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Old Jan 09, 2009, 04:59 AM
I'm torquing to you!
Mr Kamikaze's Avatar
Wattle Grove NSW Australia
Joined Nov 2006
7,369 Posts
Quote:
Originally Posted by Mr_Cash
Steve,

Ask Mr. K, what his good flight cg was.

I.e., how far back, from the leading edge of the wing, measured near the fuselage, is the center of gravity that gave him a good flight?

Position of battery, and battery weight and/or size type (factory battery?), and if any weight was added to get his cg.

Also, ask the neutral trim position settings were, for the rudder (perfectly straight?), elevator (perfectly flat zero?), ailerons (perfectly straight flat?), or any other things he did, such as mixing of ailerons & rudder and such (I have never had ailerons, and know nothing about mixing, so any basic "how to" instruction appreciated), that I saw commented on earlier in the thread.
Hey guys

The CG is as per recommendations. That is 5mm forward of the front line on the bottom of the wing. To get this I have the battery set sideways in the bay and as far forward as I could get it like that, then just in front of it I added a 25gram slug of lead. All trim settings are neutral and there is no mixing. Though I do "fly" some rudder with the ailerons in the turns. I just prefer to do it manually rather than a mix. The only thing I would say against it so far is the roll rate is slooooooooooooooooooooooow. But I mainly want it for thermalling so flat turns are ok.
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Old Jan 09, 2009, 05:18 AM
Nup, I got nothing!.....
evo62's Avatar
Gold Coast, Australia
Joined Jun 2007
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Mr K,

Do you mean the tape on the bottom of the wing? I used the middle of the tape - ie the carbon spar. Figures my CoG is too rearward.

Clovus
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Old Jan 09, 2009, 05:47 AM
I'm torquing to you!
Mr Kamikaze's Avatar
Wattle Grove NSW Australia
Joined Nov 2006
7,369 Posts
Quote:
Originally Posted by evo62
Mr K,

Do you mean the tape on the bottom of the wing? I used the middle of the tape - ie the carbon spar. Figures my CoG is too rearward.

Clovus
Yep the front line of the tape. Not the spar.
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Old Jan 09, 2009, 05:49 AM
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Mr. K,

To verify,

1) you used the factory 1000 mah lipo 2s battery?

2) to clarify/confirm a good working cg, ... could you measure your CG, from the leading edge of the wing near the fuselage, to your CG point? And, this seemed a good/optimum cg spot for good flight?


Will it climb vertical? And/or, how long, may it take, to get to about a 1000 feet up (to glide down motor off from there)?

What do you estimate, flight time on one 2s factory battery, in a non-slope area?

Since you added weight to get your cg, any interest in trying a more powerful heavier 3s lipo, that would allow not using the extra lead weight for the cg, to see
a) if the stock motor & esc can handle it without burning up?,
b) if the 3s would allow it to better climb vertical?, and
c) if it keeps its good thermal & flight properties with the 3s?

Thanks.

Late addition: The ST ASW28 manual, page 8 (online) does suggest using the "line" on the bottom of the wing as a reference point.

The part about "adding 5mm to that line forward", the print is so small, I cant make that part out. But as Mr K says, its the line, not the spar, as the starting point to get to the right cg.
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Old Jan 09, 2009, 06:27 AM
I'm torquing to you!
Mr Kamikaze's Avatar
Wattle Grove NSW Australia
Joined Nov 2006
7,369 Posts
Quote:
Originally Posted by Mr_Cash
Mr. K,

To verify,

1) you used the factory 1000 mah lipo 2s battery?

2) to clarify/confirm a good working cg, ... could you measure your CG, from the leading edge of the wing near the fuselage, to your CG point? And, this seemed a good/optimum cg spot for good flight?


Will it climb vertical? And/or, how long, may it take, to get to about a 1000 feet up (to glide down motor off from there)?

What do you estimate, flight time on one 2s factory battery, in a non-slope area?

Since you added weight to get your cg, any interest in trying a more powerful heavier 3s lipo, that would allow not using the extra lead weight for the cg, to see
a) if the stock motor & esc can handle it without burning up?,
b) if the 3s would allow it to better climb vertical?, and
c) if it keeps its good thermal & flight properties with the 3s?

