abufletcher

I guess my CI won't mind sharing some space with its "little brother!" It looks like another winner!

I've always thought of CAD as belonging to the "middle" of the design process. Ideally, a design starts in the head of the designer/builder and is hopefully grounded in lots of old-fashioned hands-on model construction, then this core concept gets "translated" into CAD drawings (if and where appropriate) that have as their sole purpose to allow the creation of a set of actual wood parts to be put back into the hands of the modelers.

abufletcher

Just one example of the changes...

abufletcher

I now have the NEW AND IMPROVED fuse parts and can get the build going again. The first thing I did was assemble the engine compartment parts (now for the third time). The most obvious change is a third ply flange on the right side. This makes assembling the parts easier and helps assure proper alignment. It also provides support for the contour of the right side wall.

The new flange initially created a new problem: It blocked the needle valve. So in thinking of how I'd solve that problem, I reversed the RCV's carb. This would put the needle valve on top, which might be convenient and the extension wouldn't be too obvious (next to the dummy). But then the throttle arm is on the bottom, which could make the linkage more difficult (though the tank area). Scale building is all about choices and compromises.

Anyway, it's nice to be underway again.

abufletcher

This shows the carb with the needle facing downwards. It's awfully close to the muffler.

CTDavies

Needle facing downwards is how I would do it, if it were mine. There will be a lot happening on the top side with the dummy engine and all. You could fix the silencer to the airframe with a bracket and use a bendy pipe as a manifold. See if it can be fixed perpendicular to the line of flight under the tank bay with the exhaust on the other side. Chris

abufletcher

Well, there are things to work out either way, so I guess I'll go ahead with the needle-down orientation as that easiest for the throttle servo linkage. I drilled a 1.5cm hole through the right side flange for the needle valve. I can't get the engine in without first removing the needle valve.

jeffski

Hi Abu,have you thought of useing a remote n/v ? or flip the engine over, it may makeit possible tomake a working exhaust ?as for the throttle link try something like i did on my cap 232.
On a differant note,try looking for r/c ww1 combat&crash on u-tube,you may find it amusing !

abufletcher

Chris and I decided on the right side mounting so that we'd have both one completely clean side view and also the ability to have a full dummy engine. I have thought about trying to route the exhaust through a working scale manifold. We'll see.

abufletcher

I've almost got the new fuse "boat" up to the same stage are the previous version. The new version is approximately 100g lighter...which takes 20% off the old weight. But more importantly there are a number of significant refinements to the design.

abufletcher

Here are the two "boats" side by side and a list of the differences.

1. Most obviously, there are now lightening holes in the side ply doublers.
2. The shape of the doublers have been altered to full enclose the sides of the tank area.
3. A "bracket" for holding the slotted beam for the forward cabane struts has been added.
4. The front end of the doubler has been lengthened so that they now glue onto the sides of F1.
5. The size of F1 as been altered to accommodate the side doublers.
6. A new ply flange supports the right side curve of the ply doubler.
7. The beams for the throttle servo have been lowered slightly.
8. Several of the parts are now made of lite ply.
9. There are lightening holes in the lite ply floor boards.
10. The cutouts in the two "keels" have been enlarged to allow the servos to be installed and removed from below.
11. The "jack" parts of the keels have been broadened for strength.
12. There's now a cutout in the dashboard support piece for the upper longerons.

It's still amazing how straight this all builds just because of the way the parts interlock. And all the parts fit with micro-millimeter precision. Most of the parts have been glued together with CA behind the tank area. From the tank wall forward, I've used epoxy.

***Note: Chris advised me to fit the ply doublers BEFORE adding the brass tubes. The holes for the tubes will need to be fine-tuned a bit with a circular file.

Frank Sopwith

Hey Don,

what is that on your face? Oh I see it's a smile

Frank

(took some effort huh? to make you happy)

abufletcher

It's my job to be unhappy with prototype parts!

The next task was to cut away the right side doubler to accommodate the cylinder head (as well as allow installation and repair). Luckily with the new ply flange, doing this is no problem. To get the engine in, I need to remove the needle valve, and the muffler (but not the manifold), I know it's a bit ugly looking, but it does give us an absolutely pristine left-side view, including a full dummy engine. And I think I'll be able to camouflage the right side a bit to look like "working bits." And a removable "top skin" can be cut to a closer fit.

