stockdaddy

Yes they are tricky with that. You have to get accurate thrust data to confirm you will get the flight performance you need.

B.L.E.

As if the horsepower claims made for .40-.46 two stroke engines are realistic.[sm=rolleyes.gif]

Quote from the Jett website's explanation as to why they make no horsepower claims for their excellent engines. "It's hard to beat the first liar."

opjose

Lol... yes.

ELTIGRE

I fly both ----you have been mis informed & there is some eggzageration here. batteries are not cheap it is true HOWEVER. they can last much longer than a can of glow fuel ever would . I know, I just tossed two nicad packs that were going on 7 years old. the savings with E is in amortiziing cost over time . operating costs are practically non exisistant with electric. charging does not take an hour. 20 min at most & you should carry more than one pack anyway, 3 at most. the motors practically never wear out.glow costs in plugs , fuel. especially big ones& lots of it. you wont get that much cheaper with the big mills as you think. cleaning costs something too. airframes last forever due to low vibration with electric..

ELTIGRE

here is another guy who has no idea what he is talking about and likely wont learn . Electrics require , with some exceptions , for you to study & calculate power , prop & volt/amp requirements.you cant just slap any old thing in there and expect it to work. therefore electric flyers are more intelligent and knowlegable life costs are lower usually. there are always exceptions you can point to. also electrics work on a principle where they can put out liniar power no gas could hope to and with less vibration .. .further they work very well in a number of situations in which gas however quieted by mufflers would be unwelcomed. there are no clean up requirements & airframes last much longer than glow AND still look good.you know what an amp is ? a volt ? what is the power electricity is measured in? if you say any of the above you are WRONG!

sigrun

You're certainly doing your best with all your disinformation/misinformation.

Reading your post, you even got that wrong. Some? It's nothing but falsification and exaggeration.

How truly s t u p i d is this statement! Doesn't take much of a stretch of the imagination to see where this kind of 'logic' is going to lead.

Anyone who would operate an inexpensive NiCad pack for that long in a critical application, eg: RX or BEC power, isn't anyone whose advice anyone with a working synapse should heed. 7 years! ROTFL. Money must be as rare a commodity in you shop as intelli.....

That's absolutely the stupidist claim I've ever heard...well perhaps not the stupidest, but it ranks right up there as a prime contender for the title. Capital outlay to set up let alone maintain even a modest EP setup is horrendous, and comes nowhere near that of glow IC. eg: A typical quality single 3S 3300 pack costs somewhere in the vicinity of USD$150. That' sufficient to power something which'll provide around the rougly equivalent performance with comparable flight time of a TBR .25 glow engine.

Er...Conventional acceptance of 1C or less or kill your LiPos quickly dispenses with this nonsense .....except according to your 'new math'.

I'm so glad you brought this up, else I would have. Anyone who would call themselves and RC flier needs at a minimum at least 3 fully charged packs of a size which will fit each model they intend to fly, of sufficient capacity and current rating, or as many chargers, balancers, leads and associated other support equipment, and to lug around a fully charged whopping great mother battery unless they have some conveniently close by alternate AC power source with which to power an expensive DC power supply to replenish their hungry horde. That's a huge capital outlay. And lets talk about amortisation. That's at least about half a dozen packs @ $150 ea to power just two modest capability model types, or an outlay of a whopping $900! LiPo's do require recharging, and the don't last forever. Far short of it. On average, even with the best care, there is an attrition rate due mishandling and abuse, crashes which write them off completely, and just plain failure through either malfunction or age. 200 cycles average is imaginatively optimistic in average use as anyone being honest with themselves and capable of simple arithmetic realises in short order. And we haven't even started on the cost of support equipment such as multiple balancers, chargers, leads everywhere cluttering up the place, soldering Deans etc ... AND, let's not even mention the absurdly overpriced ESC w/BEC or OPTO and UBEC per plane for anything worthy of real servos, not required for IC power.

