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-   -   JMB MB339 composite 1:6 PNP (https://www.rcuniverse.com/forum/rc-jets-120/11694162-jmb-mb339-composite-1-6-pnp.html)

dr.tom 10-15-2021 10:17 PM

JMB MB339 composite 1:6 PNP
 
JMB MB339 is a small full composite/airex jet with awesome flight qualities
and the best it comes in PNP all ready installed , servos MG Digital, electric retracts, door servos, pipe, tank UAT

you need only to install your engine and receiver
New V3 (metal control horns,servo arms, ball links, rigid round UAT, lighter tail section so without factory glued 180g ballast lead in the nose cone)

Length 1850mm
Wingspan 1790mm
Dry weight all installed 7,8kg

4 colour schemes (tricolori/blue, swiss/white-red, silver camo, saudi arabia/brown camo)

For Engines like K60, K70 K85 - k100 for speed junkies


https://cimg0.ibsrv.net/gimg/www.rcu...b1ac35b682.jpghttps://cimg4.ibsrv.net/gimg/www.rcu...acd0696e5e.jpg
https://cimg1.ibsrv.net/gimg/www.rcu...c44bf3e1b0.jpg
https://cimg2.ibsrv.net/gimg/www.rcu...87990a4b16.jpg
https://cimg3.ibsrv.net/gimg/www.rcu...cb871cd7f0.jpg
https://cimg4.ibsrv.net/gimg/www.rcu...dc00a6c91a.jpg
https://cimg5.ibsrv.net/gimg/www.rcu...10fe2e6184.jpg
https://cimg6.ibsrv.net/gimg/www.rcu...8a79b29194.jpg
https://cimg7.ibsrv.net/gimg/www.rcu...ea02008c2d.jpg
https://cimg8.ibsrv.net/gimg/www.rcu...8cb1fd47f1.jpg
https://cimg9.ibsrv.net/gimg/www.rcu...537b5bb611.jpg
https://cimg0.ibsrv.net/gimg/www.rcu...d99b70a51e.jpg


dr.tom 10-15-2021 10:19 PM


dr.tom 10-19-2021 01:00 PM


dr.tom 10-28-2021 09:34 AM

https://cimg8.ibsrv.net/gimg/www.rcu...10f696d171.jpg
https://cimg8.ibsrv.net/gimg/www.rcu...b556a00041.jpg
https://cimg7.ibsrv.net/gimg/www.rcu...cf5dd7a44e.jpg

dr.tom 12-17-2021 12:28 PM


dr.tom 12-23-2021 11:16 PM


dr.tom 03-14-2022 09:22 AM

https://cimg4.ibsrv.net/gimg/www.rcu...3512afc5af.jpg

marksp 04-24-2022 06:17 AM

Jmb mb339
 

dr.tom 05-06-2022 01:37 PM

nice one marksp!

here is vid from yesterday


https://cimg2.ibsrv.net/gimg/www.rcu...81d8c85273.jpg
https://cimg3.ibsrv.net/gimg/www.rcu...99f76b9d6b.jpg
https://cimg4.ibsrv.net/gimg/www.rcu...ad15ebd0a6.jpg
https://cimg5.ibsrv.net/gimg/www.rcu...cb50dbf187.jpg
https://cimg6.ibsrv.net/gimg/www.rcu...a7c54d97b6.jpg

dr.tom 05-13-2022 10:21 PM


dr.tom 05-16-2022 02:21 AM


https://cimg3.ibsrv.net/gimg/www.rcu...fb9f422d61.jpg


https://cimg4.ibsrv.net/gimg/www.rcu...261423ff8a.jpg
https://cimg7.ibsrv.net/gimg/www.rcu...f5368d0ab7.jpg
https://cimg0.ibsrv.net/gimg/www.rcu...2e0bd9fbc1.jpg

N4S 11-12-2022 10:10 AM

Thanks for detailed photos and videos! I just bought one.

