Making propellers

Bitconnect
Member
Member
Posts: 27
Joined: February 24th, 2018, 9:23 pm
Division: C
State: NH

Re: Making propellers

Postby Bitconnect » January 9th, 2019, 6:42 pm

Yeah, I'm going to cut blades from cups, use carbon fiber for spars, and use yellow plastic tubing for the pitch adjustment part. I'm gonna try to make it lighter than 2 grams but I'll see.

Bitconnect
Member
Member
Posts: 27
Joined: February 24th, 2018, 9:23 pm
Division: C
State: NH

Re: Making propellers

Postby Bitconnect » January 9th, 2019, 8:01 pm

Sadly, my cups are too small. Im going to cut my blades from a cylinder of plastic from a soda can. The bottle does not taper like what you're supposed to cut blades out of, but I've read that cylinders can also be used.

jander14indoor
Member
Member
Posts: 1510
Joined: April 30th, 2007, 7:54 am
State: -

Re: Making propellers

Postby jander14indoor » January 10th, 2019, 11:46 am

If you want larger pitch changes on Ikara props, careful, very localized application of heat can avoid the stress damage others have mentioned. Also very permanent. If you do it in a jig, easy to control accuracy.
You risk melting, but you'll now that right away.
At one point there was a video, but I wasn't able to find it with a short search. Been a lot of years since I last saw it.

Jeff Anderson
Livonia, MI

torqueburner
Member
Member
Posts: 64
Joined: January 8th, 2010, 11:41 am
Division: C
State: PA

Re: Making propellers

Postby torqueburner » January 17th, 2019, 8:00 am

jander14indoor wrote:If you want larger pitch changes on Ikara props, careful, very localized application of heat can avoid the stress damage others have mentioned. Also very permanent. If you do it in a jig, easy to control accuracy.
You risk melting, but you'll now that right away.
At one point there was a video, but I wasn't able to find it with a short search. Been a lot of years since I last saw it.

Jeff Anderson
Livonia, MI


We used to do it the way that Jeff mentions, by heating the spar. I have the video he mentions; pm me with your email address and I'll send you a copy.

Recently we have been making a hub from a 2 cm piece of 5/32" polystyrene tubing (Evergreen #225). Round off the ends of the spars a bit and you get a snug fit that can be easily repitched, then held in place with a bit of Ambroid or Duco cement.

Dave Drummer
Kutztown, PA

jander14indoor
Member
Member
Posts: 1510
Joined: April 30th, 2007, 7:54 am
State: -

Re: Making propellers

Postby jander14indoor » January 18th, 2019, 10:46 am

I've done the same using tissue tubes for the center of the spar. I inserted a small balsa dowel for the center 5 mm or so of the tube where the wire axis ran through it for strength and left the outer 5 mm or so open to insert spars with blades already glued on. Then set pitch with a gage. If its tight enough, no glue needed to lock in place.

Jeff Anderson
Livonia, MI

jinhusong
Member
Member
Posts: 82
Joined: March 16th, 2017, 3:34 pm
Division: C
State: CA
Location: Bay Area

Re: Making propellers

Postby jinhusong » February 2nd, 2019, 5:12 pm

Hi,

We bought 5/32" polystyrene tubing (Evergreen #225) and playing with 0.020" musical wire.

How to make the perfect hole on the tube, and what is the perfect hole? We tried directly use the musical wire, a needle.

Maybe tight is OK? There is no relative movement between the axis and the propeller during flying.

Another question, how the axis will transfer the torque to the propeller? Currently we just bend the wire like a hook (another bend after the 90 degree bend. It works but want to know how the professionals are doing it.

Do we need to do a freewheel on it?

Thanks in advance for your help,

Jinhu

jander14indoor
Member
Member
Posts: 1510
Joined: April 30th, 2007, 7:54 am
State: -

Re: Making propellers

Postby jander14indoor » February 2nd, 2019, 6:35 pm

You have it on transferring torque. For this kind of indoor flying you don't need, or even want freewheeling. Ideal indoor flight will be powered throughout the whole time aloft.

Free wheeling is only used for outdoor flight where the idea is to maximize altitude to catch lift.

Jeff Anderson
Livonia, MI

jinhusong
Member
Member
Posts: 82
Joined: March 16th, 2017, 3:34 pm
Division: C
State: CA
Location: Bay Area

Re: Making propellers

Postby jinhusong » February 2nd, 2019, 10:21 pm

jander14indoor wrote:You have it on transferring torque. For this kind of indoor flying you don't need, or even want freewheeling. Ideal indoor flight will be powered throughout the whole time aloft.

Free wheeling is only used for outdoor flight where the idea is to maximize altitude to catch lift.

Jeff Anderson
Livonia, MI


Hi Jeff, Thanks.

We will try to use the blades from Ikara and put them into the tube to play with pitch, just like Dave did.

When we have time, we want to make our own propeller with larger size.

