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"Ms Jax" - free plan back in the late 80's??


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I still have a bit more work to do with the Solartrim, but haven't quite made my mind up on the final design yet. I'm not going to be ready to maiden it tomorrow as I've still got the controls to connect up and set up yet.

Hopefully I should be able to get it finished sometime next week... watch this space.

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Thanks guys... I always find the covering hard work, especially with those complex curves, but have to admit that it looks quite smart, in the photos at least (where you can't see all the wrinkles) wink

Next up is the maiden which I'm a bit nervous about... I've never maidened a model before... I've always had someone more experienced do it for me, but am quite keen to do this for myself.

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In essence Colin, nothing more complicated than measuring the key dimensions from the original plan, reducing them by 20% and re-drawing it onto a length of lining paper. However, as it was also an IC to electric conversion, I had to re-design the front end internals a bit (ie. bring the bulkhead forward and add a battery tray). Obviously it wasn't possible to reduce the material thicknesses by exactly 20% so most of the thinner materials remain as per original plan, but I was able to knock off the odd 1/16" or so from some of the thicker components to keep the weight in proportion.

For the wing ribs, I scanned the relevant part of the original plan onto my PC, reduced it down in Photoshop and printed it out which worked pretty well.

I found a nice piece of free CAD software from Siemens which I used to draw up and print out the formers, etc. but this could have just as easily been done the same way I did the main plan.

dsc_0212.jpg

ms jax wing profile.jpg

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Everybody eventually gets to the point where they realise they should do their own test flight rather than relying on the club expert.

I would offer a few suggestions for this:-

1. only do a test flight when conditions are ideal and preferably with no other models flying at the time. Let everyone know you are doing a test flight & ask your fellow fliers to stay grounded for the 5 minutes or so.

2. If the club expert offers to do the test flight say no I want to do this myself but please stand by to offer advice if needed. Have another pilot ( who flys the same mode ) to move the trims if required so you dont have to move your thumbs off the sticks. The other pilot should be someone you trust to give good advice if things get hectic or the plane goes too far away.

3. Have a couple of flights first that day on another model.

4. Obviously do all the usual preflight checks ( a written checklist may help) and ensure all the control surfaces look dead level ( Very important!) yet still have plenty of trim either way if needed. Make dead certain you have the right model memory selected if it's a non model match TX.

5. Enjoy it and steel yourself that if the worst happens maybe nobody else could have done better!

6. dont hesitate to call it all off if anything is not perfect or the weather deteriorates, but equally make sure you dont put it off unnecessarilly.

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Scaling plans up or down.

I use a calculator with the scale factor put in as a constant ( varies but often pressing " x " twice does this ) so then all you do is put in the length and the new length is shown. Measuring in millimetres seems much easier even if you normally work in imperial. ( not many inch rulers have tenths all along, only just a small bit which suddenly changes to eighths or something which catches you out). Everything can be measured from a datum line. Any angles can be measured with a protractor or better with a carpenters bevel gauge or homemade equivalent. If using a drawing board & Tee square then its easier to use the tee sq from the top of the drawing board ( not the left side as normal) as almost all the important things are vertical ( formers etc) and very little is horizontal except the datum line.

I always make a master wing rib outline ( including wing sheeting) from ply and all the drawings and rib shapes are done using this.  Actual cutouts for wing in the balsa fuselage sides use this too.  They are then all the same even if the outline is not quite the same as the original plan.

Edited By kc on 03/09/2014 11:46:41

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Thanks for your advice on test flights kc. I'm not currently a club member, but have had great help with maidens from my LMS in the past. I did take the new model out this morning, but it was looking just a little too windy for my liking... it was definitely the right decision to abort as it's got windier and windier as the day has progressed.

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One thing I didn't mention was rate switches - good idea to have reduced aileron and elevator movements setting available if required. Especially for an untried design or size. ( some may suggest having greater movement available but I reckon reduced is more important to help tame an unruly model )

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Hi Gary, I don't currently have a comprehensive plan as such - just a working (outline) drawing which is now a little worse for wear, having been used for the build. I do have a few detail drawings (electronic format) of the internal formers and the tailplane which you are welcome to have and, if the plane flies ok, I intend to draw up a proper plan for reference, should I need to repair or build another. I'm going to try doing this electronically and produce a pdf.

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I'm happy to report that I maidened Ms Jax today and am really pleased with it. After six take-offs and the same number of landings, it's still in one piece!! smile d

It certainly has a "spritely" performance with the chosen power train.

I will try to post a bit of video footage later...

Gary / Jack, I'm working up a proper drawing and you're both welcome to a copy once I've finished.

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Here's some footage of the initial flights... unfortunately I had no one to operate the camera so it was just stuck on a mini tripod, pointing in the general direction (can't believe that there was nobody else at the park yesterday despite perfect conditions!).
 
 
Hopefully it will give some idea of how the model flies... best viewed at 1080p and full screen if possible as the plane spends a fair bit of time in the distance. Hopefully I'll be able to get some better footage if I can grab a helper next time out.
 
 

 

Edited By Mike Smith on 06/09/2014 09:40:31

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