I made a battery tray for mine that keeps the battery secure and not stuck to the wing. It works great and is a recommended mod to the Switchback. My ESC is jammed up behind the motor firewall, but there is flexibility in where you mount it.
Switchback Sport
- Thread starter jaredstrees
- Start date
jaredstrees
Well-known member
I was thinking about a tray. I’ve got a bunch of scrap balsa from the build and other projects. I really don’t want to Velcro it to the wing. I covered the whole top and I’d be worried about it tearing the covering. Weather looks terrible for a maiden this weekend, so I’m still looking at Father’s Day weekend. Weather this time of year in Florida is volatile, so hopefully Mother Nature cooperates!
It's looking great!
As for as the orientation markings, I learned on my black and tan one that when up in the air the light and shadow coming through the wing will make it very difficult to see which side is up if it's a symmetrical pattern. That tan covering looks opaque on the ground but with the sun shining through my black stripes were visible clearly from both sides at 50' up in the air. I'd recommend just doing something (maybe white) on one wing or an asymmetrical design so you can always know which is the right and left wing and figure out upside down from that.
As for as the orientation markings, I learned on my black and tan one that when up in the air the light and shadow coming through the wing will make it very difficult to see which side is up if it's a symmetrical pattern. That tan covering looks opaque on the ground but with the sun shining through my black stripes were visible clearly from both sides at 50' up in the air. I'd recommend just doing something (maybe white) on one wing or an asymmetrical design so you can always know which is the right and left wing and figure out upside down from that.
nhk750
Aviation Enthusiast
Nice! I have been learning lately to mount my rx and antennas as far away from all other electronics and any metal for the best reception possible. I use telemetry and it's interesting how other stuff affects frame losses and holds. Off course, you can only do what you can with limited room and cg.
jaredstrees
Well-known member
Thanks guys! And I hadn't thought about the light coming through and making the top and bottom look the same. Hmm, time to back up and punt. The trim I choose is white, so that will help. I generally like symmetry with my plane's markings, but I haven't followed all the rules on this one yet so why start now? If I go asymmetric or only on one wing at least I won't have to match the wings perfectly!
And lights on a future build for sure!
And lights on a future build for sure!
jaredstrees
Well-known member
Not much to report. Lots of family activities over the weekend so not a lot of time spent. I did manage to finish up the canopy and installing the electronics. Just needed to get a little creative. I'll take some pics tonight. Started on the wing trim. I'm still struggling to come up with a design that would look good on only one side of the wing. Any creative people out there who want to throw out some ideas are more than welcome!
jaredstrees
Well-known member
The leading edge strip is almost exactly the way you've got it on the plane just on the underside. I was thinking about checkers melting from it but that may be a bit complicated. I had thought about a design similar but couldn't really visualize it. What program did you use for this? Photoshop? I used that long ago when doing photography work but it's been 15 years. Might have to relearn or learn whatever program you used. Looks like it could be a helpful tool.
Namactual
Elite member
Aye, I use Photoshop. Photoshop Elements actually, which you can still buy outright instead of leasing. GIMP would work as well and it's free, but the interface is a little... alien maybe?
Either way just create a new layer and draw some quick shapes with the polygon lasso. Once you have the shape created use the selection as a mask to paint any color you wish. On the first one I used layer transparency to blend the color layer to the photo so it looked a little more natural. The second red one I just slapped color on it after the fact so it did not blend as nice.
But yeah, it is a very nice tool to help get a visual. I like it because you can play around with designs without actually committing to the first one you would normally do on the real object.
Either way just create a new layer and draw some quick shapes with the polygon lasso. Once you have the shape created use the selection as a mask to paint any color you wish. On the first one I used layer transparency to blend the color layer to the photo so it looked a little more natural. The second red one I just slapped color on it after the fact so it did not blend as nice.
But yeah, it is a very nice tool to help get a visual. I like it because you can play around with designs without actually committing to the first one you would normally do on the real object.
jaredstrees
Well-known member
My God this hobby is taking me down the rabbit hole. First foam, then 3D printing, then balsa. Now it looks like I'm going to have to get back on the photoshop learning track!
jaredstrees
Well-known member
She is done!
