Design

[Less_Incidence]

And time is exactly what I don't have much of at the moment. My regional is in about 3 weeks and I and my jazz group are recording our album in two weeks, plus I have classes blah blah blah...

Enough with my problems. Anyone have advice on trimming/sanding the flaring Ikara props to make them most effective?

[Chris_L]

I am trying to trim the ikara flaring propellers with some luck but i kinda wanted a guideline as to where to start. I have basically just sanded it much thinner, and also clipped off good chunks of the shorter side of the prop.

[nxtscholar]

It's been mentioned many times before that Chris Goins' Double Trouble design featured a good guideline on sanding a flaring prop down to even better performance levels: http://www.indoorduration.com/ftp/DoubleTroubleSO.pdf

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[jander14indoor]

Before you spend the time sanding, consider, the rules this year allow you to make your own props. You might be better taking that approach. Might.

Jeff Anderson
Livonia, MI

[DoctaDave]

Would there be any large enough advantage of making your own props that it would outweigh the time it takes to practice and learn to make them?

[jander14indoor]

Hard to say. It's not that hard to learn to make your own very good props. People tend to think of them as difficult, but turns out they aren't very hard at all.

First big advantage is its very easy to make a good light one less than a gram. More weight to build into stiffer structure, not a bad thing. Anyone can take advantage of this with little effort.
Second advantage is ability to modify/tailor to need. Admittedly this one is harder to realize, but it is a real advantage.

Simplest approach is bucket formed blades. No special forms, only took me a couple of tries to get good ones and actual time spent wasn't much.
More difficult is true helical pitch because you have to make a form. But once made, props don't take long.
For SO, blades will be solid, but thin balsa.

Regards,

Jeff Anderson
Livonia, MI

[nxtscholar]

One source I found helpful, especially when attempting bucket props, was INAV's issue on propellers: https://indoornewsandviews.files.wordpr ... _press.pdf

Do note that some things in the issue are not worth reading for SO (i.e. rules say no VP props)

[jander14indoor]

INAV is good for all things relating to indoor rubber powered free flight. A little more hard core than SO, this newsletter is aimed at folks who build 0.5 to 1.2 gm airplanes and think a 3 gm penny plane is a heavy class. But it has good ideas how to control weight, make fragile things from balsa, etc. Pick and choose and it will definitely improve your flight times!

Jeff Anderson
Livonia, MI

[bjt4888]

nxtscholar,
You did an excellent job researching the web to find this INAV issue. I has good info on bucket props.

Jeff,
Would it be within the scope of this wiki for me to post a sample simplified solution to the bucket prop development problem using the Fred Rasch spreadsheet and a couple of pictures? If not, I understand.

Thanks,
Brian T.

[jander14indoor]

What, do I look like a copyrite lawyer or net nanny?

The subject would certainly be within the scope of the forum.

I'd think fair use and proper attribution would cover what you propose from an ethics point of view. Especially as it sounds like you aren't copying directly, but abstracting.

I think Fred is still around if you wish to ask his permission, and INAV is alive if you wish to ask theirs.

Jeff Anderson
Livonia, MI