Thanks.

Late addition: The ST ASW28 manual, page 8 (online) does suggest using the "line" on the bottom of the wing as a reference point.

The part about "adding 5mm to that line forward", the print is so small, I cant make that part out. But as Mr K says, its the line, not the spar, as the starting point to get to the right cg.
1. Yes standard 1000mah 2s battery. I was surprised to see it is only rated at 10c.

2. CG is 43mm from leading edge at fuse. Yes this was very good CG.

Won't climb vertical. Maybe 35-40 degrees which is ok for what it is. I put it on the watt meter and got 10.5amps and 75 watts on a fully charged battery.

I'm guessing as to how long to get to 1000ft as I only ran the motor for a few seconds today as it wasn't needed. But I'd say about 30-40 seconds. As for how long the flight is from there, well that depends on what the air is doing and how well you exploit it. Could be 5 minutes or it could be 5 hours.

No idea on motor run time at this stage. I'll probably run mine for about 6 minutes in total next time then put it on the charger and see what it takes to fully recharge. Then add or subtract time accordingly.

I won't try 3s. Like I say it's only drawing 10 amps so I'm guessing the motor and speedy are rated around those levels. I'm not worried about 25 grams of dead weight as it's so light anyway. Got to keep in mind what it is, a lightweight foamy floater. Maybe if someone else tries 3s and it's ok I'll give it a go. Otherwise if you want something that gets up higher quicker look at a Multiplex Blizzard, but it will cost a lot more, probably at least double with Multiplex running gear and it won't thermal anything like this one.
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Old Jan 09, 2009, 04:09 PM
Nup, I got nothing!.....
evo62's Avatar
Gold Coast, Australia
Joined Jun 2007
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I've run the motor of just over six minutes (for about 8 minutes of total flight -yep, I'm good at gliding!) and the lipo was down to 8.0volts. It was mostly around 3/4 throttle with a few full throttle climbs. In the reasonably light winds I flew at, it climbs fairly well, I got up to maybe around 60m's and that took a few seconds - guessing at 10? It wasn't a straight line, but one or two ascending circles around me.

Reset my CoG. In my haste I just glanced at the Chinglish instructions - saw them mention measure from the line so assumed they meant the spar. Oh well, it is EPO!

Clovus
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Old Jan 09, 2009, 08:05 PM
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200w, 25A bec, 9x4.7 prop, $20 + ship

If one wanted to upgrade power later, would this fit in the ST ASW28, and be similar weight or not add too much weight, to allow it go vertical, but still give good flight and thermaling?

The nice thing about the ST ASW28, is it is very light for long thermals and glide flights, but still with a huge 79" wing. If there was a motor combo, to get it to 1100 feet up or so, in ten seconds or so, then cut the motor off, ... it would look impressive going up fast, but give very long total flight times per battery with long motor off glides from 1100 feet.

This combo, works with 2s or 3s lipo batteries. So, it can use the stock ST Asw28 batteries, but also could handle a more powerful $15 - $20 3s 1300 mah to 1500 mah lipo. But the 3s lip batteries, weight quite a bit more than the 2s. Would that adversely affect good motor off glide flight and thermaling?

Other $15 - $20 brushless & bec combo's page

May this work?

One problem may be, this is an outrunner motor, where the ST asw28 uses an inrunner?

Another problem, since the motor is up front, the quality of the shaft in the $20 200w motor may not be strong enough to withstand hard crashes or landings on the nose.

Brett measured the stock wattage at 75 on the asw28. The plane weighs 18 oz. That would be 4.1 watts per oz.

The ST asw28 is a light 18 oz.

With the $20, more than 2x more powerful 200 watt motor and bigger 25a bec, and lets say, it adds 2 oz of motor weight (?) to the plane, it would now have 10 watts of power per oz, instead of only 4 watts per oz on the stock asw 78.

The latter, would be the equivalent pwer to weight ratio, of a 400 watt motor, in a 40 oz plane?

The wings may have to be taped, to increase strength, to prevent breakage under the power doubling?

Any electrical experts out there, that could comment if this is viable? And if the good light stock asw28 thermal glide flight would still be there, with a possibly heavier 200 watt motor and 3s 1300 mah lipo?

