Spinnng Props

[Boomstick]

Finally getting my 1/72nd B-36 kit off the shelf for another project for my dad. I have been searching high and low for info on some kind of motor I can use to spin the props. I'd like to be able to turn on the props via a remote control because he wants to hang it in his office. I hope I can pull this off for him. Any help is greatly appreciated.

[pgpelect]

You should look for vibration motors from old cell phones, when you remove the weight they should be ideal; small, quiet...

I don't know if that helps a bit, it is the only thing I can think though. As for the remote, it's not impossible but it's gonna be a pain you should avoid IMHO.

[blunce]

I used to have on my pc before the HD crashed, a Fine Scale Modeler article on using the cell phone or pager (remember those!?) vibration motors as mentioned by pgpelect, but it went away along with all my other stuff when the HD fried. That's what you want to use though.

[blunce]

Here's another idea from this thread:

The vibration motor extracted from a Gillette Fusion Power razor fits nicely in a Bronco 1/48 Predator. Every few months these are FREE after rebate or Sunday newspaper coupon at drugstores. Like vibrating motors from cellphones, just remove the off-centered weight eccentric (tiny metal part in photo) from the motor shaft.

With the single AAA 1.5 Volt battery in the razor, the prop spins way too fast. To your point, it seems as if something is going to fall apart. Some Tamiya motorized prop-action kits provide a diode (the tiny black part on red wire in photo) which reduces the voltage to under 1 Volt which makes the RPMs more realistic. Diodes cost about a dime.

There's a basic motorization aftermarket kit from Doyusha for about $10 with motor, switch, battery connection, and wiring. It appears that motor would fit your MQ-1.

[Boomstick]

Outstanding. Thanks for the help.

[riceballtrp]

If he just wants the effect of the spinning props, I suggest going to propblur.com and check out their line of "spinning props." I just bought some and they are impressive!

[Uncle Uncool]

Boomer!

Howdy, lad? Three months ago I got an assortment of tiny DC motors from this company here. Not only are they awesome, but also there is quite a large range of options with regard to the motor's body diameter 'n' lenght; shaft diameter 'n' lenght; connector type, rated voltage, torque 'n' speed.

Nay able to help ya out with the remote controlled motors, sorry. I don't think they'd ever exist in a small size of motors, tho.

Cheers, fella!

Unc²

[The Loggie]

A Remote Control, er. If you have one power-source for all 6 tiny motors, then all you need, is an RC to close the circuit. A garage-door opnener could do the job. I suggest that you ask at your local electronics shop (Jaycar, Dick Smith, Radio Shack etc).

Good luck. George, out....................

[stan2004]

The big auction site has pager motors for about $1 a piece. Some come without the weight. Otherwise search the web for how to remove the eccentric (weight) from a pager motor and you will see many how-to articles. Readily available motors in hobbyist quantities will come in metric diameters like 4mm, 5mm, 6mm, etc. So study your nacelle. The shafts are also metric and for the size motor you need it will probably be between 0.6mm to 1.0mm. Experiment drilling into some scrap sprue to determine if a non-metric or numbered drill bit will give you a nice press-fit to the prop. I cannot over-emphasize the need to drill a concentric/centered hole to minimize prop wobble. There is some info on the web on techniques but there are so many prop styles that it's hard to generalize. I do not recommend placing a larger motor further back where there might be more space and trying to run a shaft extension to the prop. This will multiply prop wobble.

Virtually every motorized kit I've seen spins the prop way too fast. This is because the simplest circuit of just a battery connected to a motor does not provide any speed control. It takes more voltage to start a motor than to spin it. Obviously most modelers just live with it as the options get complicated and expensive - geared motors, electronic control, etc.

Note that a remote control receiver needs power. So for the >99% of the time that the plane is just hanging it is draining the battery 24/7. Considering you will hang the plane with wires, you might consider if there's some way to run power (but not 120V AC!) through the support wires. If nothing else this may allow a larger battery pack in the ceiling that would require only changing batteries once per year or whatever. I realize the limitations of running or disguising wires to the ceiling in an office environment but if you can swing it I think that's the way to go. That way you can use a low cost remote control. For example I got a wireless remote control holiday light system from Home Depot for about $10. It switches 120V AC to a remote outlet so you could switch on/off a low-cost DC wall transformer or cellphone charger and run the low-voltage up to the ceiling and down the support wires. The remote is very small with just an on/off button.

If you go the battery-only route, look at an RC car - some starting at under $10 including the remote. Strip out the electronics from the receiver and connect the motors to where the receiver drives its motor. It takes very little power to drive your spinning prop relative to the RC car transmission so a single receiver can drive multiple motors. Further discussion can help select parallel or series wiring and other such details. The remotes for these can be bulky for simple on/off control providing useless functions such as reversing the car which would spin the props backwards.

[balls47]

Ditto on PropBlurs. They have everything you need and the customer service/support is second to none. I do mostly jets, and 99% of my models are in-flight displays. When I do a "prop-job," I can't see me ever doing anything else but PropBlurs. Again, you can't beat the product or the customer service. Dave is great at what he does!

[B-17 guy]

If someone has mentioned this, I missed it but.....If you were to go through all this, get it all engined up, props spin and all and run the props while the model is hanging from the ceiling. Wouldnt the model around? I'm guessing here but I could see the model moving around possibly causing damage.

[PetarB]

And that is bad... how? :P

[Fly-n-hi]

If someone has mentioned this, I missed it but.....If you were to go through all this, get it all engined up, props spin and all and run the props while the model is hanging from the ceiling. Wouldnt the model around? I'm guessing here but I could see the model moving around possibly causing damage.

It wouldn't be a problem if you flattened out the props so that they aren't cambered and have zero angle of attack.

[signals]

I've been planning on doing this...all these are good ideas

[stan2004]

Re unwanted motion, no problem if OP supports model from multiple attachment points. A 1/72 scale model spinning at takeoff RPM and blade pitch will not even taxi much less lift unless the ambient air density is also scaled down. One of Tamiya’s 1/48 motorized series taxi’d under its own untethered battery power. To do so, the prop spun unrealistically fast and other considerations were required.

If you are truly intent on motorizing with remote control come hail or high water, it can be done. Some liberties may be required. For example, since the plane hangs above eye level hide a thin solar panel on an upper wing surface to power the RC receiver as you’d only operate this when office lights are on. You’d still need batteries to supply motor power but eliminating the constant drain of the RC receiver does wonders to battery life. For a few dollars in parts you can assemble a circuit that kick-starts the motor voltage to get it going then lowers it to run at realistic speeds. In a noisy office environment where you can’t hear the motors, prop blades spinning over, say, 1000 RPM can appear invisible. And slower prop speeds mean less power and longer battery life.

It comes down to how determined you are to motorize vs. something like prop blur vs. nothing at all.

[Diamondback Six]

Interesting thoughts... I've been thinking about adding lights and motorization to the CH-53E I'm working on.