Utter rubbish aka theoretical mumbo jumbo. Better quality fares better, but regardless, bearings fail, glue heat fails, bell housings go out of alignment, magnets come unstuck, circlips fall off, shaft's bend...etc, etc. Theoretically they should last a long time, but practically not only don't they, but what would it matter even if they did? The tech is changing so fast, anything you buy today is pragmatically obsolete within a year or so....if not sooner.

4 per year, if one is fastidious about preventative maintenance changing them every three months regardless of their status. So we're up for $12 per annum to replace glow plugs. Hmmm... Let me see now. That's less tha I'd have to spend on Deans connectors and solder per year with electric. Now if one was to use your 7 years per battery methodology as a cost comparitive analogy, that's be one new glow plug required only every 4 years. :P

Ahhh..you do like to compare peanuts with pumpkins to rationalise a silly perspective don't you? Instead let's compare the fuel flow of a .25 vs comparable electric power which is the comparable battery and motor size previously selected for realistic example, as .40 sized electric is still disproportionatly expensive. Just the cost of those humble minimum few batteries alone buys me an awful lot..lot...lot....lot...lot of fuel, AND, I don't have to explain to the missus why I need to take out a loan for $2000 to spend on 'fuel'. Here's a pic (see below) illustrating the typical e-zealot's bevy of batteries. I think I could buy a small seaside cottage with what's he's spent there.

Oh please,...Stop it. My jaws are aching. That's grasping at such utter irrational absurdity. It's be like me saying it costs to wipe summer bug strikes and dust off electrics. ROTFL.

Err...no they don't. Light's companion is fragility.

And let's not go into all the other limitations of current electric due cost consideration. Affordable in EP means small. Small means rubbish Reynolds numbers and the required weight to accomplish acceptable power to weight ratios carrying a heavy battery means low mass. Both make EP affordable to any economically rational and sane EP flier fly like toys rather than miniature aerplanes.

If you're going to present an argument for electric = superior, try and make it both rational and favourable next time.

B.L.E.

Does anyone really choose electric or glow based on a careful cost/benefit analysis? Trying to convince people who love glow engines that electric is "better" ultimately amounts to.................

tIANci

Wow this thread is coming alive again! Let's put it really straight. EP is EXPENSIVE it will never be cheaper than glow. I have sold all my GP stuff off and am now fully EP and I love it but I have to admit its not cheap for sure. I still find that EP is very affordable when its in the 400 sized motor range, anything more and the cost increases like exponentially.

Anyone who says the lipo will hold 200 cycles is just lying to themselves. Even NiMH batts will not handle 200 cycles that well.

I worked with one of the leading lipo brands and I can tell you this ... the tests carried out for 200/300 cycles are based on 1C or just 2C. On a 20C batt, if you push her at 20C for 50 cycles your will have a 'fading' or degradation of 20%. Now this is with Korean ENERLAND cells. So let's get real ... how many EP guys will not push the batt to around 85% of its discharge capability? Thus 200 cycles is not realistic unless you fly a GWS Slow Stick on a 20C 2,000 mAh pack.

EP will always be expensive. But the fact is its really catching up fast, this is evident from the advertising you see in your RC plane mags. Almost 65% of the ads are for EP ... this is so obvious over the last 6-9 months.

May we let the dead horse RIP?


ps Sigrun - you are very mistaken about the small is bad etc. Trust me the small planes do have very good power to weight ratio, that is the beauty of EP. My small EP planes of 35" - 40" have a power to weight ratio of 2:1.

sigrun

Hi tIANci

Er...no.

Try this and tell me this is "mistaken". The math simply doesn't lie. Apologies for the long hand rather than symbols, but RCU doesn't support easy facilitation of the conventional symbols.

