FF2017 Int. Racers: Folkerts Speed King SK-3 "Jupiter"
- Thread starter Mid7night
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Tench745
Master member
On anything pre-WWII I would consider rudder a necessity. All the earlier books I've read they talk about kicking in rudder to turn, and ailerons are basically treated as secondary, like they're only there to keep you level. I suspect early planes are all designed with that intent in mind. But that's just a guess.
+1
Earlier airplanes MUST be flown coordinated. Not doing so is aviation nightmare fuel IMHO.
Earlier airplanes MUST be flown coordinated. Not doing so is aviation nightmare fuel IMHO.
Ok OK! I get it! Rudder = Required! 
Also, @Aviator08: The wind is fickle at my field, but I definitely threw into the wind both times...however the first launch had several other problems that quickly threw it off-axis. The second flight went more true where I threw, which allowed the 'flight' to uncover my yaw-instability and inadequate-control issues.
Also, @Aviator08: The wind is fickle at my field, but I definitely threw into the wind both times...however the first launch had several other problems that quickly threw it off-axis. The second flight went more true where I threw, which allowed the 'flight' to uncover my yaw-instability and inadequate-control issues.
Ok OK! I get it! Rudder = Required!
Don't give into the bullying and 'wisdom of the crowds' arguments! You can make it work without a rudder!! Only need about 10 more prototypes a few more bent motors, and a time extension to FF2024, but don't let that stop you!
FAI-F1D
Free Flight Indoorist
I've watched the maiden and re-maiden videos twice now, and I think I know at least a few components of them. 1 is that the yawing and rolling are coupled. This is a clear indicator of an undersized vertical stab (Dutch roll tendency). Secondly, however, the phenomenon seems to be triggered by roll inputs at high angles of attack, which would indicate the infamous tip stall. That isn't a problem you necessarily need to deal with other than that it indicates a flight regime to stay away from. If you remember, I expressed concern about wingloading on facebook. This is the reason. I've had the same nasty razor edge with a couple of Hobbyking's products, most notably the Kinetic. I'm not sure that washing out the wingtips will make it go away completely. Mainly it's time to make sure you get the model well up to speed and make sure your elevator throws aren't excessive. Also, you may be able to further reduce the tendency during trimming by dropping the prop pitch. That will give better acceleration and smoother slipstream.
Back in business!
Still need to glue the wing in, but everything else is hooked up and ready.
I changed the fuse layout on this one, so instead of stuffing everything in a hole through the belly, the whole top deck is just a cover and everything sits on top. Makes it much easier to service everything.
Still need to glue the wing in, but everything else is hooked up and ready.
I changed the fuse layout on this one, so instead of stuffing everything in a hole through the belly, the whole top deck is just a cover and everything sits on top. Makes it much easier to service everything.
Userofmuchtape&glue
Posted a thousand or more times
Nice! I can't wait for a successful re-maiden!
Thanks guys! I also hope the next remaiden goes better than the last two.
For this third flight, a few things will be different: Full-span ailerons (no flaps), functional rudder, and I plan on starting with an 8x6 prop instead of the racing-pitch 8x10. Should still have more than enough thrust, but perhaps that will help reduce the torque-roll-of-death.
I would like to mix in some rudder with the throttle channel....anyone have experience with this, what percentage or schedule would you recommend? I'm on Taranis, so I have lots of options.
For this third flight, a few things will be different: Full-span ailerons (no flaps), functional rudder, and I plan on starting with an 8x6 prop instead of the racing-pitch 8x10. Should still have more than enough thrust, but perhaps that will help reduce the torque-roll-of-death.
I would like to mix in some rudder with the throttle channel....anyone have experience with this, what percentage or schedule would you recommend? I'm on Taranis, so I have lots of options.
LOL!! That's exactly what I ended up doing on my flights so far too
I put my latches in too far from the ends of my temporary top and it started to flap around, so every time I loaded up a battery I'd tape the hatch down. Crashing usually opened up access to the battery again :black_eyed:
Remaiden SUCCESS!! WOOHOO! I was even able to bring it back home INTACT! (that is not a normal occurrence with my flights)
First important ProTip: Don't maiden a handlaunch racer at full throttle. 1/2 should do, then increase throughout the flight.
