Bridi UFO Build (all wood)
03-10-2006, 09:50 PM
#3
RE: Bridi UFO Build (all wood)
Thanks 8178. I"ve tried several methods of cutting parts over the years and using Super 77 to attach paper patterns directly to the balsa is the easiest and most accurate for me. A bit of thinner brushed on the paper instantly releases it from the wood.
I'm going to laminate the 1/2" x 1" LE from two 1/4" x 1" strips. This will be a bit stronger and a bit more warp resistant. The UFO wing is very minimal in its construction. There are no shear webs and no dihedral braces, and the spars are balsa, not spruce. I will certainly strengthen the area that supports the retract mounting plate; no ply doublers are shown on the plan (they're shown for the fixed gear blocks only). One idea I'm thinking about is to go ahead and sheet the entire wing and then glass it, which makes sense to me. It would probably create a nicer finish, too.
Here's a section of the plans. Note the instructions about joining the wing halves.
I'm going to laminate the 1/2" x 1" LE from two 1/4" x 1" strips. This will be a bit stronger and a bit more warp resistant. The UFO wing is very minimal in its construction. There are no shear webs and no dihedral braces, and the spars are balsa, not spruce. I will certainly strengthen the area that supports the retract mounting plate; no ply doublers are shown on the plan (they're shown for the fixed gear blocks only). One idea I'm thinking about is to go ahead and sheet the entire wing and then glass it, which makes sense to me. It would probably create a nicer finish, too.
Here's a section of the plans. Note the instructions about joining the wing halves.
03-11-2006, 08:18 AM
#4
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RE: Bridi UFO Build (all wood)
If you are going to go the sheeting route.... here is something to think about. Dynamic Balsa offers foam wing cores along with the cores for the stab.
http://dbalsa.com/
Click on "foam wings". In the right hand colum, click on "replacement wings". Click on the letter "U" and the wing/stab cores are the first ones on the list.
http://dbalsa.com/
Click on "foam wings". In the right hand colum, click on "replacement wings". Click on the letter "U" and the wing/stab cores are the first ones on the list.
03-11-2006, 10:07 AM
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RE: Bridi UFO Build (all wood)
ORIGINAL: impactiq
If you are going to go the sheeting route.... here is something to think about. Dynamic Balsa offers foam wing cores along with the cores for the stab.
http://dbalsa.com/
Click on "foam wings". In the right hand colum, click on "replacement wings". Click on the letter "U" and the wing/stab cores are the first ones on the list.
If you are going to go the sheeting route.... here is something to think about. Dynamic Balsa offers foam wing cores along with the cores for the stab.
http://dbalsa.com/
Click on "foam wings". In the right hand colum, click on "replacement wings". Click on the letter "U" and the wing/stab cores are the first ones on the list.
03-11-2006, 11:27 AM
#6
RE: Bridi UFO Build (all wood)
Thanks for the tip impactiq. Wings are my favorite part of the model to build. I really love cutting out ribs and all that.
SteveW, I think that would be a great comparison build with this one that I'm doing. It would be interesting to see how the weights compare. Who made a glass fuse for the UFO?
Yummy, freshly cut ribs!
SteveW, I think that would be a great comparison build with this one that I'm doing. It would be interesting to see how the weights compare. Who made a glass fuse for the UFO?
Yummy, freshly cut ribs!
03-12-2006, 09:15 PM
#8
RE: Bridi UFO Build (all wood)
I've set up the jig that the wing will be built on. It's nothing fancy, it just ensures that the wing is straight. The centerline of the ribs will be equidistant from the board so that the ribs are perpendicular to the board and both spars converge towards the tip at the same angles to the ribs. I did this because the UFO wing has dihedral. With a Kaos I would set it up so the top spar is parallel to the board and the ribs perpendicular to it and the board, and let the bottom spar angle upward since it's "dihedral" comes from the thickness taper. I guess it doesn't really matter, but hey, it's fun to work all this stuff out.
I haven't glued anything yet. I'm using two slotted gauges to make sure the ribs are square and lined up over the plans since they are up off of the board. Come to think of it, this is the first swept-back R/C wing I've ever built. It's already looking pretty cool.
I haven't glued anything yet. I'm using two slotted gauges to make sure the ribs are square and lined up over the plans since they are up off of the board. Come to think of it, this is the first swept-back R/C wing I've ever built. It's already looking pretty cool.
03-13-2006, 10:30 PM
#9
RE: Bridi UFO Build (all wood)
I didn't do too much tonight. I'm working on one of the wing panels and got one side sheeted. Next I'll install ply rib doublers and cross braces for the retract mounting plates.
I'm thinking I'll put a servo in each wing. It's just so much easier than making torque rods and installing them in the wing. Although the design is straightforward, there's a lot more work to this one than with a Kaos.
