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lt-40 prop
What is the best prop for a LT40 with TT .46?
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RE: lt-40 prop
I fly my LT-40 TT.46pro with an 11X4.
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RE: lt-40 prop
ORIGINAL: fstevenj What is the best prop for a LT40 with TT .46? |
RE: lt-40 prop
11-6 apc is a good place to start. 12-5 and 12.5-3.75 is also a good choice. Will give you lots of pulling power and not a lot of speed. Just what your trainer needs. Good luck.
Mark Shuman |
RE: lt-40 prop
ORIGINAL: phread59 11-6 apc is a good place to start. 12-5 and 12.5-3.75 is also a good choice. Will give you lots of pulling power and not a lot of speed. Just what your trainer needs. Good luck. Mark Shuman Airframe drag of the LT-40, always relatively high, worsens expotentially as speed increases. ie: V². Thus both by design intention and the limitation imposed by aerodynamic laws upon its optimum operating envelope is to remain in the low speed flight regime to be efficient. Because of that due its its size, aerofoil and consequential parasite or form and induced drag inter-relationship, it requires a lowish pitch prop for propellor and flight envelope efficiency. Engine, airframe and propellor acceleration are inter-related. Thus small diameter or high pitch props, the combination of the two being the worst, are inefficient in the LT-40 scenario proposed. Too small a diameter doesn't produce enough accelerative thrust because of slippage losses failing to accelerate that small mass of fair to sufficiently high a speed vs airframe weight & drag. Similarly the consequence of using too large a diameter where the prop again becomes innefficient through its inability to accelerate the now larger mass of air against the drag of the airframe without loss again resulting in slippage and prop inefficiency. Increasing pitch in conjunction with the lower RPM imposition of the increased blade diameter similarly exacerbates this effect as it did with the too small a diameter. Exacerbating it further with a highly timed 2 stroke like the TT46, you're loading it below its optimum torque and power curves resulting in totally porked acceleration and power delivery. Now putting that into perspective here, a 12x6 is a big ask of a .46 at any time, and for this combo, if you'll pardon me saying so, unwise. Or translating that into non-techno speak, "pulling power" is exactly what it won't deliver. A 12x4 narrow blade might just work, but the optimum efficiency for the combo is undoubtedly sized between an 11x5 and 11.5 x 5. Propellor brand doesn't matter, though APC and Bolly Sportsman props are both efficient though broader blade designs. Now the TT46 is a good engine, but with only about the equivalent power of the long since superceded OS 46SF. An OS 46FX, AX or Enya CX45 it ain't, and even they'd be bogged down by the sizing suggestions you've recommended. With a 12x6 will it fly? Yes. Will it fly well? No. |
RE: lt-40 prop
In other words go with a 11x5 [8D]
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RE: lt-40 prop
You might try a 11X4 for starters but the 11X5 should be a good one to,just try both.
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RE: lt-40 prop
You must be ejikated.
ORIGINAL: sigrun ORIGINAL: phread59 11-6 apc is a good place to start. 12-5 and 12.5-3.75 is also a good choice. Will give you lots of pulling power and not a lot of speed. Just what your trainer needs. Good luck. Mark Shuman Airframe drag of the LT-40, always relatively high, worsens expotentially as speed increases. ie: V². Thus both by design intention and the limitation imposed by aerodynamic laws upon its optimum operating envelope is to remain in the low speed flight regime to be efficient. Because of that due its its size, aerofoil and consequential parasite or form and induced drag inter-relationship, it requires a lowish pitch prop for propellor and flight envelope efficiency. Engine, airframe and propellor acceleration are inter-related. Thus small diameter or high pitch props, the combination of the two being the worst, are inefficient in the LT-40 scenario proposed. Too small a diameter doesn't produce enough accelerative thrust because of slippage losses failing to accelerate that small mass of fair to sufficiently high a speed vs airframe weight & drag. Similarly the consequence of using too large a diameter where the prop again becomes innefficient through its inability to accelerate the now larger mass of air against the drag of the airframe without loss again resulting in slippage and prop inefficiency. Increasing pitch in conjunction with the lower RPM imposition of the increased blade diameter similarly exacerbates this effect as it did with the too small a diameter. Exacerbating it further with a highly timed 2 stroke like the TT46, you're loading it below its optimum torque and power curves resulting in totally porked acceleration and power delivery. Now putting that into perspective here, a 12x6 is a big ask of a .46 at any time, and for this combo, if you'll pardon me saying so, unwise. Or translating that into non-techno speak, "pulling power" is exactly what it won't deliver. A 12x4 narrow blade might just work, but the optimum efficiency for the combo is undoubtedly sized between an 11x5 and 11.5 x 5. Propellor brand doesn't matter, though APC and Bolly Sportsman props are both efficient though broader blade designs. Now the TT46 is a good engine, but with only about the equivalent power of the long since superceded OS 46SF. An OS 46FX, AX or Enya CX45 it ain't, and even they'd be bogged down by the sizing suggestions you've recommended. With a 12x6 will it fly? Yes. Will it fly well? No. |
RE: lt-40 prop
Sigrun I respectfully disagree. Most 46 size 2 strokes recomend an 11-6 as the starting prop or as one of the alternative props. An old rule of thumb on engine loading is go up 1 in diameter and down 1 in pitch, or vise-versa. When propping a trainer one is looking for pulling power,not speed. The larger the prop diameter the more power, more disc area. You want to accelerate out of a potential bad situation. You cannot do that with a small diameter prop. It would take too long to build up enough speed and thrust to get out of trouble.
