The following is a discussion of some of the finer points of constructing EPP foam airframes with a definite 'DAW' philisophical bent! There's other methods that work well, some of which are mentioned below, and it's up to you to be the final judge on what suits you. As with anything, experience increases skill, but if you observe some of the tips below, your chances of full success on the first try are very good... Lots of people have done it before you. If you're new to 'foamies' or R/C in general, I encourage you to take a look at some of the sites on our link page. There are several links to sites with construction tips and beginner's guides.
The construction manual that comes with your kit will be quite detailed, and may differ slightly from what you see below. Again, you may be seeing two equally sound methods being expressed. If in doubt, just give us a call or E-mail and we'll be happy to clarify or help you make a decision on which way to go.
Our recommendations on radio equipment for DAW foamies..
A listing of popular adhesives used to assemble EPP foam airframes..
Self-adhesive tapes used in construction of EPP foam airframes..
Hardware and accessories to build the toughest and lightest airframe possible..
Covering materials to give your EPP foam airframes maximum beauty, strength and aerodynamic cleanliness..
This is probably one of the biggest variables to be contended with, and one of the main reasons we don't pre-rout openings for radio equipment in our kits. Anything from the simplest two-channel, AM set to an exotic, computerized PCM system can be used in our kits. Personally, I go for middle-of-the-road capability radios that will allow camber and reflex control with the use of dual wing servos. I occasionally incorporate a rudder, too, but never computer mix it (I use my thumb). Some of my flying buddies use a full-blown Airtronics Stylus and have every conceivable mix neatly computer programmed and toggled on the transmitter. Choice of transmitter is obviously a personal preference thing, but we do have many experienced-based (and how!) recommendations on the airframe systems. Weight is a minor concern, as the airframes are designed to come close to proper C.G. using standard sized equipment, which also curbs cost. Two exceptions are the 1-26 HLG which is designed to use mini sized servos, and the Dragonette MHLG which uses sub-micro equipment. Quality is a concern, since the gear will be embedded in the airframe and can be difficult to maintenance at the field.
Almost any modern receiver is capable of being safely enclosed completely inside a DAW foamie fuselage, except on the smallest models, which require 'micro' receivers. Our suggested placement shown in the instruction manuals has it positioned for best balancing effect in a finished model, and is recommended for better light lift capability by keeping the weight forward and hence the overall weight lower. We've seen all major brands of receivers used in our models with just about equal success. I've personally busted the ceramic filter elements in a couple of my receivers, but they were admittedly placed in extreme duress! Overall, we've been pretty impressed by the equipment produced by all the major manufacturers under the extreme conditions attendant with combat and flight training use. The Dragonette and Mini Warbirds can also be set up using a 27 mhz system with the Hitec SSII transmitter and a micro R/C car receiver like the Dynamite Pro with the case removed.
I like to use standard servos in the Combat warbirds, TG-3, 1-26 2M and Ka6E. My favorite is the JR NES-507 or 510. This is JR's least expensive servo, and is enclosed in their standard size case which is also used for a number of their higher-rated units. The NES-517 is a ball-bearing version of the 507. These have nylon gear trains, but the gears are so large they're still very strong. Another plus with the full-size case is that the bottom of the case will be flush to one side of the fuselage (except the Ka6E). This allows removal of the case screws so that the servo's case top can be removed with pliers from the output shaft side to replace damaged gears with minimum surgery on the aircraft. I've actually changed servo gears at the field in about five minutes on a few occasions. The Futaba FP-148 is almost equal to the JR 507 as is the Airtronics 94102 and Hitec HS-300. We've used all these types with complete success and very few failures. All these servos are capable of fitting completely inside the thickness of the wing panels, too as shown in our manuals. On the 1-26 HLG and Mini Warbirds I prefer the Hitec HS-80, HS-81 or HS-85. These offer moderate cost with acceptable durability and lighter weight for the more petite airframes. The Mini Warbird wings (on dual servo setups) and Electric Aerobats are best equipped with FMA S-80 or Cirrus CS-20 or 21 sub-micros. For the Dragonette, the FMA S-70, S-80, Hitec HS-50, HS-55 or Cirrus CS-10 servos are excellent.
