FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

A couple years ago, I got a chance to buy an OS Pegasus 3.2 cu in flat 4 cylinder, 4 stroke engine. I got a really good deal on it, and it had never been started. I figured I'd find some plane whose scale design allowed the beautiful cylinders to poke thru the cowl really easily. So, I started my search.....and surprisingly nothing I really liked was available as an ARF. I don't have time to build a kit right now. The plane would need to weight between 18 and 25 lbs approximately. So, no Cub, especially, fit the bill. A 1/3 scale Fly Baby works, and the cylinders do show on that one. But no ARF.

There are some Cubs advertised to fit the 50cc gas engine class, but they are just 1/3 scale CLIPPED WING Cubs. The gorgeous Pegasus is completely swallowed up by the huge cowl. On Ebay, a guy sells plans for a 120" Cub that would work, but his plans I think are just scaled from some other size. So all the lumber would be non standard thicknesses. One would need to rip one's own lumber, or redraw the plans to resize the sticks. No time for that. So, I tabled the engine and forgot about it. Until just recently, that is.

I happened to Google 50cc Cub last December, and a reference came up from World Models. Then, I tracked down a magazine ad in a recent Model Aviation that advertised the same thing. Turns out, Fai Chen of Airborne Models in California has been working with World to design a true 50cc Piper Cub with a 118" wingspan. At the time I first talked to him in December, the kits were not available, but he was expecting them in January. So, we kept in contact and the container from China finally arrived on Jan 8th. I asked Fai to measure the cowl width, because I wanted to make sure the Pegasus cylinders would poke thru in a scale manner. Once I verified that, I placed my order. The Fedex tracking number promises my 50cc Cub ARF will arrive on Jan 22nd, and I couldn't be more excited to finally find a home for that Pegasus.

Fai has a few more 50cc Cubs, but I don't think they'll last long. He also has the same Cub kit in the Brazilian Paulistinha colors. I'm seriously thinking of stripping the covering and doing this thing up as a military L4.

So, I plan to post first impression pics of the kit when it arrives, and build progress pictures as it comes together. If anyone else buys this rare size Cub, your participation here would be awesome, to compare notes. I'll post some pictures from the manual, and of the Pegasus engine.

If you're interested in buying one, email Fai Chen at [email protected].

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

FEDEX emailed me the Cub kit is scheduled for delivery today. I'll post pictures of first impressions later tonight 1-22-2013. One feature I notice is it has a 2nd cowl provided which is clear. This is designed to help locate where holes need to be cut.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

I took a set of Nelitz plans 140" and reduced down to 120" by going to my local copy shop,there is no redrawing,my new cub will be all alum and stainless tubeing and putting a 48cc twin 2 stroke the heads will stick out just enough for good cooling.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

checking this out, the Pegasus looks cool, I would grab one anytime.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

I received the 50cc Piper Cub from Airborne Models last night from Fedex. The box arrived in perfect condition and there was no shipping damage at all. Set the box aside and ate dinner, etc. Prolonging the pleasant anticipation. I've attached some photos here for all to see. I'll go in to more detail tonight, but I'll say that my first impression is this ARF is AMAZING. The visual quality is really really good. Have to wait to assemble this monster to judge the fit. But, in general, I was very impressed. For the money, you can't do any better. The hardware is outstanding.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Here's the rest of the pics of the new kit.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Hey Pull Up, does it have the fillet where the tail fin transitions
to the fuselage. I would hate to see that beautiful engine sticking
out of the cowl only to see a chunk of wood back there.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Thanks Nitro. Yeah, it's a dream engine (OS Pegasus 3.2), and I got lucky when I found it at the height of the recession. I am SERIOUSLY considering converting it to gasoline. I've done that a few times before with Saito 4 strokes. I have a Great Planes Stearman with a gasser 120 (conversion) and it's so reliable that I am amazed i've not had to take it apart for any maintenance. So that's encouraging me to try this one. I'd convert it in such a way as to switch it back to nitro if things didn't work out as well as the Saito.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

That project sounds really nice Dadragon. How are you attaching the aluminum tubes? heliarc? Solder? Stainless, of course, can be brazed. And, since you're switching to tubing anyway, the dimensional discrepancy on the lumber from shrinking the plans is no issue for you. Besides, I wanted an ARF. You have some pictures of the Cub you're doing?

