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Old Mar 25, 2012, 06:42 PM
Tony Audsley Retired Locksmith
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For anyone interested, I have now finished my version of the Seawind made from Depron.

Here is the link: http://www.rcgroups.com/forums/showt...5#post21131539

Lockey
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Old Mar 26, 2012, 07:49 AM
We shall serve the Lord
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CRC makes some fine products, but CorrosionX is the only product I've found that will actually prevent rust from starting on water-logged pushrods.
McD
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Old Apr 12, 2012, 04:49 PM
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First flights

I have been able to get my Seawind out for its first few flights. I went right for the water instead of ROG. No surprises with its handling, I learned a lot about assembly and flying tips from this thread. I have one concern which has been discussed many times regarding the thrust line of the pod mounted motor. I have added a washer to the top motor mount screw to add a slight up angle to the prop. It pitches down slightly upon adding power but not too bad. My impression however is it flies like it is opposing itself between the high thrust line and the lift of the wing as evident of the pitch up when when throttling back to idle in flight. It glides great! So is this as good as it gets or do I need more upthrust?
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Old Apr 12, 2012, 05:26 PM
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I think you went the wrong way with your thrust adjustment. The more "Up" thrust up put on the motor, the more "Up" elevator trim will be required for level powered flight. When you reduce throttle, the plane will tend to zoom up because of the "Up" elevator trim. You need to put in some Down thrust in the motor which will require more down trim for level powered flight and that should reduce the climbing when you reduce power. You will still have a tendency to nose down when you power up quickly due to the high pylon mounting location of the motor.

Remember, the motor is mounted BEHIND and above the CG of the plane. Motor thrust adjustments are just backwards to normal front motor planes.

McD
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Old Apr 12, 2012, 05:43 PM
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Originally Posted by kingsflyer View Post
I think you went the wrong way with your thrust adjustment. The more "Up" thrust up put on the motor, the more "Up" elevator trim will be required for level powered flight. When you reduce throttle, the plane will tend to zoom up because of the "Up" elevator trim. You need to put in some Down thrust in the motor which will require more down trim for level powered flight and that should reduce the climbing when you reduce power. You will still have a tendency to nose down when you power up quickly due to the high pylon mounting location of the motor.

Remember, the motor is mounted BEHIND and above the CG of the plane. Motor thrust adjustments are just backwards to normal front motor planes.

McD
+1 McD hit the nail on the head.
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Old Apr 12, 2012, 08:47 PM
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As was probably mentioned in an earlier post, it may just need some up-pitch for takeoff. I haven't flown mine since my boat came out of the water last fall, but I believe I give it about 10 clicks of up-trim on my radio, give full throttle, and it's in the air in no time. I bleed off the up-trim once airborne. A nice flying plane once trimmed properly.
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Old Apr 13, 2012, 04:54 PM
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Originally Posted by kingsflyer View Post
I think you went the wrong way with your thrust adjustment. The more "Up" thrust up put on the motor, the more "Up" elevator trim will be required for level powered flight. When you reduce throttle, the plane will tend to zoom up because of the "Up" elevator trim. You need to put in some Down thrust in the motor which will require more down trim for level powered flight and that should reduce the climbing when you reduce power. You will still have a tendency to nose down when you power up quickly due to the high pylon mounting location of the motor.

Remember, the motor is mounted BEHIND and above the CG of the plane. Motor thrust adjustments are just backwards to normal front motor planes.

