Nigel R
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Posts posted by Nigel R
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As noted above, glow motors often lose RPM at low speed without the driver. If the idle is reliable without it... well, who cares? Worry about nailing the full throttle tuning, and getting idle + transition reliability, everything else is not that important.
Just thinking aloud about factors affecting the ignition timing on our glow motors, there are a lot - heat of engine, heat of plug element, element wear, element composition, fuel/air mixture, how well the carb atomises the fuel... adding or removing a glow driver to the mix changes that balance by adding heat to the glow element + advancing the ignition point.
Worth noting that automotive diesel engines - which also rely on compression ignition - use direct injection at terrific pressure and can time the injection squirts to affect ignition timing. We have none of that control!
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What vapex cells are they? They do "standard" and low discharge types (marked as "instant" i think).
Your results look about expected for standard type. Although the variance is quite large.
Low discharge are better for our purposes, in my opinion. Those should show 80pc of the rate capacity when cycling at 2C.
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Used to? Still do on some of my needles...
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Model Technics Laser 5 - is 5% nitro 15% synthetic
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Enya are good motors, but less common, and I think spares may be an issue.
Os and saito are far more common.
You pays your money etc.
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I concur about brand choice, for second hand.
End of season, run the engine dry off possible. That's the only after run precautions I ever take.
Jons advice is all spot on.
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Or use less throttle stick?
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25 minutes ago, Simon Chaddock said:
Nigel
I fear you have hit the nail on the head.
I am sure IC engines will continue to be produced for many years but as you point out without a high volume the range of engines will reduce and the cost will go up..
Whilst this may no be too much of a problem for the current users it could mean a bleak future.
After all has not the same sort of thing happened with ARTF and particularly with moulded foam scale?
Accurate highly detailed electric power and maybe a "multi" at a price likely not far removed form the cost of buying the materials and parts to build the same from scratch.
I'm just saying what I see Simon; I agree entirely with what you say.
Everyone wanted ARTF, so we had ARTF, now ARTF is too expensive for a lot of people and the volume goes down. ARTF were very cheap, artificially I suspect (because various global/political factors which have now changed), and now they are not cheap, and shifting in lower volumes. I agree, a similar problem, but market forces are what they are.
Balsa and glow?
Perhaps, liteply and petrol.
Times change. None of us can predict the future. It will not be so bleak as all that. Just... different.
Maybe in 10 years, turbines will cost 1/2 what they do now... 10 years ago, a foamie jet with a tiny turbine was still sci-fi.
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On 31/03/2024 at 20:01, martin collins 1 said:
One of the models i am working on at the moment is going to need a RX pack for the receiver and one for the Ignition, i am looking at either a 2s LiFe pack or a 6v Eneloop, what are the benefits/drawbacks of either in this choice, which one would you pick and why?
Depends.
How big is your model?
How many servos? What kind of servos?
What is the engine - single cylinder 2 stroke? Seven cylinder radial?
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I can't see there being much money in small engines. Without money there will be no commercial offerings. There is money where there is mass market, and some where there is expensive fancy sunday bests. The expensive fancy sunday bests are no longer mid-to-large size glow, instead that seems to be big petrols, going up to massive motorbike sized petrol radials for 1/3 scale warbirds, then there are turbines, etc. The mass market in small engines? Might be something with RC cars I guess.
Everyone wanted electric. Now we have electric. Electric power makes props turn round but is quite dull. Electric does not have the mechanical beauty of a finely engineered IC. That's ok if you don't really care about the motor as a toy in and of itself; if you simply want to plug in a battery and fly. Not everyone wants a swiss watch, but, anyone who wants to mess about with small engines is the minority and the minority does not get a diverse selection of manufacturers vying for our cash.
I also don't see very many on here rushing out buying new small or mid size glow motors (with the exception of some Laser aficionados, although that has now ended, not sure what you guys are going to splash out on now. OS? Saito? Move up to a big Valach?
20cc and up is still dominated by petrol, so that's an indication of what people want, in that size. The 2 strokes are easy enough to operate and probably cost a lot less than electric, following recent price rises on electric clobber. Seems to be a future there.
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Not worth messing with it, I would agree with the above posters suggesting getting rid and replacing
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18 hours ago, Tosh McCaber said:
Thanks for thatDick!
As well, has anyone recommendations/ illustrations as to how to fit standard servos in each wing? Brackets, or?
