Hi guys. I'm building a MB339 with a 70N class turbine. The wing span is about 5,5 feet (1,7 mt) and it will weight about 7-8 kg (17 lbs).
In these days i have to choose the right servos for the stabilizer. I will put the servo directly in the stabilizer (one servo for each moving part). I think i will put on , the HITEC hs.5125 digital metal gear servo. It pulls 3,5kg (48.60 oz) at 6V , but the special thing is that this servo is only 10mm thick (3/8 inch).
Do you think this servo could be good for my jet?
This is my first jetplane and i don't have experience about them.
Thanks
Nicola
Italy

P.S. This is the link to the hitec servo
http://www.hitecrcd.com/servos/show?name=HS-5125MG

Nicola,
You don't say what the manufacturer is of your MB339. I have a Modelbau MB339 and a JR DS 3421 servo fits inside the stabilizer quite nicely. It has 75 ozs of torque at 6V.

John S.

John,
I just recently purchased the Modelbau MB 339. Do you have any hints or suggestions?

-SK

SK,
The only major problems I have had with the MB339 is the fuselage to the rear of the wing mount is a little weak. I had an incident that occurred when I supported the plane in a work stand while the engine was still hot from a flight. The fuselage had gotten very soft from the heat and caused the area I mentioned to bend inward slightly. I didn't catch it in time and I ended up with a dent after it cooled.
I solved the problem by adding an additional former of 1/4 ply approximately 6" behind the wing seat. I also applied several generous coats of heat shield and heat blanket with HD aluminum foil to the entire bottom inside length of this area. BTW this all initially occurred in spite of the fact that I had installed a Tam's double wall pipe.

I also thought the method that was utilized for the front wing hold down was too narrow. I added an additional 1/4" ply semi-circle to the original piece to give the hold down more of a safety margin.

The hold down latch on the canopy needs to be beefed up as well. I put 1/4" ply in place of the thinner piece they had supplied for the latch receiver that glues in the front lip of the fuselage opening.

I think these were about all the problems I encountered. The Eurokit gear and brakes fit well and work fine. Watch yourself when using the wheel well template for the wing cut-outs. They have to be positioned very accurately for the gear to retract properly.

Good luck. Don't hesitate to e-mail if you have further questions.

John S.

Hi! Well, it's a Zmodel kit. It's a little smaller than your MB339. I think i will mount this servo , so.
What do you think?

Nicola,
I am not familiar with the Z model kit, but if it is smaller then your 5125 should be fine. I have used many Hitec servos and never had a problem with them.

John S.

I have an original Cermark MB339. Sounds to be about the same size as yours. Mine flew origianlly with a Ram 500, now with Jetcat P80. I have Futaba 9202's on everything (elev, rud, flaps, and ail's) with no problems at all. Everything is still tight after all these years

Do you still have the Modelbau MB 339 kit? if it is untouched in white gel coat and still in the box I would like to purchase it from you, you can Email me at: [email protected] or you can call me at my cell:914 438 4041
thanks
Tony

I am looking for a Model-bau USA MB 339 kit in white still in the box please Email me at [email protected] or call at 914 438 4041.
Thanks
tony

Sorry Tony. I no longer have the plane. It blew up in mid-air at the Fentress Jet Rally a couple of years ago.
-SK