Wright Stuff C

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klastyioer
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Re: Wright Stuff C

Postby klastyioer » February 7th, 2019, 6:21 am

jander14indoor wrote:Suggestion, if you are making significant mods to Ikara props, but struggling with weight, it may be time to think about making your own props from balsa blades. You can tailor the properties and achieve significant weight reductions, 1 gram props are very doable.

Jeff Anderson
Livonia, MI


how do you know which prop block to use?
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Re: Wright Stuff C

Postby sciolywin » February 8th, 2019, 6:18 am

I recently have finished building my plane and decreased the weight by half, and I have also adjusted the angle of attacks as well, but my plane keeps stalling and is not catching enough lift for it to fly in the air. Is there anything I can do to increase the life and thrust so that it can fly for longer periods of time? Additionally, it is very unstable when it is flying, and I am worried that I have done something wrong in my build. Can someone help me?

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Re: Wright Stuff C

Postby klastyioer » February 8th, 2019, 7:27 am

sciolywin wrote:I recently have finished building my plane and decreased the weight by half, and I have also adjusted the angle of attacks as well, but my plane keeps stalling and is not catching enough lift for it to fly in the air. Is there anything I can do to increase the life and thrust so that it can fly for longer periods of time? Additionally, it is very unstable when it is flying, and I am worried that I have done something wrong in my build. Can someone help me?

could you send me a vid of the plane flying and any rubber, prop, post details?
honestly, it's not about the medals. go out there and have fun. make progress, learn a few things, have one heck of a time, because that's all that matters.
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Re: Wright Stuff C

Postby CrayolaCrayon » February 8th, 2019, 7:47 am

sciolywin wrote:I recently have finished building my plane and decreased the weight by half, and I have also adjusted the angle of attacks as well, but my plane keeps stalling and is not catching enough lift for it to fly in the air. Is there anything I can do to increase the life and thrust so that it can fly for longer periods of time? Additionally, it is very unstable when it is flying, and I am worried that I have done something wrong in my build. Can someone help me?


What current rubber are you using?

You can increase lift through the increase of wing incidence, or you can adjust the elevator downwards to also give an upward climb.
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Re: Wright Stuff C

Postby jander14indoor » February 8th, 2019, 8:06 am

[quote="klastyioer"}how do you know which prop block to use?[/quote]

Couple of choices.
You CAN make a variable pitch prop block, complicated, but doable.
What I do is make a couple varying over the range of interest, they don't take long. Indoor planes typically use P/D ratios in the 1.4 to 1.6 range. Make up a bunch of blades, select the P/D closest to the prop you are trying and just use it. Minor variations from ideal aren't real critical.

Jeff Anderson
Livonia, MI

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Re: Wright Stuff C

Postby klastyioer » February 8th, 2019, 10:57 am

jander14indoor wrote:[quote="klastyioer"}how do you know which prop block to use?


Couple of choices.
You CAN make a variable pitch prop block, complicated, but doable.
What I do is make a couple varying over the range of interest, they don't take long. Indoor planes typically use P/D ratios in the 1.4 to 1.6 range. Make up a bunch of blades, select the P/D closest to the prop you are trying and just use it. Minor variations from ideal aren't real critical.

Jeff Anderson
Livonia, MI[/quote]

alright thank you
which wood grain would you usually use for props? i dont quite remember, but is it b?
honestly, it's not about the medals. go out there and have fun. make progress, learn a few things, have one heck of a time, because that's all that matters.
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Re: Wright Stuff C

Postby Rossyspsce » February 11th, 2019, 2:17 pm

I remember seeing something ab graphing torque and breaking point for a specific batch of rubber written by one of the information gods, bjt maybe? Does anyone know where it is or if you're the on that wrote it do you mind explaining it again or sending me a link to the original post?

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Re: Wright Stuff C

Postby DarthBuilder » February 12th, 2019, 4:33 am

If I try to glide my plane with the prop it nosedives. I tried changing angle of incidence but still nosedives and my CG is in the same spot as the last plane. What do you guys think so I can try to get it to stall and glide properly?
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Re: Wright Stuff C

Postby klastyioer » February 12th, 2019, 5:24 am

DarthBuilder wrote:If I try to glide my plane with the prop it nosedives. I tried changing angle of incidence but still nosedives and my CG is in the same spot as the last plane. What do you guys think so I can try to get it to stall and glide properly?


what do ur stab posts look like
honestly, it's not about the medals. go out there and have fun. make progress, learn a few things, have one heck of a time, because that's all that matters.
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Re: Wright Stuff C

Postby jander14indoor » February 12th, 2019, 5:50 am

Probably me who recommended testing rubber batches (though I'd NEVER call myself a god, just ask my wife or kids!). Multiple times over the years. Again this year in one of the strings, search for hysteresis maybe, although not sure how consistently I spell that.

Glide testing with prop. Do you have the motor wound slightly so the prop is turning? Not enough to give lift, just enough to reduce drag. If you glide test with a completely unwound motor you WILL get a dive due to the high drag the prop causes.

Jeff Anderson
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Re: Wright Stuff C

Postby bjt4888 » February 12th, 2019, 7:57 am

Rossyspace,

See the 2015 WS forum “Winding” thread for a sample of graphing winding and unwinding torque. See the last post.

The reason to graph or chart unwinding torque is not so much to analyze breaking torque, it’s to understand the torque output over time during flight with that particular motor. This charting of data allows you to determine pretty well a best motor density and length and vintage for a particular propeller type and pitch and airplane design and trim.

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Re: Wright Stuff C

Postby bjt4888 » February 12th, 2019, 8:02 am

Darthbuilder,

Rubber powered indoor airplanes do not glide test well without power. I never do this and I don’t know any top flier that does. Set up the airplane with a known good starting point for trim and fly it powered with the motor. After getting best flights with a particular trim, try an new trim (CG change and then incidence changes, for example) and see if you get improvement in duration.

It’s kind of crazy, in my opinion, that an I powered test flight is allowed by the rules in order to end the “preflight period”. We have a strategy for this.

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Re: Wright Stuff C

Postby bjt4888 » February 12th, 2019, 8:04 am

Typo, should say “...an unpowered...”. Another bad autocorrect.

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Re: Wright Stuff C

Postby Rossyspsce » February 12th, 2019, 10:17 pm

Although this may be an interesting question to ask, is it possible to run two official flights at the same time if running short on the 8-minute flight period? What I mean is your first flight has extended and will most likely end after the 8 minutes, so can I start my second official flight while my first is still in the air, and get times for both?

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Re: Wright Stuff C

Postby Raleway » February 12th, 2019, 10:34 pm

Rossyspsce wrote:Although this may be an interesting question to ask, is it possible to run two official flights at the same time if running short on the 8-minute flight period? What I mean is your first flight has extended and will most likely end after the 8 minutes, so can I start my second official flight while my first is still in the air, and get times for both?


I think you assume that you have then checked in two different planes (which is allowed) and yes, multiple official flights are allowed at the ES discretion (4f). However, I would think no ES would allow that since it would be hard to distinguish which plane has landed first (easy to check later but still an opportunity for ambiguity, which is bad). Furthermore, any collisions in the air would detract from your score, so it would not be in your best interest to fly concurrently in my opinion.
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