repair question
04-13-2011 | 05:50 PM
#1
Thread Starter
Senior Member
repair question
I finally got around to repairing my stik, that lost it's wings in flight (they don't fly very well without wings)
I cut the fuselage off where it was bad and have built a new front half for it. I only have the 1/4 balsa sides and about 1 square inch of plywood holding the front half with the back half. It feels strong, but I don't fully trust it. I was thinking about putting some light fiberglass cloth on the sides to help reinforce it. I have a few questions.
1. is that a dumb idea to use some fiberglass to strengthen the bond.
2. would you use polyurethane or epoxy
3. I was going to use .75oz weight stuff (the really light stuff) is that enough?
4 would you do anything different or do you have any suggestions?
Thanks
I cut the fuselage off where it was bad and have built a new front half for it. I only have the 1/4 balsa sides and about 1 square inch of plywood holding the front half with the back half. It feels strong, but I don't fully trust it. I was thinking about putting some light fiberglass cloth on the sides to help reinforce it. I have a few questions.
1. is that a dumb idea to use some fiberglass to strengthen the bond.
2. would you use polyurethane or epoxy
3. I was going to use .75oz weight stuff (the really light stuff) is that enough?
4 would you do anything different or do you have any suggestions?
Thanks
04-13-2011 | 06:02 PM
#2
RE: repair question
Fiberglass cloth and epoxy is a good, strong repair but adds a lot of weight if you go overboard. It can alsobe a pain to sand flush. Plan ahead and laywaxed paper over the exterior epoxy for a smooth &finished cure. In a lot of repairs Ionly use epoxy at the stress points and use light balsa plyor popsicle sticks and Titebond II for the rest.
04-13-2011 | 06:06 PM
#3
Thread Starter
Senior Member
RE: repair question
Thanks, the good thing that I have going for me is it is a stik, it is my beater plane, a fun plane to fly, but I don't care if it has a war wound or two and I think it can handle a little more weight 
I tend to fly planes better if I don't worry about crashing them )))))))))))))
I tend to fly planes better if I don't worry about crashing them )))))))))))))
04-13-2011 | 06:20 PM
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From: GraftonNew South Wales, AUSTRALIA
RE: repair question
As reinforcement I would use a much heavier cloth than 0.75, especially if you can handle a little extra weight.
Just my $0.02
Terry
Just my $0.02
Terry
04-13-2011 | 07:55 PM
#6
RE: repair question
It looks like you have some overlap on both sides, so there should be enough material there. The only issue is that you're relying on the balsa on the outside for strength, so I'd put a 1 inch wide ply doubler on the inside so you have a continuous plywood structure. If you woodpecker it and use slow cure epoxy it'll be the strongest part of the whole airplane after that.
04-14-2011 | 05:59 AM
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From: Fulton,
NY
RE: repair question
If you extend the ply doubler that's already there so that it goes the whole length of the wing saddle, it'll take another crash to make it come apart, but IMHO, it looks good the way it is.
04-14-2011 | 06:28 AM
#8
My Feedback: (1)
RE: repair question
Ya, done pretty good! cover it and start flying it. Don,t make the mistake of getting into the mindset that you have reinforce to point that it will survive another single point landing without a wing.
Next time on a similar repair don't do a butt joint of the sides like that but rather a scarf joint, the sides cut and joined with an angle preferrably around forty five degress. When you use thicker sides on a box fuse like that you can if you like forego the ply full length doublers.
If you really want to do a bit more rather than fiberglas just epoxy 1/32 ply joint doublers on the inside of the butt joint on the balsa only not where the ply is and these little doublers only need to be about a half inch wide. Just stripes over the balsa butt joint.
John
Next time on a similar repair don't do a butt joint of the sides like that but rather a scarf joint, the sides cut and joined with an angle preferrably around forty five degress. When you use thicker sides on a box fuse like that you can if you like forego the ply full length doublers.
If you really want to do a bit more rather than fiberglas just epoxy 1/32 ply joint doublers on the inside of the butt joint on the balsa only not where the ply is and these little doublers only need to be about a half inch wide. Just stripes over the balsa butt joint.
