Re: Re: Optimizing a ministick

From: matthew taudevin <mattnsim_at_yahoo.com.au>
Date: Fri, 19 Dec 2008 20:28:11 -0800 (PST)

thanks bruce for the info.

My props have helical twist.

rubber is 11" loop of 1mm square and weighs .5grams

The model weighs .6grams without rubber so all up weight with existing motor is 1.1grams. A little heavy but it is my first ministick. i may be able to take some weight off with some light sanding of the fuselage.

ceiling is normal pointed variety and is about 20 feet high. here is video you will see the obstructions that I mean.
http://www.youtube.com/watch?v=-wzy7v0funk

I have calipers and a home made balance beam made for me by my engineer freind craig.

I do not have a torque meter

I just sat down with the model and put it in it's cradle and just watched it. The blades do move a little but i noticed that one of the blades always pointed to the floor more than the other.... OOPS. Sanded that one back and the prop is balanced. When you say the prop has to turn when it is in it's cradle do you mean that it moves around or spins like a prop should? Mine just moves around in my room with all the windows closed. It does not turn completely around. I will post some pics of the model on the Yahoo forum so that you can see first hand what it is like.

thanks for the help fella's

regards
Matthew


 



________________________________
From: Bruce McCrory <hbm55_at_comcast.net>
To: Indoor_Construction_at_yahoogroups.com
Sent: Saturday, 20 December, 2008 1:02:56 PM
Subject: [Indoor_Construction] Re: Optimizing a ministick

Unfortunately, we always need to know everything. Ceiling with no
obstructions; weight of model, rubber section, length, rubber weight,
turns, torque, number of turns left after landing, height, weight,
social security number, bank account number, etc.; put a "?"
preceding every comma. The usual stuff....

Then, we (you) start dialing in the outrageously giddy flight times,
ie., the fun stuff - for everyone.

Ministicks do very well in any height room when there are no ceiling
obstructions or things to snag the model. They were called parlor
sticks, for flying in kitchens and living rooms.

My guess is you may not have super fancy weighing scales - for indoor
duration, something reading 0.01g is good. Or, a torque meter; or
calipers. There are wire spring scales (designs on web), balance
beams (again, designs on web, you have a new dollar bill, .98 grams);
and torque meter designs (with thought and wire one could be made
from a ball-point pen.) And, finally, stick calipers can be gotten at
many hardware stores for really cheap. Indoor modeling is for poor
people - which most of us are, now.

Aach, just checked. Files don't have much.

Is your prop flat, or have hellical twist? If built on a standard
form, the 50% of radius mark is a 45-degree angle. Get both blades to
the same angle.

Here's some targets for a model at its design weight, .43 grams. 11-
inch, .023-inch x .042" section, about .4 grams of Tan II rubber. A
perfect flight will have very little launch heebie-jeebies and look
like a butterfly poking around in the ceiling for 10 to 11 minutes.
The rest of the flight "separates the men from the boys" as Andrew
Tagliafico likes to say.

Before you do any flying, make sure the prop shaft spins without any
friction. If the model sits in the stooge and the prop just sits
there too, there is friction. The little bugger has to be a pain in
the !_at_!#~ and want to turn. Even when you can't feel a zephar. This
is the key to long flights. Don't fly until the prop turns by itself.

Grab a sheet of paper. Write down everything from the above list of
critical questions. Send the personal data to me. =) Before you wind
and fly, take a section of the rubber you will use - about 2", 3"
loop and wind it to break. Count the turns. Try it again; average the
break count and call it 100% breaking turns. Wind the real motor to
90% of the breaking turns - per inch!

Come back to the farm with the data and 90% of the guys wanting
competition will reveal more secrets.

Bruce
In Seattle




--- In Indoor_Construction_at_yahoogroups.com, "mattnsim" <mattnsim_at_...>
wrote:
>
> Hi guys, I have not posted very much on this group but I need to
ask
> the experts. I have a ministick that Can do about 2:45 in a gym
that
> has a ceiling of about 20feet.
>
> When the plane lands it always takes about another 2 minutes for
all
> the turns to unwind. Me thinks that I should shorten the length of
the
> rubber loop? I am sure that it is a 13".
>
> The pitch on my blades also may be a little steep. What do most
people
> angle there blades at on mini sticks? Sorry I am not really an
expert
> with the trerminology.
>
> regards
> Matthew
>



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Received on Fri Dec 19 2008 - 20:28:18 CET