Norms flying Boat

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Himat

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Well, no. For flying boats the step is located just aft of the CG. Roughly the same location as the main gear on a nosewheeler and for the same reasons - it has to rotate in order to take off. Buoyancy determines where the waterline will be and is controlled by the width (beam), not the step location.
If step placement on flying boats are to be discussed, so to be in another thread.
Let’s say there are pros and cons with placing the step of a flying boat hull close to the centre of gravity.
To have the hull step just aft of the centre of gravity is commonplace, but no requirement for a working flying boat hull.

Also keep in mind that as a flying boat starts to move it begins to weigh less, unlike an actual boat.
True and important in seaplane hull design.
 

Himat

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The above photo's show a change . I did not need this to fly I needed to repair damage to the glass at the the point where the wall meets the bottom launch rash had broken through here allowing water to infiltrate I had perceived it to be structural compromise as well I will repaint if its final. This actualy may work against me that amount of V hull could have been providing me with additional hull elevations needed to provide me the rotation. It could also have been just a drag point now removed allowing for a smoothing of the wake reducing turbulence to the aft hulls.
If modification does not work, consider adding a fixed “ski” like extension recouping some of the lost “height” where the bottom of the V was. Maybe four to six inches wide, guesstemating.
 

Norm Langlois

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This is an early walk around video. One of you implied the wish to see some archival photos. This was long ago and was nothing like the end result but still shows some fine construction views. The V tail never flew , but I did have on the water for tests. It scared the hell out of me. It had adverse yaw and no ability to counter it. Enjoy
 
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Norm Langlois

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A few more early pictures of the hullhulljig1 025.jpghulljig1 029.jpg The styrene was formed over a plywood frame. removed and the inner diaphragms installed all surfaces were glassed over . later the modifications were to extreme to explain in just a few pictures over time most of the boat look disappeared as is shown here. on the bottom view there is an extreme forward hump. This was the most hindering part to flight . it caused a bow down drag. I had difficulty visioning what the bow transition to bottom shape should have been . Partly because of the difference of opinion being expressed to me by others. Some said I needed a cutting hull .I always thought I needed a planning hull much like a simple old plywood hydroplane.I was right! the flatter the transition here one can make it the better.

By the way if you want to create with styrene use epoxy resins,very expensive $500 for 5 gallons if you can use urethane foam board you may use polyester $200 for 5 gallons. On the better side of the choice while the urethane forms better it is week and flimsy. the high density styrene is the same weight and much stronger when glassed over. Both weigh aprox. 2# per cubic FT
Regards Norm
 

Norm Langlois

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I would like to see more replies from all of you. If you feel something is to risky say so. In the beginning I was a skeptic. It took some proof about how much a difference skinning both sides of a foam panel could be used to make a hull. I took a long look at the basic components of my plan to build . I consider the hull low risk area. therefore damage acceptable. with repair a maintenance , as gas is to fly. for my plane to be an UL i took this as par for the course. I put the real safety margin into the airframe.I limited to very little welding and great care to the engineering of junctions and there load baring to the adjacent materials. so in the attachment to the hull is one of my concerned area. the material used is windshield adhesive. the latest urethane type. the concern here is not that but the actual bond between the resin and foam.I will probably make a through bolt fuselage all the way to the bottom of the hull . I have never been comfortable about that connection.

Speak your peace let me know what your thinking about all that which UL builder methods concern you. It does take risk decisions to make an Ultra light plane. I tried to minimize mine. I have had a couple hard water landings without any damage.I take those as proof I did partly something right.
 

bmcj

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I would like to see more replies from all of you. If you feel something is to risky say so. In the beginning I was a skeptic. It took some proof about how much a difference skinning both sides of a foam panel could be used to make a hull. I took a long look at the basic components of my plan to build . I consider the hull low risk area. therefore damage acceptable. with repair a maintenance , as gas is to fly. for my plane to be an UL i took this as par for the course. I put the real safety margin into the airframe.I limited to very little welding and great care to the engineering of junctions and there load baring to the adjacent materials. so in the attachment to the hull is one of my concerned area. the material used is windshield adhesive. the latest urethane type. the concern here is not that but the actual bond between the resin and foam.I will probably make a through bolt fuselage all the way to the bottom of the hull . I have never been comfortable about that connection.

