I have three props now and I have not flown my plane yet. I just finished building it. I have a 11x6, 10x6, and 11.5x4. Which of these three would be good to start out on or should I buy another one?
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Flyn' High, Real High

I have a Hangar 9 Arrow (which is a pretty similar airframe to the Avistar) with a Magnum .46. I've used a 10x6 2-blade and the plane flies well. I've also used an 11x4 2-blade and it flew OK, at least until I put it in the ground (but that wasn't the prop's fault). My guess is you can use a range of 10x5 to 10x7 and/or 11x4 to 11x6 and be OK.

I've also used one of the Evolution 3-blade props. While it would get the Arrow off the ground, in the air the plane didn't feel as "crisp" as with the 2-blade props. On the other hand, it seemed the plane would land slower due to the increased air resistance of the 3-blade. At some point I'm thinking of trying a MA 3-blade just to see what happens.

I'm flying an Avistar / TT .46 / APC 11x5 with no problems.
I've also used a TopFlite 10x6 with reasonable performance, but I prefer the 11x5.

Why do you prefer the 11X5 over 10X6?
Also..did you have to put the battery in back to fix the CG of the plane or leave it where the manual said because of the weight of the TT.46. I have not gotton that far in setting up the plane to be flown, just finished building it.

Hey Stone,

For a trainer you want as much thrust as you can get and you want it right now. A big diameter, low pitch prop is what you're looking for

I have a H9 Arrow with an OS 46AX. It is very similar to your setup. I have used MAS 10x6, 11x6, 11x4 and APC 12.25 x 3.75. The APC has the best thrust and will climb forever, it isn't quite as fast as the 6 pitch props though. The 11x6 takes a while to spin up. The 11x4 MAS is a little small and tends to over-rev. I would try the 11.5 x 4 or buy an APC 12.25x3.75.


Chris

I want to know a good prop to start with..Everybody is telling me two or three..anybody know just ONE all around good prop?

ChrisAttebery has it dead right. Keep the 10" props in your "emergency spares" box. They just don't give everything that there is to be had from a BB .46 like a TT Pro -- especially with a "draggy" plane like a trainer.

I've flown many Avistars with OS FXs & TT Pros -- The 11 & 12" props are where you want to be. An 11-5 is good -- unlimited vertical. An 11-6 will give you a bit more speed (not that you need it) without sacrificing vertical, but will raise the landing speed a little. An 11-4 works OK if you stay away from full throttle in level flight, but it will pull an Avistar straight up 'till it's gone, and it lowers the landing speed. A 12-4 is exactly right in every way, except ground clearance -- & you can get that if you convert to a tail dragger.

While APC props really do give better performance than MAS, they break much more easily. The TT will have so much go in the Avistar that you won't need the little bit extra available from APC.

Regarding balance & the battery -- move it aft as far as necessary -- don't add useless weight like lead to balance the plane.

So an 11X5 or 11X6? or is there a BIG difference?

Stone,

The 11.5 x4 you have will work fine, just don't fly it wide open in level flight. You shouldn't be flying wide open while you're training anyway, except for takeoff and to get out of trouble. Once you get used to the plane you could try a 11x5 or 11x6 to get some more speed, at the cost of a little thrust and response.



Chris

Use which ever one you have -- there isn't a troublesome difference, like there would be if you used an 11-7 (too much prop) or a 10-6 (not enough prop).

I use 11-6s for general flying with my two Superstar hot rods (on wheels, or floats) but an 11-5 will work as well -- I just like the extra bit of speed.

Haven't we been through this issue already?
I understand that you want to build your plane as perfect as it can be, but with a TT 46-pro you're a bit overpowered anyway and will unlikely go full trottle to gain maximum speed.
I'd say that the 11x5 is a good choice since it provides a tad more thrust which is more useful than pure top-speed in a trainer.

As a total beginner you'll never notice the diffrence from a 11x5 or 11x6, you'll be busy flying, not performance tuning.

...Concentrate on getting that plane ready and get flying.
Eventually you'll get your own opinion on the prop-sizes.

As far as balance goes, I can't give you an accurate answer because I'm the 3rd owner (plane is at least 10 yrs old) and when I got it, it had a piped K&B .40 on it that was very unreliable. I just put the TT (which is actually an early Magnum Pro .46 SE that became the TT Pro after the conflict back in the 90's) on it and balanced it at the main spar. I've never flown or balanced it with any other setup.

As was mentioned, a beginner doesn't really notice monumental differences in a prop-size or two (at least I didn't, anyway). I started with an 11x4, broke it, and went with the 11x5 APC at my instructor's suggestion. It does seem a tad slower on landing and has plenty of power when needed. I still keep 10x6, 11x4, and 11x5 in the flight box, though.

Stonedeaf,

An 11X5 will do just fine. You already have an 11.5X4 which will be very simular to the 11X5. It is somewhat hard to suggest just one prop as the airframe, engine, engine tuning, the way you fly will all play a factor.

