build light

I was looking through my recently aqquired stash of old AAMs and ran across this design called the Mod Pod. On the Cover of the magazine it calls it the
"All-In-One Mod Pod for radio control, free flight, and tether- in 8 versions!"
The article talks about using a fishing pole as a teher and letting out line and reeling it back in while flying. It says that it can be a glider without power or use the detachable engine mount you can use anything from a Pee Wee .020 up to a "hot" .051 for free flight or R/C.
It can be flown as a R/O or R/E as a sailplane or powered plane. Sounds really cool. Looks "Mod" too! (for back then) Are there plans for this still available from somewhere?

Span not listed but appears to be about "52 -"54 inches with a FG arrowshaft tailboom and a FG pod for the fuse.
Has anyone here any experience with it? Did anyone kit it? Does this thread actually belong in the Vintage forum?
So many questions! Any answers?

BMatthews

I remember that and have the magazine "somewhere". If you got the magazine it should have the small scale plan with it. As I recall it used the egg container from the old Leggs nylon stockings. And doesn't it use a Jedelsky all balsa construction for the wing?

My grasp of totally useless tidbits of knowledge never ceases to amaze me. But just ask me to remember the name of someone I was introduced to 5 minutes previous and you'll get a blank stare that totally lacks anything but fear.

build light

I recall seeing an article "For the Tenderfoot" on a towline glider that used the Jedelsky wing. It used a profile "1/8 or "3/16 ply fuse in a profile config where you mounted your radio gear. Looked interesting for sure. Not the same here.
The Mod Pod has a blueprint plan. Blue background, white lines. I need to get a scanner for my computer to scan some of this stuff. The article describes making a fiberglass fuse that looks about "20 long. Not quite like the pantyhose container. I do remember seeing an RCM article once that used these to make blimps for a mobile. I remember this becuse I thought they looked so strange to have that RCM sticker on them like they put on most everything that was built for publicationin their magazine.

The Mold Pod has a conventional built up wing in 2 halves with the center section inner panel between the ribs made from solid balsa block and used a bent nail as a joiner.
The plans show a smaal cork used to plug the hole into which you were to pour lead shot for balancing! I think the design might be updated some and possibly lightened so that lead shot might be eliminated altogether. Lighter tailfeathers( thiers calls for "1/8 sheet balsa) and CF rod for boom as apposed to the FG arrowshaft. The pod might possibly be made different as well. Vac forming? Or using 2 liter bottles like some use to make canopies.
Hmmm This is going to require thought.

Has anyone ever seen one of these things? Surely some one has built one at one time.

BMatthews

Oops, you're right. A quick Google for "mod pod" glider turned up an item on the 'bay. $25 and climbing at this point.....


Shouldn't be too hard to fake it. Simple constant chord wing and a carbon fiber tube for the tail. The pod could be fabed up from epoxy and 'glass over foam and then melted out or make it sort of square and use balsa blocks and triangles to fake it.

I'm also thinking that the plans may have come over to the Model Aviation collection since one magazine led right into the other. You may want to check on that.

Silvaire

My Feedback: (50)

I have one of these Mod Pod kits in my "collection". Like most airplane kits offered by Dumas (other than those that they inherited from Veco) it is not the most well thought out kit. Just the fact that they marketed it as being able to do just about everything should tell you something. I have no idea as to its flying qualities in its various advertised configurations.

Neither the plans nor the kit box make mention of the Mod Pod ever being the subject of a magazine construction article. I have seen Mod Pod kits with either a fiberglass or a vacuformed plastic pod (my kit has a plastic pod). Most odd is that the wing features a fully symetrical airfoil. I can't imagine that it would be much of a performer as a glider. BTW, the span is 54".

It's only "socially redeeming value" (in my opinion), is that it is the only balsa model airplane kit I know of that celebrated the 60's Flower Power era in its name and decoration!