McD
Not so fast...the motor is only faintly behind the CG of the model and upthrust reduces the amount of up trim needed for flight...it does not increase it. It also reduces the abrupt pitch down effect of adding lots of throttle at low speed, which improves takeoffs, approaches and landings. My Seawind showed noticable improvement in flight behavior with large power changes with the extra upthrust added.
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Old Apr 13, 2012, 04:55 PM
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Originally Posted by stvclif1 View Post
I have been able to get my Seawind out for its first few flights. I went right for the water instead of ROG. No surprises with its handling, I learned a lot about assembly and flying tips from this thread. I have one concern which has been discussed many times regarding the thrust line of the pod mounted motor. I have added a washer to the top motor mount screw to add a slight up angle to the prop. It pitches down slightly upon adding power but not too bad. My impression however is it flies like it is opposing itself between the high thrust line and the lift of the wing as evident of the pitch up when when throttling back to idle in flight. It glides great! So is this as good as it gets or do I need more upthrust?
Adding a washer to the TOP motor mount screw actually pitches the motor/prop angle down, not up. My model does better with a little bit of extra upthrust (washers under the the lower motor mount screws.)
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Old Apr 13, 2012, 08:52 PM
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Thanks everyone for the good insight. I thought I might try to clarify to make sure we're on the same page.
By upthrust, I have the center line of the motor and prop angled slightly up from the factory thrust line.
Also to clarify, I have the washer on the top screw since my motor is mounted from behind the firewall. In other words, the screw goes thru the front of the firewall, thru the washer then the motor, thus providing a couple of degrees of angle above factory. Thanks again for the input.
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Old Apr 13, 2012, 11:11 PM
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Originally Posted by stvclif1 View Post
Thanks everyone for the good insight. I thought I might try to clarify to make sure we're on the same page.
By upthrust, I have the center line of the motor and prop angled slightly up from the factory thrust line.
Also to clarify, I have the washer on the top screw since my motor is mounted from behind the firewall. In other words, the screw goes thru the front of the firewall, thru the washer then the motor, thus providing a couple of degrees of angle above factory. Thanks again for the input.
That makes more sense. I forgeot about the stock motor mounting through the firewall. I went to a different mount in mine so that the motor is in front of the firewall, not in back. I added a washer to each bottom screw of my 4 screw motor mount. The shorter wood motor mount holds up better than the long fragiel stock motor mount.

One way to proof the thrustline is to do a flyby at about 40% power, straight and level. Rapidly increase the throttle to full and see how much the model wants to pitch down.

The slight addition of upthrust may also contribute to a slight upper surface blowing of the horizontal tail and elevator,which also works to reduce nose down pitching under power.
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Old Apr 26, 2012, 05:17 PM
Fixed and rotary wing flyer
United States, CA, Newark
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Ready to jump into a seawind

Im about ready to click the checkout button on a Seawind ARF from Amazon for $109 shipped and am planning to buy the rest of the parts needed from hobbyking to stay in a reasonable budget.

All I have are 2200 3s 25c lipo's I use on my 450 heli, and I really want to avoid buying batteries. Would the Turnigy 2830-1000Kv motor be a good choice? It's the closest I could find to the recommended rimfire for less than 1/2 the price (it's in my shopping cart discounted at $13.49). Or would the Firepower 400 be a better choice. What prop size would I use for either motor?

For the ESC, would the Hobbyking 30A ESC with 3A UBEC be ok?

I'm also planning to use 3 HXT900/SG90servos. Any thoughts on those?

I've had my eye on this little plane for over a month now, and am about 1/4th the way through this thread, but can't wait any longer

Thanks!
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Old Apr 26, 2012, 06:13 PM
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Originally Posted by fabric8 View Post
Im about ready to click the checkout button on a Seawind ARF from Amazon for $109 shipped and am planning to buy the rest of the parts needed from hobbyking to stay in a reasonable budget.

All I have are 2200 3s 25c lipo's I use on my 450 heli, and I really want to avoid buying batteries. Would the Turnigy 2830-1000Kv motor be a good choice? It's the closest I could find to the recommended rimfire for less than 1/2 the price (it's in my shopping cart discounted at $13.49). Or would the Firepower 400 be a better choice. What prop size would I use for either motor?

For the ESC, would the Hobbyking 30A ESC with 3A UBEC be ok?

I'm also planning to use 3 HXT900/SG90servos. Any thoughts on those?

I've had my eye on this little plane for over a month now, and am about 1/4th the way through this thread, but can't wait any longer

Thanks!
The batteries are probably around 200 gms or more, right? The Firepower motor you have picked out is pretty light, < 2 oz. With those batteries you can afford a slightly more powerful motor and a bit more weight.

