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#1 JeremyBB Mar 05, 2012 03:31 AM

Hovercraft SR.N6
 
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Build logs of scale hovercraft appear to be few and far between. So I've decided to start one here of my 1/16th scale SR.N6 built to a plan designed by Mark Porter. Any comments, help advice etc that I can get along the way would be much appreciated :).

I plan to model the Hovertravel version shown in the photo below. I have started construction of the basic shell using 0.8mm birch ply and 6mm square balsa strips. So far, so good...

#2 ChrisCurry Mar 05, 2012 04:10 PM

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Looking good! Nice ribs. I cheated with the ribs and just cut a hole in each one.
Made the ducting by wrapping balsa around a jam jar. Managed to sand the inlet so it looks even.
I painted the fan and ducting as it's probably easier to do during the build and touch up at the end. What are you using for the lift?

#3 JeremyBB Mar 05, 2012 05:05 PM

Mark Porter's original design used a standard 540 brushed motor for lift with a 3 bladed 6"x3" prop.. I will use a brushless motor for more power and less weight but will stick to the same prop. The hole in the base is 6" in diameter so I may have to trim a prop a little bit. I haven't chosen the motor yet nor have I decided how to mount it to the body. When I get a bit further on with the build, I will have to work it out.

From your photo it looks like you are using an impeller for lift. How do you see that working as compared to a propellor? It's reduced diameter certainly gives you a more prototypical appearance.

I look forward to following your build.

#4 ChrisCurry Mar 06, 2012 03:33 PM

I am using an impeller as it gives a more scale appearance and apparently has more of a compressor effect than a propellor. Also I just wanted to see if I could make one :)
I think the brushless and a prop will be a lot more efficient than the old rs540. Looking forward to more pics. I'll post some more of mine if I may as I've got quite a bit further.

#5 ChrisCurry Mar 08, 2012 01:09 AM

A big advantage of the impeller/centrifugal fan. I've finished the skirt and attached it using tape so i can test it. It hovers on about 10% power! I'm using about a 100w motor so that's pretty efficient. It does weigh in at about 1kg so pretty light so far.

#6 ChrisCurry Mar 10, 2012 04:16 PM

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Moving on quicker now. The thrust motor had its shaft removed and I found a piece of 3.2mm piano wire which fitted it just fine. A few support bearings later, I wrapped the lot in .6mm ply.

#7 owlsabie Mar 14, 2012 11:23 AM

Hey Chris - looking great there, so glad your impeller works:D Looking forward to seeing this one in person again

Al

#8 JeremyBB Mar 17, 2012 06:18 AM

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Hi Chris

You are making great progress. How were you able to test the lift of your model before sheeting in the deck?

My removable cabin structure now complete. Next step will be to install the peripheral support for the side frames. I will use 1/4 inch square spruce for this - heavier than balsa but it will provide better protection against the inevitable bumps.

Jeremy

#9 ChrisCurry Mar 19, 2012 02:10 AM

I didn't test the lift but merely spun up the fan in the housing that I made for it. It blew everything off of the table so I knew it would work OK. In practice it works brilliantly. It hovers on less than half power and consumes less than 50 watts!

Your build is looking a lot nicer than mine. Your windows look really good.

#10 ChrisCurry Mar 26, 2012 03:15 PM

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Moved on. Have hovered and it does hover well at low powers.

#11 owlsabie Mar 27, 2012 09:48 AM

Hey Chris ! She's a beaut!! Any news Jeremy?:popcorn:

Owl

#12 ChrisCurry Mar 27, 2012 12:22 PM

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Thanks, owl. I've just taken another picture now that the prop been replaced and the back end rebuilt. You can see that the panier lid back left is missing. That's the one that opened mid "flight" and broke the prop and did the damage.

#13 ChrisCurry Mar 27, 2012 12:31 PM

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Here is the kit I'm building for my daughter. The fan has come out far better than mine. I might steal it :) you can see bottom middle my special tools - the blade angle thing on the left, the blade length cutting jig in the middle and the window cutter on the right. Two hovercraft at the same time works quite well.

#14 JeremyBB Mar 28, 2012 02:11 AM

Hi Chris.

Beautiful model and you seem to work at the speed of light - from basic structure to close on completion in only three weeks! Will you be adding the ribs to the deck? Nothing to report on my build, Owl, as we've been away on holiday. I'll get back to it this weekend.

Jeremy

#15 ChrisCurry Mar 30, 2012 02:07 AM

I will be adding ribs and puff ports to the deck. Hopefully get them to work as well. Busy closing up the area around the thrust motor. Bit of a pain...


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