Matching Engine, Prop and Plane?????
08-06-2004, 03:09 PM
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Matching Engine, Prop and Plane?????
Hello -
I'm having difficulty matching up props with engines and planes.
An example: I've got a Phoenix Sukhoi with a Magnum 52. The engine runs great and the initial flight was with an 11x7 prop. The plane was almost uncontrollable! I put an 11x5 prop on the engine and the plane flew pretty well. A little more tinkering and I found that a 12x4 prop simply made the plane wonderful to fly.
I've got a Lanier Stinger 60 with a Saito 100. By trial and error I have found that that combination with a 15x6 prop is the best. The Stinger was much more forgiving early on compared to the Sukhoi.
How can I get the match right the first time without putting my plane in danger? The prop charts that come with engines seem to have a rather large range.
I've got a Giant Scale Planes Corsair with a Saito 150 for power. What prop should I use for the first flight?????
Thanks a lot for your comments and suggestions.
Brian
I'm having difficulty matching up props with engines and planes.
An example: I've got a Phoenix Sukhoi with a Magnum 52. The engine runs great and the initial flight was with an 11x7 prop. The plane was almost uncontrollable! I put an 11x5 prop on the engine and the plane flew pretty well. A little more tinkering and I found that a 12x4 prop simply made the plane wonderful to fly.
I've got a Lanier Stinger 60 with a Saito 100. By trial and error I have found that that combination with a 15x6 prop is the best. The Stinger was much more forgiving early on compared to the Sukhoi.
How can I get the match right the first time without putting my plane in danger? The prop charts that come with engines seem to have a rather large range.
I've got a Giant Scale Planes Corsair with a Saito 150 for power. What prop should I use for the first flight?????
Thanks a lot for your comments and suggestions.
Brian
08-06-2004, 07:05 PM
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RE: Matching Engine, Prop and Plane?????
Brian,
Start here, and then experiment. Different planes use different props for different applications. I have a H-9 Arrow and the three blade prop that came with it is terrible, but put on a 10X6 it's not bad, an 11X5 is the best so far.
Keep in mind that if you want a lot of vertical performance, use a very low pitch. More speed needed? Go for a higher pitch number. Start somewhere near your "ideal" set up, and change the prop one number at a time.
Go into a vertical climb, do you have enough oomph? If not, try a lower pitch. If you have to fly wide open all the time just to stay above stall, use a higher pitch.
Not much help, I know, but the short answer is: experiment, the difference will be subtle, but noticeable.
Start here, and then experiment. Different planes use different props for different applications. I have a H-9 Arrow and the three blade prop that came with it is terrible, but put on a 10X6 it's not bad, an 11X5 is the best so far.
Keep in mind that if you want a lot of vertical performance, use a very low pitch. More speed needed? Go for a higher pitch number. Start somewhere near your "ideal" set up, and change the prop one number at a time.
Go into a vertical climb, do you have enough oomph? If not, try a lower pitch. If you have to fly wide open all the time just to stay above stall, use a higher pitch.
Not much help, I know, but the short answer is: experiment, the difference will be subtle, but noticeable.
08-06-2004, 09:09 PM
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RE: Matching Engine, Prop and Plane?????
Well, with a warbird (as with an aerobatic plane), I think you'd be better off with a slightly larger diameter/smaller pitch prop. Say a 16 X 6 with the Saito 1.50.
The 6 inch pitch should give you enough speed for good fying, while the larger diameter will give better torque for shorter take off runs and improved vertical.
Larger pitch and smaller diameter will require a longer take off run, and give you less "grunt" for pulling the plane around. This was likely the initial problem with the Sukhoi. Aerobatic planes simply do not fly fast very well, and the higher pitch prop wasn't efficient. Once you lowered the pitch and increased diameter the plane found it's sweet spot. (Lower top speed but more vertical pull.)
Just my opinion of course.
Dennis-
(Edited for spelling.)
The 6 inch pitch should give you enough speed for good fying, while the larger diameter will give better torque for shorter take off runs and improved vertical.
Larger pitch and smaller diameter will require a longer take off run, and give you less "grunt" for pulling the plane around. This was likely the initial problem with the Sukhoi. Aerobatic planes simply do not fly fast very well, and the higher pitch prop wasn't efficient. Once you lowered the pitch and increased diameter the plane found it's sweet spot. (Lower top speed but more vertical pull.)
Just my opinion of course.
Dennis-
(Edited for spelling.)
08-07-2004, 11:34 AM
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Senior Member
RE: Matching Engine, Prop and Plane?????
To make it even more fun, all 12 x 6 props are not equal. One brand will do well and another will not satisfy. I did some fairly extensive prop testing on a particular control line airplane and engine combo and found that I was way off on my predictions of what would work best based on previous experience.
Jim
Jim
