RC India

RC Models => Electric Planes => Topic started by: Samanth on May 12, 2011, 10:06:00 AM



Title: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 10:06:00 AM
Hey guys,
This is the JAS-39 Gripen I built. I was originally looking for Eurofighter Typhoon plans but I ended up choosing the Gripen  :P
Spent about 8 working hours on it. It was 100% RTF on 24th april, 2011. I have not yet maiden'd it. Its the first canard , delta winged plane I have ever built.

Materials used -
  • 6mm AeroDepron from rcfoam.com
  • 6mm Carbon Rods
  • 4mm Balsa
  • 8mm Balsa (for missile rails)
  • Acrylic Paints
  • Velcro
  • Hard wood (for motor)
  • 5-min Epoxy
  • Super Glue (feviquick)
  • Hot Glue(glue gun)
[/i]

Tools -
  • Scalpel with #11 blades
  • Heat Gun
  • Dremel Glue Gun
  • Dremel 4000
  • 150grit Sandpaper
  • 320grit Sandpaper
  • Homemade Foam Hotwire cutter
  • Pliers, Wirecutters, etc

Electronics/Misc -
  • 3x digital metal gear Servos from HK(elevons + Canard)
  • 1x Standard Servo (Rudder)
  • 2200kv Brushless Outrunner Motor
  • 45amp ESC
  • BEC which I made on my own (LM7805, IN4001, 3300uF 25v Capacitor) + heatsink
  • APC 10x7E prop.
  • 3S 1500mAh 30C Lipo
  • AR6200 DSM2 Rx + Remote/Satellite Rx
  • Spektrum DX6i

Pictures
(http://i1176.photobucket.com/albums/x327/samanthmottera/12.jpg)
(http://i1176.photobucket.com/albums/x327/samanthmottera/7.jpg)
(http://i1176.photobucket.com/albums/x327/samanthmottera/25.jpg)
(http://i1176.photobucket.com/albums/x327/samanthmottera/21.jpg)
 
Hows it ? please tell me what you think about it ! :D
Thank you ! :)



Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 10:11:12 AM
For more pics -
http://s1176.photobucket.com/albums/x327/samanthmottera/ (http://s1176.photobucket.com/albums/x327/samanthmottera/)


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: sundaram on May 12, 2011, 10:15:18 AM
 :goodjob: It is a great job. Steve Shumate plans are awesome

I would only request you to change the props to 6x4 / 7x3 or change the LIPO to 2S or you change motor with 1000-1400 KV with the same set up.


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: SunLikeStar on May 12, 2011, 10:26:10 AM
Very clean build, it amazing what could be done with foam {:)}
I don't know which motor you are using, but 10x7 on 2200kv are you sure the motor can take this. If it can then calling it a rocket will be an understatement :P


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 10:30:42 AM
Thank you Sundaramvelar and SunLikeStar :D

I forgot to mention that this is the 120% version of the original design

The prop and motor combo is correct, i tested it with a grip at CG and 30% throttle. I could feel it trying to jump of My hand. Imagine at 100% throttle !! :D :D
Yes and i have observed that the motor gets a little hot, but it wont be a problem once its airbone, i suppose.  


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: PankajC on May 12, 2011, 10:52:01 AM
Samanth,
Its a beautiful build well done and look forward to the maiden experience.

It just might be a good idea to do a 10sec test on full load with a watt meter. just assuming that it will be OK once airborne is not good enough

Pankaj


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 10:58:16 AM
Thank you Pankaj ! :D
I'll keep that in mind.

Yes.. I think its about time since I bought a watt meter...


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: VC on May 12, 2011, 11:04:40 AM
Beautiful model, very neat build! Waiting for the maiden................... :thumbsup:


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 11:07:00 AM
Beautiful model, very neat build! Waiting for the maiden................... :thumbsup:

Thank you soo much :)


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: foamybuilder on May 12, 2011, 11:10:31 AM
Model looks awesome  :thumbsup:


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: ashJR7202 on May 12, 2011, 11:24:24 AM
hey its really nice & clean build!!!!!

2200 Kv motor with 10" prop, hope it will not oveload the motor!!!!!!

what motor are u using??


all the best for maiden!!!!

cheers
Ashish


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 11:26:37 AM
Model looks awesome  :thumbsup:
Thank you !! :)


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 11:28:21 AM
hey its really nice & clean build!!!!!
2200 Kv motor with 10" prop, hope it will not oveload the motor!!!!!!
what motor are u using??

