prop help
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prop help
Hey guys.. I need some advise on a prop for this plane. I've been using a 10/7 on it, and its been super fast. Its called a critter. The wing is about ten years old or so. when I used to fly it then the plane would take off from your hand real easy.. Now with this prop tho its fast it takes along time to get up to speed, and you have to give it a pretty good toss into the air...I don't reamember what motor I had on it before, but it was about the same size. Which prop would still give me some good top speed, but maybe give me some more tourque to help get it flying easier? The motor is a OS AX 46. I hate to give up any speed, but shes has to be easy to get in the air too.
THANKS FOR THE HELP.
JB
THANKS FOR THE HELP.
JB
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RE: prop help
ORIGINAL: JEREMYB
Hey guys.. I need some advise on a prop for this plane. I've been using a 10/7 on it, and its been super fast. Its called a critter. The wing is about ten years old or so. when I used to fly it then the plane would take off from your hand real easy.. Now with this prop tho its fast it takes along time to get up to speed, and you have to give it a pretty good toss into the air...I don't reamember what motor I had on it before, but it was about the same size. Which prop would still give me some good top speed, but maybe give me some more tourque to help get it flying easier? The motor is a OS AX 46. I hate to give up any speed, but shes has to be easy to get in the air too.
THANKS FOR THE HELP.
JB
Hey guys.. I need some advise on a prop for this plane. I've been using a 10/7 on it, and its been super fast. Its called a critter. The wing is about ten years old or so. when I used to fly it then the plane would take off from your hand real easy.. Now with this prop tho its fast it takes along time to get up to speed, and you have to give it a pretty good toss into the air...I don't reamember what motor I had on it before, but it was about the same size. Which prop would still give me some good top speed, but maybe give me some more tourque to help get it flying easier? The motor is a OS AX 46. I hate to give up any speed, but shes has to be easy to get in the air too.
THANKS FOR THE HELP.
JB
MJD
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RE: prop help
Propping for "torque" [known as thrust] is opposite of propping for speed, but sometimes you find a prop that puts the engine into it's sweet spot. I think a 9x7 or a 9x8 is universally the best for .45-50 powered planes in this size range. Like MJD says, a lot depends on how much this sucker weighs.
The heavier the plane, the fewer the choices you will have for props.
The heavier the plane, the fewer the choices you will have for props.
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RE: prop help
ORIGINAL: combatpigg
Propping for "torque" [known as thrust] is opposite of propping for speed, but sometimes you find a prop that puts the engine into it's sweet spot. I think a 9x7 or a 9x8 is universally the best for .45-50 powered planes in this size range. Like MJD says, a lot depends on how much this sucker weighs.
The heavier the plane, the fewer the choices you will have for props.
Propping for "torque" [known as thrust] is opposite of propping for speed, but sometimes you find a prop that puts the engine into it's sweet spot. I think a 9x7 or a 9x8 is universally the best for .45-50 powered planes in this size range. Like MJD says, a lot depends on how much this sucker weighs.
The heavier the plane, the fewer the choices you will have for props.
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RE: prop help
ORIGINAL: combatpigg
Sometimes squirrelly launches are due to inadequate fin area. A "thrusty" prop is a bandaid solution.
Sometimes squirrelly launches are due to inadequate fin area. A "thrusty" prop is a bandaid solution.
MJD
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RE: prop help
Those fins look marginal. Obviously they work, but I would make another pair that are swept to the rear. A pair of little tip fins will work wonders, too. You gotta figure that this plane should be able to do 100 or more with a .45.......guys with flying wings have been hitting 100 mph with 1 HP motors since before I was born.
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RE: prop help
OK, thanks for everyones help. the plane right now moves well over 100mph.. I did weigh it tonight, and she is 4 1/2 lbs empty. The wing is 48" long. Yes she does the weeble wobbles until she gets going. I should also mention that Sunday was the 1st day for the plane and the motor. I ran about 1/2 gallon throught it. So she still is alittle rich. I'll lean her out next time I go, and see what she does then. some one suggested a 9x7 or a 9x8?? seams small, but I haven't had a speed plane in a long time... I'll try a 10/6, but what do you all think about the 9x7 or a 9x8? any thoughts
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RE: prop help
ORIGINAL: JEREMYB
OK, thanks for everyones help. the plane right now moves well over 100mph.. I did weigh it tonight, and she is 4 1/2 lbs empty. The wing is 48" long. Yes she does the weeble wobbles until she gets going. I should also mention that Sunday was the 1st day for the plane and the motor. I ran about 1/2 gallon throught it. So she still is alittle rich. I'll lean her out next time I go, and see what she does then. some one suggested a 9x7 or a 9x8?? seams small, but I haven't had a speed plane in a long time... I'll try a 10/6, but what do you all think about the 9x7 or a 9x8? any thoughts
OK, thanks for everyones help. the plane right now moves well over 100mph.. I did weigh it tonight, and she is 4 1/2 lbs empty. The wing is 48" long. Yes she does the weeble wobbles until she gets going. I should also mention that Sunday was the 1st day for the plane and the motor. I ran about 1/2 gallon throught it. So she still is alittle rich. I'll lean her out next time I go, and see what she does then. some one suggested a 9x7 or a 9x8?? seams small, but I haven't had a speed plane in a long time... I'll try a 10/6, but what do you all think about the 9x7 or a 9x8? any thoughts
There is the outside chance that a 9-7 for example may bring the engine up the horsepower curve a bit and help, but in general lowering diameter is counterintuitive to launch problems. And typically a decent Schneurle .46 on a 10-7 pulls pretty hard off the starting line. Shave 8-16 oz off that airframe and try a 9x7 or 9x8 and you could see quite a few more mph.
The long wings have higher inertial moments than equivalent stubbies - something like that anyway - meaning I think they make the fins work pretty hard at low airspeeds and esp. with the typical upsets after a hand launch. If the wings are an over-contributor to the all up weight, then this makes a lot of sense. If the wings are light, and there is a lot of mass in the fuselage pod instead, then it doesn't jive so well. Where is the CG?
MJD
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RE: prop help
ORIGINAL: JEREMYB
The cg is at 2". Most of the weight is in the wings. A good section of the middle is figerglassed.
The cg is at 2". Most of the weight is in the wings. A good section of the middle is figerglassed.
MJD
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RE: prop help
ORIGINAL: JEREMYB
the cord is 12". Once up to speed.. she is very stable.. flys like shes on rails.
the cord is 12". Once up to speed.. she is very stable.. flys like shes on rails.
MJD