Ghost I stand corrected, thank you. I do know for a fact that that prop is very popular with the fun fly guys. It works well in that application. And as I said it will work well here too.

Mark Shuman

sigrun, you have been so busy trying to launch a personal attack you have missed my point entirely. It is a simple fact that horsepower figures are a poor way to compare engines. To simply suggest that engine A is better than engine B because of a slightly higher HP figure is shortsighted at best.

The best way to compare engines is through torque figures and more specifically torque curves measured on a dynometer. Unfortunatly, this information isn't available to us. RPM figures are another attempt to make an "empiricial" comparison which in the end only tells us how fast an engine will turn a given prop on a test stand. No knowledge is gained in how well the engine will perform with that prop in the air. Of course if your goal is to fly your test stand then it could be quite helpful.

Another simple attempt to compare engines as well as props has been in the form of thrust measurments. This goes a step further than the RPM number from the test stand because it roughly tells us how much air is being moved by a given prop/engine combination. Again, this only indicates the peak output of that combination while telling us nothing about where in the RPM band usable power is being developed.

The fact is two stroke engines rarely operate at their peak RPM (where that HP measurment is taken) while pulling your airplane around the sky. If they did I would agree with your comparison of HP figures wholeheartedly. I've never seen anyone manage to take a plane up and keep it in a dive for the whole flight - it might be possible for half a flight that ends in a crash but then what fun would that be! [:@]

Now consider what I have just said and apply that to what we know about four-stroke engines. If you make a simple comparison of HP figures for a given displacement the two stroke would win every time! Granted, a larger displacement is required in a four-stroke to move the same plane as a two stroke but if you follow the general RC rule of using a higher displacement four-stroke engine and manage to match the HP output precisely (yes I realize that is impossible in all practicality) between the two stroke and four stroke then the four stroker would be the winner because of where in the power band the power is being made.

The TT .46 may share its roots in the OS .46 SF engine but that doesn't make it an SF. It is still a completely different engine. The same goes for the FX and AX. That is the comparison I was making earlier while talking about these two engines. If you simply look at the numbers they may as well be the same engine. Real-world experience has proven that not to be the case. That is why I stand behind my original post.

By the way, if you go back and reread my first response to your post it is quite obvious my point was that your experience (if any) with a TT .46 Pro is not up to the standard of this engine. I wasn't laying any blame on you as I did say maybe the engine was a lemon. Heck it could have been somebody else's engine which they tuned wrong. The first attack was made by you in your first response to my post. You accuse me of attacking the messenger when in fact it was you who did that very thing. You went on to say you are right because of "the undeniable empiricial evidence" and yet the only hard facts you have provided in all those words you typed are horsepower numbers that are only occasionally reached in real-world flight. I have just given you a full explanation as to why your theory falls short of reality. The simple fact is these engines are much closer in power than you are willing to admit. I say this based on my own personal experience and that of many others at local clubs and on these very forums. I have flown both these engines so I am speaking from first-hand experinece. Is one a little more powerful than the other? Undoubtedly yes. But they are much closer than you seem to want to admit. Why it is so hard for you to acknowledge that someone else may have had a slightly different experience than you is beyond me. I guess it is just easier to go on the attack and try to sound educated then have an intellectual discussion.

My pride has been quite happily intact all along, thank you. But thanks for asking.

Mark,
Sorry about that.[] I use the 12.25-3.75 on a OS 46FX in a 3D fun flyer myself. Exceptional prop for that use. Just my thoughts.

Cheers.

I fly the LT-40 with the TT46-Pro. I started flying this past spring with the LHS recommended Master Airscrew 11-4. Plane flew fine but engine screamed (It sounded real cool with the prop tips going supersonic!) and experienced guys would invariably recommend different props every time I flew. Last night I changed to APC 11-5 and even this total rookie could see, feel, and hear that this was a much better fit for this setup. Ran alot cooler.

I thiunk the, OS is a lot? more poiwerfull thasn the TT bewcasee when I diiid a scintific excp[erimnent where I stuck my finhgers in; the OS's prop[ i8t cut throth two clean and when I stuck them in the TT's prop it only cut thru one clean and one halfway.

zAnd yes I did use the other hand I'm no dummy. hjard to tyupe ewith banmdahes on..