I'm thinking I'll put a servo in each wing. It's just so much easier than making torque rods and installing them in the wing. Although the design is straightforward, there's a lot more work to this one than with a Kaos.
03-14-2006, 11:06 PM
#14
RE: Bridi UFO Build (all wood)
Well, at least the arfers from the woodchucks (see pic).
The LE has been planed and sanded. Time to start the othe wing panel.
The LE has been planed and sanded. Time to start the othe wing panel.
Is it wrong for a grown man to get excited by a built up wing??
I just love these build threads.Mark
03-15-2006, 07:11 AM
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RE: Bridi UFO Build (all wood)
Looks great raineday, and there is nothing like all the shavings from a sharp razor plane. I swear my cat loves the balsa more than katnip. These builds have me pulling out the curare plans I have, but need to finish other projects first, so i will watch and follow these here with great jealousy.
03-17-2006, 02:36 AM
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RE: Bridi UFO Build (all wood)
Very cool to see your build thread for the Joe Bridi UFO. This is one of my favorite old pattern designs and I love the all wood construction! I still have buried somewhere my old September 1977 RCM magazine with the original construction article. Did you buy your plans from RCM? Is the canopy shown on the plan carved from balsa or plastic?
03-17-2006, 03:50 AM
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RE: Bridi UFO Build (all wood)
I recall it is carved from plastic
Drawings show text: "Dirty Bridy" canopy available from RCM... (it is approx 2" shorter)
Hope this helps... -Jari-
Drawings show text: "Dirty Bridy" canopy available from RCM... (it is approx 2" shorter)
Hope this helps... -Jari-
03-17-2006, 10:00 AM
#22
RE: Bridi UFO Build (all wood)
Thanks everyone for the compliments!
McLeodAviation, if you happen to unearth that construction article, I'd greatly appreciate a copy! And yes, I'm building from the RCM plans.
I haven't thought too much about the canopy yet, other than to look at the one Wing Mfg. sells. Someone (?) said in another thread that the pinched area at the base of the canopy added an aerodynamic advantage of some sort. I suppose I could boil a vacuform canopy and press the sides onto a dowell. It would be tricky to do without distorting it too much. A carved balsa canopy is maybe an easier route since I'm going to glass and paint the fuselage anyway.
I'm getting ready to shape and carve the wingtips. I'll post more pics tonight of that stage.
McLeodAviation, if you happen to unearth that construction article, I'd greatly appreciate a copy! And yes, I'm building from the RCM plans.
I haven't thought too much about the canopy yet, other than to look at the one Wing Mfg. sells. Someone (?) said in another thread that the pinched area at the base of the canopy added an aerodynamic advantage of some sort. I suppose I could boil a vacuform canopy and press the sides onto a dowell. It would be tricky to do without distorting it too much. A carved balsa canopy is maybe an easier route since I'm going to glass and paint the fuselage anyway.
I'm getting ready to shape and carve the wingtips. I'll post more pics tonight of that stage.
03-17-2006, 11:11 PM
#24
RE: Bridi UFO Build (all wood)
Thanks, Paternguy. Yeah, the Great Planes canopy is 17 3/4" and the Wing Mfg. is 19 1/2" long. The plans actually measure a bit over 22" but the Wing canopy looks like the one to get.
I've finished the wing panels except for the center sheeting and the gear mounts. In 8178's Cold Duck build thread he used a ply tongue instead of dowels for the wing attachment. I was really impressed with that method, so I'm going to borrow it for this model. In fact, I've been going back and reading his build threads a lot since there are so many cool techniques to benefit from. I know the plans show a single aileron servo and torque rods, but I'm going to use two wing servos at the risk of untrue to the original design. Here's my take on it: two servos are a lot easier to use and it's that much less space taken up in the fuselage (if I go with mechanical retracts I'll have a servo in the wing root anyway). Also, in the 70s it was probably a lot easier to sell designs that only needed four servos as opposed to five. If servos had cost the equivalent of today's $15 to $20 each back then, I'm sure more planes would have been designed for two aileron servos.
Here're some pics. I'll start the stab tomorrow.
I've finished the wing panels except for the center sheeting and the gear mounts. In 8178's Cold Duck build thread he used a ply tongue instead of dowels for the wing attachment. I was really impressed with that method, so I'm going to borrow it for this model. In fact, I've been going back and reading his build threads a lot since there are so many cool techniques to benefit from. I know the plans show a single aileron servo and torque rods, but I'm going to use two wing servos at the risk of untrue to the original design. Here's my take on it: two servos are a lot easier to use and it's that much less space taken up in the fuselage (if I go with mechanical retracts I'll have a servo in the wing root anyway). Also, in the 70s it was probably a lot easier to sell designs that only needed four servos as opposed to five. If servos had cost the equivalent of today's $15 to $20 each back then, I'm sure more planes would have been designed for two aileron servos.
Here're some pics. I'll start the stab tomorrow.
