Minimal on that size... maybe 1/10 of 1 ounce... heck you could even put lightening holes in it and get it about even...

Nike it and "Just do it"

I mounted my battery in the UCD the following way:

1) I cut a large hole in the balsa sheeting on the fuse bottom, almost the whole width of the fuse and maybe 4 inches long just ahead of the bulkhead in the middle of the fuse.

2) Snip the battery wire and solder in a 12" or so extension.

3) With the plane inverted drop the battery in the hole so it rests on the top of the fuse and is against the bulkhead. CA a piece of balsa sheeting to trap it to the top of the fuse. CA a balsa stick to stop it from sliding forward.

4) CA the sheeting back on the fuse bottom

5) Cover with monokote trim sheet or monokote.

Took about 30 min. I have no access to the battery but I don't need it. I mount most batteries in the back of the fuse, saves tons of lead.

Just another option.

First of all, you should determine how much lead you need to add to the tail. That has a long tail moment and you might not need to add much.

Then, if necessary, move the battery pack back. I would put a hatch on the side if you can. If the battery pack weight is on the hatch, putting it on the bottom will pull the screws out on a hard landing.

I don't have one of these planes, but one of the guys in the club does and he can't keep his motor running. I have passed along the comments you guys have made, and I'm sure it will take care of his problem.

This thread had been very interesting.

Regards,

Instead of using corner pieces for the hatch cover I would use full length stock, since move the C&G aft this would be a problem, I might do this on mine, but I have yet to fly it....the weather is still pretty cold, got snow last week....not the usual weather for sure..

coomarlin,
I wouldn't attach the battery to the hatch, this just serves to put additional stress on the hatch, and its securing. I went along the lines of geoharry , but made the hatch removable for future use. I just used the balsa that I cut out as the cover, and glued a retaining frame on the inside of the fus. If you glue the hatch back on, its a certainty that you will require access in the near future

I WOULD recommend attaching to the hatch...

As long as the battery is fairly solidly attached, and liteply is used for both the hatch and corners there's plenty of strength...

Now someone else mentioned instead of corners using full rails...

Thats a good idea.. again VERY minimal weight but it is stronger...

Something liek this...

Admittedly, there's a 100 different ways to accomplish something. I prefer things simple so what I did was to cut out a section on the bottom of the fuse between formers large enough to put a foam wrapped battery where I wanted it. Once opened up, I used pipe insulating foam to wedge everything in tight. Then I used 3 cut to size pop-cycle sticks as cross members between the packed in battery and the balsa edges remaining on the fuse bottom. These were pushed in between the foam and the bottom. This effectively creates a floor for the battery's weight which is structurally sound and won't shift or move with vibration or during flight. Next, I simply ironed white Ultrakote over the opening which can be removed and replaced if you ever need to get to the battery compartment. There is no weight or stress placed on the Ultrakote covering.

Interesting perspectives everyone. I appreciate the assistance. I will continue to ponder this.

I like your approach to these engineering challenges. We think the same way, I am sure.
Would you like to mend the wing on my Extreme Lite, please?

Nosram, I thought you almost had your wing finished? Besides, there is no way I could rival your building skills. BTW, with all the G's you put on your wings I'm sure you'll be using a broom stick for your main spar. Enjoy...

I do, couldn't find a carbon fiber broom stick however

Nosram, they make a softball bat out of titanium that you might consider using. LOL

Mordib, Looked at your picture to lower tank. I cut out 1/16 ply both bottom and sides. Did you cut another round fuel tank hole just below motor mount in firewall or did you just make fuel tubing holes? If you just made tubing holes one would not need to cut the ply out! If you just cut the upper bulkhead brace out, long saw, stand on your head etc. and insert the tank it will fall in line with the lower bulkhead crossmember and you can push the tank in, then back , to rest on the former foreward the landing gear mount. Yes there is some extra fuel tubing from the further aft location however I do not think it an issue. This would negate any cutting. I will run and fly the plane to confirm if an extra inch of fuel tubing, with a correctly mounted tank makes a difference. WHMC

Thanks for the suggestion, I am already using a plastic baseball bat for my Panic biplane's fuselage

Hello everyone, my name is James and I am a 3Daholic. I will be purchasing a UCD 3D and YS 91 today. I have waded through most of this thread and am very much looking forward to expanding my flying skills with this combination. Thanks for all the valuable input so far and I hope I can contribute in some way myself in the future.

"Hello James" the large group of 3DA members say...

You're gonna love the plane James. Now...

Beef up the former that holds the wing dowels and landing gear block with tri-stock both sides and a flat piece of ply, inside, across teh landing gear block area. Maybe even double the holes with ply-discs.

You may want to beef up the landing gear... they're real flimsy... I put a spring between mine and it help tremendously.

No need to modify the tank location with a YS... it has a pump, tho you may wish to move the tank to CG right from the get go.

Find some rigid plastic tubing the same size as the wing bolt opening (or make something up) and glue them around the holes in the wing and bellypan... them bolts are a PAIN in the butt to get to, etc... making these "bolt sleeves" will make it MUCH easier to put in and take out those bolts...

someone needs to make a ucd for g2 cuz i cant get one till next christmas.......i got g2 yesterday instead.....and i'm craving the mouthwatering sent of the UCD....HEHE

I can't believe GP will release the next add-ons disk without including the UCD, but I bet it will be christmas before we see it.

Leonard

Got my UCD today. Due to all the YS .91's being on back order according to my LHS, I opted for the Saito 100. I am a big fan of Saito anyway so this seemed like a good chance to try this new little marvel of theirs. Discussed the Cline regulator with the "experts" at the LHS and they are of the opinion that the regulator is unnecessary provided one clamps off the fuel inlet line while fueling the airplane. Time will tell. Thanks for all the tips. I will incorporate them as I build. Really looking forward to this project. I hope to be flying it by the Azalea Festival Fly In in Muskogee, OK a week from Saturday. No time to chat, gotta build.

I have no problem with an Elevator into a Harrier with my Extreme Lite, however with my U Can Do the Elevator is quite good ( a little wing rock). Transforming into a Harrier with increased throttle starts the wings rocking to an alarming rate. I am using up ailerons with up elevator. Have tried varying the % mix, from 80% to 125%. It doesn't help a great deal. 125% probably wins.
An theories would be most welcome

Put in four or five flight on my UCD today, and when I was putting it back in the car, I heard a solid thumping coming from inside the fuse. The battery was no longer strapped down and was loose inside the fuse behind the wing saddle. It was hanging from the switch. Luckily, I had secured this connection with a piece of braided fishing line. If I hadn't done this, I think I would have lost the plane today.

Moral of the story: Secure all radio connections - it just might save your plane.

Leonard

Alternate Moral of story: Mount battery securely.

Preferably not to the battery hatch

OR preferably... depending on your preference...

For what it's worth I did make a hatch but found my battery (a 1650 mah) was too wide to sit comfortably.

I cut 2 pieces of 1/8" balsa about 1" wide and long enough to cross the fuse and butt up against each side. CA'd each piece on each side of the former that was near the hatch, and used the "stuff with foam technique"

I went to the extra trouble of the "battery floor" to keep the battery area small enough to compact the foam tightly.

I jammed my throws as far as they go and found them to be too much... I was able to get it to snap out several times... which I didn't like none too well...

I guess another moral... DON'T tweak your CG AND max your throws at the same time...

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