Daryl Martel

My Feedback: (3)

I was flying my Wasp today and chipped an APC prop tip on landing. I don't have a lot of clearance (note to self - buy those darned Krazy Legs soon!) so this isn't unusual. This necessitated a prop change so instead of the 12 X 6 I run on my Irvine .53 I thought I'd try a 13 X 6. What a difference - without touching the needles (didn't seem to need it) I noticed an immediate increase in thrust. All of a sudden I found I could do harriers consistently and was motoring around dragging my tail all over the field. I do notice acceleration isn't quite as good but it still has outstanding vertical. The revs definitely dropped (quieter!) and I noticed the motor was hotter as a result of the extra load, but this engine has the guts to handle it! Now I can see why the light 4 strokes are the hot tip on these fun fly planes. That ability to turn the bigger diameter props gives you greater thrust and better high angle of attack capability (read easier to fly). Wow - what a great afternoon flying!

whstlngdeath

My Feedback: (15)

I always experiment with different props on each and every engine I install. I sometimes go way outside the "recommended"
props. I like the larger diameter props but I usually go a little shallow on the pitch. That gives great pull but sacrifices top speed. I do most of my flying at half throttle, and I like the nice slow landing speeds. By going shallow on the pitch, though, it makes the plane a bit noisier and brings on different harmonics and vibration. It's fun to find out these things and work with them. Keep having fun,

Jesse

Gordo-ProBro

Daryl, try the APC 13x4w. I've found this to be a great prop for slow flight, hovers, etc. My OS50 digs it. It may help to keep the temp down.

Daryl Martel

My Feedback: (3)

Gordo-plast - thanks for the tip. I think I will try a 13 X 4W if I can get my hands on one. I think I'd appreciate less pitch/speed.

Billy Hell

My Feedback: (2)

Very interesting. I see a lot of guys go down to say an 11x4 to get good throttle response but I don't hear about going up to 13 too often. If this is the case for you guys then I'm in. Nothing better than a big prop to make everything easier to do.

NM2K

My Feedback: (14)

If you had your engine tuned properly to spin the 12x6, it is difficult to understand how the high speed needle did not need to be opened up a bit.

I sure would hate for you to loose some of the life of that fine Irvine .53 engine.

Don't be afraid to adjust that rascal any time you are near it. After a while, tweaking will become second nature. Maybe it has already and I'm worrying for nought. <G>

Gordo-ProBro

I get You Billy Hell, not much talk of going that big. I don't spread it around much 'cause the "smart guys" tell me how it's all wrong.

Lots of guys figure a .40 gets a 10x6, and a strong .46 or .50 might be able to handle a 11x7, but 12, 12.25 or 13 inch props? No way. If I remember right, they quote the manufacturer's RPM and Torque numbers, and kindly explain that I'm not "in the power band" and that I'm not "getting all I could".

Then I just go and pull my plane off the deck in 3 feet, go straight up 'til it's a blip, flat spin all the way down and then pull into a hover a 1/2 throttle (well sometimes it actually works). They usually shut up.

I've got a reputation as the guy "with all the props", my bottom drawer of my flight box has probably 30 props in it. I love to experiment. I figure if it flies well, temps don't go too high, and the plane has ground clearance (that CAN be modified at the field!) I go for it.

Daryl Martel

My Feedback: (3)

Hi Ed - I dunno, just switched props, it ran OK so I flew it. I don't set the high end for absolute max RPM anyway, so I probably had a little "room" to play with. I do think that after the flight the engine felt a bit hotter than when running the 12 X 6, but it certainly performed great in the air with the 13 X 6, not a hint of being too lean. Sure impressed me! I find the Irvine a nice engine to set up, easily on par with O.S. I've got a nice tach, but didn't feel the urge to pull it out and check the RPM. I did notice (understandably) an audible RPM drop with the bigger prop.

777M8

I think 30 props might be an understatement but bigger and flatter in this case is better

funflyer06

I was running an 11x5 on my Somethin' Extra. It would just barely climb, very very slowly or sometimes not at all. Then today I switched to a APC 12.25 x 3.75. I can go from a hover to a climb. Its still slow but I love this prop. It works fine on my TT. 46. I've been getting 1 1/2 - 2 torque rolls before I would fall out. I have to cut the power when I land so as not break the prop because I only have 2.

Gordo-ProBro

Funflyer: I assume the "cut the engine" comment means that you're using the stock gear. I'm a big SE fan (Did you know they would cartwheel down the runway?) and I consider the dubro "60 sized" fiberglass gear to be standard issue. Plenty of room for 12" and 13" props.

Bill: cute avatar, did you do that just to get me? I'm gonna build a coro-knife just to bug you!!! See you Sunday eve? Knife is ready for maiden! Even changed the color scheme.

Later

777M8

Ok Gordo you might as well build that plastic Knife ( hey that sounds kind of funny) you don't like to build balsa ones
See you at the feild. Bill

funflyer06

Gordon, yes i am using the stock landing gear. When I wrote the post I had smaller wheels on it. Now I switched to some bigger foam ones so as not to add much weight. Now I can land it without fear of breaking the prop.

What do you mean by cartwheel down the runway? Do you do it on purpose and then is it still flyable?

Gordo-ProBro

No, definately not on purpose! Had somethin' weird on takeoff, caught a wingtip, rolled wintip to engine to wing tip to tail to wingtip (you get the idea) about 2 times. all it did was rip the wingtub out of the fuse and bent the AL tube a bit. Cool.

Gordo