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FT What Did You Do RC Today : Caution Offtopic At All Times

mrjdstewart

Well-known member
so the F-22 flew like a dream. floated right out, needed zero trim, only issue was i had my thrust diff backwards on the first flight. swapped the 2 motor wires in the rx and next flight all was good. this thing flies great and has a pretty amazing glide slope which is good because it sucked a 4S-1300 in just under 3 mins. i think i may try a 1800 and see if i can at least have a solid 3.

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sorry for crappy camera work.


laters,

me :cool:
 
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Piotrsko

Well-known member
Got my C class motor installed in place of the heli inrunner, got a decent prop adapter, put an 11" prop on and fired it up. Good gracious, wasn't expecting THAT much thrust, almost had a first flight in the sunroom. The bronco may actually do a prop stand.
 
If i am trying to build something along the lines of a 25" wingspan 12" length race wing and i have a 30Amp esc and i have a 2207 1700kv motor should i buy another motor? I am hoping to be able to hit 70-100Mph but have a decent flight time, is this possible? I am going to run on a 3s 850 or 1800mah whatever will work better. What shape should i try for the main wing for a high speed FPV wing? What rudder/winglet configuration should i have? I am hoping to be able to keep the same ESC, Battery, and prop but am willing to buy a few things. Thanks!
 

Hai-Lee

Old and Bold RC PILOT
If i am trying to build something along the lines of a 25" wingspan 12" length race wing and i have a 30Amp esc and i have a 2207 1700kv motor should i buy another motor? I am hoping to be able to hit 70-100Mph but have a decent flight time, is this possible? I am going to run on a 3s 850 or 1800mah whatever will work better. What shape should i try for the main wing for a high speed FPV wing? What rudder/winglet configuration should i have? I am hoping to be able to keep the same ESC, Battery, and prop but am willing to buy a few things. Thanks!
Where do I start?
Firstly you do require as little wing area as possible but it must be able to support the craft's all up weight and quite a few "G"s as well.

As much as is possible of the electrics and battery should be buried out of the airflow to reduce the drag.

The motor will need to provide a great deal of thrust and so you may need a motor capable of not only high kV but also greater voltage.
To double speed you will need to have 8 times the power/thrust.

A symmetrical wing profile/airfoil will give the least drag for its area or perhaps even a truly reflexed airfoil. Wing thickness can be quite high if the cord is long enough but then you will need some wing tip fences to keep the lift figures adequate.

In order to have a greater wing area, shorter span, and roll stability at high speed a wing sweep angle is recommended though that does bring balance issues if the sweep angle is too great! TO bring the CG forward you could go with either circular wing sweep or even a truncated oval shape.

Finally it should be a tractor design, (motor in the front), with a spinner for best clear air for the prop to develop its maximum thrust!

If you have some draft design I may be able to help you refine it a little!

have fun!
 

Wildthing

Well-known member
To add to Hai-Lee's post, limiting yourself to 3S and that small esc will be you stopper. If your craft is small, aerodynamic and light enough plus depending if that motor can handle 4S which then possibly means a larger esc you could have a chance.
 

Wildthing

Well-known member
Well last time out for the combat wars I had one battery give out 30 seconds into flight, 2200 3S Zippy battery, today I ran and tested it , #3 cell loses voltage really quick, let it sit for 10 seconds and it is right back up with the other cells. So let's get rid of that bad cell and make myself a 2S battery. :) I have never bought a 2S battery but now I have one. :)
 
Well last time out for the combat wars I had one battery give out 30 seconds into flight, 2200 3S Zippy battery, today I ran and tested it , #3 cell loses voltage really quick, let it sit for 10 seconds and it is right back up with the other cells. So let's get rid of that bad cell and make myself a 2S battery. :) I have never bought a 2S battery but now I have one. :)
That 2s might be good for a glider project...

Or a endurance type platform.
 
I was feeling kinda down today because of many projects that dont go as fast as I would want and other stuff (guess it isnt my day) so I started yet another side project that I will never finish.
Little 9 cylinders radial engine, designed to be mostly 3d printed and run on air (but could be made into a real thing with a cnc probably)
I also want to design it to be stackable to have a 18 cylinders or even more radial, there is no real practical use other than having a nice sound but I still have to finish it, took me a couple hours so far.
 

mrjdstewart

Well-known member
all finished except Tx programing for the thrust diff. came in a little heavier than i had hoped for but should still be close to 3-1 depending upon how the motors do with the props in real life. no matter, it will be fun regardless. :LOL:

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i also finished prepping this guy. he is done except programing.

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and since i was bored i thought i would highly modify my delta wing to accommodate a 70mm EDF.

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then i realized i could get the same thrust out of 2 EDF's @ half the weight and be able to add diff thrust.

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i have built, and have had many others build this wing, and everyone LUV'S it! PLANS HERE it's usually a "prop in slot" with a 2205 red bottom, 20A esc, 6x4.5 and it is an angel and a beast. huge flight envelope and $1.50 in fuselage. can't wait to see what it does as an EDF.

so if all goes well we will have another 3 maiden saturday!

laters,

me :cool:
 

Vimana89

Well-known member
Flew my RETjet mk2 second prototype today. I used a graupner motor rated for CCW on a clockwise pusher sort of out of ignorance but I don't have many motors left. Worked poorly and sluggish but flew,and I think burnt the motor out. I did a transplant to my FT radial of the same size and power...the problem with that motor is the shaft is too long, maybe a factory defect, so I had to use washers to fit it snug on the prop. I'll have to ask around and address this issue more later. She flew after the motor swap, but wind picked up so I had to call it early. Will test more tomorrow.
 

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Vimana89

Well-known member
I took the RETjet out this morning after decorating it with some more duck mirror last night(thin,not like duct tape). I got quite a bit of flying in, with some sketchy moments, but I'm getting the hang of it. A couple small scrapes and dings but once again she's ready to go home in one piece.
 

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mrjdstewart

Well-known member
so the 3 plane maiden is down the drain. the durafly BF-109 is nothing but issues. thanks hobby king. :rolleyes::LOL::ROFLMAO::sneaky:

but, i do have the wing and the hacker ready to go. those and the F-22 on a bigger battery should be enough to please the crowds.

i really am looking forward to seeing how the wing does. i have built prob 20 or more of these in various configurations, but only 1 other with rudder (yaw) controls. it was a great wing but that was more to the airfoil i built into rather than the addition of yaw control. after that i just stopped adding rudders and just went "yank and bank" delta mix. from what i can see from initial tests, i think this one w thrust diff may be the winner and actually provide a decent amount of yaw. not only do we have the thrust diff, but vert stabs have been reduced, skids on bottom significantly reduced to allow for less resistance to yaw affect. or, maybe i'm just crazy? :LOL:

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3D designed and printed pods.

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will try and get video of everything tomorrow.

laters,

me :cool:
 

Vimana89

Well-known member
Went out again with the RETjet. Was getting a great video with lots of stuff when some some bozo off-roading comes screaming right down dirt trail I'm standing by and launching from. I step off the trail by other than that my eyes are on my plane. I thought it was a dirt bike but as he goes by it's a car or truck(paying attention to plane). Whoever it was seemed to purposely rev up for more loud annoyingness and added dust as they passed by for the sole purpose of messing me up, but I kept my eyes on the plane. Great flying but as that vehicle passes by it becomes no longer a family friendly video because I use some coarse language audible enough for the camera to get it for sure.