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Anybody flown the Sea Loon?

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Anybody flown the Sea Loon?

Old 03-30-2005, 11:14 AM
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dieFluggeister
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Default Anybody flown the Sea Loon?

In Oct of '87 "Model Aviation" published a plane called "Sea Loon". Its a .15 pod pusher twin boom sea plane. As I live on the water here in Minnesota and the loon is our state bird I thought it was appropriate that I consider it for a future project.

Has anyone ever seen/built/flown one before? The twin boom floats the the drooped airfoil tips look like an interesting bird. It looks like it should be hot in the air yet slow-n-stable with its flaps down. Depending on how it flies I might want to shrink it and stuff a Big Mig in it!

I see plans are a couple bucks off the AMA site but my type A personality wont let me wait 6 weeks to review the schematic and answer some of my own questions. Anybody have any thoughts?
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Old 04-01-2005, 01:58 PM
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dicknadine
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Default RE: Anybody flown the Sea Loon?

you have my attention. will dig out my old copy out of the pile, if not, will send for the pony express copy. salt water is not too much of a problem, providing you flush everything immediatly, electric thats something else. dick
Old 04-01-2005, 02:19 PM
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dieFluggeister
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Default RE: Anybody flown the Sea Loon?

What did you think of it overall? I have scoured the web and havent found anyone who's seen one let alone flown it.
Old 03-02-2009, 10:47 AM
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dieFluggeister
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Default RE: Anybody flown the Sea Loon?

Well after five years with the plans nailed to the wall, I have cut wood. Right now I have the booms completed and nearly completed with the hull. Wing will be next with that starting this weekend.

Overall my impression of the build? Lots of parts and a fairly complicated plan. I have a few years experience building now and find it a challenge in some respects. Particularly, this plan requires some minor bending of balsa around the complex curves of the planing hull and sponsons and that takes a delicate touch. Building the twin booms seems slow as you need to cut, build and shape twice the parts, but they were fun. I would really recommend a fuselage jig here. If you don't already have one, it would be worth the effort to make one before starting.

I have decided to go electric on this one, with the power unit yet to be determined. From looking at the specs, with a .15 this bird is underpowered - and I am not one to overpower my planes. At 2.5 lbs target weight from the designer, I feel it needs a little more whoopies to perform like a sport plane and take off from water. I will target around 300 watts. I am limited by a 7" propellor which limits the efficiency of realizing the power of a motor this size. It makes me think of a couple solutions... Finding a 3-blade electric prop, raising the engine pylon an inch to accomodate a larger prop, or utilizing one of those contra-rotating setups. I have about a week to make a determination and any input is appreciated. I decided to go electric as it offered the benefit of no 'flame outs' in the middle of the lake, and reducing the weight in the pylon thus lowering the CG of the model. I then may be able to reduce the dihedral of the wing tips and give it a more aerobatic performance.

I have made a few changes to Mr. Lennon's plan for my model. First, I am building all the leading edges with balsa sticks and then sanding to shape. Curiously, according to the plan, the sheeting is just formed around the rib tips and there are no stringers forward of the main spar on the wing and no stringers at all for the tail plane and rudders. While getting an accurate leading edge shape will be a challenge with sanding, I feel that I can build a straighter wing using leading edge strips. I also think it might cut down on inevitable damage to the leading edges. The wing also uses a fairly complex (and as it turns out, HEAVY), brass torque rod system for tail surface control. It is made out of many pieces of brass tubing which adds complexity and weight. I have made the tail booms with enough flexible pushrod cable to route all the way to the servos, cutting weight and complexity. The only thing I need to see is if it causes too much friction and servo drag.

This has always been on my 'to build' list and I am excited to finally get one in my hangar!
Old 03-02-2009, 11:14 AM
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Default RE: Anybody flown the Sea Loon?

Very cool, keep us informed and get us some pictures please.
Old 03-08-2009, 05:10 PM
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dieFluggeister
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Default RE: Anybody flown the Sea Loon?

Here are a few pics so far. Surprisingly, one of the most difficult things to complete so far was the hatch! It took me almost as much as the rest of the hull. I ended up tacking the formers in place on the hull and then building it there. The amount of bending and shaping the wood on this model has been considerable, and I'm finding that many of the pieces have to be fit, reshaped, fit, reshaped... But I'm taking my time and trying not to rush things.
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Old 04-13-2009, 05:39 AM
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Default RE: Anybody flown the Sea Loon?

Watching with interest [8D]
Old 04-13-2009, 05:42 AM
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Default RE: Anybody flown the Sea Loon?

I have the article and Lennons book somewhere Ive seen one built.
Old 04-14-2009, 09:03 AM
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dieFluggeister
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Default RE: Anybody flown the Sea Loon?

I have the wing built now (minus the control surfaces). I decided to use flexible pushrod instead of the brass tubing torque rod system as called for in the plans. I know it lightened things up by several ounces and vastly simplified construction. Building has been put on hold the last couple weeks, but I am back at it again.

As I am cutting incredibly small pieces of plywood and balsa, I wonder about the possibility of a build with foam and fiberglass. A layup over foam for both the wing and the fuse would offer a number of advantages for this seaplane. Weight would be a concern though.
Old 09-30-2010, 01:15 PM
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dieFluggeister
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Default RE: Anybody flown the Sea Loon?

