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Old Oct 08, 2009, 08:07 PM
mcg
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1912 Donnet-Leveque biplane kitbash

The 1912 Leveque has been the subject of several build threads on rcgroups and elsewhere. Here are some I followed with interest:

http://www.rcgroups.com/forums/showthread.php?t=334865

http://www.rcgroups.com/forums/showthread.php?t=326333

http://www.rcgroups.com/forums/showt...81#post9507981

http://www.modelaviators.org/2009/Videos/2009Videos.htm

http://www.modelaviators.org/

The last two links, including the flight video of the Leveque, are on the club site for the Kennebec Valley club in Maine.

I am building a Leveque now, but I am not going to attempt a detailed build thread because we already have several. Instead I will document some things along the way that are departures from the kit.

It seems everyone who builds this aircraft kitbashes it to some extent. Megowcoupe shortened the interplane distance. Paul Flohn, who built the Leveque in the video, added a water rudder and what appear to be watertight hatches. DW and Silverpoz produced extraordinary scale details. Sperry built his with scale features from a later era, as an FBA, and minimized the dihedral.

I understand several builders have experimented with moving the step aft, in an effort (not clear to me if it worked) to get the plane to ROW.

Most of the design modifications in my Leveque were intended to make it easier to build.

The kit is currently available from Penn Valley, here.

http://www.pennvalleyhobbycenter.com...413leveque.htm

Michael
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Old Oct 08, 2009, 08:34 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
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I'm still screwing with mine after I moved the step aft a bit- still won't ROW, but it looks a bit closer. Don't see the need for a water rudder though, the rudder is very close to the airblast.

I'm kicking around going to a geared Fakeout setup (12 mm Feigao), although I might try one of the cheapie outrunners as well. I'm betting that there are two problems. One- the mount on my airplane is too big- it's got too much airdrag. Two- I think the Speed 300 is a bit heavy and since it's pretty close to the cg, going to a lighter motor shouldn't change things too much. My airplane actually has the batteries fairly far back.

If I have a shot, I'll report back if going to a lighter setup makes the airplane a bit closer to ROW.

Sam
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Old Oct 09, 2009, 06:53 AM
MaineFlyer
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Augusta, Me
Joined Feb 2005
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Paul's Leveque

Interesting thread! I helped Paul set up his brushless motor and ESC. I also made the first flight with the plane on Oct 11, 08 at Lily Pond. It would not ROW so we hand launched it. Later attempts by better pilots than I also failed to get it to ROW. To date, that was the best flight it has seen. The weather was perfect - not any breeze at all. Unfortunately, as I was flying the plane, I didn't get any video that day!

Over control was the biggest issue Paul has had since. Needs a very gentle touch on the controls. Paul did add a water rudder and a hatch in the front for the battery.

The info below is from the KVMA newsletter July 08.
"Paul Flohn's 1912 Leveque Flying Boat
The original was a French design and first flew on March 15, 1912. It had a
31 ft. wing span and was powered by a 7 cyl. Gnome 50 hp. Engine.
Paul acquired this RN kit from Vern's collection and started building in May
while recuperating from a broken foot. This model has a 33 wing span and
will be electric powered. AUW will be approx 13 ozs using a Emax
BL2210-25 brushless motor and an Electrifly 3S1P 640 mah Lipo battery
with a 5x3 3 blade prop. Our initial tests show about 100 watts of power
which is far more than needed for a model of this size."


There are a few photos of the building process in the Projects - 2008 section of the web site mentioned above.

I hope to see more on this as the projects mentioned here are finished,

Joe
KVMA Newsletter Editor and Webmaster
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Old Oct 09, 2009, 09:04 AM
mcg
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CAD, hull changes

Thanks for checking in and for your expertise, Sam and Joe.

In the late 1980s, I bought this kit in its original version, as an R/N model. I had built and flown their FF Bleriot and liked that kit. But the Leveque turned out to be problematical.

Note how the R/N hull is built from the photo of David's build. The plan suggests as a first step gluing the formers to one of the fuselage's two slab sides. This side with its projecting formers and the opposing side are then supposed to be curved, united and glued. As you can see in the photo, David used clamps to help accomplish all this.

If the formers are glued to the first side at a perfect right angle, then bending and joining to the opposite side will automatically produce a slight cusp in some of the formers. This is a setup for a break. When I tried applying pressure to curve the two fuselage halves together, one former near the bow cracked loudly. I should have used steam.

I was able to patch up the hull and continue, but for some reason the wings did not turn out just right either, and in the end I sold the unfinished model to another modeler at a garage sale for $1.

When an R/N Leveque turned up on ebay around 2004 I decided to take another swing at it. This time, instead of opening the box, I forwarded the kit to Glenn DelConte in Georgia. Glenn is "Fanman" on rcgroups. He is a CAD expert. He re-engineered some features of the model and had it laser cut. The kit I am now building reflects Glenn's insights, ideas and refinements.

I told Glenn about my frustration with constructing the fuselage, and he came up with a different way to approach it. In his verson, the cockpit has a floor. The formers are aligned and glued to this floor, as shown in the photo. The cockpit floor makes the fuselage assembly a more symmetrical job. There is no tendency for the formers to bow and then possibly crack -- an underlying problem with the conventional method. The floor panel also provides a platform for the rc installation.

The plan in the background shows the installation of an AXi 2204 brushless outrunner.