John
04-14-2011 | 10:26 AM
#9
My Feedback: (-1)
RE: repair question
Glassing to reinforce isn't all that good, as John pointed out, using some thin ply is much stronger. In the photos the first shot in my very old Kaos back in 04 after the fuel soaked wood let go. There was no outside wood left at all up front that wasn't oil soaked so I used some very thick balsa on the outside, it was I think 1/4 inch?? I didn't care about how it looked. At this point I had a YS 1.10 installed, I used a lot of different engines over the years in that plane. I used 1/32 ply on the inside as a doubler. Then last year I gave it the fourth covering job and was using an OS .91FS for power. Late last year I finally lost this old plane due to lack of altitude and an engine problem. The nose section of the plane didn't break off, well, it did but not in my repaired section anyway. After flying for about two decades it finally found it's expiration date.[&o]
04-14-2011 | 12:09 PM
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From: Rockwall TX
RE: repair question
Gray,
Are these planes designed by you? Are they scratch built or KiT, whatever they are, they are really nice and cool looking planes, I bet the fly in the air like a bat outta hell? They look pretty fast and sporty. Awesome planes. If you don't need another one you may send it to me lol
Mody
Are these planes designed by you? Are they scratch built or KiT, whatever they are, they are really nice and cool looking planes, I bet the fly in the air like a bat outta hell? They look pretty fast and sporty. Awesome planes. If you don't need another one you may send it to me lol
Mody
04-14-2011 | 12:44 PM
#11
Thread Starter
Senior Member
RE: repair question
Thanks guys, I will add some plywood on the outside. I should have done a few things different, I made the new plywood on the inside, but I should have made it a little longs, I was not really thinking. I cut it there, mainly because that is about where it broke and I did not want to redo the servos (lazy) It is basically built the same as when I got it, I just want to add a little more. I am worried about the wooden mounts breaking off again (all 4 broke off with the wing, and the wing just floated down gently, while I was trying to use the elevator to bring the wingless body up from it's dive )) )
Mody, I believe most of the planes that Greybeard (Gene) has are Kaos, or more "vingtage" pattern planes 1 might be a birdie.
Mody, I believe most of the planes that Greybeard (Gene) has are Kaos, or more "vingtage" pattern planes 1 might be a birdie.
04-14-2011 | 01:11 PM
#12
My Feedback: (-1)
RE: repair question
ORIGINAL: armody
Gray,
Are these planes designed by you? Are they scratch built or KiT, whatever they are, they are really nice and cool looking planes, I bet the fly in the air like a bat outta hell? They look pretty fast and sporty. Awesome planes. If you don't need another one you may send it to me lol
Mody
Gray,
Are these planes designed by you? Are they scratch built or KiT, whatever they are, they are really nice and cool looking planes, I bet the fly in the air like a bat outta hell? They look pretty fast and sporty. Awesome planes. If you don't need another one you may send it to me lol
Mody
Both planes are a design by Joe Bridi and kit built. Both kits can be bough from Blue Jay and are very cheap kits. These are just old class C pattern planes. The DB really did fly better then the Kaos, just didn't last very long. The kits are old school and you get printed out instructions without any photos. They also don't tell you to cut a 6 inch piece from a 24 inch piece, they are designed for people that know how to build a kit the old way, you just need to think while building. These are what we call builders kits. They are both designed to use fixed gear or retracks. The Kaos at one point had retracks but I removed them and wint with fixed at some point. These are the perfect airplane designs, all the old pattern planes are great. You can read about them in the classic pattern forum. Take a little computer trip to the Blue Jay site. They are also sold through Bridi.
Gene
04-14-2011 | 02:49 PM
#13
RE: repair question
ORIGINAL: Minnreefer
......................, while I was trying to use the elevator to bring the wingless body up from it's dive )) )
......................, while I was trying to use the elevator to bring the wingless body up from it's dive )) )
04-14-2011 | 02:52 PM
#14
RE: repair question
Minnreefer - the Bridi designs sold by Blue Jay are kits as they were sold "back in the day". Pictures? Who needs stinkin' pictures. Very satisfying build project. Check out the various build threads - a lot of good information.
04-14-2011 | 03:10 PM
#15
My Feedback: (-1)
RE: repair question
I made templates of every part of the Yellow Birdy but just buying a new kit would be the easy way to go. For a taste over $100.00 you get everything and don't have to do all the thinking required to buy your wood. I would build another Dirty Birdy but I Have a couple pattern planes on hand so maybe in my future?? There are just so many nice planes, I hate to build the same plane twice. The Kazmirski Simla kit will be out sometime in June and it looks to be a great build too. There is a story and build article in Model Aviation March Magazine with all info.
04-14-2011 | 04:46 PM
#16
Thread Starter
Senior Member
RE: repair question
ORIGINAL: SeamusG
Minnreefer - the Bridi designs sold by Blue Jay are kits as they were sold ''back in the day''. Pictures? Who needs stinkin' pictures. Very satisfying build project. Check out the various build threads - a lot of good information.