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

I'm not sure! That's a great question. I didn't see a fillet piece that goes between the horizontal and vertical stabilizer, but that doesn't mean it's not there. I might have missed it. You could look in the manual, which I uploaded to this thread. Maybe it shows up there.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

OK, look at page 5 of the manual, at the bottom right side of the page. It shows there is a fillet. In the photo I uploaded, the vertical stabilizer isn't really seated in it's final position. My son is just holding it near it's final location. So, you see lots of unfinished wood that won't show when done.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Pull Up all will be TIG welded I am still building the fixture table so all the parts will be clamped to keep the heat pull to a minimum.lots of over center clamps and where i'll be mixing metals I'll be using a 2 part epoxy called METALWELD from SYSTEMS THREE.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Got busy in the last few days, but I finally got a chance to inspect the 50cc Cub kit in a little more detail. One amazing thing is the servo arms that are provided. They're molded plastic, round on the servo end. That end is designed to be bolted to the round servo arm that comes on whatever servo you use. The other end actually has a little ball bearing molded into it. I assume that is to reduce any friction for the high loads the control surfaces place on the control system. I've never seen this in a kit before, and I am impressed.

The wings are supported by two aluminum spar tubes (not one big one). The wing halves plug onto these, and are held in place by a lever-operated quick disconnect system. I won't be wasting time at the field tighening wing bolts. Very clever. The horizontal stabilizer are also held by two tubular spars, and these also are removable. In fact, the entire aft section of the fuselage, including the entire empenage, is a separate piece. It would be interesting if this was also removeable for transport, but I don't know yet if that is the case. If it were, that would certainly enable transport for some folks with smaller vehicles. The comnpleted fuse is really long otherwise.

The landing gear is conventional welded music wire. It appears really well made, and I'm sure it will stand up to the load. It's not hinged, or scale at all. For a plane so large, that would have been nice. I'm sure the one provided will work just fine. I might modify it to be hinged if I get the urge.

There is a double fold out door system, with latches, already pre built. The outline is not quite scale, but certainly good enough. The doors operate very well, with a good fit.

One interesting feature is the cowl. There is a flight cowl made of fiberglass, and a second clear cowl designed to help with locating all the holes and cutouts typically needed for engine systems. I am installing a Pegasus 4 cylinder 55cc engine, so I'm thinking the cowl will have to be split horizontally into two pieces. Or, I'll made a long slot in the cowl and screw the filler piece back in behind the cylinders. In the latter case, the cowl would slide on, in a backwards motion. The screw the filler pieces in. I'll have to see if the engine lends itself to this approach.

More details later. Has anyone else contacted Airborne Models?

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Several years ago I assembled and flew World Models 1/3 scale Cub. You will find the fit and finish to be superb and flying characteistics delightful. From your photos it appears the parts design look just like the 1/3. The servo hardware is outstanding and wish other large scale manufacturers would take note.

Have fun.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Robart makes a very scale landing gear for 1/3 scale Cubs. I have a set on my Balsa USA 1/3 scale L-4 and they work very well. Balsa USA sells the gear on their website (part number 1017) for $185. Tower may have them as well... I also know of a source for a very scale tailwheel Cirrus Ventures, but you have to call him. If you want the phone number l'll dig it up.

Cheers!

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Thanks Galen, would love the phone number for the scale tailwheel. Probably that main gear won't work, as this Cub ARF is not 1/3 scale. It's more like 1/3.6.

Meanwhile, here's some more pictures and observations about this kit. I'll try to base the comments on what's visible in the pics.

There are two closeups of the main wing tube (spar) release levers. Though the hardware bags contain what looks like duplicate internal parts for the same mechanism. It's not clear to me if this is just an oversight, or if they have an additional use beyond what I can see.

3 various pics showing the OS Pegasus engine to show how much of the cylinders will be expected to protrude from the side of the cowl. I'm happy with what I see.

The main wheels are awesome...pneumatic but better and lighter than the typical Dubro's where the brass inflation valve always punches thru the tire, captured on the inside to rattle around. The caps don't say "Cub" unfortunately. Not sure why.

Pic#8 reveals the servo arms aren't the only moving parts with actual ball bearings molded in. The fitting by each control surface has them too. AWESOME! Also, the supplied clevises are really wide...enough to easily reach around their mating parts. Also, note that the servo trays, which are also the outer cover, are completely molded in tough plastic. No wood blocks to glue on. AWESOME! Also shown are the teardrop shaped nut and screw head covers, to give the model a more finished look. Very impressive attention to detail.