Make some hatches in the wing from thin ply, fix some wood blocks to the hatch, mount servo to the blocks.
Or some pre-rolled:
Lots of ways to skin the cat.
Or, just fit the upright and let the servo arm stick out into the breeze, this is usually the quickest way.
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Given the cozy relationships between manufacturers and their regulatory bodies we have seen in various industries in recent times I'm not so sure we do know how to do safety critical engineering any more.
Not every aviation company is in that place.
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I should say, despite what you might think given previous postings, I do find the whole field of manned multirotors interesting. I simply don't think that going off half baked, with people inside these things, over places with people living in them, is the right answer.
It isn't 1903, we're not the Wright brothers, this isn't precisely a new field of knowledge we're exploring and discovering, and we do know how to do safety critical engineering.
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Because replication and redundancy comes with its own issues, it's not necessarily easy, and in life-or-death scenarios such as this, a glib sales pitch means squat.
If there are two spare rotors going up, now you have a problem regarding re-routing power around between the other rotors? You've added complexity to the control systems now. Are the rotors truly redundant? As in, any and all mission scenario is possible with one or two not working or not present? Or "redundant", as in, not really redundant, but you can limp down to the ground without fatal impact? Whatever the answers - taking three copies of multiple systems up into the air is cargo you don't want to be carrying, that's reduced range or time.
End of day, I wouldn't say it's extra safety in the slightest - far from it, they're doing this in order to meet basic safety needs of the cert basis. Why repeat a system three times otherwise? Customer pays extra for extra copies.
As an aside, and this is a total straw man argument - the kind of language you are seeing from these kind of places is exactly the same as was seen from that ill fated Titantic tourist submarine. At its core, it was a sales pitch of "it's brilliant, because <waves hands like Paul Daniels> technology". They also thought taking multiple copies of mission critical systems onboard was "extra safety", too. And don't even mention the technology (or total lack of) in the hull of that death trap.
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Not going to go into much depth but I will say that including the redundant copies of various bits of hardware makes me extremely suspicious of the quality of the parts being duplicated in this manner.
Another way of putting it is, they are so certain these critical parts will fail, they are fitting extra ones to take over when it happens.
This doesn't feel like a project that is inspiring confidence in its basis for certification.
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16 hours ago, IDD15 said:
I see only 18 moving parts in the Volocopter and probably three maybe even four times the redundancy over a single rotor helicopter.
You cannot (and, nor can I) simply look at a picture and say "I see more redundancy therefore must be safer" because the actual safety and actual engineering behind both those craft is totally invisible to a casual observer, which, I think, is what you and I both are. The real value in any aircraft is in the guarantees that certification provides. Neither of us know what Velocopter have got in the bag so far - although I will note they are late with their TC.
6 hours ago, GrumpyGnome said:No auto-rotation possible ......... wonder what happens if it loses power.......
Splat.
Or more likely, a parachute pops out the top and it lands on the nearest field/person/house.
1 hour ago, Cuban8 said:Modern helicopter technology and engineering are very well understood and reliable and have proved to be suitable in a wide variety of environments.
Got it in one.
If, and it does look like quite the big if right now, multirotors can beat helicopters as an overall package, then they will win out.
And I will fly to my job at the nuclear fusion power plant in one. 😈
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1 hour ago, Flying Squirrel said:
Having an open mind on the whole subject of drones and personal flight vehicles clearly puts me in the minority on here!
Lots of naysayers and general hatred to ANYTHING 'drone' related from most people involved in other aspects of the hobby of RC Flight...perhaps they feel they are to blame for the increase in regulation etc
The necessity of Certifying a multi rotor for use in anywhere you'd actually want an air taxi will quickly sort out the dreams and reality.
We already have multi rotor full size aircraft. Count them on the fingers of one hand. Then compare to the numbers of single rotor helicopters.
Minimum viable thing here is basically a Hughes 500. Etc.
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Routine emergency does are already a reality.
Bunch of horse manure from an mp.
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looks great fun!
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Well done to all involved with Laser for bringing some true quality engines to our hobby.
As the late great Douglas Adams said - so long, and thanks for all the fish.
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brilliant bit of kit
yes, makes dust, and this needs dealing with (somehow)
Best petrol engine for a Seagull Steen Skybolt
in Beginners
Posted
Just checked the stats on this, its listed as 61" and 9lbs finished weight. I'd go for a 120 glow four stroke. Plenty on Ebay as a second hand.