RE: SkyMaster MB339 Build Thread
 

Anton,
I got the same tail pipe with large bellmouth as F-18 Diamondback, ill it atill work with my Jetcat 160 Titan?
Lawrence

RE: SkyMaster MB339 Build Thread
 

Hi, Lawrence

yes,

your tailpipe is for P-120 to P-160, No, problems, we have no make the F-18 tailpipe for P-180,

Best regards

Anton

RE: SkyMaster MB339 Build Thread
 

OK, the build continues...

The work on the landing gear doors continues...Many thanks to the guys who offered help on hinging them.

The main door is where I started. I have never hinged a door before so it was all a learning process. I now have the doors on the left wing about 80% done. I still need to do a final fitting and set up all the gap seals and whatnot. I employed some "that looks about right" engineering when it came to the ram and link installations. See pictures....

RE: SkyMaster MB339 Build Thread
 

A few more....

RE: SkyMaster MB339 Build Thread
 

No more progress on this one ???????

RE: SkyMaster MB339 Build Thread
 

I am working on the other wing, but it is the same stuff...Had minor setback as other in service jets have had mechanical issues. I should be ramping up on this one soon.

One thing I will throw out there is finishing the jet, as in paint. I have contacted a local painter and he is quoting me 1600 USD to paint it. I have done a lot of painting of glass helicopter canopies so I have some experience but I am not sure about a big project like this. I figure that for 1600 bucks I could own the spray equipment, buy all the supplies and do it myself.

Not sure if I should go pro or home brew...anyone have any advice?

RE: SkyMaster MB339 Build Thread
 

I went for the fully completed 339 therefore....that is if Anton starts to reply emails, my dealer has not heard from him since the Chinese Holidays started.... The paintwork (i have seen the completed one) is truly a work of art, I guess I cannot get even close....

I spray painted many models and I did not succeed in getting everyone 100%. There is always an area You overdid, (especially near sections where the stab or wing meets the fuse) thus getting drips, or when removing tape and it sticks to fresh painted stuff, or the ONLY fly in the garage that decides to rest on the last paintlayer...
There is a long and steep learning curve with painting. It is not that You have to buy all equipment, if it were only that easy.... At least You need also an area that can be used for spraying, that means: heated, lighted, ventilated....plus a friend who has good experience in let's say painting cars!
I made myself a steel "grill" in which I can alternately fit in a fuse or wings to get an optimum angle for spraying, and helpful tools to hold all small parts etc. Preparation for painting takes a whole day for me......

Btw some shops sell those air compressors with a complete "set", including a spray gun. Give that one right away to Your children for water fights in the garden, absolutely rubbish stuff normally! A good professional spray gun will set You back over 500 U$....

I gues You should shop around more and get some more price proposals. Delivering a model well sanded and prepared for painting saves them a lot on hours.

RE: SkyMaster MB339 Build Thread
 

Diamondback

Before I painted my 339 I had only ever used spray cans for smaller projects. For the 339 I decided to paint it myself in a scale cammo scheme. I bought a compressor and gun at my local B & Q (Home depot in the US?) for £85 ($180) and decided to use latex house paint. I had the paint mixed up to the three colours I needed and also got some matt clear water based laquer for the clear coat. The paint cost me £50 in total. I sprayed the model in primer first using large cans of cellulose primer, I scuffed the model surfaces first with a Scotchbrite pad.

I experimented with thinning the paint with water and found that about 25% water with a gun pressure of 50 PSI seemed to work well. I practiced spraying on some scrap sheetrock, the paint has a pronounced "orange peel" look when first applied but dries quickly to a nice level matt finish, small imperfections can be easily and quickly
touched up either using the gun or with a good artist's brush. I then applied the decals before spraying the clear coat. I used 3M door shut masking tape to separate the cammo colours and this was very effective and easy to use.

The paint has proved to be reasonably durable in sevice and in my view has many advantages in that it is cheap, no breathing equipment is required,cleaning up only needs water, you can spray in fairly low damp temperatures. Refer to the thread "Spraying with emulsion paint" for more info.

If you intend to spray 2 pack type paints etc. you may need a better gun as Richard suggests but I certainly don't think you need to spend $500 on one. I was very pleased with the quality of finish my $70 gun produced.

