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Old Oct 06, 2011, 12:43 AM
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Gamerjoe's Avatar
United States, CA, Diamond Bar
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I have my foam core version built, but I am now thinking that foam core was the wrong choice because I cannot get the CG correct without adding 84g of weight to the nose. Ugh
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Old Oct 06, 2011, 08:24 AM
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United States, OH, Eaton
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Originally Posted by Gamerjoe View Post
I have my foam core version built, but I am now thinking that foam core was the wrong choice because I cannot get the CG correct without adding 84g of weight to the nose. Ugh
Wow, that's alot of dead weight to add. What's the total weight? It probably would balance perfectly if the paper was stripped. Is there a way you can add some length to the nose?

Chris
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Old Oct 06, 2011, 03:44 PM
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Originally Posted by chris1379 View Post
Wow, that's alot of dead weight to add. What's the total weight? It probably would balance perfectly if the paper was stripped. Is there a way you can add some length to the nose?

Chris
Unfortunately I do not have a scale, but I went ahead and lengthened the nose 3/4" using epoxy and 1/8" plywood as reinforcement. That should allow me to get to CG without adding weight or with adding very little weight. I'll post some pics soon when completed.
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Old Oct 08, 2011, 01:15 PM
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How do you guys trim your Funbat for level flight. Mine flies level at a fairly slow speed but heads for the heavens when I jump on the throttle. I trimmed my elevator for level flight about 3/4 throttle. Trying to hold consistent down elevator at high speed is a little too difficult for me. This way I can do high speed passes with the plane going up after it gets past me. Inverted flight is easier too and needs much less elevator correction.

If you trim your plane for higher speed, be sure and add a switch for takeoff. I mixed my DX7 gear switch to bring the elevater back to level. Once it gets airborne I flip the switch back. I also use it for low speed flying and landing. I experimented a little with flaperons but I haven't reached a conclusion yet.

Chris
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Old Oct 08, 2011, 01:19 PM
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I would add a little down thrust to your motor.
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Old Oct 08, 2011, 02:09 PM
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Originally Posted by TBolt View Post
I would add a little down thrust to your motor.
I could but this can cause 2 issues with a higher speed plane. The upward pitch of the plane increases with airspeed, not thrust. If the plane is flying full throttle and level with downthrust and the throttle is suddenly cut, it will pitch upward and stall. Just remember to avoid sudden throttle changes. Also since this plane is hand launched, you will need a few seconds to be on both sticks. Since there is not much airspeed at launch, the downthrust can pyle drive it into the ground. A switch with a little up elevator helps with this.

Does your Funbat tend to pitch up more when upright than inverted? I think most high-wing planes do unless I just didn't get something straight.

Chris
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Old Oct 09, 2011, 05:31 AM
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Washington MO
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Originally Posted by Gamerjoe View Post
I have my foam core version built, but I am now thinking that foam core was the wrong choice because I cannot get the CG correct without adding 84g of weight to the nose. Ugh
I am guessing you went with elmers foam core. The posterboardvbacker makes it a bit stronger but.adds a lot of weight. On this plane with.the.ch so far forward that will make it harder to balance.

Once.you get it balanced you should have no problems flying with the extra weight. I have flown this design under many different weight loads with great success.

Jon
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Old Oct 09, 2011, 05:39 AM
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Washington MO
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Originally Posted by TBolt View Post
I would add a little down thrust to your motor.
I agree, sounds like you do need some down thrust. I think you mightnbe over.concerned.with thrust angle. I agree with pitch and speed changes. But.these.are brought.on by trimming elevator more than motor. If it glides level and nose up when on the throttle some down thrust will get you fixed up. It may have a bit of up in it during the build I have done it myself many times. Now I always trim control aurfaces and motor angle as needed on the first couple flights.

Just my 2 cents
Jon
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Old Oct 09, 2011, 09:58 AM
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OK, so the Funbat shouldn't tend to pitch up with the elevator level? That was my original question but I got off on a tangent somewhere.

Chris
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Old Oct 09, 2011, 11:39 AM
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OK, so the Funbat shouldn't tend to pitch up with the elevator level? That was my original question but I got off on a tangent somewhere.

Chris
No, you should be able to get her to fly level with cg and some motor angle. With cg correct I have been able to trim a touch of up elevator to get it to fly good and level but its better if needed to trim the motor angle.

