Great Planes RV-4 Build w/ pictures
03-18-2013, 11:55 AM
#26
RE: Great Planes RV-4 Build w/ pictures
The wing... since some have asked about it.
the wing builds in a jig that is part of the construction. the ribs and main spar and there is a trailing edge spar all interlock together to give you a "correct by design wing that is warp free". the main problem with it is the jig consists of the two main spars, is lasercut out of very thick balsa that forces you to cut and trim the pieces so that the ribs fit correctly. The lasercutting isn't complete. I didn't find much issue until I started to sheet the wings, at which point I found a couple things.
- The instructions make it sound/read like you can sheet the wings in midair without having them on a building board... you can't.
- the wings will build flat as long as you pin to the board right side up. although it looks like you can invert the wing to sheet the bottom, you can't, the sides of the jig are not parallel and your wing will get about an 1/8" warp. so when sheeting the bottom wing... glue the sheet in place.. tape it tight the to the wing and then re-pin the wing right side up on the building board to dry
pay close attention to W1, the rib that joins the two wing halves. you are relying on the jig here to get your dihedral correct, however the ends of the jig "spars" are one place where you are forced to use your exacto to cutout the lasercut parts. if you cut wrong, you set your dihedral wrong, and there is NO place in the planes that gives you an indication of how much dihedral to use.
outside of that there are a boatload of mistakes in the instructions... when in doubt.. look at the plans for the right way to do things.... I gotta get some more pics up here of my progress... we are close to being ready to go flying!
the wing builds in a jig that is part of the construction. the ribs and main spar and there is a trailing edge spar all interlock together to give you a "correct by design wing that is warp free". the main problem with it is the jig consists of the two main spars, is lasercut out of very thick balsa that forces you to cut and trim the pieces so that the ribs fit correctly. The lasercutting isn't complete. I didn't find much issue until I started to sheet the wings, at which point I found a couple things.
- The instructions make it sound/read like you can sheet the wings in midair without having them on a building board... you can't.
- the wings will build flat as long as you pin to the board right side up. although it looks like you can invert the wing to sheet the bottom, you can't, the sides of the jig are not parallel and your wing will get about an 1/8" warp. so when sheeting the bottom wing... glue the sheet in place.. tape it tight the to the wing and then re-pin the wing right side up on the building board to dry
pay close attention to W1, the rib that joins the two wing halves. you are relying on the jig here to get your dihedral correct, however the ends of the jig "spars" are one place where you are forced to use your exacto to cutout the lasercut parts. if you cut wrong, you set your dihedral wrong, and there is NO place in the planes that gives you an indication of how much dihedral to use.
outside of that there are a boatload of mistakes in the instructions... when in doubt.. look at the plans for the right way to do things.... I gotta get some more pics up here of my progress... we are close to being ready to go flying!
03-18-2013, 05:25 PM
#27
RE: Great Planes RV-4 Build w/ pictures
So this build was to get back into it. I'd been away from the hobby basicaly through my 20's... too pre-occupied with Jack Daniel's and boobies I guess :-) And part of what it was was a build to remember what I'd forgotten. Today I learned that I had forgotten what order to cover/install hinges
Not a huge issue, I had gone with the dubro nylon hinges and pinned them in with toothpicks. In my eagerness to get coverring I forgot that in order to pin them I would need to do that prior to covering .... so we screwed that up. No biggy, a couple ironed on circles and most will never notice the toothpicks...
Got some other things done as well. Got the 10gx and ignition installed.
And my functional dash is now... ahem.. ermm... well.. functional...
The left is a voltwatch that will be installed on the receiver, the right is the LED from the RCEXL electronic ignition kill/enable. I had thought of a 2nd installed voltwatch for the ignition battery, but then I decided it really wasn't worth it.
I ended up keeping the stock wingtips. Lots of filler/ sanding to get them to blend to shape... and then spray paing. the aileron and flapps are installed here and pinned.. I remembered to do it right this time :-) and we won't have issues with seeing the pins.
Again, its obviously not perfect.. I'm really trying to just get this in the air and ready so when our field clears I'm ready to go flying. Things like painting the wingtips and cowl I quickly said "good enough" on where if I was trying to make this plane really pretty I would have spent a good bit more time on this.
Not a huge issue, I had gone with the dubro nylon hinges and pinned them in with toothpicks. In my eagerness to get coverring I forgot that in order to pin them I would need to do that prior to covering .... so we screwed that up. No biggy, a couple ironed on circles and most will never notice the toothpicks...
Got some other things done as well. Got the 10gx and ignition installed.
And my functional dash is now... ahem.. ermm... well.. functional...
The left is a voltwatch that will be installed on the receiver, the right is the LED from the RCEXL electronic ignition kill/enable. I had thought of a 2nd installed voltwatch for the ignition battery, but then I decided it really wasn't worth it.
I ended up keeping the stock wingtips. Lots of filler/ sanding to get them to blend to shape... and then spray paing. the aileron and flapps are installed here and pinned.. I remembered to do it right this time :-) and we won't have issues with seeing the pins.
Again, its obviously not perfect.. I'm really trying to just get this in the air and ready so when our field clears I'm ready to go flying. Things like painting the wingtips and cowl I quickly said "good enough" on where if I was trying to make this plane really pretty I would have spent a good bit more time on this.
03-18-2013, 05:32 PM
#28
RE: Great Planes RV-4 Build w/ pictures
Another thing I changed in this build was the separate control horns for the elevator. We joined the elevators in the center using 3/32" music wire and a spruce strip and went with 1 control horn.
