afterburner

My Feedback: (18)

The wall thickness I'm reading is .060". I can't help you with the type. Sorry.

Marty

mikedenilin

My Feedback: (67)

Hi Maj. Woody,

Here are some photos of your L39 at Kentucky Jets. Not bad for logging 43 flights in a jet event with 3 planes. Enjoy.

Mike

MaJ. Woody

My Feedback: (28)

Thanks Mike!
I am at Jets Over The Vally right now with my L-39. I logged six flights on it yesterday and am headed out to the field now. My new Futaba 12Z is AMAZING!!!!
See Ya soon.......

RemoteJets

Hye There L39 flyers,

one small quistion.

Will a old gasstart P120 be to big for this FeiBao L39?

Otherwise it must be a Jet Legend L39 but then the P120 is on the downside of the airplane.
And I like to be on the upside [8D]

Thanks for your anwsers.

Greetz,
Berto.

rcjets_63

My Feedback: (4)

Berto,

A P-120 (even an old one) will turn the FB L-39 (length 75" WS 58") into a rocket and the weight of the engine and more fuel will certainly make it heavy. Dom's is perfect with a P-70.

The JetLegend L-39 (length 95" WS 74") is bigger and seems better suited for a Titan. A Skymaster L-39 (length 86" WS 68") is the right size for a P-120.

Regards,

Jim

RemoteJets

Mhhh, the weight wouldn`t be a big diference.

The P80 weights only 60 grams lighter then a P120, but lets take it a little bigger and let`s say the diference is 100 gram.
I don`t think the plane will feel that.

How much fuel does the L-39 carry now?

My PA F-15 has 4 ltr of fuel on board, weights 13,5kg wet and I use 3 ltr of fuel for every 6 to 7 minutes of flight.

With a smaller plane I can fly more half gas and burn less fuel



I`ve the JL L-39 seen fly with a 160.

And I think the 120 will fly, and will fly good but for vertical power and short fields (my home base has max 100 mtr of grass) the 120 will not be sufficent I guess.

And the JL is a lot more expensive (but also a lot bigger).

Mhhhhh.

MaJ. Woody

My Feedback: (28)

The P-120 will be too large. I really do not think it will fit without cutting away bulkheads and such. You dont want to do that as you will weaken the airframe. Mine is already a rocket with a P-70.....189 mph straight and level and no wind. Fuel consumption will be another issue. The tank is 70 ounces. I added another 12 ounce tank for a total of 87 ounces. I only get a 5.5 minute flight with enough reserve for one go around. Get a bigger airframe for your 120.

RemoteJets

That`s clear.

Thanks.

Mhhh, gonna look for something else [8D]

GRt,
Berto.

Olafsson

Hi
I´m new in the tread,I love well powered planes, I hade the Skymaster L 39 with 12kg thrust turbine and it was too litlle power for mi taste. I love the L-39 and I have 3 sizes, The Savex smal one with 7,5kg turbine , Skymaster L-39 with Hawk 190R , that is a perfect mach and I fly over 10 min on 2,8 l of fuel, I hade a fly Eagle jet L-39 also but that airframe was soo heavy ( 7,5kg plane and gears , nothing else), 12,7 kg fully loaded, flew nice with Hawk 100R but the landing was tricky, had the balloning experience like Woody describes. I crachet that jet early this summer in a landing. Now I have received the FBjet L-39. I will putt in mi Hawk 100R that gives almoste 12kg of thrust and I belive that vill be a perfect mach as I can fly on 2l of fuel for 10min with that turbine. I have noticed that L-39 is not that Weight sensitive, so I have to say that the P 120 will be good choise except for the fuel consumption. but I have read that some have 1,5 l smoke tank in FB L-39 so I belive that the plane can take that extra weight OK. I aim for start weight of around 10 kg , as that smaler L-39 flew ok at 12,7 kg i belive this will be a nice plane to fly. I have also the new version and I will put out some pictures how I will solve the elevator servos problem. I have some ideas.

By the way I have a friend that explained that with exthouste tube, the tube have to be calculated for the turbine , air intakes area and prefered airspeed in order to get a good instalation, A too large tube will also generate higher temp in the fuselage.

I hope that Woody will sum up his experience and make a landing manual for the L-39 as the is the only tricky ponint for the L-39.

Best Regards Tomas Sweden

RemoteJets

Hye Tomas,

that are some interesting thoughts.

Mhhh, who nows in the future......

and instead of a smoker tank some extra fuel is always a good deal.
On the other hand the P120 will push a little to much on idle so it will fly over our comlete 100 mtr field before touchdown, that`s something I don`t want.

