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Jul 13, 2019, 04:42 PM
It's all about scale models!
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Build Log

CY Models ME-163 Komet, 60" Span


Let me begin by first stating this is actually an ARF model, which could be built fairly simply and be ready to fly in just a few days. However, I will be rebuilding many aspects of the model, and will be repainting and detailing to a higher level. I'm of the opinion most of those on the "electric warbirds" forum aren't really that interested in rebuilds such as this.

I'm approaching this project sort of like a friend finished the wings and had a fiberglass fuselage and lost interest, and sold everything to me.

One reason I look at the electric planes for sale classifieds is that it introduces me to models of which I was unaware, usually out of production stuff that I then try to hunt down. However, in this case I discovered that the "new" (to me) model, a 60" span ME-163 Komet, was available here:

https://www.texasrcplanes.com/me163.html

I also found two threads on this model, dating back to 2009 and 2011:

https://www.rcgroups.com/forums/show...-Models-ME-163

https://www.rcgroups.com/forums/show...%28Kraft-Ei%29

I read through both threads, and found that, while a challenge, most thought this a very good flying model. I figured it had "good bones" (like they say about fix-er-up houses), and plunked down my $299.95, plus $50 for two-day shipping.

I've had a thing for the ME-163 Komet since I was a kid. As a teenager, I mostly flew competition rubber scale, and wished there was some way to make a Komet. Following a 30-year absence from model planes, I got back in almost 4 years ago, and with the new technologies in electric RC, I am hooked -- and flying planes I could only have dreamed of 35 years ago. Case in point, the HobbyKing/Durafly Komet, 950mm span. I've worn out a couple (around when I was really not up to this model) and have two still flying that I repainted. It's a great foamie in my opinion with almost nothing wrong, assuming you set it up right. But it's, um, small... Most of my models are 48-60" span now.

The CY Komet arrived double boxed with no damage whatsoever. The fuselage is fiberglass, while the wings are built up balsa with Oracover finish. There's a fiberglass cowl, vacuformed canopy, aluminum spar, and a few bags of hardware. The quality of what you get is actually very nice -- the only problem, if you care, is that it's shiny green on top and silver on the bottom, with a few airbrushed mottled spots on the silver rudder. The best you can call it is semi-scale. But the outlines aren't too bad, and on the above threads I'd already seen the improvements made by others. I think there's real potential here.

So let's get started!

After unboxing, it took seconds to insert the aluminum spar and press-fit the wing panels -- gee, it practically looked finished. If this is OK for you, just add motor, esc, rx, and three servos, and you're ready to go.

I started by trimming out the canopy. I tested some of the plastic in the margins. I don't know if this is old stock or what, but it was very brittle, and prone to cracking out from the cut line. So I proceeded very carefully on cutting the final edge, with X-acto, and sometimes scissors after scoring. I'm happy to say that I managed to do this without any cracks! The furnished wooded frame was too large in the back and had to be sanded until the canopy could be flush with the fiberglass. This frame will be modified quite a bit as I add cockpit detailing.
Last edited by MrSmoothie; Aug 06, 2019 at 07:45 AM.
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Jul 13, 2019, 04:58 PM
It's all about scale models!
MrSmoothie's Avatar
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Intentions


I like to outline some of my thoughts at the start of a rebuild and see later how well I achieved the goals.

This will be an electric powered model. After researching what others had done, I settled on a Rimfire 5055 - 650kv motor and a Castle Talon 90 ESC. Prop will be 12 or 13" APC, with 6s 5000 mAh lipo.

The model is intended to use a fixed gear (provided). That won't do, of course. Several guys have made theirs "drop away" like the real Komet, and that's almost certainly how I'll modify mine, although I may do it a little differently. The HK version has a very clever servo activated magnet release which works very well, once you trim the plastic a bit and make sure no sand is in there...

