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-   -   Prop. Pitches (https://www.rcuniverse.com/forum/questions-answers-154/4876464-prop-pitches.html)

fzeller 10-16-2006 07:01 PM

Prop. Pitches
 
Howdy Folks

I think I have this right. If you have a 10-6 prop. and want more pull to get off the ground faster. You should go to a 11-5 prop. But I can not use a larger diameter because I am cutting grass with the prop now. So, I have to stay with a 10 inch prop. should I go with more pitch or less pitch? 10-5 or 10-7 or some other pitch.? As always, thanks for your help.
P.S. It is on a 40 O.S. Max. It that makes any difference.
Fred

Geistware 10-16-2006 07:48 PM

RE: Prop. Pitches
 
You have it right and you can go to bigger tires to get more ground clearence.
a 10-5 will give you more RPM and more pull due to the higher RPM of the propeller.

da Rock 10-16-2006 09:49 PM

RE: Prop. Pitches
 
If you really like the airplane, think about retrofitting taller landing gear.

Going to an 11" prop from a 10" prop only moves the prop tip 1/2" closer to the ground. To get that 1/2" back from larger tires, you're going to have to put 1" larger ones on the airplane. It's real easy to get a couple of inches from taller gear. And you get almost no more drag from longer gear whereas tires that're one inch bigger on a 40size plane are going to be obviously larger. Will you feel the difference? Probably not. But on a 40size airplane....... it's worth thinking about. You're already wanting more pull. So why do something that can get it but costs some of that pull getting it?

What's the airplane?

Have your gearlegs bent over time? You might get the height just by bending them down some. Even if they haven't flattened out from use.

Geistware 10-16-2006 10:23 PM

RE: Prop. Pitches
 
Bigger tires on grass will make the plane roll easier.
Bigger tires are not always more drag while on the ground.
From a weight standpoint, you can go with some of the foam tires which are very light.

fzeller 10-16-2006 11:14 PM

RE: Prop. Pitches
 
The plane is a Tower Hobbies trainer 40. I would like to make it a tail dragger, and throw the rubber bands away, and bolt the wing on. That being said, I read in another post that that is what another guy wanted to do, but he was told that because the rudder is above the elevator. It is very hard to mount a tail wheel on it. He was also told that because of the way the plane is built, it is also very hard to bolt the wing on. I guess I will have to live with it the way it is. Thanks Guys. Fred

carrellh 10-17-2006 03:02 PM

RE: Prop. Pitches
 
I don't have any photos but my brother and I assembled my Big Stik 60 as a tail dragger; and it has the same "rudder above the elevator" issue as your plane.

I didn't come up with this solution. I saw a description, and photos, somewhere on RCU.

I bought these pushrods at the LHS:
http://www2.towerhobbies.com/cgi-bin...?&I=LXK059&P=0
I have a 3/16" drill bit that's about a foot long, from Home Depot.

We attached the tail wheel bracket, determined the path for the pushrod, and used the long bit to drill an angled hole for the pushrod tube to exit the fuselage. Inside the fuselage we drilled a 3/16 hole in the former behind the rudder servo, next to the existing rudder pushrod tube. It took several tries to get the pushrod tube installed, then we ran the rod through the tube and hooked it up. The pushrod tube is only attached to anything at the ends. This would not be ideal for a control surface but it has not presented any issues just turning a wheel.

I don't know enough about the structure of your wing and fuselage to comment on converting to wing bolts.

lrtx1 10-17-2006 05:58 PM

RE: Prop. Pitches
 
I just made a set of gear wires for a tower trainer 40. Used 5/32 music wire. Installed bigger wheels, 3 1/4" rear 3" front. The stock gear is real flimsy and has probably bent on you over time. I used 11 X 5 the way it was stock off grass with no problems.

Layne


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