Regardless of whether we're discussing IC or EP, Reynold's number does affect how a model flies, feels and handles. Reynold's number = density/viscosity x velocity x length. Now we can't control density/viscosity, but we can exercise control over velocity and length. So for all practical purposes, Re = kVL. Small Reynolds numbers are bad, or in other words, small is bad. That's simply an undeniable aerodynamic fact nothing to do with whether we like how it is or not or what one might prefer to believe.

Exacerbating that is the fact that small generally also has little mass which doesn't favour momentum or intertial stability. And due to the requirement to carry a battery/s sufficient to accomodate the current and capacity demands of said powerful electric motor, the airframes are extraordinarily light (& relatively fragile) to achieve the required power to weight ratio. On the negative side, as you consume power, unlike liquid fuel, cells's don't lighten as they change state. Boooo! On a positive note, the CG shift with burn-off in IC models is absent in an EP plane.

The Re problem isn't exclusive to EP per se. The problem is that affordable EP is still way too small, upon which we're both agreed. The 40-50 IC class isn't king just because of fuel burn. It happens to conicide with being a compromise of a decent size for reasonable handling (ie: Re), mass, fuel burn, visually accepetable at a safe from dumb thumbs height, fits in the car and at home for easy storage, & most importantly, is economically viable. When EP achieves a similar affordability status, it'll achieve a wider following. Right now its a fad driven by the zeal of a few fanatics and marketing departments seeing the promise of fatter margins achievable on product.

Like your 40" planes, I have a Hyperion YAK 55SP powered by Hyperion Z3007-26, but despite it's excellent performance it still just doesn't fly like my IC 50 sized planes. Cost differential? Putting together a 50 sized IC such as a TT Imagine 50 is still cheaper AND way outperforms the 10e, even without excluding the cost of just a single 3S1800 20C VX lipo which would buy me a LOT of fuel and flying time. And I have six of those to share between my E-sailplane and the YAK, so do the math on that....and you'll see that what those batteries cost would have bought me a lot, lot, lot, lot, lot, lot of glow fuel. And that's before taking into consideration the numerous other larger and more expensive batteries and very expensive speedies I have for my 500 class e-heli, 500 class e-sailplane or 600 class Fun World EP.

As I said in my very first post in this thread, you simply can't argue rationally for EP on economics. With the exception of instances where one might have a clear advantage over the other, largely, it's just a "I prefer..." preference thing. There are aspects I like of both, but I still prefer IC generally.

somegeek

My Feedback: (2)

I agree. To each their own. 'better' is relative.

somegeek

tIANci

Sig - the cost issue is a forgone conclusion ... EP is not cheap at all. As for your explanation I prefer it in writing than in formulas ... hahahahaa ... I agree the Reynolds numbers get better when the craft is larger. I just saw a Comp ARF Extra 2.6M that came in on a dead stick. She was FLOATING!!! Awesome to see ... but what I meant mistaken was when you pushed the issue of:

Small means rubbish Reynolds numbers and the required weight to accomplish acceptable power to weight ratios carrying a heavy battery means low mass

You do mean that to get good power to weight ratio you need to get the plane very very light at that level. Am I correct? Also, let's not talk stability because when you fly your 40" EP planes its about throwing it about. We know what we are getting when we buy small planes. By the same argument your 40% plane is nothing near a full scale but that does not mean we should buy a full scale plane to enjoy the Reynolds numbers. Since our 40 sized planes are very small and now ver bad ...

What is missing in all the equation is the FUN FACTOR ... whatever makes you happy go with it.

stockdaddy

Just a guess but i would assume electrics now make up 80%+ of the 25 scale and lower market though just 10% or less of the 40 scale and higher market. Overall electrics make up over 50% of the market.

With some 5lb+ 40 scale planes costing under $200 to convert to electric power, (electric motor, ESC & lipo) we may soon see a RTF or RR Brushless electric kit hit hitting the market soon for under $300 that yields over a 1 to 1 thrust ratio. That would be a big milestone for electrics.

tIANci

stock - the main barrier is still the price and reliability of lipo batts ... having 50C continous is useless unless you are a pylon freak. We need cheaper and more reliable lipos. Actually, motors and ESCs are super cheap not, I got some for factory direct and its a steal, makes United Hobby look like going to Rodeo Drive for shopping!