The TT 46 pro is a strong engine it will be able to pull the bigger prop. BTW the 12.5x3.75 is a funfly prop. They are all about pulling power. They need thrust to hover and do the things they do. So this would be a great trainer prop. And that prop was designed specificly for the 40-46 size 2 strokes. I will stand by my original statement. If someone else would like to chime in. I may have forgotten or missed something. Respectfully- Mark Shuman BTW I suggested a 12-5 not a 12-6. I agree a tt 46 Pro would struggle a bit with a 12-6 |
RE: lt-40 prop
The TT 46 pro is a strong engine it will be able to pull the bigger prop. BTW the 12.5x3.75 is a funfly prop. They are all about pulling power. They need thrust to hover and do the things they do. So this would be a great trainer prop. And that prop was designed specificly for the 40-46 size 2 strokes. |
RE: lt-40 prop
ORIGINAL: sigrun ORIGINAL: phread59 11-6 apc is a good place to start. 12-5 and 12.5-3.75 is also a good choice. Will give you lots of pulling power and not a lot of speed. Just what your trainer needs. Good luck. Mark Shuman Airframe drag of the LT-40, always relatively high, worsens expotentially as speed increases. ie: V². Thus both by design intention and the limitation imposed by aerodynamic laws upon its optimum operating envelope is to remain in the low speed flight regime to be efficient. Because of that due its its size, aerofoil and consequential parasite or form and induced drag inter-relationship, it requires a lowish pitch prop for propellor and flight envelope efficiency. Engine, airframe and propellor acceleration are inter-related. Thus small diameter or high pitch props, the combination of the two being the worst, are inefficient in the LT-40 scenario proposed. Too small a diameter doesn't produce enough accelerative thrust because of slippage losses failing to accelerate that small mass of fair to sufficiently high a speed vs airframe weight & drag. Similarly the consequence of using too large a diameter where the prop again becomes innefficient through its inability to accelerate the now larger mass of air against the drag of the airframe without loss again resulting in slippage and prop inefficiency. Increasing pitch in conjunction with the lower RPM imposition of the increased blade diameter similarly exacerbates this effect as it did with the too small a diameter. Exacerbating it further with a highly timed 2 stroke like the TT46, you're loading it below its optimum torque and power curves resulting in totally porked acceleration and power delivery. Now putting that into perspective here, a 12x6 is a big ask of a .46 at any time, and for this combo, if you'll pardon me saying so, unwise. Or translating that into non-techno speak, "pulling power" is exactly what it won't deliver. A 12x4 narrow blade might just work, but the optimum efficiency for the combo is undoubtedly sized between an 11x5 and 11.5 x 5. Propellor brand doesn't matter, though APC and Bolly Sportsman props are both efficient though broader blade designs. Now the TT46 is a good engine, but with only about the equivalent power of the long since superceded OS 46SF. An OS 46FX, AX or Enya CX45 it ain't, and even they'd be bogged down by the sizing suggestions you've recommended. With a 12x6 will it fly? Yes. Will it fly well? No. WHAT?[sm=bananahead.gif] |
RE: lt-40 prop
Thanks for all the info. I'll try an 11x5. I am currently flying a 10X6
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RE: lt-40 prop
I tried a lot of different props after I passed my wings on an LT40. I found a noticeable improvment when I went to a MAS 11-5 prop. The TT is a good engine and you will get a lot more use out of it with the 11-5! :))
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RE: lt-40 prop
You know what? on paper and in theory, it may fly like crap, but I've got an Evolution .46 engine on my LT40 taildragger, and it flys VERY WELL with a Top Flite 11x7 Power Prop. If you take about 1/8" to 1/4" of incidence out of the wing, the LT40 becomes a whole different plane.