Best,

Jinhu

User avatar
klastyioer
Member
Member
Posts: 209
Joined: April 22nd, 2018, 4:46 pm
Division: C
State: PA

Re: Making propellers

Postby klastyioer » February 18th, 2019, 9:34 am

im researching this too cause im new to making wood props
but start on page 94
the page jeff provided is helpful as well (page 4 wright stuff c)
but 94 is easier to comprehend for begs.

https://indoornewsandviews.files.wordpr ... f-inav.pdf
honestly, it's not about the medals. go out there and have fun. make progress, learn a few things, have one heck of a time, because that's all that matters.
---
Member of the Builder Cult >:)

NigerianScammer
Member
Member
Posts: 7
Joined: February 19th, 2019, 1:09 pm

Re: Making propellers

Postby NigerianScammer » February 19th, 2019, 1:23 pm

But wouldn’t wood not be very good for flare propellers because it won’t be able to change pitch?

User avatar
CrayolaCrayon
Member
Member
Posts: 160
Joined: October 25th, 2017, 8:24 am
Division: C
State: PA
Location: Flight Level 000
Contact:

Re: Making propellers

Postby CrayolaCrayon » February 19th, 2019, 1:40 pm

NigerianScammer wrote:But wouldn’t wood not be very good for flare propellers because it won’t be able to change pitch?


Why can't you change the pitch on a wood prop? If you make the hub right, sure you can.
"Better to remain silent and be thought a fool than to speak out and remove all doubt." - Abraham Lincoln

Image

User avatar
klastyioer
Member
Member
Posts: 209
Joined: April 22nd, 2018, 4:46 pm
Division: C
State: PA

Re: Making propellers

Postby klastyioer » February 20th, 2019, 8:22 am

CrayolaCrayon wrote:
NigerianScammer wrote:But wouldn’t wood not be very good for flare propellers because it won’t be able to change pitch?


Why can't you change the pitch on a wood prop? If you make the hub right, sure you can.


by hub do u mean tissue tube that is the like connector for the spars and the link to the hook?
honestly, it's not about the medals. go out there and have fun. make progress, learn a few things, have one heck of a time, because that's all that matters.
---
Member of the Builder Cult >:)

NigerianScammer
Member
Member
Posts: 7
Joined: February 19th, 2019, 1:09 pm

Re: Making propellers

Postby NigerianScammer » February 20th, 2019, 6:25 pm

CrayolaCrayon wrote:
NigerianScammer wrote:But wouldn’t wood not be very good for flare propellers because it won’t be able to change pitch?


Why can't you change the pitch on a wood prop? If you make the hub right, sure you can.


I mean in flight. The idea of the flare prop is that it changes pitch mid flight, but with a wooden prop it won’t have that tendency

coachchuckaahs
Member
Member
Posts: 188
Joined: April 24th, 2017, 9:19 am
Division: B
State: NM

Re: Making propellers

Postby coachchuckaahs » February 20th, 2019, 9:16 pm

NigerianScammer wrote:
CrayolaCrayon wrote:
NigerianScammer wrote:But wouldn’t wood not be very good for flare propellers because it won’t be able to change pitch?


Why can't you change the pitch on a wood prop? If you make the hub right, sure you can.


I mean in flight. The idea of the flare prop is that it changes pitch mid flight, but with a wooden prop it won’t have that tendency


The Ikara props flex primarily in the blade. Many built props, such as the Gowen hub, torsionally flex in the spar material. Some may flex in both. Yes, sand balsa thin enough it will flex (but also can be more fragile). Look at the flaps on the ELG gliders.

The flaring prop brings a number of new variables into the mix. You will want to take accurate data on the entire flight (altitude on each circle) in order to fully appreciate what a change in a variable (such as torsional stiffness) does. You may also find that the shape of the blade not only affects the aero of the prop, but also the effective stiffness.

We have been working with flaring props for 4 years now, primarily because our State event has been in a 19' ceiling. Our log book has about 16 columns, plus a notes section, and more than a few columns are related to the design, measurements, and performance of the prop. Good data is critical to understanding and moving forward.

Know that as the prop flexes, the pitch increases. Depending on your stiffness, you may need to have a lower static pitch than previously used on a non-flaring prop, and the pitch will go up in flight.

Coach Chuck

User avatar
klastyioer
Member
Member
Posts: 209
Joined: April 22nd, 2018, 4:46 pm
Division: C
State: PA

Re: Making propellers

Postby klastyioer » February 21st, 2019, 7:30 am

which wood size should i use like which one is most ideal for a ff kit like plane
im currently just experimenting with 1/32 but i have yet to actually test it in flight
i was wondering if i should step up to 1/16 and sand lightly but i dunno
honestly, it's not about the medals. go out there and have fun. make progress, learn a few things, have one heck of a time, because that's all that matters.
---
Member of the Builder Cult >:)


Return to “Wright Stuff C”

Who is online

Users browsing this forum: No registered users and 1 guest