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Old Oct 31, 2012, 05:02 PM
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FunPilot's Avatar
Japan, Miyagi Prefecture
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Well, my Acromaster arrived yesterday, right on schedule, and I have the motor and servos on hand, so now it's just a matter of finding the time to sit down for the build. I want to do this one nicely, so I won't rush. In fact, I'll relish every moment.

Didge,

Thanks for the info. 1,869 grams of thrust, eh? That should do it. I should probably take it easy with the ol' throttle thumb for a while, I guess.

Rob,

Thanks. Do you have a photo of that brace you glued under the motor mount? It might be useful to know how big it is and where it's glued in. I'm hoping I don't have to deal with vibration problems, but you never know.
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Old Oct 31, 2012, 09:29 PM
A geriatric flier
Watdazit's Avatar
Australia, NSW, Braidwood
Joined Nov 2008
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Quote:
Originally Posted by FunPilot View Post
Well, my Acromaster arrived yesterday, right on schedule, and I have the motor and servos on hand, so now it's just a matter of finding the time to sit down for the build. I want to do this one nicely, so I won't rush. In fact, I'll relish every moment................Didge,
.
I found it a fairly straigh forward build but here are a couple of pointers.

Be careful pushing the elevator and rudder servos into place. There is a small block of foam behind each servo lug and I found to my annoyance they are easily broken off.

The decals are nice. Make sure where they finish on the leading edge of the wing and elevator wing that you leave enough of the clear plastic on so you can wrap it around the leading edge and not finish on the edge. There are injection moulding dimples all over the plane and these are a pain in the neck when trying to get the decals laying flat. I tried sanding them off using the canopy as a trial but this was not successful. Perhaps someone might have a better method.

The diagram for glueing the two wing sections together talks about putting a foam block under the leading edge. I did this by firstly weighting the outer ends of the wing down so the the trailing edge of each wing where the ailerons fit was flat on the bench. I then put the block in place making sure it did not lift the wing but only stopped the wing being pushed down when you fit the two halves together.

I have yet to fly mine. I finished it a couple of nights ago but at present the wind is howling.
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Old Oct 31, 2012, 09:49 PM
Takeoff=Option Landing=Must
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USA, NY, Depew
Joined Jan 2009
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FunPilot,
First pic is from Gemini, but its the same idea, second pic shows from outside where the dowel goes.
To this day I don't have mooing issues and the plane logged in lots of time.
I tried balancing all moving parts, metal motor mount, stiffening of motor bay and they where temporary fixes.
Between all my multiplex (gemini, acromaster, dogfighter, funcub) and wing maker planes (sunrise, handyman) I developed this simple working solution.

One thing I learned on AcroMaster is to think ahead. Plane will continue last maneuver. You have to counter act when you are done with what you just did.

After you get good at it, true 3D bird will be easy.
Have fun. This plane is tough. I stripped 3 out of 4 metal gear servos, I ripped out horns, I nosed it in few times, broke landing gears and is still going.

Rob
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Old Oct 31, 2012, 10:29 PM
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Japan, Miyagi Prefecture
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Rob,

Excellent! That shows the size and positioning of the brace very well.

Thanks!
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Old Oct 31, 2012, 10:30 PM
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Japan, Miyagi Prefecture
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I have yet to fly mine. I finished it a couple of nights ago but at present the wind is howling.
Thanks for the tips Watdazit.

Looking forward to the movie when you get it in the air!
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Old Oct 31, 2012, 10:47 PM
A geriatric flier
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Australia, NSW, Braidwood
Joined Nov 2008
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I also fitted a ply brace between the plastic motor mounts. Mine was slightly different and if I get a chance I will see if I can photograph it.What I did is glue 2 pieces of 2.5mm ply 30mm long and 10mm wide to the plastic mounts on either side to form a slot either side which lined up with the slot in the plastic brace they supply. I then glued a piece of 2.5mm ply about 30mm x 40mm (the width between the plastic motor mounts) into the ply slot and into the plastic brace.
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Old Oct 31, 2012, 11:08 PM
A geriatric flier
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Australia, NSW, Braidwood
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Originally Posted by robusp View Post
FunPilot,
.................One thing I learned on AcroMaster is to think ahead. Plane will continue last maneuver. You have to counter act when you are done with what you just did.....
Rob
This is an interesting observation. I find flying novice F3C with my 700 heli you have to keep thinking what is the heli going to do at the end of the maneuvers so you can keep the lines smooth. (I am not very good at it by the way).
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Old Nov 01, 2012, 03:38 AM
Flyin brick
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Joined Feb 2005
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Try wet sanding with 500-600 grit, u'll love it
Quote:
Originally Posted by Watdazit View Post

There are injection moulding dimples all over the plane and these are a pain in the neck when trying to get the decals laying flat. I tried sanding them off using the canopy as a trial but this was not successful. Perhaps someone might have a better method.
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Old Nov 01, 2012, 05:45 AM
Foam, foam on the range....
didge's Avatar
Adelaide, Australia
Joined Feb 2009
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Try wet sanding with 500-600 grit, u'll love it
A disposable razor works pretty well, too.