As far as CG goes, get everything setup on the plane except for the battery and leave it unplugged from the receiver for now and put the battery in the location but do not tie it down in any way as shown by the manual, put the wing on and check balance. If it shows tail heavy then move the battery towards the front of the plane to where ever it will fit and recheck balance. If it shows allot of nose heavy then move the battery back until you get the plane level of only slightly nose heavy.

On the other thread you created it was described as to how to use the battery to balance the plane and also how to check the CG in the first place.

The instructions for that plane are pretty good and if followed you will be amazed at how well it will all come together, all you need to do is settle down and think things through a little more. I do understand the desire to "get it right the first time" and to completely understand your airplane (I always research a new plane I'm considering before actually buying it) but trainers are very forgiving planes and if you remember that fact, things will go much smoother. Once you get to join a club then they will most likely checkout your plane before it ever leaves the ground.

Now walking into a new club and having a plane that is properly balanced, well constructed and the pilot having everything to fuel, start and fly the plane really shows that you are on the ball and are commited to doing it properly will go a long way and I am sure that is what you are trying to do.

I am not trying to bash on you or make you feel bad so please do not take it that way.

Thanks for all your help. I am having a guy from a local club help me tonight to finish working on it and get everything right on it so it will be ready for Sunday if there are any instructors available that day.

Just a point of interest krossk -- the TT Pro is not an early Magnum Pro .46 SE. It was a new-from-scratch design, with its inspirational antecedent being the OS FX .46, & it had the former OS engineer who designed the FX as its designer. It incorporated changes that OS was not prepared to retrofit into the FX. The designer's name escapes me at the moment -- oldtimers disease.

From personal experience: with 2 stroke engines, stick with 2 blade props. 3 bladed props lose a lot of efficiency at the high rpms of 2 cycle engines. For 46 size engines, stick with 11" props. I tried a 10-7 prop with a 46FX engine and it worked pretty good. Then I tried an 11-6 prop and it worked much better. Then I went down to a 11-5 prop and it was better for all around use. It gave quicker accelleration when I hit the throttle, better pull in the turns, faster takeoffs, and better pull when gaining altitude. It might be a bit slower than the 11-6 in a flat out run but in most situations it was actually faster due to the better pull. For instance I noticed that the plane didn't lose speed in a hard turn like it did before with the 11-6 prop. Doe this help??

Hey StoneDeaf.. I had a Avistar/LA-46 And the one prop I used was the APC 11/6 It gave me good all around performance and the needed puff-of-saving air when needed in those " come on pull-up baby moments"..

When I started flying a couple of years ago. I had a 46FX on a Super Star. I used a MAS 11x7 which worked great. A 11x5 or 11x6 would work fine also, but my favorite was the 11x7. I used a MAS because it is the best prop to learn to land with. APC props don't take ground strikes too well. Plus the MAS provides better breaking on landing approaches. I did a maiden for a pilot that is using a 50SX on a super star trainer. He is using a 11x7 also with great happiness.

A guy that is helping me build my plane now said I should put a 10x6 on it now to start out with.

Dead wrong -- the manufacturer only recommends the 10-6 for break-in. The disc area is too small for a slow draggy airframe & the pitch is too low for the disc area -- insufficient power load. This means poorer acceleration, poorer climb, excessive loss of speed in turns, higher landing speed & too many engine revs. But it's yours, so go ahead.

A 10-6 is suited to a smaller, weaker engine, like an OS .40 LA, or a good 32.

I flew my Avistar with an OS 50 SX and a 10x8 prop. I chose a 10" prop instead of an 11" prop to give me some more ground clearance on my hard landings (I tended to bump my prop when I was first learning)! With this combo, I had plenty of thrust and speed. I'm sure the TT .46 isn't quite as powerful as the OS 50 SX, so you may want to drop to a 10X7...

The TT will pull a 10-8 just fine, but it is a long way from an ideal prop for a trainer.

MA 12x4

The 10x8 will put roughly the same engine load as a 11x6, BUT the 10x8 is going to fly the plane a lot faster with less thrust. The 11x6 would have more thrust with a little less speed on top end. A 10x9 would have the same load as a 11x7. A 12x5 or 12x4 would give you even more thrust with a little less top end. Trainers are not designed to go fast anyway, so I always recommend to my students to get more thrust than speed right now. More thrust can get you out of trouble if you need it. A 10" prop is too small for a 46 unless you are looking for speed, which I would think a person on a trainer is not looking for when learning and/or developing his or her skills. More thrust will lift the plane off the ground faster and the bigger prop with lower pitch will have more braking affect on the landing approach which really helps new pilots.

It seems the bottom line is that you can put anything from a 10 x 6 to an 12 x 4 or so and be just fine..... anything will work....
you just will get slightly different results with each one