Just a question

[Colt17752]

Okay so I really like the idea of making things move by thrust.

My first experiment was attaching fireworks rockets to a fan. Yes, I made a rocket powered fan, I estimated the thing to be spinning about 456 mph (I don't know how many rpm's that would be)

So now for the question, I have a black and decker drill which puts out about 2500 rpm's. Attached to it are 3 tongue depressors (glued together using typical wood glue) used to form 2 propellers that are 7 and 3 quarter inches long from shaft and they are 3/4ths of an inch wide. I'm guessing the weight of the drill itself is about 12 pounds. What would I have to do to be able to make the propellers actually be able to pull the drill in any direction it is pointed?

 

[Funkworks]

Can you lift the drill by the tongue depressors? Either way, weighing the drill would reveal a critical piece of information.

Also, tongue depressors have a rectangular profile. To maximize the lift-to-drag ratio, their profile needs to be closer to an airfoil shape, otherwise a lot of energy is wasted moving and heating air. So get ready for some sanding!

Also, if you were to succeed, the thing would fly out of control because it's not balanced and unguided, so people and stuff in the area need protection.

Also, this isn't rocketry.

That's all I have for now. Cheers!

 

[tim cubbedge]

you probably won't get too much help here. what you are attempting doesn't even sound safe.

 

[KennB]

You probably need to get some practical technical experience under your belt and come back here when you have a question pertaining to model rocketry.

I would be interested in knowing how you estimated the "spinning" speed of the fan. It's pretty basic math to determine the rpm if you know the speed at a radius from the axis of rotation.

Also, please provide a sketch to show how you could glue together three tongue depressors and come up with two propellers. The world wants to know.

 

[neil_w]

The world wants to know.

Does it really?

 

[Colt17752]

Oh I know it's not rocketry, there's not any other forums to my knowledge that are so openly direct.

And it's not like I want the thing doing 100mph lol across the back yard. The thing would be secured, just trying to get some speed going to where I feel some sort of tugging by it.

Anyway thanks for the answers everyone.

 

[Colt17752]

You probably need to get some practical technical experience under your belt and come back here when you have a question pertaining to model rocketry.

I would be interested in knowing how you estimated the "spinning" speed of the fan. It's pretty basic math to determine the rpm if you know the speed at a radius from the axis of rotation.

Also, please provide a sketch to show how you could glue together three tongue depressors and come up with two propellers. The world wants to know.

The way I managed to get three tongue depressors to work as two propellers is with one of the depressors fixed directly to the "nose cone" then gluing the other two depressors at opposite ends.

I'm aware that I don't have the tools but I'm working with what technology I have at my hands.

 

[Hangfire]

Start out with something like this.

 

[Colt17752]

been there done that. It's on my bucket list to build a jet engine one day.

 

[NateB]

Start with this site and find the link for a popsicle stick monocopter. https://www.artapplewhite.com/free/index.html

He shows you how to make a basic wing for a fun project that has higher chance of success than what you are trying.

Here is a primer on thrust generated by a propeller.
https://www.grc.nasa.gov/www/k-12/airplane/propth.html. And here is a chart showing power and the type of propeller needed for different weights of RC airplanes. https://hackermotorusa.com/resources/rc-brushless-motor-application-guide/

 

[dr wogz]

Go to RC Universe, and ask there.

https://www.rcuniverse.com/forum/?fh=1
they deal more with "spinning wings" than just chemicals burning under pressure

 

[cerving]

Looks like it's been done already...

 

[Cape Byron]

Looks like it's been done already...

Wow! Nice long burn.

 

[o1d_dude]

Looks like it's been done already...

Looks like they used a Chute Release...

 

[Greg Furtman]

Looks like it's been done already...

Now that looks like a lot of fun.

 

[Hooked On Rockets]

Looks like it's been done already...

Looks to me like a successful 3rd world Level2 certification flight!
CONGRATS!!!!!!

 

[neil_w]

Wow! Nice long burn.

That is the thing that always amazes me in these girandola videos... those are large motors with incredibly long burns.

 

[lakeroadster]

.... I have a black and decker drill which puts out about 2500 rpm's. ...
.... I'm guessing the weight of the drill itself is about 12 pounds ....

Let's see a photo of that drill... 'cause the likelihood of 2500 rpm's and/or 12 lbs being correct is slim and none.

As a point of ref. model airplane motors spin 10,000 - 12,000 rpm.

 

[boatgeek]

Let's see a photo of that drill... 'cause the likelihood of 2500 rpm's and/or 12 lbs being correct is slim and none.

As a point of ref. model airplane motors spin 10,000 - 12,000 rpm.

Aw, c'mon! It might be a 1/2" drive Milwaukee mag drill built for drilling big holes in thick metal!

 

[NateB]

That is the thing that always amazes me in these girandola videos... those are large motors with incredibly long burns.

Usually, they are BP end burners with some other metals added for effect or separate gerbs for effect. I've seen some made with whistle motors which were fantastic. The guys that make them spend a lot of time on a test stand dialinging in consistent motors and it shows when they successfully launch a big one.

‐‐------

If the OP is still around, these guys used 4 box fans to build a quadcopter. They did replace the motors.