Cheers
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Old Nov 01, 2012, 03:34 PM
A geriatric flier
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Australia, NSW, Braidwood
Joined Nov 2008
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A disposable razor works pretty well, too.

Cheers
Wife "What are you doing dear?"
Me "I'm shaving dimples off the AcroMaster"
Wife " Sad, very sad".
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Old Nov 01, 2012, 05:50 PM
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Japan, Miyagi Prefecture
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Wife "What are you doing dear?"
Me "I'm shaving dimples off the AcroMaster"
Wife " Sad, very sad".
Ha!

My wife gave me the "poor, sad man" look the day I started playing with "toy airplanes."

I may be in my fifties, but I still know how to play!*

* And learn ... nyah nyah nyah ...
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Old Nov 01, 2012, 06:13 PM
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Japan, Miyagi Prefecture
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Speaking of learning, I have another question for those of you who are more experienced in the black art of matching motors to airframes.

Check out the specs on these two motors:

1) Hyperion HP-ZS3009-20
Weight: 98.5 grams
KV: 1100 rpm/V
Typ. Current: 18A ~ 26A
Max. Current: 34A
Max. Power: 450 watts
(Prop. data provided by Hyperion: 9540 rpm @ 408 watts with an APC 11x5.5E)

2) Hyperion HP-ZS3014-14
Weight: 126.3 grams
KV: 972
Typ. Current: 22A ~ 36 A
Max. Current: 42A
Max. Power: 600 watts
(Prop. data provided by Hyperion: 9450 rpm @ 345 watts with an APC 11x5.5E)

Also note that both these motors are similar in size to the "standard" Acromaster motor (the Himax HC 3516-1130) and have the same mount dimensions, and both are lighter (the 3516-1130 weighs 134 grams)

OK, here's my dilemma.

I was planning to put motor #1 in my new Acromaster, but have since acquired motor #2 and am now thinking I'd like to put motor #1 in my Fun Cub, which is currently a bit underpowered at 280 watts max., and put motor #2 in my Acromaster. Since motor #2 will give me approximately the same rpm with an 11x5.5 prop as motor #1, just with less power draw, I'm guessing it'll be OK.

Is that a reasonable analysis, or is motor #2 just too much power for an Acromaster?
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Old Nov 01, 2012, 06:54 PM
Foam, foam on the range....
didge's Avatar
Adelaide, Australia
Joined Feb 2009
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Originally Posted by FunPilot View Post
Is that a reasonable analysis, or is motor #2 just too much power for an Acromaster?
As you have said above, using the same prop, motor #2 will actually pull less power than motor #1.

According to Drivecalc, the 11x5.5 at 9450rpm will give 1831g thrust, so you probably wouldn't notice that much difference in flight. Looks very efficient though - if it will really spin the prop at that rpm using only 345 watts, that equates to around 88% efficiency (again according to Drivecalc).

This efficiency rating sounds high, but Hyperion motors are known for their efficiency. Motor #2 will probably be a better match weight-wise too, depending on how much (if any) extra strengthening you do around the motor mount area.

Cheers
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Old Nov 01, 2012, 07:18 PM
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Japan, Miyagi Prefecture
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Originally Posted by didge View Post
As you have said above, using the same prop, motor #2 will actually pull less power than motor #1.

According to Drivecalc, the 11x5.5 at 9450rpm will give 1831g thrust, so you probably wouldn't notice that much difference in flight. Looks very efficient though - if it will really spin the prop at that rpm using only 345 watts, that equates to around 88% efficiency (again according to Drivecalc).

This efficiency rating sounds high, but Hyperion motors are known for their efficiency. Motor #2 will probably be a better match weight-wise too, depending on how much (if any) extra strengthening you do around the motor mount area.
Done and decided! Thanks again Didge.

So now I can boast that I have a 600 watt motor in my Acromaster ... ... even though I won't actually be using anywhere near that much power.

I'm sort of hooked on Hyperion motors at the moment, partly because I have a source where I can get them relatively inexpensively, and partly because they really do seem to have an efficiency edge. They're also beautifully made little gems. The newest models in particular seem to be smaller and lighter than average for the same power. And no, I'm not affiliated with Hyperion in any way.

I'll let you know how it goes when I eventually get the thing flying.
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Old Nov 01, 2012, 11:19 PM
A geriatric flier
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Australia, NSW, Braidwood
Joined Nov 2008
850 Posts
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Originally Posted by FunPilot View Post
Ha!

My wife gave me the "poor, sad man" look the day I started playing with "toy airplanes."

I may be in my fifties, but I still know how to play!*

* And learn ... nyah nyah nyah ...
50's! Mate I'm 70 and retired and any of my friends who thinks planks and helis are toys then I offer them an MSR heli or a micro Trojan to have a go with for a while. That shuts them up especially when I suggest they pay for the damage.
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