ORIGINAL: sigrun ORIGINAL: phread59 11-6 apc is a good place to start. 12-5 and 12.5-3.75 is also a good choice. Will give you lots of pulling power and not a lot of speed. Just what your trainer needs. Good luck. Mark Shuman Airframe drag of the LT-40, always relatively high, worsens expotentially as speed increases. ie: V². Thus both by design intention and the limitation imposed by aerodynamic laws upon its optimum operating envelope is to remain in the low speed flight regime to be efficient. Because of that due its its size, aerofoil and consequential parasite or form and induced drag inter-relationship, it requires a lowish pitch prop for propellor and flight envelope efficiency. Engine, airframe and propellor acceleration are inter-related. Thus small diameter or high pitch props, the combination of the two being the worst, are inefficient in the LT-40 scenario proposed. Too small a diameter doesn't produce enough accelerative thrust because of slippage losses failing to accelerate that small mass of fair to sufficiently high a speed vs airframe weight & drag. Similarly the consequence of using too large a diameter where the prop again becomes innefficient through its inability to accelerate the now larger mass of air against the drag of the airframe without loss again resulting in slippage and prop inefficiency. Increasing pitch in conjunction with the lower RPM imposition of the increased blade diameter similarly exacerbates this effect as it did with the too small a diameter. Exacerbating it further with a highly timed 2 stroke like the TT46, you're loading it below its optimum torque and power curves resulting in totally porked acceleration and power delivery. Now putting that into perspective here, a 12x6 is a big ask of a .46 at any time, and for this combo, if you'll pardon me saying so, unwise. Or translating that into non-techno speak, "pulling power" is exactly what it won't deliver. A 12x4 narrow blade might just work, but the optimum efficiency for the combo is undoubtedly sized between an 11x5 and 11.5 x 5. Propellor brand doesn't matter, though APC and Bolly Sportsman props are both efficient though broader blade designs. Now the TT46 is a good engine, but with only about the equivalent power of the long since superceded OS 46SF. An OS 46FX, AX or Enya CX45 it ain't, and even they'd be bogged down by the sizing suggestions you've recommended. With a 12x6 will it fly? Yes. Will it fly well? No. |
RE: lt-40 prop
11x7 APC
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RE: lt-40 prop
body txt deleted by sigrun
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RE: lt-40 prop
Master, nah just making a point. Pulling power is an advantage when first learning. That particular prop will give you lots of pulling power quickley. That is what it is designed to do. Just thought I would suggest it. I don't expect a noob to be prophanging a trainer.
Mark Shuman |
RE: lt-40 prop
Gee, what a coincidence! I happen to be flying an LT-40 w/TT 46. I started out with an APC 11x5 and it worked GREAT but barely nick the tips on a not-so-smooth landing and they break. I'm now running the MA 11x5. The MA is a little less efficient (some say a LOT less efficient) prop than the APC but holds up to accidental bumps much better than the APC.