Finished her up last night. This has been a great learning experience, and I think for a first time balsa build she came out great. There are a few blemishes here and there, but most of them only I can see. She came in at 10oz, so she's a little overweight, but with the power system she's got I don't think 2oz will make a difference. Apparently I need to learn a little more glue control! If she flies as good as she looks I'll be really happy!
I decided not to do an asymmetrical wing design. After I had the leading edge done I decided that the white trim was visible enough to provide orientation. She wouldn't be flying to far away anyway, she is a small plane. I can add another strip of trim to the wing if I need a bit more definition.
equipment:
Flysky VF8R (A bit overkill, but it is what I had on hand)
HURC 1400kv A2208 motor
Emaxx ES08D servos
Sky Power 20a sbec ESC
Thanks to all of you on the forum! This would have been a lot harder to do if it weren't for everyone's tips, tricks and suggestions. I really appreciate it. I've definitely caught the bug. There is a MM Eva Bipe on the way to me right now.
I hope to maiden this weekend if the weather holds. I'll try for video, but no guarantees. I will be back to post how it went, regardless of the outcome. Thanks!
Finished her up last night. This has been a great learning experience, and I think for a first time balsa build she came out great. There are a few blemishes here and there, but most of them only I can see. She came in at 10oz, so she's a little overweight, but with the power system she's got I don't think 2oz will make a difference. Apparently I need to learn a little more glue control! If she flies as good as she looks I'll be really happy!
I decided not to do an asymmetrical wing design. After I had the leading edge done I decided that the white trim was visible enough to provide orientation. She wouldn't be flying to far away anyway, she is a small plane. I can add another strip of trim to the wing if I need a bit more definition.
equipment:
Flysky VF8R (A bit overkill, but it is what I had on hand)
HURC 1400kv A2208 motor
Emaxx ES08D servos
Sky Power 20a sbec ESC
Thanks to all of you on the forum! This would have been a lot harder to do if it weren't for everyone's tips, tricks and suggestions. I really appreciate it. I've definitely caught the bug. There is a MM Eva Bipe on the way to me right now.
I hope to maiden this weekend if the weather holds. I'll try for video, but no guarantees. I will be back to post how it went, regardless of the outcome. Thanks!
Congrats! She looks great, and I'm sure you'll have a great time flying her
One other idea to help with orientation if it becomes a problem is run a thin black pinstriping line to outline the white trim on the bottom of the wing. The high contrast of straight black and white lines next to each other can really help it visually pop.
Looking forward to the MM Eva Bipe build thread next
One other idea to help with orientation if it becomes a problem is run a thin black pinstriping line to outline the white trim on the bottom of the wing. The high contrast of straight black and white lines next to each other can really help it visually pop.
Looking forward to the MM Eva Bipe build thread next
Try-n-glide
Active member
Looks great. Looking forward to a maiden report!
jaredstrees
Well-known member
Alright. So maiden happened. And there is some good and bad. Sorry, no video. I didn't get a chance to process it last night.
She flies! That's the good part. The bad part is she handled awful. She had a tendency to pitch up and down. She also did not like turning right.
So. I have rates set on the taranis at 50% throw and 50% expo on aileron, rudder and elevator. I've never used that much expo. I may have to limit the throw even more to the elevator. Hopefully this will subdue the pitchiness. As far as the not turning right well I'm a little lost. Both ailerons have good range, as does the rudder. Should I have added in some thrust angle? The instructions did not call for it. After that I'm a little at a loss.
Of course, I had a few issues with my little stick as well (and I never have issues with that plane), so some of this may have been nerves. It was also hot as ****, so it was a bit uncomfortable to be outside nervous and dripping. Wind was calm, less than 2mph. Orientation was ok, it was overcast so everything was a little washed out, but I think on sunny days I'll be able to see her just fine.She did a ROG takeoff and climbed nicely, but that was about it. I managed to get it down fine twice, but on the third it did a pitch into the ground from 2 feet. No major damage, but I'll have to repair the landing gear and a broken prop. Everything else was fine.
