Big electric variable pitch prop.
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Author:  Only Fine Helis [ Fri Aug 21, 2015 9:58 am ]
Post subject:  Re: Big electric variable pitch prop.


Hobby stuff pales in comparison to the fun with little ones.

It gets REALLY cool when the little ones like the hobby too. :-)

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Author:  exfokkerflyer [ Fri Aug 21, 2015 4:00 pm ]
Post subject:  Re: Big electric variable pitch prop.

Congratulations! She's a little beauty!

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Author:  tpalshadow [ Mon Aug 24, 2015 1:33 pm ]
Post subject:  Re: Big electric variable pitch prop.


Author:  Cat1 [ Wed Aug 26, 2015 11:33 pm ]
Post subject:  Re: Big electric variable pitch prop.

Hey Gentlemen!

While my life has been busy with filling baby bottles and removing filled diapers I did sneek a little shop time in to try and make a few improvements to the VPP. The blade replacement issue bothered me as it was a big deal to change blades as they were "glued" into the hubs.. I am using blades from Vario-prop which have a nice mounting boss at the root and i was able to come up with a "split hub" (very similar to a full size prop) that allows for quick changes of blades. I also took the opportunity to re-engineer the blade hubs to get rid of some of the weight..I managed to get the 40g hub down to 25g by replacing some steel with 7075 aluminum and adding the new split hub which also allows for cleaning and changing bearings without struggle. The weight reduction might not sound like much but try doing force calculations on small masses turning very fast.. going from 40g to 25g in my case removes about 250 lb of force from the thrust bearings in the hub. One would not believe the forces involved when 2 ounce blade assemblies are spun up to 12000 rpm (600-800 lbs). :shock:

hope to get it all back together soon to continue testing.....

P.S. Charlotte is a week old already.. man they grow up quick!!! :lol:

Author:  Cat1 [ Sun Aug 30, 2015 11:42 am ]
Post subject:  Re: Big electric variable pitch prop.

We are back in the air Gentlemen!! Mods seem to work very well and 4 great flights last night..

I took the opportunity to switch to a slightly smaller blade.. now using the 11" varioprop speed blades giving me an overall diameter of 12 1/4 inches.. one inch smaller than the previous flights... this allowed me to go to full forward pitch on the hub and keep the amp draw at 75 at 10000 rpm.

one thing I have noticed is how long the plane seems to fly on a smallish 2600mah pack... I am getting over 6 min flights using only about 1400-1500ma.. not sure if its a function of the prop (which has a very low -low pitch draw) or the fact that I am more conscious of throttle management because of the added control.

One thing I did play with lots last night is the downline speed control ability... If this was allowed in pattern or imac it would really allow for some awesome speed control... There is a loop on the video where the backside is slower than the upside.. not a great loop but shows the capability..
Hammerheads take some thinking as if you come off the pitch/power too fast you end up tail sliding...

When time allows I would love to put this into a more aerobatic bird and really test out the capabilities for this purpose.



Author:  tpalshadow [ Tue Sep 15, 2015 7:18 am ]
Post subject:  Re: Big electric variable pitch prop.

Congrats on the little one! Amazing work on the VPP as well.

Author:  Cat1 [ Tue Sep 15, 2015 11:32 am ]
Post subject:  Re: Big electric variable pitch prop.

Thank you so much... She is 4 weeks old today and its amazing how much and how fast they change... Took 2 months off work to "welcome" this little one and I am so glad I did... Planed to get a little more "shop time" but baby is keeping dad and mom busy "and a bit tired" so the shop stuff will wait...

There is a lot of interest on the "RC Canada" forum from my Canadian buddies in regards to having this available for scale applications.. To this end I have been working on drawings and calculations for a three bladed design in both smaller and bigger sizes

Will keep posting any progress....

Author:  Borneoben [ Tue Sep 15, 2015 11:38 am ]
Post subject:  Re: Big electric variable pitch prop.

Be sure to share the three blade variations with us here too

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