Why? I don't know... its a .40 sized plane... it doesn't need dual control horns on the elevator.... its not like you gain anything since they are attached to the same servo..... it adds more linkages and places for slop/ issues with setup that aren't needed on a small plane.......i got the routing of the control horn tubes wrong so it was impossible to hook up the right side horn...go by the plans folks...not the book. ( there is supposed to be some humor in this last statement if you couldn't tell.... basically I screwed up and this was my fix )
03-20-2013, 04:50 PM
#29
RE: Great Planes RV-4 Build w/ pictures
greatplanes also used the double rods on the extra 300s which is only a 62inch wingspan.i guess they figure the 2 horns and threaded clevis's allow for fine adjustment....but personaly i agree the elevators pushrods are overkill and you did remove some weight that wass full length of the fuse. win..win change.
i am thrilled the kit arrived today and my daughter was home to bring it right in the house. if it arrived yesturday,the rain would have soaked the box through. i put all the piece's of the old kit away in box behind the furness again . the first impression of the new kits wood looks good. some minor warp in the diecut sheets,but shouldn't need replacing.
i'm building the fuse first since the plan is already on the table under protection sheeting. i put the cowel halfs together already and wil wait to bondo it till i trial fit it to the nose when built.
hows your build going matt? making any progress?
i am thrilled the kit arrived today and my daughter was home to bring it right in the house. if it arrived yesturday,the rain would have soaked the box through. i put all the piece's of the old kit away in box behind the furness again . the first impression of the new kits wood looks good. some minor warp in the diecut sheets,but shouldn't need replacing.
i'm building the fuse first since the plan is already on the table under protection sheeting. i put the cowel halfs together already and wil wait to bondo it till i trial fit it to the nose when built.
hows your build going matt? making any progress?
03-21-2013, 02:02 PM
#32
RE: Great Planes RV-4 Build w/ pictures
looking great matt!! yeah,it's easy to stay in the workshop building away. all to many nights i'll ccome up from the basement to a slightly annoyed darling wife who encourages my hobby but doesn't want to share my time with the planes...lol.
03-26-2013, 05:34 PM
#33
RE: Great Planes RV-4 Build w/ pictures
Each stripe I tried a different method on to seal it down .... was kind of an interesting learning experience. The new monokote is definitely different than the old here. I found the old much easier to get bubble free monokote on monokote here... Didn't have much luck getting this perfect... good thing its a sport plane.
.
.
03-26-2013, 05:35 PM
#34
RE: Great Planes RV-4 Build w/ pictures
All I need is a radio and this plane is ready to go. My 14SG is on backorder from towerhobbies currently, hopefully shipping out this week. Should be interesting to get that installed and get out flying!
03-31-2013, 05:15 PM
#35
RE: Great Planes RV-4 Build w/ pictures
matt,she looks fantastic!!! just wanted to post that i built the wing halves and am ready to finish sanding the le an join them together. the good news is they came out great!!!! i just glanced at the instructions but fashioned my own ways to complete the tips and mounting block sections.
looking forward to hearing how your flight goes ,try to get some pictures flying.
looking forward to hearing how your flight goes ,try to get some pictures flying.
04-09-2013, 01:08 PM
#36
RE: Great Planes RV-4 Build w/ pictures
bare bones ready for filler,sanding,bondo on the cowel,ect...ect..... i took your advise on the wing and just built it the way seemed right. forget the measurements of the wing tips being tapered . may custom build wing tips or may leave as a clipped wing.
05-05-2013, 03:12 PM
#39
RE: Great Planes RV-4 Build w/ pictures
Got out to the field and maiden'ed the RV-4 today, some before and after pictures....
And the after for flight #1:
still in 1 piece!, so that was good.
The whole"fly it mild or fly it wild" statement on the great planes box is a bit misleading... its more "fly it mild or fly it mild". Its a smooth flying plane, even with full throws though the "snap" rolls were barrel like and spins had to be pretty well coaxed. This with the CG located at the furthest spot back on the plans that was recommended. Overall I'd say its a good plane to get back into the hobby with. Stalls were straight forward, nothing eventful. I messed around with the flaps and was able to hover the plane in a slight headwind which was fun. The plane slows down well without the flaps though soI didn't attempt to use them in a landing. Landings were pretty easy, its solid in the wind and settled right down each time. Knife edges weren't happening, it held well but would slowly lose altitude, not enough rudder to really keep them level.
The 10GX ran well, its a bit of a deceptive engine/plane combo. Wasn't really that fast , however pulling vertical there was easily 200-300 feet of altitude gained before it would stall out. Will take some getting used to, however mistakes are readily corrected since it is such an easy flyer.
At 6.5lbs it does feel a little bit heavy in the air.....like flying a warbird without the nasty tip stalling tendencies.
And the after for flight #1:
still in 1 piece!, so that was good.
The whole"fly it mild or fly it wild" statement on the great planes box is a bit misleading... its more "fly it mild or fly it mild". Its a smooth flying plane, even with full throws though the "snap" rolls were barrel like and spins had to be pretty well coaxed. This with the CG located at the furthest spot back on the plans that was recommended. Overall I'd say its a good plane to get back into the hobby with. Stalls were straight forward, nothing eventful. I messed around with the flaps and was able to hover the plane in a slight headwind which was fun. The plane slows down well without the flaps though soI didn't attempt to use them in a landing. Landings were pretty easy, its solid in the wind and settled right down each time. Knife edges weren't happening, it held well but would slowly lose altitude, not enough rudder to really keep them level.
The 10GX ran well, its a bit of a deceptive engine/plane combo. Wasn't really that fast , however pulling vertical there was easily 200-300 feet of altitude gained before it would stall out. Will take some getting used to, however mistakes are readily corrected since it is such an easy flyer.
At 6.5lbs it does feel a little bit heavy in the air.....like flying a warbird without the nasty tip stalling tendencies.
But then again, so does the full scale!
