Propeller Backpack Part 2 

I'm gonna weld myself an aluminum frame with a prop guard! Then maybe people will stop treating me like I haven't thought about risk and safety yet :) However increasing efficiency with a duct only works in extreme cases where the propeller design would otherwise be really really inefficient, such as a prop with a whole lot of really fat and short blades spinning really really fast. In that case the duct has to be designed really well with very tight clearances. A long skinny exposed prop will always be more efficient

Thanks! It's amazing what I can do when it's just me and a camera without having to actually do the thing. Now I really want a flying camera rig

Haha yes!!

Is that even a thing outside Sweden?

I agree, you've had what equates to a quantum leap in production quality. Nice work. :)

iforce2d it's pushing, not pulling. I'd trust it.

@Peter: Yes, this is a thing. Electric paramotors exist, and are freaky cool! The down side is in the power density of the batteries. Liquid fuel, at least for now, is king when it comes to power density. I am a free flight pilot, but would love an electric booster to get me off the ground. (>*

Sample Textᴴᴰ hahaha Imagine samm with a jet engine coming out of his ass😂😂😂

Buy me a jetcat and I'll do it lol

Samm Sheperd okay, i'l start a go fund me campaign, I think this is going to be huge!

Agree.

Shroud yes. Duct no

Samm Sheperd you should put a gas motor on that thing.

You should put double jet turbines! *And to each side.* Your chest is blocking most of the air flow for the propeller. You're creating a void behind your back that's not good for aerodynamics. That's why fast speed cyclists helmets have that weird drop shape. Changing something so small can really help efficiency.

The centrifugal fan is difficult to make efficient for thrust purposes. High static thrust is easier with a big prop.

Samm Sheperd Yes, you're absolutely right: the axial fans have higher flow rate than centrifugal, the only benefit of those is higher compression ratio. The snail shroud will be bulky, comparing to neat cage around the propeller. The only benefit of the twin centrifugal propulsors may be their steampunky look.

Not trying to make a propeller bike, just a propeller backpack

The stunt double in this part is my friend, I was radio controlling him :) We did extensive "what if" testing and planning

and what speed aprox he reached ??? what would be the batterie mileage ??

I hate to rain on your parade, and I would very much like to see the figures myself, but I suspect the efficiency of this setup is going to suck relative to a similar electric bike.

Of course we could always try more power... :3

That wouldn't be nearly as ridiculous though :) And also kinda difficult and more permanent

Eirik Strand overheating?

This esc features: • Over heat, low voltage, lost signal and power arm protection • Data logging such as temperature, voltage, current, and RPM • Advanced governor mode and smooth start up perfect for helicopters Maybe try to find out what went wrong? I would really like to buy a big motor myselves, but stuff always breaks and I'm tired of it

I did get a whiff of electrical smoke when I first investigated. Really pisses me off though since it didn't even get hot and I don't know what happendl

Next video I will have a safer frame

That was the plan. Coming in a later episode

Awesome

Yea thrust angle was a constant difficulty because it is natural to hunch your back when going fast. I was doing it a lot with the skis earlier too.

Samm Sheperd you should put it on a hinge with a flight controller or something to keep it level

There are several videos where people make and use single bladed propellers. just search for it. It is true that you can achieve greater efficiency using a single blade. This is because in order to apply the same load to the motor even though you have half the propeller, you can increase the blade length. A longer blade has a higher aspect ratio and thus has greater efficiency. You can also imagine the blade has a greater disc area and affects more air. Simply put: Inefficient = Taking a small amount of air and changing it's velocity dramatically (many blades which are fat, high pitch, and spin very fast. Like modern mini quads :) Or a jet engine... Efficient = taking a large amount of air and changing it's velocity relatively little (one long skinny slow spinning propeller) With this in mind, which do you think is more efficient at hovering? Harrier or Helicopter? This is the same reason a Piper Cherokee with it's short fat wing is much less efficient and glides like a rock compared to a glider with it's long skinny wing. (propeller are just spinning wings) However as with everything in life, there are disadvantages. Single blades are more complex to make and balance. Their center of thrust will always be unbalanced. And with full size aircraft the limiting factor is often the propeller tip speed getting too close to the speed of sound, so in order to load a large engine appropriately you must increase the width, pitch, or number of blades (since speed and length have reached their limit)

getting the right balance is a problem

EDFs suck

Samm Sheperd yes they do, they are supposed to.

Yep all awesome loud prop noise

and some more motors.. :p

I mean I would love to do that

***** It would be incredible; to do, to see... if it works out well enough i would definitely try it. Nice work btw

I'm game! (>*

Osimmac can you help me with money

I put my setup in the description! :)

Thanks :D

I'm not trying to make anything useful or better than anything else, I'm just having fun

I see, but if you had tried on a smooth road, your video would have been much more interesting ! Many viewers would have been interested in seeing the speed that can be achieved with your system. Your video don't show it

it was 35mph on the runway. This is a series of videos, more to come

Ok, hope to see more !

+The Lennipede k cool

+StealthElectronVIP that's not the point, I don't want an ebike.

Got one on the way :)

It's not about an ebike. It's about the simple idea and playing with it

wow, quite $$$$

Ya that is there biggest down side. For our battle bot though they were the only clear choice. Also take a look at the tool i made for Electric motors. www.electric-skateboard.builders/t/google-spreadsheet-for-easy-and-fast-calculations/13337

The point is just to play and have fun not to make an E-bike

***** Ahh, so why the patron then ?! For the video content ?

Yep last video was with skis and I do lots of RC/Drone stuff