Anybody else scratch building tonight?

[mastermalpass]

A couple weeks ago, I got ducts and internal fairings set up on the engine for the new ship concept. The beams for the motor mounts were cut 6mm wide, allowing for the internal fairings to be simple strips of foam sanded to shape and epoxied straight onto the wood. I cut a groove out of a couple on each so I could lay the motor wires into the fairings. Tape was then wrapped around to give them a nice sturdy finish.

The piece is feeling nice and solid! Since then it’s all been solder and heat shrink. First just putting the basic connectors on the motor wires and ESCs then today (after ordering solder, shrink tubing, wire and XT60s - all of which I ran out of) I finished the ESCs and started on the Y-links for the battery.

After testing the motors individually and finding that on 3S, one prop can easily start lifting the whole module up at just 20% throttle, I mounted the ESCs up above the air intake (I figured that’s the best way to cool them without causing much turbulence in the ducts) and began work on the Y-link for the battery.

 

[tomlogan1]

The Typhoon is ready for her maiden 😍
last year I built the black jack and this year it’s Moggy
running 90mm wemotec mini fan and HET typhoon motor on 6s
View attachment 244133

Magnificent! I'd be afraid to fly something that beautiful.

 

[shadeyB]

A couple weeks ago, I got ducts and internal fairings set up on the engine for the new ship concept. The beams for the motor mounts were cut 6mm wide, allowing for the internal fairings to be simple strips of foam sanded to shape and epoxied straight onto the wood. I cut a groove out of a couple on each so I could lay the motor wires into the fairings. Tape was then wrapped around to give them a nice sturdy finish.

View attachment 244157
View attachment 244158

The piece is feeling nice and solid! Since then it’s all been solder and heat shrink. First just putting the basic connectors on the motor wires and ESCs then today (after ordering solder, shrink tubing, wire and XT60s - all of which I ran out of) I finished the ESCs and started on the Y-links for the battery.

View attachment 244159

After testing the motors individually and finding that on 3S, one prop can easily start lifting the whole module up at just 20% throttle, I mounted the ESCs up above the air intake (I figured that’s the best way to cool them without causing much turbulence in the ducts) and began work on the Y-link for the battery.

Looking good buddy, have yet to try the BDF set up, looking forward to see the results and finished product 🙌

 

[shadeyB]

Magnificent! I'd be afraid to fly something that beautiful.

Thanks buddy
im feeing the same but there’s nothing more I can do than punch the throttle and jam those sticks 😂😍👍😜

 

[mastermalpass]

Y-Links complete. I also mixed in differential thrust on the pitch axis as that is how this craft is going to control its pitch. Then I hastily threw together a test stand.

On 4S, the two 5x4.5 3-blade props produce 1100g of static thrust at full throttle. The overall set up of this engine is 262g, 542g if I include the 1500mAh 4S battery. So I have 648g of space before the thrust to weight is 1:1. Hopefully the ducts I make will not only add little weight, but also cause a minimal loss of static thrust as well. Only way to find out is to build said ducts and see how it goes, so that’s the next step.

Though I am wondering if I wouldn’t be asking too much of the 20A ESCs if I used 4-blade bullnose props instead. These ESCs are fairly big for 20Ampers and being BLHeli brand, I’m thinking they are designed to handle pretty heavy loads. Anyone have any thoughts there?

 

[mastermalpass]

Looking good buddy, have yet to try the BDF set up, looking forward to see the results and finished product 🙌

Cheers! It’s designed to go in a VTOL spaceship-looking drone, but if my concept turns out to be unviable, I’ll be sticking this engine inside a plane, as I’m quite proud of how the piece itself has turned out. 😁

 

[Crash Test RC]

Repaired this aircraft after a crash. Will be fiberglassed and put up in FF combat.

 

[skymaster]

A couple weeks ago, I got ducts and internal fairings set up on the engine for the new ship concept. The beams for the motor mounts were cut 6mm wide, allowing for the internal fairings to be simple strips of foam sanded to shape and epoxied straight onto the wood. I cut a groove out of a couple on each so I could lay the motor wires into the fairings. Tape was then wrapped around to give them a nice sturdy finish.

View attachment 244157
View attachment 244158

The piece is feeling nice and solid! Since then it’s all been solder and heat shrink. First just putting the basic connectors on the motor wires and ESCs then today (after ordering solder, shrink tubing, wire and XT60s - all of which I ran out of) I finished the ESCs and started on the Y-links for the battery.

View attachment 244159

After testing the motors individually and finding that on 3S, one prop can easily start lifting the whole module up at just 20% throttle, I mounted the ESCs up above the air intake (I figured that’s the best way to cool them without causing much turbulence in the ducts) and began work on the Y-link for the battery.

so how big is this thing going to be any idea?

 

[mastermalpass]

so how big is this thing going to be any idea?

The engine itself is 29cm long and I’m thinking the ducts will reach out about 20-25cm either side, for a 69-74cm length overall. Then if that’s not too heavy, I’ll build up the outside shell to give the craft an overall length of 1 metre.