Arlen

build light

Wow! great info.
Now I have a bit to digest..
I do want to have a go with this plane but with my finances as they are right now( Christmas just being here and the rent is due for Jan.) I don't need the temptation of a kit up for auction ( and ending so soon).
Arlen thanks for speaking up when you did regarding your kit. As much as I would like to have the kit, I think I could do better myself than to have a so-so kit. I may wind up getting a kit anyway but for now I need a scanner worse. I think I could improve on the kitted design and work past the flaws you have mentioned. The airfoil shown on the plans shows an Eppler 376 airfoil. It actually lists it as such. It appears to me that this airfoil is a semi-symetrical airfoil. though it has the appearance of being close to symetrical if that makes sense. I bet I could come up with a more efficiant airfoil for this type oif model than this one.
The pod would for me be a lot of trouble to make as I have no experience with Fiber Glass lay up though I have read about it enough. Plus the initial startup of materials is at this point in time is prohibitive.
I need to do some more research or hear some more replies so as to see where to go from here. I wish that auction was over so
]I would not have that bothering me.

Silvaire

My Feedback: (50)

Build Light,

Perhaps I am a bit hasty with my opinion, but I tend to get rubbed the wrong way when any manufacturer claims that their model can do anything you might possibly want it to do...

Virtually every airplane (full scale or model) meets one criterion or performs one mission better than any other airplane. Good or great airplanes also perform a few other missions very well too, but no single airplane does everything better than any other airplane in its class. The Mod Pod might be a fine flyer as a RE R/C sport plane, but I have little reason to think it would exceptional at anything with regards to its performance. If I wanted just what the Mod Pod is, I'd buy the kit and save some time. If I wanted something that would perform well I would probably start with a clean sheet. If you were to "kit bash" the Mod Pod, I think you would likely be left with little but the pod itself. In its general appearance though, I think it is a neat looking design...

Arlen

rainedave

My Feedback: (1)

Doesn't someone launch one of these off the PA scaffolding in the Woodstock film?

Love, rainedav [sm=RAINFRO.gif]

BMatthews

With strong ammonia as found at commercial cleaning supply outlets you can soak sheet balsa and it comes out limp as a wet dishrag. This can then be molded to hold even compound curves of otherwise impossible sizes with ease and it holds it's shape once dry and the ammonia dissipates. A pod made with about 4 to 6 formers, 2 keels, 2 side keels and 4 panels of molded wood is your main pod. Add a balsa block to the nose and another to the tail along with the boom tube and yer done.

Or try your hand at molding glass and epoxy over a styrofoam core. Wrap it all but leave the wing opening and you can gouge and rip and finally dissolve out the foam after it's done. I did my Record Hound cowl that way and have VERY little glass experience and it worked out fantastic. If you can carve and shape a decent nose block then you can the Pod!...

Or there's always the old fashioned way.... planking.

The bottom line is that making the pod is far from impossible or impractical. To make it you need to carve the styrofoam plug along with a few fomers in the rear to support the tail boom and then get some glass cloth, thin laminating epoxy (Not the usual polyester resin) and some disposible gloves and methyl alchohal (for cleanup). From there we can walk you through it.

Here's the cowl I made. It was the first time I ever tried the lost foam method and only about the 4th or 5th ever use of fiberglass for much of anything. It's actuallly very easy to work with.

build light

Indeed I am more interested in its style than for its claim for versatility. Actually by just reading the article that was published I do believe most of its claims to some degree. No where does it state that it excells in any of its roles. It just says that it will do them well. That I believe. In my mind the only thing that really excells is the variety of roles that the author applies to the model. For those who are somewhat limited in their imagination, this plane as it is presented opens new doors to enjoying the sport of flying models. And it is a good selling tool for the model itself to broaden the range of modelers who are often limited in their choicesfor models in "their" catagory of abilities.

I personally am drawn to the style of the plane mostly because of its link to the "flower power" era from which I can identify with. I think it would be quite a throwback to make one of these and decorate it as such using Dayglo colors and "hip" style color scheme as one might see if one were to go back to the show "Rowan and Martin's Laugh-In" It has a free look about it. Not shackled by the usual norms of the time.
I do realise that there were pod and boom planes before then and many since then but this one seems to grab me and say "remember the early 70's?".

Silvaire, I agree I would not be terribly happy with the kit undisturbed and I think you are rigtht on the mark as to me using just the pod from the kit once all the dust had cleared. We can do this plane so much better these days. And with better materials.

rainedav, I don't remember that from the film. Now I need to find a copy and look for it! That would be significant.

rainedave

My Feedback: (1)

BMatthews, that's a beautiful Struck Record Hound.

build light, sorry, that was a poor attempt at humor after seeing those flower stickers.

