SkyKnight

My Feedback: (67)

I'm putting the final touches on this MB339 but I don't have the CG location. It was purchased used. I tried to contact Modellbau-USA but the phone number goes straight to a busy signal. I sent email but no reply. Wing Span = 75" Fuse length = 73". Oh I almost forgot........control throw deflection would help too! If anyone knows who the manufacturer is I might be able to get a clear canopy too. This plane has a fiberglass wing and no engine hatch. The engine is only accessable by wing removal. That 's not a problem for me though.

I will appreciate any help.
-SK

NICLAS

I have flown MB339 from Graupner for 2-years and what i remember is that graupner want the CG behind the main gear!!!!!
But I have mine just in front of the gear and that have worked perfect

NICLAS

I think the Modellbau and Graupner are the same

cel

Hello. I have the manual and center of gravity is 195 mm from the leading edge of the wing measured back. Do you have pictures of yours ?. Regards.

SkyKnight

My Feedback: (67)

I can take pix if you like. I just received a manual form Modellbau-USA which has that info as you described. This is where my confusion comes in....when the wing is attached to the plane, the is an area of about 1/2" between the fuse and the inlets which may qualifyu as the beginning of the leading edge of the wing. Measured back from there puts the CG location just in front of the main gear. If I move to the other side of the inlet where it is obvious that the wing's leading edge begins, the CG location will be placed behind the gear. I didn't measure that yet. I was waiting to collect more info from this thread. Can you clarify this?

Thanx

cel

Hello. I did not start working on my airplane yet. A friend of mine has logged several flights on his MB 339. I will try to get its CG. position. Regards.

SkyKnight

My Feedback: (67)

OK Thanx! Standing by.............

BlackCloud

My Feedback: (12)

Since Modelbau-USA is around the corner here from the field we have had many fly the 339 at the field. The CG was set by using a digital postal scale under the nosewheel with the mains on blocks of eequal height to the scale. The weight would be shifted until the digital scale showed exactly 2.0 pounds. This was found to be the optimal setting to reduce the aermacchi bounce syndrome on landing.
I am pretty sure that was with the UAT full and tanks empty. I will ask some friends that fly them the most and get back to you on it.
The main person has been extremely busy with other work projects and some other issues but I have been told things will get back to normal soon to attend to the modeling business. If you are still looking for the canopy send me a PM and I can ask for you when I see Alberto, which may be tomorrow morning since we have a big jet fly this weekend.
The Modelbau-USA Aermacchi as wll as the Storm are made by Gustavo Campana in Argentina if my memory is correct.
Mark

SkyKnight

My Feedback: (67)

So does this mean it is not a Graupner kit? Mine has a composite one piece wing.

Thanx for the info Mark! I'll try that balance technique.

BlackCloud

My Feedback: (12)

I just confirmed with my friend that has put together 8 of them. 2 pounds showing on the scale under the nose wheel with the UAT full, tanks empty, airplane level (thats with the blocks under the mains so it it the same height as the scale, doesn't have to be exact just close to same height) They would always borrow my scale until I got them one of their own. It is a digital scale from Sam's Club in the office supply aisle and costs just under $50. As long as you have a decent scale you
I asked about any canopies lying around, nothing came to mind but he will check and let me know if he comes up with one.
It is not a Graupner, more like a clone. I have seen them fly on 500s as wells as 750s and even a 900 which was way way overkil.
Most flew on the 750s which is still overpowered and with the 500 it flew every bit as good that you couldn't tell it was only a 500 in it when it was flying. Basically any engine from 14-24 pounds is best for it.
Mark

SkyKnight

My Feedback: (67)

Kewl !! I'll get a hold of a scale and get the balancing act going on. This is a good example of the benefit of RCU when you can query forums for info. Thanx for your research.

I stuck a P120 inside for the kero-start option since it doesn't have a canopy but it is limited to 117K to keep from tearing the wings off. I'll keep ya posted on my progress. I expect this to be a good "pocket jet" as we call them.

ttyl,
-SK

hcuellart

My Feedback: (41)

Hello guys I am beginning to assemble this ARF and don't know exactly how to hold the canopy... I would also like to see how you guys installed your electronics, as this will be my first turbine, I am a bit in the air with the installation...
Pics would be greatly appreciated!!!
Thanks for your input
Homero

SkyKnight

My Feedback: (67)

Homero,
I haven't had the chance to fly mine yet. This weekend is out too due to weather. I'll get some pix together sometime this weekend since the weather report is calling for some shop time.

All of my equipment is on the radio tray and my batteries (ECU & RX) are in the front of the nose, the section in front of the nose gear.

Stay tuned.....

hcuellart

My Feedback: (41)

Great SK, I'll be anxiously waiting!!

SkyKnight

My Feedback: (67)

Here ya go Homero! I hope you can find what you are looking for. I flew mine today. Balanced at 2.0lbs on the nose wheel worked perfectly. The plane is super smooth and really quiet. It actually sounds like an airliner when it comes past ya. We are looking for another one if anybody wants to let one go! Hope the pix help. OMT....my installation is setup for JetCat kero start. Note the two valves behind the ECU.

-SK

BlackCloud

My Feedback: (12)

Glad you got it up and running

SkyKnight

My Feedback: (67)

Yep! All went well and thanx for your input. I''m very impressed with the new kero start plug also! Start up was noticably quicker and I only used 340mah s. Post flight inspection found a small leak in the vent fitting on top of the fuel tank and I have a concern about the horizontal stab. It doesn''t appear to be solid or very rigid. Idon''t remember noticing this during assembly. The seller had a hand written note on the cover of the manual that a different spar coupler was to arrive later but it never showed up. I sent him email and left voice mail but he is not returning any calls. Has anybody else notice this condition or experienced any problems? Is there a fix other than permanently mounting it with epoxy?

I''m waiting for a response from Alberto now about purchasing another one. Another buddy of mine is interested in one.

-SK

hcuellart

My Feedback: (41)

Hello SK I've been out for a couple of weeks. The pics are excellent but I still don't get it on how to install the canopy The picture of the latch you are using is not very clear (well at least to me)... Again thanks for the pictures and congratulations on the maiden flight!!
Regards,
Homero

SkyKnight

My Feedback: (67)

OK. There is a piece of inner ny-rod, the yellow part, that is glued in from the point of the nose to the opening of the canopy. At the opening, there is a small piece of wood used to mount the ny-rod "guide" at the proper position to allow the wire that will be inside the guide, to insert into the framing of the canopy. The canopy is held in place at the rear by the canopy framework and secured in place by the wire inserted through the ny-rod into the front canopy frame. I'll try to get a better pic for you this weekend.

-SK

SkyKnight

My Feedback: (67)

See if this helps make a lil more sense Homero. You can see the piano wire in the front of the nose as well as inside he fusein the locking position. The other pix a just different shots of the wire as it would extend into the lp of the canopy. I'm bad at explaining myself so I hope this makes better sense for ya.
-SK

hcuellart

My Feedback: (41)

Got it, I think I know how it goes... Thanks SK!!

LittlePilot

My Feedback: (2)

SkyKnight,

How long you can fly with p120 in your MB339? How does the vertical climb? I bet it was awesome.