Michael
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Old Oct 10, 2009, 07:43 AM
mcg
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Motor mount plate

Sam has an excellent point about the motor mount plate. It adds a big frontal area -- a plywood kite -- high above the step. Maybe there would be a way to replace this plate with an open space frame type of motor mount.
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Old Oct 10, 2009, 09:03 AM
mcg
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Jigs and fixtures

The idea here is to make a set of twelve 90-degree angle brackets, and arrange them as tangents to the curve of the fuselage at each former.

Two reasons. First, as jigs, the braces can be used to align a sanding tool (popsicle stick) to correctly bevel the edge of each former where it greets the fuselage side. We should probably have thought of this before we did the laser cutting, but we did not, so it is a sanding issue now.

Second, as fixtures. I would like to assemble the fuselage as completely as possible, and then paint the joinery with penetrating aliphatic glue ("Superphatic").

In this instance it is also necessary to pre-form the steamed fuselage sides, and then let them dry in place.

We have reduced the thickness of the fuse sides from 1/8 to 1/16.

Steel corner braces cannot be used as-is. They are strong but they do not form a right angle -- they are always off by a few degrees. To get a true right angle, a balsa stick is thixed to the steel, and then sanded with a True Sander to get a true 90 degrees.

The braces are secured to the building board with small diameter screws, so that there is some freedom to adjust each brace's position before tightening down the screw heads. Commercial versions of these braces are available from SLEC with slots instead of holes.

http://www.slecuk.com/catalogue/info_SL054_R.html

There is also a superb system of this type from Airfield Models using magnets instead of screws.

http://www.airfieldmodels.com/galler...aper/17679.jpg

I found a teapot at the hardware store that has a two position whistle, so the pot can be left open (and silent) for the steaming operation.
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Old Oct 11, 2009, 06:29 AM
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MCG thats a Kettle, a cooker hob kettle............ and very new, clearly never had to share a cooker with working pots and pans let alone a frying pan ..then they tend to look more like a old glow engine
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Old Oct 11, 2009, 05:30 PM
mcg
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Thanks, Airboat. A cooker hob kettle it is. Hope it works. Michael
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Old Oct 22, 2009, 06:35 PM
mcg
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Sanding and steaming

To sand the edges of the formers, I made and used the 1/32 ply sanding stick shown in the photo. Each angle brace is screwed down at a tangent to the curve of the fuselage, so it establishes the correct angle for sanding the edge of the former.

When the formers were finished, I moved the whole contraption into the kitchen, and steamed the fuselage sides, mostly near the nose. The sharpest and most troublesome curve is between the first and second former, so this is where I applied most of the steam.

While the wood was flexible, I made it conform it to the shaped curve of the white coffeepot. (Wearing garden gloves for this project.)

Finally I mounted the fuselage sides in the fixture, where they are finally locked into the actual shape of the hull. No glue yet -- thought I should wait for the thing to dry.
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Old Nov 03, 2009, 04:35 PM
mcg
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A couple of additional changes from the kit. A keel has been added. The fuselage sides were drawn and cut to include the upswept curves to the empennage. In the R/N model these were separate pieces to be appended.

Here is a photo of the 1912 Leveque on the step. It managed this with a 50 hp Gnome rotary. The original hull was slightly convex, in some sense a tunnel hull. Art Reiners' step on the R/N model is very different. It is triangular in form viewed from the front. Maybe it cuts the water rather than planing off on it.
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Old Nov 03, 2009, 08:45 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,716 Posts
Hi Michael

I'm doing a little speculating here since I've been lazy and still haven't remotored the airplane yet. But Joe's experience shows that there's a design problem with the hull- if 100 watts isn't able to blast the plane off the water- it's stuck pretty well. I'm thinking of going the other way- a bit lighter to fix the problem. What I've noticed when taxing back to shore with mine is that it seems pretty close to getting off, and I like the power match of the Speed 300 with the airframe, i.e. about 30 can watts or so. I'm thinking that somewhere around 40 brushless watts should do it- maybe less, especially if coupled with some weight reduction.

Sam
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Old Nov 04, 2009, 07:01 AM
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Megowcoupe -

Out of curiousity, where is your CG relative to the step ?

I'm just starting my build and was hoping to correct many of these problems I'm reading about before I get too far along

Richard
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Old Nov 04, 2009, 07:56 AM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
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Hi Richard

I'm flying the airplane with a cg about 3/32" in front of the spar on the lower wing. It could probably go back a smidge. Bear in mind that the step on my airplane has been moved further back- it's 5/8" in back of the main spar in the lower wing.

HTH

Sam
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Old Nov 04, 2009, 10:22 AM
mcg
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This is a build thread for the Macchi M-5, a somewhat similar design.

http://www.rcgroups.com/forums/attac...9&d=1156191957

This photo of the step structure appeared in the Macchi thread. Notice the inverted hull.

In the US, the tunnel hull was patented in 1914, so the patent may have been filed around 1912. Tunnel hulls were evidently "in the air" in that epoque.

In any event, I am thinking about inverting the hull, in the manner of the Macchi M5.

It would be fairly easy to make the necessary mods at this point. If it didn't help the ROW, well, at least it would produce a somewhat more faithful scale model of the Donnet Leveque.

My thought is, in "modernizing" the hull design for this kit, maybe something important was lost: the tunnel.
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Old Nov 04, 2009, 10:47 AM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
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Possible. I'm assuming that the designers back then had figured out that suction was a problem- and by creating a tunnel- air would be funneled in to help break that suction. We have a worse problem with our models because relative to size, water surface tension plays a larger role.

And like you said- it'll be more scale like, and you're clearly taking a lot of care in your build- far more than I did!

Good luck!

Sam
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