Rider
Hi Will, you should not need extra air coming in around the outside of the burner tube, your gas jet may be too big for the size of mixing tube you have. I have a gas fired furnace, it works well for aluminium or brass. I'm based at Tuakau if you are ever in the area look me up.
regards Mike T.
Anorak
I can't remember where, but there is a rule of thumb of naturally aspirated forges, for the air entry size outside of the burner dia
Kinky is using a feather. Perverted is using the whole chicken
Muddler/Dabbler.
You could well be right on the jet size,
I originally had a home made jet with a 1mm hole (from memory), then I saw an assortment of MIG tips on Trade Me and bought them, I think the one I'm using is 1.2 mm and I can't remember if I used that one or the 1mm when I first fired it up, anyway I'll check it all out.
That however doesn't explain totally why it still works quite well outside the furnace -the flame maybe isn't quite as stable as it was on the smaller jet, but when it's set right it's fine.
I could possibly be out your way soon, but I'll PM you well before I head over, I would be interested in getting a few tips and I can see that I will probably need more than just a few useful tips (no pun intended) if I'm going to learn this sort of stuff properly!
Muddler/Dabbler.
Thanks Husa,
I'll have to try and find that data - I'm not one to sit down and digest screeds of information! I tend to try it first and if it works then I'm happy, never mind the theory! .......On the other hand, when I can't get things completely sorted, that's the time to listen to those experts - not the correct way to do it I know, but it often saves a lot of reading and researching and trying to decide who's theory is right or wrong.
Forums can be good though, with help from everyday types of people.
Who You Calling a Pig
I would run the same set up and force a bit more air in with Air compressor/Leaf Blower/Vacumm Cleaner etc. Pretty quick test to see if it resolves the issue.
Actually I have an electric leaf blower in my shed that is taking up space and would be perfect for the task if anyone wants the dam thing
Muddler/Dabbler.
Yeah true, but with the setup I have they say that attaching a blower doesn't work, dunno why so I may still end up trying that.
I have a blower taking up space in my garage too, never use it but it's just about powerful enough to blow the furnace away! My wife's got a decent "industrial" size hair drier which I've got my eye on!
Forum whore
A vacuum cleaner, bit of old exhaust pipe, needle valve and fuel, works well. Air is adjusted by a bit of scrap sheet metal on the suck side of the cleaner, fuel by the needle valve. Fuel pump pressure is via gavity. Melts alloy very fast.
Forum whore
Very stressfull day today, sorting out all the little problems with the BIG boss looking over my shoulder all day. BUT finaly at the end of the day target RPM, smooth, safe exhaust temps, safe water temps, although the gearbox breather needs to shift to stop it leaking oil out. Interesting to note gas needs about five degrees more advance than petrol.Autoflight Ltd trying to save the world from global warming, by shifting the planet out to a higher orbit
First of the two heat ranger engines on the test stand, electric throttle testing.
All the more difficult running with a gas caburetor, without any real adjustability. If I drank whisky I'd be drunk by now!
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