My biggest complaint about the model as provided is that the wing panels are not fully sheeted but have large open areas with capped ribs. This just ain't right on a Rocket Fighter! I hope to change this situation and have an idea in mind on how to go about it. I will keep the panels removable but intend to have tabs and retaining screws, much as the typical foamie has. With wing panels removed, this plane fits very easily into a trunk -- leaving my backseat available for larger things like a 90mm F-22 Raptor or 1600mm F4U-1 Corsair.

I'm not into "full cockpits" as I view them as a lot of work that you can't really see in the end. However, I like anything visible above (and slightly below) the "sill" so gunsight, armored glass, instrument panel, seat top, headrest -- and of course, a decent 1/6 scale pilot, which I will be 3D printing.

A complete repaint is in store, and I will be doing my own graphics (in CorelDraw) to be output by Callie.

The model uses a spinner with the prop. This creates a very inaccurate profile. I intend to modify the fiberglass cowl at the front with a 3D printed part with the prop in front of that, much as the tiny electric generator prop was situated on the real craft.
Jul 14, 2019, 06:11 AM
EB-66C Team Member
J Morgan's Avatar
This will be very interesting to follow along. I've scratch built maybe half a dozen Komets at various sizes all the way up to 1/4 scale. They all fly great, just a great planform for an aircraft. I'll be watching how you approach the dolly as I have my large one set up for bungee but really need to build a dolly for it.
It weighs 13 lbs AUW and goes off the bungee like a kite!

J
Jul 16, 2019, 03:54 AM
Registered User
I am just finishing off my build. I have converted it to electric, put a sort of semi scale cockpit in, fibreglassed the wings and repainted the model as I wasn't keen on how it arrived!

I have also fin mounted a slim servo as I wast happy with the factory set up of that long wire and weak looking joint.

I used my girlfriends vinyl cutter and cut out the paint masks for the insignia, for a first go I am happy.

Hoping to fly it friday as long as I get it balanced and the weather plays nice.


Couple of not so great pics of the nearly finished model.
Jul 16, 2019, 08:05 PM
killickb
killickb's Avatar
Interesting kit Mr S, I don't know that one. I have Jim Kiels 82" version -- it can aviate as fast scale ship or a big old glider ! Originally glo powered now with E-Flite 90. Problem is prop clearance, 14" is all I can use so lots of pitch required. Use 5 or 6 cell 6000 packs. Dolly is auto drop off which means that sometimes it does and sometimes it doesn't. Don't know what control set up the CY has but mine is outboard ailerons and inboard elevators -- no elevons.

Will have to meet you when you get yours done.
Jul 17, 2019, 04:22 PM
It's all about scale models!
MrSmoothie's Avatar
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Quote:
fibreglassed the wings and repainted the model as I wasn't keen on how it arrived!
OK, so I'll spill the beans a little. I intend to cover the "open" portions of the wing with 1/64" ply. The sheets just arrived today. Paul, what did you put down before glassing? Did you sheet the entire wing or cut in individual fill panels from balsa, or what?

Quote:
I have also fin mounted a slim servo as I wast happy with the factory set up of that long wire and weak looking joint
I looked at this for quite a while yesterday. My preference was to mount a servo just ahead of the tail wheel horn, but the access was too small without going nuts. Seems to me that stress-wise, the tail wheel linkage should drive the rudder. I didn't want the servo to drive the rudder and then by extension, the tail wheel. I also started to think about the 17gm servo in the tail, and the, what, 80 gm I'd need to compensate in the nose? Going by my HK Komets, CG is easy to attain with the lipo quite centrally located, so maybe that wasn't a valid concern.

So as it stands, I will have the servo up front with a pushrod, although it won't be the dowel the kit came with.

I know that I will only be using the rudder for takeoffs -- unlikely to touch it once airborne.

Paul, what size (gm) servo did you decide on for the rudder?

