FlyerInStyle
Elite member
wow those are actually really nice plans. will look into it. thanks. do you think I could make this half the size, and maybe use a umx brick?
Airbender sailplane scratchbuild
- Thread starter speedbirdted
- Start date
speedbirdted
Legendary member
Dear god no, don't even try that. Cutting all the dimensions in half would result in some really wonky wood sizes. You would need to use 3/64 balsa for a lot of things, which is totally impossible to get. Not to mention you'd need 1/64 balsa for the wing ribs which is just hell to work with. (trust me I've tried) If you were to say, change the dimensions of some things to more practical sizes - as an example, changing the longerons to 1/16 - would require redesigning and respacing the slots on every single fuselage former and at this point you might as well just redo the whole plan to make it easier, which is something I have neither the time nor inclination to do.
A UMX brick won't even fit if you scale it to half. Even at full scale, the fuselage is so narrow that a UMX brick barely fits into it. I did actually consider using one of the ones that supports 2s and BL motors, like the one in the UMX Timber, but I already had servos that fit on hand (and plus they're easier to adjust and center better)
Gonna use the 020 power pack from willy nillies. My WN Q-tee has the exact same setup, and it hauls its heavy butt around with authority. For the battery I'm going to use a 350 2s because it's the only size I've got that will actually fit.
No folding prop; I think the extra weight penalty would negate any aerodynamic advantage on such a lightweight airframe. I do have another sub 250g glider that has a folding propeller, and I've flown it both with and without it and don't notice any difference in glide performance between the two.
I've made quite a bit of good progress in the last few days. For a bit, I thought this wouldn't be done in time for B250 but it looks like I can do it. It'll be tight - I might end up doing the maiden Friday morning before I load everything up and strike out for Muncie. The annoying task of shaping the wing trailing edge is at least finished. I think this is the last time I'll ever do this with the trailing edge installed on the wing, at least on a wing with this many ribs. You have to protect each rib with tape to prevent it being sanded down accidentally, which is annoying to do, and sometimes when the tape is removed the ribs can be damaged, especially if the ribs are very thin.
The wing was otherwise complete, so it's tissue time. I stuck down the tissue with Elmer's glue stick, and shrank it with a mix of 90% water and 10% Eze-dope. Unfortunately, it doesn't seem to work very well in my HVLP gun (I just discovered my airbrush got broken in the move
) so I had to brush it on with a foam brush as gently as possible. It worked out decently well, but was a pain to do because the wet strength of this yellow tissue is VERY poor. Push on it even a little too hard or get it too wet and it just gives up and holes are created. Even shifting it over a wing rib results in splits and holes a lot of the time. I had to strip and recover the right panel because it kept splitting during shrinking cause I was too heavy with the dope.
Completed wing, sans tips. These will get a separate piece, to minimize wrinkles. Of course, I had to drop something on the wing and punch a little hole in it. I think I'll just patch this and claim it to be crash damage to anyone that asks.
Tail bits were also covered. I set them up with fishing line hinges. I glued them in with CA on one side, and Titebond on the other side. This was so the glue would not discolor the tissue when gluing the two surfaces together. They just need control horns added which I'll make from either old credit cards or 1/32 plywood.
As per usual practice, once the fuselage is covered, the tail feathers will be glued on.
Weight so far. Not too shabby! This is not including the pushrods or fuselage covering, so add 10g, but everything else is there.
I might have to consider designing a sub-250 2-meter ship again...
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danskis
Master member
Thanks for the reply. Great work - my kit isn't coming out that nice. Just curious, instead of brushing on the dope/water mixture why didn't you spray the tissue with a light mist of water using a spray bottle and then later brush on dope or skip the dope and use a light mist of polyurathane?
FlyerInStyle
Elite member
so you are saying that full thing full size could be powered by umx brick? I am using a copy version of it. it has 3.7 or 1.7g servos I think the 3.7 but not sure. in comparison of servo size to reciever they look a little smaller than yours.Dear god no, don't even try that. Cutting all the dimensions in half would result in some really wonky wood sizes. You would need to use 3/64 balsa for a lot of things, which is totally impossible to get. Not to mention you'd need 1/64 balsa for the wing ribs which is just hell to work with. (trust me I've tried) If you were to say, change the dimensions of some things to more practical sizes - as an example, changing the longerons to 1/16 - would require redesigning and respacing the slots on every single fuselage former and at this point you might as well just redo the whole plan to make it easier, which is something I have neither the time nor inclination to do.