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RE: lt-40 prop
ORIGINAL: sigrun ORIGINAL: phread59 11-6 apc is a good place to start. 12-5 and 12.5-3.75 is also a good choice. Will give you lots of pulling power and not a lot of speed. Just what your trainer needs. Good luck. Mark Shuman Airframe drag of the LT-40, always relatively high, worsens expotentially as speed increases. ie: V². Thus both by design intention and the limitation imposed by aerodynamic laws upon its optimum operating envelope is to remain in the low speed flight regime to be efficient. Because of that due its its size, aerofoil and consequential parasite or form and induced drag inter-relationship, it requires a lowish pitch prop for propellor and flight envelope efficiency. Engine, airframe and propellor acceleration are inter-related. Thus small diameter or high pitch props, the combination of the two being the worst, are inefficient in the LT-40 scenario proposed. Too small a diameter doesn't produce enough accelerative thrust because of slippage losses failing to accelerate that small mass of fair to sufficiently high a speed vs airframe weight & drag. Similarly the consequence of using too large a diameter where the prop again becomes innefficient through its inability to accelerate the now larger mass of air against the drag of the airframe without loss again resulting in slippage and prop inefficiency. Increasing pitch in conjunction with the lower RPM imposition of the increased blade diameter similarly exacerbates this effect as it did with the too small a diameter. Exacerbating it further with a highly timed 2 stroke like the TT46, you're loading it below its optimum torque and power curves resulting in totally porked acceleration and power delivery. Now putting that into perspective here, a 12x6 is a big ask of a .46 at any time, and for this combo, if you'll pardon me saying so, unwise. Or translating that into non-techno speak, "pulling power" is exactly what it won't deliver. A 12x4 narrow blade might just work, but the optimum efficiency for the combo is undoubtedly sized between an 11x5 and 11.5 x 5. Propellor brand doesn't matter, though APC and Bolly Sportsman props are both efficient though broader blade designs. Now the TT46 is a good engine, but with only about the equivalent power of the long since superceded OS 46SF. An OS 46FX, AX or Enya CX45 it ain't, and even they'd be bogged down by the sizing suggestions you've recommended. With a 12x6 will it fly? Yes. Will it fly well? No. |
RE: lt-40 prop
ORIGINAL: FlyerBry If you have had experience with a TT .46 Pro of your own then yours must have been a lemon or broken in wrong! I have 2 and they have both been complete gems. These are every bit as powerful as an OS .46 FX. Even Thunder Tiger themselves haven't the audacity to make such an blatantly errant & outrageous statement in their usual exaggerated advertising blurb, inarguably a sin from which no manufacturer is sacrosanct. And I quote them; (peak) "power output 1.43 at 16,000". Take a guess what it is for the FX & AX? For the SF? :D Like I said, inclusive of an identical peak power performance specification, it's a fine carbon copy of the SF. Not altogether a bad thing some might say, but as powerful as the FX be it on paper or in the air it's not. For you to opine otherwise against what amounts to the the undeniable empirical evidence and the math says all we need to know. Thanks for making a noise. :D |
RE: lt-40 prop
The APC 12.25-3.75 is actually designed for control line. Check out [link=http://apcprop.com]www.apcprop.com[/link]
Cheers, |
RE: lt-40 prop
For all those beginners out there don't be misled by sigrun's heavy use of the dictionary as an indication of his knowledge of engines. It is common knowledge that comparing engines strictly by the numbers doesn't tell the full story on how they perform in comparison to one another. I invite you to do a search here on RCU and look at the posts for both engines. You will actually find more people who have had problems with the FX than the TT. Is the TT a copy of the SF? Well I would say it is indeed related since Thunder Tigers main engineer came from none other than OS! The truth in the matter is that OS engines are machined to tighter tolerances than TT and many other brands. This basically results in a slightly faster break-in and a little nicer final finish on the parts. Once broken in these two engines are all but interchangeable. Either of these two engines will pull an LT-40 around quite nicely.
This past summer I helped a flying buddy of mine get his nephew set up flying on a used LT-40 that came with a TT .40 Pro (not the .46) and he couldn't believe the power the engine had. Would you like to take a guess at what engine he had on his personal plane at the time? Thats right, a .46 FX. He also has an evolution (which gave him fits for a long time - even after a couple trips for warranty repair) that he says pulls harder than his FX. sigrun, maybe it is your misplaced pride that prompted you to jump on the TT. Your argument is an overgeneralization of the three OS engines you have mentioned. The general consensus at the club I fly at is the AX is a superior engine to the FX in terms of power. When this engine first came out people on these groups were comparing the AX to the FX and looking at the numbers. Seeing that they aren't much different one early consensus was that the AX was an attempt to cut costs by OS and not an improvement in performance. Now that some of these engines have gotten into the air and people have gotten some experience with them the AX is turning out to be ahead of the FX (and yes the TT too) when it comes to power. There again, the numbers don't tell the full story. ORIGINAL: sigrun ORIGINAL: FlyerBry If you have had experience with a TT .46 Pro of your own then yours must have been a lemon or broken in wrong! I have 2 and they have both been complete gems. These are every bit as powerful as an OS .46 FX. Even Thunder Tiger themselves haven't the audacity to make such an blatantly errant & outrageous statement in their usual exaggerated advertising blurb, inarguably a sin from which no manufacturer is sacrosanct. And I quote them; (peak) "power output 1.43 at 16,000". Take a guess what it is for the FX & AX? For the SF? :D Like I said, inclusive of an identical peak power performance specification, it's a fine carbon copy of the SF. Not altogether a bad thing some might say, but as powerful as the FX be it on paper or in the air it's not. For you to opine otherwise against what amounts to the the undeniable empirical evidence and the math says all we need to know. Thanks for making a noise. :D |
RE: lt-40 prop
Maybe I helped my kid build his incorrectly. We are satisfied with a 10x6.