Minnreefer - the Bridi designs sold by Blue Jay are kits as they were sold ''back in the day''. Pictures? Who needs stinkin' pictures. Very satisfying build project. Check out the various build threads - a lot of good information.
I know, I want to build one. I have yet to build a kit, since the last one that I built when I was 16 (a pt 20 I think?) I just need to get started, but I am just about done with my other repair projects and have started to clean my workshop area. I would love to build a 4*40 kit, but I just bought a built venture 60 with an engine and full remote for $140. Maybe I will build a smoothie or my hog bipe.
Gene, I saw that article about the Simla also, it looks very cool, I like those pattern planes, they do fly smooth.
04-14-2011 | 05:50 PM
#18
My Feedback: (-1)
RE: repair question
ORIGINAL: rglgatortail
this is what I'm wanting to get here in another month http://www.bridiairplanes.com/hangar/killerchaos60.html
this is what I'm wanting to get here in another month http://www.bridiairplanes.com/hangar/killerchaos60.html
04-14-2011 | 05:53 PM
#19
RE: repair question
Hey Robert - good choice. Here's my build thread for the Killer Chaos 60 (may it RIP) 
Too bad I sold my spare fuse pieces (sides, doublers & formers) before it did a belly flop.
Too bad I sold my spare fuse pieces (sides, doublers & formers) before it did a belly flop.
04-14-2011 | 06:06 PM
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From: Stone Ridge,
NY
RE: repair question
ORIGINAL: Minnreefer
Thanks guys, I will add some plywood on the outside. I should have done a few things different, I made the new plywood on the inside, but I should have made it a little longs, I was not really thinking. I cut it there, mainly because that is about where it broke and I did not want to redo the servos (lazy) It is basically built the same as when I got it, I just want to add a little more. I am worried about the wooden mounts breaking off again (all 4 broke off with the wing, and the wing just floated down gently, while I was trying to use the elevator to bring the wingless body up from it's dive )) )
Mody, I believe most of the planes that Greybeard (Gene) has are Kaos, or more ''vingtage'' pattern planes 1 might be a birdie.
Thanks guys, I will add some plywood on the outside. I should have done a few things different, I made the new plywood on the inside, but I should have made it a little longs, I was not really thinking. I cut it there, mainly because that is about where it broke and I did not want to redo the servos (lazy) It is basically built the same as when I got it, I just want to add a little more. I am worried about the wooden mounts breaking off again (all 4 broke off with the wing, and the wing just floated down gently, while I was trying to use the elevator to bring the wingless body up from it's dive )) )
Mody, I believe most of the planes that Greybeard (Gene) has are Kaos, or more ''vingtage'' pattern planes 1 might be a birdie.
Your repair looks like it should be strong enough as is but I also agree with the thin plywood or even carbon fiber tape to reinforce the joint. We used to take a piece of 1/4" ply about 1/2" wide x 3" long and glue a little handle to it. Then on the bottom opposite the handle, glue a strip of 60 or 80 grit sandpaper about 1/4" to 3/8" wide by the length of the base plus a little overlap to secure the sandpaper. Now, using a straight edge, run the little block along the straight edge to sand an indent in the balsa side until the base of the sander contacts the outer surface of the sheeting. You'll have an indent that is just the thickness of the sandpaper and at 60 to 80 grit, should be somewhere around 1/32" if I'm not too far off. Mix up some 15 Minute epoxy and glue your plywood strengthener in the groove and you should be all set. Wipe off any excess with a little alcohol on a paper towel before the epoxy totally sets.
Hope this helps you out a bit.
04-14-2011 | 06:11 PM
#21
My Feedback: (-1)
RE: repair question
ORIGINAL: John Sohm
Am I to understand that the wing just tore off the plane and floated down and that's what caused the crash and resulting damage? Because if that's the case, I think I would be more concerned with the method you used to attach the mounting blocks to start with. Those blocks should always be epoxied in place. Don't use CA because it has one of the weakest bonds of any adhesive in the shear direction. Wood working glue aka Aliphatic glue is strong but make sure there's a good fillet around the joint but I always use epoxy.
Your repair looks like it should be strong enough as is but I also agree with the thin plywood or even carbon fiber tape to reinforce the joint. We used to take a piece of 1/4'' ply about 1/2'' wide x 3'' long and glue a little handle to it. Then on the bottom opposite the handle, glue a strip of 60 or 80 grit sandpaper about 1/4'' to 3/8'' wide by the length of the base plus a little overlap to secure the sandpaper. Now, using a straight edge, run the little block along the straight edge to sand an indent in the balsa side until the base of the sander contacts the outer surface of the sheeting. You'll have an indent that is just the thickness of the sandpaper and at 60 to 80 grit, should be somewhere around 1/32'' if I'm not too far off. Mix up some 15 Minute epoxy and glue your plywood strengthener in the groove and you should be all set. Wipe off any excess with a little alcohol on a paper towel before the epoxy totally sets.
