I have started building a twin hull flying boat called Savoia Marchette S55X first built in 1933. It is a small plane with a 40 inch wing span. I am building it from Carsten plans which I had purchased over 30 years ago while I was still flying control line. The plane is originally supposed to be control line with a 15 to a 19 nitro engine. I am converting it to a 4 channel electric.
The wings and hulls are built up balsa with balsa sheeting. You can refer to the drawings I have attempted to attach for a look at the plane.
I will try to capture the construction as it progresses along.
A very cool subject, Bruce! I hope this means you'll be joining us for some float flying next year.
BTW, what, if any, changes need to be made to a control line design to concert to RC? I know some control surfaces need to be added, and perhaps the fins straightened, but are there other considerations like wing section, tail surface areas, AOA of wings and motors?
Oh, Hey! Now that you're making it electric, you can make it the twin it was always meant to be :)
Hooray!
You've started your build thread! I'm really looking forward to reading about such a neat subject! Congratulations on being invited to join the Robert Pike and friends Float Flys!...they're fun!
Robert, I plan on replicating the scale control surfaces for RC purposes. So this means the ailerons, rudders and elevator will be similar to those proportions shown on the drawing. Would you suggest changing any of these? You may have a point about making it a twin engine, but I think for now I will just put a dummy free wheeling prop on the rear. I also plan on adding some dihedral to the wing. (Because as a control line model the wing on the drawing is straight.)
Does anybody have any suggestions on how I can make the plane water tight? What type of finish should be applied? Suggestions and comments would be helpful.
Thanks, Bruce
Congratulations Bruce, nice choice.
I would suggest you consider increasing it to around 52" wingspan. easier to build with bigger parts.
You can water proof with Polyurethane or epoxy inside or you can fiberglass outside.
I agree with Robert regarding two motors.
Being pull and push and counter rotating you can use smaller motors and offset torque effects.
Looking forward to the blog.
Jack.
Thanks for the information on waterproofing Jack. I wish I had discussed this build before I started, because your suggestion to make the plane bigger makes sense. Unfortunately I have already cut the parts and kitted the plane at the original plan size.
Now that two of you have suggested using two motors, I will definitely give it some thought. Perhaps someone with multi-motor experience could share their knowledge with other members at a future meeting on what is needed to accomplish such an installation. I would find such a presentation helpful.
As you can see from the photo I have started construction of the twin hulls. FYI - I call those things attached to the keel 'formers' and 'bulkheads'. What do I know?
Bruce a "bulkhead" is solid and a "former" is open. In my Northstar both are used.
I will make that a subject for our next pilot's Meeting. All about multi engines.
Setting up twin motors is nor very difficult. I have one that will be maidened in Spring.
You just have two ESc's and two Motors, you can use one or two batteries.
Mine have counter rotating propellers so torque issues are largely eliminated.
Jack.
Jack, Thanks for the clarification on the bulkhead/former matter. My bulkheads will be modified to become formers in as the plane construction progresses for the purpose of putting batteries and related equipment into each of the hulls as deemed necessary.
Respecting the proposal for the next pilots meeting, would it be possible to have the multi-engine presentation at the March Pilots Meeting instead of the February meeting? Unfortunately I have other commitments and will not be able to attend the February Meeting. I really wouldn't want to miss it.
Thanks,
Bruce
Bruce,
What an interesting aircraft you've chosen! Googled it and found many S55s made S. Atlantic crossings back in the 20's when this was still a risky business for most airplanes. It's history lays to rest any concerns about the unusual design having questionable airworthiness. I've attached a photo of the only surviving S55 which is in a museum in S. America. It has a particularly distinguished history and the coolest paint scheme! Finding out about unusual airplanes is always fun!
The unusual twin hull design has me wondering what you'll do about the battery(ies)...
Bruce can use two smaller batteries, one in each hull.
That is a really neat colour scheme.
March it is.
Jack.
Or a single battery in the center section of the wing... if there's room.
While deferring to the master I see some negatives to Robert's suggestion.
The centre of balance will be high.
You may have to beef up the wing structure.
You may not have sufficient room to move the battery forward for balancing.
Jack.
Just want to say Bruce that this looks awesome. Cant wait to see it.
I was in my "Think Tank" this morning and I though two inrunners would work great for this model???
Jack.
Quote from: Papa on January 17, 2014, 09:28:01 PM
While deferring to the master I see some negatives to Robert's suggestion.
The centre of balance will be high.
You may have to beef up the wing structure.
You may not have sufficient room to move the battery forward for balancing.
Jack.
Yah, yah.... Keep shovelling... :)
Centre balance? Nah.
