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A4 Skyhawk build

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Old 11-25-2011, 04:30 AM
  #51
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Default RE: A4 Skyhawk build

Hey Alex,
I Have been working on some other projects. So, I have been working slowly on the A4 (ie no Alex in front) I decided to mount the servo in the stab for the rudder and will post some pictures when I get a chance. I have the fuel cells assembled and ready to be installed. I have set up the speed brakes (two way evu2) and the nose gear extension (one way evu-2). I have to figure a way to run the speed brake air lines away from the pipe, esp with the scale detail that I made inside the brakes. so Alex what are "we" doing with that? I need a way to "tidy them up" before the get to that first former.
All the best,
Peter
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Old 11-25-2011, 09:29 AM
  #52
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Default RE: A4 Skyhawk build

I'll take some photos for you when I get back from work in a few days.

Cheers
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Old 12-02-2011, 02:44 AM
  #53
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Default RE: A4 Skyhawk build

Hi Peter, Sorry........I've been holed up in a Hotel and this slipped my mind.....at least it has free wifi...

Basically I ran the air lines through the former just aft of the speedbrakes then ran them through the next former forward. I then Tee'd them off just past the second former. This keeps the airline tucked tight to the fuz.

I've just ordered all the radio and ancillary stuff for this so a few customer projects to finish off then I should be back on it

Cheers, Alex
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Old 12-06-2011, 02:06 PM
  #54
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Default RE: A4 Skyhawk build

I got round to doing that photo...

How does your avionics hump attach Peter? If its glued on you can't get the hatch off unless I use four catches instead of the traditional two on the turbine hatch. I've just got a plain moldong for the hump but it does seem to have slots cut for catchs etc...
Cheers, Alex

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Old 12-06-2011, 03:12 PM
  #55
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Default RE: A4 Skyhawk build

Thanks for the photo, got my airlines run. Yes mine has four latches and a little hard to get on and off unless you have four hands..... or your flying buddy....
The latches go into the holes I tried to show in the pictures, the holes have a wooden washer on the glued inside.
Yes the hump is glued permantly to the hatch....
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Old 12-06-2011, 03:44 PM
  #56
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Default RE: A4 Skyhawk build

I'm getting itchy fingers watching yours progress...

Thanks for the help.

Cheers, Alex
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Old 12-07-2011, 03:17 PM
  #57
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Default RE: A4 Skyhawk build

Slow progress but I did a little tonight

In the last few weeks I've been on an eBay BBI pilot binge and managed to get four pilot figures at reasonable cost as well as some different flight suits to suit my scheme which I'll attach the correct insignia to. The one thing that did amuse me is that the boxes arrived in an untouched pristine condition from a collector still with the original cellophane wrapping on them. I soon ripped it all apart disposed of everything bar the head stuffed the flight suit and glued the head on creating a lightweight pilot for the A4. He's not in the correct position yet but you get the idea...
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Old 12-07-2011, 03:21 PM
  #58
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Default RE: A4 Skyhawk build

and on the subject of pilots I've had Churchill Creations make me an animatronic pilot from one of my eBay purchases. He sent me the video tonight but I'm yet to receive it. The A4 cockpit is a tight squeeze plus I'm wary of adding any extra weight so it might go into another project but couldn't resist getting one anyway

http://www.youtube.com/watch?v=BmLgdy9mtes
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Old 12-07-2011, 03:24 PM
  #59
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Default RE: A4 Skyhawk build


Quote:
ORIGINAL: Alex48

and on the subject of pilots I've had Churchill Creations make me an animatronic pilot from one of my eBay purchases. He sent me the video tonight but I'm yet to receive it. The A4 cockpit is a tight squeeze plus I'm wary of adding any extra weight so it might go into another project but couldn't resist getting one anyway

http://www.youtube.com/watch?v=BmLgdy9mtes
The programming can be changed...

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Old 12-07-2011, 03:25 PM
  #60
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Default RE: A4 Skyhawk build

Servos have been fitted to the horizontal and vertical stabilisers. I've made them all detachable although the stabs will only come off during winter storage where as the fin will be removed for transport. I use rubber stoppers and an engineered fit for the extension leads creating a firm mounting. The rudder servo mount wasn't tied into the fin structure which created lots of movement on the fin when the rudder was under load. I made some ply parts and tied them into the aft fin spar making the whole structure rigid when under load.
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Old 12-08-2011, 12:43 AM
  #61
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Default RE: A4 Skyhawk build

and because I have nothing better to do... I do really rate the gear on this model. Skymaster may not be everyones favourite but the gear they make for the higher end kits are up there with the best IMO.

http://www.youtube.com/user/TLJC1?fe.../0/FtE_V3rIhGs
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Old 01-15-2012, 12:12 PM
  #62
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Default RE: A4 Skyhawk build

Hi Alex,

i thought i bring this thread up again since i aquired one of these kits!

I had sent an email here through RCU, but i am not sure if you got it?

Any help would be much appriciated

Cheers

Thomas
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Old 01-15-2012, 12:58 PM
  #63
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Default RE: A4 Skyhawk build

Hi Thomas

Sorry I missed your email, my RCU account is linked to an old address...

If you need to mail me try the email thats on my signature 'thelittlejetco@me.com' I'll always be happy to help where I can.

In answer to your questions I haven't started the installation yet so haven't got anything to show................as its my own model it goes to the back of the line while I do customers toys which are eating up most of my spare time at the moment my main job is getting busy meaning I have even less time for my own stuff.

