FlyerBry

I'll attempt to keep this as relevant as accurate reply allows. I would have preferred concise, but recognising what is achievable in dialogue with you won't attempt the impossible.

However first a humble request? If you must quote, could you do so with relevance? Top posting followed by quoting the preceding post entire is superfluous. The reader doesn't need the entire preceding post quoted when it can easily be otherwise referred to.

First let's divorce the discussion of stupidly simplistic and inaccurate misinterpretive generalisations reinvented in each succeeding post by you such as "engine A is better than engine B". I never said nor claimed any such thing. You have yet again diverted the discussion into an irrelevant point of debate which was never a statement attributable to or claim made by me or in fact ever in contest. Just comprehend what was said, not what you prefer to imagine was claimed.

All that was ever originally said by me in response to your claims of the TT46Pro's power output vs that of OS' 46FX was that the claim = false (paraphrased). Nothing more was implied about engine superiority otherwise any more than I disparaged the SF or Pro other than pointing out their lower peak power outputs and design heredity both of which are supported by statements from their respective manufacturers as fact and omnipresence in the public domain as common knowledge

As for quote: "horsepower figures being a poor way to compare engines being a "simple fact", this equally is an utter nonsense, both contextually and technically. Whilst acknowledging each manufacturer's quoted figures (usually DIN ps) figures are but one datum, uniformly exaggerated and previously mentioned specifically as such, in the absence of other independent and objective testing under controlled conditions they are the only quantitive datum to which most R/Cers have uniform access. That to exaggerate that the are the whole picture is yet another example of you reading things into what wasn't said in an apparent enthusiastically biased argument. One never suggested that they shouldn't be interpreted contextually in conjunction with other objectively reliable data, which includes empirical testing by those with a clue. Sadly, this condition excludes the 'anecdotal evidence' of > 90% of the R/C community.

All leading manufacturers who are intent upon competing for market share in the increasingly cut-throat US market for a slice of the R/C consumer pie exaggerate their figures. They do this to sell engines into that status conscious and competitive male dominated R/C market where a rampant consumerism indivisible from a material society consciousness abounds. Couple this with a 'culture' where "koOl faKtA rulz" and an abundant ignorance prevails of anything truly meaningful in quantitive or technical terms ensures only engine 'dick size' aka peak power claims count. The sales success of O.S' premium price'n pitched 50SX amply illustrate this phenomena. This is the paramount reason today that engine longevity doesn't mean ****, and invariably 95% of single cylinder R/C 2 aircraft stroke engine design today is Schnuerle ported, over-square and highly timed to produce an impressive quotable ps figure near or at the top of the sustainable, without premature demise or failure, rpm curve. Where that peak power is developed is only looked at let alone understood by a relative handful of R/Cers, and those of us who do understand don't fall into their target market of said easily duped rampant consumers.

However the two important caveats are, (i) that the figures are quoted by manufacturers and subject to the public domain. They have much to lose in the being unable to substantiate them if challenged by a competitor, and; (ii) in the absence of other objective obtained quantitive results such as measurement by brake dynometer under controlled conditions by an independent credible source, they're far more reliable and accurate datum upon which to base comparitive power outputs than the aforesaid technically ignorant average R/Cers' anecdotal 'evidence'.

As such the quoted figures are therefore of great assistance in this regard, and can generally be relied upon as a predictor of comparitive potential peak power output. That 'common sense' which is the domain of accumulated knowledge dictates that a technical understanding of how engine design influences power characteristics is necessary to be cogent of the contextual picture particularly regarding the usable power curve, and even this needs to be coupled with objective empirical testing to offer a truly accurate comparitive result.

Understanding this clearly implies that taching RPM figures under a uniform controlled condition using standard propellor/s (a measure of load and an ersatz brake dynometer in qualitative simple form), etc does offer meaningful data other than ammunition for a failed attempt at ridicule of the pragmatic methodology by you. The selection of an eventual optimum propellor suitable to engine curves considering the compromise of a particular model's flight envelope and intended role is a totally separate issue and quite complex discussion. Ideally this should of course be taken into account by all when purchasing an engine, but through human falliability is invariably ignored by the mainstream in their technical ignorance and that predictably prioritised quest of acquiring maximum 'dick size' status points required for peer approval powered by the ego's craving for recognition.

Your statement that tach results or manufacturer provided figures are meaningless in predicting usable power is fallacy.

RPM tach results obtained and compared on even simple (air) brake dynometer (ie: propellor) tested over a range of sizing for comparative usable results, or single sized in the 'band' for engine testing, will provide meaningful empirical results to the end user about relative power, torque and power curves. However with basic intelligence assisted by modicum of knowledge aided by experience, one doesn't even have to do this as its already evident from the manufacturer's quoted peak power, practical operating rpm range and rpm at which peak power is achieved where the power and torque curves will lie. Couple this with a knowledge of engine design virtually inscribes curve prediction in stone and informs the erudite whether an engine is suited and if so, which propellor size will be optimum for obtaining (i) peak power and/or (ii) application usually associated withthe airframe drag curve or resolution of the balance of forces where vertical or sustained high g is involved. With the timing of today's Schnuerled engines and a wide variance of operating envelopes, these two curves seldom coincide and propellor selection is more frequently than not a compromise to an airframe mismarried with an inappropriate engine by the uninformed.

