patternprops
#1
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From: Evansville,
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looking to get into pattern flying. I see "pattern props" listed with a lot of pitch.. what are we looking for...slower acceleration but high top end speed. Is the blade configuration different for pattern???
Would this high pitch make for a hot landing speed also?
Would this high pitch make for a hot landing speed also?
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From: Oslo, NORWAY
Those big, high pitch props 17x13 16x12 etc are more about getting the engine RPM down than they are for speed.
There are very strict noise regulations in pattern thus most folks are say propping to get the engine to rev about, say 8000 RPM and less.
Because of ground clearance, larger diameter props can cuase problems, thus the only option is to increase pitch to decrease revs.
The engines used, those specifically for pattern are designed to deliver power at these low RPM's.
To get high speed you need high pitch, high RMP... Pylon racing style. 10x10 at 30,000RMP sort of thing. That'll get you there veryfast. but again you'll need specialist engines.
What type of plane, engine combo and effect are you after?
There are very strict noise regulations in pattern thus most folks are say propping to get the engine to rev about, say 8000 RPM and less.
Because of ground clearance, larger diameter props can cuase problems, thus the only option is to increase pitch to decrease revs.
The engines used, those specifically for pattern are designed to deliver power at these low RPM's.
To get high speed you need high pitch, high RMP... Pylon racing style. 10x10 at 30,000RMP sort of thing. That'll get you there veryfast. but again you'll need specialist engines.
What type of plane, engine combo and effect are you after?
#3
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From: Formosa, ARGENTINA
Unless you are going to be under noise regulations you really dont need to go with a stict pattern prop. Go with the prop that works best on your setup. I asked this question several months ago in the pattern forum and that is the answer I got.
The high pitch is not for speed like bla bla said. The newer style pattern plane designs are proof of that... the newer planes are not built with speed in mind.
I have a 90 sized pattern plane and use the old standby 14X6 prop.
The high pitch is not for speed like bla bla said. The newer style pattern plane designs are proof of that... the newer planes are not built with speed in mind.
I have a 90 sized pattern plane and use the old standby 14X6 prop.
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From: Locust Grove,
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What I understand about pattern is that the desire is to maintain a constant speed.
The higher pitch propellers are good for this.
In SA, you bleed off a LOT of energy with some of the maneuvers so you need a lot of thrust to recover.
For your higher landing speed, you do need less pitch or lower RPM.
What I do is to have an idle down setting that will keep the engine turning over while the plane is in the air but when it is on the ground, it is not fast enough to keep it going. It allows for great slow landings.
The higher pitch propellers are good for this.
In SA, you bleed off a LOT of energy with some of the maneuvers so you need a lot of thrust to recover.
For your higher landing speed, you do need less pitch or lower RPM.
What I do is to have an idle down setting that will keep the engine turning over while the plane is in the air but when it is on the ground, it is not fast enough to keep it going. It allows for great slow landings.
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From: Oslo, NORWAY
ORIGINAL: halflight
I have a Wide Boey 60 powered with an OS 1.20 Surpass. Started with a 15x8..went to a 15x6..still comes in really hot. Any advice appreciated.
I have a Wide Boey 60 powered with an OS 1.20 Surpass. Started with a 15x8..went to a 15x6..still comes in really hot. Any advice appreciated.
A great deal of people also land using spoilerons (Raised ailerons) to bleed of speed and get the plane down.
Secondly we're flying far, far further out than you would when you're sports flying, say 150-175m... thats give you plenty of time to loose speed/hight.
I think your problem is due to several thing. Slightly over powering the plane.The 1,20 surpass is a heavy engine, far,far heavier than say an OS .91FX which seens the norm in that plane, so you're over weight thus higher landing speed. Wrong prop...16dia would be better, wrong landing technique, to close in etc etc.
The good thing is that the answers simple.
If you're say, in your case, flying a up wind leg 100m out, at about the 60 deg mark, bring the engine down to 3rd throttle and make a 180deg turn to bring you back on the down wind leg ending 1/4 ish'throttle.
When the planes passed the end of the runway, 90deg turn in, fly straight desending at idle, as you approach the runway (I've now cut my engine) do a 90deg turn to line you up and aim to touch down infront.
Thats what we do. It'll give you plenty of time to bleed off speed!
When you use spoilerons you can cut that approach dramitically. You even have to carry engine to stop the plane comming down beyond the threashold.
Practice, experiment... it's fun.
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From: Formosa, ARGENTINA
ORIGINAL: Geistware
What I understand about pattern is that the desire is to maintain a constant speed.
The higher pitch propellers are good for this.
In SA, you bleed off a LOT of energy with some of the maneuvers so you need a lot of thrust to recover.
What I understand about pattern is that the desire is to maintain a constant speed.
The higher pitch propellers are good for this.
In SA, you bleed off a LOT of energy with some of the maneuvers so you need a lot of thrust to recover.
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From: Oslo, NORWAY
As I said above, because of the noise regs we need to get the RPM's down. you can do this with several factors : the prop dia' or pitch. The number of blades and the wide of the blade.
Because of the ground clearence, most have tended to go the pitch route. But recently due to electric, the newer tallbody designs and the availability of longer UC's many have also experimented with a larger dia' less pitch props to get the same effect.
What people have noticed is that because we tend to fly quite a long way out, using those low pitch props at our low RPM can cause the airplane to appear to be flying to slowly!
It just take to long to cover the same distance. Thus some have gone back to the higher pitch selection. Mind you we're not talking much here, for example: Those using a 17x12 may today be using a 18x10 and flying slightly slower and slightly closer than the did in the passed.
Because of the ground clearence, most have tended to go the pitch route. But recently due to electric, the newer tallbody designs and the availability of longer UC's many have also experimented with a larger dia' less pitch props to get the same effect.
What people have noticed is that because we tend to fly quite a long way out, using those low pitch props at our low RPM can cause the airplane to appear to be flying to slowly!
It just take to long to cover the same distance. Thus some have gone back to the higher pitch selection. Mind you we're not talking much here, for example: Those using a 17x12 may today be using a 18x10 and flying slightly slower and slightly closer than the did in the passed.



