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Sea Angel: First Powered plane in 15 years for me!

#1
Hi folks. I recently got back into RC after a long break. Lots has changed! I'm blown away by the power and light weight of the new motors and batteries. It used to be a challenge just to keep an electric plane light enough to mush around for 4 minutes.

I used to be more of a slope soarer guy, but I'm digging the power and affordability of the modern electric stuff (also don't live near a good slope anymore). I also dig this cheap/fast foam board style as a lower stress/fun way to just try stuff.

So I maidened my Sea Angel today! It was almost disastrous, but old reflexes kicked in and I brought it down safe. Wind gusts up to 20 mph were happening, and I set my aileron throws way too high, whooo! Late in the evening I flew again with much calmer winds and it was much more relaxing.

I do have a question in here. The CG per the dots on the wings seems pretty conservatively forward, and it did seem to fly very stable in the pitch direction, and didn't mind tons of elevator throw. My gut feeling is that the CG could stand to move back a bit, and it would make it a bit more lively in pitch, and maybe even reduce the amount of down trim needed at high throttle. Has anyone played with the CG on this bird?

Thanks for any ideas,

Dan
 

mach1 rc

Well-known member
#2
I just printed the plans for the sea angel so I'll probably be working on that in the next few days. I have noticed that the cg on some planes is to far forward. I'd say just go ahead and adjust the battery back.
 

SP0NZ

FT CAD Gremlin
Staff member
Moderator
Mentor
#5
FT is oriented towards learners so they tend to have a forward leaning CG with a low CofP wing.

I also used to fly slope, but Reno is full of hills facing the wrong way.
Just to reiterate what @Piotrsko said, the CG that you get with the kits and plans is always conservative and geared toward a forgiving first few flights for beginners. Play with the CG until you find the sweet spot for your flying style. If you find something that works really well for you, please share it so others may benefit. We put the "TEST" in Flite Test. :cool:
 

BATTLEAXE

Well-known member
#6
Hi folks. I recently got back into RC after a long break. Lots has changed! I'm blown away by the power and light weight of the new motors and batteries. It used to be a challenge just to keep an electric plane light enough to mush around for 4 minutes.

I used to be more of a slope soarer guy, but I'm digging the power and affordability of the modern electric stuff (also don't live near a good slope anymore). I also dig this cheap/fast foam board style as a lower stress/fun way to just try stuff.

So I maidened my Sea Angel today! It was almost disastrous, but old reflexes kicked in and I brought it down safe. Wind gusts up to 20 mph were happening, and I set my aileron throws way too high, whooo! Late in the evening I flew again with much calmer winds and it was much more relaxing.

I do have a question in here. The CG per the dots on the wings seems pretty conservatively forward, and it did seem to fly very stable in the pitch direction, and didn't mind tons of elevator throw. My gut feeling is that the CG could stand to move back a bit, and it would make it a bit more lively in pitch, and maybe even reduce the amount of down trim needed at high throttle. Has anyone played with the CG on this bird?

Thanks for any ideas,

Dan
Hey buddy and welcome to the forums and the Flite Test family. I have never built the Sea Angel specifically but there have been over 20 others to cross my bench. I will say you are not wrong about the CG, they do tend to be a little to forward for a more experienced pilot, and for you it must be like riding a bike, a flight or two and your the master of the sticks. As you probably know you have some leeway, anywhere from 1/4- 1/3rd of the wing chord, measured from the leading edge will be fine. Usually 1/3rd is the better place to work with, this also depends on what kind of flying you do.

Congrats on the maiden BTW, brought her home in one piece (y)
 

Merv

Well-known member
#9
The CG per the dots on the wings seems pretty conservatively forward,
I agree with @SP0NZ, start with the stock CG, get the plane trimmed out. Then move the CG to suite your flying stile.

For the FT planes that I have calculated the CG for, they all are at 25%. Thats where I start when I maiden a new build, when the plane is trimmed out, I move the CG aft to about 30%. I find a bit of instability adds to the fun.

