Jeff
I agree that bucket props might be better as a pattern for a lighter balsa prop than as the final one to use. The nicest part about the bucket ones is the quick build in a variety of sizes, so you can get a good balance between the rubber and the prop.
I have an Ikara 225 mm prop that I tried under the same test as my somewhat larger one with bucket blades, The Ikara one weighs 2.2 grams with a Delta Dart hanger and 1/32 inch wire hook. I got 135 seconds total run out of a 10 inch loop of 1/8 rubber at about 825 turns, This averages 360 rpm. The trick to using it would be to get more turns in a narrower rubber motor of the same weight, without losing altitude at cruise.
I have used the smaller diameter (5.25 inch, 133 mm), heavy (2.8 gram), plastic prop from a Delta Dart outdoors in the original application as well as indoors on a Markos' Double Whammy. With 1/8 inch rubber outdoors, the Dart will stand up to a bit of wind. A 10 inch loop takes only 40 seconds to unwind from 800 turns with that prop. I get double that time with nearly the same weight of rubber and the same prop by going to a 14 inch loop of 0.080 inch rubber and 1500 turns for the Double Whammy indoors.
Hitting that sweet spot where the plane cruises without dropping takes a lot of testing. The more props the better.
Received on Thu Nov 20 2014 - 15:24:39 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:48 CET