4 Metre Glider Scratch Build

[Wildthing]

Couple bandaids and a little glue and away you go , wish mine were that easy to fix

 

[Jackson T]

The crash was pretty horrific, and I was flying FPV, which made it even more traumatic! I guess I'm either good at building sturdy planes, or I don't crash hard enough . This is only my third EVER balsa build, so what looks like a 20 minute fix is still a head scratcher for me. It could be a lot worse though, so I'm grateful for that. Anyway, let's get into the repair!

I decided I needed to cut the nose cone off to get the broken firewall out and replace it, so that's where I started. The firewall broke in the centre, but I had pushed it back, which is why it looks intact.

Here's the new firewall in place and glued with PVA.

I have to straighten out the left fuselage side even though it's only a small bend, otherwise it won't follow the shape of the hatch. I think I'll probably glue a paddle pop stick in there or something.

 

[Jackson T]

That damage is nothing. You'll fix her up just fine. Your choice of colors was great. Transparent colors just seem to belong on a glider. I have a Great Planes Spirit glider kit that you may have inspired me to finally build even though I have no place to fly it.

Joe

Thanks! It looks great when it's up nice and high in a clear, blue sky with the transparent film. The Spirit looks like a great glider, you should build it! I built a balsa glider much like the Spirit, only 140cm wingspan compared to 200cm. I high started it at a footy field just fine, getting 50m of altitude or so with $10 worth of surgical tubing from ebay and some fishing line. You can probably fly these smaller gliders in most places you can fly parkflyers. Do you think you'd put a motor on yours, or leave it stock?

 

[TooJung2Die]

Is the fuselage side out of shape because it's cracked? Instead of a popsicle stick splint try CA glue in the crack. Bend the bent area back to normal shape and wick some thin CA glue into the area of the cracks. Don't use kicker so it soaks in deep. Hold the shape until the glue sets hard. If this works it'll be stronger than new.

I use CA to repair cracked balsa under covering film. Make a pin hole over the crack and put CA in the hole. It'll get sucked into the crack under the film.

 

[Jackson T]

Is the fuselage side out of shape because it's cracked? Instead of a popsicle stick splint try CA glue in the crack. Bend the bent area back to normal shape and wick some thin CA glue into the area of the cracks. Don't use kicker so it soaks in deep. Hold the shape until the glue sets hard. If this works it'll be stronger than new.

I use CA to repair cracked balsa under covering film. Make a pin hole over the crack and put CA in the hole. It'll get sucked into the crack under the film.

Yes and no. It's mostly just bent, but there's a buckle line as well. I'm not sure if it would work in this case, but I'll definitely keep it in mind for other damage areas. That pin hole method sounds very useful too, thanks for the tips!

 

[speedbirdted]

The crash was pretty horrific, and I was flying FPV, which made it even more traumatic! I guess I'm either good at building sturdy planes, or I don't crash hard enough . This is only my third EVER balsa build, so what looks like a 20 minute fix is still a head scratcher for me. It could be a lot worse though, so I'm grateful for that. Anyway, let's get into the repair!

I decided I needed to cut the nose cone off to get the broken firewall out and replace it, so that's where I started. The firewall broke in the centre, but I had pushed it back, which is why it looks intact. View attachment 157355

This is exactly why I like to build my firewalls to be strong enough to hold the motor and yank the plane through the air, but I also build them weak enough so that if there's a crash, it'll break. This might seem counterintuitive at first but cars have crumple zones for exactly the same reason, and on balsa airplanes it's even more important. Most of what's behind the firewall will be made of various sticks and sheets glued together, and repairing all those after your plane takes a nosedive is no fun, so you get around it by having the firewall absorb most of the force by breaking into pieces. The firewall is pretty much always the best location for a crumple zone (or the landing gear, but we have suspension for that, or the wings, but we have nylon bolts and rubber bands for that) because the motor/propeller is pretty much always going to be the first thing to hit the ground. It only works to a point though, and enough force will still break everything...

 

[Jackson T]

This is exactly why I like to build my firewalls to be strong enough to hold the motor and yank the plane through the air, but I also build them weak enough so that if there's a crash, it'll break. This might seem counterintuitive at first but cars have crumple zones for exactly the same reason, and on balsa airplanes it's even more important. Most of what's behind the firewall will be made of various sticks and sheets glued together, and repairing all those after your plane takes a nosedive is no fun, so you get around it by having the firewall absorb most of the force by breaking into pieces. The firewall is pretty much always the best location for a crumple zone (or the landing gear, but we have suspension for that, or the wings, but we have nylon bolts and rubber bands for that) because the motor/propeller is pretty much always going to be the first thing to hit the ground. It only works to a point though, and enough force will still break everything...