Andy

Hi Steve,

I started out with an 11X5. It gave me good pulling power and slowed the plane well for landing. As I progressed (currently have 27 flights on the LT-40) I moved to an 11X6 then to a 10X6 3 blade. I found the 3 blade to pull the thing like a tractor for takeoff (as did the 11X6 but the 11X6 did tend to keep the landing speed higher than I like) and basic aerobatics (loops, rolls, Immelmanns, Split "S",s and the odd Cuban 8) and still allowed it to slow down well for landing.

Of course it all boils down to what you are comfortable with. I also changed the music wire landing gear to Dubro part number DUB789
for the main gear and the nose gear to Fults Tooling dual strut nose gear part number FULRF350. With this setup I got a plane that now gives me 2 inches more ground clearance and can land smooth as silk.

Just my $.02 worth

Bill

There has been a lot of highly entertaining blather here, but the simple fact is that the 11-6 will work very well with the combo in question -- so will an 11-5 -- & so will a 12-4. An 11-4 will also work well, but at the cost of slightly accelerated engine wear relative to the other combos.

I have done many side-by-side comparisons of engines, & regardless of stated HP figures, a TT .46 Pro easily matches an OS .46 FX and often out powers it somewhat -- on the bench or in flight. It also can match the new OS .46 AX (which is barely more powerful than the FX, despit OS claims to the contrary). Additionally, the TT .46 Pro is actually more similar to the FX than the SF (having the same designer as both the OS engines) while being somewhat different in detail from either. It is also manufactured to ISO 9001 Standards, which the OS engines are not.

I fly OS, TT, MECOA & LEO engines -- all have the same design roots. The TT's are by far my favorite, in real world use.

I have read most of the post concerning prop size and all of the poster have neglected to realize that prop clearence is the driving factor in this airplane. Using the assumption that this is a typical trike gear trainer style model most 11" and 12" diameter props are ill suited for ground clearence. I would recommend a 10x6W for this airframe.

FYI- ISO 9001 is not a manufacturing standard and in no way assures quality product. ISO is more of a quality procedures documentation standard in which the manufacturing paper trail and written quality procedure is documented. You can be an ISO manufacturer and build crappy parts. ISO just means you build crappy parts the same way with same documented quality procedure every time. Manufacturers also have to pay ISO to become ISO (big $$). There are many world class, top notch, manufacturers out there who don't have, and don't need, ISO certification to know they are the best at what they do.

(this has nothing to do with model aircraft)

In my post I did mention that I changed the main and nose gear to go with the larger prop diameter. I did fail to mention that you will need to do this for the ground clearance or you had better never land hard as the music wire will give and then instant prop strike (Ask me how I know).

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.

Ghost, no problem. If I am wrong I will admit it and am glad to learn. You done good, and thanks again for setting me straight.

Mark Shuman

Speaking of which yours is definitive blather.

In contradiction of the accepted status quo by both TT & OS and countless users, your opine is proffered entirely without substantiation.

As such, whilst it may be comforting to you, but nevertheless renders = false until evidence to the contrary can be presented.

flycatch you bring up a pertinent point here, though in the specific case of the LT-40 with stock wheels and gear, it will accomodate an 11" and even 11½" blade without issue on grass or bitumen. If it's striking, the default gear just needs to be bent back into its original position occasionally, as it tends to spread with consecutive impact or heavy landing lowering prop clearance in continuous use.

Wow sigrun, congrats! Finally a post that isn't so full of attempted insults that I can actually agree with some of your points. Of course not all - but we do all have our own opinions don't we.

First of all, may we agree to disagree. You have your opinion on how close these two engines are as do I. Just reading our posts will easily point out that they are like oil and water. If we went out and asked for a third opinion it may be very well different than that which we have already expressed through an overabundance of words.

Second, in your most recent response it appears that you are under the impression that my optimum prop suggestion in reply to the original post was an 11 x 7. Here is a quote from my original post.

"Back when I was still flying my LT-40 I tried an 11x7 APC and it pulled it without any problem. The sweet spot I'd say would be an 11x5 or 11x6".

If you were you under this false impression all along I can understand why you would be so definsive of the pulling power of the OS in relation to the TT. I never made any of my prior statements with this in mind so if you had I can see why you would believe some of my statement to be exaggerated. As it turns out our suggestions are roughly equivalent. You said you like the 11x5.5 and I said the 11x5 or 11x6.

You got me laughing on this one... You have yet to offer up a concise post. Why change your ways now.

As far as the quoting all I can offer is that I was short on time and wasn't able to give my response as much attention as I should have. The tools here on RCU make it all to easy to include the entire original post which was already too long. I was responding late at night while waiting up for my wife so I could take her to the hospital. We just had our third child yesterday.