Beefing up the wing? Nah
CG range? Well, you're probably right ;D
In my life one out of three ain't bad.
Jack.
I have had some distractions to deal with, so now I am back at the project.
After covering the sides of each hull, I have now built a dry dock cradle to support the hulls where required and I can construct the rest of the plane on them.
I will now proceed to construct the wing and get it mounted before adding the blocks to the hulls and shaping them into the wing. I also have to plan for a couple of access hatches and arrange for the servo installations.
The photos depict the cradle and the covered hulls. The beer was placed in the picture so that it is possible to relate to the size of the model. The contents of the beer are now gone. (Another distraction)
Thanks for the construction suggestions. There is likely room in each hull for a pretty good size battery or a larger one could be placed within the centre of the wing section between the hulls. I'll cross that bridge as construction progresses. This is where I would appreciate some further consultation.
Quote from: bweaver on January 29, 2014, 04:57:53 PM
The beer was placed in the picture so that it is possible to relate to the size of the model. The contents of the beer are now gone. (Another distraction)
Thanks for the construction suggestions. There is likely room in each hull for a pretty good size battery or a larger one could be placed within the centre of the wing section between the hulls. I'll cross that bridge as construction progresses. This is where I would appreciate some further consultation.
Glad you're enjoying the beer along with the build! Helps wash down the balsa dust.
For what it's worth, I think Jack's two battery, one in each hull suggestion is likely to be the only way to balance this model without ballast. Perhaps you could make the final decision after the airframe's done and you can estimate better where the battery(ies) will have to go to avoid ballast. I'm betting Jack is right.
Jack is always right!! :-)
Thanks Simon, It's nice to have a fan, your money's in the mail!
For the sake of correctness, Bruce can you edit the title and spell Marchetti with an "i". Alessandro would be most pleased.
Jack.
I never could spell. I have corrected the segments of the thread that I was permitted to modify.
Thanks for the advice for balancing the plane. I feel there will be allot of room for the varying placement of the esc(s) radio, battery(s) etc as the construction continues.
Sorry to be such a PIA.
Have you decided on one or two motors?
Here's a picture of Laddie Mikulasko's Dornier DoX.
These are all can motors, one in front and one behind in each nacelle.
It can be done. This model flies well but very scale like.
Jack.
Jack, I was initially thinking of only one electric motor because I have one that would be suitable.
I need to have some further advice on the use of two. For example, I really don't know how I would determine the motor sizes, battery(s), esc's, etc., because I have had no experience in this area. I really need that multi-motor session coming up in the March meeting to get a grasp on this end of things.
I see no problem mounting two motors on the pod, but for determining the power requirements; I wouldn't know the weight of the model until I get it pretty well constructed, covered with balsa, servos installed, etc. Then because I want to make it water tight, I don't know if the finish applied will add allot of weight too?
I'm definitely not counting out two motors. But the decision will have be made at a later date.
I'll start the discussion.
http://www.hobbyking.com/hobbyking/store/__17345__NTM_Prop_Drive_Series_28_26A_1200kv_286w.html (http://www.hobbyking.com/hobbyking/store/__17345__NTM_Prop_Drive_Series_28_26A_1200kv_286w.html)
This would be a small diameter but two would put out about 450 to 500 watts. Two props 8x4 would look about correct. Two 20 A SEC's and two 4S batteries. It's a 40" span and probably come out around 3.5 to 4.0 Lbs. Two motors are more efficient than one large one of the same combined size.
Jack.
Jack.
Yikes! 3.5 to 4 lbs for 40" span? I hope not. I'd start with the wing area and a desired wing loading to determine weight goal. Then choose motors based on that.
Looking at the cord to span ratio I estimate about a 300sq/in wing area (you can correct that estimate with the real wing area). That's 2.08 square feet. With an aircraft of that size and type I would aim for 18 oz/sqft wing loading MAX. At that, the final flying weight will be around 36 oz., or 2-1/4 lbs. I would go for a power loading of 100w/lb for a power requirement of 250watts. I think that would be plenty. That's two 125w motors. It would be nice if these could be run off of 1x 3 cell battery mounted in the center section of the wing, but, as Jack pointed out, you may have CG problems. However, looking at the aircraft layout, those pontoons don't extend out ahead of the wing very much, so I don't know how much help two, say 1000mah, 3 cell batteries are going to help.
I'm back at the construction of the Savoia Marchetti S55X.
I have cut out the ailerons and will be installing the servos. Which side of the wing should the control rods exit? Top or Bottom? and how do waterproof the servos and control rod areas? Any help would be appreciated.
