stunthanger.com

Design => Stunt design => Topic started by: Dwayne on May 05, 2013, 09:20:53 AM

Title: Twin 19?
Post by: Dwayne on May 05, 2013, 09:20:53 AM
Hi all. A R/C friend of mine just gave me 2 NIB Fuji 19 C/L engines, I have one allready and they are good little engines. So I'm going to design a twin for them, what do you think a good wing area would be for them, I'm thinking around 520 sq in.
Thanks for the help
Dwayne
Title: Re: Twin 19?
Post by: Paul Smith on May 05, 2013, 12:15:08 PM
I might go a little bigger.  Two 19's with all the support equipment weigh more and make more power than a .38.
Title: Re: Twin 19?
Post by: Dwayne on May 05, 2013, 04:15:29 PM
I might go a little bigger.  Two 19's with all the support equipment weigh more and make more power than a .38.

Yeah I really didn't wrap my mind around that. I just weighed the engines and with out mufflers they are 12.5 oz. That's a ST 60! Yikes ~^ So what ever I decide it has to be light. I'm thinking a Legacy 40 wing(565sq) and a built up profile fuse using 1/16th balsa sides, 3/8 balsa and 1/32 ply doubler nacelles.
Title: Re: Twin 19?
Post by: Air Ministry . on May 06, 2013, 07:33:15 PM
These suckers use a Oriental Wing , 48 in x 8 in. .

(http://www.controlline.org.uk/userupload/613/0004.jpg)

(http://www.controlline.org.uk/userupload/613/0003.jpg)

Now for the Lecture .  8) Thrust lines equidistant from fuse c/l .
Original Whirlwind in 74 was 36 Oz. 262 38 / 40 with mufflers .
Parental Advice was " Youll put the mufflers on that " . LL~

These suckers are around 60 Oz , but 262 is 72  %^@
so 70 ft of .018 is necessary for the Schedule . & bigger tanks ,
if you want all the level laps . 80 ft lines'd be better . 8)

(http://controlline.org.uk/phpBB2/userpix/98_vets_2013009_1.jpg)

No Worries . If you conserve momentum , rounds & wingovers o.k. on outer .
But it IS a Flying Wing Fence .  :!
(http://www.controlline.org.uk/userupload/613/0005.jpg)
A 60 Oz Mk 11 Meteor I did , on 60 ft Sig. 015s WASNT a good Idea .
58 in long fuse , six or eight ( or nine at Canopy ? ) deep , had ' elasticity '
in the wires & 1/4 loop control delay .Unless you ran at the Airspeed .  LL~

(http://controlline.org.uk/phpBB2/userpix/98_vets_2013003_1.jpg)

These Jets have Limited Fuel Range .  n~ gliding in after a quick scedule last Saturday .

(http://controlline.org.uk/phpBB2/userpix/98_vets_2013010_1.jpg)

the two 25s are adequate . Original on OS max 20s at 38 Oz , would wingover & inner / outer
Loop on outer engine , muffled . on straight ( no Nitro ) fuel . Usually flow on .015 x 60 ft ,
or .012 x 70 ft , if flat calm & engine runs checked . Overspeeding on those lines wouldve
meant free flight .
Title: Re: Twin 19?
Post by: Dwayne on May 08, 2013, 06:00:31 AM
Hey Matt thank you very much.
Title: Re: Twin 19?
Post by: Timothy Payne on May 09, 2013, 04:19:53 AM
I'm using a pair of PAW 149s in my next build, mainly because they're light (3.5oz), reliable, and parts are readily available over here in the UK. - You should bear mind the power to weight ratio of your model. Remember biggest isn't always best! (My first RC trainer said "for 1-1.5cc engines". I ended up using a PAW 249 and it flew like a Mustang!;-)

(Nice Mosquito by the way)