The second photo shows the clearance past the muffler for a needle valve extension.

abufletcher

1. The slotted beam for the forward cabane strut needed to be slimmed down in the middle so that the 90z SLEC tank can be inserted and (later) removed.

2. The side "rail" stabilizes the formers and ensures they'll all be straight.

3. Looks like a clear path from the throttle arm to the throttle servo.

abufletcher

Silly (but necessary) question: How do SLEC tanks work? [sm=72_72.gif] Chris was kind enough to send me one of the 9oz. SLEC tanks that he recommends for the CI and they do look like very good tanks.

But I don't quite understand how to do the plumbing. There's a metal nipple that screws into the center of the tank face. This has a tube and clunk attached and is obviously the fuel line. Then on top there are two OPEN plastic nipples. I would assume one could be used as a pressure line to the muffler. But what about the other? Then on the side there are two more nipples, which are current blocked but that could be opened up.

My preference so far as been for a standard 3-line setup (one fuel line to the carb, one pressure line to the muffler, and one fill-unfill line). Normally, I'd use a second clunk on the fill line.

****

Note to self: Do a test run of the RCV91cd with the 9oz tank to see what kind of run-times I can expect.

Mode One

Yes, late, but, I am watching. Chris, did you get my PMs?

abufletcher

1. The ply (0.4mm) tank area wall over liteply frame. This whole area will receive a coat of fuel-proofing.

2. The parts for the rear fuselage. Because this is a completely different style of construction from anything I've ever seen, it's a bit confusing. Also a bit confusing is that the plans don't (???) include a view over which one can directly build. Instead the positions for the formers need to be marked from the side view. Building over the bottom view could lead to errors.

I'll need to mull this all over for a day or two before I start gluing parts together. And I'll need to review any mods that Thomas might have made here.

jeffski

The two to holes are just the normal vents,fill/pressure &overflow,to empty the tank you have to invert or stand the plane on it's nose,the two blocked nipples are there so you can link them with f/tube so that it gives you a 'fuel gauge'.I no longer use these tanks as I found the fuel pickup kinked or would fold forward toeasily and the tube on the vent/fill would pop off if not fitted dry,any hint of fuel would come off ,more so if the tube had to make a 90 turn to clear a bulkhead

Mein Duff

Don,
Really enjoying your build and meticulous work so far... just wondering what you will be using for fuel proofing on the forward section of your CI?
Keep up the good work and keep us clued in..

abufletcher

In Japan everyone uses a two part paint called "engine uretan." Looks and smells like a two part epoxy to me.

abufletcher

I don't like the idea of having to invert the model or stand it on its head to empty the tank. Chris suggested that I could block off one of the top nipples and open up the bottom side nipple as a fill line. As far as the fuel line getting kinked, yes, I was concerned about this since they use a thin walled tube (so that it slips easily through the center hole. I think I'll replace that with heavier tubing.

Anyone else had any problems with the SLEC tanks?

GianFrancesco

Hi Don
in my Albatros I have the same "yellow" SLEC tank as you and (I keep my fingers crossed....) without problems; I fill and empty the tank via a (concealed) Dubro Kwick-Fill Fueling Valve.

abufletcher

I'm ashamed to admit that I don't understand how the Dubro Kwick-fill would work or how the plumbing would go. [sm=52_52.gif]

Mein Duff

I have used the Dubro Tank and the external click insert /coupling system for filling and emptying for over 15 years without a hitch...I would highly recommend this set-up.
The external fill coupler is easily hidden inside the fuse, all you need is about a 1/4 inch for access hole or a hatch for access to the coupler to insert your Dubro male tube insert.

GianFrancesco

I was a bit embarassed by your comment and I checked the model in doubt to have written a nonsense.... but it works!
There are two lines from the Kwik-Fill: one to the clunk line of the tank; the other to the carb inlet nipple; normally the tank is connected to the carb; when the probe is inserted it opens the line to the tank and you can fill or empty the tank.
In the tank I used only one of the open nipples to vent it; the second one is closed.
I too have changed the silicon tube with another more heavier.

geezeraviation

My Feedback: (3)

I use Graupner tanks pretty exclusively. Same old fashioned three hole rubber stopper but the shape of the tanks (9oz,17oz,24oz) just fits most fuel tank compartments better. A 9 oz measures 3"wide 3 1/16 tall and 4 1/16 long and the stopper is inset about 1/2 inch at the front. I usually replace the plastic/nylon cap and inside part with 1/8" aluminum sheet. Works for me.
Doc