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        Discussion Funbat, Simple KFm2 Combat plane

#1 jhtitan Feb 06, 2011 06:15 PM

Funbat, Simple KFm2 Combat plane
 
Heres a link to plans for my FunBat. This is based off the Blue Funder with changes made to incorporate my build style and laser cut motor mount.

I built mine with a Micro Park Jet from Grayson and fly it with 2 servos on a 6x4 APC prop and a 1300 mAh 3s LiPo.

its capable of VTO and flew great.

Plans can be gotten here as well as CNC cut kits of this and a few other airframes.

http://bloodymicks.com/Plans/plans.html

I will post some pics of my next build when I get it going, which should be soon.

Jon

#2 jclassic1 Feb 09, 2011 07:10 AM

Hi Jon,
just printed off the plans for the FunBat and plan to build it from 6mm depron.
I want to use a BW rewound 1500kv motor and 3 cell 1000mah lipo.
Will probably just use my normal Kfm2 airfoil with the two bits of foam stuck together with double sided tape.This one fits right into my ideal size for the field I fly from.Might be a bit fast for me but with the BW I can always go to 2 cell and a big prop for a bit more relaxed style of flying.

Keep you posted on my progress.

#3 jhtitan Feb 09, 2011 07:25 AM

jclassic1

Cool, This plane flew great, I have been wanting to try it without the spar myself. The motor I used was more for the nose weight so be prepared for it to be tail heavy with the small BW motor. I am anxious to see your build and hear a flight report or see a flight video.

its such a simple build. good luck with it and post some pics if possible.

Jon

#4 jclassic1 Feb 09, 2011 07:48 AM

Hi Jon ,if it is likely to come out tail heavy I may look at extending the nose a bit.Do you have your electrics installed inside the fuselage.

Plan went together great so now I am off to check how much foam I have left.

John

#5 jhtitan Feb 09, 2011 08:32 AM

on my prototype I installed the ESC on one side and the RX on the other and the battery in between them. just to get everything as far forward as possible. I few of my flyin buddies have built theirs with a little further aft CG than I did and they still flew good, but too far and it was very uncontrollable.

Plane weighs 15oz as I built mine and can handle a bit of extra weight if you need to add a little lead or something to get CG right.

Heads Up rc had a motor that was really inexpensive compared to the Micro Park Jet that I want to try. seemed to spec out close to the Micro in weight and thrust. not sure if your interested but heres a link anyway :) I am going to try this one soon.

http://www.headsuprc.com/servlet/the...ushless/Detail

should be a bit slower and plenty of thrust for VTO's without going too big on a prop.

I have also considered adding a little length to the nose as well, if you go that route let me know how much you added and how it worked out.

Jon

#6 ZackJones Apr 27, 2011 07:01 AM

Jon,

What do you think of this motor/esc combo: 2408-21-B Motor / ESC

#7 jhtitan Apr 27, 2011 07:38 AM

that one should be fine, maybe not VTO but should fly great, My prototype (which I was flying til recently) had a micro park jet and I tested it with a 2212-06 both were way over kill on power.

post some pics of the build I would love to see them.

Jon

#8 gatorlynch Apr 27, 2011 07:58 AM

I plan on using a 2410-12D with a GWS 9X5.

http://www.headsuprc.com/servlet/the...lectric/Detail

Mine is being made out of 4mm coroplast - so it'll be heavier than its' foam brethren.

Tim

#9 jhtitan Apr 27, 2011 08:00 AM

I have seen the foam version weigh anywhere from 9oz all the way up to over 17oz and they all flew great. I can't wait to see a coroplast version. which is funny cause I was just trying to figure out if I have enough signage laying around to make one :)

Jon

#10 rayrz Apr 27, 2011 04:01 PM

Cg
 
hi there,

I build the funbat also....but i don't gettit how the CG is placed...

Where do you leave the battery? all the way in the front?

normaly the cg is 1/3 off the wing??? at the front.

please somebody...i do not get it right.


greeting ray

#11 jhtitan Apr 27, 2011 04:05 PM

Quote:

Originally Posted by rayrz (Post 18086750)
hi there,

I build the funbat also....but i don't gettit how the CG is placed...

Where do you leave the battery? all the way in the front?

normaly the cg is 1/3 off the wing??? at the front.

please somebody...i do not get it right.


greeting ray

yea I mounted the battery in the nose although I will say the CG is pretty forgiving on this plane. still not sure how Chad, from Flight Test, got his battery that far back on his.

I have not played around with the CG much but one of the guys I fly with has his back about .5" or maybe a bit more than that from where I have it marked. His flew great as well.

Jon

#12 rayrz Apr 28, 2011 07:48 AM

If you see the video from Flite-test good, then you see that the orange plane from Josh has a landing gear. I think then that the cg is in the back, instead the front.

De Green one is the normal one. 2 Servo's on the top. And i think also that the battery has to be in the front. i use 800mah 3s lipo. but my plane is still not good CG. is hanging backwards.

Somebody more idea??

greeting rAY

Picture's are following


Quote:

Originally Posted by jhtitan (Post 18086789)
yea I mounted the battery in the nose although I will say the CG is pretty forgiving on this plane. still not sure how Chad, from Flight Test, got his battery that far back on his.

I have not played around with the CG much but one of the guys I fly with has his back about .5" or maybe a bit more than that from where I have it marked. His flew great as well.

Jon


#13 jhtitan Apr 28, 2011 07:57 AM

Quote:

Originally Posted by rayrz (Post 18092320)
If you see the video from Flite-test good, then you see that the orange plane from Josh has a landing gear. I think then that the cg is in the back, instead the front.

De Green one is the normal one. 2 Servo's on the top. And i think also that the battery has to be in the front. i use 800mah 3s lipo. but my plane is still not good CG. is hanging backwards.

Somebody more idea??

greeting rAY

Picture's are following

How far back is your CG? I listed CG at 1.75" back from leading edge, this is right at the spar location marked on the plans. I do know it will fly at a little over 2" back, one of my test builders has a tendency to build tail heavy. he mounted both servos behind the step in the wing. With a 1300mAh 3s in the nose compartment his all fly great. It is a pretty forgiving plane.

The builds in the Flight test video did use lighter servos than I used as well as a smaller LiPo, 3s 500 mAh I use a 3s 1300-2200 mAh. At 27" WS it can handle a bit of extra weight so don't be afraid to add a little if you feel you need it to get CG.


I can't wait to see pics

Jon

#14 Sammy70 Apr 28, 2011 10:23 PM

Very cool, simple plane Jon!

Did you ever try the EMAX CF2822 motor? I may build a couple of these and would like to keep the power system cost low, so that little Emax looks great if it's heavy/powerful enough...

#15 Ottomite Apr 28, 2011 11:51 PM

3 Attachment(s)
After seeing the plane on Flight Test I decided to give it a try.
She looks nice given that this is my first ever plane build :D

Im using a 1780kv motor with a 7x3.5 prop build using dollar tree foam i will add a wooden dowel to reduce the wing droop when i get a chance and im waiting on my batts to come in to maiden her :D

Yall think the 7x3.5 prop will work on this plane ? as soon as i maiden her i will build a 2nd one and do some combat flying with a friend :D


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