Cox Engines Forum
You are not logged in! Please login or register! Guests are limited to posting in the "General Questions (Guest Posting Allowed)" section only. Becoming a member is fast, easy and FREE!


Prop swap for Babe Bee Babe_b10
Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Latest topics
» Around the pole flying
by F4D Phantom II Today at 10:10 pm

» Follow The World's Smallest Traveling Engine!
by dckrsn Today at 9:57 pm

» Parts built RR-1
by Tee Bee Today at 7:37 pm

» RC plane for TeeDee 010 and 020 engines
by balogh Today at 5:53 pm

» Non Slip Screwdriver Tip
by Levent Suberk Today at 4:38 pm

» Laping tool
by Ken Cook Today at 8:37 am

» RC build of a Guillows Porter PC-6 for .020 Pee Wee
by Daligh Today at 5:37 am

» Cylinder Porting
by coxaddict Today at 3:25 am

» Guilow edge g-540 rc
by davidll1984 Yesterday at 7:50 pm

» Cox engine .049 r/c & COX FUN MODEL
by MauricioB Yesterday at 1:03 pm

Cox Engine of The Month
September-2020
sosam117's

"Traded an electric charger for this "Complete" (original) Cox Thimble Drome Olympic .15 engine. Right corner is photo as received."



PAST WINNERS
CEF Traveling Engine

Win This Engine!
Gallery


Prop swap for Babe Bee Empty

Prop swap for Babe Bee

Go down

Prop swap for Babe Bee Empty Prop swap for Babe Bee

Post  OhBee on Mon Mar 16, 2020 5:43 pm

6x3 to 5x3....both Cox props. What is going to be the difference on a Babe Bee ?Prop swap for Babe Bee 20200315
OhBee
OhBee
Gold Member
Gold Member

Posts : 355
Join date : 2016-03-23
Age : 69
Location : Minnesota

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  Mark Boesen on Mon Mar 16, 2020 5:52 pm

Diameter for RPM, pitch for speed, rule of thumb, smaller prop will turn higher RPM and net more speed. Larger prop would generate more thrust, less speed.
Mark Boesen
Mark Boesen
Top Poster
Top Poster

Posts : 3878
Join date : 2011-09-01
Age : 62
Location : Rockford, Il

http://groups.yahoo.com/group/049Collectors/

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  OhBee on Mon Mar 16, 2020 5:59 pm

Thats what I thought...but wouldn't the smaller one have more rpm..LESS speed?  Which would you suggest for this  old Re-beginner  on a Lil Satan?  Even an .049 looks like overkill on this light little bugger!.....doesn't thrust also have a bearing on speed?
OhBee
OhBee
Gold Member
Gold Member

Posts : 355
Join date : 2016-03-23
Age : 69
Location : Minnesota

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  944_Jim on Mon Mar 16, 2020 6:44 pm

OhBee,
I'm not trying to confuse you, I promise!

The larger prop will help pole-vault the model when it dead-sticks into Terra Firma.

Try them both.

Remember to get the engine started, and hold it for about 20 seconds. That is 20 seconds less time you will spend spinning in circles going "Oh my...Oh my...splat."

When you go to fly for the first time, keep in mind the quick "march to the left." It helps minimize dizziness by converting "spinning left" into "stepping always left fast. I found tracing a 5 foot circle to be a lot of cardio workout, but it beat falling down with the model still up. If/When you get tired of stepping left, go back to spinning left.

If you stick with it long enough, you will find the dizzies soften quite a bit. My dizzies disappear after several outings, but always come back after a seasonal break.
944_Jim
944_Jim
Platinum Member
Platinum Member

2019 Supporter

Posts : 871
Join date : 2017-02-08
Age : 55
Location : NE MS

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  OhBee on Mon Mar 16, 2020 7:14 pm

Why does everyone think I'm going to go splat!?  I used to do this every weekend!.......54 yrs. Ago!      Wink
OhBee
OhBee
Gold Member
Gold Member

Posts : 355
Join date : 2016-03-23
Age : 69
Location : Minnesota

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  944_Jim on Mon Mar 16, 2020 7:33 pm

I dunno...my break was shorter, albeit still decades long. I'm hoping for the best for you, and invested in your glorious return!