I can say that my 80" EP conversion will cost me only USD170 for motor and ESC. The set up will give me an estimated 18-20 lbs thrust. Let's leave batteries out as for a 10S set up that is going to be very painful. I expect to have at least 3 flight packs ... OUCH OUCH OUCH!!!

opjose

Eh, call me crazy, but I did when determining what I wanted to do with a few planes.

I was leaning towards electric, on 3 planes, and due to an analysis I ended up with 2 glow and 1 electric.



Ultimately it's nice to be able to choose:

"Hmm... I don't have much time, I'll grab the electric today"

Versus:

"I'm going out all day, I'll grab the glows...".

Or just bring both along for variety.

opjose

I'd agree with that ratio, however that 50% represents predominance in small scale craft which include Park Flyers, etc.

In the Club Field environment, electrics still remain in the minority. In the Park Flyer arena, you only see electrics.

The Park Flyers in turn take this and pronounce glow "dead".

The Club Field flyers don't understand this assessment.

Jim Thomerson

Keep in the back of your mind that there are megabucks being spent on developing light, powerful, safe, cheap electric power supplies, and a moderate amount being spent on developing smaller, more powerful, lighter, more versatile, etc. electric motors. Budget for improving glow engines for model airplanes is $17.83.

I'm gonna go out and put some more break in time of a Fox stunt 35.

sigrun

Undeniably, affordability is an influencing factor. Often disguised by a cheap easy-sell all-in-one park flying e-package tailored to appeal to the inexperienced and uninformed desire, this leads many neophytes to purchase an unreliable e-rubbish parker-flyer 'with the lot' as their first RC model. The subsequently less than satisfactory e-performance, unreliability and disproportionate cost to effect anything like what they expected is not discovered until after that first mistake.

More to the point, as can be seen in this thread, the cost vs benefit 'analysis' is a point touted by blinkered e-zealots who haven't actually thought it through to justify electric. Kinda' silly really, on two counts. One, when examined rationally, any cost versus benefit breakdown is generally extremely disfavourable to EP. And two, being interested in EP doesn't required justification any more being interested in IC, or photography, or golf. Either you're interested and can afford it.....or you're not and can't.

What so many EP zealots just don't get is this. No-one likes having a dogmatic perspective rammed down their throat day in and day out, especially when they aren't in the slightest interested or vehemently disagree. Not the sharpest at persuasion over to their point of view, that element of "EP is the only way" nutters present in every club tend to be so self-absorbed in their own world, they push that barrow to the point of alienation.

sigrun

The tolerance of park flying and park flyers by the citizenry and 'city fathers' alike has a finite life, a fact as yet unrealised by those to whom it is all "a new experience". Yoda has seen all before. Watch, wait and see.

Not so. Master Yoda suggests many wiser club fliers understand that 'park flyers' are predominantly EP fliers who by and large tend to favour that environment for it's current freedom from enforced regulation or obligation to flit about with unrestricted joy with their newest toy, don't comprehend or understand the inevitible eventuality they will be faced with. And they will want to grow, which will naturally point them to a club with facilites where they can do so. The older, wisened seasoned IC (or EP) club flyer understands that it's much like watching your child and teenager develop through adolescence perceiving everything new they are discovering is being experienced for the very first time in the universe...and it is...by them in their as yet experienced and known 'universe'. [X(]

Phlip

Amen, brother Sigrun, preach it!

All of these pages to argue about a question "Remind me why do we fly glow planes, compare to electric planes," to which most would answer:

"'Cause it's fun!"