Speak your peace let me know what your thinking about all that which UL builder methods concern you. It does take risk decisions to make an Ultra light plane. I tried to minimize mine. I have had a couple hard water landings without any damage.I take those as proof I did partly something right.
I can't speak to hull design, but I see no problem with your approach, espcially since the flying surfaces and airframe are conventional.
 

Himat

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It took some proof about how much a difference skinning both sides of a foam panel could be used to make a hull. I took a long look at the basic components of my plan to build . I consider the hull low risk area. therefore damage acceptable. with repair a maintenance , as gas is to fly. for my plane to be an UL i took this as par for the course. I put the real safety margin into the airframe.I limited to very little welding and great care to the engineering of junctions and there load baring to the adjacent materials. so in the attachment to the hull is one of my concerned area. the material used is windshield adhesive. the latest urethane type. the concern here is not that but the actual bond between the resin and foam.I will probably make a through bolt fuselage all the way to the bottom of the hull . I have never been comfortable about that connection.
If the design with gluing the hull to the fuselage is sound or not I would think is down to the details.
  • Given enough area, fibreglass distributing and taking up the load it might work ok on an ultralight airplane.
  • If the metal frame is bonded directly to the foam and with little area it is probably no good.
After a close examination someone skilled and experienced in composite design and manufacturing could probably give and educated answer.

Close monitoring of the condition as the plane is used is another possibility to find out.
 

Norm Langlois

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thanks guys for the replies
Himat You mention a ski. I have been thinking about that, it always comes back to a drag any addition would add drag. I would consider a flush hard plate I have heard somewhere there is a design that rides on such a diamond plate or some hing such just before rotation. I can not see how I can add anything back to gain the elevation though.

On the foam works. I do have a fiberglass skin then the adhesive to aluminum. Early on I was not doing my glass work in the best ways. One should definitely. use some sort of perforation before applying resin . I did not do so and the bond to foam is less than optimum. High density styrene has a plastic film cover this was removed but no perforation . Epoxy has proven to be a much more resilient than polyester. I mention a possible option if urethane foam was used, I would not , saving money here is not worth doing. I recently used polyester on a shell for my transport trailer it is poor grade surface ,epoxy is a much harder surface. On
the trailer well the cost is worth the saving there. it will take about 15 gallons before I finish that shell.

If anyone wants to know about using foam to construct objects is there any info here? I had to learn on my own. what to use to even glue foam to foam with and stay light etc.
 

Norm Langlois

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Hi all
I did take the plane out and test fly, the hull mod. I am not pleased at all.Unfortunately it did nothing to help,the take off. As well no improvement to rotation. I will ponder what to put back on to improve the or even just return what I had. The loss of elevation relevant to the rear floats is absolutely not allowed.It seemed to create additional drag while making it extremely difficult to climb up on step. I was only able to get up on step with a colder engine .I am trying to analyze that. there is more power at the beginning of use than after a few flights.If after I go air borne I return to a stop I cannot get out of the hole unless the engine cools . This engine has less than 30 hours on it and is not scored in any way, just maybe not tuned optimal. That is not relevant to the test. optimized or not it proved to be a down turn in performance.
Now it has to be shelved till next year. I made a promise to the wife to keep my attentions to the new house. I will probably make some kind of ski as Himat suggested to regain my elevation and hole shot . Get the plane on step and its not hard to get into the air. I put back another item that hinders rotation but gave better stick pressure I may also need to rethink this as well. this is a reverse curve [elevator trim] trailing edge.
 

hjs

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Norm
Good to hear from you again.
I wonder what "improvements" you made on the hull. To obtain good dynamic lift force must all edges be very sharp and the planing surface perfectly smooth. It is important that the bottom and transom meets in an absolutely sharp edge. To get more dynamic lift can the bottom aft be fitted with a concave curvature, or be equipped with an interceptor. Interceptor depth can be adjustable and thus adapted to the lifting power needed.

