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Jetlegend L39 build

Started by STORM, September 03, 2010, 21:49:32 pm

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0 Members and 1 Guest are viewing this topic.

The Saint. (Owen)

Quotewe all make mistakes but no glue got on to the model and that's what's important


I thought that is where the glue is supposed to go.  ???       ;)
Electrickery is the work of the devil.
Proper aeroplanes are powered by engines.

Pat Barnes

Quote from: STORM on September 13, 2010, 19:56:33 pm
Now the really funny bit... I managed to glue my fingers together...


;D ;D  There are those who have. And those who will...

martin lees


  " Glued your fingers together "  Hope that won,t stop you
    putting your hand in your pocket at the weekend  ;D


   Rgds    Martin

STORM

Ha ha! Didn't anyone tell you pensioners don't have any money. You'd better send me your address Martin.

Vinceyboy

Well your certainly marching on with it, but "WOW" all those problem mistakes with manufacturing, no wonder some of the guys are turning back to traditional building of models, less expensive and better quality :af

Still I suppose it gives the engineering brain a challenge, but annoying when you have paid so much money for the kit :'(

So what's your next project Sverrir? a friend has built and is flying one of those CARF Tutors and is well chuffed with it, said it fly's like a trainer :)
"Jet flying is strictly on a shoestring"

STORM

I think when you are talking jets Vince you are expected to be able to deal with these small problems, the important thing is to spot them.
Don't get me wrong, it's a generally superb kit and when finished all will be forgotten.
Also, I can be a bit of a perfectionist sometimes but I can't afford to keep buying replacements all the time.
Even simple jets like Boomerangs for example need extra work to fix small problems, goes with the territory.

Vinceyboy

Agree 100% with you Gary, they cost too much hard earned money to be complacent with, everything needs to thoroughly checked over & over again, and as Ali said with servos etc. better to have overkill than not enough :af
"Jet flying is strictly on a shoestring"

Alex48

The perfect ARF/kit doesn't exist   :'(

Currently building a kit that's well into 5 figures to buy and kit out etc... It's still got issues.... ::)

My dream is to one day build a model that goes together without requiring modification to make it airworthy.

The Little Jet Company
www.facebook.com/TheLittleJetCompany

selleri

Quote from: Vinceyboy on September 14, 2010, 09:02:08 am
So what's your next project Sverrir? a friend has built and is flying one of those CARF Tutors and is well chuffed with it, said it fly's like a trainer :)


Undecided, price will be bigger factor than with the Viperjet though, always fancied a Eurosport.

Quote from: Alex48 on September 14, 2010, 12:09:56 pm
My dream is to one day build a model that goes together without requiring modification to make it airworthy.


I'm aiming for world peace, I think I'll win.  ;D
Sverrir  - Icelandic Volcano Yeti - RCMF Tech Team

STORM

Sverrir, the L39 is worth a look, a helluva lot of airplane for the money!

Alex, tell us, tell us, tell us!!

pylon²

Looking good Gary :af hey picking up the F5 tonight :P
Have a good time at Jetpower.

Richard. :af

STORM

I bet you are sooooooooo excited!

Which kit is it?

pylon²

Quote from: STORM on September 14, 2010, 18:05:31 pm
I bet you are sooooooooo excited!

Which kit is it?

Feibao F5,  96" fuz, 59" wing. complete with missles, tanks scale cockpit etc. :D

STORM


pylon²


Vinceyboy

Even "dyed-in-the-wool" warbird pilots like Richard have now been jet brain washed :''
"Jet flying is strictly on a shoestring"

STORM

The first aileron servo and linkage is now complete, the extension lead was attached to the servo just before this and my usual securing lockwire added.
At this point the aileron has not been hinged.

STORM

By way of relieving the boredom I have am now working on the flap setup.
Decided to cut out the slots for the substantial flap hinges.
Everyone has thier own preference for how to achieve this neatly.
The four flap slot positions are finely marked, after checking the marks were correct I masked them off with masking tape and drilled slightly undersized holes each end of the slot.

STORM

September 16, 2010, 11:33:05 am #98 Last Edit: September 16, 2010, 12:00:36 pm by STORM
The rest of the slot was then drilled and carefully routed out with the undersized drill.
These flaps taper and therefore the depth of the drill had to be watched carefully at the tapered end using the trusty masking tape as a stop gauge.

The slots were then increase to the correct size end the end points filed square with a small diamond file.

STORM

As an example of how easy it is to mess up only then did I notice that the hinges that insert into the slots are a different thickness, wider in the wing than the flaps, this could have led to the flap slots being drilled and shaped well oversized.
I've often said that when I build a jet I employ 99% thinking and 1% building, probably why I'm so slow!

STORM

Slots were finished off using final drill size and ends filed square using a diamond file.
The final drill was again marked with depth tape, as the flaps taper considerably in chord and section a piece was cut off the end hinge to avoid the drill penetrating the top skin.

I am aware that some guys use a tapered pointed fine saw to cut these slots but JetLegend in their wisdom have inserted substantial hard balsa blocks at full depth for the hinges.
Much credit to them as this is a substantial weak point on some arf's, they just use a thin plate which may be easier to saw through but nowhere near as strong as large blocks.

STORM

All slots cut and hinges positioned for alignment check.

Also pic of finished tailplane assembly.

STORM

Here we go with another slight problem.

Because of the flap taper the hinges do not line up correctly.

The flap l/edge also tapers some 4mm along it's length, this means that at the widest part the hinges foul the l/edge, this will require some thought.

If the slots are relieved to allow the hinges further forward and clear they will not align on the pivot points, may have to relieve the hinge itself to clear.

