Bristol County Radio Control Club Forum

Access Hatch and Turtleback Skin

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Got more done today. Had worked yesterday on a different plane. I got the rear fuselage covered with some explanation for some wondering what I am doing. More text on the pictures. The hatch cover was a toss up for wood or foam. I like the better edge with wood on the seams. So that is what happened there.

I pre-rolled the Depron to help with the layup. It can be done with packing tape on the foam very easily also. Tape will prevent cracking. These parts were Polyurethane glued in place. The glue has a good working time to allow fitting.

The hatch cover stringers are layed over the existing edges on the hull. I use wax paper to help prevent it sticking together. Next is some sanding and to put a deck in the cabin area. I do not care to see a battery looking in the windows. I also have the wing saddles and wing bolt wood to install in place. Oh yes, small angle spray deflectors under the hull before the epoxy/glass work.

Cockpit Area Start

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I had a little slacking this weekend on the model. I worked on aligning the Access Hatch lineup and sanding. I have the lineup dowel in and need to put a magnet in also. Then I moved the cockpit perimeter forward 1 inch. The original Mars had the cockpit forward more than the later conversion JRM's.

After getting it were it should be I put a Depron floor in. It is not full depth as the big battery is under it. The sides were closed in and I started working around the dashboard. I guess I will have to put some gauges simulation on the control panel. I also have the throttles to put in too. I am not going to heavily detail the cockpit. Just enough.That is it. The seats were made with 3mm foam next. They are similar to the pictures I have. I use a small amount of hot glue on the foam. It works good and it allows me to move along.

Now I looked at the steering in the pictures. I had nothing around that would look like a steering wheel. I decided to make a pair tonight. I used 1/16" brass tube wrapped around a piece of pipe nipple to shape. Made the Y center and soldered it together. A pair of stanchions from 2 larger tubing sizes were made. The wheels are on axels and spin and settle back in place as the balance is low side.
Maybe I can find 2 plastic people I can make pilots out of with some putty reworking.

Got some more cockpit setup done today. Got to get the interior finish paint done then the windows glued in place. I can then tape it up until it is time to finish paint the whole plane.

Hull Anti-Spray Strakes
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Got the wing saddle mounted to the shape of the airfoil. I also have 2 wing mounting plywood gussets in place. Then I mounted small angles on the hull bottom to make the spray turn flatter to the water and less contact to the upper surfaces and props. The plans show these. I have now to spackle the whole plane with Spackle Lite and prep sand for epoxy glass to protect the plane from dents and creases. I think a few days at it will get it done.

Elevator Start
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I have to design the elevator for the early Mars. It has almost a straight trailing edge. The rest is close to Ivan's plan leading edge angle and the hinging edges. The early plane has what I determined to be about 24 degree dihedral also. This elevator has to be strengthened due to the 2 rudders creating twisting forces on the elevator.

The V area attached to the fuselage needs to have special attention for the mounting support also. I determined that the Y control pushrod for the elevators may not be to bad to create and connect. The rudders will be harder to fabricate and I have to get a bellcrank under or inside the elevator. I will braze up fittings if needed. I will still have to plan as I go along figuring it out. The airfoil has plenty of room inside. The ribs are pink Z-fold around 5/16" or 7mm and the perimetor is all wood. The cover skin is going to be Depron 3mm foam.

Great progress Bob!
Also great to see you are building the two rudder version... awesome looking and certainly unique!

Rudders
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Today I framed the rudders out. There is a combo of hard wood and balsa. The 1/8" balsa outer perimeter shape is cut in multiple pieces so the straight grain works without spltting. The both sides will be Depron after the controls and hinges are installed. The final thickness of the rudders is 3/8" inches. I pinned it together and placed it on the plane. The angles are not setup perminent yet and I am sure they are off with pins holding it.

Custom Rudder Horns
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Got some work done today on the rudder horns and hinges. I can cover the outsides tommorow. I have to make the horns for the elevators and then I can hinge those up also.

I spent most of the day sanding every edge on the assembly. The whole tail assembly is getting to the finish now. The tail is 36 inches span.Toward the end of the day I got the tail saddle in place. I still have to connect the cables and put in the final mounting. Shaping up. It is 1 month since I started. Next week I can start the wing parts.

I can just about say I am done with the tail section. All the controls are connected and the assembly is secure with 2 dowels and 2 screws holding it in place.

I just happened to find an automatic bailer in my old boat stock. It says $2.95 on it. I checked and they are up a couple bucks more. I am going to install it in the hull in the deepest part of the V near the step.
http://www.aeromarinerc.com/index.ph...emart&Itemid=1

I got all the wing rib patterns cut out today and will start the wing construction tomorrow. I found a new Depron type foam that came out in RC groups and it is 1/4 inch very high quality. I ordered a box of it and I am thinking of using it as the wing skin beyond the balsa leading edges. I'll know when it comes in if it is a go..
http://www.modelplanefoam.com/
The story is here on the foam.
http://www.rcgroups.com/forums/showthread.php?t=1533245

More pics coming on the wing soon after I get into it further along.