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martynk
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« on: February 09, 2024, 04:58:19 PM » |
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Last week, I did a club presentation on small field free flight comps. Looks like they have bitten as we are running 3 classes, 36" hi start glider, kk Playboy 20" span as a one design rubber class and e20 for electric power duration.
As a preliminary activity, I redrew the parts sheet using AutoCAD as the original KK copy that I had was certainly on the rough side.
Thought I had better make a start on the Playboy. So, a couple of hours in the workshop and a wing has started to appear. Damned pixies at it again..
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Martyn
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cvasecuk
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« Reply #1 on: February 09, 2024, 05:01:59 PM » |
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The Playboy has an undersized fin. It needs an extra 2sq in to fly well.
Ron
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martynk
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« Reply #2 on: February 09, 2024, 05:06:50 PM » |
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Yes, I heard the same from Andy Sephton. Apparently the model as drawn has a tendency to Dutch roll. I'll increase the height and depth of the fin.
Thanks
Martyn
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« Last Edit: February 09, 2024, 06:39:54 PM by Ratz (Bruce) »
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Martyn
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martynk
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« Reply #3 on: February 09, 2024, 05:12:26 PM » |
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I forgot to mention.
The parts sheet was printed using a laser printer. This gives two easy options to transfer to balsa, either iron the image down and the heat with soften the laser ink and transfer or alternatively, lay the paper down on the wood and rub a solvent through. I used cellulose thinners. It took about 2 minutes of rubbing to get a nice easy to read but un-smudged transfer. Sadly, it doesn't work with ink jet printers.
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Martyn
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Slowmatch
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Jon Whitmore
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« Reply #4 on: February 09, 2024, 05:36:07 PM » |
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Nice one on the FF club activity Martyn. I built a Playboy a few years back, it was never a duration model exactly, but I do remember it doing over a minute in lift once or twice. I used an acetate trim tab to increase the fin area.
Jon
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martynk
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« Reply #5 on: February 09, 2024, 05:45:59 PM » |
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Thanks Jon
I have to admit that I recycled the Peterborough Small Field rules rather than start from scratch.
Not looking for out and out duration, just to have a bit of fun. If it goes well then I'll suggest we use P20 rules next year. The field isn't huge, School upwind and houses down one side and trees in the centre. A FF nightmare. Probably go for precision duration unless its absolutely flat calm.
Thanks for the tip on increasing the fin area. I'll pass that on..
Martyn
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Martyn
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martynk
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« Reply #6 on: February 12, 2024, 05:12:33 PM » |
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A little bit of progress. Noyt much as I spent the back end of last week preparing for the BMFA NW Area indoor gala and the last couple of days doing minor repairs.. Ho hum.. The wing halves got joined with the correct dihedral and the spar and centre rib added. Gentle sanding gto get the le profile and its almost ready for covering. This evening , I framed up the tailplane. May get the enlarged fin done tomorrow. I waa going to fit a dt, but I am certain that its really necessary - unless I can be persuaded otherwise..  -- Martyn Keil Kraft Playboy |
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Martyn
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martynk
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« Reply #7 on: February 12, 2024, 05:14:17 PM » |
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And the second photo  -- Martyn Keil Kraft Playboy |
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Martyn
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Arnold S
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« Reply #8 on: February 12, 2024, 06:09:05 PM » |
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The Playboy has an undersized fin. It needs an extra 2sq in to fly well.
Ron
Plus 1 on this. I plan to put an underfin on mine, as there is no tail skid as such so it serves both purposes… Andrew |
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I’ll be back…
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martynk
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« Reply #9 on: February 29, 2024, 05:01:32 AM » |
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Apologies, I have been crawking along wuth this for a couple of weeks and forgot to update. Its just about finished, weight is 25.4g shich is a bit porky. Hope to maiden at an Indoor event this weekend. I have enlarged the fin as suggested, the prop is an igra and the wheels are 3d printed     -- Martyn Keil Kraft Playboy Keil Kraft Playboy Keil Kraft Playboy Keil Kraft Playboy |
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Martyn
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martynk
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« Reply #10 on: February 29, 2024, 05:08:27 AM » |
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One bare bones photo
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Martyn
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