Best regards

John

RE: SkyMaster MB339 Build Thread
 

John,
I agree with Your suggestions, but there is a LARGE difference whether You want to dress it with a cammo scheme, or a shiney one like the Frecce Tricolori paint scheme. Any imperfection will be seen on these glossy surfaces. And for durability 2 K lacquers are way better as waterbased ones. To get optimum result You need a high quality spraygun. Of course I started long ago with a cheap one, but after upgrading in steps with better equipment, I found that the end result improved every time. The expensive ones make much better fine spray as do cheap ones, thus reducing the risk of droplets (or is the correct wording "sagging"?)

Professional spray guns operate with 2 Bar pressure, which is 30 PSI

An expensive plane like the MB needs a nice dress :) No good to go the easy way out on this one.

RE: SkyMaster MB339 Build Thread
 

Lots of good sugestions...

I have been planning on doing a "Red Bull" version so it would be a very shiny paint job...I like the military idea as well but I have not found a scheme that really grabs my attention....

Not sure what to do at this point....

RE: SkyMaster MB339 Build Thread
 

Cammo dressing has a big drawback, eg., you tend to loose sight of it sooner than with a bright colour scheme. With sight I mean a good reference of bank and attitude. No big deal, cammo was exactly made to do this!
Plus, in the end, all camouflaged airplanes start kinda looking the same (no offense meant for those who love them...)
Personally I find more satisfaction in making a new model bright and clear with a perfect finish. Plus You can use Your imagination to any extent to make an exclusive scheme.

Keeping a model as long as possible in such a state requires extra care though, for instance in avoiding hangar rash. On a camouflaged surface a few scratches more add even more to "scale".

RE: SkyMaster MB339 Build Thread
 

Richard

I tend to agree with you on the high gloss finish, I have never tried that so I can't comment. The water based paint works fine for cammo schemes though. The 339 is so big it is quite difficult to get disorientated especially if you fit the tip tanks which really help with the visibility.

Best regards

John

RE: SkyMaster MB339 Build Thread
 

The camouflage on my Spiderjets F16 combined with 5 tailfins and only tiprails installed makes it to be monitored carefully in serveral turns of the pattern. Hazy conditions in the higher layers like last weekend with somewhat milky sunlight, I tend to stay close and low.
But nice it was!

RE: SkyMaster MB339 Build Thread
 

As this thread has been silent for a while, I am picking up the story, as I have received my MB (ready painted in Frecce Tricolori colours) some time ago and now busy working on it.

A few things:
The idea stolen from my friend Leo (who also builds one) I made a temporary stand to accomodate all the gear components and test it. Good idea, as I found out that some Skymaster door cylinders were leaking. (new ones will be sent, good service).
The gear itself proved flawless, not only it looks sturdy and made to a high standard, but it works just perfect. Almost comic to see that gear flap upright on the bench!
The same time I could delve in the software of the Weatronic and adjust it to suit, make the Jettronics (from Sandor) work as they should.


The nosegear main door proved a headache to get it hinged right. First started with the offset hinges, but that did not work due to the double curvature of the door.
Then I looked again at the 1/1 MB pics, and noticed very faintly it has outward hinges.
So I copied that using normal Robart flat hinges.
First I glued some aluminium brackets to the door. Take care to align the vertical panes to be in line.
I removed the hinge pins and replaced it with a long 1mm wire that runs through both of them, to get both hinges working in the same hinge line, very important.
Then I tack glued one side to the alu brackets, taking care the piano wire touches the door just in the middle, any further out mounting of the hinges is not necessary.

Removed some material from the fuse side and made plywood blocks to receive the other side of the hinge. Here too, careful alignment is important
Then tack glued the othe side to the blocks.

The end result is, the door fits like a glove and is easily rotated to more than 180 degrees! You cannot get even close with offset hinges...

Now I need to touch op some parts, and tip paint the hinges, install a bracket to attach the actuator rod. I might cut back the alu brackets a bit if they stick too far inside, hampering the gear.

The long wire will be replaced with shorter hinge pins, but will definitely make them removable to be able to remove the door.

RE: SkyMaster MB339 Build Thread
 

Great post Richard....

