Good afternoon
I got one last depron sheet left before i leave for my college, so i decided to make one more a/c.
I had lots of options, SEPECAT Jaguar, PAK-FA, JSF, etc.
Since i had only one sheet left so i took the safer route and decided to make a F22

Since it is not an exact replica, i am taking the liberty to call it YF-22  

The whole project was supposed to start on 18july but i couldnt resist so i started building the a/c my way. I seriously feel that F22 even though is a wonderful a/c to build, it has become quite a cliche, so keeping that thought aside i started building one.

Electronics are the same as always except the motor
Motor : Aeolian C2822-KV1200
ESC   : RCFORALL DY 18 AMP ESC
Battery : RCFORALL 11.1V 1000 mah
Servos 2 nos : RCFORALL DY 0204 : 9 gms

X- Motor mount from RCBazaar.
Prop : 8x6 EF
Depron: 12mm (that i got from Mr Dhiraj)
Adhesive:5min Epoxy and Double sided tape

The major problem i faced last time were the vibrations, so i decided to buy a good motor mount and not make one myself.

waiting for some pictures....

The actual build will start on 17th july, so till then i decided to make a mockup using standard cardboard to decide what to cut and where to cut.

My maxim is not to use plans so i only used the blueprints available online, scaled to my use and drew on cardboard and cut

Pic 1 : Shows the belly of the wing, with the desired position of the prop. The brown tape holds the air intake and the white tape helps me decide the contour of the fueslage.

Pic 2 : Shows the silhouette of the prop, expected CG, side panel of fuselage and the expected height of the motor mount.

Pic 3 : Shows the completed section of the fuselage. The bottom will have an opening for repairs.

Pic 4 : Shows the position of the vertical stabliser.

Pic 5 : Shows the position of all electronics.

Pic 6 : Shows the position of all electronics. another angle, the nose will be made of layers of depron and will support the base of the fuse and maintain proper distance between the wing and bottom of the fuselage.

Pic 7 : Shows the bottom and the open air intakes as opposed to the first design, because a closed intake would become a bluff body.

Pic 8 : Shows the Rear of the the aircraft. It has an opening. The reason for that is that if it had been closed then the air sucked in by the prop though the intakes would get stuck in the closed rear section and would affect the structural integrity of the a/c. The opening can also act as a nozzle and increase the velocity of the air coming out

Depron build will be done after 18th July

how did you select his motor
what is he AUG

you need a higher RPM and a small prop

You choice of 1200kv motor and 8x6 prop is not a standard config for a Pusher Jet. Go for a 2200Kv motor with a 6x4 sports prop.
Is that material Biofoam ?

If you have not frozen the plan, I would rather suggest you to religiously follow the F-22 plan by RcPowers.com or  even better http://rc.tomhe.net/f-22

I chose this motor because i have built two a/c having similar dimensions and they have flown very well, another reason i got this motor is because it has greater thrust than the other configuration.

Thank you for the plans, but i'd rather make my own because i enjoy building more than flying.

I do not want to spend anymore on electronics for the time being, thats why i am not changing the motor.

I do intend to buy http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=100_93&products_id=760 that is EMAX CF2805, someday.

I'll still try with the current configuration first. If i run into problems, i will then post and diagnose accordingly.

Weight as of now im not aware because i still need to get the motor and the mount.

what material is this, to me i seems like some kind of hardbord or something like that, i may be wrong.

all the best!!!!

cheers
Ashish

the material is the cheap cardboard. I only used it so that i could make templates for converting to depron. This model is not meant to fly, its only for getting the ratios and the feel of the aircraft and to find the design problems which i may face if i work on depron directly.
The main reason i did this was because i was getting anxious to start but i couldnt start before 18thjuly, and the major problem with such scratch builds is that some problems cant be visualized until they are actually faced with no matter how good one can visualize.

@ashish - thank you sir, i am really gonna need it as i always do.

I was having some concerns about the CG of the a/c so i decided to calculate it myself.
Earlier i had assumed it but i wanted to be sure, so i did research and calculated it myself.
As it turns out i was pretty close but not good enough.
Pic "F-22 cg 2": Shows the calculation of the CG.
Now with reference to "Pic 5" I will move everything towards the rear by a few inches to get the CG right.

Hey, using cardboard templates seems like a good idea!

Quote from: naatumach on July 01, 2011, 12:08:23 AM
... so i did research and calculated it myself.
...

How exactly did you do that? Any set of formulae?

the new cg too is too far forward. cg aft of 20% mid chord is the right place to start with, your nose is too short thats why the problem, should have gone with the janes pic. plan view, all the best, at the outset i can tell you , it may not fly well,  , prove me wong

How much did the depron cost you per sheet? And what was the shipping cost and time?

Depron were 12mm sheets, quantity 4
Total cost= 880+760(shipping)+30(bank trans. Charges) =1670
I paid on 8thJun, He dispatched on 8thJun and i got it on 13thJun
Dtdc tracking id D05776318

Hmm...that's a bit costly. The base price is okay but the shipping charges seem too much. I'm gonna see if it's available locally.

@augustinev :
Sir i dont want plans, there is no fun for me to build from plans.
Your skepticism fascinates me, now i am all the more excited to do the build (not to prove you wrong), but to see it first hand what the problem looks like.
I am only here to see how and why they fly.
And even if it crashes, i will still have the comfort of saying that i built it.
Thank you for your diagnosis, would you please elaborate the nature of problems i may face.
The only point of worry is that chennai is too windy and not only that there are cross winds and the runway is either too windy or there is flying going on or its night when the flying has stopped.

@Swapnil:
Yes the shipping costs are steep. I tried to ship my own depron from dehradun to chennai once during my semester vacations and the shipping came to Rs.1000. Its all about the volumetric weight.
It is always better to find it locally but dehradun is a dump , so i hv settled with dhiraj.

Step 1. Extrapolate the leading edge and the trailing edge.
Step 2. Draw the major chord(red)  on either side of the minor chord(green)
Step 3. Draw the minor chord(green)  on either side of the major chord(red)
Step 4. Join the extended chords diagonally
Point of intersection is the MAC
Step 5. Extrapolate the MAC point towards the leading edge
Step 6. take its projection on the center line of the a/c.

Correction : MAC is not a point it is a chord.
Correction : Step six is incorrect

Cool!!! 
Thanks man! 
I got a couple of books on aeronautical engg. but never opened them. 

Good Luck with your plane!

Hey, check this out:
http://www.rcindia.org/for-sale/depronbiofoam-for-sale-(5mm-only)/msg32324/#msg32324

At the given rates you could have got your depron sheets for 653!

LOL. I also "should" get in the habit of reading books.

foamybuilder is sending by indian postal service. thats why naa (i guess).
What would you prefer indian postal service or dtdc? Its depron what if it gets manhandled?
dtdc can also manhandle it.
Check out
Check reply #17's http://www.rcindia.org/for-sale/depronbiofoam-for-sale-%285mm-only%29/msg32324/#msg32324 pdf
it says Volumetric Weight (in kg) = (Volume in cm3) ÷ 6000

Dtdc also says in http://www.dtdc.in/subpages/services/Volumtric_Weight.html
VOLUMETRIC WEIGHT(AIR) = LENGTH (IN CMS) X WIDTH (IN CMS) X HEIGHT (IN CMS) / 6000

Now all that needs to be done is to tally the postage charges for which i was charged and the postage charge according to the formula

Go through the whole thread, people who bought it seem satisfied...

thats good to know people are satisfied.
Next time i will ask for complete shipping details.