skywarrior

Hi
Have been looking at the geometry of the gear doors from my original post and thought I might improve on it. Took a tip fromArtchrisistic 1 and pivoted over the center line. Had to build a platform for one of the larger cylinders but works very well, and its shut ! You can see the modified hinge point as well using the Robart ali hinges.
All needs cleaning up but that comes later.

I am using the Jetcat 180 Rx as on the orignal and came across a tank from a friend which fits very well at 2 litres. This plus the original 3.4 ltrs gives potential for a large fuel load and relaxed flight times. Probably just use 4.5 ltrs. we shall see in the spring

skywarrior

Hi Chris,
I am working on a model kit received 3 weeks ago and it seems they change things so I enclose how my nose gear steering has been set up.

artchristic1

Hi:

In the rear of the plane ware all the exhaust heat is, you should
consider using metal link horns and ball joints due to these parts made in
plastic will turn soft and/or fail.
Just to let you know.
Good set up though.

I used two servos for the elevator..
You don`t need it but I like the two servos for safety reasons.
A personal thing being that it is a big plane.

artchristic1

Hi Skywarrior;

Nice set up.
Glad the gear doors worked out for you

As for the fuel set up, your turbine will be using one tank at a time and that is
not the best set up due to the fuel pump will be working harder than normal pumping
fuel with a lot of restrictions.
You should use a Tee between the two main tanks to feed the
single tank at it`s over fill port then connect the single tank feed port to your air separator tank over fill port or engine and to fill up the tanks use your
single tank fuel port or air separator tank with a Tee and the fuel flow will be reversed. Add a Tee to connect your two main tank over fill ports together and direct it to outside the plane.
You will see that when the engine is running, that the two main tanks will drain at the same time keeping the single tank full at all time (air free).
Just think about it.

skywarrior

Hi
thanks you are right about that. Totally wrong plumbing dept.

Is it possible to re load you attachment at a higher resolution as I cannot read the annotations.

cheers

David

artchristic1

Try this.
For me it was very large.

skywarrior

Apologies it must have been the i Pad software as its fine on my main mac.

Thanks again

skywarrior

Hi
Thanks for the plumbing tips and also the plastic elevator tip which I am changing for metal versions. Sometimes we get so immersed in this stuff we overlook the simple principles of common sense.
We have lost our tarmac flying field after 20 years and I will be flyng off a full size grass airstrip in future. This is one rason why I chose this plane re U/C being trailng link and looking very worthy. It is not the mown and tended Club strip although pretty well cared for. I have been looking at the front nose gear mounting with a view to beefing up the mountings and have ended up with wooden blocks cut and shaped to fit the upside of the mounting ply plate. I would have liked to use carbon plate but could not see a way of screwing into it at a 3mm thickness. So my solution so far is to use the wooden blocks and drill the ali gear mounting plate with the front holes slightly further to the rear ( as at present the front holes in the factory ply plate are 3mm from the front leading edge ! I will use 4 mm cap screws as I know I can get them out with good tools unlike the self tappers used by the factory.

As always a problem stops it being simple and there has to be clearnce for the gear to slide out forwards without the 2mm nipple catching. this means the left hand plate has to be thinner to allow this to happen, hence the two different thicknesses. A good solution would have been to turn the end cap of the ram 45' so the nipple exits at 12 o'clock but will it leak ? The factory could make this a better job all round if this was done at source then the mounting area could be belt and braces.
This was a useful way to spend the afternoon of New Years day here in UK as it was grey, raining, and very unpleasantly windy !


Regards

bluescoobydoo

I would not worry to much about the mounts not has a problem with mine even after several arrivals it more likely to be the retract pin that will bend but it is soft so will bend back while in position

artchristic1

Hi Skyworrior;

Nice work and thinking.
Another thing that I did in this area was I soaked the wood with
thin typ Loctite glue. You can also use any type thin glue.
The good thing about it is that the wood will keep obsorbing it
till it is saturated and starts to set.
You ever noticed that when plywood breaks it delaminates at
the holes, well this method will at least transfer some of the load
elsware.
Try it at the inside and edges where the holes are first.

I did this at all the front bulk heads and holes,
I learned this from my SM F-4 and it cured the problem when things
were delaminating.

madmodelman

There should be a 3/4" gap between the end face of turbine exhaust and f face of thrust tube. Too close can cause pipe overheating problems it cannot draw enough cool air through the gap.
JetCats words, not mine!

artchristic1

Thanks Madmodelman for your concern and input.
Jet Cat is right in some cases but not all.
The modeler should always focus on cooling air.
I trust my set up and I have always checked the temp at the exhaust in the plane to see what it
is doing and I have not noticed a dramatic change in temp at full static throttle for a
long period of time.
Readers can creat cheater holes around the rear of the ducting to lower the temp if they like
to feel confortable and safe.
Again this is my set up to show readers what I did but not for anyone to fallow.

