skater_719

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I am wanting to build a scale flying boat from scratch. I've been looking through lots of pics and cant really find anything out of the ordinary. So if you know of any unique single engine flying boats, postem up! It will be powered by a .46 by the way. Or if you maybe have some designs of your own, lets see them.

scale only 4 me

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Do you want planes that have plans available, or just the Scale subjects?

skater_719

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Just subject, of course plans never hurt. I made a rough sketch of an idea that crossed my mind, I'll try and post, but no ripping on me, it took about 5 minutes and Ive never used any CAD stuff.

scale only 4 me

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http://www.flyingboats.ca/FlyingBoats-old/index.html

How many at the lake will have a Russian Flying Boat??
Beriev MBR 2 &/or M17 (+ variants)

skater_719

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I like those, does the bottom one have an open cockpit?

scale only 4 me

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Yeah, Looks like that model had a few variants,, the early models with open cocpits

http://www.flyingboats.ca/FlyingBoat...a-History.html

in this pic you can see the nose gunner
http://www.flyingboats.ca/FlyingBoat...iev-MBR2-b.jpg

Wayne22

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there's always the S-39..lots of character there...

Classic Aero sells plans and short kits...

skater_719

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Well decided to go with the MBR2. From the picture it looks like the 1935 one (top pic) has a tractor prop, but so far all I have seen is a pusher. I'm debating the scale I should make it. Normally I just kind of eyeball what I think an engine would be able to pull around, but with that beefy fuse and it needing to plow through the water, its hard to decide. 1/12 scale would be about about a 60" wingspan, which is around the size I like, and I am not looking for any vertical or anything, just scale flying. So all you more experienced guys, using a tt pro 46, what size would you recommend. For the stabs, I cant find any info on sizes, do most of you scale builders just eyeball it, or is there a more accurate way? Last question, I was just wondering, with a prop that high above the plane, wouldn't there be a tendency to nose down under power and what kind of thrust angle would be used to correct it? Thanks for all the help.

scale only 4 me

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60" span with a good 46, should work if you're able to keep it in the 10lb max range, you'd have a decent scale like flyer. Obviously, the lighter the better

Typical with any design, the further the motor gets away from the center of drag mass, the more you need to correct with thrust angle, be it up/down/right or left.
You can kinda see it that first picture, being a pusher, and the engine right over the wing, it has a few degrees of up thrust, or positive incidence relative to the wing. I'd guess maybe 2-2.5 degrees would work.

Drawing building Plans?
Do you research, find as many pictures that you can and decide how detailed you're going to build it, Most guys, like me, build them to fly not enter a contest, so they go with what I call "pretty scale", That is with scale outlines, with small modifications to allow for good flying and water handling characteristics. Decide what you're building it for and go for it.

If no plans are available find a set of 3-views, like this http://www.aviastar.org/pictures/russia/be_mbr-2.gif The more accurate the 3-views the better. Blow them up to your scale and start figuring it out, and cutting pieces. If you've built enough kits to think you're ready to take on a scratch from scratch, you know how these things are put together and what goes where.

When I built my Kingfisher I took the 3 views to Kinkos, had them blow it up to the right size 4-500% what ever it was. Then I tapped it to the table and used tracing paper to draw the plans right over the 3-views, firewall, formers, wing bolt locations etc. I also cut a foam wing, which is way faster than drawing, cutting out and building with ribs. Trade off? Stronger but a little heavier.

It's a lot of work,, but worth it
Good luck

cpt nj

Hi wayne ,you forgot to mention lot's of STRUTS ,after I finish my PBM thats my next project .Do you have any building tips?

skater_719

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Well I'm planning to order all the wood within the next few days, and my only question is, with having such wide formers in the fuse, wider then any balsa I can find, how do you guys do it? Every other scratch I've built had formers thinner then the width of the balsa sheet. Should I just have the formers in two peices?

scale only 4 me

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I'd use light ply for the fuse sides and bigger bulkhead/formers.

Call around places that sell plywood to cabinet makers, not Home depot Lowes, etc.
ask for 1/8 or 3mm Bending Poplar, we in the hobby call that "Light Ply" same stuff, you can get a 4'x8' sheet for under $30 most times


(edit,, 3mm = 1/8" ,not 5)

skater_719

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How would you recommend finding a place like that?

scale only 4 me

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You'll have to call around places that sell Moldings, Hardwood lumber, Woodworking supplies, etc.

Charlie P.