 

[L Edge]

An experimental VTOL system to go inside sci-fi spaceship models. I want to make a model Taiidan Assault Frigate from the game Homeworld - notice how it’s fatter in the middle and narrower at the front and rear:

View attachment 243962

I want to see if wider props in the middle of a ship can be ducted to narrower (longer but with the same surface area) nozzles via S-bends. The nozzles will then vector the thrust in the same way a bicopter vectors its props.

Once I have this ‘power core’ completed, I will measure the thrust without the ducts. Then I will add ducts and measure the thrust again to see how much thrust is lost in the ducting. Hopefully, not much thrust is lost coming through ducts that go from a circular cross section to a rectangular one, as rectangular nozzles will be much simpler to vector.

Are you going to do a thread on this? Very interested in the circ to rectangular exit and how it exits to surrounding air. It is really different design and exploring the unknown.

 

[Piotrsko]

I would be interested to see if squaring off the prop tips tight against insides actually improves efficiency like Nasa promised.

 

[mastermalpass]

Are you going to do a thread on this? Very interested in the circ to rectangular exit and how it exits to surrounding air. It is really different design and exploring the unknown.

I think I might, now you mention it. Exploring the unknown is pretty much the entire purpose of building this prototype. 🙂

 

[FlyerInStyle]

Repaired this aircraft after a crash. Will be fiberglassed and put up in FF combat.

be careful with fibergalssing I have already made a couple planes too heavy from excess use of epoxy, etc. fibergass can be quite heavy especially if the plane is overweight as is.

 

[mastermalpass]

I would be interested to see if squaring off the prop tips tight against insides actually improves efficiency like Nasa promised.

If big blunt blade tips are within micrometers of a duct wall, the vortexes are blocked from spiralling off of the blade tips, making the system quieter and more efficient. However, engineering that level of precision in foam is not something I can see myself achieving, at least not without adding a bunch of stuff to help hold the form of the duct - which may end up being enough weight to cancel out the efficiency gains.

One of the things I’m hoping to prove with this prototype, is that it works with a rough form. A core preference of all my designs is that they can be made entirely with hand-held tools and shrug off the imperfections. A pet peeve of mine is when you’re watching a “building a homemade X” on YouTube and half way through the process they start carving chunks of metal on a giant lathe as if we all have one of those laying around. 😂 Not that I wouldn’t love to see someone pick up this concept and optimise it by 3D printing the most efficient system ever, allowing for some really elaborate spaceships to grace the skies.

 

[L Edge]

I think I might, now you mention it. Exploring the unknown is pretty much the entire purpose of building this prototype. 🙂

Hope you do.

 

[hankflies03]

Here is a short video of the multiplex funnycub that I made out of foamboard. It flew ok but it still needs some improvements.

 

[L Edge]

I would be interested to see if squaring off the prop tips tight against insides actually improves efficiency like Nasa promised.

Funny story, it does. My cheap 5 bladed has a clearance that a truck could drive thru between blades and wall. (Did you know having 5 blades, when inside chamber is pressurized, it leaks forward between blades as well as it bleeds out while it rotates..
So to reduce wall leakage and increase thrust(statically) I wound 2 layers of Scotch magic tape to the housing and reduced the gap.
Proof was hover plane in cellar without tape(throttle was 51%) and then recharged battery to 1/100 volt with tape wound around the housing and to hover, it was throttle 46%, so I gained static thrust.

Another experiment I did(worked to some degree) was I built a thruster system(think Apollo) were I had carbon hollow tubing pick up airflow behind the blades and transfer to each wing coming out perpendicular) to counteract torque of EDF when vertical so single engine plane doesn't rotate due to lack of airflow across wing when stationary. (Have video if you want to see what it did to prove it). By the way, did pitot tube study to show increase in thrust .

 

[mastermalpass]

Funny story, it does. My cheap 5 bladed has a clearance that a truck could drive thru between blades and wall. (Did you know having 5 blades, when inside chamber is pressurized, it leaks forward between blades as well as it bleeds out while it rotates..
So to reduce wall leakage and increase thrust(statically) I wound 2 layers of Scotch magic tape to the housing and reduced the gap.
Proof was hover plane in cellar without tape(throttle was 51%) and then recharged battery to 1/100 volt with tape wound around the housing and to hover, it was throttle 46%, so I gained static thrust.

Another experiment I did(worked to some degree) was I built a thruster system(think Apollo) were I had carbon hollow tubing pick up airflow behind the blades and transfer to each wing coming out perpendicular) to counteract torque of EDF when vertical so single engine plane doesn't rotate due to lack of airflow across wing when stationary. (Have video if you want to see what it did to prove it). By the way, did pitot tube study to show increase in thrust .

Scotch Magic tape eh? I might have to give that a go. Found myself a set of 5-bladed Bullnose props as well.

 

[bisco]

Here is a short video of the multiplex funnycub that I made out of foamboard. It flew ok but it still needs some improvements.

well done hank, that was excellent!

 

[Piotrsko]

Might need to sand the tips to fit the tube better. Picture suggests they aren't square. Scotch tape is pretty consistent for use as a shim. 3m electrical isn't.

Hmmm: Some do, some don't have better thrust. Tis what I discovered, even in the nasa data. Rings do act as muffler however.