Hope this helps you out a bit.
ORIGINAL: Minnreefer
Thanks guys, I will add some plywood on the outside. I should have done a few things different, I made the new plywood on the inside, but I should have made it a little longs, I was not really thinking. I cut it there, mainly because that is about where it broke and I did not want to redo the servos (lazy) It is basically built the same as when I got it, I just want to add a little more. I am worried about the wooden mounts breaking off again (all 4 broke off with the wing, and the wing just floated down gently, while I was trying to use the elevator to bring the wingless body up from it's dive )) )
Mody, I believe most of the planes that Greybeard (Gene) has are Kaos, or more ''vingtage'' pattern planes 1 might be a birdie.
Thanks guys, I will add some plywood on the outside. I should have done a few things different, I made the new plywood on the inside, but I should have made it a little longs, I was not really thinking. I cut it there, mainly because that is about where it broke and I did not want to redo the servos (lazy) It is basically built the same as when I got it, I just want to add a little more. I am worried about the wooden mounts breaking off again (all 4 broke off with the wing, and the wing just floated down gently, while I was trying to use the elevator to bring the wingless body up from it's dive )) )
Mody, I believe most of the planes that Greybeard (Gene) has are Kaos, or more ''vingtage'' pattern planes 1 might be a birdie.
Your repair looks like it should be strong enough as is but I also agree with the thin plywood or even carbon fiber tape to reinforce the joint. We used to take a piece of 1/4'' ply about 1/2'' wide x 3'' long and glue a little handle to it. Then on the bottom opposite the handle, glue a strip of 60 or 80 grit sandpaper about 1/4'' to 3/8'' wide by the length of the base plus a little overlap to secure the sandpaper. Now, using a straight edge, run the little block along the straight edge to sand an indent in the balsa side until the base of the sander contacts the outer surface of the sheeting. You'll have an indent that is just the thickness of the sandpaper and at 60 to 80 grit, should be somewhere around 1/32'' if I'm not too far off. Mix up some 15 Minute epoxy and glue your plywood strengthener in the groove and you should be all set. Wipe off any excess with a little alcohol on a paper towel before the epoxy totally sets.
Hope this helps you out a bit.
04-14-2011 | 07:17 PM
#22
Thread Starter
Senior Member
RE: repair question
I got the plane mostly built as a kit build, (someone else built it) I did not install the mounting blocks, but that still worries me. When I installed new ones I epoxied them well, but I still worry about that for strength.
I am going to use 1/32 ply to help make the joint a bit stronger.
Thanks guys, I really am not that worried about building planes, I just need to get some extra time and confidence.
I am going to use 1/32 ply to help make the joint a bit stronger.
Thanks guys, I really am not that worried about building planes, I just need to get some extra time and confidence.
04-14-2011 | 07:37 PM
#24
RE: repair question
It looks like the fuse wing mounts are made of 1/4" plywood with 1/4x20 holes tapped. I can't tell if there is an tri-stock glued to the bottom side of the mounts and the fuse. If NOT - add 3/4" (at least 1/2") tri-stock. It should help to connect the mounts to both the fuse sides AND the former at the rear of the wing bay. Then just drill undersized holes thru the existing mounting holes and tap them to match the original. Use 30-min epoxy for the glue.
04-14-2011 | 07:55 PM
#25
Thread Starter
Senior Member
RE: repair question
ORIGINAL: SeamusG
It looks like the fuse wing mounts are made of 1/4'' plywood with 1/4x20 holes tapped. I can't tell if there is an tri-stock glued to the bottom side of the mounts and the fuse. If NOT - add 3/4'' (at least 1/2'') tri-stock. It should help to connect the mounts to both the fuse sides AND the former at the rear of the wing bay. Then just drill undersized holes thru the existing mounting holes and tap them to match the original. Use 30-min epoxy for the glue.
It looks like the fuse wing mounts are made of 1/4'' plywood with 1/4x20 holes tapped. I can't tell if there is an tri-stock glued to the bottom side of the mounts and the fuse. If NOT - add 3/4'' (at least 1/2'') tri-stock. It should help to connect the mounts to both the fuse sides AND the former at the rear of the wing bay. Then just drill undersized holes thru the existing mounting holes and tap them to match the original. Use 30-min epoxy for the glue.