Other popular servos for the Combat Warbirds include the Airtronics 94141, a metal-geared, ball-bearing unit. These are very pricey, and we can't really see any appreciable difference in strength, so we don't recommend them as a big performance improvement. If you hit hard enough and just the right way... You're gonna' bust a servo - I don't care if it's made of titanium! Another often used unit is the Hitec HS-205-BB, a metal-geared, ball-bearing servo that is a bit less expensive than the Airtronics 94141 and is about the same size and weight.
See the Hardware section for a discussion on servo savers, too!
Here's the place we like to see folks spend a little more money. The warbirds, TG-3 and 1-26 2M are capable of running 4-cell, 800 mah battery packs with easy installation and no weight penalty. Another popular setup is a 5-cell, 600 mah pack. DO NOT use nickel-metal-hydride batteries for these planes, as they just aren't as tough as the good old ni-cads! Also, we used to eliminate a switch harness altogether and plug the battery lead directly into an extension to the receiver, but most fliers have now started embedding a switch and charge jack in the fuselage directly above the receiver (except on the 1-26 HLG, Dragonette and Mini Warbird kits). Be careful if you omit the switch, as shorts in the wiring from repeated flexing have led to batteries shorting and "melting down". If you occaisionaly check the condition of the wires and connectors, you can avoid disaster.
For the 1-26 HLG, I like a 270 to 350 mah pack which helps it achieve near perfect balance and gives nice, long flight duration without frequent field charging.
For the Dragonette, either 75, 100 or 110mah packs are fine. The 75 mah packs yield a plane that has a little more aft CG which the real hot-shot HLG guys like quite a bit. For myself, the 110 mah packs balance it just about right, as well as giving a 40 minute flight time without re-charging.
For the Mini Warbirds, a 270 mah pack will balance the airframe almost perfectly.
In the Ka6E, the sky's the limit! We usually run 2000mah packs in such large ships and still require some nose weight.
In the course of construction of an EPP airframe, many different surfaces are glued. Some joints are to raw foam, some to the Coroplast tail parts and some to tape matrix. Foam glues easily, but tape (un-sticky side) and the Coroplast should be cleaned and lightly sanded before joining to remove oils and mold releases left from their manufacture.
Household Goop is one of a large range of adhesives made by Eclectic Products, Inc. Our factory pilots have found this to be the best performing adhesive for construction of EPP foam planes. It provides an excellent bond to the foam, tape and Coroplast. Joints made with Household Goop can be handled in a couple of hour's time, but full bonding requires 24 hours. Household Goop can be found at many hardware and home improvement stores. For technical assistance, Eclectic Products can be reached at 1-800-767-4667. Even if you use other products during construction, definitely use Goop (or it's clones) to attach Coroplast tails, as it's bond just can't be matched by any other adhesive.
Also by Eclectic products, Shoe Goo II is a product very similar in nature to Household Goop except it's much thicker in consistency and requires at least 48 hours of cure time. This product is a little harder to work with than Household Goop, but still provides a very good bond to foam, tape or Coroplast. It can be found at sporting goods stores and some hardware stores.
A popular hobby adhesive, it can often be found in hobby shops and has very similar properties to Goop.
Expensive, but effective. It's another Goop clone and is extremely sticky, which is what we're looking for. It's got a thinner consistency than Goop, so it is a little easier to work with.
This is a glue that's widely available in Europe, and is very similar to 'Goop'. Our European customers have reported excellent results with it.
For sheer speed of construction, hot melt glue, or HMG, from a hot melt glue gun, can't be beat. Although the bond strength achieved is not quite as durable as Goop or Shoe Goo, it is fast to construct with and very easy to repair. Our factory pilots have used the milky-translucent, all-purpose glue sticks. Particularly good uses for HMG are servo and pushrod housing installations. If you work fast and carefully, HMG can be used for installing spars and sub-trailing edges on the wings, too. These are low-stress joints and use of HMG here can considerably speed construction of your aircraft. For high stress bonds such as attaching the tail components or wing to the fuselage, Household Goop is still the big favorite for it's strength and bonding power. Use HMG sparingly, as it's very heavy and the heat can melt the foam if it is applied to liberally. Generally, HMG will set up fairly firm within about 60 seconds of application. Also, particular care should be exercised when using HMG as it can give you a nasty burn in a big hurry - don't let it touch your skin until it is well cooled!