Bruce
Cool! I'm glad you're back at it, Bruce!
I'd put the control rod exits on the bottom. First, because it looks better, but also because then any water that does get in, simply drains out. If you put the holes on top, water will go in and never come out.
I just leave a hole for my servo arms to exit and hook up a direct pushrod (on my M-33). It hasn't cause me any issues. You could create a fairing that would help to keep the water out. I would also suggest that the area where the servo sits be closed off from the rest of the wing. That way, if the plane does go under, the water will stay in that one area and can easily drain out through the hole.
My preference would be to come out through the top. But if I remember correctly this is a high wing model so the servos are far from the water. It may not matter that much. You can silicone the seams and use shrink film to reduce the possibility of casual water getting in. Otherwise you would have to use the new water repellents such as http://www.hydrobead.com/#!consumer/component_41229 (http://www.hydrobead.com/#!consumer/component_41229)
http://www.rustoleum.com/product-catalog/consumer-brands/neverwet/neverwet-kit (http://www.rustoleum.com/product-catalog/consumer-brands/neverwet/neverwet-kit)
Jack.
Correction now I agree with Piker. Bottom for drainage.
Jack.
Thanks guys.
Getting on it. I will be posting photos as the construction progresses.
Bruce
A belated reply to an intriguing thread. spurred by seeing a swarm of S55s in the DVD Porco Rosso (should be required viewing for all Italian seaplane fans). Simply wanted to post my agreement with Jack and Rob based on the aileron servo mounting on my Sebart Macchi MC72. Slight twist on the usual servo in the wing configuration. This model uses a low profile, waterproof servo mounted with the drive shaft face of the servo exposed and the servo sealed into the wing with silicone.
The construction finally continues!
I have constructed the two booms and elevator stabilizer. They have been attached to the twin hulls after making a foam wing and tail surface incidence template to guide this step.
The elevator and 3 rudder/vertical stabilizers will be attached next, once I have finished attaching the hinges. Then I will attach the elevator with hinges as well.
I see what a number of you meant, when it was said that this aircraft is likely to be tail heavy.
As you can see from the photos, I have lots of room in the hulls to mount batteries and servos to counter this problem. What do you think?
Bruce
Looks great Bruce. Dry fit your servos and batteries just to be sure but it looks like lots of space. Weight distribution should be no problem unless you put servos in the tail. The twin motors on top will look very smart if you go that route otherwise one tractor motor up front and a dummy free wheeling prop in the rear might work.
Jack.
Looks fabulous Bruce. Really taking shape.
No one can call me a fast builder. As a matter of fact, no one has ever said that or is likely to say that about me in this regard, or any other.
As you can see from the photo, I completed the control surfaces and temporarily installed them.
I have also cut the aluminum motor mount pod which has yet to be bent and covered both sides with 1/16th inch plywood. Once that is done I can secure it to aircraft and proceed with planning and finalizing the motor(s) and ESC installations and cowl for the motor mount area. I believe this will be best the place for air cooling the ESCs as there will be room between a front and rear motor to secure them in this vicinity.
I can also proceed now with the aileron servo installations and make water tight compartments for these in the wing (bottom). I can also rough in the servos and control rods for the elevators and rudders. I plan on securing the elevator and rudder push rods adjacent to the inside of each of the booms. The three rudders are going to be linked together for control movement purposes and pushed from one rudder at the side.
Once this is done I can finish covering the wing and finishing off the hull construction as well. I will have to build a water tight compartment(s) and hatch(s) for the electronics and battery(s).
Anyway, that's where the project is so far. A little progress is better than none at all.
By the way, I am having a great time reading all the other construction information that is posted in the forum. What a great resource and a tremendous source of encouragement. Everyone, keep up the building.
Any suggestions on my project are welcome.
Bruce
Hey Bruce I think this is a unique build thread and i enjoy it immensely. I love models with character and this one has it in spades! Building fast or slow is not an issue. Even building skills are not an issue. We all build to our own level of skill and it's not a competition. The only question is "are you having fun"? If you answer yes than all else is of no importance. If you answer no, find another hobby.
Michael builds fast, Colin builds slow and is anal about detail, Robert builds medium fast but has a thing about good woodwork and proper joinery. The one thing they all have in common is the huge smile on their faces when they talk about their current build. That's the secret so you are right on track and believe me an awful lot of members envy your building skills and wish they could do the same. Little do they know that starting is the hardest part and it gets easier as you build.
Jack.
