Great Planes Giant Citabria GP/EP ARF 85"
12-25-2014, 05:46 AM
#378
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I have not posted here for some time now. Not a lot to report, a few weeks ago my VVRC 40cc twin decided to break down. Only about 12 flights and a connecting rod bearing went out. I would have fixed it my self but sent it in under warranty. Should get it back in two more weeks.
Also, I sent a pair of LG to Graph Tech RC about a month ago. Did not hear back until recently. The owner had been out sick and just got back about two weeks ago. So I would think he is still backed up on orders so I would not expect a CF LG replacement anytime soon. I will contact him in a few more weeks to check on that.
The low bounce tires are a good addition. Found out the hard way that more clearance in the wheel pants are needed. I also found a crack developing on the firewall support rails and glued in some gussets. So now it seems that all the minor problems are being addressed. I just need my motor back.
Also, I sent a pair of LG to Graph Tech RC about a month ago. Did not hear back until recently. The owner had been out sick and just got back about two weeks ago. So I would think he is still backed up on orders so I would not expect a CF LG replacement anytime soon. I will contact him in a few more weeks to check on that.
The low bounce tires are a good addition. Found out the hard way that more clearance in the wheel pants are needed. I also found a crack developing on the firewall support rails and glued in some gussets. So now it seems that all the minor problems are being addressed. I just need my motor back.
12-29-2014, 07:33 PM
#379
I have about 20 flights as of today ( 3 flights today ) here is the update.
All the firewallbox mods are holding just fine, the TNT gear is holding its shape even after a few not so good landings, the low bounce Dubro tires are a big help, the tail wires needed adjustments again but minor ( loose ), two of the windshield magnets came loose and they were glued back on, the tail wheel and bracket are holding fine.
I said it before, all the issues with this airplane are a thing of the past, now I go to the flying field just to fly with no concerns at all, flying the Citabria is so much fun, with the CG right behind the spar inverted flights needs just a touch of up on the stick, slow flights only required about 1/4 of the stick, a 10 minutes flight burns 3/4 of the gas tank, I'm using the AT ibeck and a 2500 mh Li-Fe, each 10 min flight uses about 160 mh per flight.
At the field installing the wing has become easy and fast, no holes on the fuse, the wing is in good shape and all the screws and nuts are where they are supposed to be.
Well, from now on is going to be fly, fly, fly.
Happy landings.
All the firewallbox mods are holding just fine, the TNT gear is holding its shape even after a few not so good landings, the low bounce Dubro tires are a big help, the tail wires needed adjustments again but minor ( loose ), two of the windshield magnets came loose and they were glued back on, the tail wheel and bracket are holding fine.
I said it before, all the issues with this airplane are a thing of the past, now I go to the flying field just to fly with no concerns at all, flying the Citabria is so much fun, with the CG right behind the spar inverted flights needs just a touch of up on the stick, slow flights only required about 1/4 of the stick, a 10 minutes flight burns 3/4 of the gas tank, I'm using the AT ibeck and a 2500 mh Li-Fe, each 10 min flight uses about 160 mh per flight.
At the field installing the wing has become easy and fast, no holes on the fuse, the wing is in good shape and all the screws and nuts are where they are supposed to be.
Well, from now on is going to be fly, fly, fly.
Happy landings.
Last edited by CARS II; 12-29-2014 at 08:59 PM.
12-30-2014, 10:20 AM
#381
I'm using a Xoar 19/8 right now, I used a 20/8 before but it was broken because of the main gear issue, I like the 20/8 better, makes the airplane fly slower yet it has a punch on verticals, the 19/8 is also good, it makes the airplane go vertical forever, I think the main difference between the two is speed and clearance to the ground.
I'm going back to the Xoar 20/8 soon.
I'm going back to the Xoar 20/8 soon.
01-07-2015, 05:51 PM
#383
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My motor has been replaced with a new one from VVRC, it will be here early next week. While waiting I did a modification to attach my GoPro. There are two small screws that go into the mount from underneath to help secure the wood mount to the plastic mount. I would not rely on the stick on mount only. It is also foam backed and tapered to match the dihedral in the wing. A copper foil box that goes around 5 of the 6 sides of the camera will block RF noise from interfering with the receiver. The data stream rate is so high it generates RF noise. I learned that the hard way.