A UMX brick won't even fit if you scale it to half. Even at full scale, the fuselage is so narrow that a UMX brick barely fits into it. I did actually consider using one of the ones that supports 2s and BL motors, like the one in the UMX Timber, but I already had servos that fit on hand (and plus they're easier to adjust and center better)
Gonna use the 020 power pack from willy nillies. My WN Q-tee has the exact same setup, and it hauls its heavy butt around with authority. For the battery I'm going to use a 350 2s because it's the only size I've got that will actually fit.
No folding prop; I think the extra weight penalty would negate any aerodynamic advantage on such a lightweight airframe. I do have another sub 250g glider that has a folding propeller, and I've flown it both with and without it and don't notice any difference in glide performance between the two.
I've made quite a bit of good progress in the last few days. For a bit, I thought this wouldn't be done in time for B250 but it looks like I can do it. It'll be tight - I might end up doing the maiden Friday morning before I load everything up and strike out for Muncie. The annoying task of shaping the wing trailing edge is at least finished. I think this is the last time I'll ever do this with the trailing edge installed on the wing, at least on a wing with this many ribs. You have to protect each rib with tape to prevent it being sanded down accidentally, which is annoying to do, and sometimes when the tape is removed the ribs can be damaged, especially if the ribs are very thin.
View attachment 200931
The wing was otherwise complete, so it's tissue time. I stuck down the tissue with Elmer's glue stick, and shrank it with a mix of 90% water and 10% Eze-dope. Unfortunately, it doesn't seem to work very well in my HVLP gun (I just discovered my airbrush got broken in the move
View attachment 200932
Completed wing, sans tips. These will get a separate piece, to minimize wrinkles. Of course, I had to drop something on the wing and punch a little hole in it. I think I'll just patch this and claim it to be crash damage to anyone that asks.
View attachment 200934
Tail bits were also covered. I set them up with fishing line hinges. I glued them in with CA on one side, and Titebond on the other side. This was so the glue would not discolor the tissue when gluing the two surfaces together. They just need control horns added which I'll make from either old credit cards or 1/32 plywood.
As per usual practice, once the fuselage is covered, the tail feathers will be glued on.
View attachment 200935
Weight so far. Not too shabby! This is not including the pushrods or fuselage covering, so add 10g, but everything else is there.
I might have to consider designing a sub-250 2-meter ship again...
View attachment 200937
cyclone3350
Master member
I have been stick and tissue for may years myself. I am with you on the patch. I can say that once you get as far as you have done on the wings, there is no way in H-E 2X hockey sticks that I would redo a panel for that size hole.Dear god no, don't even try that. Cutting all the dimensions in half would result in some really wonky wood sizes. You would need to use 3/64 balsa for a lot of things, which is totally impossible to get. Not to mention you'd need 1/64 balsa for the wing ribs which is just hell to work with. (trust me I've tried) If you were to say, change the dimensions of some things to more practical sizes - as an example, changing the longerons to 1/16 - would require redesigning and respacing the slots on every single fuselage former and at this point you might as well just redo the whole plan to make it easier, which is something I have neither the time nor inclination to do.
A UMX brick won't even fit if you scale it to half. Even at full scale, the fuselage is so narrow that a UMX brick barely fits into it. I did actually consider using one of the ones that supports 2s and BL motors, like the one in the UMX Timber, but I already had servos that fit on hand (and plus they're easier to adjust and center better)
Gonna use the 020 power pack from willy nillies. My WN Q-tee has the exact same setup, and it hauls its heavy butt around with authority. For the battery I'm going to use a 350 2s because it's the only size I've got that will actually fit.
No folding prop; I think the extra weight penalty would negate any aerodynamic advantage on such a lightweight airframe. I do have another sub 250g glider that has a folding propeller, and I've flown it both with and without it and don't notice any difference in glide performance between the two.
I've made quite a bit of good progress in the last few days. For a bit, I thought this wouldn't be done in time for B250 but it looks like I can do it. It'll be tight - I might end up doing the maiden Friday morning before I load everything up and strike out for Muncie. The annoying task of shaping the wing trailing edge is at least finished. I think this is the last time I'll ever do this with the trailing edge installed on the wing, at least on a wing with this many ribs. You have to protect each rib with tape to prevent it being sanded down accidentally, which is annoying to do, and sometimes when the tape is removed the ribs can be damaged, especially if the ribs are very thin.
View attachment 200931
The wing was otherwise complete, so it's tissue time. I stuck down the tissue with Elmer's glue stick, and shrank it with a mix of 90% water and 10% Eze-dope. Unfortunately, it doesn't seem to work very well in my HVLP gun (I just discovered my airbrush got broken in the move
View attachment 200932
Completed wing, sans tips. These will get a separate piece, to minimize wrinkles. Of course, I had to drop something on the wing and punch a little hole in it. I think I'll just patch this and claim it to be crash damage to anyone that asks.
