Help! Smoke Generator(Powder) for RC electric planes

[cdfigueredo]

¡Hola a todos!
Hace un tiempo vi por casualidad este vídeo en internet y me llamó la atención porque llevaba mucho tiempo buscando hacer algo similar.

El prototipo de vídeo funciona bastante bien pero tiene mucho margen de mejora.

• La salida de polvo no está controlada por radio
• La entrada de aire no es muy buena.
• El polvo tiende a depositarse dentro del recipiente, lo que significa que no siempre se mezcla con el aire entrante.
• La forma del dispensador no es aerodinámica y por tanto produce una resistencia no deseada.

Teniendo en cuenta los puntos anteriores quise crear un prototipo más sólido que permita:

• Se puede adaptar fácilmente a casi cualquier tipo de avión.
• Fácil de llenar el tanque
• Controlar la cantidad de polvo que se libera
• Y haz que se vea súper genial.:Frío:

Estoy abierto a sugerencias y ayuda, creo que puede tener futuro. Si tiene alguna idea, compártala para mejorar este proyecto juntos.

Actualizado
Los chicos de Flite test probaron la versión original aquí

 

[cdfigueredo]

For the time being I have created this prototype very quickly to test the theory.


It's an old medicine bottle with a hole in the front and a hole in the back. The screw-on lid helps to easily fill the bottle. The servo moves a plastic piece that has a funnel attached to it to allow air to enter through the hole. I really chose the first bottle I found, the square shape caught my attention, but the weight is quite heavy, about 20 grams without adding the powder.

 

[cdfigueredo]

I've been working on a model to 3D print, but I think I'll wait to play with the prototype a bit.

 

[NM156]

Awesome work on the modeling!

 

[Mutley]

For the time being I have created this prototype very quickly to test the theory.
View attachment 219377 View attachment 219378 View attachment 219379

It's an old medicine bottle with a hole in the front and a hole in the back. The screw-on lid helps to easily fill the bottle. The servo moves a plastic piece that has a funnel attached to it to allow air to enter through the hole. I really chose the first bottle I found, the square shape caught my attention, but the weight is quite heavy, about 20 grams without adding the powder.

Is that a TBD devastator in the background?

 

[cdfigueredo]

Is that a TBD devastator in the background?

No, is a SBD dauntless. Still in progress

 

[cdfigueredo]

Well, i tested the prototype today, there is a lot of room for improvement, but I will only say that it works.
Will be sharing videos later.

 

[NM156]

What type of powder are you using? Talcum, corn starch?

Just a thought...

Use multiple holes in a circular pattern on the inlet. It should help disperse air throughout the powder chamber while retaining a single outlet.
Actuation could still be linear, but the red "gate" would port/unport all of the inlet holes.

Alternately the the gate could be circular and radially actuated with the pivot point in the center.
Super fancy could be some sort of iris.

 

[cdfigueredo]

What type of powder are you using? Talcum, corn starch?

Just a thought...

Use multiple holes in a circular pattern on the inlet. It should help disperse air throughout the powder chamber while retaining a single outlet.
Actuation could still be linear, but the red "gate" would port/unport all of the inlet holes.

Alternately the the gate could be circular and radially actuated with the pivot point in the center.
Super fancy could be some sort of iris.

Hey, I love your approach! I think it could work perfectly circular pattern holes.

 

[cdfigueredo]

Here are some pictures of yesterday's test. It's not worth uploading a video because the smoke emissions were sporadic and the day was cloudy which didn't help to see the smoke.

During the flight the powder did not come out because the airflow was generated at the top of the container while the powder was at the bottom. Smoke only came out when it made a roll or flew inverted. Also the powder I used was a little wet and had stones that could have blocked the outlet. During the moments I got smoke, it looked great and proved that it can be viable, it just needs adjustments.

After testing the prototype I think I have some ideas for improvement.

