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Nov 14, 2018, 08:10 AM
Themadartist
Thread OP
Build Log

Old Meets New - The Improved Rico


I have flown RC on and off for nearly 30 years, and by far the models I have most enjoyed have been my Southern Sailplanes Rocochets, in various formats. My last Rico, a Slope version, came to grief at Larrikin Ridge on 15 June 2013. I know the date courtesy of the thread I started the next day to warn Frsky users about resting their Tx on a surface, such that the Range Check mode is silently activated !!!

https://www.rcgroups.com/forums/show...or-FrSky-users

Some commented that the wreck looked perfectly fixable, but there was an emotional connection to that airframe that meant I couldn't bear to fix it. It was one of those "never be the same" things. Maybe later we can get into that.

Anyway, in the lead-up to my (and my son Mat's) first Manilla Slope Fest, in response to my thread, Zipper offerred to make me a couple of fuselages from an old mould that he keeps in the shop. Needless to say, I took him up on the offer, and requested one of them to be "solid". I had anticipated making a sloper from this fuz, but time and tide caused me to lose a little interest.

So, a couple of years ago I started to "improve" the fuz, with the aim of turning it into a plug to then mould. The four modifications I have made or will make are:

1. I have ground down the shoulders from the original Eppler 205 (I think - maybe 374) to the slope-proven RG15 section,

2. I have shortened the canopy, and therefore the canopy opening, because such a large hole is no longer required (used to house up to five full-size servos and 'gadgets' for driving them) , greatly reducing the tendency for the fuz to break in front of the wing saddle,

3. I have added a rudder to the plug, so that the surface will now be moulded, and can be cut short top and bottom, if you know what I mean, and

4. The eventual fuselages coming out of the mould will be epoxy, glass cloth and carbon, as opposed to the gelcoat, polyester resin and chopped strand fuselages of old.

At this point I will close this first post, and acknowledge the awesome ship created by Ralph Learmont so many years ago. The fact that you still see Ricochets on slopes all around Aus is testament to their classic lines and performance in their day that was second-to-none.

I intend over the next week or so to add photos and descriptions of the process so far, and bring readers up to date with this build, which has come a long way in the last four or five weeks.

Hope you will read on and enjoy. Cheers, Steve.
Last edited by Guy97; May 07, 2019 at 09:15 AM.
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Nov 14, 2018, 10:14 AM
Registered User
chip.greely's Avatar
WOW! A Ricochet!

I've only seen one in tact Ricochet in the past 10yrs and that was hanging up in a Hobby Store, marked Not For Sale. Very cool plane.

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Nov 14, 2018, 09:13 PM
Themadartist
Thread OP

Changing the airfoil ...


Looking back over some old Ricochet advertising material I have confirmed that the root section of the Slope Ricochet was a "modified Eppler 205", which blended to a semi-symmetrical section on the tips.

Although the E205 is an accomplished profile, I thought it was appropriate to provide the new Rico with something a little sleeker. The RG15 profile came immediately to mind. Truth be told, if I were doing the exercise today, I would probably go with the HN1038, which has been used on frontside and DS models to great effect. There are always new sections coming out, and one could chase one's own tail forever that way. So, RG15 it is.

Fortunately for me, Zipper used a substantial amount of splooge in the wing shoulders, to the point that I only sanded through the skin in one spot. Cheers Glenn, I owe you one mate !!!

Having chosen the root section, there will of course be many discussions and opinions about the tip section to accompany it - and then there's the question of planform. All good fun for the future.
Last edited by Guy97; Nov 15, 2018 at 12:54 AM. Reason: Added a pic
Nov 15, 2018, 01:16 AM
Slow builder
_AL_'s Avatar
Very nice.

Al
Nov 15, 2018, 02:18 AM
Themadartist
Thread OP

Unforeseen synergy ...


Quote:
Originally Posted by _AL_
Very nice.

Al
Thanks Al, and welcome to the thread Chip.

Would you believe I went searching today to try and establish when the Ricochets first came on the scene. I found this old copy of the RCSD, and in the text it mentioned that the Unlimited Ricochet used a Girsberger RG-15 airfoil - I just couldn't believe it.

http://www.rcsoaring.com/rcsd/RCSD-1989-03.pdf

I'm left wondering what max thickness airfoil was used, that is, did they increase it to better match the shoulders, or was there a noticeable disconnect such as on the Bullet version.

If anyone knows, or better still has one of these, I'd love to know the answer.

Cheers, Steve.
Nov 16, 2018, 06:20 AM
Themadartist
Thread OP

A tale about tails ...


