Cox Engines Forum
You are not logged in! Please login or register.

Logged in members see NO ADVERTISEMENTS!


Propeller question Cox_ba12




Propeller question Pixel

Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Latest topics
» Half-A experiences at CL Clubs
by Yabby Yesterday at 5:05 pm

» Anybody's flying with Brodak 049?
by Ken Cook Yesterday at 12:48 pm

» Cox pt19 engine mount
by getback Yesterday at 12:16 pm

» piper l-4j wit cessna 150 wing miss monica tee dee .051 now
by davidll1984 Yesterday at 9:25 am

» Conquest Wanted
by 1Bad67 Yesterday at 8:43 am

» Pit Bull Terrier -
by rsv1cox Yesterday at 6:14 am

» Rustolium spray paint.
by Oldenginerod Yesterday at 4:12 am

» **VOTE-ON-THE-NEXT-COX-ENGINE-OF-THE-MONTH** (June 2021)
by balogh Yesterday at 1:18 am

» Jim Walker U-Reely and a Cox connection?
by rsv1cox Fri Jun 11, 2021 3:34 pm

» Jim Walker "Firebrand"...It Flys !!!!!
by Kim Thu Jun 10, 2021 9:25 pm

» What a friend gave me.
by batjac Thu Jun 10, 2021 9:18 pm

» Who made this throttle?
by davidll1984 Wed Jun 09, 2021 1:01 pm

Cox Engine of The Month
June-2021
balogh's

"Little Red Rooster"




PAST WINNERS
CEF Traveling Engine

Win This Engine!
Forum Store
CEF Ear Savers
Gallery


Propeller question Empty

Propeller question

Go down

Propeller question Empty Propeller question

Post  Cox International Mon May 10, 2021 12:03 pm

For buyers looking for a "pusher" prop, we offer this one, together with instructions on how to mount / run, so that leading and trailing edges perform in the proper direction:

https://coxengines.ca/propellers/cox--049-propeller-left-hand-pusher-5-x-3-5.html

Conversely, can any right-hand prop be mounted "hub-reversed" and run left-hand (pusher mode) without degrading performance?
Cox International
Cox International
Top Poster
Top Poster

Official Cox Dealer
Posts : 3093
Join date : 2011-08-08
Age : 63
Location : Williams Lake, BC, Canada

http://www.coxengines.com

Back to top Go down

Propeller question Empty Re: Propeller question

Post  davidll1984 Mon May 10, 2021 12:26 pm

I don't know about the different type of propeller that could offer better performance but I can give you something with the motors to use is the small modification I made to improve the performance with two trust washers the friction is greatly reduced resulting in less wear less friction possible to mix two types differing from one metal to one fenolic wit the tee dee engine two washer wil Not fit direct modification To crankcase and prop drive plate one washer One with a larger inside diameter to fit over the larger portion of the crankshaftPropeller question 16206610
davidll1984
davidll1984
Diamond Member
Diamond Member

Posts : 1375
Join date : 2020-02-12
Age : 36
Location : shawinigan

Back to top Go down

Propeller question Empty Re: Propeller question

Post  Marleysky Mon May 10, 2021 6:50 pm

Do ya like to read? If not, here’s some homework for ya!

https://journals.sagepub.com/doi/full/10.1177/1756829316638206

There are a couple of pictures just to keep you interested!!
Marleysky
Marleysky
Diamond Member
Diamond Member

2019 Supporter

2020 Supporter

2021 Supporter

Posts : 2982
Join date : 2014-09-28
Age : 68
Location : Grand Rapids, MI

Back to top Go down

Propeller question Empty Re: Propeller question

Post  Levent Suberk Tue May 11, 2021 5:55 pm

It works.


Last edited by Levent Suberk on Wed May 12, 2021 1:45 am; edited 1 time in total
Levent Suberk
Levent Suberk
Diamond Member
Diamond Member

Posts : 1228
Join date : 2017-12-24
Location : Turkey

Back to top Go down

Propeller question Empty Re: Propeller question

Post  1/2A Nut Tue May 11, 2021 10:29 pm

You can fly the prop as a puller with a reed engine.
The TD is limited to pusher only unless you have a left hand crank.

Small Cox Logo Thumbs Up
1/2A Nut
1/2A Nut
Top Poster
Top Poster

2019 Supporter

2021 Supporter

Posts : 3074
Join date : 2013-10-20
Age : 57
Location : Brad in Texas

Back to top Go down

Propeller question Empty Re: Propeller question

Post  dirk gently Wed May 12, 2021 3:29 am

@Cox International wrote:can any right-hand prop be mounted "hub-reversed" and run left-hand (pusher mode) without degrading performance?

I see no performance-related reason why it wouldn't work.
However, I don't like the idea of running the engine in the "wrong" direction, because that will have a tendency to loosen the prop screw while running, rather than tightening it when running in the "normal" direction. Not sure how much of a problem that would be in practice.
Obviously, running the engine "backwards" is only an option for reedies.
dirk gently
dirk gently
Gold Member
Gold Member

Posts : 425
Join date : 2012-02-03
Age : 38
Location : Poznań

Back to top Go down

Propeller question Empty Re: Propeller question

Post  Cox International Wed May 12, 2021 11:37 am

Not sure if the question has actually been answered to a degree of certainty.