After having shelved the project in deference to fishing, camping, and kids, I recently pulled it off the shelf. I relocated the servos to the boom pods and am outfitting it with a BP outrunner 2810-9T, 45 amp ESC, and running a 3 cell lipo. It will turn a APC 8x6" at 10500rpm static and at 350watts 24Amp.

Originally the plans call for an over all weight at 40 oz. So far I am at 35oz with my 2700mah battery.

Booms and wing being glued up now while I outfit the pod with the electronics.

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Old 09-30-2010, 06:42 PM
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Default RE: Anybody flown the Sea Loon?

It's an Andy Lennon design and the aerodynamics are impeccable.  Andy passed away recently.  His planes are fabulous, but complicated. 
Once you have it built you'll have something of which to be proud. 

I would be very tempted to blow it up 50% and put in a .40, just because all that complexity is really hard to build into a .15 size plane. 
Old 10-01-2010, 06:16 AM
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Default RE: Anybody flown the Sea Loon?

Bottom of a pop can to mix epoxy??? Genius

Interesting design,
but sure looks like it would be hard to seal that all up with the electronics all so close to or below the water line
Old 10-01-2010, 08:15 AM
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Default RE: Anybody flown the Sea Loon?

Looks really cool Mike. I'm assuming there's some sort of fuselage?
Old 10-01-2010, 09:12 AM
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Default RE: Anybody flown the Sea Loon?

scroll up ;-)
Old 10-01-2010, 10:01 AM
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Default RE: Anybody flown the Sea Loon?

Duh
Old 10-01-2010, 12:33 PM
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dieFluggeister
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Default RE: Anybody flown the Sea Loon?

Sealing is made fairly easy since the fuselage pod is considered 'permanently' attached to the wing. Yes I will have some nylon bolts so it can be removed, but Lennon designed it so that pushrods in the fuse are attached to bellcranks on the wing. It makes it quite a process to detach the wing from the fuse. In my application I mounted all the servos in the wing, still, I plan on keeping the fuse attached and sealed with silicone. The booms, tail, and wing are all epoxied together as one unit. Sooooo... transporting this plane will be as one unit but it should stay fairly dry. The place for water intrusion will be the batt hatch which I will seal as best I can.

The pop can was the closest thing I had on hand but it worked great. As you can see, my workshop cleaning staff is on vacation.
Old 10-01-2010, 09:45 PM
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Default RE: Anybody flown the Sea Loon?

That looks like a lot of hard work. Looks great too! Be sure to show how you seal the hatch. It should be interesting.
Old 10-04-2010, 08:35 PM
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Default RE: Anybody flown the Sea Loon?

Tonight I completed the major step of connecting all of the control surfaces and actuating them with the servos. It was pretty cool to see the twin rudders work together for the first time.

Things left to do: installing the battery tray and balance, decorating trim, and constructing a fiberglass cowl for the motor pod. Pictures coming once there is 'visible' progress.

With any luck, I'll be done before the water freezes!
Old 10-07-2010, 07:07 PM
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dieFluggeister
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Default RE: Anybody flown the Sea Loon?

99% completed now. Need to do final adjustment on throws, make sure everything is sealed well and she is ready to go tomorrow. I'm pretty excited.
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Old 10-07-2010, 10:24 PM
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Default RE: Anybody flown the Sea Loon?

Man, that looks AWESOME! I really like the scheme. But that's a funny looking Cox engine on there....
Old 10-08-2010, 07:48 AM
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Default RE: Anybody flown the Sea Loon?

Great thread![sm=thumbs_up.gif]

The flaps and droops make it a STOL airplane.

Introducing the designer:

https://www.modelaircraft.org/files/Lennon-Andy.pdf
Old 10-08-2010, 12:45 PM
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Default RE: Anybody flown the Sea Loon?

Tried some high-speed water taxi tests and found that it DOES need that splash rail around the nose. I thought maybe I could get by without it. Apparently Mr. Lennon did know what he was doing! Oh well back to the shop to construct one...

Otherwise handled well. The twin rudders and their little sub-fins gave it good authority on the water.

Edit - Oh, one more note - since the rudders are not directly in the propwash, at low speeds it turns better when coasting with power off. This is different than what I am used to. Instead of throttling up to make a tight turn, I have to give some juice, then coast. Different technique.
Old 10-08-2010, 06:50 PM
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Default RE: Anybody flown the Sea Loon?

Alright all you seaplane guys, I would love your input.

The splash rail along the nose helped, but I am still having trouble planing out and water fouling the prop and stealing power.

The plane is slightly under the specified weight and everything is built to plan except since I was using electric power, I went with an 8" prop instead of the specified 7" for glow power, and therefore I raised the pylon (thrust line) 1/2".

When power is applied it seems to plow water and does not rise to plane even with full up elevator. At full power it will splash around the main hull and spray will foul the prop.

All incidences are kept to plan. Do you think I should try a positive couple degrees for the thrust line to compensate for the longer moment arm?
Old 10-08-2010, 07:15 PM
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Default RE: Anybody flown the Sea Loon?

Yep, a little more up-thrust and/or some spray rails.  Won't hurt. 
Nice job on the model BTW. 
Old 10-09-2010, 06:21 AM
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Default RE: Anybody flown the Sea Loon?

Agreed a little thrust angle might help. I'd experiment with widening/lengthening the spray rails,, the Fuse Pod looks very skinny to me

You also may need to finesse that onto step a little, apply the throttle slowly to let it get on step before dropping the hammer

good luck

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