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Member postings for Max Z

Here is a list of all the postings Max Z has made in our forums. Click on a thread name to jump to the thread.

Thread: The Atom Special
29/10/2014 16:10:03

Hurray! Two more flights today, still in one piece! I think there's a lesson there, don't make that third flight! wink 2

She wants to drop out of the sky when banking too much, resulting in some scary moments and over-compensating but I learned that if you let go of the right stick when she is anywhere near horizontal she will stabilize nicely by herself. I did record it on video, but the result is not worth compiling and showing. For one thing, I should have switched off the auto focus to stop it going out of focus all the time. And a far off object (I tried Rich, honest!) against a grey sky, jumping about the screen is not fun to watch.

I think I am getting the hang of taking off. Still not a lot of wind today (Bft. 1 or 2 at the most), but holding back the stick while moving at a slow pace will rev up the rotor nicely, opening the throttle and letting go of the elevator stick gradually will result in take off in 15 to 20 meters. 


Edited By Max Z on 29/10/2014 16:18:38

29/10/2014 12:35:54

Thanks for the encouragements guys.

Posted by Richard Harris on 28/10/2014 17:55:46:

the best piece of advice as you move forwards is....keep it at close quarters as much as you can wink 2


Rich, if you read my "crash report", you will notice that that's what got me into trouble in the first place! wink 2

Just kidding, I understand what you are saying. I am glad I followed Chris' example and made the top of the blades a bright colour, so I can spot excessive banking at a distance (only when turning towards me ofcourse, but that's what you do when it gets too far away).

Repairs have been done, but today is gloomy and still, so I probably will not try again today and fall into the trap of needing a long takeoff run and getting too far away. And yes, I know i've said it but I could not resist beautifying the new rotormast cheeky.

About a video, I will see if I can muster a cameraman, but publishing it will be a first for me.


Edited By Max Z on 29/10/2014 12:36:29

Edited By Max Z on 29/10/2014 12:37:06

28/10/2014 15:49:33

Today's adventures: conditions were quite good, more wind than last time. The rotor could be spun up while standing still and pulling the stick back, so stick back to neutral, open throttle and up and away she went! Made two flights without major incident, just a topple over at the second landing due to catching it too soon. Went up for a third flight, all was well so I decided to do a nice low and slow flyby. Everything was ok but I drifted a bit and before I knew it I was flying straight into the (by then quite lowish) sun. I could not see a thing for a few moments, just long enough for losing control and smashing into the ground sad.

Damage is not too bad, less than last time actually. Broken prop, bent LG leg and a broken mast (again angry 2!). I will shortly start manufacturing my third mast, but I think I will forego the nice streamline finish this time.

She's a good flyer, I will just have to learn to use those rudders more often.


Thread: Whippitt dummy radial engine
28/10/2014 09:43:00
Posted by cymaz on 20/08/2014 21:02:11:

Does it look like this

That's it! I will just double up my Anzani dummy.................


Sorry guys, could not help showing it d


Thread: The Atom Special
26/10/2014 12:42:34


I would have done such trimming hops, but due to the lack of wind I needed a fairly long run before I felt certain that the blades had come up to take off speed, and by the time I was committed to flight I was running out of runway. So the only way was up, and I tried to make a gentle circuit to get back to the field for landing. With the result as above. Oh well...back to the workshop. At least I did not break one or more blades, as I am not looking forward to making and balancing a new set. (I should have taken notes of the weight and balance point before covering sad


Edited By Max Z on 26/10/2014 12:46:07

25/10/2014 16:27:11


Okay, maiden flight today. First I made sure that everybody present could identify the aircraft wink:


The weather was overcast, with just a hint of wind. I started with a couple of roll test to see if the rotor speeds up. This seemed to be the case, especially when heading into what little bit of wind there was, luckily it was blowing straight down our strip. It toppled over a few times when I tried to turn into the wind at speed, but the blades neatly gave way on impact, swiveling back on the rotor plate.

When I felt that the rotor sped up sufficiently and was not accelerating anymore, I decided to take the plunge and press on with the takeoff. Taking off it did, albeit somewhat wobbly (pilot induced oscillation I guess...) and I managed to keep it under control for a while. I think I lacked the coordination to turn the Atom properly to complete the circuit, and it did get rather far away from me. What followed was what you probably expect, loss of control and an all too quick return to terra firma ( in the guise of the rather wet plowed field that borders to our patch).

The damage was not too bad, broken prop and ripped off front decking (to let the battery past...sad). Most involved repair action will be a replacement rotormast since it snapped off where it exits the fuselage. Luckily I made it removable, so it should not be too hard to dig the remaining bit out.

All in all, not a complete success, but it is certainly capable of flight. I have one comment on the design, I think the rudders are too small. I had trouble steering it on the ground (mind you, the grass was quite long today, wet weather over the last days prevented mowing which is normally done before every weekend), but in the air I also felt I missed a bit of rudder action. But it was my first single rotor gyro experience, so I could be wrong.


Edited By Max Z on 25/10/2014 16:35:42

Edited By Max Z on 25/10/2014 16:58:36

24/10/2014 13:20:09
Posted by nigel simkin on 17/10/2014 18:05:31:

If I make the gap 14mm then I will only have this small section (the black triangle on photo) touching the blade holder is this correct?root.jpg

I was a bit worried about that too. Moreover, if the shim is anything less than 6 mm wide, and the blade is forced to veer forward ( in a bad landing for instance), the shim will slip off the triangular plate. By readjusting the blade to its position it will then be forced on to it again which is not desirable. I made mine a 8 mm wide strip of plywood which I tapered to a wedge by sanding it with the LE as a guide.