And it isn't everyone thinks this...just the ones that took big breaks and did it again (all the old f@rt$).

If you can't find the #2 screws, I'll snailmail a few your way.
944_Jim
944_Jim
Platinum Member
Platinum Member

2019 Supporter

Posts : 871
Join date : 2017-02-08
Age : 55
Location : NE MS

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  OhBee on Mon Mar 16, 2020 7:49 pm

What are lap times for one of these on 35' lines? 3-4 sec? At 3 secs. thats 40 laps in a two minute burn!....I'm already dizzy!     🤪
OhBee
OhBee
Gold Member
Gold Member

Posts : 355
Join date : 2016-03-23
Age : 69
Location : Minnesota

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  ticomareado on Mon Mar 16, 2020 8:04 pm

Put the prop on backwards to kill efficiency by 15 to 20 % if you are afraid of your little spin monster.
ticomareado
ticomareado
Account Under Review

Posts : 1082
Join date : 2013-10-03
Location : NC

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  944_Jim on Mon Mar 16, 2020 8:51 pm

Somewhere I saw a disk that would be mounted between prop and backplate. That disk basically blocks off half of the prop blade effective area thus reducing thrust. I think details can be found on Outerzone in the plan that looks like a Venetian blind for a wing-thing.

Yup here:
https://outerzone.co.uk/plan_details.asp?ID=9680


Last edited by 944_Jim on Mon Mar 16, 2020 10:11 pm; edited 1 time in total (Reason for editing : Found the site)
944_Jim
944_Jim
Platinum Member
Platinum Member

2019 Supporter

Posts : 871
Join date : 2017-02-08
Age : 55
Location : NE MS

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  OhBee on Mon Mar 16, 2020 11:05 pm

How can anything fly forward with a prop on backwards? A propellar is a screw. I didn't start with a trainer when I was a kid...I don't guess I need one now! I taught myself to fly RC four years ago. I havn't crashed one for 3 yrs...and even then they weren't destructive crashes...just cosmetic. I guess I can handle a plane with ONE control surface on strings! ......as long as its a flyable airframe....which has already been proven.

OhBee
OhBee
Gold Member
Gold Member

Posts : 355
Join date : 2016-03-23
Age : 69
Location : Minnesota

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  Mark Boesen on Mon Mar 16, 2020 11:48 pm

OhBee wrote:Thats what I thought...but wouldn't the smaller one have more rpm..LESS speed?  Which would you suggest for this  old Re-beginner  on a Lil Satan?  Even an .049 looks like overkill on this light little bugger!.....doesn't thrust also have a bearing on speed?

No, more RPM, more speed. Yes...thrust is a must or your patterns a bust, just kidding, but kinda true (old ukie saying) a larger dia. would offer more thrust at cost of RPM. an engine has just so much power, you can tailor it some with prop, compression, fuel, etc.

on a 1/2a your kinda splitting hairs, i'd go 6x3 for starters, once you get comfortable add some rpm with 5" prop.

Flipping prop backward, the angle of attack is still the same, but you've lost efficiency.
Mark Boesen
Mark Boesen
Top Poster
Top Poster

Posts : 3878
Join date : 2011-09-01
Age : 62
Location : Rockford, Il

http://groups.yahoo.com/group/049Collectors/

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  OhBee on Tue Mar 17, 2020 1:23 am

Thanks Mark!   It's coming together and making more sense now. I've always been an airplane nut...but NOT an aeronautical engineer!
OhBee
OhBee
Gold Member
Gold Member

Posts : 355
Join date : 2016-03-23
Age : 69
Location : Minnesota

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

Post  ticomareado on Tue Mar 17, 2020 6:00 am

"How can anything fly forward with a prop on backwards? "

The prop produces trust in a fluid medium (air in this case) from RPMs, blade pitch and airfoil of the blade. When you put prop on backwards you are only reversing the blade's "airfoil effect". Now if you start the engine backwards with prop on backwards, you've got 100% bass-ackwards action.
ticomareado
ticomareado
Account Under Review

Posts : 1082
Join date : 2013-10-03
Location : NC

Back to top Go down

Prop swap for Babe Bee Empty Re: Prop swap for Babe Bee

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