Thank you Ashish :)  Yea, even I hope it wont overload the motor or torque roll the aircraft.


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: anwar on May 12, 2011, 11:33:44 AM
10" props are sort of the upper limit on many motors that are close to 1000KV range... you should really take the help of someone with a wattmeter in testing it out. 

Chances of the prop hitting the ground during landing are also quite significant (unless you land in a good amount of grass).


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: ujjwaana on May 12, 2011, 11:58:07 AM
2200 Kv motor with 10" prop, hope it will not oveload the motor!!!!!!

As a thumb rule, a 6x4 Sports prop is max you can put on normal 2200kv motors on 3S. With 2S, may be 7x4 (not confirmed). 10x7 is way overkill for the motor. Isn't it the same sold by RCforall/RC-Timer one ? I have that at max it can sustain on 6x4 is 22Amp. Putting a 10x4 would Quadruple the Amp usage to 100Amp range, just too, too much for the little motor.

I have a Wattmeter with me which you can use to confirm popular opinion.


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 10:47:59 PM
Putting a 10x4 would Quadruple the Amp usage to 100Amp range, just too, too much for the little motor.

For the wingspan, I need to use atleast a 9x6 Prop. What motor do you recommend ?


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: VC on May 12, 2011, 11:28:13 PM
Just a question, how did you get the Aerodepron from Rcfoam.com into India?


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: ashJR7202 on May 12, 2011, 11:30:02 PM
if ur using 2212/06, then dont use prop bigger than 6x4...

u can also try using 2218 with 6x4 more punch to ur fighter, but with 45A ESC, i recently tried this on 24" Eurofighter with Canards, and it was climbing vertically at 3/4th throttle!!!!!



Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: jits on May 12, 2011, 11:35:05 PM
I too have the same question that VC has......does rcfoam do int. shipping of foam sheets......is it reliable?


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 11:45:28 PM
Just a question, how did you get the Aerodepron from Rcfoam.com into India?

rcfoam.com ships to India. I received mine in just 8 business days since I ordered it ! :) Aerodepron is 20% lighter than white depron and even more lighter than grey depron with the same durability.

I too have the same question that VC has......does rcfoam do int. shipping of foam sheets......is it reliable?

Yes its quite reliable. I ordered 10 sheets of 6mm aerodepron (i forgot the size). They give you a tracking number and is shipped via USPS Priority Mail International. The item didnt even get stuck and customs with absolutely no customs charges :)


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 12, 2011, 11:46:53 PM
if ur using 2212/06, then dont use prop bigger than 6x4...

u can also try using 2218 with 6x4 more punch to ur fighter, but with 45A ESC, i recently tried this on 24" Eurofighter with Canards, and it was climbing vertically at 3/4th throttle!!!!!



Wow awesome... !! :thumbsup:
I really need to do more research..!


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: warriornair on May 13, 2011, 12:24:47 AM
good work samanth, what kind of paint did u used ?


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: jits on May 13, 2011, 01:23:57 AM
just tried an order of 10 sheets...the shipping cost comes to $46 !

anyways....some real hard work gone in yr scratch build ....great work !


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 13, 2011, 08:20:55 AM
good work samanth, what kind of paint did u used ?


I just used locally available acrylic paints. Rs.15 for each bottle :P


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: Samanth on May 13, 2011, 08:27:57 AM
just tried an order of 10 sheets...the shipping cost comes to $46 !

anyways....some real hard work gone in yr scratch build ....great work !

Remember : shipping costs are greater not because of its weight, but because of the VOLUME. Order smaller sheets(10 sheets) and your shipping should be near $29.00....... if you order even 3 sheets of large size, then its going to be $46.


Title: Re: Scratchbuilt : JAS-39 Gripen , plans by Jetset44(Steve Shumate)
Post by: rcpilotacro on May 13, 2011, 01:27:57 PM
Samanth,

1. if you are going to use canard control you need to reinforce it from the inside, with a piece of balsa may be.
2. be careful of canard, be critical on its rigging and have a mechanism to adjust it (Both port and stbd individually).
3. be ready for canard interference, it can be tricky in turn, if canard stalls before mainplane controllabilty will be lost. therefore canard has got to be rigged at less alpha than the mainplane,
4. if it is going to be moving canard, keep its throw less initially.
5. is your stbd canard fowling with the fuse ? recheck. prevent canard lateral movement, somehow
6. fly it stock, colour and sticker can follow. with a magnifying glass check the aerodynamic , thrust requirements of the plane,

all the best