This 200 watt upgrade would not have to be done immediately, but an option maybe later, after the stock motor is well used and/or worn out.


**********

Appendix:

Weight comparisons.

The 200 watt above motor, weighs 65 grams, the bec 25 grams, for a total 90 grams.

Anyone have weights, for the stock asw 28 motor and esc?

As I recall, the 3s 1300 batteries weigh about 99 grams, versus the stock asw28 2s at 57 grams, or 42 grams more.

The entire flying weight of the st asw28 with motor, battery, etc., is only 550 grams, as I recall.


****************

Another alternative, is to simply get a more powerful 25a esc (?), for the stock motor. Then get a longer lasting, more voltage power, 11.1v 3s 1300 mah lipo. If the stock motor can handle it (?), that by itself may give a boost to the plane climb power, while benefiting from not having to add the weight of a heavier motor.

*******************

Brett,

the 43 mm cg from the front edge, given a 155mm root chord, gives a 27.7% cg. That's in the low end of the range I have seen recommended generally, of 25% to 35%.

32.5% works well on my 55" wild hawk plane.

This means, it might be interesting, to take out the 25 grams of lead weight you added, and re-measure your CG from the front edge.

A 32.5% cg would be about 50 mm.
A 35% cg would be about 54 mm.

If its 54 mm or less, ... say, at 50 mm, ... I would be tempted to try to fly it to see how it does with the less weight.

Or, just change the cg by the 3mm variation allowed by the asw28 manual, ... i.e., take out only enough weight, to give a 46mm cg, instead of your present spec 43mm cg. Test fly it, and if flight improves, you can take out some more weight, and, move the cg to 49 mm, and re-test fly. Repeat until the optimum is found. ... If no improvement at 46mm, then, you know there's no need to even try 50mm or above.

If it flys good without the extra 25 grams of weight, and the CG is still in that 30% to 32% to 35% general recommended range, I would think it would thermal better (lighter) and glide longer (lighter) without the extra weight.

If you try it, let us know the results.

Of course, be ready to bring it back down fast if it doesn't seem to fly right, to avoid a possible crash or hard landing.


**************

Steve,

I could not wait any longer to try out the stabilizer down revision. I test flew my 55" plane while it was snowing today. I changed the stabilizer to "much less down in front" as we discussed. I also accordingly re-adjusted the battery position back a bit, and raised the elevator a bit, to flat from very slightly down.

It seemed to fly very smooth, improved, more stable. I'm looking forward to confirm a good repeat flight, this weekend when the snow stops, maybe Sunday. Thanks.
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Old Jan 10, 2009, 12:11 AM
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ST DG 1000 similar,
the 100% scale 18 m “Turbo” LS8-sT made by DG.

Retractable 2 cyl. 2 stroke engine, 17 liter tank, 10 produced.
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Old Jan 10, 2009, 02:09 AM
Nup, I got nothing!.....
evo62's Avatar
Gold Coast, Australia
Joined Jun 2007
2,174 Posts
Pretty windy here - the 'net says 20-22knots, but after watching Mr K's vid I figured it could fly in a bit of wind. I flew a bit further inland and the wind felt around 15-18 knots (I'm a old sailor). I put the battery all the way forwards and put 10grams of extra weight in. CoG was a smidgeon forwards of 5mm.

I had 3 throws and each was pretty good, the first I kept it low and did 1 circuit before landing. Each throw I got a bit more adventurous and the last one I put it up a bit higher and did a few circuits. I was flying in a flat paddock and downwind it really got moving. I did need the motor on to fly back upwind of me but landing was a cinch, twice I was able to drop it almost at my feet.

I never thought I could fly in this much wind without going to a big Gasser. Stoked!

Clovus
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Old Jan 10, 2009, 02:11 AM
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Maiden Video Questions:

Steve,
Brett,

This is a really nice mesmerizing video.

Someone said in the beginning of the video, "Its not the fin, its the wings not square". What does that mean?

Do the wings seem to be very snug in the fuselage, with no worry, they will come out in flight? Would an owner need to glue them in, or? Do the wings disassemble for travel, and reassemble snug for flight, well?

