Martin Harris - Moderator
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Posts posted by Martin Harris - Moderator
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I think it depends on the age of the unit. Is it the earlier version that takes higher than 6V?
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I've heard reports of poor performance from capacitor based electronic ignition running on AA cells as they have insufficient capability of delivering energy fast enough. Therefore, whatever the power draw while running, I wouldn't use AA - especially as high capacity versions have relatively high internal resistance which limits power delivery.
If your unit is happy at slightly higher voltage, have you considered LiFe?
P.S. I've found the following RCXEL instructions. Typical consumption appears to be 650mA so I'd aim at a minimum of 1200mAh so that you'll use less than half the claimed capacity. NOTE THE ADVICE TO USE A REGULATOR OR (MY PREFERENCE) SILICON DIODE TO DROP THE VOLTAGE IF YOU USE LiFe:
2.) Selecting a Power Source
I.) 4.8 and 6v volt NiCd/NiMh Packs:
The Rcexl Ignition ver 2.0 is rated 4.8 to
6v a max of 7 volts. A 4 cell 4.8v pack and
5 cell 6v pack with a minimum of 800
mAh is fine and creates a hot spark. The
Rcexl ignition ver 2.0 runs most efficiently
on 4 cell packs and 5 cell 6v pack . Do not
use an old Pack!! If it’s not good enough
for your receiver, it’s not good enough for
your ignition..
If Use 4.8v pack the engines not highest
rotational speed, Also use 6V pack
II) 6.4 Volt Li-Fe(A123) Packs
2cell Li-Fe(A123) The Volts Max of 7.2
volts. Nominal 6.6 Volts, use a voltage
regulator. Or connects one IN4007 diode
to fall voltage the use.
If engines not highest rotational speed,
Also may directly use
III.) 7.4+ Volt Li-Poly Packs.:
We have found that 2cell Li-Poly Packs at
peak charge can be as high as 8 +v. If you
are going to use a 2 cell Li-Poly Packs,
you must use a voltage regulator. Or
Serially connects two IN4007 diode to fall
voltage the use The Rcexl ignition runs
more efficiently on about 4.8-6Volts and
will draw more current at around 8+v, as
well as operate at a higher temperature.
You also have a higher chance of RFI
interference.
In brief in can satisfy under the engine
highest rotational speed touse the quite low
voltage as far as possible
Once again, do not use an old pack to
power your ignition! -
It certainly looks the part. The one thing that’s bugging me is the “optional weight reduction” in the piston - how on earth did they advise machining it?
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A common mistake with the OS style 2 stroke silencers is to assume that the rear nut secures the rear section. It’s a lock nut which should only be tightened AFTER the through bolt has been properly tightened. I suspect that this is the cause of lost silencer parts…certainly a common reason for leakage.
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They will be recycled or reused for less demanding applications.
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I'm intending doing the cycling in flight but keeping a close eye on this pack! The supplier suggested that the imbalance was acceptable but I'm not at all convinced...
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Don't worry Leccy - the drift referred to was regarding an idea to "manufacture" methanol in the home kitchen. I think we can accept that while we're right to be concerned over fuel supplies, there's every likelihood that it won't be a show stopper for the foreseeable future.
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As you're in Germany and David hasn't been on here recently, have a look at https://www.aerocockpit.com/ - I've bought from them and they are excellent quality.
They do a variety of individual items or sets - https://www.aerocockpit.com/supermarine-spitfire-mkix--3017-5- might be of particular interest?
If you're really interested in scale details https://www.aerocockpit.com/supermarine-spitfire-mkix-side-panels-kit--3017-1-5-
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Loads of suppliers on Ebay
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Not all threads have requests to stop discussing a particular drift. I'm sure you missed that.
Please let this drop and let's get back to discussing the future of model IC engines.
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Off topic post deleted
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With equal respect, the drift is in continuing to discuss the blind alley of producing methanol from instructions in a cooking show. They may well have mentioned ethanol, which suitably diluted can be tolerated by the human body - you'll know it better as alcohol or booze.
Continued availability of model glow fuel or its constituents is a valid point - happily these products are readily available although some searching around for suppliers of small quantities might be needed as well as a license to obtain/stock nitromethane.