BMatthews

Thanks. But hopefully it inspires others to greater things rather than looks like I'm trying to show off.

Hint, hint there buildlight....

Oh sorry.... I forgot that this is the smilie of choice for this thread.... [sm=RAINFRO.gif]

build light

Bruce. Indeed your record hound is a beauty. I actually have a great deal of head knowledge of fiberglassing technique. I have read many articles on how-to for many years. Your way of doing it is much more simple than is described in the original article. It reccomends getting 2 pieces of pine in the appropriate size and making a male plug from which you make a female mold and from there you lay up the cloth... I know another way to make it using the lost wax method where you would make a male mold, then use that to make a female mold from plaster. then seperate the plaster halves ( I am leaving out some steps for brevity) remove the male mold, rejoin the plaster halves and pour in wax. this results in a form you can lay your FG over and once done warm it in an oven to remove the wax. the result is multiple compound curves can be made and have the pod in one piece instead of having 2 halves to join together.
I simply have not bothered to try over the years but I believe that is about to change. I should put some of this knowledge to use.
Oh! by the way, to get a really nice finish on the final product you blow up a balloon and force it over the entire project while it cures. It forces nice even pressure over the project and when that comes off it really is slick! very little finishing to be done afterward.
On top of that you can actually put pigment in the resin to make it the color you want as well.
I think I will practice using some things around the house before I buy the FG cloth.
Who knows where I can get some 1/2 oz cloth?

Thanks for all the support!

mclintock

My Feedback: (3)

I've gotten some fiberglass cloth at car parts stores like auto zone or pep boys, also home depot and lowes sometimes sells the stuff..

For fixing holes in boats and corvettes I suppose. I don't recall what the weight is, but the pod is so small it probably cant' matter much..

BMatthews

BL, for this project you're going to need heavier cloth than 1/2 oz. I'd suggest that the Mod Pod will need two layers of 4 oz cloth with probaby a nose wrap laid on first for some extra reinforcing up there before you put on the overall layers.

The balloon thing works great for cowls and smaller stuff like that but for something the size of this pod they are far too small. Unless you can find one of the oversized long sausage shaped ones that could then be forced on lengthways.... that would be a thought. My cowl uses 2 layers of 4 oz with some bitsa scrap in the chin and came out at around 1 to 1 1/2 oz. I didn't use the balloon trick for the reasons mentioned but did not go looking for oversized ones. Also I molded the cloth around and into a smooth lipped air inlet and the balloon would not have helped there at all. I purposely only used enough resin on the layup to barely make the cloth stay transparent. That left a very woven looking surface. I sanded this rough layup to remove lumps, edges and protruding hairs while trying not to cut into the good cloth weave at all. Then a float coat of microballoon and resin was laid on over the whole shebang. When that cured hard I sanded with various grades of sandpaper using both dry and wet sanding to achieve a smooth finish. Primer, spot putty, more primer, wet sand most of it off and finally painted the thing. The worst part was waiting a week or so for the filler coat of resin to harden to where I could sand it without immediatley gumming up the paper.

Finally I chewed out the foam and dissoved the last remnant with some lacquer thinner. A little sanding on the inside to smoothen things and it was done.

cyclops2

Forget the FG cloth. Go to a fabric shop and get any weave or weight or amount of stretch in many colors and synthetics, they practically give it away by different widths. Some of the stuff is like silkspan.

BMatthews

But the strength you need comes from the glass fibers. Using standard cloth will not provide the same strength or stiffness. If all coth was the same then you could laminate on some cotton or nylon to spars instead of carbon fiber.

You need to understand that the strength in composite laminates comes not from the resin but from the fibers in the cloth. The final strength and stiffness of a layup is 95% determined by the fiber type, fiber density and the direction the weave runs.

cyclops2

Then why are all wing failures usually the internal structures in full sized planes. Carbon Fibre is to be used only in high stressed planes pulling high G's .
Mod Pod is not a high G plane. Needless weight and cost for it.
Try to tear painted or Epoxied fabrics on a wing.
YOU CAN NOT DO IT. I KNOW. I try samples on foam wings and fuselages.
The internal structures ALWAYS break first.
40 years ago FULL stunt planes pulled the same high G's as today's with paper or silkspan.
Planes stayed together forever.
Technology can easily become sales gospel.
It is very easy to be drawn into it.
I know. It has caught me a few times. [X(]

BMatthews

Given enough material and resin the pod COULD be made from something like cotton or rayon but it would need to be thicker to achieve the same stiffness and strength compared to using fiberglass. And in this case thicker is also heavier.