Where is your CG? I noticed you are using 4 batteries, what size are they and did you have to add any weight anywhere?

dr.tom 11-14-2022 12:20 PM

nice! post photos of your setup here too please, would like to see how others made it ( I've put all below deck but if I need to change something it takes longer)

my CG is 155mm, but first try the 145mm and go slowly to 150mm if you feel a need.

there is a bigger thread about this model at german forum but google translate can help you out a lot,
it's worth scrolling over.
https://www.rc-network.de/threads/jm...macchi.725229/

Yes, I started with 4 batteries,
2 for RX/servos LiIon 2S (Jeti Central box 220 - 2 inputs)
1 for turbine LiFe 3S
and third LiIon 2S for lights/retracts

but later removed 1 LiIon and I use retract channel (from CB220 ) which gives a PWM signal to retract controller, also to power it
same with lights, that channel from CB220 with PWM signal for OFF/ON, also gives power to that controller
and smoke pump ch also gives power to smoke pump (all those 3 devices have stock separated PWM input for RX side and PW input for +/- 8V, but since CB220 has fused protected outputs, I have great trust in it, so if somethings shorts out, it won't bring the whole plane down, only that channel on CB220 will go off until power is restarted....


we just had a small exhibition of RC planes here for 2 days, around 15-16.000 people came and this small MB was most advanced jet there, 80's something right? :) , next to it was mig21 from 60'
https://cimg3.ibsrv.net/gimg/www.rcu...7479b2a2c2.jpg


https://youtu.be/-6wp0xXEMxQ


N4S 11-14-2022 08:53 PM

Thank you for the information! Your jet looks and flies great!

I printed the cockpit you designed and they look fantastic! Thank you for making the files available. I am almost done with my jet and will post photos soon.

extra 300 11-18-2022 03:32 AM

Very much interested in the cockpit for the MB339. Appreciate to let me know if it is available how to receive it.
Thanks in advance

dr.tom 11-18-2022 03:43 AM

Thanks for your interest,

it is free
https://www.thingiverse.com/thing:5137073

you only need to print it and plastic for that costs less than 1$

https://cimg4.ibsrv.net/gimg/www.rcu...5ee2f16f33.jpg
https://cimg6.ibsrv.net/gimg/www.rcu...e4550c5585.jpg

https://cimg5.ibsrv.net/gimg/www.rcu...baabbf840b.jpg


Agrav8ed 11-18-2022 07:15 AM


Originally Posted by dr.tom (Post 12751624)

That looks great. I would like to use it if you don't mind. Is there a file for the sticker sheet also?
Thanks,
Tone

dr.tom 11-18-2022 07:31 AM

Use it freely!

Those screen images are not stickers but cutouts from a 50cent photo made at grocery store(machine that prints photos via bluetooth from phones)
so will try to find that file on my PC, that I've compiled from few googled HUDs and scaled at different sizes
so I coild test fit which one os ok when cutted. Nothing too scientific or mega scale, just a fun effect for me. since everythig you do is better than those pink stock sticker HUD

https://cimg3.ibsrv.net/gimg/www.rcu...b18bd1d3ec.jpg

N4S 11-18-2022 10:16 AM

The cockpits dr.tom designed are perfect fit. I printed them in gray. I have not put any sticker on them yet.

Here are few photos of mine. Even at 155mm CG, it is still tail heavy, planning to add some lead to the nose. The outer wall of the thrust tube bent in several places after the first engine run but the inner wall s fine. On the positive note, the jet is very light and assembly was quick.

https://cimg1.ibsrv.net/gimg/www.rcu...5b9ece7af6.jpg

https://cimg0.ibsrv.net/gimg/www.rcu...607e1d8249.jpg

https://cimg9.ibsrv.net/gimg/www.rcu...7a27984c82.jpg

https://cimg7.ibsrv.net/gimg/www.rcu...3d2cee4402.jpg

dr.tom 11-18-2022 11:02 AM

Nice to see others setups and experience, yes 155 can be tail heavy, try 135-140 at first.
your turbine is a lot lighter than mine(900 vs 1300g) so its weight is not what is making you tail heavy,
you have set it all way back there,
if you move it closer to wing spar, you can have right CG without need for lead in nose i believe

