prop pitch question
06-11-2005 | 04:36 PM
#1
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From: Ridgefield, CT
prop pitch question
Hi
i am a begginer with planes, and have not purchased a plane yet, but i am looking at the flat foamies (arf), a 9x3.8 prop is recommended for a brushless system i am looking at. the only thing is that i would like to get some extra props...because i will crash. I just dont understand what the numbers mean...i think the 9 is the diamater/length of the prop, 9" in this case right?
but the second number, the pitch...what does that mean? is a pitch of 5 at a greater angle than a 3.8 or would 3.8 be steeper? would [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHHW8&P=0]these[/link] be fine for an Esskay outrunner?
thanks for your help!
Nick
i am a begginer with planes, and have not purchased a plane yet, but i am looking at the flat foamies (arf), a 9x3.8 prop is recommended for a brushless system i am looking at. the only thing is that i would like to get some extra props...because i will crash. I just dont understand what the numbers mean...i think the 9 is the diamater/length of the prop, 9" in this case right?
but the second number, the pitch...what does that mean? is a pitch of 5 at a greater angle than a 3.8 or would 3.8 be steeper? would [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHHW8&P=0]these[/link] be fine for an Esskay outrunner?
thanks for your help!
Nick
06-11-2005 | 04:52 PM
#2
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RE: prop pitch question
You are correct about the diameter and the second number is pitch in inches and in this case 3.8 inchs. What that means is this is the distance the propellor would move forward during one rotation of the prop operating in in a theoretical solid (in otherwords no loss of efficiency due to slippage and other factors).
A lower pitched propellor say a 5P for example is also sometines called a fine pitch prop. A higher pitched prop say a 6P is sometimes called a course prop. Just like threads on a bolt.
John
A lower pitched propellor say a 5P for example is also sometines called a fine pitch prop. A higher pitched prop say a 6P is sometimes called a course prop. Just like threads on a bolt.
John
06-12-2005 | 12:15 AM
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RE: prop pitch question
The pitch number does equal the number of inches the prop will move through a solid material in one revolution. This is theory, since the prop slips in the air. GIVEN THE SAME RPM, more pitch, less diameter equals more speed and less pull. Conversely, more diameter, less pitch equals more pull, less top speed.
Dr.1
Dr.1
06-12-2005 | 06:59 AM
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From: GeelongVictoria, AUSTRALIA
RE: prop pitch question
Added to that is the matter of Torque.
The taller the prop (diameter) the more torque you will get. This gives you Climbing power. An 11 x 6 prop will give less speed than a 10 x 7, but it will give the model a better climb rate.
It's all matter of what you want the model to do.
I fly electrics as well as glow and on my favourite electric I chose between a 6 x 4 or a 5.25 x 4.75. dependig upon what I want the model to do and where I am flying it.
The latter prop gives more speed but less overall flying time on the battery.
When flown with the former prop, the model is slower in a straight line, but gives better climb power and I can get almost 5 or 6 minutes more flight time from the same pack.
The taller the prop (diameter) the more torque you will get. This gives you Climbing power. An 11 x 6 prop will give less speed than a 10 x 7, but it will give the model a better climb rate.
It's all matter of what you want the model to do.
I fly electrics as well as glow and on my favourite electric I chose between a 6 x 4 or a 5.25 x 4.75. dependig upon what I want the model to do and where I am flying it.
The latter prop gives more speed but less overall flying time on the battery.
When flown with the former prop, the model is slower in a straight line, but gives better climb power and I can get almost 5 or 6 minutes more flight time from the same pack.
