I was just thinking about the validity of the method i just for finding the CG that this method should work for a rectangular wing also.
But if done in a rectangular wing the point of intersection would be the center of the wing which is incorrect.
So i did some more research and found out this
I found out the MAC correctly and did a mistake after that.
The dashed line passing though the MAC is correct "but" its projection on the center line of the a/c was incorrect.
Now what needs to be done is that the CG needs to be around 30% of the MAC line so now, did the necessary corrections.
I am going for a region of 40% to 30% for the cg in my ac.

@augustinev:

Quote from: augustinev on July 01, 2011, 09:56:13 AM
the new cg too is too far forward

problem fixed for now
Thank you sir for the heads up.

Quote from: naatumach on July 01, 2011, 03:38:56 PM
I was just thinking about the validity of the method i just for finding the CG that this method should work for a rectangular wing also.
...

I was gonna ask you the same thing.
So, for a rectangular wing the CG needs to be around 30% of the MAC line, right?
Is this the standard procedure for all types of wings?

@Swapnil
Yes as it turns out CG needs to be around 30% of the MAC.
This procedure should work for all planforms as it is working for rectangular, trapezium or tapered planforms.
I made an error in terminology earlier "MAC line" is incorrect, MAC is already a line, its the chord, it is just MAC

I returned from Bangalore today evening.
Couldn't resist till morning so i have started building the a/c.
I have changed the proportions just a little bit, increased the wingspan.
Attached are two pics-
Pic 1: Pattern of the parts that can be cut out from this sheet, along with the motor mount. ( the motor mount is kept only for show, its position will be decided after the structure is complete.
Pic 2: Kind of Stencil for the vertical stabilizers. I shall cut them out place them in the fuselage, align them using this stencil and glue them together and remove the stencil gently.

Pic 1:Assembled body, except all electronics.
Pic 2:Electronics bay. The motor and battery will be covered, only the servos will be showing. I could have hidden that in the bay itself, but i wanted to maintain all the weights in a region instead of the line. The cover will rest on bottom of the vertical stabilizers and will be removable for easy access.

I need a sharper blade this needs a replacement desperately

Waiting for the stores to open will get the soldering wire and setup the gold connectors.
Pic : Electronics bay.

really nice one!!!! wat thicknees foam hav u used... i think its too thick....... more than 5 mm...

since u have pretty big prop, be sure to care that while landing it should not touch ground, otherwise it will damage ur motor mount support!!!!

@ashJR7202:
Thank you
the foam is 12mm thick. when i ordered the foam i was not sure for what thickness would be suitable so i settled for this assuming that it would be the strongest.
the prop sticks out around 3.5inches below the belly, i shall try to be careful in landing it.

Build is complete.
The motor and battery will remain exposed.
I have to do some sanding along the edges
I am thinking of a paint scheme as just a black border along all the edges, and some numbers on the tail.

Now just waiting for the wind to stop, it is VERY windy outside.

completed within a day..omg

hi,

nice effort, but i suggest you see the 6mmflyrc.com for details.

regds


http://www.parkjets.com/f-22-tomhe/

Waiting for the winds to stop, now also waiting for the sun to rise
I decided to put some decor on the a/c with my quintessential logo just to pass the time.
The a/c is good to go. i just need to connect those two wires coming on the top of the fuselage.
I also took the liberty of making a facade just under the motor with paper.

Also, it is not a pusher-type model.

As it turns out, i changed the configuration because of which the cg has moved way back because of which i have to put some dreaded balast.
Here's hoping for the best.

There is a thin line between theory and practical.
The theoretical CG i calculated was correct. The practical design which i speculated pushed the CG back making the a/c tail heavy.
Since i made a mock earlier i am glad i only ran into one problem which i think is a bargain atleast for my third build.
If i didnt learn from each build then i wouldnt have anything to build the next time.

I was able to make this a/c from all the remaining depron i had. So now i still have one full depron sheet which is untouched. So i'll make one more, but only after test flying my yf-22.

After reviewing http://www.windfinder.com/forecast/chennai_madras_airport i came to a conclusion that the winds will not calm down anytime soon.
Ergo, i decided to go now.
I already knew that the a/c was too tail heavy so i had made the necessary adjustments before going.
After reaching the field i very cautiously launched the a/c at 75% throttle. It rose, looped at 8ft and then i cut the throttle and crash landed it.
Obviously the culprit was the misaligned CG.
So i returned and decided that instead of adding a ballast i should reposition the battery.
Had a very successful glide test.

I could not sit idle so i decided to film this glide test to check and confirm the CG.

Confirming to ashJR7202's warning and my beginner skills.
I damaged the place where the motor was mounted.
So i shifted the motor above the a/c.

Also the battery's wire is getting loose from inside, which is troublesome and i have to helplessly place the battery on the nose to get the correct CG.

The motor is pulling the a/c but something isnt making sense. Gotta figure something out.
The problem was no matter what i did the a/c was pitching up. But now after shifting the motor up, i think that issue has gone, because earlier the major part of the prop was below the a/c. Now i guess the forces are balancing.

Aesthetics have taken a back seat.
I shall not give up. I have 9more days at home gotta make the best of it.
Can i please get some more blessings here. I could use a little.

I was thinking about what all could be going wrong and i realized one more thing i was doing wrong.
According to me, I strayed from the BASICS. I didnt put airfoils on the aircraft.
So i added a KF-2, with the hope of easing the burden on the motor and control surfaces.

I stayed up all night so that i could go to the field and fly at 0530hrs.

Flight 1 - I launched the a/c and the motor shut off 2feet away.
Flight 2 - I launched the a/c and the motor shut off 2feet away, nose broke
Flight 3 - Fixed the nose, checked the wires for loose connections, launched. The motor seemed to pull the a/c out of my hand but couldnt manage to make it fly.
Flight 4 - The motor seemed to pull the a/c out of my hand but couldnt manage to make it fly. Crashed and broke the nose completely.

Now I will put the motor in place of the cockpit and fix the cg and try again.
I think a 135W motor is under powered by just a fraction, it would have flied if it was a 180 or 200W motor.

Never the less, lets see what happens after replacing the motor

Finally it flew but not for long, a rogue wind came, the a/c nosedived and the motor's shaft broke.
Which scared the bejesus out of me.
So i am closing this chapter on a the following conclusion that it did FLY.
I am still under the trauma of the broken shaft, thank god i had a bad motor whose shaft i replaced, but it was scary.

I am not too excited because
1.there is no video proof that it flew. the a/c didnt come in the camera's field of view 
2.Trauma of a broken shaft.

Learnt a lot though and that was the the actual reason for the build so i would call it a success.

Congrats!