Just launching this at half throttle, and not punching it right out of my hand, that alone reduced the torque roll that I had to deal with on takeoff.
Don't get me wrong; torque roll is still there in power, but it's a lot more manageable at low throttle settings close to the ground.
The first flight of the day was on a slower 8x6 prop, not the 8x10 pattern prop. I dialed in a bit of right rudder trim, and by the end of the flight I added a little more. Other than a little rudder trim, this plane was incredibly well behaved! The tail moment is MASSIVELY long though, so I found myself on low rates for elevator and still didn't need it all.
ProTip #2: If it goes fast, you need a LOT LESS control surface throw than you may think.
The second flight was the exact same setup, except I swapped on the 8x10 prop; I wanted to compare the speed logs and amps between the two props. Unfortunately, for some reason, my pitot tube sensor didn't work properly. So I have zero numerical comparisons to make, but we CAN look at the videos.
Flight 1:
Flight 2
Based on all your calibrated eyes, do you think the 8x10 actually went faster than the 8x6? I'm honestly not sure.... But I'm happy I have an airplane that will fly again!
First important ProTip: Don't maiden a handlaunch racer at full throttle. 1/2 should do, then increase throughout the flight.
Just launching this at half throttle, and not punching it right out of my hand, that alone reduced the torque roll that I had to deal with on takeoff.
Don't get me wrong; torque roll is still there in power, but it's a lot more manageable at low throttle settings close to the ground.
The first flight of the day was on a slower 8x6 prop, not the 8x10 pattern prop. I dialed in a bit of right rudder trim, and by the end of the flight I added a little more. Other than a little rudder trim, this plane was incredibly well behaved! The tail moment is MASSIVELY long though, so I found myself on low rates for elevator and still didn't need it all.
ProTip #2: If it goes fast, you need a LOT LESS control surface throw than you may think.
The second flight was the exact same setup, except I swapped on the 8x10 prop; I wanted to compare the speed logs and amps between the two props. Unfortunately, for some reason, my pitot tube sensor didn't work properly. So I have zero numerical comparisons to make, but we CAN look at the videos.
Flight 1:
Flight 2
Based on all your calibrated eyes, do you think the 8x10 actually went faster than the 8x6? I'm honestly not sure.... But I'm happy I have an airplane that will fly again!
Sweet! Looks pretty sharp carving around there! If you feel the urge during the next video chatter along and narrate the flight it would help the rest of us have more to talk smack about.
LOL, I'll try to be more talkative next time.
Yeah, she's definitely a quick one. I'm mostly just pleased at how well she tracked once dialed in.
So, I guess I'm really not cut out for public speaking...I flew again on Friday, and talked a little at the beginning before launching, but then I just forgot to talk the entire time. Oh well, the flights looked basically the same as the first two, but this time I got my telemetry to work, so I now have DATA to compare the two different props! Like I said, the second two flights looked basically the same as the first two, so I won't be posting the video (not right away at least, maybe I'll post a cut-down version later), but I do want to share the graphs of the data.
Speed in MPH is plotted against the axis on the right. Power and Altitude share the left axis. I broke 109mph with the 8x10, and only 92mph on the 8x6; I guess the 8x10 really is faster!
Flight 1, 8x10 prop:
Flight 2, 8x6 prop:
Oh well, the flights looked basically the same as the first two, but this time I got my telemetry to work, so I now have DATA to compare the two different props! Like I said, the second two flights looked basically the same as the first two, so I won't be posting the video (not right away at least, maybe I'll post a cut-down version later), but I do want to share the graphs of the data.Speed in MPH is plotted against the axis on the right. Power and Altitude share the left axis. I broke 109mph with the 8x10, and only 92mph on the 8x6; I guess the 8x10 really is faster!
Flight 1, 8x10 prop:
Flight 2, 8x6 prop:
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