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Baby Ringmaster Scratch Build
Topic Started: Saturday May 2 2015, 09:57 PM (902 Views)
Tony Leong
Avid builder of models
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Found and down loaded the plan for the Baby Ringmaster from the net. Having a couple of Cox 049 radial mount engines lying around doing nothing so I thought it would be interesting to build one to accompany my Baby Flitestreak - which has already logged so many flights its beginning to show the wear.

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As usual, the initial task is to extract and produce the print wood patterns for transfer to wood before cutting to produce a kit of parts. A pleasant afternoon of work produced two kits of parts. It doesn't take much more effort to produce two kits than to produce one. I will build one and keep the other for another time.

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Edited by Tony Leong, Saturday May 2 2015, 11:38 PM.
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Tony Leong
Avid builder of models
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It was necessary to make several modifications. I shall be using a Cox engine without a radial tank and because of the shorter length, I extended the nose of the Baby Ringmaster to make up for it. I had built a pair of Keil Kraft Fireflies some time back and something I had learnt is that the 1/4" balsa fuselage commonly used by such designs have the tendency to break at the nose just before the leading edge of the wing and at the rear just aft of the trailing edge of the wing. When building my Baby Flitestreaks, I had 1/32" ply doubler cover the entire length of the fuselage and they have survived numerous crashes intact. For the Baby Ringmaster, I shall have the 1/32" ply doubler cover the nose of the fuselage until just after the leading edge of the wing. The remainder of the fuselage sides will be covered with 50gm fiberglass cloth and epoxy. The weight penalty will be negligible, as in the case for my Baby Flitestreaks with the 1/32" ply but the return in survivability highly desirable. Very important considering I seem to have a tendency to deep six my models :P :P

Other than the above mods, I shall be following the plan as is.
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Tony Leong
Avid builder of models
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Jeez, this plane is tiny. Here is the wing framed up and drying on the building board.

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Edited by Tony Leong, Tuesday May 5 2015, 01:09 AM.
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skling
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Nice build Tony. Enjoyed tracking your build!
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Tony Leong
Avid builder of models
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The wing framed up and ready to receive the control horn and centre sheeting.

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Modified fuselage to accommodate a tankless Cox 049. 1/32 inch ply doublers added to increase the strength of the nose and 1/2 x 3/8 bearers used to support the radial mount.

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Edited by Tony Leong, Wednesday May 6 2015, 06:59 PM.
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Tony Leong
Avid builder of models
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Bellcrank installed.
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Relief carved into the engine mount to allow the tank to be fitted.
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Fibreglassing of the fuselage. From my experience with the Keilkraft Firefly - which is quite similar to the Baby Ringmaster, the fuselage on these little puppies love to break just aft of the wing's trailing edge. Planes of this size tend to bounce on soft ground but if there is a break, 3 out of 4 will be the fuselage cracking just aft of the trailing edge. I can't remember the number of times I had to epoxy the same crack line on the Firefly. I hope the fibreglass will provide just enough strength to prevent it. On my Baby Flitestreaks, I had used 1/32" ply full length on the fuselage and it has made the plane remarkably durable.

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Edited by Tony Leong, Friday May 8 2015, 09:07 PM.
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Tony Leong
Avid builder of models
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Completed the centre sheeting. This completes the construction of the components. Needs covering and final assembly.

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While waiting for the Titebond to cure, I got busy with making water slide decals for the bird. Here is the fuselage with decals attached and fuel proofed.


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Edited by Tony Leong, Saturday May 9 2015, 02:45 PM.
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Tony Leong
Avid builder of models
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Hubba hubby. Time to break out a new roll of Coverite Microlite and get going with covering.

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Edited by Tony Leong, Saturday May 9 2015, 04:25 PM.
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Tony Leong
Avid builder of models
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Found that the pushrod I had installed is just a tad too short for making a z bend at the elevator horn. So what I did was an L bend and I soldered a keeper to the pushrod to secure the pushrod on the horn. Less hassle than to solder on a clevis stud to mount a clevis to the horn.

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And this ends the construction.

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I'll need to spend some time to repair the engine I intend to use on this model. A Cox Killer Bee II, its crankshaft broke during flight. I suspect that I may have weakened the shaft by over tightening the prop. In any case, I just received the replacement Killer Bee crankshaft. Should have the engine up and running in no time again.
Edited by Tony Leong, Tuesday May 12 2015, 06:01 PM.
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Tony Leong
Avid builder of models
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Well, here she is with tank mounted and all ready for her test flight. Probably tomorrow - weather permitting.


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Edited by Tony Leong, Tuesday May 12 2015, 09:18 PM.
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Tony Leong
Avid builder of models
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She flies nicely with the Cox Killer Bee II up front. This engine has been modified with the use of a Tee Dee cylinder and piston assembly and a high compression Nelson HD glow head. Initial flights were on 25 feet lines but the plane was way too fast on such short lines. Best line length seems to be 35 feet. I will add a video clip once I have shot some video of the Baby Ringmaster in flight. A very nimble plane indeed.
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