I have an ST.10, rated at 1200kv, on my Seawind EP. Its rated at 320 watts but is good for 220 or so for continuous operation. With a 185 gm. battery I still need a bit of weight on the tail to get the CG back to the spar, which is substantially behind the recommended CG of 1" behind the leading edge. The ST .10 is replacing a 1400 kv, BP hobbies 180 watt motor that I burned up one bright summer day (leaves a nice smoke trail). I'm flying at altitude, Tahoe, but I would still recommend a >200 watt motor with at least 1200kv. I have flown almost 15 minutes using a zippy 1600, so your 2200's will get you plenty of time in the air but you need a bit more pep to compensate for the battery weight.
Your esc should be fine; you're prop diameter limited with the SWEP so you'll be hard pressed to get more than 20 amps into the motor unless you go to a very high kv setup.

The servos sound fine, but you'll need to open up the precut openings because the Futaba servos they recommend are very small.

Make sure you treat the esc and the receiver with corrosionX because no matter how well you bag things they still get wet.
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Old Apr 26, 2012, 07:54 PM
Fixed and rotary wing flyer
United States, CA, Newark
Joined Sep 2011
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Thanks, Bob. I just saw that a while back, you suggested to someone a Tower Pro 2409-12t which from the looks of it, is just what I need. But unfortunately, they're out of stock. Can you suggest another motor with about the same specs and price? Or should I just hold out and wait?

Would theTurnigy 2210-1400 be a good alternative? How about the GF 2215/15?

My only worry with these motors would be I'd have to hack away at the motor mount (like cut about the front half off) since this looks like they have to be mounted in front of it. Should I avoid these bell-type outrunners? This electric stuff is so confusing compared to my nitro days. I've been trying to understand the motor number references (ie 2830 means 28mm diameter by 30mm length) and just when I think it starts to make sense, some other manufacturer identifies their motors using some other format.
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Last edited by fabric8; Apr 26, 2012 at 08:36 PM. Reason: Added motor options
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Old Apr 26, 2012, 11:01 PM
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Before we go much further, I hope you realize that the Seawind has a unique, 3 hole mounting scheme that "front mounts" the motor. The motor mounts inside of a plywood cage. Many of us have just cut off the cage and just glued the appropriate amount of balsa and plywood to get the prop mounted the appropriate distance in front of the cowl. You might want to go the the Great Plains (or Tower hobbies) website to see if the motor mounting of the Seawind is shown in the manual. I'd look it up, but my manual disappeared.

That said, the Turnigy 2210-1400 is a real deal for the money. I have used it up to about 25 amps on a Polaris XL. The Seawind is a bit lighter than the XL with a lot less drag, so the 2210 should work very well with an EMP 8x5 prop or with an APC 8x6 if you don't use full throttle all of the time. But to make things look nice you will need to cut off the extra long shaft a buy a 3mm collect adapter to hold the prop.

Your alternative motor, the GF 2215/15 looks very interesting. Not only does it have more power, but it looks like it has a 3 hole mount which might fit the existing mount on the Seawind (no cutting of the plywood cage). To make that happen, enough of the shaft needs to extend from the stationary end to allow you attach a collect adapter. Or you might be able to push enough of the shaft through the motor to allow that to happen. You might want to contact the vendor to see if that is possible. Also, you need to be able to solder to use that motor-- the motor describtion says that the connectors are not installed.

Good luck.

By the way, one quirk of the Seawind is that it dives if full power is applied quickly. It's hard to Throttle up for a go around near the ground.
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Old Apr 27, 2012, 01:12 AM
Fixed and rotary wing flyer
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Yeah, I realize the 3-hole mount that the SWEP has. I've been referencing this article for some time now and have carefully studied the motor mount shown in the assembly pics.

I built (and repaired) a bunch of Goldberg kits when I used to fly in the 90's and am comfortable with balsa and ply, but this will be my 1st foam plane. I'm guessing epoxy should be used for any new plywood mount I end up fabricating? BTW, would you happen to have any pics showing your modified mount? I'd appreciate some ideas.

I'll check with the vendor tomorrow on whether the shaft of the GF2215/15 can extend far enough through the other side to use a collet adapter. I can solder, so that's not a show stopper for me. If it doesn't work out, I'll just order the 2210-1400 from hobbyking. I really appreciate all your help!
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