However, when I was at Flite Fest 19, I shared the table with three noobs. They all built Tiny Trainer from a kit. When it was time, I was given the honor to maiden their planes. All 3 planes were balanced at the mark on the wing. All 3 were tail heavy, they were flying squirrels. All 3 flew great when the CG was moved forward 1/4 inch. I’m not sure if there was an error in construction or if the CG on the kit was off.
 
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BATTLEAXE

Well-known member
#10
I agree with @SP0NZ, start with the stock CG, get the plane trimmed out. Then move the CG to suite your flying stile.

For the FT plane I have calculated the CG for, they all are at 25%. Thats where I start when I maiden a new build, when the plane is trimmed out, I move the CG aft to about 30%. I find a bit of instability adds to the fun.

However, when I was at Flite Fest 19, I shared the table with three noobs. They all built Tiny Trainer from a kit. When it was time, I was given the honor to maiden their planes. All 3 planes were balanced at the mark on the wing. All 3 were tail heavy, they were flying squirrels. All 3 flew great when the CG was moved forward 1/4 inch. I’m not sure if there was an error in construction or if the CG on the kit was off.
Huh, really... maybe that's the issue I had with my 2 attempts at the TT
 
#11
Good info.

Battleaxe, I posted in another thread, but the motor started making a horrible noise on the third flight, and I lost most of my power. I landed and it seems the bell is loose, and makes bad grinding sounds when I play with it, and it also seems able to move forward, with force. I can't get to the backside of it because of the design of the pod on this plane... I have an email in with FT to see what might be going on.
 

BATTLEAXE

Well-known member
#12
Sounds like the snap ring came loose, you will have to remove it from the power pod to check but if it is still rattling around in there rubbing on essential parts you could be doing more damage. The bell will be able to move forward and back if this snap ring is removed, the magnets will hold it in place but I guarantee that's what it is.
 
#13
Thanks for the info. I didn't look too close at the motor construction before I installed it. Is this something that I could fix if I took the motor out, or is it a very specialized part (that most likely flew off into the field somewhere) that I'd need to find or fabricate?

Also, why would it come off?

Thanks again for the tips.
 

BATTLEAXE

Well-known member
#14
You could fix it yourself really easily. It is a tiny snap ring though, you might even have extras in your kit it came in. Just a small "C" shaped open ended ring, snaps into a groove in the motor shaft. Holds the whole works together.
 

speedbirdted

Well-known member
#17
I built one of these with a lot of modifications for ease of working on and durability a while ago (most notably changed the pushrods out for housed Bowden cables and made the wing, motor and float struts out of 1/8 ply instead of foam) plus covered the whole thing in Monokote so it would keep water out much nicer, and it was such a tank that it got pretty frequent flights, including absorbing some minor crashes, up until I made the decision to retire it last weekend. I find that it actually flew the best with the CG slightly aft of where it's specified - 30-35% seems to work the best, and I suspect the slight sweep is to blame for this (though mine ended up having a little more sweep than is standard so I would be conservative on this number) This also moves the CG closer to the step which makes water takeoffs easier in my opinion. I still did need some nose weight though as my elevator and rudder setup involved 3 servos in the back instead of the normal two plus the additional weight of the cable housings which were aluminum tubing.
 
#18
Cool, well I'm looking forward to flying it again with the CG back just a bit further.

As far as durability and water resistance, I was considering brushing a coat of marine epoxy that I have on the bottom and bottom sides, instead of using wimpy hot glue like they recommend. I haven't tested it yet, but I'd think it would stick just fine to the foam board.

BTW has anyone tried knife-edge with this plane? I briefly tried it before my motor issues and was surprised how well it flew that way. I am thinking all that extra side area from the big motor pod helps. Probably the same reason that the wind seems to toss it around pretty good!
 

speedbirdted

Well-known member
#19
I don't remember ever trying that with mine, though I do remember the high wing and even higher thrust line made it exceptionally poor at advanced aerobatics (though it did Lomcevak very well as that's exactly what a high thrustline is good for)
 
#20
What aerobatics did you find hard to do with it? So far it seems pretty nimble, but then again all my control throws are pretty high. You are probably referring to some stuff I don't know how to do. I did try a Lomcevak years ago with my .40 sized ugly stick but could never get it to happen, haha.