Pic#7 shows those little duplicate (?) parts for the wing spar retainers. Pic#6 shows a gas tank with a gasoline cork already supplied.. Pic #5 has a pilot guy...just another nice money-saving convenious from World Models. This kit is already well beyond average quality.

Pic#3 & 4 show the unusual separate empenage. It fits together perfectly. I'm contemplating leaving this removeable for transport. All that's really required are some appropriately located servo wire connectors, and some external nylon screws. I'll decide that later. Pic#1 & 2 show that nylon strings are placed to help the builder fish the servo wire extensions thru the wing ribs. Also shown is the wing root, where you can see the two spar tubes. They fit the fuselage perfectlyI've already tried it.

The only two things I can really find a little wrong is the cabin overhead window is rounded rather than square. Easily fixable, though I don't know why it wasn't done to scale to begin with. The other thing is the wing roots over the cabin aren't rounded inward like the real thing. Again, easily fixable. Just carve a couple balsa blocks and cover them with Cub Yellow Econokote, and cut out what's there to install your own PRIOR to installing the windshield, which will fit nicely over the whole affair either way.

This plane is so big I will finally use those huge 4000mah NMH batteries I bought a couple months ago. They are size C low self discharge, so they won't bleed down sitting around for the next flying day.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Sub.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

Sub.? What is that?

One mystery has been solved. Above, in pic#7, I'm showing those little black triangular pieces, and speculate that they're duplicate wing spar retention tabs. I thought that was the case because the wing itself already has some little levers. Well, it turns out those already-installed little levers are simply access cover releases. Inside, underneath those covers, one still must assemble the plastic items shown in pic#7. Those items are actually what locks the spars in place.

RE: FINALLY A TRUE 50cc PIPER CUB (Build Thread)
 

He "subscribed" to this thread... Personally I prefer to use the "Subscribe" button on the top of the page if I don't have anything to add to the topic at the time of subscription.

It's time for me to update this build, as a lot has happened recently on the 50cc Cub. It's been about a year and a half since I last looked at the Cub in the box, but I've really gotten going on this project. I'll explain the delay. I was building an F86 Saberjet turbine with a Kingtech K80 turbine. About 19lb static thrust. I finished that jet, and used it to get my turbine waiver. I've been flying it occasionally, and it's really a different experience. A monster, cookin' along at 150 mph. It almost disappears in the clouds on an overcast day. OK, on to the Cub. Somewhere, I got a bug to convert this thing to an L4 Grasshopper. Easy, right? hah! Well, the fuse is almost all done, and I've included some pictures of it. The paint is a bit delicate, as I've sprayed over the ultracote the kit came with. So, it became necessary to run less corrosive gasoline ignition rather than glow fuel, which would have destroyed the paint job. So, here is the L4 (cub) engine, an OS 4-stroke Pegasus 320 running on gasoline & electronic ignition. I'm really happy with the results. I'm using the stock carburetor, not a walbro. Here's a link to the video of it running. http://www.youtube.com/watch?v=FFc_VNBwGQQ

One thing wrong with the kit, the fuse width is too thin to be even close to scale. By my measurements, it's about 1 inch shy of what it should be with a 118" wingspan. It felt strange to pay so much for a kit, and then take a saw to it and cut up the fuse to make way for the major skylight windows in the L4 observation plane. One thing I spent a lot of time on is the air-to-ground radio for the back-seat operator.

And the pictures so far:

http://www.rcuniverse.com/forum/atta...mentid=2044949http://www.rcuniverse.com/forum/atta...mentid=2044950http://www.rcuniverse.com/forum/atta...mentid=2044951

The latest pic, cowl painted and engine baffles fabricated using alum from a "Beware of Dog" sign from Ace Hardware.

Here's my latest pics. I made some skis since this thing will be done before Spring. The skis warped during beading so I annealed them in the oven at 350 degs for 3 hours. Worked fine. Then I added stiffeners. Next, add some wheel cradles. I also completed the tail feathers.

Looks great!

Fascinating! I just bought the 50cc (3m wingspa) version of the Paulistinha P-56...and judging from the hardware and fuselage construction it must be from the same manufacturer as your Cub (i.e. ModelCraft).

I love the new paint job and the scale mods! Mine is strictly intended as "test bed" for my Seidel 770, which will later be installed on a 1/4 scale Sopwith Strutter.

Yes, your plane is the identical kit but with different covering. it's made by world models. it's interesting that you would get such a big plane just to be a testbed for another plane! I guess you're not going to use the towel when the radial is attached, correct? Meanwhile, here's a picture of my completed fuselage with the skis installed.