Phil

sigrun

No. Untimately there's nothing you can do about small Reynolds other than recognise it and design for it. Light weight is simply another (second) unavoidable coincident factor which exacerbates that toy like handling characteristic because the models have low mass and low (relative) speed. Subsequently their penetration and inertia in the same air (resistance to wind, gust thermal and other mechanical turbulence) is significantly less favourable than larger, heavier, faster models all else being equal (eg: wing loadings).

The argument you present trying to rationalise a case for small lightweight same cost EP (eg typical 10e versus the typical .46 or .60 sized IC just doesn't hold up because of Reynolds. Whilst agreed that a .46 sized model hasn't the aerodynamic characteristics of a typical 33% or 50% scale or full sized aircraft, the influence of Reynolds numbers upon flight in the fluid in which we operate doesn't favour minuscule, and that is abundantly clear to anyone who has operated both a .46 class model of and a .10 class model. An IC .46 sized model simply does fly so much better presenting a much more favourable and generally acceptable cost effective compromise.

Even where you have both of the same class, EP still flies differenty. By way of example, compare the performance of a [link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=240]Modeltech Magic Extra 300L[/link] and a [link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=372]Fun World EP[/link]. Whilst admittedly both are similarly sized with advantage of slightly larger going to the IC Magic Extra, the performance difference is huge and handling quite different. There are videos of both at those respective links for you to view and assess their relative flight performances. I have a TT .46 in my Magic, and because of the characteristics of the Magic and props fitted where the Magnum .52 is not using it's timing and capacity to max advantage plus the huge excess power versus power required availablity even from the TT .46, the performance of the Magic between the .46TT and .52 Magnum is indistinguisable in that video and effectively moot. The Magic comes in at just over the 2KG mark whereas the Fun World tips the scales at around the 1.5KG. I have both models and though they are very similar, they are quite different to fly even though the EP is about a .35 sized IC equivalent. it would be interesting to fly andf directly compare Magic Extra 300L's one of which was converted to equivalent EP. It's a model which would be well suited to EP conversion, though why would you when the purpose designed Fun World EP and similar are widely available and very affordable.

What it all boils down to is that it is a simply inescapable fact that small sucks when it comes to model aeroplanes, and small and light EP sucks especially. Tiny EP is a 'choice' more often than not constrained or 'determined' if you will by economic sanity. That is changing, albeit very slowly. such that in 2007 a .25e is still disproportionately expensive to set up and operate in comparison with IC. And anything 40e that you'd want to fly - ie: let's forget silly trainer conversions - almost requires a second mortgage.

I agree entirely. Personally, I generally find small, IC or electric, tedious, although I'm sure that as a 10 year old, I would have lusted after a Park Zone FW-190 or P-51 displayed on the toy shop shelf, considering the promise illustrated by its box art and war paint irresistably appealing.

opjose

"But that's impossible."


"Because you do not believe."
-Yoda.


Not only does it have a finite life, but the intolerance is exacerbated by those who too often rush in w/o first patiently checking the waters.

sigrun

Far from being agin' EP, I'm all for it, but driven by a perspective with balance.

The feeder for R/C in years past was C/L aka U/C. Although those still practicising U/C - C/L are wont to wish it weren't so and in obstinate cases even stupidly deny it, control-line has as much strategic importance and presence in 2007 as a steam driven dreadnought, or future as the SS Titanic in our super-airliner age of cheap fares and fast inter-continental travel. I say that as one who was in my own youth a control-liner, and who occasionally still dabbles, enjoyably, in the pleasure of twisting the lines. But expecting today's generation to be excited by it? May as well ask 'em to walk to the local supermarket and carry home raw ingredients to make and cook their own burgers 'n fries instead of being driven to the local drive-thru and slappin' down $10 for a McMeal in a box with a toy. <sigh>

Traditionally, for a multitude of reasons, IC R/C has been predominently the realm of middle aged to older person. Except for the club Mini-Me brats, one rarely sees juniors in IC R/C as were ever present in C/L. No longer tantalised by any perception of romance in aviation or seeing it as particularly adventurous, techologically sophisticated, unusual, new or exciting, EP for whatever reason HAS captured the attention of a new generation drawn to things perceived as 'powned' by their generation and techno "coooool". Hence why heli, and particularly e-heli is so "cool" and popular. For all of us in R/C, ultimately, over time, EP introducing another generation to the world of model flight will prove to be a good thing.