View attachment 200934
Tail bits were also covered. I set them up with fishing line hinges. I glued them in with CA on one side, and Titebond on the other side. This was so the glue would not discolor the tissue when gluing the two surfaces together. They just need control horns added which I'll make from either old credit cards or 1/32 plywood.
As per usual practice, once the fuselage is covered, the tail feathers will be glued on.
View attachment 200935
Weight so far. Not too shabby! This is not including the pushrods or fuselage covering, so add 10g, but everything else is there.
I might have to consider designing a sub-250 2-meter ship again...
View attachment 200937
speedbirdted
Legendary member
Is it one of the boards with the integrated servos that look like normal servos or are they the linear actuator type? I ask because the only boards I've found that have linears that are worth a crap are the genuine Spektrum ones. The clones tend to have problems with either the linears sticking or not centering right after a short amount of time. If they have the more normal integrated servos, they will probably behave better though some testing should still be done.
Either way if you do something like that you will probably have to redesign at least the servo tray. The cutouts in the solid section of former 5 are meant to accommodate rails to mount servos to; I'm not sure if this will work exactly with an integrated board but it should be figured out before you start sticking wood together.
In other words I've been cramming like crazy getting this done. All the electronics were mounted and pushrods were routed, so it's time to cover the fuselage. I'm going to use solid green - I don't care much for complex color schemes anyhow. Only really interesting thing here was the order in which I covered the fuselage. The top was done, and after this the motor was mounted along with the electronics installed and pushrods put in.
Pretty soon I encountered a problem: there was no way to put the bent pushrod in and have it come up through the top of the fuselage like I wanted. I also couldn't use heatshrink and CA because I can't use a heat gun (because paper maybe kinda sorta burns a little when exposed to high temperatures, but don't quote me on that) The workaround to this I found was to put a hole in a stick parallel to the grain, slide the pushrod ends into the stick, then fill it with thin CA. I thought it might not work as well, but it's plenty strong.
This is getting dangerously close to looking like it might actually fly. The dope is still drying here, because I couldn't be bothered to wait for it to (it's drying as I type this)
I left one bay on the tail uncovered; this will get covered after the maiden. It's there so I can stick weights in there if I have to. It feels very nose heavy even with the battery as rearward as it can go right now.
I don't think I'm going to build a hatch after all. It's just extra weight and I doubt the little bit of extra drag not having it causes will be any real concern. Only thing I have left to do now is glue the tail on, cover the wingtips, and make/mount some control horns. All tasks I can hopefully do tomorrow, and then it's flight time.
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TooJung2Die
Master member
Beautiful. It's looking like something capable of flight. Here's hoping for a beautiful day with no wind for the maiden flight. I use a soldering iron on heat shrink in tight places like inside the fuselage.
FlyerInStyle
Elite member
it is from a micro plane like the umx ones except the servos are seperate. the plane its from is called a p707. sold on amazon. its an rtf. the motor esc in the board broke, so that is why I am looking for a glider.
speedbirdted
Legendary member
Got the tips covered, control horns made and mounted, and hooked up all the linkages. We're done!
AUW with a 360 2s battery, and 1/8 ounce of tail weight. I found that's what it needed for a perfect CG. I expected it to want a more aft CG after all, as that's what tends to happen when you have lots of rearward sweep in your wings.
Have a bit of maiden footage as well. Sadly my dad launched for me and only remembered to get the camera out during the last minute of the flight but I recorded enough to show how much of a big floater this plane is. The breeze never went above 3-4 mph, but you can tell still how much it gets kicked around by it. This is definitely more of an early morning flier.
The 020 power pack is more than enough power. I never went above 1/2 throttle for the entire flight except during the launch. It can easily climb vertically - I'm sure that will come in handy during the limited motor run event!
AUW with a 360 2s battery, and 1/8 ounce of tail weight. I found that's what it needed for a perfect CG. I expected it to want a more aft CG after all, as that's what tends to happen when you have lots of rearward sweep in your wings.
Have a bit of maiden footage as well. Sadly my dad launched for me and only remembered to get the camera out during the last minute of the flight but I recorded enough to show how much of a big floater this plane is. The breeze never went above 3-4 mph, but you can tell still how much it gets kicked around by it. This is definitely more of an early morning flier.
The 020 power pack is more than enough power. I never went above 1/2 throttle for the entire flight except during the launch. It can easily climb vertically - I'm sure that will come in handy during the limited motor run event!