• Increase the incoming air flow by making the intake cone wide
• Move the air inlet point toward the center
• Add flow disturbers so that the inrushing air swirls in and mixes better with the talc.
• Think of a mechanism to block the container outlet, preferably driven by the same servo that opens the inlet, because powder tends to escape even when the air inlet is closed. That happend to me during the takeoff in the second flight.
  

 

[Piotrsko]

Some shaking/stirring of the powder would help flow as would generate a swirl in the container by pointing the inlet funnel at the bottom. The walls don't have to all that thick, cornstarch is lighter than talc.

 

[cdfigueredo]

I have been working on a prototype for 3D printing with many of these problems solved. The only drawback is that I don't have a 3D printer. hahaha.


So far it will be separated in 3 pieces, blue and yellow will contain the mechanism and the purple one will contain the powder.


The blue onw will works as the inlet and the yellow one will allows the valve to control the incoming air flow


A servo will controll the valve


And the magic will happend once the air pass this piece, i modeled this kind of bolt that will cause the air to swirl as it exits the yellow piece.
what do u think Piotrsko?

 

[cdfigueredo]

Adding the pilon and the servo

The biggest challenge I am facing is how to prevent the dust from escaping through the outlet due to gravity.

 

[Baron VonHelton]

....................Some shaking/stirring of the powder would help........

 

[BlockerAviation]

That's awesome! I saw something like this back when e fest was a thing. The had 2 yaks with wingtip smoke flying formation and since then I've wanted to do that.

 

[BlockerAviation]

I just need to figure out how to lighten your design a bit and somehow also lengthen the time smoke is on for my profiles

 

[cdfigueredo]

I just need to figure out how to lighten your design a bit and somehow also lengthen the time smoke is on for my profiles View attachment 219688

The 3D printable prototype is ready. To increase the smoke time i guess u will need to add more powder but that means also more weight. I was thinking on use balsa dust from sanding to fuel it, that whould be light as hell

 

[BlockerAviation]

The 3D printable prototype is ready. To increase the smoke time i guess u will need to add more powder but that means also more weight. I was thinking on use balsa dust from sanding to fuel it, that whould be light as hell

Yeah although not the easiest to get a bunch of. The one I saw at efest used baby power and it made a very nice cloud. Let me try to find the video of it.

 

[cdfigueredo]

The first 3D printable prototype is ready (DON'T PRINT, OUTDATED)
New version here: https://forum.flitetest.com/index.p...r-rc-electric-planes.69530/page-4#post-710060

There are only 4 parts that should be able to be printed without support, except for the air inlet regulating valve. The pwder compartment is glued for now, so I added a small funnel to print that will serve to fill the compartment through the smoke outlet hole.

Assembly instructions
Print and glue the two pieces that make up the pylon. You can rest them on a flat surface using the base of the pylon as a guide to achieve a perfect fit.

Screw the servo to the base and pass the cable through the hole in the base. Note that you will need to rod the pylon to screw in the servo mounting screws.

Print the valve and add a control rod preferably flexible and pass it through the hole shown in the photo. You may have to expand the hole. Put the valve between the notches but do not glue it, it should move freely.

With the valve in place, finish fitting the control rod to the servo.

If everything is correct, you can finish gluing the front part, add glue only on the outer ring. If you add glue to the center ring, you may run the risk of gluing the valve.

To install it on the model you can glue a plywood sheet on the belly and open some holes in the base of the pylon to fix it with screws. Once everything is installed on the model connect the servo to a channel of your radio that you can operate with a knob, this way you can regulate how much air you want to enter the system. To fill the powder compartment use the funnel. Do not try to fill it all, remember it is a prototype.

I don't have access to a 3D printer at the moment, so if you have one at home and time to experiment, I would love to know that you were able to test my prototype and give me some feedback. I have a lot of improvements in my mind but I need a starting point.
Thanks in advance.

STL files

 

[BlockerAviation]

Looks like there's a bit of waisted space where the front piece and the next piece back are. You could try integrating the holder for the valve on the front most section to get rid of the dead space if you're worried about that