(p.s. I am looking ito going k102 way next spring too)

https://cimg6.ibsrv.net/gimg/www.rcu...76d68edf9a.jpg



about tube... it is all described on german forum, the thrust tube is welded on both ends, you need to set one edge loose, I opted for front one to keep end part working (inner shorter than outer, for cooling)
but If I had to do it again, I would just cut it at rear, since I measured minimal expansion which would not disturb its function at the rear side...

google translate with right click whole page in Chrome.... a lot of info there
https://www.rc-network.de/threads/jm...#post-12116179


https://cimg0.ibsrv.net/gimg/www.rcu...69a572135b.jpg

N4S 11-18-2022 11:55 AM

Thank you for your tip on the thrust tube dents! I will look into it.

As for moving the engine forward, the position of thrust tube is the constraint. If I move it forward, it will not be in the specified range of turbine nozzle to straight pipe. The one I got is supposedly a newer version. It came with light kit, unfortunately, they went up in the smoke as soon as I connected them to the light controller, so I removed them and covered the holes. I am not sure what else has changed in this version, I know the wing connectors are different than my friends MB339, he has the previous version without the light kit.

https://cimg8.ibsrv.net/gimg/www.rcu...83b2fea946.jpg


dr.tom 11-18-2022 12:05 PM

Mine from 9.2021. came with lights, smoke pump and smoke tank, round clear UAT, and single black wing connector (like for PC ATX power supply)

Before there were 2 connectors per wing, molex style (white) and lead in the nose.

I believe you can move tube a bit forward too to keep right distance from end of turbine nozzle of course. Rear part is not that critical, venturi helps with cooling, center blast is hot, the air that comes between two layers of tube creates a circular shield even after tube ends in the rear to some extent....

Agrav8ed 11-18-2022 12:22 PM


Originally Posted by N4S (Post 12751664)
The cockpits dr.tom designed are perfect fit. I printed them in gray. I have not put any sticker on them yet.

Here are few photos of mine. Even at 155mm CG, it is still tail heavy, planning to add some lead to the nose. The outer wall of the thrust tube bent in several places after the first engine run but the inner wall s fine. On the positive note, the jet is very light and assembly was quick.

https://cimg1.ibsrv.net/gimg/www.rcu...5b9ece7af6.jpg

https://cimg0.ibsrv.net/gimg/www.rcu...607e1d8249.jpg

https://cimg9.ibsrv.net/gimg/www.rcu...7a27984c82.jpg

https://cimg7.ibsrv.net/gimg/www.rcu...3d2cee4402.jpg

Do not fly that tube like that. You are asking for trouble and for the pipe to crumple in flight. Cut one of the end to allow it to expand properly like in the above video.
Thanks,
Tone

N4S 11-18-2022 12:53 PM


Originally Posted by Agrav8ed (Post 12751683)
Do not fly that tube like that. You are asking for trouble and for the pipe to crumple in flight. Cut one of the end to allow it to expand properly like in the above video.
Thanks,
Tone

Thanks! Will do.

N4S 11-18-2022 12:56 PM


Originally Posted by dr.tom (Post 12751679)
Mine from 9.2021. came with lights, smoke pump and smoke tank, round clear UAT, and single black wing connector (like for PC ATX power supply)

Before there were 2 connectors per wing, molex style (white) and lead in the nose.

I believe you can move tube a bit forward too to keep right distance from end of turbine nozzle of course. Rear part is not that critical, venturi helps with cooling, center blast is hot, the air that comes between two layers of tube creates a circular shield even after tube ends in the rear to some extent....

So we probably have same version, as I only have single black connector for each wing too. Mine did not come with smoke pump or tank, but it came with smoke injector which I thought was odd. Thanks for all your help!


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