Epoxy is used only for wood-to-wood joints in our models; such as the dihedral brace installation and the root sections of the wing's trailing edge. Nearly any type or brand will work for these joints, so feel free to use what you're most comfortable with. Foam-to-foam joints can also be made with epoxy, but the Goop type adhesives or HMG are still superior. One place epoxy can also be used effectively is on the Dragonette MHLG where loads are so light, that the strength difference is trivial.
Although popular for use on conventional foamie models, our factory tests have found RTV Silicone of very limited usefulness for construction of today's higher performance, harder hitting combat planes and trainers. Since it's drying time is equal to or greater than that of the adhesives mentioned above, and bond strength significantly lower, we don't recommend it for anybody but the pure sport flier.
For construction of EPP foam airframes, 3M Super 77 is an absolute necessity. There's almost nothing capable of sticking to the foam other than this contact adhesive. It is applied to the raw foam prior to placement of tape and / or covering material. 3M 90 Spray Adhesive has also been tried, but was found to be far inferior to the Super 77. It is widely available at nearly every hardware, home improvement, hobby or art supply store.
NOTE - If you're in Europe, the UK 3M representative's number there is 01344-858000. Give them a call, and they can direct you to the nearest distributor of 3M products in your country.
Mark Mech of Aerofoam likes to use Weldwood Contact Cement as a covering adhesive and says it's particularly good to use if you fly in hot climates. He applies it by using a piece of scrap foam as a 'brush'. After that, taping and covering can proceed as usual. Myself, I find the 3M Super 77 easier to apply, but if I lived in Arizona like Mark, I might change my tune real quick since they can experience summer temperatures of over 120 degrees F. I have tried the stuff, and it does work great. Either the original 'liquid' or the 'gel' types are equally suitable.
Even with the incredible strength and flexibility of EPP foam, tape is still necessary to carry and distribute both flight and impact loads on these models. DAW kits come with detailed instructions on taping to give you a strong and lightweight plane. Tape selection bears careful consideration, as it's the life of your plane; especially in combat competition. We've experimented with planes using no tape at all to completely taped to arrive at the recommendations outlined in our instruction manuals. The following products have been found to live up to our engineering requirements.
This is a fiber reinforced packaging tape that can commonly be found in office supply and hardware stores - the same as you would use to tape up a heavy shipping box. The Scotch 3M brand is usualy easy to find, as they enjoy a little bit wider distribution than most others. It's usually seen at the store in dispenser packaging in 10 yard quantities.
No matter which brand you use, for most of our models the 2 inch (50 mm) width is most appropriate. On the 1-26 HLG, and Mini Warbirds, the 3/4 inch (20 mm) width is better.
We use this stuff on the Dragonette to reinforce the fuselage pod. It sticks to the EPP all by itself without use of contact cements and follows contours pretty well. You can also 'blot' it with a covering iron at very low heat which shrinks it a little and increases it bond strength. It's also very UV resistant. It's heavy, and so must be used sparingly.
Ordinary clear mylar packing tape is still useful on EPP airframes as hinging tape and for covering access openings and detailed markings to prevent lifting or peeling. Be sure to use it in areas where it can be easily replaced, as it is not UV resistant and can deteriorate over time in direct sunlight. DO NOT depend on it for structural applications, as it just does not have the strength necessary for these uses. Many brands and varieties are available, but we keep a keen eye for the lightest types possible. Most brands have the film thicknesses printed on the label and we generally go for the thinnest stuff available at the store we're getting it from.
This stuff is awesome; the best hinge tape I've ever found for foamies. If you plan on doing lots of bungee launching of your foamies, then I'd highly recommend this stuff for the aileron or elevon hinges. In the USA, you have good odds of finding this stuff at the hobby shop. If not, then go to Paul Trist's web site at www.planes-wings-things.com or give him a call at (818) 545-7567. Paul makes a whole variety of other stuff; you may find some other things you need made by him, too!
Scotch 600 Transparent Tape (Hinges)
Yes! Available at office supply stores.. Works really great and holds up to sunlight surprisingly well.