I have to bend the motor mount aluminum pod precisely before mounting and attaching it to the aircraft. Does anyone know how to bend sheet aluminum precisely without using a sheet metal brake? Or, does anyone have a sheet metal brake or know anyone that does sheet metal fabrication?
Bruce
If you use a sheet metal vice-grips like this with a vice you can do some pretty neat bending. Jack.
(https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQRFeozv5SF-k7bmAhNYFeRFJlXgbyL3rpJYL7kMbTiP70XapBB)
Great Jack. I can see that that will work for me.
Bruce :D
http://www.leevalley.com/en/wood/page.aspx?p=66804&cat=1,43456,43407
http://www.leevalley.com/en/wood/page.aspx?p=32011&cat=1,43456,43407
Hi Bruce. I forgot but I have this metal bender from Lee Valley and it is very accurate for our kind of work. I also found their sheet metal vice and it may be a better quality than the vice-grips.
Jack.
I'm with Jack on this one (for a change ;D)
Bruce, your building project is progressing nicely, and it will be a fabulous scale model when finished. I'm really looking forward to seeing it fly!
Thanks guys, I will be going the Lee Valley route for the sheet metal bender. Bruce
;D I have bent the aluminum motor mount pod, drilled the mounting holes into it and glued the plywood framing pieces to each side as well.
Upon reviewing the drawings, there appears to be sufficient room for mounting two electric motors and perhaps installing the two ESCs in the cowl space provided.
Looks great Bruce. It's so unique, I love it.
Jack.
I have turned the heat on the gluepot, which has made me get off the pot and proceed with the project.
I have decided to keep it simple and use only one tractor motor and ESC with a dummy pusher propeller. Now that I have decided this, I have modified the hull bulkheads to accommodate the batteries and wiring. The servos and control rods are installed.
The plane should end up weighing between 2.75 and 3 lbs. It will be powering with a G10 and two 3 cell 1000 mah batteries. One battery will be installed in the front of each hull for CG purposes.
I have been tinkering with using a tallboy beer can for engine cowling purposes. We will see where that gets me.
Next will be finishing the wing covering and hulls. I have to make a battery hatch for each hull and a hatch under the motor mount pod in the cockpit area for access to the electronics.
Taking one step at a time.
Looks great Bruce.
Jack.
Looks wonderful, Bruce!
I see you even have the servo's installed! You'll be finished in no time.
I like the beer can approach. It reminds me of an old friend, who I knew in the early days of Electric flight, who used the metal and graphics from a Miller can to created the top of the front of his Heath Parasol model. It looked so cool.
While the beer can is a little short, the circumference of the beer can is the exact size required. I plan on beefing it up and securing it with foam. I will make a plug for the rear portion that will house the free wheeling dummy prop and make the correct length of cowling. With the ends of the beer can cut out, the can feels like there is no weight to it at all.
Almost forgot to caution all, that I nearly burnt the plane down by grinding off the ends of the 6/32 screw ends holding the engine pod on. Don't do that at home! Next time I do some grinding, I will be shielding the balsa from the cast off sparks.
I have roughly crafted the battery hatches for the hulls. They have to be carved and magnets will be used to hold them in place.
Next steps include finish forming the hulls and making the centre cockpit access hatch.
Spring is coming quickly.
Quote from: bweaver on March 03, 2015, 11:58:39 AM
Spring is coming quickly.
I admire your optimism, Bruce! Especially today!
This must be the first flying boat powered by licorice allsorts.
LOL
Jack.
Bruce is fuelled by liquorice allsorts. The plane will be battery powered. ;D
I can sense the ice melting as we speak!
Keep going, Bruce. It looks fantastic!
Carving and sanding..........
After the heckles I received at the last pilots meeting, I have really cut and shaped and sanded and sanded.
I have thought again about using two motors as apposed to the one G 10 as proposed at the meeting. (Here I am on the fence again.) ???
I am considering using two of these motors View Product (https://www.hobbyking.com/hobbyking/store/%5F%5F22849%5F%5FTurnigy%5FLD2816A%5FBrushless%5FOutrunner%5F1350kv.html). Each equipped with an 18 amp ESC and 3 bladed 8 inch prop. The HK product information indicates that the motors will apparently provide a maximum of 120 watts each. I can provide a 1000 mah 3 cell battery to power each motor individually.
The wing area is approximately 325 sq inches. The weight of the unfinished plane now including the two motors, two ESCs and two 1000 mah batteries weighs in at 2.18 lbs, (35.2 oz). These are not mounted yet or wired. I think I can bring the finished weight of the aircraft in at close to 2.75 pounds.
Appreciate any thoughts.