There's also one other major consideration. Fiberglass cloth is woven with a looser weave so it can shift the bias angles easily. This allows it to be formed around compound curves like with the Mod Pod without creating wrinkles. While regular cloth has some ability to shift like this it's no where near as good as the fiberglass cloth.

Sure, you could stretch nylon stockings over the form and glass that up but here again to achieve the stiffness you need and the strength means a lot of stockings would be needed. Probably 5 or 6 at least. And when you add in the fact that something like nylon stockings have a lot of voids in the weave that means a lot of resin where there should be fiber. This high resin to fiber ratio means the layup is not as strong per weight as it could be. The best coposite layups use as little resin and as much fiber as they can consistent with having the resin wet out all the fiber. The weave pattern of the nylons also means there's going to be very few fibers running along the surface for very far at all. This results in a very flexible layup for the same thickness compared to the same thickness of fiberglass. If you try this with just one or two layers of stocking and resin you'll find that the resulting shell is highly flexible and won't hold the wing in the proper relationship to the tail properly, would not absorb the engine vibration well and in fact would allow the overall fuslage to flex like a long piece of thin board. Not a good thing.

Remember, this is a hollow pod with no internal structure. The composite skin is all you've got other than a couple of formers. I've also used cloth and glue to reinforce wood structures but this is a totally different use of the material. In the one case the thin fibers are adding skin strength to the underlying wood. In the case of the pod the cloth layup has to be totally self supporting. To do this you need a definite thickness of material.

Think of it this way. A sheet of paper is very flexible. But if you glue a bunch of them together it becomes stiff. How stiff is largely related to how thick the stack is. Composite layups like fiberglassing is the same. A single layer of somethng like 1/2 oz glass cloth is actually quite strong if you try to pull on it but it bends very easily and would not be useful on it's own for a pod like this. A layer of 4 oz cloth is a lot thicker and now has enough bending resistance and overall stiffness when molded to resist deforming even though it's not attached to any wood underneath. And two layers of this same 4 oz cloth suddenly becomes 4x more resistant to bending.

I'm all for keeping it simple too and don't feel you need technology just for the sake of technology. But in this case glass cloth is the best option hands down. The amount of glass cloth to make this pod would be in the $2 range for the small peices required. Resin will be more expensive just because it needs to be epoxy rather than the far cheaper polyester. (polyester eats the foam in a blink) With the minimums to be purchased due to package sizes the cost will come out at about $30 in the end but there will be enough glass cloth and resin left for a couple of more pods or a dozen cowls.

build light

I love all this info and especially the insight!
You both make some good points. I also believe that other materials besides glass cloth could be used. That list would of course be limited as all materials are not equal. Not in strength, weave, texture, cost or availability.
I have thought about using pantyhose material before but that large fact clued me out of that notion. too much space between fibers.
I believe that the strength of the material is more important in this case because there are no internal formers and the structure is about !QUOT!20 long (fairly large in my opinion). This structure forms the structural link between the boom and also the wing. Very important.

For test purposes I have wanted to use dryer sheets. Yes the ones you throw in the dryer to prevent static cling. Check them out sometime. Give them a pull, a stretch, and a pop.I doubt they are as strong as Glass ( few things are) but I do believe it has a chance. For a trial at least.
Bruce, you could always put a balloon over the foam mold if available and the piece isn't too large.That way you could use the polyester resin.
As for the availability of larger balloons for larger projects I have near me a flower shop that has many shapes and sizes. I haven't checked all-mart but I bet they have some larger balloons as well in their party supplies. You might have to look hard for them as the usual ones are more easily found. They do that on purpose I think.

mclintock

My Feedback: (3)

There is a material sold for model aircraft use called 'polyspan' which is actually a dress lining material..
These guys sell and describe it-
http://www.modelresearchlabs.com/
And they sell material you could use for the boom too..