Cheers, Alex
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Old 02-23-2012, 12:13 PM
  #64
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Default RE: A4 Skyhawk build

I'm starting to pick a bit of momentum up again and having just ordered a new turbine I have no more excuses....

I ordered lots of the missing scale parts from SM and I fully expected to be invoiced but to my surprise all the bits arrived on my door step in late December free of charge! Thanks for the Christmas present Skymaster.

There are a few problem areas on the wing, for instance the carbon spars slot into some epoxy/glass tubes but the front tubes aren't tied into the structure and look like some of the supporting structure has been yanked out but as I said this model is a pre production prototype and has had numerous owners before me so I don't know who has done what. I'm going to have to tie the tube in and repair/reenforce the whole area but at least the rest of the wing is sound. Having looked at the wings and decided they were going to be a major PITA I decided to waste some time sticking the model together for a little inspiration.
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Old 02-23-2012, 03:52 PM
  #65
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Default RE: A4 Skyhawk build

Hi Alex. The tubes are usually just Guide Tubes. The strength comes from the plywood ribs that the spar passes through. I think you will be ok. I love A-4's. I may end up with a Skymaster A-4 some day
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Old 02-23-2012, 06:51 PM
  #66
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Default RE: A4 Skyhawk build

Gents, on my little YA A-4 I also had four hatch latches on the top hatch. I made these handy little wooden pieces to hold the latches open so I could remove/replace the hatch easily. I never got around to painting them red with "remove before flight" on them, HA! You could also attach them all together with string so you don't lose one.

Just a thought.

P.S. - Your A-4 looks fantastic. I always wanted to build a bigger one. Good luck and keep us updated.
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Old 02-24-2012, 08:47 AM
  #67
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Default RE: A4 Skyhawk build

Quote:
Hi Alex. The tubes are usually just Guide Tubes. The strength comes from the plywood ribs that the spar passes through. I think you will be ok. I love A-4's. I may end up with a Skymaster A-4 some day
I'm most likely being paranoid but what I failed to show or articulate in the last post is that the spar only goes through the root rib. The spar doesn't reach the second rib just butts up against it. The front spar is really just an anti rotation peg as the main spar runs through most of the wing but it still doesn't feel me with a warm fuzzy glow when I look at it especially as theres a distinct absence of glue

Good idea with the catch pins, thanks.

Cheers, Alex
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Old 02-25-2012, 12:51 PM
  #68
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Default RE: A4 Skyhawk build

Hi Guys, Hi Alex,

as my A-4 is coming closer to the finish line - i thought i should share some pictures with you!

I still got enough work to do, but she is coming along nicely

Cheers

Thomas
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Old 02-25-2012, 12:52 PM
  #69
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Default RE: A4 Skyhawk build

two more

More to come as progress is made.

Cheers

Thomas

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Old 03-10-2012, 12:06 PM
  #70
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Default RE: A4 Skyhawk build

Hi Thomas

Looking good! Is that fluid in the airline in pic 1 going to the single action valve?

Haven't got much to show with mine, just some very boring structual improvements to the wing and adding gear door detail as mine are just plain layup doors, also having fun with the air rams for the gear doors all sorted now (I hope).

You must be finished yours by now?

Cheers, Alex
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Old 03-10-2012, 01:53 PM
  #71
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Default RE: A4 Skyhawk build

Alex, would like to see what you've come up with for main door operation. I have Pablo's A4 and have been working on main door fix to prevent opening in flight. Post some pics pleeeaassseee.
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Old 03-10-2012, 02:07 PM
  #72
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Default RE: A4 Skyhawk build

I've just been talking to Alex, he's off to bed, early start in the morning but I know he was not happy with the original ram/hinge geometry.

Gary.
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Old 03-11-2012, 11:17 AM
  #73
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Default RE: A4 Skyhawk build

Hi there, I'll get some pictures in the next few days for you.

Basically I've got a two inch stroke ram on the doors and put magnets on each corner and a spring on the ram to help hold it down once closed as the geometry isn't correct but it never will be because of space we have to work in. The ram can't overcome the force of the spring and magnets once closed again because geometrically it's in the wrong place. I've teed a small 1 inch ram into the door down line and gear up line, this pops up and pushes the door open about 5mm then the main ram does the rest. It will make more sense when you see the pics.

Hope this helps in th mean time.

Cheers, Alex
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Old 03-12-2012, 05:15 AM
  #74
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Default RE: A4 Skyhawk build

Alex, Pablo had tried the earth magnet to no avail, but without the helper spring, Here is what I've come up with, a motion transfer arm and mount. Now the air cylinder side to side moves the door actuator rod vertically. the adjustment holes and rod length will allow the linkage to travel over center in the open position to provide positive opening lock(the air cylinder at full exstension and positive closed lock with the door linkage arm in a line with the transfer arm pivot point. Any thoughts, thanks, Steve.. BTW the door cylinder has to be replaced with a 1.5" stroke, this is the one originally installed and everything is just tacked in place for now
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Old 03-12-2012, 05:56 AM
  #75
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Default RE: A4 Skyhawk build

Nice work! Hope it solves the problem for you. I've always found gear door problems to be very trial and error, just give it a go and see... How much better is it when you try and pull the door down by hand?

My solution was to use these small 5mm Neodymium magnets which are very powerful. Once the door is closed its hard to open it and the ram doesn't stand a chance especially with the spring holding the door. The smaller ram lifts the door by 10mm which is enough to release the magnets and it pops open, hopefully it will work but I'll only know for sure once its flying. All I have to gauge it by is that its far more powerful than the stock set up was at holding the door.

Cheers, Alex
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