jaka

Hi!
11x6 is just fine! 12x4 is even better on a High winged trainer. Just use throttle to control decent!

The first thing to do when flying a plane is to check the C of G ...up high. The goal is always, regardless of plane typeto have the C of G placed so that the plane will stall when the speed is reduced to a near stand still and at the same time have full up elevator.
If the plane just mousses forward at that point the C of G is located too far forward. -Simple as that!

-pkh-

My Feedback: (2)

In general I find MAS props are a little slower than APC props of the same size. So in addition to changing size/pitch, I'd suggest going with an MAS over APC.

spidr_01

thank you everyone, this is a great help.

Campy

My Feedback: (1)

If you have an APC (grey) on the plane, change it to a MAS (Master Airscrew) black with the squared off tips. That MAS is only about 80% as efficient as the APC.

My Sig Rascal 40 with an OS 46FX and APC 11x6 refused to land !! It would float 6" off the ground the full length of the field (600'), unless I killed the engine and did a dead stick.

I changed the prop to a MAS 11x5 and now the plane lands with no problem.

carrellh

The props listed in the tech notes and manuals are just guidelines. The manufacturers will never be able to test every possible combination. You can use any prop that runs well without overheating and flies the plane the way "you" like.

You could switch to a 10x5, three blade such as http://masterairscrew.com/new10x53-b...propeller.aspx
The engine will likely turn several hundred rpm more than with the 11x6 but top speed "should" go down by about 9 mph.

If landing speed is the issue, I do not believe the prop is the problem. At 2500 rpm, a 6 pitch prop would only want to go 14 mph under laboratory conditions so I think the others are right that the plane is coming in 'nose down' and gaining speed because of that.

jeffie8696

Ihave to ask, is the teacher trying to slow the plane down on landing or the top speed?
Ihave been flying my Tower40 trainer with a Magnum 52 four stroke and recently with an Irvine 53!
Ifind the ground clearance to be an issue with 12" props and not that much fun with 11" . Iprefer 10" props to keep it from mowing the lawn or striking the ground on a rough landing. Nothin wrong with 3 bladed props and lately I have been using some 10" wood Zinger wide blade props that can really move the air. A 10X8 Wide is currently on my Irvine 53 and it is working fine.

Does your Tower40 fly tail heavy even though the balance is correct?

thailazer

As I mentioned in my earlier post, my CG is 8 cm back from the leading edge of the wing with no fuel. It trims hands off at half to full throttle, and below that, a couple clicks of up and it again is trimmed for hands off flight on either the original or my bigger wing. Great flying airplane and it lands very slow with excellent flare capability even at low speed.

spidr_01

no, it actually fly's nose heavy when fueled. He is wanting to slow it down on all aspects. like in the patern and on aproach. We curently fly on half throttle. today I flew a 11X5 prop and on a bad landing I brok it. the only other prop i had was a 11X6, and I really see the diffrence. the 11X5 made a better beginner performance, but the 11X6 gave me unlimited climb.

spidr_01

almost forgot, I did see the video. Ilikethe bigger wing. looks like you get great performance.

jeffie8696

If you are trying to slow it down on landing just getting a good low idle speed may help. Ishoot for 2000 to 2500 rpm consistently. Ihavent seen any trouble at these low rpms with any prop Ihave ever used. As far as top end you could always use a 3 blade 10" glass filled nylon like a Master Airscrew or Graupner. You can probobly get away with a 5 pitch. Iprefer the MA props for their ruggedness.

thailazer

Like several posters have offered, moving the CG back would likely have the biggest effect on your approach speed. Idle and props do have an affect, but the Tower Trainer with a proper CG can almost land itself at many low power settings.

When a plane is nose heavy, the horizontal stab and elevator are not effective in getting the nose up to slow the approach speed. A heavy nose will pull the nose down and the plane speeds up even with back pressure on the stick. Get the CG in the right place and the elevator can be effective in placing the aircraft in any attitude for speed control.

CGRetired

My Feedback: (1)

I played with the CG on my Skylark 70 just as you suggested. I ended up with a plane that will do the circuit just as pretty as you can imagine. Then, I follow the downwind, base, final type of approach, following the "rules", and it glides in just about perfect each and every time.

One day, I was flying with my head up my butt.. I had the wind backwards, and was actually landing with the wind rather than with it on the nose. The landings were long.. every darned one of them, until someone said that my downwind landings were nice, but long. I looked at the guy like he had three heads, then suddenly realized what I was doing. But, even the long landing approaches were nice because everything was right (except for having the nose into the wind, of course).

I pretended that I had intended to land that way, we all had a good laugh about it, then I proceeded to land correctly. Geee.... the thing landed right in front of me for some reason. BUT, again, the flair at the very end of the glide slope was pretty as a picture... and it was because the CG was in the sweet spot.

CGr.

jeffie8696

Ilearned on the PT-40 trainer and now have a Tower40 (due to an electrical failure) and find the Tower40 doesnt fly as well.
Perhaps it is the uber low wing loading? Ijust dont know, but it isnt half as nice to fly as the PT-40.
Flies like it is tail heavy even though it balances out. Ihave tried changing the CG, engine thrust angle, tirms, aileron angle,just dont have it yet.
It has been suggested the wing incidence needs changed.
Anybody else have this trouble?

oldtyme

I agree..........I'm flying a GP Escapade with an OS46FX and I'm running a Master Airscrew 10x6 and it's quite docile......a good fit for that engine.

oldtyme

OOPS, I didn't notice that you said a "3-blade 10x5" but the 2-blade 10x6 is still a good choice.

shaggy48

I too have the tower trainer 40 it does fly like its too heavy.

charlie111

You could de-tune your motor by running it at full throttle and open the mixture screw in very small incruments turning it counter clockwise will bring your r.p.m.s down.Not really recomended it will affect the idle also even a 1/4 turn will make a big difference it might also be a little sluggish reving up.Just a thought?

j.duncker

My Feedback: (2)

Here is another vote for the APC 12.25 x 3.75