But the power/weigth ratio will be nice


Please update us with your modifications.

Grt,
Berto.

tasma88

Hi
I am new in the forum and at the present I am in the building process of this baby FB L39 . I will be using G booster 90 from evojet .what do you thing about the thrust tube and the fuel tank provide by the kit for this engine

Regards tasmar88

mdeseve

My Feedback: (1)

The thrust tube is ok, i have a rabbit in it and it fit fine.

rickj202

My Feedback: (37)

What does everyone recommend for servos on the FB L-39? I am not sure if this has been covered before.

RIck

MaJ. Woody

My Feedback: (28)

My L-39 was an earlier design and has the elevator servos in the fuse instead of the tail like the new version. The newer version will probably not accept a standard size servo.

Here is what is in mine:

Futaba 3305 ~ nose wheel (Any standard size or mini high tork Analog metal gear servo will work)

Futaba 3305 ~ retract (Any standard size or mini Analog servo will work)

Hitech 425BB ~ brake (any standard or mini Analog servo will do here)

Futaba 3050 digital ~ 2 for ailerons (Any standard size or mini high tork Digital metal gear servo will work)

Futaba 3050 digital ~ 2 for elevators (Any standard size or mini high tork Digital metal gear servo will work)

Jr 3421 ~ rudder (Any mini high tork Digital metal gear servo will work)

Hitec 645MG ~ 2 for flaps (Any standard size or mini high tork Analog metal gear servo will work)

afterburner

My Feedback: (18)

Dom is correct about the newer version stab. It is setup for minis. I'm still working on my L-39 but using this thread and Dom's good info I decided to make servo mounts like the older version and have the servos alongside the turbine. The main reason for this was that Dom said he needed a fair amount of weight up front to get the CG right so putting two servos all the way back didn't seem like a good idea. I have not finished the pushrod setup for the elevators but due to the angles involved, you will need ball ends on both ends. I have installed all the other servos and was able to use full size servos on all the control surfaces including the rudder. It was worth the small amount of extra weight for my peace of mind to have 340 in. oz.(Futaba 9156) on everything. Overkill, I know.

Marty

rhklenke

My Feedback: (24)

I don't think its overkill at all Marty. Personally, I'm not going to use anything but full-size servos (JR 8411, 8611, or 8711 in my case) on any of the primary flight controls of my jets anymore (with the *possible* exception of the rudder). I've had too many problems with mini-servos and I'd never trust them on the elevator of a jet. YMMV...

Bob

MaJ. Woody

My Feedback: (28)

I have 158 Total Flights on my L-39 now. I can't wait to hit 200!!

frizlot

Hi Dom

Great thread - Well done and big thanks for all the effort !!

I just ordered one of these and will start building soon as it arrives and will be using a K80 in it - Could you possibly give us a break down on all travels ect for a maiden. I realize that all aircraft need fine tuning, but you seem to have your pretty well set up and this would be a great starting point for new one - We are flying at about 4500 ft, would you change anything ?

Cheers Jack

MaJ. Woody

My Feedback: (28)

Thanks Jack!!

kingair41

My Feedback: (13)

I use a K80 in mine and it does fine on grass. 250-300 feet is the norm. In flight 1/2 throttle is fine for 6.5 minutes with stock fuel tanks. You'll love this jet as it has no bad habits....

Doane

frizlot

Reading all this thread really gest one excited about this jet - I am really looking forward to the project ! King what is you set up. CG - elevator flap and aileron movments. How much elevator compensation have you dialed in with flaps.

Cheers

Jack

frizlot

Looking at the new config of the horizontal stab - looks like the JR DS3301 will drop right in for the elevators, but its only a 4kg and has plastic gears. Do you guys think its enough ?

Regards

Jack

frizlot

Hi Doane

Looks like you have the new kit with 1piece H - stab. I notice these newer ones don't have the former at the back to support the pipe. Can you tell me what you did here. How does it fly with the K80 I am thinking of putting one in mine.

Regards

Jack

tasma88

hi did you finaly set up stab servo mounts like the older version and have the servos alongside the turbine?if yes can you give me some informatiom or pictures

afterburner

My Feedback: (18)

Yes, I set it up like the older version. I used ball links on both ends as it's not a straight run from the servo to the horn. On the older version, the horns at the elevators were wider apart as designed to line up better with the servo arms. On the new version the horns sit much closer together above the center of the pipe. I used central hobbies 4-40 titanium rod ends with the carbon fiber rod and then slipped that into an aluminum rod to reflect heat and stiffen it up a bit more. If I was to do it again, I would use 6-32 instead of 4-40. The plane has not flown yet. Its about 95% done.

Marty