This post actually predates all other work I have done on the Rico. Even before I had crashed "Scooby Doo" or learned that Zipper could make me a fuz, I began my bagging career on a standard-size set of Ricochet tails.

Thanks to the patience and guidance of Mr Jeff Irvin, I have learned a considerable amount about composites construction in just a few short years. Well, these tails were the beginning of the story.

As you will see, they are nothing special, except to say that for a first-time effort, they came out looking pretty good and usable. Many of my club-mates at the time reported binning their first efforts. I don't know if that was actually true, or just aimed at encouraging me to keep going - either way, that was the result.

I found a little footage of the momentous occasions (one tail at a time - that mylar was a big investment) so I've put a short up on YouTube - as follows;

My First Rico Tails - "The Knuckle-head Manoeuvre" (3 min 57 sec)


Below there are a few pics of the building process, such as it was.

Cheers, Steve.
Last edited by Guy97; Dec 12, 2018 at 09:51 AM.
Nov 16, 2018, 07:11 PM
Just Toss It !!!
MATIN's Avatar
Oh yes!.....The wing planform !.....And the dihedral!

So if I wanted a Rico fuse to pick up next time at MSF, who do I order it from? Zipper?
Nov 16, 2018, 07:22 PM
by ZIPPER
ZIPPER's Avatar
I know a guy that might know a guy that can get you one.
Nov 16, 2018, 07:46 PM
Just Toss It !!!
MATIN's Avatar
Well lets do that!
Nov 17, 2018, 04:31 PM
by ZIPPER
ZIPPER's Avatar
I'll let him know.
Nov 17, 2018, 05:17 PM
Registered User
chip.greely's Avatar
Quote:
Originally Posted by ZIPPER
I know a guy that might know a guy that can get you one.
....or maybe two????
Nov 17, 2018, 11:57 PM
by ZIPPER
ZIPPER's Avatar
Okay
Nov 27, 2018, 08:23 AM
Themadartist
Thread OP

Now to do something about that canopy ...


The original Ricochets were cleverly designed to carry all of the radio gear in the fuselage, allowing all the various wing kits to simply "plug on" and fly, and the only adjustment that was necessary was balance point. Keep in mind this was in an era of full-size servos and receivers, which were very expensive at the time. To put that in perspective, I gave up flying RC in the late nineties because I lost the plane with my only JR receiver, and I couldn't afford to replace it !!!

Anyway, I digress. It is a shame I do not have better photos of the radio gear fit-out in my old Ricochet, because there was a lot going on under the hood - so to speak. Not only were there up to five full-size servos in the tray, there were ingenious devices designed by Ralph Learmont, to "drive" many of the functions. As an example, view the photo below that is rotated and cropped from the photo in Post #1 of my broken Slope Ricochet "Scooby Doo". At the top of the photo, circled in red, is the "shock-absorbing flap driver", which drove square brass tube torque rods that inserted into the root end of the flap. Also circled, is the bell-crank that drove the elevator via a square balsa pushrod that hugged the floor of the fuz.

The end result of all this "machinery" is that the canopy opening was, not to put too fine a point on it, absolutely huge. This, combined with the construction materials used, meant that many Ricochets suffered breaks at or about the leading edge area. This weakness was the main reason I reduced the canopy opening, to provide a more robust airframe. Also, because much of the radio gear is now wing-mounted, there is a vastly reduced need for such an opening.

After fiddling with different locations I eventually settled on a reduction of approximately one third of the original, all taken from the rear of the opening. I carefully cut the original canopy so I could use the offcut to add to the fuz, and still use the remainder to mould the new canopy.

One of the fiddliest jobs I ever undertake is producing the internal "lip" onto which the canopy seats. From the photos you will see that I did this task in a few steps, eventually seating the new dummy canopy straight onto the fuz and splooging it all into a seamless shape. Though not perfect, I am quite happy with the results.

One important consideration was to not ruin the original look of the fuz. I could easily almost halve again the new canopy and have ample space for fit-out, but keeping the original look and feel was important. I'll be happy to hear your thoughts about whether I got this right, albeit now a little late to do anything about it.

In the next couple of installments I will describe the process I have used in preparing the plug, and moulding the fuselage, and then this log will be about up-to-date. At this time I have just put gelcoat down on the second mould side.

I have included a pic of the new canopy mould, but I don't think it needs any more than that - quite straightforward.

See you next time, Steve.
Nov 29, 2018, 06:45 AM
Themadartist
Thread OP

Finishing the plug ...


I typed the title to this post, then had a bit of a chuckle - it seems that until the last of the gelcoat is down, you're never finished preparing the plug. You always seem to find or notice some little detail that draws you in to "I'll just touch that up and she'll be ready" syndrome. Anyway, here's a bit of a rundown on the process I went through.