( I used a blade width of 52 mm like Steve did, so I also opted for a 0.8 mm shim thickness)


Edited By Max Z on 24/10/2014 13:20:53

23/10/2014 16:10:19

After balancing and covering the blades, it is READY TO GO! Well, almost. I still need to get me some selflocking nuts to avoid seeing the rotorblades flying away in the sunset.......



My take on the rotorhead:


And this is how the cockpit turned out. Actually, I think it is not too bad. The pilot is a cartoon character from the 70's/'80's, who was always tinkering with stuff and creating new 'inventions', most of them useless but great fun:


22/10/2014 19:48:41

Watched that video.... I hope that I can avoid most of that knowing what I know now thanks to you guys!

I am about to start covering the blades, and I was wondering if there is any merit in selecting contrasting colours for top and bottom to assist in recognizing flying attitude. I plan to do the top in a bright yellow fluo colour, but I am hesitating what to use for the bottom, white or a dark colour. Any thoughts?


21/10/2014 21:11:35

Steve, is it really required to have the LE razor sharp? I am used to rounding it, and I guess I just could not resist.....


Edited By Max Z on 21/10/2014 21:11:54

21/10/2014 20:24:25

Progress has been slow for me. I have been struggling to make a decent cockpit for the Atom. I tried the balsa-block-in-a-bottle-trick. Two bottles have been harmed in the process without result. I just did not seem to be able to shrink the forward part around the block properly. It kept curling up without fitting. When the balsa started to scorch I gave up. I used a transparent sheet I had lying around instead, fixing two battens on either side, heating it and pulling it over the block. I will spare you the stories about wrong glue, wrong trimming foil. I will show you the result sometime and let you judge the result.

On to the rotor blades. I thought I would show you my planing/sanding method. Like Richard described it ( or was it one of the Stephens? ), I planed wedges off from the leading and trailing edges. I then made up a little tool into which I fed the rough blades, and used a sanding block to sand the final airfoil in 3 or 4 places. As you can (hopefully) see, the sanding depth is restricted by the curved sides of the tool, and the "wings" (I don't know another word to describe them) formed by the plate screwed to the top of the block. I then used a sanding bar to finish the blades, just sanding until you see the indentations from the cross-sanding in the tool disappear.

Let the pictures speak for themselves:






Edited By Max Z on 21/10/2014 20:26:22

Edited By Max Z on 21/10/2014 20:28:58

Edited By Max Z on 21/10/2014 20:29:39

17/10/2014 14:38:27
Posted by Richard Harris on 16/10/2014 22:38:14:
Trim the end of the blade so that you have roughly a 14mm gap between blade root and blue triangular bearing housing.
Posted by Steve Jones 2 on 13/10/2014 21:13:34:

So, my Atom blade dimensios are:

Length - 445mm

Width - 52mm

Bolt mounting - M3 at 20mm from blade root

I am getting confused here, both pieces of info are conflicting. I had to guess at the size of the bearing housing since I do not have the HK head to measure, but with the position of the holes as per the published drawing it can hardly be any smaller than what I drew in this sketch:


This results in a blade bolt position of 10.5 mm from the root, not the 20 mm that Steve mentions. Where did I go wrong?


Edited By Max Z on 17/10/2014 14:41:15

16/10/2014 21:25:51
Posted by Richard Harris on 16/10/2014 20:58:52:

From F3 it roughly balances at around 50mm forward of this

Thanks Rich. Mine balances a bit further forward, about 55 mm from F3.


16/10/2014 17:57:01

I did the "hanging test" today, with everything on board except for the rotor (I figured since it will be symmetrical around the tethering point it will not influence the hanging-angle). I am finding that the angle is right up to the maximum of 18 deg.

I did use a slightly heavier motor than the one proposed in the instructions (a Turnigy SK3 2830 series rather than a 2826), about 13-14 gram difference. For this reason I moved the bulkhead some 10-12 mm back, and put the motor hard against it. Prop is an APC E type, 10x5. Battery is a 1650 mAh 3s, I moved it right back in the cockpit area.

The only conclusion I can draw is that I built the tail too light . What should I do best, go with it or add some weight to the tail to move the CofG backwards?


Edited By Max Z on 16/10/2014 17:57:38

Edited By Max Z on 16/10/2014 17:58:05

15/10/2014 19:25:12

Go right ahead Terry, but do note that it has not yet been proven in service. And you should know that I shortened the control bar by 5 mm on both sides later to get the required roll movement. This is a recent picture:



Edited By Max Z on 15/10/2014 19:31:45

Edited By Max Z on 15/10/2014 19:37:39

Thread: Direct linking to individual posts?
15/10/2014 18:31:51

Thanks Phil!


15/10/2014 18:02:57

Is there a way? Posts are not numbered either, making it cumbersome to refer somebody to them: "My post of date x, time y in thread z......"


Thread: The Atom Special
15/10/2014 17:19:03
Posted by nigel simkin on 15/10/2014 16:52:15:
Hi Max, what head have you used on yours?

That is a cut-down and modified Aeronaut gearbox (which I posted earlier):



Edited By Max Z on 15/10/2014 17:19:30

15/10/2014 16:50:22

Hi Terry,

The mast is a 10x6 mm plywood strip, the protruding bit has been padded with some balsawood and sanded to an aerofoil shape. The lot is covered with aluminium coloured Oracover film.


Edited By Max Z on 15/10/2014 16:50:57

15/10/2014 12:39:56

My Atom is coming along slowly but surely:





Edited By Max Z on 15/10/2014 12:40:50

Edited By Max Z on 15/10/2014 12:43:34

Edited By Max Z on 15/10/2014 12:44:22

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