Whilst a personal preference for one over the other is perfectly natural and fine, what needs constant correction are silly, polarised, elitist self-rationalisation and zealot driven EP vs IC attitudes distorting the facts to serve personal prejudices, bias and agenda. All they achieve is to alientate and divide the wider R/C community, and that's good for none of us.

One thing's for sure, EP can only keep getting better and cheaper, thus more attractive in many ways including cost, whereas IC model engine development has stagnated for many years and sadly, has probably already achieved the epitome of its commercially motivated/viable technical development and minimum sustainable pricepoint.

buzzard bait

So small models "suck"? Well, here goes. I had a Sig Moncoupe powered by a CO2 motor. It had a 24 inch span, weighed 2 oz and it was beautiful, if I may say so. And it flew more realistically than most RC scale models that I have seen over the past 40 years. Vic Smeed, in his book on free flight scale, makes a similar observation about the diesel powered models he competed with--they looked more realistic in flight than most RC scale models. They are no more "toy like" than a quarter scale model that weighs maybe 20 lbs. Neither the quarter scaler nor the CO2 model look very good in any substantial wind, where scale models are concerned. Full scale light planes start at around half a ton. Of course, it's not because those FF are small that they fly so well--it's because the builders put a premium on realistic flight. You rarely see this with RC models, even in scale competiton.

Sport models are a different matter--whatever style you like is good, and that goes for small lightweights as much as ballistic pattern models.

Even sea gulls are small compared to a .46 powered model, yet despite the Reynolds numbers, they seem to fly pretty well.

I love IC engines and have done very little with electrics, but I like the fact that electrics broke the mold for construction and showed some people how to build light again.

Small planes have to be built lighter for their size to fly well, but that is not hard to do, and it doesn't make them fragile. Weight increases as the cube of size, but strength only as the square. That's why ants have skinny legs but can fall off a table without getting hurt, while elephants have thick legs. My experience is that, properly built, small, light planes suffer less crash damage than heavier models. I also find the small ones tend to suffer less hanger rash, at least at my place.

I like big and I like small. My IC engines are .03 to .91 cu in; my two electrics are small. To anyone but perhaps us, they are ALL toys no matter what size they are.

Jim

B.L.E.

Yes, if small sucks so bad for flying, why then is the ability to fly limited to mostly to the world's tinyest creatures. Insects, birds, and bats are for the most part tiny. I have built a few 1/2A glow planes and for the most part, was surprised at how terrible they are not.

Some people use the word "toy" as if it was a bad thing.

sigrun

Acually it's Reynold's number (singular), of which curiosity begs the question, apart from stupidity and irrelevance, what else was that analogy specifically intended to illustrate?

That you love small models and felt bound to retaliate for an offended sensitivity? That's fine, but unfortunately no matter what you like or prefer to believe (perception) doesn't alter a physical reality, ....only your own.

Really? Give a big (or little) 'kid' a park foamie and let him flit about with it. In between bumping into everything possible within sight which the greater percentile of the time will be terra firma, which he'll consider a 'landing', he'll be 'flying' it - well keeping it aloft more than less in a manner of speaking - within half an hour. Now give him a 4 channel .46 class IC powered RC model that does circa 80mph and take along a garbage bag to help him collect the 'consequence' of his first unassisted 'landing'. If you've been observant, you might now be able to distinguish the difference between a "model aeroplane" demanding the acquisition of a prerequisite skillset to operate responsibly and safely, and a toy for the trite amusement of those unable to comprehend that distinction much to the bemusement of those of us who can. [sm=regular_smile.gif]