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Author Topic: Ministick  (Read 737 times)
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Rossclements
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« on: December 28, 2016, 05:11:48 PM »

Due to some discussion on youtube I am posting some pictures of a self designed ministick, best time in a "dirty" 20 foot ceiling gym is 4:38, that flight was with a 2x loop of 19 thousandths. Advice and things i could change is welcome!

Thanks!
Ross

Sorry about the weird color, something is up with the camera lens.
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Ministick
Ministick
Ministick
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Hepcat
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« Reply #1 on: December 28, 2016, 07:46:44 PM »

Ross,
From the photographs and the flight time perhaps you should be offering advice not asking for it.  I thought at first that the propeller blade was too thick but a further look said that was just camera dsitortion in close up.  I don't think dihedral on the tailplane does much, except to be more difficult to build. Smiley  To be serious; trying different propellers and matching the rubber to them is what brings high performance indoors.  I know it is fiddly on a small model but if you can make a hub that will accept different blades and where the blade angle can be adjusted you will progress to higher times.
John
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dslusarc
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« Reply #2 on: December 28, 2016, 10:24:48 PM »

Not sure how much your model weighs but I fly my ministick on a 11-12" loop of .030-.032" wide rubber. I also run around 17" pitch though some run higher around 20". Rob Romash does the opposite he runs lower pitch and longer thinner loops of rubber around 14" long. So a longer loop would be my suggestion.

Don
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Rossclements
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F1D is pretty neat



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« Reply #3 on: December 28, 2016, 10:47:48 PM »

According to my scale it is .53 grams, I am not sure I believe it, it has been acting up lately. I think I am running too low of a prop pitch, I have no Idea how to calculate pitch so I used a jig from a IMS mini stick kit.

Thanks!
Ross
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dslusarc
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« Reply #4 on: December 28, 2016, 11:49:35 PM »

The weight is not too bad. Can you post a photo of the prop jig from the kit? Does it use a 45 degree angle to set the pitch? If so for a 45 degree angle
Pitch = 6.283 * Radius

so 17/6.283= 2.70" so 2.70" from the prop shaft you set the blade to 45 degrees.

Here is a simple prop jig I just did for a Nocal. This one is set to 15" pitch, just move the little triangle from 2 3/8" to 2.7" to get 17" pitch
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=21522.msg199139#msg199139
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=21522.msg199140#msg199140

Don

               
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Rossclements
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« Reply #5 on: December 29, 2016, 12:10:33 PM »

I am out right not but when I get home I will take a picture, Looking at the rules do you think a Canard would be allowed? It says it shall be a monoplane but could you make a canard? I was just thinking about this because a canards stab still produces lift. So it would Kind of be an increase in wing area.
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dslusarc
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« Reply #6 on: December 29, 2016, 01:27:45 PM »

With the aft cg on indoor models the stab already does lift.
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jakepF1D
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« Reply #7 on: December 29, 2016, 02:12:39 PM »

A canard is legal, but keep in mind the 50% stab area maximum.  I don't think it would necessarily offer any advantage over a standard layout.

At 530mg you're about 25% heavier than the minimum.  That has a big impact on flight times so I would focus on weight reduction. 

The other big place you can improve is winding.  The more turns and torque you can get into the motor, the more energy you have available.
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Rossclements
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« Reply #8 on: December 29, 2016, 04:33:29 PM »

Yeah, that is what I figured. I still might make one for fun though. I believe that the triangle is 30 degrees, I dont have a protractor. On the jig the 30 degree angle it is 1.75 inches from the shaft.


Thanks!
Ross
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Maxout
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« Reply #9 on: December 30, 2016, 07:08:34 PM »

Yeah, that is what I figured. I still might make one for fun though. I believe that the triangle is 30 degrees, I dont have a protractor. On the jig the 30 degree angle it is 1.75 inches from the shaft.

You can download an image of a protractor and print it off. Works great.

Canards are fun. Ministick rules produce a weight distribution that makes them uncompetitive, but don't let that stop you if you enjoy things that are different. Flying wings are good fun too.

Canards are extremely competitive in scale events and certain outdoor endurance events.
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Hepcat
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« Reply #10 on: December 30, 2016, 07:43:22 PM »

Ross,
If you don't have a protractor handy the attachment below, which I did for somebody a long time ago, might be of some help to you.  The bottom of the piece of cardboard can be cut to any length (and shape) that is convenient, perhaps even stuck to a piece of wood as a stand.  It all depends on how you hold the propeller for testing.
The emphasis on checking the blade angle at 3/4 the radius of the propeller is because it is that part of the propeller that does most of the work.  If the blade angle at three quarter radius is correct there is a good chance that the propeller will work well.  That is NOT the case if the blade angle check is at some other radius.
John 
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Re: Ministick
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Rossclements
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« Reply #11 on: December 31, 2016, 10:00:14 AM »

ok, I will print off a protractor and figure it out. I Think I will also re-pitch my current prop and try some .23 thousandths.

Thanks!
Ross
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