01-08-2015, 11:27 AM
#385
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Some people get different results, but I personally believe the gear is only good for near perfect landings. I know of two other people at my field that have this Citabria. two out of three of us have had problems. The third guy has only flown it once and the landing was perfect. So you can not judge by that.
TNT wants $47 which I think is a little high. Tower does not have a replacement at this time I believe. I am waiting on Graph Tech to come out with a CF gear. So what ever you want to do it will either be some money or some time. You could fly with what you have and see what happens. But use a cheap prop until you know for sure.
TNT wants $47 which I think is a little high. Tower does not have a replacement at this time I believe. I am waiting on Graph Tech to come out with a CF gear. So what ever you want to do it will either be some money or some time. You could fly with what you have and see what happens. But use a cheap prop until you know for sure.
01-09-2015, 09:51 PM
#386
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I got mine about a week ago looking forward to fly this bird it's always been one of my favorite . What covering is on the plane .? On the gear I have a sheet of T 6 aluminum in the shop I'll use for the new gear . If I don't like that I'll do a mold and pull some carbon fiber ones . I was thinking maybe use the ones from the kits and sandwich it between some carbon fiber . Not sure Yet what i will do
thanks JIM
thanks JIM
Last edited by Redtail_Customs; 01-09-2015 at 09:56 PM.
01-15-2015, 03:56 PM
#387
Join Date: Dec 2005
Location: Shrewsbury, MA
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Just got done reading the thread in full. I appreciate all of the feedback from those who've built and flown it. I'm already creating a list of modifications based on information in the thread. I'm likely to make major modifications to the struts. I'd like them to be able to collapse so that I can store the wings in a wind bag and easily transport them. It should also remedy the assembly issue as I could get the wings seated with the struts well clear of the fuselage. Beefing-up the engine box is SOP for a gasser. I'm also thinking about forgoing the cockpit, tinting the windows dark and installing a smoke system (likely where the pilot bust would sit). I'll have to examine the fuselage to see if I can get a tank and smoke fluid pump mounted on the CG. As a finishing touch, I plan on replacing all sticker graphics that go on the exterior of the plane with laser-cut vinyl.
For power, I'm leaning towards the O.S. 33 GT. Although, I haven't made up my mind on that. I have a bunch of Hitec 645MG servos looking for a home, so they'll go in this bird. Lastly, a Spektrum receiver. Probably 9 channels (Aileron-2, Flap-2, Elevator-2, Rudder-1, Throttle-1, Optical Engine Cut-1). Oh, and one beefed-up landing gear...
I'll share some photos as I get going with the build.
01-16-2015, 09:55 AM
#389
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According to FedEx, my plane will arrive on Tuesday. The struts will be one of the initial things I'll be working on. My thinking is to find a way to adapt the strut hardware that Hangar 9 uses on its 1/4 scale cub. It's white and I think it'll be the correct size. That style of hardware is good for using pins and keepers. Then I'll have to figure out how to mount it to the Citabria struts. We'll see if that's a workable solution.
01-17-2015, 07:43 AM
#394
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After spending so time looking at the manual yesterday, I think I know how I'll modify the struts so that they can collapse for transportation/storage of the wings.
1. The "L" brackets attached to the wings need to be turned 90 degrees so that the struts can swivel up and down against the underside of the wing. The brackets towards the tips of the wing will need to be bent to 90 degrees and spun 90 degrees. Also may need to be repainted if the finish is damaged while bending.
2. The ends of the main struts and jury struts where they attached to the wing will need to be cut down to accept the hardware for connection to the "L" brackets. They will then need some finishing after hardware installation.
3. The hardware would be threaded rod epoxied into the end of the cut down strut. Then, a heavy-duty ball link is installed on the threaded rod sticking out of the end of the strut. The ball links connect to the "L" brackets on the wings with screws and locknuts. Now the struts can swivel up and down to fold/unfold.
4. Functionally, for installation from the folded position, you'd swing the main struts away from the bottom of the wing and then fold the jury struts upright. From there, align the threaded posts from the jury struts and insert into the main struts, then install nuts. The struts can then be bolted to the fuselage attachment point.
