1moparman1

My Feedback: (28)

Thanks Jeff, sorry but I don't know where is the factory CG at? No manual or marks on my jet
try online to jet ledgend and the manual is no to be found!
Is the CG behind the spar?

Peter

Mark Vandervelden

Its CG as marked by the factory is 110 mm in front of the center of the wing tube, I would recommend 20 mm in front dry.

1moparman1

My Feedback: (28)

Great thanks

dubd

Jeff, In your opinion, what's the minimum runway for comfortably operating the Yak?

jeff sewell

My Feedback: (1)

Hi,
As always it's not the T/O but landing. With a little flap it will get off quick, however, it has the drag of a parachute so slows down quickly for landing - 100m or 300" should do it easily.

Jeff

1moparman1

My Feedback: (28)

Wow! Only need 300' for landings
Mine is super lite and powered by two p100rx looks like I will be landing with 1/2 throttle
Jeff what's your AUW dry?

Peter

dubd

If I got one I'd want to fly it at Tomcats. If it can land in 300', I'll have an extra 100' to spare.

jeff sewell

My Feedback: (1)

My YAK weighed just under 20kg with a single M200XBL... it will actually touch down and rollout in 100ft (if you're good - unlike me!)
Jeff

rchs

Hi Mark, so you suggest 20mm front from the center wing tube is a good CG?

1moparman1

My Feedback: (28)

I am going with mark's 20 mm in front of the middle of the wing tube.
its balanced ready for maiden

rchs

Peter, when do you have plan to maiden? Good luck! Send us video.
I only need to balance and it will be ready.

DrScoles

My Feedback: (18)

Peter, word of caution. The only achilles heal on this plane is the flaps. A few have gone in because of binding or uneven deflection. Lee Seabrook in Australia had only one come down and his skill and the gyro saved it. I videotaped my flaps, they weren't working... LOL They came down right after I touched down and started to slow down. I have 475oz servos on them and I greased and polished the rails to try to make them smooth. I wonder how many people "think" they're flaps are going to full deflection, I proved mine were not.

The speed brake is very effective. I was basically landing without flaps or speed brake and it was fine. Throw on the speed brake and it stops right now. I'm in the mindset that I am not going to use the flaps anymore. Why risk it when I can land it just fine without them? To add a second outboard servo would be torture. I am going to experiment with speed brake and half flaps. See if I notice anything.

Plane is super easy to fly and really has a great presence. I have not flown with all the ordinance yet, that will probably make landings even slower...

1moparman1

My Feedback: (28)

In two weeks if the weather holds

1moparman1

My Feedback: (28)

My flaps seems to go down just fine, I do see it's different by 1 mm on one side to the other on full down. I don't have a gyro on her, since I never flown with a gyro before! I will stick with old school just my fingers ��
Thanks for the info ��

DrScoles

My Feedback: (18)

Just don't put the flaps down the first few times at low altitude... ;-) And don't be afraid to use the speed brake, it rocks.

Mark Vandervelden

Guys this mod for the 1/5th Yak applys to the 1/4th Yak also.

http://www.rcuniverse.com/forum/rc-j...l#post12311858

dubd

I think Mike is saying his and Lee's flaps worked on the ground, but not in the air. Sounds like you haven't flown yours yet?

DrScoles

My Feedback: (18)

In the immortal words of Freddie Mercury and David Bowie.... The flaps don't work.."under pressure." ;-)

1moparman1

My Feedback: (28)

Haha yup not flown yet!
waiting on a good day coming up soon.
so I got it put the flaps down 5 mistakes high lol

DrScoles

My Feedback: (18)

Exactamundo... let us know how it goes!

I maidened with the wing tip missiles, really helped with visibility.

ARA-Jet

My Feedback: (8)

Hello all. I am putting together my 1/4 scale yak. I had a new bifurcated pipe made for it. Putting in a rhino. Does anyone know if the pipe needs to have a certain angle? Any pics anyone can share? Thx

jetnuno

Hi

A Rhino won´t fly this bird..... 17Kg of thrust. The plane at take of will pull more than 25Kg...plus a bifurcated pipe won't help as well

2 x Rhinos will fly it well. I had 2 x Merlin 140 and flew wonderfully till I sold it. This plane as most of exhauts in the under part of the stab will have a upthrust - throtle issue. The exhaust speed under the stab will create a venturi effect that will pull the elevator down, making the tail drop and plane goes up

To overcome this, I would suggest a downthrust angle of at least 5º, up to 8º or more. Also do not use the factory CG-too nose heavy. You can safely go back by 20mm

Good luck

Nuno

ARA-Jet

My Feedback: (8)

Thanks nuno. What throws did you use please?

also how do i get a replacement nose steering arm?

also how do i get a replacement for a broken left main gear bracket? JL does not respond. Sent five emails with no response. They suck...

jetnuno

Hi
I started with factory recomended throws and it worked fine. Just use arround 45% expo on elevator as it is a hige surface and very effective

You can try Jeff at Zedjets based in the UK. I remember that I also had to make a new arm for the nose steering as the original carbon one broke. make one in aluminium. Thre's info in this thread about it. I made an alu one

Thanks

Nuno

VOOODOOO

Hey guys,

I'm reading in this thread for a long time and a lot of information was very helpful throughout the build process of my 1/4 YAK130.
Thx a lot guys!

Last weekend she finally had her maiden flight and I want to share the Video with you guys!
Everything went perfectly and very happy with how it came out!


Thx again guys and always happy landings!
All the best,
Tom from Austria