Jon
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Old Oct 09, 2011, 02:58 PM
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Bristol,UK
Joined Feb 2007
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Hi Jon
enjoying my FunBat so much that I'm considering making a larger version. Shooting for 40" wingspan to allow either 2200 3 cell or 1800 4 cell, 40 amp esc and this Turnigy 1700 kv motor
http://www.hobbyking.com/hobbyking/s...idProduct=3885
Should work according to this HK review...
"Using in a funjet, 4cell 1500mah rhino Lipo, apc 6x5.5e prop, Pulls 30amps on a 40amp turnigy esc, speed is 99.3mph in level fligh tested with gps... everything comes down cool, this is a perfect setup for a funjet"
I'm running the same 3 cell set up on my GWS FW190 and it scoots around faster than my Phase 3 F-16!
GWS FW-190 (4 min 17 sec)

Will use 6mm depron KFm-4 wing and will make the wing removable.
What do you think?
Andy
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Old Oct 09, 2011, 06:49 PM
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Washington MO
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Originally Posted by headlessagain View Post
Hi Jon
enjoying my FunBat so much that I'm considering making a larger version. Shooting for 40" wingspan to allow either 2200 3 cell or 1800 4 cell, 40 amp esc and this Turnigy 1700 kv motor
http://www.hobbyking.com/hobbyking/s...idProduct=3885
Should work according to this HK review...
"Using in a funjet, 4cell 1500mah rhino Lipo, apc 6x5.5e prop, Pulls 30amps on a 40amp turnigy esc, speed is 99.3mph in level fligh tested with gps... everything comes down cool, this is a perfect setup for a funjet"
I'm running the same 3 cell set up on my GWS FW190 and it scoots around faster than my Phase 3 F-16!
http://www.youtube.com/watch?v=RuscSvah_qw
Will use 6mm depron KFm-4 wing and will make the wing removable.
What do you think?
Andy
I look forward to seeing it I have been wanting to build a bigger one too, just havent had the time with school and work. Post pics of the build. I think the power system should be fine, I have a 1400 kV Turnigy SK motor I may put on a scaled up build of my own sooner or later.

Jon
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Old Oct 12, 2011, 12:25 AM
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United States, CA, Diamond Bar
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Originally Posted by jhtitan View Post
I am guessing you went with elmers foam core. The posterboardvbacker makes it a bit stronger but.adds a lot of weight. On this plane with.the.ch so far forward that will make it harder to balance.

Once.you get it balanced you should have no problems flying with the extra weight. I have flown this design under many different weight loads with great success.

Jon
It flew great for 2.5 flights. Into the 3rd flight, the battery slipped from the Velcro strap and fell out, pulling the plane nose first into the ground. Its ok though because I want to build it again with lighter foam.
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Old Oct 12, 2011, 08:40 AM
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United States, OH, Eaton
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Originally Posted by Gamerjoe View Post
It flew great for 2.5 flights. Into the 3rd flight, the battery slipped from the Velcro strap and fell out, pulling the plane nose first into the ground. Its ok though because I want to build it again with lighter foam.
I used Dollar Tree foamboard with the paper removed and covered it with packing tape. The front of the fuselage is covered in Extreme tape.
HERE is a link to it. I have built 2 planes this way. It seems to flex more than depron but seems really strong.
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Old Oct 12, 2011, 07:04 PM
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Joined Mar 2011
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fun bat

Hi,

I have a fun bat that I just built. Flew it for the first time tonight with 70% dual rate on ailerons and 70% on elevator.

Had problem with plane porposing. flew just ok at half throtle when I would go full throtle the plane would want to really climb bad. may need to mix in some down elevator as throtle increases.

Have COG at about 2.25 inches back from leading edge

using a 3s 1300 mah battery

this is the motor I am using turnigy 2730-3000
http://www.hobbyking.com/hobbyking/s...idproduct=8620

2 hxt 900 servos

and a mystery 30 esc

http://www.hobbyking.com/hobbyking/s...e_Series_.html

any help would be appreciated to get this thing flying good and level, didnt seen to have a lot of power and you could hear vibration at full throtle, prop is not knicked or anything like that nor is motor shaft bent.

Thanks

Nick
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