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RE: lt-40 prop
FlyerBry I don't know whether your launching upon such a pointlessly futile and 'crushingly' personal vendetta is down to your sense of injured pride due my rebuttal or simply an inability on your part to comprehend, be it due a lack of the the basic ability to deduce or reason called logic? But again you post only superfluous noise extraneous to either the subject or objective of the thread, the facts, or what was actually written by me. And your ad hominem slur that an ability to communicate either necessitates constant reference to the dictionary or is motivated by a desire to impress is most indicative of the weakness in your own 'argument', but perhaps more so of a pompous and insecure ego of your own?
Reading your post I am at odds to find what your argument actually is, as other than constantly and unnecessarily reaffirming and proving your personal owner pride in TT, (ie: unnecessary as it's accepted prima facie per se) you keep changing your point of debate. Let's look at a few examples. ORIGINAL: FlyerBry is common knowledge that comparing engines strictly by the numbers doesn't tell the full story on how they perform in comparison to one another. I invite you to do a search here on RCU and look at the posts for both engines. You will actually find more people who have had problems with the FX than the TT. A. The FX is more popular? = True. B. The FX sold in far larger numbers = true. C. The FX at one stage had a peeling liner problem = true. D. The FX is frequently recommended as a first engine to beginners who don't know how to tune? = true. E. All of the above? I'll tell you what it's not indicative of. Power of the FX vs power of the Pro. :D Is the TT a copy of the SF? Well I would say it is So what's your beef? Are you hurt through somehow identifying with TT or feeling some sort of lesser being because of your predeliction for TT's 46Pro, which is acknowledged ispso facto by asssociation with the SF design a fine engine? That goes hand in hand with the an undenaible public domain acknowledgement of the power variance. I am almost as perplexed as I am bemused? How does attacking the messenger of that fact or either of OS's' contemporary engines help? And you go on to say; Either of these two engines will pull an LT-40 around quite nicely. This past summer I helped a flying buddy of mine get his nephew set up flying on a used LT-40 that came with a TT .40 Pro (not the .46) and he couldn't believe the power the engine had. maybe it is your misplaced pride that prompted you to jump on the TT. As it is I'm still unaware I had "jump(ed) on the TT". If you could kindly point out where I've done so other than in your own imagination? Quite to the contrary, my comments about both OS's SF and TT's Pro were complimentary. Predominently indicative of nothing other than an endorsement of their fine design accompanied by objective statement reference their relative power to one another and vs the FX/AX. Your argument is an overgeneralization of the three OS engines you have mentioned. The general consensus at the club I fly at is the AX is a superior engine to the FX in terms of power. If you want to use illustration by example, the 50SX is a much more powerful engine, but the AX is essentially still very similar internally in terms internal design, torque, power & peak curves to the FX. Be it on paper or in action it offers nowhere near the characteristic peak output variance that existed and still exists between it or the FX and the SF, TT Pro, nor their sister and acknowledged powerhouse the 50SX. In the final analysis two completely relevant facts remain. The TT.46Pro is definitively less powerful than the O.S. Max .46FX. (proven) The optimum most efficient prop for a TT .46Pro powered LT-40 combo in the training role flight envelope will prove to be either an 11x5 or 11.5x5. (supported by empirical trial and understood easily enough by anyone sufficiently erudite to understand applicable propellor theory, aerodynamics & interpret engine torque and power performance curves. There it is. Should you wish to continue denying the former or accepting of the latter is by now fine by me. You can only lead a horse to water. :D |
RE: lt-40 prop
ORIGINAL: bingo field Maybe I helped my kid build his incorrectly. We are satisfied with a 10x6. If you don't think so after trial, take it off. You have much to gain and nothing to lose for the outlay of an additional $2.49. [8D] |
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