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Builds, Repairs, Show Your Machines! => Metal & Wood Construction - Erector Sets - Meccano - Wood Structures => Topic started by: ShadetreeMotorcycle on June 18, 2021, 11:54:07 pm

Title: Nitinol engine kit review
Post by: ShadetreeMotorcycle on June 18, 2021, 11:54:07 pm
I purchased this low priced German kit really just to practice my paper cardstock Model building skills, however it built into a rather delightful little engine.
  From what I understand, Nitinol belongs to a family of alloy metals called "memory metals" the basic concept is the 0.5mm (diameter) very thin drive band is quite soft at room temperature but becomes more like spring steel when heated. So the drive belt is really where this engine gets its power! The soft belt wraps around 2 pulleys and the lower pulley is partially submerged in the pot of water heated by 1 tea light candle. As the soft belt travels down to the lower pulley, the portion of the belt under water changes to its stiff property's and "wants" to be straight so it moves forward to the straight Area of belt path (back out of water) the maker of the alloy (Nickel/Titainium) can "program" the belt to reaction at a certain temperature by changing the alloy content, this kit supplied belt activation temperature is approx 120 degrees F
  As I built the model I felt sure the running would be iffy at best, to my surprise it runs very well (self starts) and makes similar power to a small Stirling engine say about like the China QX6 but peak torque at lower RPM than QX6....I am going to guess about 375 RPM is my best so far.
  The kit is constructed mostly of high grade greeting card type paper cardstock, there are 2 aluminum axles, black plastic pulleys (to run in water) and plastic bearings. The firebox and boiler kettle are made from an aluminum beverage can.

Much of the build time is to laminate 4 layers of cardstock to create "each" rigid structural part. The first photo is of a stock kit build, I took the extra step to "paint" the raw edges of the paper "plywood" with Sharpe markers in an attempt to give a more finished look.
  I believe the engine has the power to run "some" of the more basic low power consumption accessories like Wilesco type. It was designed to power a paper Ferris Wheel also offered by the manufacturer Astromedia.
  The. Very simple kit could easily be cut from wood (or your favorite material) if you find paper construction offensive, but like the Nitinol.

Stock photo:
  The stock photo shows 2 extra "rods" that do nothing but add visual motion. They can be left off to reduce drag.

[attachimg=1]

My engine running:

[attachimg=2]
Title: Re: Nitinol engine kit review
Post by: ShadetreeMotorcycle on June 19, 2021, 12:17:05 am
Beeswax tea light candle power, but any tea light size candle will do, I recommend beeswax or soy candles over paraffin as they burn much cleaner.

The "bricks" painted on the lower beer can firebox was my idea but kind of a failure, the pin-stripe tape I used to mask was terrible quality, I will repaint that!

[attachimg=1]


Maintaining 120 deg is no issue for the tiny candle, much like a steam engine I heated 5/8 cup of water in microwave for 1 minute and filled boiler kettle, the engine self started on this water before I even slide the candle under the boiler kettle! It will run approx 2 min after removing the candle as well.


[attachimg=2]


There is an engine plate to be signed and dated by the builder if desired.


[attachimg=3]
Title: Re: Nitinol engine kit review
Post by: ShadetreeMotorcycle on June 19, 2021, 12:56:00 am
Verdict: I enjoyed the kit build very much, it occurred to me as the kit is reasonable price, it could be purchased as a pattern and the model could be built from a favorite hardwood or tin plate brass/copper/Aluminum bent in a U shape would provide the main frame, there are only 2 straight axles so it's easy. The stock kit could benifit from better bushings, the plastic bushings are perhaps nearly .018 oversize, small brass tube, glass beads, or even roller bearings could be fitted if one wanted to get fancy!
  The magic is in the Nitinol power band, a spare can be ordered from Astromedia, so you could scratch build a model as well!
  I doubt this thread will get much interest,  but it IS a small engine that runs well, if 1 or two people enjoy the thread, all is well.


Here is a short YouTube video of what the engine looks like if built stock, My engine runs faster and more quietly without the 2 extra sliding rods fitted.

https://youtu.be/y16ZfzzqF6A
Title: Re: Nitinol engine kit review
Post by: Dampfopa on June 19, 2021, 02:31:03 am
Thank you for your post and the description contained therein. I liked it. AstroMedia Publishing offers many interesting models. It is worthwhile to stop by their site.
Title: Re: Nitinol engine kit review
Post by: txlabman on July 08, 2021, 08:30:24 am
What a neat kit.

I am going to order one and have a go at it.

Thanks for the review and video.
Title: Re: Nitinol engine kit review
Post by: ShadetreeMotorcycle on July 08, 2021, 03:45:46 pm
What a neat kit.

I am going to order one and have a go at it.

Thanks for the review and video.

I'm glad your going to try one! Feel free to ask questions once your kit comes in.

Update:
I had originally left off the 2 "boxer" arms from my engine, but have since added them, I did dry lubrication of the long slot and also the wood peg that rides in the slot with pencil lead, the paper and wood are easily burnished with pencil lead and really smooth the motion well. It still does slow the engine a little but mine runs more quietly than the one in the video. Also slowing the engine is not a bad thing if you plan to build the Ferris wheel later, also if you run the engine fast without the extra arms the tiny joint in the Nitinol power band has a tendency to throw a little bit of water droplets around at speed.
   Good luck with your build and feel free to post here or start a new thread!-Ben