Hi Bruce, I don't think that motor is your best choice. I think you may have trouble mounting a prop on it. It looks like a slow flyer with an "O" ring for the prop.
Here is a better choice.
http://www.hobbyking.com/hobbyking/store/__21478__NTM_Prop_Drive_28_26_1000KV_235W.html
You would need the accessory kit. We bought some for our gliders and they look to be very well made. You would have the ability to get more watts by going to 4S which the motor will take.
If you go two motors remember the second prop has to have a coarser pitch as it will be running in disturbed air.
Jack.
Bruce,
I am very partial to the E-max CF 2822 outrun bell motor which is a 150 watt motor, have a 3mm shaft. I have flown several airplanes on them (3 cells). They are powerful, light, small and inexpensive. I do not see it in the current HobbyKing website but I have 3 new ones if you want to try two. I have flown a 42" Cessna Skylane, a 60" Fournier glider (.049) and a Cessna Skymaster 332 (36" span) with a single motor in the front and a free wheeler in the back.
The closest one currently available on the Hobby King website is the one listed under the 28mm-34 mm outrunner motors FC 2822 1200 kv.
I can bring them to the next pilot's meeting if you are interested in looking at them.
Frank
That would be great Frank if you would bring them out to the next meeting. Do you know what size ESC I would require for each? Personal message me with your price. Thanks Bruce
Bruce
A 15-20 amp ESC. I will bring them, have a look at them, use them if you like them. If they are fine...$8.00 a piece. If they are not powerful enough I will take them back at no cost. They are brand new and unused. No money changes hands until the maiden flight proves they are good enough for your project. Just in case my opinion was wrong! :D
Frank
That's a deal Frank, but I will definitely straighten out with you before its' maiden flight, because while I am really sure that it will fly, I have to be positive that it will float first. ::)
Bruce
Bruce,
re your : ".... I have to be positive that it will float first."
Right-side up! If not, reduce the prop size by a factor of 10 to compensate for the increased density of water versus air. Flying boat... motor boat. What's the difference. :D
It will fly.
Frank
Quote from: Frank v B on March 22, 2015, 09:28:45 PM
Bruce,
re your : ".... I have to be positive that it will float first."
Right-side up! If not, reduce the prop size by a factor of 10 to compensate for the increased density of water versus air. Flying boat... motor boat. What's the difference. :D
It will fly.
Frank
I agree the Savoia will fly...or float...right side up...however because of the thrust line I think there might be a difference...and upside down may prove risky in air or water!
Trying to fly it upside down (especially if it's flat bottomed wing...err flat bottomed when it's right side up) will turn it into a lawn ornament . For the same reason, reducing the prop to 1/10 and trying to navigate upside down on water will turn the craft into a submarine!
I agree with Frank on this part...fly or float right side up!
:P I'm bringing out the Sovoia Marchetti S55X to tomorrows build session in order to get some tips to finalize it. I have been in a funk with it and now it is time to get out of it. Moving on.......
Excellent, Bruce! I'm looking forward to finally seeing it.
Since attending the build evening at Col Mustards, I have completed the electronics installation. Everything fits and everything works. Now finish covering, water proofing, building cockpit cover, hull hatch covers and attaching control surfaces.
The ESCs are mounted under the twin motors. They are not water proofed yet. They are held in place with Velcro strips. When it is time to take to the water, I will bag these components then re-secure them. Moving on......
Bruce,
Any luck finding a Moretti or Peroni can for your motor cowling? The model really should have as much Italian content as possible! ;D
I can't remember...did you use a regular size beer can or a tall boy? I'll see what I can find for you by next class!
It's a tall boy that I was planning on using.
As you can see from the photo, the tall boy just isn't quit tall enough on its own. I will have to do some modifications by extending the can or using two cans. Going to a can of Italian origin sounds like a solid idea to me.
;D
:D
It is finally ready for the sky. (and water)
All control surfaces are connected, canopy completed, only a couple of decals to install.
With a 1600 3S battery installed in each of the hulls, it balances out pretty well right on the specified CG. The hull battery hatches are secured with a dowel at the front and magnet at the back.
For those that care, the beer can was reduced to make the front cowling only and painted silver. The remainder of the fake motors, cover and rear engine cowl is made from shaped balsa.
For flying off water, I intend on scotch-taping each of the hatches and canopy to prevent water from entering the aircraft.
No more excuses. ::)
Wow! It looks beautiful, Bruce! Congratulations!
You did a fantastic job on the building. I hope it flies as good as it looks.
Stunning! Congrats Bruce
Great job Bruce. Looks awesome.
Fantastic!
That shows a great deal of work in the details!
Beautiful! :)