That's a good point, maybe that's why there's so litle damage considering how bad it was.

 

[speedbirdted]

That's a good point, maybe that's why there's so litle damage considering how bad it was.

exactly, if the firewall just transferred all the force to the nose and crumpled it to bits, you would be a lot less happy...

 

[Jackson T]

Here's how the wing's looking.

 

[TooJung2Die]

You'll be flying it again in no time.

 

[FoamyDM]

This looks generally minor repairs.

 

[Jackson T]

This looks generally minor repairs.

They look minor, but it's the spars, the shear webbing, and the sheeting at a wing joint that were looking at here. They're the main structural members at an increased stress point. I'm honestly a bit scared that the repairs will either be ugly and ruin the aerodynamics, or not be strong enough. I don't want either of those. We'll see how we go .

 

[Jackson T]

Finished the repairs! I decided to glue back in the original shear webs.

To access the front shear webs I needed to cut some of the leading edge sheeting off.

The wingtip rib was bent up, but I just glued it back into shape with CA instead of replacing it. The forces on it are next to nothing.

I had to repair a control horn as well. I CA'd a sliver of balsa in the crack and sanded it down.

I took it out for a re-maiden today, and it flew just like it used to. I found a few thermals, but had very limited success due to lack of removability.

I'm looking forward to more attempts though, and will probably build another smaller glider with ailerons for thermalling after I finish my PC 21.

 

[bracesport]

nice save Jackson - she is a beauty to be proud of - maybe call her 'theVerve'

 

[Jackson T]

nice save Jackson - she is a beauty to be proud of - maybe call her 'theVerve'

Thanks! Does the "Verve" mean anything in particular?

 

[TooJung2Die]

Does the "Verve" mean anything in particular?

I can hear my parents saying, "You have a dictionary. Look it up. " They refused to tell me. I hated that. Now we have Google.

 

[Jackson T]

I can hear my parents saying, "You have a dictionary. Look it up. " They refused to tell me. I hated that. Now we have Google.

I remember my parents saying that too .

 

[bracesport]

... the recently completed library possesses a verve and zest which conveys a dynamism that many of the more established universities might hanker after ...

 

[Jackson T]

When I first got my little boat, I lamented how the wind and currents in high country lakes (above 9,000 ft) would push and twist my boat, fouling the fishing lines. Now 10 years later, I wonder how I could get those lines into the nooks and crannies of shore structure (where the fish are) without those winds and currents. Even on lakes I have never been on before, I can 'see' those currents and anticipate them and I steer my boat into them to use them to my fishing advantage.

My point being, thermals are just like currents in the lake. It takes experience to learn how to use them and ride them. Every one is a unique opportunity and gaining this experience IS the fun (for me anyway).

Give it a year. By this time next year you should have some dings and some gnarly patches in that plane, but thermals will be your BFF.

I was re-reading my thread today, and saw your post again. Fast forward to now, and the dings are definitely there . While thermals were never my enemy, I was disappointed at first, thinking it couldn't thermal. But with practice, I've now had a good handful of successful thermal flights! In summer I had a few solid climbs, and even now (second half of autumn), I can sometimes maintain altitude. It is still a real challenge as the thermal cores are quite small lowdown and this thing doesn't turn on a dime, But I'm learning how to deal with it. The technique I've been using is to fly the circle passing through the middle of the core, then turn around for another pass through the core. Circling within the core the whole time seems to require quite a lot of bank, which takes a long time to get into without ailerons, and a long time to get out of.

I am getting better as I go, and I'm having a great time in the process! You must have been seeing into my future .

 

[cranialrectosis]

You must have been seeing into my future

I think the future is VERY bright for anyone who doesn't quit.

"All the gods, all the heavens all the hells are within you."-Campbell

I like that we have such un-common people here!

IMO trying to circle inside a thermal is a trick for falcons not hawks. You have an eagle or hawk wing. Not a falcon wing.

Fly between thermals if you can. Instead of flying figure 8s with the thermal in the middle, fly with two thermals, one on each end of the 8. Fly between the thermals and make your slow turns in the thermals. Do your aerobatics in the middle with the thermals on each end.

That said, ailerons are freaking awesome!