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HRB have performed splendidly in my, and clubmates' EDFs. However, I bought one recently which was quite unbalanced when received - not had a chance to test it yet, so the jury's out on it.
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2 hours ago, Rich Griff said:
A ww1 nerve/poison gas....
Methanol, that's the word I heard mentioned on the TV program.
I mentioned it followed by a ?
Will watch repeat on Sunday ?
Funnily enough glow engines run on the stuff.
Rich - please read my previous post and respect my request to drop this irrelevant thread drift.
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Rich - there is NO POSSIBILITY that the production of methanol would be featured in a cookery programme. It is a nasty poison, ingestion and even significant skin contact leading to damage to the optic nerve, blindness, brain damage or death.
There is little likelihood of methanol becoming scarce - it’s widely used in industry, as is nitromethane.
Can we please drop this diversion and return to the topic of model aircraft engines.
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Yes, rapid chargers are expensive - how much of this reflects their installation and running costs, I wonder, and will increasing competition reduce prices? On the very rare occasions that I fast charge (3 partial recharges - typically 40% of battery capacity i.e. @ 25kWh - in 15 months of ownership) it reduces the economy to somewhere in the region of the equivalent of 30 mpg for that amount of the energy used on the journey.
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How true.
On Saturday, the best flying day in (short term) memory our pits area was full of foam EDF jets with just a handful of EP propeller driven models. The only internal combustion engines were propelling members' cars - and even then, the proportion of electric cars arriving at the club is steadily increasing. I had nearly taken a "proper" model but due to a bit of ongoing personal maintenance work, I needed to avoid lifting too much so I let the IC side down as well.
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It's not a bad reason to go into business. However, most profit on batteries comes from sticking a label on the package so in these cases, function and reputation probably take precedence.
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Yes - by all means do. While this thread stays primarily focussed on Laser engine matters and without any unwarranted personal comments we’re quite happy to leave it to run.
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Simultaneous charging of installed batteries often fails due to the charger’s “intelligent” features finding leakage paths or something similar through the common “earth” connections on the model which appear to confuse them and cause early charge termination. This can occur when using multiple chargers as well.
I’ve found that using separate power supplies (e.g. mains on one and batteries for others to ensure separation) can allow the use of two or more chargers simultaneously - e.g. dual receiver batteries and onboard glow.
The excessive freshly charged LiFe voltage can be tamed by means of a decently rated silicon diode in series with the supply lead (beyond the charge point). This typically drops @ 0.6V with a very good reliability risk - 2 additional solder joints versus multiple components and connectors in a BEC solution.
While LiFe do have a flattish discharge curve, their state of charge can be discerned from an accurate voltage reading but given their energy density, can usually be over specified by a large factor compared with nickel based batteries giving a huge margin over the 700mAh packs which would give a comfortable day’s flying in years gone by.
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Welcome to the forum Robin. I’m afraid Mike hasn’t been on here lately so he’s unlikely to pick up your request.
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Not sure off hand but likely to be a standard metric coarse thread? However, prop nots tend to be a fairly high grade steel so you might do better by approaching the spares agents (elect?) Model Shop Leeds.
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My personal experience and observation is that assuming you were at a reasonably competent skill level when you were flying previously, you’ll find that you’ll have little difficulty picking up again.
Like riding a bike or learning to swim, the muscle memory seems to imprint pretty permanently. A simulator is certainly good for initial learning and one might give you some confidence but I doubt that you would need anything special.
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I can only hope that the whingers were under the impression that you had a financial interest in the firm and didn’t know that you were simply an employee, Jon. Perhaps you might get the odd apology if any of them are big enough.
Now that this is clear, it’s to be hoped that such comments will stop and you can immerse yourself in your new career direction. I do hope you can start to rediscover the joys of modelling purely for your own pleasure and relaxation very soon.
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6V Ignition system for petrol engine, NIMH AA or Sub C and capacity?
in All Things Model Flying
Posted
Whatever solution you end up with, I would recommend flying a few sorties and then measuring the remaining capacity to give an accurate idea of your maximum safe duration.