I got 17gm Freewing metal gear servos all around -- what Freewing puts in their largest EDFs.
Jul 17, 2019, 04:23 PM
It's all about scale models!
MrSmoothie's Avatar
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Quote:
Interesting kit Mr S, I don't know that one. I have Jim Kiels 82" version
Ha! Barry, I should have known you'd have one. Check out my updates on my father's Black Horse Lysander over on HobbySquawk -- you'll like it.
Jul 18, 2019, 06:09 PM
It's all about scale models!
MrSmoothie's Avatar
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Rudder


This managed to take longer than it looks. First, I determined that the rudder wasn't correct in profile, so I added soft balsa, reshaped, and capped with basswood for a bit of strength against nicks, etc.

I spent a lot of time looking at the linkage for the tail wheel and rudder. I was hoping I could fit a servo down where the control horn is, but too tight. I then thought about putting the servo in the vertical stabilizer as others have done. But I don't like the idea of driving the rudder to then drive, by extension, the tail wheel. So I ended up using the provided control horn.

However, I was not about to use the big dowel provided for a linkage. I used a CF tube (actually a salvaged arrow given to me) and added wires to both end -- short right angle bend to fit a drilled hole, then a section of dowel, halved lengthwise, epoxied in behind the wire. Seems very sturdy and light.

I made a mount for the Freewing 17g metal gear servo from plywood and epoxied in place off to the side of the interior.

The kit provides two giant Robart-style hinges. The pre-drilled holes were a little off center, and needed to be enlarged for the ends closest to the pivots. But in the end, these will work really well, I think. I'm not gluing them in quite yet.

I also cut out part of the battery tray -- I needed access to the area where the landing dolly hardware will eventually go (for my drop-off design). The tray (or one like it) will be easy enough to add back in later.
Last edited by MrSmoothie; Jul 19, 2019 at 06:43 AM.
Jul 18, 2019, 06:13 PM
It's all about scale models!
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Power System


My power system arrived today. One of my flying buddies has been bugging me to use better components. He's costing me a lot of money.

The Rimfire is 5055, and 650kv. The size is the same as the motor in my big 1600mm Flightline Corsair, but that motor is around half the kv, as it turns a huge 17" three bladed prop. Here, I'll be using an APC 12 or 13x8E two blade prop. Should be pretty zippy!

I may get going on the motor mount next, while I continue to plan out how to do the wheel dolly. Many of the previous builds just used the three provided mounting bolts and drilled out the mounts. I'm going to make a much beefier two-pin system (or at least that's the present plan). There was a terrific large Komet featured in Model Airplane News a couple of years ago (you can find the article online) and that plane used a two pin dolly (and was much larger and heavier).
Jul 18, 2019, 06:21 PM
It's all about scale models!
MrSmoothie's Avatar
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Here's the Model Airlplane News article which has had me wanting a larger Komet ever since. I thought this was a terrific job. I agree with the decision to put the prop in front of the cowl (and not try to use a spinner. Note also the use of a two-pin dolly, which simply drops away.

https://www.modelairplanenews.com/16...t-performance/
Jul 19, 2019, 10:44 AM
It's all about scale models!
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Motor Installation


I spent about three hours this morning installing the motor, and as far as I can tell, I didn't screw anything up! It's nice to not have to go back and correct your own mistakes.

I'm sure most reading this won't see anything new. However, that I know how to do this is the result of reading through similar build logs on RCG, so maybe it will be informative to somebody relatively new to the hobby, or like me, coming back to a radically different hobby after a 30 year layoff!

Before I go further, people ask me how I make such nice ply boxes or retract mounts -- and the answer is that it's not me so much as the tool -- some years ago I invested in a pricey mini table saw, made in Japan, from MicroMark. If you already have one, I need say no more. If you don't, you'd probably think I was crazy for spending hundreds on a little saw. But it's been worth every penny, er, dollar. I use it all the time. The masonite, wood and aluminum contraption is a sliding affair to push wood through the blade while keeping my fingers way off to the side. MicroMark sells one, but I made this one.