The way we see it is that every propeller has a leading as well as a trailing edge. If the prop is mounted "hub-reversed" and run in the opposite direction, then the aerodynamics remain the same but one ends up with a "pusher" prop.

Of course TD engines would need a LH crank and there will be the "screw-coming-loose" issue.

Was just looking for a confirmation because we constantly get requests for pusher props.

Cox International
Cox International
Top Poster
Top Poster

Official Cox Dealer
Posts : 3093
Join date : 2011-08-08
Age : 63
Location : Williams Lake, BC, Canada

http://www.coxengines.com

Back to top Go down

Propeller question Empty Re: Propeller question

Post  Surfer_kris Wed May 12, 2021 12:16 pm

Most people may well prefer pusher props, as the running direction of the engine then stays the same.

Appart from the prop screw issue, there is also the need for a reverse spring starter and relearning how to flip the prop etc.
Surfer_kris
Surfer_kris
Diamond Member
Diamond Member

Posts : 1785
Join date : 2010-11-20
Location : Sweden

Back to top Go down

Propeller question Empty Re: Propeller question

Post  Cox International Wed May 12, 2021 12:54 pm

@Surfer_kris wrote:Most people may well prefer pusher props, as the running direction of the engine then stays the same.

Appart from the prop screw issue, there is also the need for a reverse spring starter and relearning how to flip the prop etc.

Yes, except that pusher props are almost non existing.

Also, we do sell the LH starter springs.
Cox International
Cox International
Top Poster
Top Poster

Official Cox Dealer
Posts : 3093
Join date : 2011-08-08
Age : 63
Location : Williams Lake, BC, Canada

http://www.coxengines.com

Back to top Go down

Propeller question Empty Re: Propeller question

Post  ajcoholic Fri May 14, 2021 8:07 pm

@Cox International wrote:Not sure if the question has actually been answered to a degree of certainty.

The way we see it is that every propeller has a leading as well as a trailing edge. If the prop is mounted "hub-reversed" and run in the opposite direction, then the aerodynamics remain the same but one ends up with a "pusher" prop.

Of course TD engines would need a LH crank and there will be the "screw-coming-loose" issue.

Was just looking for a confirmation because we constantly get requests for pusher props.


Yes, 100% if you mount a tractor prop backwards, and run the engine in the opposite direction, you have a pusher configuration. Also, I have run many reedies as pushers, and have never had the prop screw loosen. Ever.
ajcoholic
ajcoholic
New Member
New Member

Posts : 4
Join date : 2017-12-23

Back to top Go down

Propeller question Empty Re: Propeller question

Post  andrew Fri May 14, 2021 11:54 pm

@ajcoholic wrote:Yes, 100% if you mount a tractor prop backwards, and run the engine in the opposite direction, you have a pusher configuration.  Also, I have run many reedies as pushers, and have never had the prop screw loosen.  Ever.

Andrew --
Nice to see a name from the old RCU group showing up here.  Don't be a stranger.

The "other" Andrew
andrew
andrew
Diamond Member
Diamond Member

Posts : 1372
Join date : 2011-08-11
Age : 73
Location : Western Kentucky

http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM

Back to top Go down

Propeller question Empty Re: Propeller question

Post  Marleysky Sun May 16, 2021 3:26 pm

Marleysky
Marleysky
Diamond Member
Diamond Member

2019 Supporter

2020 Supporter

2021 Supporter

Posts : 2982
Join date : 2014-09-28
Age : 68
Location : Grand Rapids, MI

Back to top Go down

Propeller question Empty Re: Propeller question

Post  batjac Sun May 16, 2021 9:54 pm

@Cox International wrote:Conversely, can any right-hand prop be mounted "hub-reversed" and run left-hand (pusher mode) without degrading performance?

For all practical purposes, a prop doesn't care whether it's pushing or pulling.  The only real considerations of using a tractor prop in a reed engine as a pusher are 1) the air flow around the fuselage before getting to the prop, and 2) the drag on the drive plate against the crankcase.  As a tractor, it's in clean air and is most efficient.  As a pusher, it's in dirty air and not as efficient. As for the case drag, I don't know if the drag of the back of the prop hub in a pusher configuration is more or less than the drag of the crank hub against the face of the thrust bearing in the case.  But as for the prop itself, as long as the curve is forward, it's good to go.

The Dr. Doolittle Mark
batjac
batjac
Diamond Member
Diamond Member

2019 Supporter

2020 Supporter

Posts : 1975
Join date : 2013-05-22
Age : 58
Location : Portland, OR, USA

Back to top Go down

Propeller question Empty Re: Propeller question

Post  Sponsored content


Sponsored content


Back to top Go down

Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum