kacknor
Build another!
That wing folding problem has occurred on both of my Tiny Trainers and a Bushwacker. I now add longitudinal stinger support (Popsicle sticks)
on the underside of the wing of any build using rubber bands. JD
Schoolgirl biplane DT foam board maiden flight
- Thread starter TooJung2Die
- Start date
That wing folding problem has occurred on both of my Tiny Trainers and a Bushwacker. I now add longitudinal stinger support (Popsicle sticks)
on the underside of the wing of any build using rubber bands. JD
BobK
Banned
I agree about removing paper, this has been kind of a test/learning project..cool airplane so I wanted it to look it so I left the paper on since I didn't know what to expect. Surprisingly before adding the wrap and with the huge holes it really does not feel much if any less strong as before, even when twisting the wing by the ends. After covering I feel the wrap has added a large amount of strength and it would be interesting to do some load tests. It feels like a normally covered balsa wing for weight and strength.
I think a wing with inside paper removed, covered with wrap and no holes would be the strongest lightest way to go here. I am afraid if all paper is removed the wrap shrinks enough to crush at least the edges..if I didn't leave any paper here I am certain my cut-outs would crush.
I would say the strength of the wrap compared to different covering films would be somewhere between regular Monokote/Ultracote and lighter films like Solite. The bad part is I am having a tough time finding other colors, DT only has transparent blue and red, and also a clear (which can be painted if weight isn't a concern). I haven't looked terribly hard but the only other plastic (cellophane) type gift wrap I found was Hello Kitty..which after much debate I passed on.
I think I will focus on getting it in the air at this point and then try some different things with the foam and wrap.
I think a wing with inside paper removed, covered with wrap and no holes would be the strongest lightest way to go here. I am afraid if all paper is removed the wrap shrinks enough to crush at least the edges..if I didn't leave any paper here I am certain my cut-outs would crush.
I would say the strength of the wrap compared to different covering films would be somewhere between regular Monokote/Ultracote and lighter films like Solite. The bad part is I am having a tough time finding other colors, DT only has transparent blue and red, and also a clear (which can be painted if weight isn't a concern). I haven't looked terribly hard but the only other plastic (cellophane) type gift wrap I found was Hello Kitty..which after much debate I passed on
.I think I will focus on getting it in the air at this point and then try some different things with the foam and wrap.
BobK
Banned
That wing folding problem has occurred on both of my Tiny Trainers and a Bushwacker. I now add longitudinal stinger support (Popsicle sticks)
JD
It did it right away on the first flight of my Bushwacker while it was in the air, I did a loop and the plane wanted to keep doing loops by itself.
I run full length popcycle sticks pushed/glued right into the foam.
kacknor
Build another!
It did it right away on the first flight of my Bushwacker while it was in the air, I did a loop and the plane wanted to keep doing loops by itself.
Oh yeah. Interesting flight from the time the wing bends until getting it down. Same thing occurred to me. That plane taught me a lot. How to land tail heavy, how to land with the wing 'flapping' against the fuse in flight, and to land with that bending issue when the extra rubber bands added to stop the flapping bent the wing.
The one amazing thing is I still have it, and it's only a RX and pod away from flight status.
JD
Last edited:
BobK
Banned
The Bushwacker is definitely an all around bash it up airplane, mine is still going strong even after landing it on a powerline where it hung for three days
I have been looking for a flyer though, and Jon's job on his Schoolgirl here shows it is one. I just hope the fact that mine is much bigger doesn't ruin that part of it but I am pretty confident it won't. Every time I start slacking he posts a video teasing me so I have to keep working on mine.
I have been looking for a flyer though, and Jon's job on his Schoolgirl here shows it is one. I just hope the fact that mine is much bigger doesn't ruin that part of it but I am pretty confident it won't. Every time I start slacking he posts a video teasing me so I have to keep working on mine.
TooJung2Die
Master member
We'll see if we can mojo some calm, warmer weather for your test flight. Going larger rarely results in a worse flying design unless you go ridiculously large. Going smaller seems to be where the problems arise. That's what I've read, just saying, I'm no expert. The Schoolgirl is a flyer. The way I like to fly it is like flying a kite without the string. No stress.
So get to it, or I'll have to video what happens when a noobie pilot attempts a flat spin.
Jon
TooJung2Die
Master member
I actually tried to flat spin the Schoolgirl yesterday. I never got it into flat spin but I had her doing all sorts of flip-flops, stalls and sometimes something that looked like a hammerhead or wing-over. All that happened at nice safe altitude so even if I was recording it would have been just a speck. Sometimes it's fun to throw the controls around just to see what happens. I'm building a new fuselage for the Ranger 30 tonight. It's a sporty little airplane and it's small size makes me bolder when flying it. I've lost count of how many times I've repaired or rebuilt the Ranger. Maybe that one will flat spin.
I'll keep my fingers crossed your weather cooperates.
Jon
I'll keep my fingers crossed your weather cooperates.
Jon
TooJung2Die
Master member
I weighed the Schoolgirl with a 1000mAh 3s battery and she's 470 grams. The landing gear alone weigh 27 grams. I think you would have to do some crazy weight saving to keep it under 250 grams. You might have to make it a top wing monoplane. According to Willard it flies great that way but would lose the biplane cool factor.
Jon
BobK
Banned
Any idea how much HK 3mm foam weighs per sheet?
No LG probably, and I wonder if going 80% you could get by with leaving out some pieces..fuselage bottom maybe to start? I don't know if it would help with weight but I have cut holes and used regular food wrap (Cling wrap) as a covering material. Could the wings be made as just a single sheet with a light spar leaving out the bottom?
I'm no expert at weight savings, my big Schoolgirl is sitting at 1060g RTF which I guess isn't terrible for its size.
I keep looking at mine with the bottom wing off and tall LG it seriously sits like a STOL airplane, I think what I am going to do is build a "cap" for the bottom wing saddle of the fuse and make a longer top wing with flaps. A quick wing change and I have a dual purpose airplane.
TooJung2Die
Master member
Cool, keep us posted I would like to see how it goes
Yes, a mini ultralight Schoolgirl would be very cool.
Just weighed some. Came up with 734 grams for a stack of 20. So 36.7 grams per sheet and .0676 grams per square inch.
I've been using the 3mm mainly for wings and tails wrapping with the 2.75mil Oracal vinyl sign stuff ( single sided for wings, double sided for tails ). Definately makes the leading edge much sharper. It's a bit too flimsy for my tasts for use as the fuselage. I built a mini mustang with it but haven't maiden yet. Fully assembled FT min Mustang wing covered, hot glue, aileron emax 9051 servos installed, and 6" Y harness comes in at 51grams.
Nice bonus is take 42" plane plans and shrink down to 60% for mighty mini size and you don't have to mess with the A/B fold or tabs sizes in the plans becuase it stays proportional. I've got a couple on the table half complete.
Nice bonus is take 42" plane plans and shrink down to 60% for mighty mini size and you don't have to mess with the A/B fold or tabs sizes in the plans becuase it stays proportional. I've got a couple on the table half complete.
Last edited:
BobK
Banned
Nice, I tried cheating since I don't have any to weigh by adding a case to the shopping cart on the website and it said 1628g (81.4g/sheet) for shipping weight which I figured included packaging so my idea wasn't even close.
BobK
Banned
I have an over abundance of this funky bright red/orange vinyl that I have been trying to use up so I threw down some quick color, it really isn't what I had in mind but until I see if she flies it will work..I figured it was at least nice and bright . Nice thing about vinyl is when I decide to do something different I can just peel it off and throw it away.
The battery will have to sit right above the bottom wing to get the balance right, I did build a battery shelf and a hatch into the bottom behind the firewall but it is way too far forward, the piece in front of the windshield is a friction-fit hatch door, the ESC lives there. Still looks like a flying day tomorrow, funny how I get nervous over a plane that I have about $5 of materials in
. Nice thing about vinyl is when I decide to do something different I can just peel it off and throw it away.The battery will have to sit right above the bottom wing to get the balance right, I did build a battery shelf and a hatch into the bottom behind the firewall but it is way too far forward, the piece in front of the windshield is a friction-fit hatch door, the ESC lives there. Still looks like a flying day tomorrow, funny how I get nervous over a plane that I have about $5 of materials in
TooJung2Die
Master member
Wow, she looks awesome, Bob. You did good with the vinyl trim. Not too much because you want to see the cutout work through the covering. It will look cool with the sun shining through the wings. You get sun in MN right?
Please take a photo of the bottom. I'd like the see the details on the landing gear and bottom hatch. I'm always looking for a better way to make landing gear since that part of the airplane takes the most constant abuse. Landing gear is a must here in the desert where large grassy areas are uncommon. I get maiden flight jitters too as evidenced by the Schoolgirl maiden flight video. The first few flights of the early version Ranger did not go well and are still fresh in my mind. Glad I got that design worked out. I'm going to fly the Ranger today with a new, improved fuselage and landing gear design.
The bottom wing of the Schoolgirl is right where you would want to hold the airplane for a hand launch. It makes hand launching awkward so I've been using my least favorite method of take-off, rise off ground. With all that wing she takes to the air quick.
Please take a photo of the bottom. I'd like the see the details on the landing gear and bottom hatch. I'm always looking for a better way to make landing gear since that part of the airplane takes the most constant abuse. Landing gear is a must here in the desert where large grassy areas are uncommon. I get maiden flight jitters too as evidenced by the Schoolgirl maiden flight video.
The first few flights of the early version Ranger did not go well and are still fresh in my mind. Glad I got that design worked out. I'm going to fly the Ranger today with a new, improved fuselage and landing gear design.The bottom wing of the Schoolgirl is right where you would want to hold the airplane for a hand launch. It makes hand launching awkward so I've been using my least favorite method of take-off, rise off ground. With all that wing she takes to the air quick.