Any suggestions are welcome!
She flies! That's the good part. The bad part is she handled awful. She had a tendency to pitch up and down. She also did not like turning right.
So. I have rates set on the taranis at 50% throw and 50% expo on aileron, rudder and elevator. I've never used that much expo. I may have to limit the throw even more to the elevator. Hopefully this will subdue the pitchiness. As far as the not turning right well I'm a little lost. Both ailerons have good range, as does the rudder. Should I have added in some thrust angle? The instructions did not call for it. After that I'm a little at a loss.
Of course, I had a few issues with my little stick as well (and I never have issues with that plane), so some of this may have been nerves. It was also hot as ****, so it was a bit uncomfortable to be outside nervous and dripping. Wind was calm, less than 2mph. Orientation was ok, it was overcast so everything was a little washed out, but I think on sunny days I'll be able to see her just fine.She did a ROG takeoff and climbed nicely, but that was about it. I managed to get it down fine twice, but on the third it did a pitch into the ground from 2 feet. No major damage, but I'll have to repair the landing gear and a broken prop. Everything else was fine.
Any suggestions are welcome!
Try-n-glide
Active member
Sounds like the CG is too far back? Most MM planes are so light a small move on the battery changes the CG noticeably.
I'd agree with pushing the CG forward a 1/2" at a time to tame the pitchieness. Once that's more under control let's take the turning problem apart a bit more.
First, check for flexing in the control linkage to the rudder. Especially if it's the direction that pushes the wire that it doesn't want to turn.
Then from 2 mistakes high, trim her to fly straight at about 50% or 75% throttle. Then on a straight pass upwind and down wind, chop the throttle quickly and see what happens. If it consistently turns to the same side rather than continuing straight, then you've got a thrust angle thing going on that the trimming was overcoming. Try adding a small washer between the firewall and motor mount to force in a little right thrust and try again. If it turns to one side or the other but not consistently, it's probably too windy up at altitude for this test.
Once we're good there, try doing flat rudder only turns both left and right - if they don't act the same, then there is probably a drag difference on one side of the plane and it is probably easiest to adjust the throws to deal with it.
First, check for flexing in the control linkage to the rudder. Especially if it's the direction that pushes the wire that it doesn't want to turn.
Then from 2 mistakes high, trim her to fly straight at about 50% or 75% throttle. Then on a straight pass upwind and down wind, chop the throttle quickly and see what happens. If it consistently turns to the same side rather than continuing straight, then you've got a thrust angle thing going on that the trimming was overcoming. Try adding a small washer between the firewall and motor mount to force in a little right thrust and try again. If it turns to one side or the other but not consistently, it's probably too windy up at altitude for this test.
Once we're good there, try doing flat rudder only turns both left and right - if they don't act the same, then there is probably a drag difference on one side of the plane and it is probably easiest to adjust the throws to deal with it.
Hmmm... I agree with others that it may simply be too tail-heavy right now. I noticed my standard wing with dihedral is far more forgiving than the "3D" wing without any dihedral. In fact, the first time I flew the 3D wing I had a lot of the same problems as my battery was too far back giving me excess tail weight. After moving it forward (all the way to the formers) it evened out and is now a fun and spirited plane.
I assume you have good aileron deflection while the plane is actually flying, and the pushrod isn't slipping or bending? The stock setup designed by MM is plenty strong unless you're getting silly with the power & weight, which doesn't sound like the problem. With the Switchback and Dandy (same basic design) I've built they've both used the stock "stick" mount which I think gives 0* thrust changes, and both fly well.
For general flying the throws don't need to be very large. I've got triple rates set to go from mild to wild, all with about 25% expo.
I assume you have good aileron deflection while the plane is actually flying, and the pushrod isn't slipping or bending? The stock setup designed by MM is plenty strong unless you're getting silly with the power & weight, which doesn't sound like the problem. With the Switchback and Dandy (same basic design) I've built they've both used the stock "stick" mount which I think gives 0* thrust changes, and both fly well.
For general flying the throws don't need to be very large. I've got triple rates set to go from mild to wild, all with about 25% expo.
