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Old Jan 30, 2016, 04:02 PM
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Build Log
Vintage Midwest Models Foam Piper J3 Conversion

I acquired a vintage Midwest Models Piper J3 some years back, and it's time to get this guy built and airborne. I would guess it's from the late 70's, although I asked about it in the gas forums and one user said he got one in the mid 80s. But it's got some years behind it, regardless.

It's an extremely interesting kit, in that it's foam. Looks to be very dense, I'd guess EPO...but I don't know. I'll test some later and see.

The manual is included, and it's also *very* interesting. This model was originally intended to be nitro, .049 to .15. The specs shown below say it should weight 35oz...and I don't see how that could be done, considering all the metal hardware. When I post the pics and manual you'll see what I mean.

Other specs:

Wingspan: 45 in.
Wing Area: 290 Sq. in.
Radio: 2ch to 4ch (2ch? Hmm...)

I plan to go electric...motor, esc, battery and prop to be discussed later.

This build won't be one where I can typically get tons done in one evening, for several reasons. I want to take a careful, methodical approach to the conversion, and I have several critical decisions to make . I'd appreciate some expert opinions. For example:

1- Someone had the kit before, and they attempted to start the build. As a result there are some things that might possibly be left in place, and others that absolutely must be removed.

2- The model has a foam molded cowl that is attached...well, half of it is attached. I prefer a plastic cowl myself, but once again a decision must be made. Again, opinions are encouraged.

3- One of the biggies, the wing is designed for rubber bands. I prefer a wing attached with joiners, but again another decision. If I go the joiner route I must fabricate a custom joiner system, wing has nothing that could be used. Pics will show what I mean...

4- A few other details...landing gear, internal setup (whether to use all the balsa they say to glue inside), things like that.

5- How to finish it? The manual says to use "Midwest Styromate"....which I think is some kinda covering, but no info I could find. The pic on the box sure is shiny..looks like a covering like econokote or whatever.

So I'll begin with a few pics of the box. It's darned big...

Next up I'll show what's in the box, and I'll get the manual scanned and posted (you'll love it).

Thanks everyone,
Ric
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Old Jan 30, 2016, 04:23 PM
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That box sure has seen better days! Its a good thing you are building it now! Before much longer it may have committed suicide just to end the agony!

Is it safe to assume you are upgrading to 4 channel?
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Old Jan 30, 2016, 05:11 PM
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I had one way back when, its EPS, there was no other foam used for r/c back then.
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Old Jan 30, 2016, 06:05 PM
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Quote:
Originally Posted by numb_thumbs View Post
Is it safe to assume you are upgrading to 4 channel?
No way, 4ch is far too complicated!

So, 2ch...like use an .049 off of a Cox control line flyer? Without a throttle, just a needle valve? Just rudder and elevator. You'd be running WOT until you run outta gas, then dead stick it in. Fun!
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Old Jan 30, 2016, 06:11 PM
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Hi Ric!

I recently finished a 79in Goldberg cub! I also used electric, so one mod was to have a front hatch integrated with the windshield, sim to Sig Kadett.

No pics, but here's another similar setup with a scratch built Puss Moth I did.

http://www.rcgroups.com/forums/showp...3&postcount=22
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Old Jan 30, 2016, 06:21 PM
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Dang vic, you do good work...gotta get you to show me a little closer look at how you covered your E-Starter. I'm thinking I may cover this one...we'll see.

This one has a hatch, it's the top of the foam cowl. Also a place the former owner attempted to modify. More on that later...
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Old Jan 31, 2016, 10:27 AM
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Quote:
Originally Posted by whowhatwhere View Post
No way, 4ch is far too complicated!

So, 2ch...like use an .049 off of a Cox control line flyer? Without a throttle, just a needle valve? Just rudder and elevator. You'd be running WOT until you run outta gas, then dead stick it in. Fun!
You should put that new Hitec 8ch to work! Make it 5ch, independent servos for each aileron will give you flaperons. Easy to do, and the plane will be much nicer to fly.