More pictures, please.

JS

sassdesign.net
 
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Norm Langlois

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Hjs
Look at the pictures on post #59 They show the before and after. Just the removal of that little bit caused so much undesirable effect . No other changes were made that would have effected the climb to step. that small wedge reduced the elevation and deflection water allowing to be sucked downward instead. Now I need to put back something Just What I do not know I could make it the same and replaceable with ware and tare from launch rash. Or maybe some enhancing shape.

I have to admit I must have just thrown everything in the air. When it came down everything came out just right. I had no idea such little things make it not work at all. I have been tweaking for some time now . There is certainly room to fine tune . But an ULTRA LITE hull must be just that. Smoothing takes more resin and that means more weight. I can use shape but that will not be smooth unless it can be achieved with only 2 layers and no gel coat.
 

msogren

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Jun 28, 2007
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Nice build Norm.
Take a look at the early Buccaneer hull . It i s pretty flat in the nose area ,( most pressure under power).
Also for gluing foam to other stuff and even it self, do some testing with the Gorrilla glue types. They work well. The model guys use a "woodpecker" for prep and some course paper. Paint the glue with latex to seal . It continues to dry out if not painted. I have seena 10yr life span painted and about 2 yr unpainted. It holds my VG to my wing. And much of my plane together.
MM.
 

garrywarber

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That is disturbing. I had been looking at your article in print and thinking on making my Invader amphibian. I believe your design was Invader-inspired?


 

Norm Langlois

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That is disturbing. I had been looking at your article in print and thinking on making my Invader amphibian. I believe your design was Invader-inspired?
I had never seen the Invader. I still have not.

My inspirations are completely My own. That is not to say I have not sought info and appearance. My three point hull is out of necessity and completely generic to my view. modified and finalized by others opinion of improvements for better workings. The base aircraft is a plane called the Poorboy . even though the structure looks nothihg like it. I had realized the poorboy could never be a legal UL seaplane. Not with wheels anyway. I worked on an entirely different design (a flying wing) I went so far as building a model. The behavior on the water led me to believe it would make a poor seaplane design.
It was a stalling point in my desire to have and to build my own UL. I had wasted nearly a year on that idea. After a few months doing nothing I had an idea to build a machine that would allow me to make light weight aluminum ribs those you can see in the plane are only made by me.
I spent another year making a roll forming machine and developed forming dies . there was a flurry of innovations. from there on and finally the basic wing and that mono spar makes it and the plane what it is. lightening holes have always been part of plane building . I took the simple flare a bit deeper coining makes it more structural almost like increasing the thickness of the entire diaphragm. I liked the triangle shape over round because it resists compression better although it gives up more in torque, that is over come with most of the many other bracing components. Ending up much stronger and nearly as light.
 

garrywarber

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The dementia must be kicking in... Sorry about that; I had you confused with Hugo Van der Heide.
Your set-up to build is amazing. You must have a lot of energy!
Not missing that much never seeing an Invader, and I have a barn of parts waiting for me. :)

I had never seen the Invader. I still have not.
 

Norm Langlois

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1brace with rib.JPG3braceinstalled2.JPG03special forming LE.JPG
these pictures show the as built ribs and the oldest that had individual bracing .I did not like the individual and created an integral internal brace a one piece.

you asked what the channel sizes are.
the outside is .540 wide outside with .500 legs using .035 6061 aluminum The inner brace is .460 outside with .550 legs as well the same material. Although I say I have three sizes I never setup the largest width I just didn't need it. I believe it would be .610 with .450 legs. they all use the same coil stock 1.375 wide .035 thick 6061 aluminum . the two channels were intended to fit together one inside the other.

I learned later in the build that the .540 can have the .500 polystyrene inserted as a braceing material with alternative structure it makes a stronger construction so is the way the tail fin and stabilizer.

I was very ambitious , not so much anymore.
 

BBerson

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Those rib channels look very neat.
How did you curve the rib caps without buckling the channel legs?
 
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