I'm inclined to mock this up using some wood dowel rods in place of the struts to confirm fit & function before I start hacking up the actual struts. I think this method will work and the hardware will be strong enough to withstand the loads.
1. The "L" brackets attached to the wings need to be turned 90 degrees so that the struts can swivel up and down against the underside of the wing. The brackets towards the tips of the wing will need to be bent to 90 degrees and spun 90 degrees. Also may need to be repainted if the finish is damaged while bending.
2. The ends of the main struts and jury struts where they attached to the wing will need to be cut down to accept the hardware for connection to the "L" brackets. They will then need some finishing after hardware installation.
3. The hardware would be threaded rod epoxied into the end of the cut down strut. Then, a heavy-duty ball link is installed on the threaded rod sticking out of the end of the strut. The ball links connect to the "L" brackets on the wings with screws and locknuts. Now the struts can swivel up and down to fold/unfold.
4. Functionally, for installation from the folded position, you'd swing the main struts away from the bottom of the wing and then fold the jury struts upright. From there, align the threaded posts from the jury struts and insert into the main struts, then install nuts. The struts can then be bolted to the fuselage attachment point.
I'm inclined to mock this up using some wood dowel rods in place of the struts to confirm fit & function before I start hacking up the actual struts. I think this method will work and the hardware will be strong enough to withstand the loads.
01-23-2015, 11:42 AM
#397
Originally Posted by [email protected]
My replacement VVRC 40cc twin motor did not last the day. Connecting rod bearings started knocking after the second flight. Very disappointed!
What oil, what oil percentage? what prop? what fuel (octane, ethanol, age, etc.)? better yet, prolly should direct to the FG VVRC40 thread which has over 100 pages of post with hundreds of owners as well as Tom & Supa Tim from VVRC - http://www.flyinggiants.com/forums/s...ad.php?t=83604
Cheers
01-23-2015, 12:58 PM
#398
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Well some friends at the field gave me the 30 questions when the second motor failed. And this is what I had to say. I have 6 gas motors that all use the same gas. (no problem) I use Red Line syn at a ratio of 32:1, 8 OZ for two gal. I get my gas at a place that sells Ethanol free gas just for my airplanes. I get the 87 octane. I use a 19x10 prop for this twin 40cc which is recommended. I don't firewall it 100% of the time, and I have good air flow. At least it worked for 14 flights the first time. The motor ran great! I just don't understand. The next time I will run with the cowl off and try tweaking the carb a little. For what, I don't know, but I will be using my temp sensor often.
I believe this plane is cursed! The number of and verity of problems exceeds all other planes in the past. My throttle servo failed twice. Two new out of the box Hitec servos. Again my radio failed during the first attempted maiden. The throttle ratchet failed. No servo response displayed on the radio. Sent it in and they said NTF. I made them open it and clean the ratchet. Now it works just fine. My NAV lights failed because I used 6.6V rather than 4.8V on the receiver. Did not know that. And the LG issue is still unresolved, just have to make near perfect landings. But all through it all, my Citabria is still not scratched.
The first photo shows air intake. Notice that the center air scoop is blocked off. this causes ALL the air to enter at the cylinders. The second photo shows one side where the plugs extent past the cowl. This also allows air to exit. The third photo shows the bottom where the exhaust stacks extend past the cowl and also allows air to exit the cowl allowing more air flow. I don't see any problem with this setup, but some will say the more flow, the better. I say, this is enough and it is a scale model, not a high performance aircraft, and I don't want to butcher the cowl up.
Anyone see a problem with my fuel, prop, setup?
I believe this plane is cursed! The number of and verity of problems exceeds all other planes in the past. My throttle servo failed twice. Two new out of the box Hitec servos. Again my radio failed during the first attempted maiden. The throttle ratchet failed. No servo response displayed on the radio. Sent it in and they said NTF. I made them open it and clean the ratchet. Now it works just fine. My NAV lights failed because I used 6.6V rather than 4.8V on the receiver. Did not know that. And the LG issue is still unresolved, just have to make near perfect landings. But all through it all, my Citabria is still not scratched.
Anyone see a problem with my fuel, prop, setup?
01-23-2015, 05:34 PM
#400
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Any air intakes should be directed to where the cooling needs to be, the cylinders. There are two air intakes directly in front of the cylinders. All other holes in the cowl are exits, four of them.