NewZee
Member
Maybe its just me but how could you not have tried it!!! I think the best way to see if your motor has the B**LS is to take off the landing gear throttle up and chuck it! I bet it flys!
WIP: Swappable Piper PA-12 Super Cruiser
- Thread starter thatjoshguy
- Start date
Maybe its just me but how could you not have tried it!!! I think the best way to see if your motor has the B**LS is to take off the landing gear throttle up and chuck it! I bet it flys!
thatjoshguy
Senior Member
2% fear of failure, 98% fear of 12mph winds with 15mph gusts. Friday was the best day we have had so far, and it wasn't ready yet
The weight of the plane will not affect amp draw at all, the only thing weight will do is keep you on the ground. The calculator asks for weight so it can determine thrust to weight factors. And the most amp draw will happen at full throttle. Your prop speed and size are going to be the main determining factors in amp draw. Too large a prop, or too steep in pitch, will cause the motor to try to work harder than it can and will make the motor draw too many amps. Basically the motor will draw amps based on load, the prop is what determines the load. The faster you spin the prop, the more load it will create. Same with pitch and diameter, more is more load and will make the motor draw more amps. The ESC and the battery will only supply the motor with what the motor asks for, so as long as the prop is sized correctly to the motor, and that combo is sufficient enough to pull the weight of your plane, the only thing left is to add a battery and ESC that will safely supply the motor with what it needs.
I don't know if that helps or if it makes it more confusing...
Last edited:
thatjoshguy
Senior Member
That cleared it up perfectly, thank you! Looks like this bird may fly after all, just need a clear day to try
NewZee
Member
2% fear of failure, 98% fear of 12mph winds with 15mph gusts. Friday was the best day we have had so far, and it wasn't ready yet
You are much smarter than me!
thatjoshguy
Senior Member
LOL, not that smart... I took the Old Fogey out on Saturday and was lucky it came home at all.
NewZee
Member
I know my Old Fogey is a real handful in the wind, flys around like a kite!
thatjoshguy
Senior Member
Well I maidened, if you can call it that. Two things: plane is tail heavy even with battery all the way forward, and the 8040 prop just wasn't cutting it. Plane is in two pieces now, but salvageable. Didn't catch it until after I crashed, but the prop was pulling loose from the prop saver at high throttle and going off balance, so there was a sudden loss of thrust. Two launches, both immediately went nose up, stall left, nose in the grass. Second was hard enough to rip the wing off. Good thing I had the FTFlyer with me to make sure the trip wasn't a total waste.
NewZee
Member
Sorry to hear that hope you can rebuild her and get the CG further forward? maybe try a ground take off to eliminate any torque roll? I fight the same thing every time I fly my Cub? and need some right rudder on take off.
thatjoshguy
Senior Member
Yes, I can rebuild. This time I'll be a little more patient and get the ground control right so I can take off properly. Should also have the larger props this afternoon, so I'll see if they fit the prop saver better. Won't get to fly for a while, so I have time.
thatjoshguy
Senior Member
I've gone back to the drawing board to address standing issues with this design vs. simply gluing it all back together.
for those with SketchUp, here is a copy of the plans v2.
https://www.dropbox.com/s/6f1c66vbmah2gtw/piper%20pa-12%20v2.skp
I've simplified the build a good deal actually. I've removed the curved hood on the front and opted instead for flat surfaces. I don't think it takes away from the looks that much. That, and the removal of all those glue tabs should make for an easier build. They didn't seem to add that much strength. I've also opened up the top of the rear under the turtledeck to reduce weight.
I've also increased the wing dihedral from 3 degrees to 6, and modified the elevator for a little more strength.
Last night I built some landing gear using piano wire and a coffee stir with another piece of wire through it to act as an axle. It's sturdy yet flexible, and it looks the part. I may try again tonight to see if I can simply solder a wire across the gear as I have shown in this file, and have the wheels spin independently of one another. I think if I use lighter gauge wire I'll save some weight, as well as gain some flex while retaining strength.
for those with SketchUp, here is a copy of the plans v2.
https://www.dropbox.com/s/6f1c66vbmah2gtw/piper%20pa-12%20v2.skp
I've simplified the build a good deal actually. I've removed the curved hood on the front and opted instead for flat surfaces. I don't think it takes away from the looks that much. That, and the removal of all those glue tabs should make for an easier build. They didn't seem to add that much strength. I've also opened up the top of the rear under the turtledeck to reduce weight.
I've also increased the wing dihedral from 3 degrees to 6, and modified the elevator for a little more strength.
Last night I built some landing gear using piano wire and a coffee stir with another piece of wire through it to act as an axle. It's sturdy yet flexible, and it looks the part. I may try again tonight to see if I can simply solder a wire across the gear as I have shown in this file, and have the wheels spin independently of one another. I think if I use lighter gauge wire I'll save some weight, as well as gain some flex while retaining strength.
thatjoshguy
Senior Member
thatjoshguy
Senior Member
I have yet to find a decent way to do it in free SketchUp, but you can do it in SketchUp Pro, even with the free trial.
I flatten the model first using the Flatterly plugin, then set the camera to top view, Parallel Projection. In Pro you can export a 2d image and choose AutoCAD DXF. I then place into Adobe Illustrator, setting the scale of 1 unit = 1 inch, then setting line width to 1.
I flatten the model first using the Flatterly plugin, then set the camera to top view, Parallel Projection. In Pro you can export a 2d image and choose AutoCAD DXF. I then place into Adobe Illustrator, setting the scale of 1 unit = 1 inch, then setting line width to 1.
thatjoshguy
Senior Member
does flattery work on the 2014 version? I can't seem to get it.
Sorry If I am pestering you.
Not pestering me at all, the more people who know how to do this the better!
Download Flattery from here: http://www.pumpkinpirate.info/flattery/
Then change the extension from .ZIP to .RBZ
Load sketchup, and go to Window -> Preferences. Click Extensions, then Install Extension. Choose the .RBZ file we just renamed and it should install. May need to restart Sketchup to see it, may also need to right-click the toolbar and and select Flattery to see the tools.
VAND3R
Member
I have tryed all of the above and I am still not getting the toolbar.
I will try downgrading to sketchup 2008 and see if it works, I couldn't find any documentation on flattery working on 2014.
Thanks!
Similar threads
