Kris' GP Yak-54 buld thread

[JeeUm]

Ok guys, I'm guilty. Totally forgot about the video and I haven't been checking this thread. So anyway, here it is. I'm having issues ripping videos, so the quality is a littly jerky, it's not from being shaky with the camera. This was actually shot using a tripod.

http://www.flyinggiants.com/gallery/data/504/sYak.wmv

[3-d flyer]

Crash..... I got a few pix of what i did on mine on the RCU thread.... i always have trouble with picture resizing here.

Thank JeeUm! It's about time... Just kidding...LOL.... I have been looking forward to that..

Kris, be sure to keep us posted on the swet spot for 3D on the CG!!

[GremlinX]

I bet it flys better with 8oz gone for sure. Get some stand offs and lose another 3 oz.

[3-d flyer]

Hey Kris, where was your CG for the first flights? I know you said earlier on it was 1/4" behind where GP recommends it. Was that 1/4" behind the 5-1/8 start point or 1/4" BEHIND the extra 1/2" you are allowed to move it back? I ask because i cannot believe how tailheavy i'm coming in! D/A-50 upfront, stock muffler, ignitin pack on the engine box, ignition on the box, STOCK spinner..... TAILHEAVY! The TX pack is on the CG right now but after taking a second one and putting it on the nose it is still tailhavey at the AFT most recommended C/G!
Just curios where you started at..... and where you are going to wind up... I am going to take the T/X pack (6vNIMH) and put it on the engine box as well, i'll see where that takes me.... but it's looking like i'm going to need a second pack up there too just to get her in the aft recommended ball park!

Servo on a pull pull in the mid fuse area is looking to be the way to go with this one gents! I am only running a single 5955 back there with 2 5645mg on the elevators. Well, it's looking like my planes diet is going out the window!

[KrisW]

Well. . I have to thank Jeeum fornot showing the Carnage after that horrible landing

But. . as for repairs, I jsut shot some pics of what the repaired area looks like. What I did was to Epoxy all the small pieces of wood back together, as well as I could, then use a dremel tool to grind the area of the repair down about 1/16", then cut out a piece of 1/16" 5-ply aircraft plywood and epoxy it on top of the broken area. This ply is 3-4 times as strong as the original lite-ply plate, and should hold up to normal usage now. But, to further reinforce the area, I dut a piece of 1/2x3/8x1/16" thick aluminum angle about 4" long, and mounted it on TOP of the gear, and then screwed/glued it to the fuselage framework to help support the gear leg from above, and keep it from shifting around. the enclosed pics show the final product.

In 4 flights on Thursday, I had absolutely no gearplate issues, but then again, I had the 8" pitch prop back on the engine, and had some speed during landings so the plane didn;t pull a "kerplop" instead of a landing. I'm sure that elps keep gear plates intact.

Now all i need to do is repair the fuselage skin and recover it with Monokote and you will not be able to tell it was ever damaged, at leastnot fromt eh outside.

[KrisW]

	Quote: Originally Posted by 3-d flyer
	Hey Kris, where was your CG for the first flights? I know you said earlier on it was 1/4" behind where GP recommends it. Was that 1/4" behind the 5-1/8 start point or 1/4" BEHIND the extra 1/2" you are allowed to move it back? I ask because i cannot believe how tailheavy i'm coming in! D/A-50 upfront, stock muffler, ignitin pack on the engine box, ignition on the box, STOCK spinner..... TAILHEAVY! The TX pack is on the CG right now but after taking a second one and putting it on the nose it is still tailhavey at the AFT most recommended C/G! Just curios where you started at..... and where you are going to wind up... I am going to take the T/X pack (6vNIMH) and put it on the engine box as well, i'll see where that takes me.... but it's looking like i'm going to need a second pack up there too just to get her in the aft recommended ball park! Servo on a pull pull in the mid fuse area is looking to be the way to go with this one gents! I am only running a single 5955 back there with 2 5645mg on the elevators. Well, it's looking like my planes diet is going out the window!

I set the cg 1/4" behind the Neutral point they recommended, 3D. Plane flies nose heavy with it right there, but is also very steady in all but the worst cross winds. Its a good starting point for any flyer out there, IMO.

[3-d flyer]

O.K. cool, thanks Kris... i'll be starting out 1/2" back from neutral.... so i should be ok. Needed to add a second 1650NIMH on top of the engine box with the original 1650 up there too just to get her to balance there.... i guess my weight savings is out the door now.. o well it should be good. Thanks

[KrisW]

	Quote: Originally Posted by 3-d flyer
	O.K. cool, thanks Kris... i'll be starting out 1/2" back from neutral.... so i should be ok. Needed to add a second 1650NIMH on top of the engine box with the original 1650 up there too just to get her to balance there.... i guess my weight savings is out the door now.. o well it should be good. Thanks

Spacing the engine forward an additional 1/4" would really help the cg shift 3D. It's amazing what moving 4 lbs that small amount will do for the planes cG. Then you could probalby play with battery packs and reduce them for a slightly lighter plane. I do this all the time, since I use the lighter BME engines, in order to get planes to CG properly.

[Ialwayscrash]

I am going to try just that. I have a set of spacers that are going to put the thrust washer at 7 1/2" I was going to get something different but I think I will try that because I want to use 4 servos in the rear. I am using a Fox 2.4 it weighs 58 oz with everything including the battery. I let everyone know how it turns out.

[Ialwayscrash]

Boy this thread sure died. Well my progress is slower than I wanted but I am making a little.I will post this just in case someone is still following this thread. First I think I solved the tank over cg problem. I bought an Sullivan S391 18oz boat tank. I put a small piece of foam on it and it still slides under the wing tube nicely I only had to trim a slight amount from the forward former for clearance for the fuel lines. I am going to try and post of photo of the tank install and my gear strengthing mods also but I do not know if it will work. Also they are not the best quality but it is the best my camera will do. To strengthen the landing, I laminated 3 sheets of 1/8 plywood together and used the two inside landing gear screws to hold it down. I then took some 1/4 inch plywood and epoxied it to the fuselage box side and the laminated plate. I also epoxied some 1/8 ply on the the outside of the Fuse box and ran some servo mounting screws through both to try to disperse the energy of landing as much as possible. My name here says it all. SUNP0001.JPGSUNP0002.JPG

[3-d flyer]

Looks good.... Mine is still sitting here awaiting the maiden, our field is still closed awaiting new blacktop ....
I did the same thing awhile ago with a 16oz Dubro tank and got it under the wingtube... i have trouble posting pix here on the giants so i never did....my mods are on RCU.... As well i did a very similar thing with the gear area for strength..... should hold up good! However i think the gears themselves are kind of bendy, w'ell see..... good luck!

[RyanW]

I have experienced the same problems with the weight as 3DFlyer. I have a Webra Bully 35cc up front and according to the published weight of the Fuji 43, I was going to be 1/2 lb heavier in engine alone, so I installed the rudder servo in the back, etc. Well, I had to put two of the giant JR 1800 nicad extra packs on top of the motor box just to get it in the area of an acceptable cg. AUW? 16 lbs, 12 oz!!!! I really would like to shift the receiver batteries, but don't want to get any closer to the ignition because of interference (I am at 12" now). Just wonder where you guys finally ended up with CG settings and AUW?
-Ryan