From reading previous threads, it seems there's not really a need to add down or side thrust (although some may be built into the firewall), so I went with a symmetrical box of ply, which I took pains to center. The box depth was designed so that the the front of the motor (and not the aluminum prop hub base) was even with the front of the cowl. My intent is to design a 3D part which will go on front of the cowl, and taper down to the aluminum hub (and not use a spinner). I beveled the sharp edges of the prop hub base on my lathe with a file to provide a bit more clearance which may be necessary later.

As you will see, the front corners of the ply box needed to be sanded to a taper to allow for clearance inside the cowl. Speaking of the cowl, something like 1/4 inch of the back edge needs to be trimmed off to make a nice flush fit, which I carefully did. I've seen a few builds where this wasn't done and it really makes a mess of the fuselage profile.

I don't have much experience adhering to fiberglass, so here's what I did -- I roughed up the areas where the ply box would attach with 60 grit, and cleaned. I marked off four places in the firewall for screws which would go into the box from the inside of the fuselage, and drilled. Then the box was attached with 5 minute epoxy. Then four #4 x 3/4" hex socket head sheet metal screws were put into the box from the inside. They were very tight, going through the thick firewall into 1/4" ply --I know they will ad a good measure of strength here. The epoxy may have been enough, but I have seen motors come off in flight for various reasons -- and it never ends well!
Last edited by MrSmoothie; Jul 19, 2019 at 10:52 AM.
Jul 19, 2019, 06:24 PM
It's all about scale models!
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Dolly Progress


We can probably call this chapter "overkill". In my defense, watching videos of the stock gear setup, with the plane wobbling back and forth, or if droppable, needing big foam blocks between gear and fuselage, made me think stronger would be better. On one hand, I'm adding weight to the fuselage. On the other hand, the dolly won't be going for the ride.

I had some machined brass parts in a bin from my days doing brass musical instrument repair. They looked like bushings, and I also found some heavy wall brass tubing into which they slid perfectly. It seemed I had found my two "pins". Using my lathe (by hand, power off) I threaded each of the bushings to accept a 1/4 x 28 hex socket bolt. The dolly base was cut from 1" x 1/8" aluminum bar stock and holes drilled. To mount the kit's gear to the base, I drilled and then threaded for M3.

The pictures tell the story -- I doubled up on the kit's formers around the gear mount area, and then epoxied the heavy brass tubes, and ply supports to the sides and then to "seal" in. I'm thinking it's 3 or 4 times as sturdy as what was provided.

I took great care to make alignment lines and when gluing in the rear tube, I stuck the bushings in the bottom to see if things looked aligned -- and moved teh rear tube a little off of my line. I should have trusted my line -- I actually moved it off kilter. But it seems to sit straight.

I was of course concerned that any misalignment of the two pins would cause resistance and prevent the dolly from dropping. I found by keeping the 1/4x28 bolts just a little loose, or even just the rear one, that was no problem and fuselage doesn't wobble. My "ace up the sleeve" are two compression springs which fit tightly into the bushing. Turned-down dowels were inserted into the fuselage tubes from the top, causing the springs to be compressed with the dolly in place and fuselage on the wheels. It appears that between the weight of the dolly and the springs, the dolly drops every time. Of course, there's no sand in there yet (a constant, flying in Florida) -- so this may not be a done deal. I know that "failure to drop" can cause some real problems, so I want to make this as reliable as I can.

My tentative plan is to fly first with this wide track kit landing gear, so modified to drop. If everything works well, I'd like to keep the part that I made, but replace the gear with something narrower and closer to how the real dolly looked -- but probably not as narrow.
Jul 22, 2019, 03:04 PM
Registered User
Sorry for the slow reply, your build is coming along well and your motor box is certainly neat :-)

I am interested in your dolly mechanism because once mine has flown I will be modifying the dolly to be droppable.