The generalizations started whey you listed three engines in relation to the TT Pro. You later went on to mention the OS .50 and yet jumped on my case when I mentioned the TT .40 Pro. With all due respect sigrun, you have quoted my posts then used them out of context just the same as you have accused me.

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

Hmmm... You have just quoted my statement on comparing HP figures and called it utter nonsense. Then you go on to agree with the very point I was trying to make in the following statement.

You so enthusiastically eluded to "the undeniable empiricial evidence" in your post and yet the only hard facts you offered were HP figures. You eluded to some statements made by TT but I have yet to see any evidence or even a description. sigrun, what evidence were you referring to, might I ask?

I agree. That is why we so often look to personal experience when trying to make comparisons between competing products - engines or otherwise. Considering the statement you just made about manufacturers numbers being exaggerated I can only assume you agree that sometimes personal experience is our best measure of one product against another. In this case our experiences are obviously different. Hence, our differing opinions.

I agree.

I agree with both point (i) and partially with point (ii). On point (ii), just as you stated earlier, these numbers are at times exaggerated. When and to what extent we never really know. Personally I put more weight in personal experience than numbers often provided by a marketing department. Especially when they don't appear to agree on some basic level. This, of course, is a matter of personal opinion. When it comes time to spend the money, it is up to the person holding the wallet who gets to decide which is more important.

The key term here being "potential." How often do we see someone posting on this site DON'T BUY XYZ ENGINE, ETC. after being disappointed in the performance, quality or any number of other "human" measurments that we base our satisfaction on. It is human nature (and just plain smart) to try and learn from others experience before spending hard-earned cash. Unfortunately, this is only accurate part of the time and isn't much better than trusting that the manufacturers have told us the truth.

Ok, now you are putting words into my mouth. The point I was making was that they don't provide a complete picture from which a fully informed decision can be made. To use the manufactures numbers alone is to put your trust in the word of the manufacturer - as you eluded to, it can be a hit or miss proposition. I never called tach results meaningless. They are, however, still only a piece of the overall, incomplete puzzle. Yes, alone, it is a good indicator of propeller performance when comparing one prop against another and a good way to find a starting point. This still must be followed up by real flight time to fine-tune the final prop selection. A stationary bench test is in no way able to account for all the variables associated with real flight. The least of which is the fact that the chosen propeller in flight is constantly in forward motion - a fact that is difficult at best to account for while testing propellars on the ground. I agree the topic requires a thread of its own to even begin to cover the subject properly. I also agree that many modelers would benefit from using a tach of their own and learning at least the basic knowledge needed to select a proper prop instead of always asking "which prop is best?"

I agree, see my earlier statement about my recommended prop size. I never said nor implied that an 11x7 is the ideal prop for this engine/airframe combination.

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.
[/quote]

See my original post for my comment on running an 11x4.

We know this to be true at 16,000 RPM if the numbers provided by the manufacturers are truly factual.

Your statement, however, true in one instance (at 16,000 RPM,) makes no mention of the rest of the RPM range where the engine spends the vast majority of its time in service. We can blindly assume that a given engine has a linear torque curve but this is rarely, if ever, the case. In fact, this very curve will very often have multiple "peaks" that are spread throughout the RPM range. This is especially true when considering two-stroke engines. For this reason the TT .46 may be making more power than the OS .46 at say 7,000 RPM while the OS may be making more power at 8,500. The key word here being "may" because we simply don't know.

Add personal experience to this and we are all open to our own interpretations which in this case has shown its own variations. I won't go so far as to say the TT is more powerful than the OS but my own experience hasn't proven that to be false either. What I have observed is these two engines are very close. Without a more elaborate comparison where an attempt is made to account for all the variables it is impossible to know for sure what these engines are doing outside of the 16,000 peak number we are given and can only assume to be factual in the case of both manufacturers. It is, after all, entirely possible that both manufacturers have exaggerated their numbers.


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.
[/quote]

I have yet to see OS share the torque curves on either of these engines. Have you seen them published somewhere? I would be very interested in seeing their results.


Again, I'm not sure where you were led astray in relation to my prop recommendation on this plane. I agree with your suggestion being right in the ballpark.

I'm curious about what you mentioned about the price difference between the TT and OS. Here in the states it is currently about $25.00 US and it was a little more when I purchased my first one. I did consider buying an FX when they were being phased out since the prices had come down with the new AX out. But I simply didn't need another .46 size engine at the time so I passed on the opportunity.