I sent the Cockpit tub you sold me to Camlex to finish.

madmodelman

That's ok Eugene, not trying to tell you how to do it!

artchristic1

It`s always good to have inputs.
That`s what makes this tread so good.
I will be useing a Weatronics 3 point gyro on this plane for windy days.
I here it is the best on the market in Germany.
Did you get your plane flying again?
Thanks for your tips in helping me building this plane.
I have to wait till next season for the first flight.
Today I will work on the wheel alignments and C/G point.

madmodelman

Yes, I managed a couple of flights last weekend thanks, it still flies well. Just started an F4 assembly by way of a change!

skywarrior

Hi,
Have a look at the "Power Box Royal". Its expensive at fisrt sight but is an integrated 3 axis gyro with a gps speed sensor for rates, plus just about every feature you could ever want including a gear door sequencer and on board display panel for all info. I am putting one in the L 39 and have one lined up for my Tutor which at present has Power Box SRS competition. This is the same without the 3 axis gyro and at present the Tutor has a GY 431 single axis gyro on the ailerons.
I am just getting into the gyro stuff and I must say so far its impressive. The L 39 should benefit from the gyro as it fish tails a little. If the single axis gyro on my old L39 is anything to go by then I am on the right track.

http://www.powerbox-systems.com/prod...royal-srs.html

Hope this helps

artchristic1

Cool.
Nice set up.
I am a little on keeping my plane very basic but good quality.
I prefer not to go too high tech.
Personal thing only.
Yes the Gyro system will be very good in this plane.
I will take a look at the Power Box Royal later.

artchristic1

Hi I had an F-4 and I must say it was the best War Jet Plane I have flown.
It is a very demanding plane but once you get the hang of it, you will love it.
Keep me informed please.

skywarrior

Hi,
I am getting on with my build for this new L39 ( this years model with opening front hatches and pre built flaps etc. (I am not sure if there is an intermediate model between mine and the red white blue version 2012 which is why I am trying to be specific).
Does this model still come out very tail heavy (Mine will have one servo for elevator Savox 20lb) plus a 180 RX as power plant.

I am at that stage when probably I should put the plane together and throw things here and there to see where it balances etc. However a couple of comments from builders of the same model would save a lot of fiddling around and I can do broad strokes and finesse later.
Thank you D

David

madmodelman

Eugene, don't want to hijack the thread but here's some pics, also the turbine.
David, lob a couple of 5000mah Sub C's in the nose, that should sort it!

artchristic1

That is one cool machine.
You are going to love the look and feel in the air.
You will steel the looks from other modelers at the field.

WOW

artchristic1

Hi Skywarrior;

Yes the new version come still tail heavy.
It is good in one sence. You can play
with the usefull weight in the nose, like bigger batteries and an avionic
area.
I put all the batteries and gear sequenser, brake servos and gear servo valves
in the nose.
You will have no worries balancing the plane.
I used all standard size servos just to keep it simple and used the battery packs to
find the C/G point just like Madmodelman.
I kept my cockpit weight with full body pilots (2X) as part of the nose weight.
Don,t forget that there is a lot of thing to put in the nose and forward area.
All our plane will come out around the same weight.
Can't get around it.

skywarrior

Hi,
Thanks for the photos. I am wondering how you keep your front bay side doors fixed. Have you removed the converted spring rams and If so how are the doors fixed as the photos dont show any fixing method as far as I can see.

I intend to put most of the stuff you have up there too but I did not want to go in that direction and find it should all be nearer the CG point or at least on the main bay area. I am intending not to use any lead this time.

Regards
David

artchristic1

That pic was an unfinished zone. Things have changed since then.
The more you use the forward bay area the less weight you will need to balance your plane.
When you have all what you need in the front to service fuel, batteries, turbine ECU data hook up and air tanks, the less you will need to open
your cockpit hatch.
Try to keep all what you need in one area it will help when you are at the field.
Your plane will need a lot of weight in the front to bring the C/G forward so don't be too cheap.
I used the spring cylinders at the front doors. They work fine and are strong in the closed position.

If you put most of your stuff near the C/G point the more your plane will weigh due to you still have to put weight in the nose area.
You will see I am right when you get to that point ask Madmodelman he is flying one right now.
He did the same by placing his batteries in the front as useful weight.
We have bonus doors so use them.
All what I have in the front' I still have to add just a touch of weight so I put my fuel air separator tank closer
to the front on the floor with non useable fuel in it. This is fuel that the turbine cannot use (Main Tanks Empty) and balanced my plane in this configuration.
We sometimes do this on full size aircrafts to find C/G window.
I am an aircraft engineer.
I ordered my plane without the doors and hinging done so things are a bit different than your plane
Again this is my set up to show readers what I did but not for anyone to fallow.

Hope this helps

madmodelman

You're spot on Eugene, I'm no fan of Nimh's but I use them in this model (& the F4) right up front in the nose. Uat & pump up front on the rc plate and two heavy pilots. NO lead!
Gary.