Econokote is available in Cub Yellow. EPS foam is easier than EPO in my experience, it is finer grained, easier to fill and sand for a smooth finish. I did my Goldberg cub red and gold, just to be different. Kind of tongue in cheek pylon racer color scheme.
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Old Jan 31, 2016, 10:59 AM
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Quote:
You should put that new Hitec 8ch to work! Make it 5ch, independent servos for each aileron will give you flaperons. Easy to do, and the plane will be much nicer to fly.
Yep, good idea. This guy has servo slots molded into the wings, but not for servos, they say to use a servo arm swiveling with rods....but the holes are big enough for a full sized servo if ya wanted to do it that way. I have a couple speedy birds that could really use flaperons...the Lancair for one.
Quote:
Econokote is available in Cub Yellow. EPS foam is easier than EPO in my experience, it is finer grained, easier to fill and sand for a smooth finish. I did my Goldberg cub red and gold, just to be different. Kind of tongue in cheek pylon racer color scheme.
Well, I have 3 Flyzone Super Cubs in yellow...the original I got, and two others I bought from a user here who had stocked up on parts (at a major steal no less). So I'm in yellow overload. This one will be dressed in my dad's J3 colors, which I'm sure you recall were grey with a red stripe and numbers.

I'm gonna spring for some nice graphics from Callie Graphics for this one.
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Old Jan 31, 2016, 11:01 AM
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sorry, duplicate post
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Old Jan 31, 2016, 07:07 PM
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OK, for today...

What's in the Box

Pic 1 shows the top side of the wing. Note the contours, even on the ailerons. They've pretty firm, and they look great, so I plan to use them rather than balsa.

Pic 2 shows the underside of the wing. Note the roomy servo slots and cable channel. The hole is large enough for full sized servo.

Pic 3 shows the fuse halves. Note there is no wing joiner, the wing sits on top of the cockpit, holes for rubber band dowels are visible.

Pic 4 shows a closeup of the inside of the fuse. This is where the previous owner attempted to start the build, and he installed the landing gear mount and the bigger piece of wood on top of the mount. I don't know what kind of glue he used, it's actually kinda rubbery...it doesn't feel like epoxy which should be glass. Still it's very solid. I have to decide whether to keep this or remove it and redo the landing gear mount. I don't want the landing gear coming off during touchdown...

Note the channel for a motor mount, it's in the fuse top as well. it's angled, and will make things *way* easier.

Pic 5 is the top cover of the cowl. The previous owner attempted to glue a piece into the slot, but he just reached down and broke a piece of foam off his beer cooler. The model foam is very dense, but note how far I can pinch his "mod" in Pic 6. Extremely crappy, MUST BE REMOVED!

Pics 7 & 8 show the fuse assembled. I have some good foam from a couple crashes, I can use it if go this route to shape a better insert. It doesn't have much for ventilation, but it' definitely doable. I still prefer a plastic cowl, but one could argue this should be used for authenticity.

Pic 9 shows the tail assembly. The vertical stab has some gouges, likely from laying against the landing gear. Very good though.

Pic 10 shows the wood called out in the instructions. I likely won't use all of it...not sure how much yet, but some will be used.

Pic 11 shows the mass quantity of metal. Metal landing gear, metal motor mount, metal wing struts (I like 'em). Lotsa hardware in this kit.

Remember the box said 35oz...!

OK, that's it for tonite. This week I'll be making a couple decisions and moving forward.

Stay tuned...!
Ric
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Old Feb 01, 2016, 10:44 PM
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Some may be thinking as of now, meh...this just looks like another foam model. This post is where you find out that's not quite correct.

The Manual

I love looking at this document. It's really an extremely radical, cutting edge kit for the time (early to mid-80s as someone else here said). In the world of balsa, a foam plane! It's a fair guess that seasoned modelers wouldn't be too quick to take it seriously. Little did they know where foam would take the sport.

It's so interesting to look at the layout on pages 8, 9 & 10...the gas motor, fuel tank, full sized servos...it seems funny to think about using that stuff in a foam plane now, but again cutting edge back then. And not only the internal hardware would be large and bulky, but also the receiver and the NiCd pack. Looking over the instructions, some of the assembly is interesting, but a lot will be tossed of course.