I have been harboring a Supermarine Walrus build in my mind but never got around to it. The landing gear hinges up to hang below the wing and would make a simple amphibious model.







http://www.ipmsstockholm.org/magazin...ail_walrus.htm

skater_719

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Alright, I am going to explain this as good as I can. Right now I'm trying to figure out the right dimensions, using that 3 angle pic and a ruler on the computer. I have figured that 1" is 8.85 feet in real life. But for some reason my head just gets really confused when it comes to doing the math, so can someone give me a simple formula to figure out how to get the right measurements for 1/10th scale. Right now im just working on compufoil getting some of the ribs figured out, and am hopefully going to get started on the fuse parts tomorrow. Trying to get all the plans finished by the time the supplies get here. Would there be any interest in a build thread, or even better, would anyone be interested in doing this project with me, so we can maybe share some different ideas on the design? Thanks for all the help!

scale only 4 me

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I don't think 10th is what you want for that 46,,,

You want to find your "Multiplier" weather you're scaling up or down

Based on the specs shown here http://www.aviastar.org/air/russia/be_mbr-2.php
Scaling down
Wing span 62' 4" (62 x 12 = 744" + 4" = 748" span 748 x 10% = 74.8" or 74 7/8"
1/11 th scale the multiplier 09.0909%,, 748 x 9.0909% = 67.9"
1/12 is 08.33333333% ,, 748 x 8.3333% = 62.33"
Looks like 12th scale get you in the 60 " range you're shooting for

Now if you want 60" exactly 60/748 = 8.02% of full scale

If you want to scale up from the 3-view you've printed out?
Let say the wing span on you view is 6", you want 60" so that's 1000% or (6 x 10)

It just the opposite of scaling down
A/B = C 60/6 = 10
A = Desired finish size aka 60" span
B = size on small drawing
C = Multiplier

scale only 4 me

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here is a place that will ship 32" x 48" (1/3 of a 8x4 sheet) pieces via UPS at 1/3 the cost of what most hobby places will charge
http://www.curvolutions.com/BendingPoplar.html#

p.s.
What's an 8x4 sheet??
This material comes 2 ways, normal 4x8 or 8x4, A typical 4x8 sheet has the grain running the long (normal) way, the 8x4 sheet has the grain running perpendicular or cross ways you what you'd normally see. Either will work for anything shorter that 4' in a model airplane app. The 8x4 is used to make radius cabinets and cabinet doors by Cabinetmakers,, of which I'm one.

joebahl

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Rcm plans has some sea planes to choose from http://www.rcmplans.com/ i hope one of the posts helps you skater 719 ps You can get alot of balsa here for 30 bucks and it weighs less. http://www.nationalbalsa.com/ joe

joebahl

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If you go electrict ivans plans are very light and not to hard to build http://ivansplans.com/ here is my short solent by ivans plans it is the 480 size with four motors on the wing .I started in nov and almost ready to cover. 99 inch wing and the fuse is abought 6 ft . I dont think any one at the lake will have one like it. lol If you do build the russian sea plane do a build thread so we all can see your handy work. Here is another site with alot of sea planes . http://www.seawings.co.uk/ joe

seaplane

JOEBAHL I purchased the same plans from Ivan, but I haven't started it yet. I cannot find any speed 480 motors. What are you using?
Seaplane

joebahl

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I am using jamera 480 bb s with gear boxes,but if i had to do all over again i would go brushless as they are cheap now even if you have to buy a esc for each one. I bought my 480 s from john swain at fanfare in the uk, but hobby lobby has long can 400 that i think you can use . john swain had a hard time finding me 4 of the ones he did. The jameras are faster so i had to drop a prop size from what ivan used . It is real hard to find 480 brushed motors any more and if i have a problem with one i dont know what i will do so i am already looking for extra motors just in case. It is hard to to find a esc too. Here is johns site at fanfare http://www.fanfare.f9.co.uk/contact.html joe

dicknadine

Simple glue 2 sheets together and get a 5" wide sheet. Not the full length, just long enough for the part. Practice- Practice

skater_719

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Well I decided to order the wood from nationalbalsa.com. I am going to do a mix of ply/balsa/basswod. But will try to get away with as much balsa as possible for weight and because its a lot cheaper. I'm going to shoot for 7lbs. I am hoping it will sit in the water somewhat scale like, and actually have a few inches submerged. I was considering glassing it, but don't have much experience with that so I'll wait for a smaller project to learn. Thanks for all the help guys, will post a build thread as soon as I have a few days off of work to get a good start.

skater_719

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And will 2 480 brushed motors really fly that thing? Thats pretty insane.