The first things I did to the plug were slimming down the shoulders to take the RG-15 airfoil, and reducing the size of the canopy opening, as described previously. The "only other" things to do really were to attach a rudder, and fill in all the pinholes in the bare glass finish.

The original Ricochets had a full-height, foam-core balsa sandwiched rudder that was attached with pin hinged after the finpost was installed. This allowed the builder to easily access the rear of the airframe to install the elevator bellcrank. I will adopt the current process that I use on my Lunatic builds. Basically I now cut out the rudder from the fully-moulded rear end, install the bellcrank, then the fin-post, and lastly I mount the rudder with a silicone hinge.

Thus, whilst having the same side-on profile as any Ricochet, the rudder will stop short top and bottom, giving it some protection.

I dug through my box of templates and found some old actual profile templates in one of the NACA , symmetrical foils. I chose a couple whose last 45% or so met the chords I was looking for. I then just cut a full-height rudder from a scrap of blue foam, made a couple of make-shift "mylars" from thick plastic (which I painted with primer-filler) and laid up the rudder in a normal vac-bagged manner. I used a veil layer of about 107gsm glass, a reinforcing layer of 165gsm glass, and added a 12K carbon tow in the TE.

Once the rudder had cured, and was trimmed I made a number of cut-out to accept the ends of a few "pencil-style" paint brush handles. Between these I added foam strips so that the fin and rudder had better area on which to glue. Then it was just a matter of a solid splooge mix and tape and clamp till it was also cured.

Of course, these things rarely line up perfectly, but it was a good enough fit to need minimal bog to mate the surfaces. The only addition, in hindsight, would have been to fill the fin with expanding foam before mounting the rudder - this would have minimised movement during the sanding process.

Then it was on to the pinholes. I mixed up a slightly runny mix of some plaster filler, and basically rubbed it all over the fuz with my hands. As this is a water-based product it must be dry sanded, and it must then be covered with a suitable primer / filler. After most of the pinholes had been taken care of, I went on to the usual cycles of spray putty, mist coats, sanding (repeat, repeat, repeat) until it was ready for a top coat/sand cycle.

Once I had a couple of topcoats on, and sanded down to 2000 grit, I thought "that's it for the plug" - but I was wrong. Next post will describe the preparation for moulding ... and why I was wrong !!!

Till then happy building and/or flying, Steve.
Dec 01, 2018, 11:30 PM
Themadartist
Thread OP

Into the parting plane ...


I've added much of the description of this process to the relevant photos, to make sure I covered everything I wanted.

A couple of general comments. I typically use 42 x 19 dressed pine for my fences. It's pretty cheap, well finished, and very easy to work with. I can be planed, sanded, sliced, PU's, hot-glued and screwed, all with relative ease. In this cas, however, the fuz plug at its widest is about 95mm, so that put an end to pine.

Shane (PlayinInThePark) had generously given me some offcuts of PVC in different sizes and configurations. The main fences you see in the photos are a sort of PVC sandwich board - I don't know how else to describe them - which are 50mm x 20mm - PERFECT.

My intention was to somehow reuse the fences for the second side of the mould - and I will describe that in detail in a subsequent post. Suffice to say that a little forethought and planning allowed this to happen.

I still used the 42 x 19 pine for the braces / stiffeners that go below the parting plane to keep it true.

Typically, when doing the talc splooge, I have in the past used a split parting plane. Basically you separate the top and bottom 'halves' by cutting straight out from the nose tip, and somewhere along the rudder. This has two advantages.

One, when the splooge is cured it tends to trap the plug, making it difficult or impossible to remove without trimming the splooge. A split plane allows easy removal.

Secondly, when finally fitting the plug in the plane, ready to mould, the two halves can be nudged up to the plug, reducing the small gap that always seems to occur.

I honestly don't know why I didn't use a split plane on this project, but I didn't, and had to work around the issues it caused.

Lastly, even though I had waxed and PVA'd the plug, and set it on the cradles using transfer adhesive tape, I was so paranoid about the fin / rudder moving, that I made a quick decision that turned to disaster. I got out the old glue gun and ran a bead of hot-glue under the parting plane, against the LE of the fin, base of the fuz, and TE of the rudder.

When it came time to remove the fuz plug so I could rasp and sand the talc splooge, I began to lose 'chunks' of my plug to the hot-glue. You can imaging how that went down. AAAARRRRRRRGGGGGHHHHHHH !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

So, after (again, foolishly) believing I had finished with the plug, it was back to square one. More on this, and making the moulds, next time.

Cheers, Steve.
Last edited by Guy97; Dec 02, 2018 at 12:50 AM.


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