Progress on mine has stopped as a King Cat jumped in line...I am working hard to get it finished and then I will be back on to the 339. I like your suggestions on the nose gear door hinges, I will carefully consider what you have done and may use that method as well.

Keep the pictures coming....

RE: SkyMaster MB339 Build Thread
 

F18diamond,

OK, good to hear You pick up the project again.
I have to stop a few weeks also due to an aero tow meeting this weekend in Belgium, followed by 2 weeks of slope soaring in Switzerland. Bóóóring life :) :) (I retired a month ago......)

I completed the nose doors now and touched up things. Shortened the protruding sides of the hinges a bit. Central rod will be there until project is nearly finished, for easy removal.
One correction to my statement that the original has the same setup, I looked again and it seems they are flush with the fuze. But that is because the nose door is not double curved as in the model. So my solution is a bit off scale, but the small price offers way better operation on the model.
Btw the 2 smaller nose gear doors are using offset hinges.

RE: SkyMaster MB339 Build Thread
 

HI ALL MB339 Builders
Im about to get started on building one this week so thanks to all the people who post here .
Id like to clear some doubts here . The main and nose gear struts \ links are assembled and seem to have good action and damping , so do i redo it as per the video in the SM website or i just leave it alone assuming its been done at the factory. btw they have supplied a syringe and oil and a mousse can and the nipple \tube. Also the wing bolt area at the fuse joint has barely 5mm of meat where the head is countersunk, looks like i could tighten the bolt head and yank the wing and it would come right off. am i being kinda over cautious here or just fit it and forget it . . app all who help and thanks for all the pics so far from everyone.

RE: SkyMaster MB339 Build Thread
 

Brake problem.

During testing I have encountered another problem. One brake unit is leaking air, when pressure is added. It DOES brake however, but at the cost of loosing a lot airpressure. Do Yours leake air?
The other brake doesn't work at all, no air is getting into the brake unit at all. so no braking on that one. I have emailed to Skymaster, w'll see what they answer.

RE: SkyMaster MB339 Build Thread
 

Dear Richard

I've sent e-mail to you.Please check it.

We'll arrange to send you the replacement parts after you check again with the wheel brake.

Best regards

John
Skymaster Jets

RE: SkyMaster MB339 Build Thread
 

Tks to John from Skymaster now all OK, cleared an obstruction in one and the other wheel was not plugged in one spot, which I corrected, all fine now.
BTW, I have uploaded a vid from the nose gear sequence at http://www.youtube.com/watch?v=uPJlFQvf04Q

The gearspeed itself is already softened by a Festo restrictor on the outlet of the Jettronics valve, I see I need another one on the doors as well!
Systems consists of 2 X jettronics 2 way valves, sequencing by Weatronic.
The large front door is part of the door system, however the small doors get pressure from the gear DOWN air for opening, and for doors close gear UP air. However, pressure is blocked until the nose gear touches a mechanical pressure switch that then sends pressure to the small doors.

Took a while to get it all figured out........

RE: SkyMaster MB339 Build Thread
 

I could work last week quite a bit on my MB, tackeld the wing/fuse connections. Without any previous experience working with quick air disconnects, the result was not bad.
In stead of having separate "blocks" for both air and electrics like in the beginning of this thread, I used ONE former to mount both units upon, hopefully this gives more resistance against movement of fuse and wing parts when air pressure is on.
For electric connections I used the Sub-D that is a 90 degree version, so inside the fuse it nicely looks downward in order for the leads to be routed under the tanks.

RE: SkyMaster MB339 Build Thread
 

Hi Richard,

I follow your thread with great interest.
Since last week I´m a proud owner of the SM MB 339. Unfourtanely I have to wait for thrust pipe, pneumatic set ..
to start work on my MB.
So far I´m very happy with the quality of the model.
Keep on posting.

Best regards
Christian

RE: SkyMaster MB339 Build Thread
 

What kind of servos are you using for this model ?

RE: SkyMaster MB339 Build Thread
 

Hi Gonzal0,

I will use Thunder Tiger DS 1013 MG Digital Servo.
They have 13kg/6V. I used them in my L-39 before and I´m happy with them.

Greetings
Christian

RE: SkyMaster MB339 Build Thread
 

Thanks Christian.

I wonder if the HITEC HS985 servos would work (12.4 kg - 6 volts).