I wonder if fiberglass's small fiber diameter is one of the things that make it popular with composites vs cloth, ever see a cloth covered surfboard? I do have some really strong cloth and paper based phenolic sheets for use in electronics..

Why not make the pod solid foam and cover it with paper and thinned glue or was it water based poly, as mentioned in another thead about a year ago when talking about combat control line foam wings? Does it need to be hollow, or can the pod have a couple of pits for servos in it and two more for the batt and rx? doe-forgot about the tank.. hmm

build light

Actually the pod could be solid foam with cutouts for the servos. Since I cannot share a pic at this time try this:
Imagine a rather slender pod about "20 long yet the top of this pod is flat from side to side with a slight arc from front to rear.after which is a FG arrowshaft with about "20-"22 inches protruding from the rear of the pod which is a slender cone shape in contrast with the nose which is likened to a parabola. Sort of looking like the profile of of a semi-symetrical airfoil upside down Atop this the wing is mounted, the trailing edge about "3.5 from the rear of the pod. It is in front of this the forward facing "Power pod" is mounted. Simply referred to as a removeable engine mount. This particular feature was to add to its versatility.
So there would be no need to have a tank compartment inside of the pod itself.

Back then the pod needed to be hollow for all the radio gear which in early 1970 was generally speaking much larger than we have at our disposal today. It was also pretty much unheard of to mount the servos like we do in many models today with the servo arm exposed.
After writing all this, I just realised that the pushrods would be best going through the boom instead of outside. This is optional of course but would be a cleaner installation.
The original shows an Adams actuator driving a "1/4 in. dowel through the arrowshaft.

I plan on using a part of a broken graphite fishing rod that was given me by some one who was disgusted that they had slammed the tip in the car door. the rest is in fine shape and I have enough for 2 booms, one large OD tapered the other much smaller OD also tapered.
For this I think the smaller one will suffice.

I don't think I will do the pine block inner and outer cones intended to secure the rod to the pod!

mclintock

My Feedback: (3)

Maybe leaving the foam in the pod will help with gluing the shaft. Polyurethane glue should glue that foam to the shaft just fine! As to pushrods, forget that! use pull pull lines.. maybe even inside the shaft somehow, so the lines dont get snagged on grass or tree limbs in landing encounters.

It may be a pain to thread, but perhaps the lines could be run by drilling a hole for the pull pull lines to enter after the shaft leaves the pod, aft of the exposed servo, and another hole just in front of the empannage to let the lines out. Both pair of lines could live happily in the tube i'd think.. maybe the rx ant could live in there too!

burtcs

BL: Why not look at Dickbirds 2005 contest entry, the P-Jay. Basicly the same thing. If it were me (which it's not) I would shape the pod out of foam as has been suggested. I've got some gosimer carbon which would be attached with epoxy FINISHING RESIN (not adhesive) followed by a couple layers of 2 oz. FG cloth followed by yet another layer of carbon. The finishing resin is very sandable when the smoke settles. I you wish and you think your very good, feel free to embed servo mounts etc. in the foam thereby attaching them to the lamination. Come to think of it feel free to laminate the foam. Add your boom while your at it. After everything has cured slosh some acetone or dope thiner around the inside to remove the foam. Viola!!!! Bulkheads, servo mounts, motor mounts (I don't like over-the-wing engines), tail boom, wing mounts etc. are in place.

My layup schedule places the carbon on the inside and outside with the glass in the middle. Carbon is very strong and stiff, FG would provide bouncy resilience to the fuse. By all means double the carbon on the bottom of the fusalage.

Just my worthless opinion - Steve B.

Big Al-RCU

Yep, my rudder-only Mod Pod had an Ace Commander and Baby Adams pulse actuator. The first several flights were pure free flight. Even tho the rudder was happily flapping back and forth, it wouldn't respond to any control input. Then on a (unintended) low fly-by, I turned off the xmiter and guess what? The rudder kept right on flapping. Turns out the pulse rate was close to the natural resonance of the flexible boom and flutter took control right after launch. A bit of counterbalance cured it and I had lots of fun with it after that.
BTW the Dumas kit was only so-so. For example, the punch-outs in the ribs for the spar were so oversize that you could only glue to one side of the cutout. Even so, it flew well enough (slow) and the Babe Bee could get it up to just a spec in the sky.
Al