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.
[/quote]

You gave me reasons why you disagree with my claims - some had merit while others didn't. It only makes sense sense for me to ask you to back up yours.

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.
[/quote]

Again, see my comment on the 11 x 7 above.

Me2. Nah..Nahh...
[/quote]

All those big words and you never came out and said what kind of personal experience you actually have with the TT. I was fishing when I asked that question. Thanks for taking a bite.

Finally.
[/quote]

But which one and at what RPM! As I said earlier I agree to disagree.

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.
[/quote]

OK, since we are comparing credentials, I have degrees in both English and Journalism and I am an admitted techie since I currently work as a computer programmer which is where I have focused at the graduate level. I have to admit I find your use of the English language very intriguing. You definitely like using big words. In places it comes across as if you are simply trying to look authoritative because your grammar skills don't always seem to match. I don't mean that as a put-down, just an observation that came to mind while reading your posts. I didn't mention it, though, for a few reasons. First it is irrelivent to the topic. Second, I noticed you are from Australia. With all the dialects that exist around this planet of ours what I noticed as quirks in your language could be perfectly normal "down under" where you live. Third (I know, finally...) people typicall use language in forums that isn't up to their normal writing standards when on the Web.

Too bad we can't have some kind of "fly off" I'm sure it would be quite entertaining. A guy in my club is currently building a H9 Twist powered by a .46 FX which is the same plane I have my TT on. I am anxiously awaiting its arrival at the field so I can see a good one-on-one comparison.

Thats got to be the longest single post ever....[X(]
Anybody read it?

St
Steve, my standard answer-copy to your computer, or print it out for your shop.

NO!

That's just has to be an attempt at the shortest!

Thanks jettstarblue... Very handy.

No problem.

Never thought this post would get this many responses. Still think the 11X5 is the way to go. I'll buy an 11X6 also and see how that goes also. Ground clearance may be an issue, but I usually only prop strike the aircraft on really bad landings, so I'll give it a try.

Just an FYI and this will probably start another prop war but oh well.

On my LT-40, I have replaced the main gear with the Dubro Figerlass gear and the nose gear with the Fults dual strut model. This gave me another 3 inches of prop clearance.

Today, our club had it's Fun Fly and just for giggles I had several 12.25X3.75 APC 3D props ready so I screwed one onto the OS46AX in my LT-40 and all I can say is boy did this wake that plane up. Plus with the different main and nose gear I still had 3/4 inch of prop clearnace.

Oh and just so you know the engine is still brand new and only has 8 flights on it after today and it is still in the process of being leaned out from breakin settings. The plane has had all of the control surfaces sealed on the underside which also made large handling improvements before the prop was changed

Please understand these are not exact measurements by any stretch on the imagination but just generalized comparisons.[sm=wink.gif]

Intial prop was an 11x5, now it has the APC prop.

1. Shortened taken run by at least half the distance.
2. After the plane broke free of the ground I was able to pull vertical for what looked like about 500 feet until the airframe finally overloaded the prop and the plane slipped into a power on stall.
3. All maneuvers (slow rolls, rolls, loops, cubans, immellmanns, Split S, reverse cubans and inverted flight) improved the wow factor quite a bit.
4. Level flight at full power on a timed 300 foot run improved by 4 - 5 seconds.

Yes, I may be overpowering the airframe but with smart throttle management, this should not be much of a problem.

All I can say is WOW [X(]...what a difference in performance.

Rant over....

fstevenj, the LT-40 is a great candidate for a taildragger conversion. This all but ends any problems you have with this plane and prop clearance. The stock nose gear tends to compress (especially on grass) during takeoff that puts the plane in a nose-down attitude during takeoff that results in more drag on the wing and, ultimately, rather long take off distances. If you don't feel ready for the conversion yet I suggest adjusting the nose wheel up as high as you can. If I recall correctly I did this with mine but still could have used a little more height. I finally got tired of it and did the conversion. I haven't regretted making the change one bit.

Doing the conversion really livens up this plane since there is a lot less drag without the nose wheel. Initially, landings will be a little hotter until you get used to it. When I converted mine I wondered to myself why I hadn't done it sooner. It really improves the looks of the plane too.

I can share some pictures of mine if you are interested.

I used the DuBro gear on my conversion as well. It really tracks well since it has some give to it and I've managed to test its strength a couple of times and, even in the cold, it just springs back to shape and comes back for more.