Another item is Styromate, which is discussed on page 11. It was an undercoat of some kind...they say to put on two coats, and the model is then painted. They call out Pactra, which is still sold.

The models shown on the back look pretty cool as well.

So now, onward to the build. First, gotta weigh it, and see what I'm working with. From there should be no problem...I have a several motors, ESCs & props on hand for whatever the result.

Stay tuned...
Ric
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Old Feb 02, 2016, 07:46 AM
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Quote:
Originally Posted by whowhatwhere View Post
It's a fair guess that seasoned modelers wouldn't be too quick to take it seriously. Little did they know where foam would take the sport.
The only foam I saw in the 80's (other than Cox .049 elevator/rudder only jobs) was some sheeted foam wings on pattern planes and the Sig Kougar I believe . They were so heavy many folks simply were not interested.

I also remember the first electric that showed up at the field back in the mid 80's A 2 meter powered glider with brushed motor and 6 cell NiCad pack right out of a car. It was certainly no power house but it was fine for a glider. NO ONE was impressed with that though! Yeah, I did NOT see how *that* was going to evolve and transform the hobby!
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Old Feb 02, 2016, 08:10 AM
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Quote:
Originally Posted by numb_thumbs View Post
The only foam I saw in the 80's (other than Cox .049 elevator/rudder only jobs) was some sheeted foam wings on pattern planes and the Sig Kougar I believe . They were so heavy many folks simply were not interested.

I also remember the first electric that showed up at the field back in the mid 80's A 2 meter powered glider with brushed motor and 6 cell NiCad pack right out of a car. It was certainly no power house but it was fine for a glider. NO ONE was impressed with that though! Yeah, I did NOT see how *that* was going to evolve and transform the hobby!
Another thing to note is the fuel itself...as that liquid is consumed the CoG will change radically. Not as bad on a larger, heavier balsa model...but on a lighter foam plane it would be a considerable nuisance. You'd be taking off with a lot more weight than when you land.

But it's pretty cool when you think about it...within 10 years the market would be completely changed. And for me it really hits home...I had a balsa trainer in the late 90s, but my real flying education came later when I discovered all the various foam planes and started noodling with them.

Funny you mention a glider with a brushed motor and NiCd pack. I have a Great Planes Spectre I got about 15 years ago, and that's exactly what it came with...big ol' brushed motor and 6-cell NiCd pack that's so heavy it feels like a brick when you pick it up.
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Old Feb 02, 2016, 08:44 AM
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Quote:
Originally Posted by numb_thumbs View Post
The only foam I saw in the 80's (other than Cox .049 elevator/rudder only jobs) was some sheeted foam wings on pattern planes and the Sig Kougar I believe . They were so heavy many folks simply were not interested.

I also remember the first electric that showed up at the field back in the mid 80's A 2 meter powered glider with brushed motor and 6 cell NiCad pack right out of a car. It was certainly no power house but it was fine for a glider. NO ONE was impressed with that though! Yeah, I did NOT see how *that* was going to evolve and transform the hobby!

I have a 1970's Ace High glider, version 1. 70" EPS wing, originally designed for Cox .049 on a pod. No throttle, single channel to rudder.

I was given the kit, recovered from an attic, and built it with rudder elevator, and folding prop electric up front. Flies great!!

I coated the foam wing with clear acrylic. Econokote red and navy underneath the wing provides contrast in clouds.
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Old Feb 02, 2016, 08:52 AM
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I have a 1970's Ace High glider, version 1. 70" EPS wing, originally designed for Cox .049 on a pod. No throttle, single channel to rudder.
I'm trying to fathom how it would be flown with an .049 engine with no throttle...with a glider that'd be tricky, pulling WOT until the gas ran out.

With *any* plane that'd be tricky...

Quote:
I coated the foam wing with clear acrylic.
Well, I was thinking about this model last nite, and I'm not sure I can cover it. The fuse wouldn't be a big deal, but the wing with all the "canvas contours" would be a lot more difficult. Trying to get all the wrinkles out would be a pain, and your advice is critical..."work swiftly, don't linger too long in one spot". So I tested a couple different clear coats on some scrap foam. May be easier to clear coat it then paint rather than attempt to cover it.
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