This is already a question here, but i want to know for my scenario. My plane is going to be a Kadet MKII...engine will be a TTPro.46(hopefully if i can get one)...im a beginner, but a very quick learner(can be a curse sometimes). Which will be the best prop size for me for learning takeoff, landing, basic flight, then kicking it up a notch to some faster flight and flight maneuvers, all while keeping the engine from over revving.?? All help is appreciated. Thanks--Nathaniel

You get a different opion on props.
In my opion i would use a 10x6 or 11x6.

I would personally start out on an 11X5 which will give nice pull but not allot of speed and will give good braking for landing. When you are comfortable then slowly increase the pitch while leaving the 11 inch diameter say move to a 11X6 and if you want more speed then go to a 11X7.

Remember that will larger pitch, there will be less braking for landing and also do not go to large on the pitch and it can actually start to load the engine to much and slow the plane down while overheating the engine.

just so i know, what are the numbers indicating in the size. Eg: 11x6(lengthxpitch)?

11 is the length (in Inches)

6 is the pitch - meaning that if the prop rotated one full revolution, it would (Theoretically) move forward 6 inches

As randy41 said, "you will get a different opinion on props" -- he's right. I agree with his 11-6 choice & Bubbagates 11-5 choice, but I disagree with randy41's 10-6 (not enough prop for a TT .46 pro -- unless it is for break-in) & I disagree with bubbagates 11-7 (too much prop for a TT .46 Pro -- particlarly on a slow draggy crawler like the Kadet Mk II). An 11-4 is another viable choice if you stay away from full throttle in level flight.

You might just be right. One thing we all
have agreed on thus far is the 11x6. Thats
a good thing dont you reckon.

OK Britbrat...that's it, let go outside and settle this [sm=punching.gif]

Just kidding , you are right, I did not take into account the draggy airframe. I think the 11X4 would be good but not knowing a whole lot about that engine, wouldn't that be to high of an rpm at full throttle, just asking. [sm=confused.gif]

Merry Christmas [sm=biggrin.gif]

I used an 11x7 on a Magnum 46 (Don't have a TT Pro 46, but want one. Maybe Santa will bring one) on my Avistar. IT was not a bad prop for the Magnum, but only trouble was at idle it carried too much speed for landing. I would guess that the Kadet will probably be the same.

I think you'd be happy with the 11x6 as indicated by the fine gentlemen above.

Duke

You may find that one brand of 11 x 6 will fly your airplane one way, and another brand of 11 x 6 will fly it another. When you get to the point where you are flying the airplane well enough to tell the difference, invest in several different brands of props in reasonable sizes. I suspect you will learn that not all 11 x 6's are created equal.

More good advice from Jim Thomerson. I find that APC props will sometimes turn more revs & give more thrust than a MAS prop, for example -- but not always -- so experimentation really is the word.

The 11-4 works pretty well at full throttle with the TT in the vertical (probably unlimited vertical with the Kadet), but it will indeed turn pretty fast in level flight -- not engine blowing stuff, but faster than necessary.

OK bubba, but if you're under 60, I'm going to use a "pinch hitter" [sm=punching.gif]

I think you made a great choice on first airplane. It was my first one also and I loved it, and to you guys who called it a "slow draggy flyer", thpthpthpthpthpthpthp. It is not, too! But seriously , I hope you get as much enjoyment out of yours as I did mine. It's an older, well proven design. The only thing I did differently from the instructions was to take half the dihedral out and add 1 bay to each wing (about 3 inches). Talk about a floater! . I started out with a Tower .46 turning a 11-6 three-bladed prop, and I also flew it with a 11-6 and 11-5 two bladed props. I agree the 11-5 is probably the best to learn on, allows plenty of rpm's but not a great deal of speed and good braking on approach. I assume you've already built it, but if you haven't I would recommend taking out some of the dihedral, especially if you are a "fast learner". The plane could do without ailerons with as much dihedral as it has, I found it to be very responsive but still very stable with the decreased dihedral. stretching the wing is totally unnecessary, though, I found it hard to land with any wind blowing, it wanted to keep flying.

One big recommendation, though. Stay away from 1/4 scale Cubs while flying. In a mid-air they will eat your lunch. My poor Kadet is now balsa confetti, courtesy of a G-26 and a 20 inch prop.

I'll send one of my daughters but wait. I want to print some tickets

A 11x4 is just right but a 10x6 is not enough? Come on... anything from a 10x6 to 12x4 will work just fine on the 46 (11x5 being the favorite with prop clearance and pull-)

Just stay with APC---

It was not suggested that an 11-4 is "just right". As you will note, if you re-read the post, there are suggested limitations on the 11-4. Aside from that, there is a significant difference in performance between an 11-4 and a 10-6 -- while they have similar power loads, the 11-4 produces substantially more thrust than a 10-6, & the greater disc area is particularly important with a bulky, draggy airframe like the Kadet MkII. If the airframe had been much slimmer & cleaner, the 10-6 could be a good choice -- but not for the Kadet. Additionally, TT only recommends the 10-6 as a break-in prop for the .46 Pro.

My favorite prop for the TT 46 is the APC 11.5x4.

Well...thank you all for the info. I seriously love how these threads always turn into debates, because there is no better way to average out the opinions than when there is alot of them. I am beginning to understand the prop/engine ideals. One thing though, can you have too much pitch. And if so, what is the negative to this? I know over-revving is not good, but with too much pitch, does an engine actually work too hard, or does it just haul your plane around fatser?

You very definately can have too much pitch, & it can do bad things to your engine.

As you increase pitch, the engine revs will fall (there is only so much torque available to turn the prop), but the engine works harder despite the lower revs. If the load is sufficient, the revs will fall out the bottom of the engine's usefull power band -- you will make much less power than previously & less power means less speed, climb etc. The increased load will push engine temps upward -- even to the point where the engine can seize if the load is severe enough. Additionally, the higher combustion pressures resulting from the overload, will increase radial thrust loads on the crank bearings (or bushing), increase shear loads on the crank pin and increase side thrust on the piston. None of it good. Even if you don't have a catastrophic failure from overload, you will be shortening the engine's life. It is every bit as bad as sustained high revs.

In terms of flight performance, you can easily have situations where a flatter pitch prop will give you greater level speed & much better climb than a steeply pitched prop. You read about pilots who claim that their .46 LA runs fine on a 10-8, or 11-7 prop, or even in one case I saw -- a 12-7 !!!! Too bad for the poor engine -- & too bad for the pilot who is only getting a fraction of the performance available from that engine.

Gotcha...thanks for the explain.