Marrying prop with engine and airframe is an entirely separate and complex theoretical discourse, which I shalln't take further here than to comment thus. Whilst the 46's mentioned will happily throw an 11x7 at impressive RPM, that prop size is entirely unsuitable for the flight envelope of the combo about which the inquiry was made. That you recommend such a sizing and suggest not only that it pulls the combo otherwise implies to me that either you were have never flown an LT-40 with an 11x7, but more have but fail to perceive the inefficiency which by implication infers you have no true appreciation of the interactive dynamics involved. Once accelerated to cruise, an 11x7 will haul the LT airframe even though operating inefficiently well below the engine's torque and power curves, but by way of analogy it's like using 5th in a 1.8litre twin cam to drive a loaded MPV up - or down - a hill. The acceleration (and flight idle approach braking) on that pitch with that airframe is absolutely ****ful, no matter which of those .46s the preferred powerplant.

Which is precisely what my recommendation for an 11x5.5 was all about. I can't be bothered elaborating further upon this here. At this juncture either you understand or you don't.

They will iff the engine is (i) propped appropriately, and; (ii) propellor is suited to the model design and its intended flight envelope. Problem is too so many R/Cers choose the proverbial shotgun to go long range varmint shooting or a .222 hornet to hunt elephant. That they don't is purely down to human error born of ignorance, a pertinent illustration of that specific point being equipping a .46 powered LT-40 with other than an 11x5 or 11.5x5. The fact that people ignorantly prop their engines outside their optimum torque and power curves or taking into account airframe drag and operating environment (role) has nothing to do with an engine's inherent ability to achieve them nor reflects accurately upon their achievable peak power output. You are clouding the issue with irrelevencies to the inital and only point of contention which from which you kick-off in constant digression fumbling in a presumed attempt to somehow make your claim = true or even somehow relevant. I reiterate that the OS FX is more powerful than the TT .46Pro. This is neither bad nor good, it is just a undeniable statement of fact admitted as such by the manufacturers repective claims of achievable peak power outputs. It therefore = true. There exists no further point from which you can logically argue which will to alter that quantitively conclusive evidence.

Suggest you re-examine the internals of both examples to which you refer. Except for origin of manufacture or model nomeclature, they are so similar they are far from being "completely different engines" from an operational perspective which is clearly what was implied. Small mods to the piston skirt or other irrelevancies which affect only aesthetic appearance for the purpose of marketing NEW(ness) (assumed = better) or production cost ergonomics such as the substituion of 4 head screws instead of 6. In terms of stroke & bore, timing, practical operating rpm bands, torque and power curves, potential peak power et all, they are per previously quoted comparison respectively so similiar that the only false implication is afforded by (parahprasing you) "they are completely different engines". In fact, OS marketing exploits the AX's similiarity to and FX heritage cleverly pointing out the association as a positive. The quoted ps and operating rpm curves confirm it.

There are several in operation at the two clubs at which I fly and in which I have taken a keen interest. I am most impressed by it, but not sufficiently to favour it over either Enya or OS given the marginal price differential. That it is impressive doesn't alter the fact that like the SF, whilst it is timed such that its power and torque curves offer gumby friendlness, it does have a lower peak ps/bhp output than OS' FX period. Achieving that optimum is up to the end user knowing how to prop the engine and model. Evidence abounds here of the ineptitude of people to achieve that. For someone who would favour or even suggest an 11x7 be used on an LT-40 powered by any of these engines speaks volumes of why you prefer the TT. I have no contest with your personal predeliction.

I wish you were local so we could just do a show 'n tell type put up or shut up demo. Let me save you from the pitfall of further miscomprehension. As a little research will amply illustrate (& my personal experience supports) the consensus of empirical evidence is supportive of the respective engines specs., and as such is undeniable by any reasoning person.

Not at all. You've presented a load of irrelevant nonsense as to why you have come to the false conclusion that the Pro is the power equal of the FX based upon your experience by propping your Pro as inefficiently as others similarly operating FX's outside the optimum performance curves. This result of human ineptitude which has the potential to afflict an FX in terms of robbing it of potential power more so than the more conservtively timed and flexible Pro, you comfortingly label innaccurately as "real world performance". FWIW I live with aviation's real world realities everyday, waiting for the refueller, hoping bags held up by security won't miss me my slot and other considerations divorced from theoretical ideal. However once roling down the runway the theory and math stand up, compromised only by human ineptitude at manipulating the FMS, the forces of nature and the toll wear and tear extracts from engine & airframe performance.

Me2. Nah..Nahh...

Finally.

Er..try to sound educated? Oh dear! If it wasn't your insecurity instead of mine, you'll have me quoting all those impressive credentials in a sig. An adequate command of language is not only necessary but enhances the ability to communicate & comprehend complex concepts which is a prerequisite of erudite exchange. Technical prowess assists greatly as well. In my own case, I have ample of these attributes. That you should imply otherwise reflects poorly upon you and your ability to present reasoned argument.