SeaShrike?
 

I put floats on a conventional plane. Due to time and weather restrictions I still haven't had a chance to test it. Now I think I want a dedicated float plane. I have a shrike sitting here that I'm pretty bored with. I thought about turning it into a seaplane. The picture give you a pretty good idea what I have in mind. I might also put floats on the wingtips if they're needed. I'm wondering how raising the engine will affect the flight characteristics. If the line of thrust is moved up, would I need to angle the engine up or down to compensate? I figured you guys with mariner-type planes would have some first-hand knowledge. The only other obstacles I have - other than moving the engine - is 1. the aileron servos are on the bottom of the wing. I'll at least need to move them to the top of the wing and maybe to the inside of the fuse. 2. I'll probably have some weight and balance issuses. I don't know if I can move enough stuff forward to compensate for the engine. Well let me know what you think. I'll probably just buy a kit or ARF, but it's just a thought I had "floating" around. One more question, for those of you that have an engine in a pod, is the fuel tank in the pod too? What about the throttle servo?

RE: SeaShrike?
 

Hey, I'm not sure who's this is, but it's a shrike on normal floats.. I'm sure they will reply soon! Looks like moving the engine isn't really required.

RE: SeaShrike?
 

It's not a shrike. I recently e-mailed the owner about the plane and it's a Jerry Smith Outlaw delta on floats, modified with a water rudder.

I see no reason why a Sea Shrike wouldn't work. You would have to be careful of the CG since planes with a pod mounted engine like the Northstar tend to build tail heavy. Adding 2 floats and a little more fin area would be an easier way to go, but a flying boat Shrike would be an excellent project.

RE: SeaShrike?
 

If the shrike survives the next couple weeks, I'll probably do it. I had planned on recovering it this winter anyway, so I'll just make the project a little more complicated.

RE: SeaShrike?
 

I think you are correct about CG issues. I think it would be terribly tail heavy as the engine was designed to be up front. You could counter this by extending the nose and stuffing all the radio equipment as far forward as possible. If you look at water planes similar to your idea, like the Northstar and Arrow, you will notice that they have very long noses.

The Outlaw in the picture belongs to a guy by the name of Evan-RCU. He spends a lot of time in the Speed forum too. He's got a cool pic there of an outlaw that he bashed into a twin as well.

Jeff

RE: SeaShrike?
 

Extending the nose is a great solution. Not only can I get weight farther forward, but that also means that I have more surface to float. I did a search for the Northstar (I wasn't familar with it) and that's exactly what I was looking to build. It's gonna look a little different, but it will have the same setup.

RE: SeaShrike?
 

Hi, Evan here.... The Outlaw on floats is mine as well as a Twin Outlaw and a Northstar and........ I like fast and I like float planes. The Shrike idea sounds absolutely fantastic!!! Yes you'll have to compensate for the rear mount engine weight but I think that by using a .25-.32 size engine and maybe making it a pusher to move the engine mass forward you shouldn't need to add additional weight to the nose other than moving everything like the battery, receiver and servos forward. Using a three bladed prop will help keep the thrust line low. You can have the servo outlets on top of the wing or use torque rods and have everything inside. Tip floats like on a Northstar WILL be needed and you might want to think of rudders and a water rudder. As far as engine thrust you'll need 3-5° of up thrust if the engines facing rearward(pusher) or down if the engine faces forward(a tractor).

RE: SeaShrike?
 

Good tips. I like the idea of using a pusher setup with a three bladed prop. I have a TT .42 on it, what would be a good three bladed prop? The 10X6 two bladed prop that I have on it works well. The shrike I have already has rudders on it, but the servo for them is on the bottom of the plane. I'll have to move that inside too. I can just extend one of the rudders down for a water rudder. Where do you think I should put the engine? I think on the Northstar the prop disc is right above the CG. Is that right? Is that where I should put this? I'm not going to start this project until its too cold to fly, but thanks for the tips. It will make things easier when I do start in on this.

RE: SeaShrike?
 

On the Northstar the prop disk is behind the CG by quite a bit. I would position the engine by the That Looks About Right Method, you are going for the cool factor after all.... As far as prop..... somewhere around 8x6 or 9x6 three blade, I would try 8x6 first......

RE: SeaShrike?
 

I did some tinkering in paint to get an idea of how this will work. The pictures are scale-ish. I took measurement off my shrike so its pretty close. The prop represents a 4" radius. #5 was my origional idea, but I decided to go with a pusher for CG reasons. #2 would probably be the easiest to balance, but its pretty ugly. I think #3 is a pretty good compromise.

RE: SeaShrike?
 

Yep, three looks good to me too, remember that the fueltank will be forward to help with the CG..... I think the cylinder to prop distance will be farther than your pics...

RE: SeaShrike?
 

If you go with a pusher, remember that the fuel lines still connect to the front of the tank and the clunk is in the rear. Otherwise you can't climb with less than half a tank of fuel :-(

RE: SeaShrike?
 

Sounds like the voice of experience there Jim..;)

RE: SeaShrike?
 

also be aware that the selection of pusher props is limited.
this may cause you to rethink the pusher option

RE: SeaShrike?
 

I did a quick search on Tower and found that they didn't have much for 3 bladed pusher props. I may increase the clearance and go with a 2 blade 10X6. Or I might just build a Northstar. I really like the looks of those.

RE: SeaShrike?
 

"Or I might just build a Northstar. I really like the looks of those. "

Northstars are a proven design, and a crowd pleaser. I know of two that had maiden-flight problems: One had the pilot become disoriented so it crashed (it does NOT look like a conventional plane, and it's fast) Use a high contrast color scheme, obviously different top and bottom.

The other had the hull split on a T&G, and took on a lot of water before beaching. Glass or otherwise reinforce the hull.

RE: SeaShrike?
 

"Northstars are a proven design, and a crowd pleaser. I know of two that had maiden-flight problems: One had the pilot become disoriented so it crashed (it does NOT look like a conventional plane, and it's fast) Use a high contrast color scheme, obviously different top and bottom."

And you've seen me fly the piss out of mine..... right Jim???

Northstars are excellent airplanes and very cool but not the same as what you would get building your Sea Shrike. The SS would be a much faster and more manuverable airplane and you would have the only one, right.... Hmm, I might build one then...

RE: SeaShrike?
 

Good point, Evan RCU. I think you should build one too. I'll still have the only one in WI. I think I"ll be alright with the CG issues. I've got the battery at the rearmost part of the plane and three of the servos and the receiver are behind the CG. If I move all the components to the front of the plane I might be able to balance this thing. I'll get some pictures when I start hacking into it.

RE: SeaShrike?
 

Well, I started tearing into the shrike. It looks like it'll be impossible to balance it without extending the nose. With everthing removed and all the radio gear placed as far forward as possible, it is still tail heavy. This is without the engine, which I had planned to put behind the CG. The problem I see is that if I extend the nose far enough forward, I'll have ridiculously long pushrods. I guess it would work, but the longer the linkages are, the more chances there are for something to bind up or to have too much slop in the controls. The other problem I have is that if I use a 10X6 prop, it will put the engine way above the plane. I mocked it up and it doesn't look nearly as cool as I had hoped. I haven't given up yet, but I'm not very encouraged at this point.

RE: SeaShrike?
 

Here's my new design. I was planning on building the pontoon out of foam a fiberglass. This doesn't work well for mounting servos, but it'll be a good place for the battery and reciever. In this design, the engine is only moved back slightly and the battery and reciever mounted at the front should counteract that. I went with the tractor design so I could use a smaller diameter 3-blade prop.