For the wings I removed the spar caps and then cut in fill parts in balsa, slightly thicker than the wing sheet so that way it gave me some material to remove with sand paper and get a nice profile on the wing without the need to get too much filler out.

For the rudder servo I used a TGY A55H, probably a bit overkill but I had it in stock for another project that isn't going ahead now.

I am hoping to maiden mine on Wednesday with the CG set at 140mm and 5mm reflex. Fingers crossed!
Jul 23, 2019, 10:33 AM
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Dolly Part 2


OK, so I'm from the school of "can't leave well enough alone." Literally, the day after I finished the dolly modifications, I was at a flying buddy's shop picking up something and he had a small box of junk parts out. "What are these?", I ask, referring to filled nylon mounts with brass inserts. I was told back when planes could have retracts but didn't come with them, these were the fixed gear mounts. I'm standing there thinking, gee, I sure wish I'd had these a day ago. Then I look in the same box and see steel rods with wider, threaded ends and nuts. I pick one up and it's a perfect fit to the brass insert. They are wheel axles.

I take home a pair of each and decide this is a much more elegant solution. Of course, I've made a "brick s**t house" of an installation already and wonder how easily that will all come out. Well, the answer was not easily at all. But I took the risk of screwing things up, and eventually I pried it all out and only damaged the fuselage fiberglass a little (repaired).

Another long afternoon and the new dolly setup was done. I still think I'll be able to use the same compression springs over the steel rods to help ensure the dolly popping off. Just need to anchor them at the base of the dolly.

After adding a bit of vertical support, a 1/8" ply shelf was added for the ESC, Rx, and Lipo, extending all the way back to the wing spar. From what I've read, there's a good chance the lipo will go against the spar.
Jul 23, 2019, 10:42 AM
It's all about scale models!
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Nose cowl ring and rudder


Part of my plan was to design a 3D part to extend the front of the cowl a bit and not use the spinner. I made the design in Tinkercad.com and after one mistake and a revision, got what I was looking for. This was primed with SEM high build primer, and then epoxied to the cowl. I drilled 1/16" holds in each part around the periphery to help ensure the epoxy would hold. A bit of filling and priming and it's ready to go. The fit was just what I had wanted around the front of the motor. I got a special nut from TruTurn that is the same shape as that found on the full size generator prop (although much larger, of course).

Of course, I ordered the wrong size prop nut -- I thought 8 x 1mm -- turns out it's 5/16" x 24. I never would have guessed. New one on the way.

Small hardwood blocks were cut, shaped, and expoxied 120 degrees apart. The cowl attaches with Dubron #4 button hex head screws. I hate using little phillips head screws. I always manage to lose at least one, or slip off the head and scratch the paint. Hex heads are a bit of a pain in that you have to go through your tools to find the right size, but worth it. I do find it more of a pain that Dubro persists in using SAE and not metric. It's getting hard to find SAE hex screwdrivers (that don't have ball heads).

I knew I had to do something with the rudder which I extended to a better outline. I was hesitant to remove the Oracover for fear of making a mess of things, but then saw on Youtube how you could use a heat gun to get the stuff off -- this worked and I had a bare balsa rudder in short order. I then put some Tower iron on covering that my buddy gave me. First iron-on covering I've done in about 40 years! I was happy with the result.

This will be painted. To that end, I did a test of flat gray Krylon Fusion on the same material and was happy to find that it adheres beautifully, passing the scratch off test. Way better than the pain on foamies, that's for sure!

I was all done with the rudder linkage, so went to fit the provided fiberglass panel -- which didn't fit at all (not curved enough). I formed some sheet styrene to the right curve, and cut to fit. I backed up the fiberglass with strips of basswood so there'd be something to screw into, and used 6 small #2 button hex head screws. These look far less conspicuous after painting, as I've used them on other projects.
Last edited by MrSmoothie; Jul 23, 2019 at 05:20 PM.


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