That's it for now, I will think about this as I wander round JetPower with the Yorkshire lads!

Thanks for viewing this soap!

More next week!
Gary.

selleri

Take lot of pics at JP for those of us left at home!   :af
Sverrir  - Icelandic Volcano Yeti - RCMF Tech Team

Alex48

The Little Jet Company
www.facebook.com/TheLittleJetCompany

STORM

Well, safely back from a great weekend at JP, managed to do a little more this evening.
Cut the servo arm slot and mounted the first flap servo.

STORM

Time to mount the second aileron set up in the tip tank.
I was going to copy the measurements, angles etc from the first one but something did not look quite right.
I decided to check by laying the two tanks side by side, just as well as a disaster was lurking once again.
Turns out the servo mounting plates were in a completely different position in each tank. Everything was carefully made up, pushrods exactly the same length etc. and lined up by eye.
You can see from the pic what a disaster this could have been, mechanical control moments would have ended up wildly different, impossible to dial out on Tx cos I am opting to use the two ail outputs on one channel via the powerbox to save a channel for something else.

Vinceyboy

Luckily your thinking clearly all the way on this one Gary, "measure twice" etc. I was given to understand that J.L. were one of the better kits, just goes to show :-\

Still, it's looking good mate :af
"Jet flying is strictly on a shoestring"

STORM

Don't get me wrong Vince, I don't think there is a kit on the market that's "perfect" I'm just pointing out the odd correction that's needed to help anyone that builds one in the future.
Nothing so far that is not correctable, the kit generally is superb, the best glue job I have ever seen from China in fact.
We went to an aircraft museum in Germany on Monday and luckily they had a f/s L39 there which was useful for details photo's etc.
When she is 100 feet and climbing all the little niggles will be forgotten!
Gary.

Vinceyboy

Yes, been reading the report on JP on the other channel, wish I could have been there :'(
"Jet flying is strictly on a shoestring"

pylon²

[quote .
When she is 100 feet and climbing all the little niggles will be forgotten!
Gary.
[/quote]
You will be MEGA impressed when you fly her. I love mine and hope my F5 flies 1/2 as good !
Richard.

STORM

September 22, 2010, 22:17:27 pm #111 Last Edit: September 22, 2010, 22:25:38 pm by STORM
I hope so Richard, I need to get her in and out of a very bumpy 150 yd strip! ;)

I think t/o will be a bigger problem than landing by all accounts.

Supposed to be a winter project but I can't keep my hands off it.

Thanks for the encouragement,

Gary.

pylon²

September 22, 2010, 22:31:14 pm #112 Last Edit: September 22, 2010, 22:38:47 pm by pylon
Quote from: STORM on September 22, 2010, 22:17:27 pm
I hope so Richard, I need to get her in and out of a very bumpy 150 yd strip! ;)

I think t/o will be a bigger problem than landing by all accounts.



Gary.

If I were you I would make the noseleg dampening stiffer on the noseleg as you will find on grass the nose will dip and decrease your angle of attack resulting in a longer take off run followed by a massive leap into the air. I fitted an extra stronger spring to mine plus added a length of tygon pipe inside the springs. Cheers Richard.

STORM

Seem to have spent a lot of time today with very little to show for it.

I decided to use some brass tubing on the elevators and ailerons hinges as there is a fair overhang leaving a good deal of unsupported plastic hinge on the tail and wing trailing edges due to the large skin overhang and well recessed hinge centrelines.

Suprising how long it takes to cut 18 bits of tubing 34mm long. Used a tube cutter for this, then on to deburring the bores with a scalpel.

This job has to be done with a lot of attention to avoid a trip to the hospital for even more stitches! :''


STORM

Yes Richard, I was well aware of that potential problem. I don't suppose you remember where you got your spring from do you?

Usually though I hit a channel half way down the strip which alleviates my decision to rotate, my models normally get chucked into the air!

Has to be a 160 jobby for sure.

STORM

Final job this evening was to epoxy the hinges into the ailerons, frequent checks when curing to check line up and constant depth with the robarts. And yes, I did remember to vasaline the pivots! :co

pylon²

Quote from: STORM on September 22, 2010, 22:38:24 pm
Yes Richard, I was well aware of that potential problem. I don't suppose you remember where you got your spring from do you?

.

From my bits and bobs box ;D. Yes a 160 is a must if your limited on space. Also the noselegs pins are quite soft watch your leg does not bend back in time on bumpy grass. In some ways though its not a bad thing having soft pins in the noseleg.
Must get on with the F5!!     Richard.

STORM

Couple of f/size pics taken in Germany weekend.

JetLegend certainly got their new wheels accurate!

STORM

First job today was to epoxy the brass support tubes to the hinges, this was done after the tubes were rough filed to provide a key for the glue.
I had the forthought to cut the tubes slightly longer than needed, this left about 4mm to top up with a nice blob of epoxy to add more shear strength to stop the hinges pulling out should they wish to!

STORM

I left the surfaces to dry and turned attention to the fin/rudder.
The rudder servo sits in the fin with a small suppied 3mm pin which is inserted into an aluminium slot in the base of the rudder, this is done so no unsightly linkages and horns can be seen from the outside.
On the RCU forum most people opt out of this system complaining of rudder flutter possibilities with this set up.
I considered that a long metal servo arm to increase the leverage may work so am giving it a try.
A standard servo is too wide to fit so I am only using a small 5 kg one which may prove to be not powerful enough.
I had to modify the cut out for the new pin position and fitted a nylock nut for security, not that bothered about a lot of rudder movement, never been a knife edge freak so we will have to see how much movement is possible.