Prop swap for Babe Bee

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,
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.

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

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.

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!     🤪

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

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

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 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.

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

"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.