At the end of the video, the plane disappeared beyond the grass (into the ocean?). Where did it go, and was that planned?

Thanks.


***************


Brett,
Clovus,

Have you seen or read about the new 78" 3ch 3s lipo 27oz Parkzone Radian ?

After flying the new scale 79" 4ch 2s lipo 18oz ST ASW28,

a) how would you compare the two planes,
b) which do you like better, and
c) why?
d) after multiple st asw28 flights and optimizing the CoG, where now seems to be its best CoG point?

Thanks.
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Old Jan 10, 2009, 04:17 AM
Nup, I got nothing!.....
evo62's Avatar
Gold Coast, Australia
Joined Jun 2007
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Cashie,

The wings come apart for transport, although they fit in my Honda Jazz assembled. There is a screw about 3/4 along the wing that tightens against the spar. I find they need to be really tight, or the wings work their way loose too easily.

Yeah,

I heard about the Parkzone Radian, everything I read is good, but it's almost $400 pnp so I decided to go the ASW28. I wondered after my maiden if I shoulda got the Radian but after changing to my JR Trans, moving to the right CoG and adjusting the control surface throws I'm getting into the groove.

Clovus
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Old Jan 10, 2009, 04:24 AM
Nup, I got nothing!.....
evo62's Avatar
Gold Coast, Australia
Joined Jun 2007
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Forgot the mention I flew for a total of 8minutes 40seconds (throttle only for launch, going upwind and bringing it in to land) and the lipo was at 8.18v when I put it back on the charger. I guess that means that 20-30 minutes would not be unreasonable.

Clovus
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Old Jan 10, 2009, 06:09 AM
I'm torquing to you!
Mr Kamikaze's Avatar
Wattle Grove NSW Australia
Joined Nov 2006
7,369 Posts
Quote:
Originally Posted by Mr_Cash
Maiden Video Questions:

Steve,
Brett,

This is a really nice mesmerizing video.

Someone said in the beginning of the video, "Its not the fin, its the wings not square". What does that mean?

Do the wings seem to be very snug in the fuselage, with no worry, they will come out in flight? Would an owner need to glue them in, or? Do the wings disassemble for travel, and reassemble snug for flight, well?

At the end of the video, the plane disappeared beyond the grass (into the ocean?). Where did it go, and was that planned?

Thanks.


***************


Brett,
Clovus,

Have you seen or read about the new 78" 3ch 3s lipo 27oz Parkzone Radian ?

After flying the new scale 79" 4ch 2s lipo 18oz ST ASW28,

a) how would you compare the two planes,
b) which do you like better, and
c) why?
d) after multiple st asw28 flights and optimizing the CoG, where now seems to be its best CoG point?

Thanks.
If you look at my tailplane it is not parallel to the wings. I didn't bother to do anything about it because it flew fine.

The landing was fine it's a big grass slope.

I didn't buy a Radian because a) it's elevator rudder only and b) I really don't like the look of it
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Old Jan 10, 2009, 04:10 PM
Nup, I got nothing!.....
evo62's Avatar
Gold Coast, Australia
Joined Jun 2007
2,174 Posts
Quote:
Originally Posted by Mr Kamikaze
If you look at my tailplane it is not parallel to the wings. I didn't bother to do anything about it because it flew fine.
I noticed the tailplane is really wobbly and the top of the T (elevator) moves around easily, even when screwed on tight. I thought it might be due to the thin EPO foam Stabiliser. I was wondering about putting a bit of carbon rod in there to stiffen it up, but thought I'd see how I go first.

I guess the flex makes it a bit more forgiving...
Clovus
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Old Jan 10, 2009, 06:50 PM
I'm torquing to you!
Mr Kamikaze's Avatar
Wattle Grove NSW Australia
Joined Nov 2006
7,369 Posts
Just got back from some flatland action. Had 10-12 motor runs of about 30-40secs for a total of 6 minutes total run time on the motor. With some very light thermal conditions this gave a total flight time of between 25 and 30 minutes. There was another homebuilt eglider up which thermals really well and the ASW28 thermalled just about as good as it. I'll post back here later when I've charged the battery back up so I can let you know what it used in that 6 minutes.
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