Yep..Masking tape! We use masking tape to completely tape-cover the case of any radio equipment or wiring that will be glued into the airframe. It's an extra step, but when the day comes for your war-weary airplane to meet it's final fate, you'll be glad you did it - It makes removal of your gear far easier and it comes out looking as good as new!
On mid-sized models, the cheap 2-56 wire pushrods with nylon clevises, like Dubro #229's, have been the best on dual-servo wings. Since the pushrods are exposed on the top surface of the wings, they're easy to bend back straight if they get tweaked, and the nylon clevis makes a good, predictable, easy to repair failure point. Also, we use Dubro #107 horns at the ailerons.
If you use the single-servo wing option on the Combat Warbirds, with the centerline-mounted servo enclosed inside the fuse, we recommend 4-40 rods with steel clevises and a servo-saver head on the servo. Most combat fliers don't use this setup for obvious reasons but it works great on sport planes. This completely encloses every bit of the radio gear in the plane, and is still very tough.
For small models, like the Extra 300 and Staudacher, simple wire pushrods are excellent.. I show you how in the instructions.
Either way, have a clevis or a "Z" bend at one or both ends of your aileron pushrods. Don't use "E-Z" connectors! These will fail for sure, and I wish somebody would ban the damn things!
For the most of our kits, like the TG-3, 1-26 models, Dragonette, Mini Warbirds, etc. the pushrods included in the kit are perfectly adequate under almost all conditions. For the 48 inch Combat planes, though, there can be a lot of options based on use (that's why we let you pick your own). Here's what we've found...
In our original prototypes of the first couple of kits in the line, we had used the Sullivan red-housing Gold-N-Rods. These worked well for quite a while, but as more pilots began flying combat at our site and engagements became more frequent, we saw them begin to get wiped out as our flying, and our crashing, became more aggressive. The outer housings began to split and fall apart and the inner rod would get kinked up like sausage links. Some of the fliers retrofitted steel wire, spring steel wire (music wire) and cables into these housings that were already installed in their planes and none of them were the "real" answer either, as they'd get all kinked up too! These same conclusions were made for the blue-housing type rods.
So, at the local hobby shop I saw the Sullivan #517 rods. These are the ticket! They're of massive diameter and thick-walled. The housing tubes are made of polyethylene and won't crack, and the inner nylon rod has a wall thickness of 1/16" - plenty tough enough! I've had these installed in two of my regular combat planes and they've performed flawlessly from the start. These rods are stiff, so take particular care to install them without any sharp bends or they'll bind. Lately, I've been running the housings to about the leading edge of the stabilizer in the rear, and letting the inner rod exit there and go on to the control surface to the rear from that point. In the latest version of the manuals, you can see that the rods make a "straight run" from the tail to the servos; that was to facilitate the use of these rods. The Sullivan #517 High Stress rods come packaged with very nice 4-40 all thread stubs and juicy 4-40 Gold-N-Clevises. I've only seen these in 36" lengths, but I'll bet they come in 48", too, as is the case with most of Sullivan's pushrod sets.
So our conclusion is that for sport flying, or if you're shooting for a particularly lightweight model, any old rods will probably suit you fine, but if you're going into hard combat on high-energy hills, you mighty like having the 517's.
Pursuant to our servo stress tests, one of our local pilots discovered Kimbrough Product's servo savers that are used on R/C cars. These slick little units have just the right amount of "give" to virtually indemnify your servos from damage and are low profile enough to fit neatly inside the contours of a DAW foamie. They have an annular spring mechanism that is completely enclosed inside a round, nylon casing and they're practically bullet-proof. These are available at most shops that carry R/C car equipment or you can get them direct from Kimbrough Products, 1322 Bell Avenue, Unit 1-C, Tustin, CA 92780. Fax (714) 258-7426. For standard size servos only, or smaller servos with standard size output shafts.
Covering your aircraft with film covering will significantly strengthen the entire airframe. We've tested several brands of covering material and have found what works. Monokote does NOT work directly over the foam, but can be used over one of the films mentioned below as trim. The materials listed below require that the foam be sprayed with 3M Super 77 prior to application as stated in the instruction manuals. We apply the film with an iron at normal heat, just as you would over a solid sheeted wood airplane.
We consider Ultracote (original recipe, not "Plus") to be the very best material for covering over EPP foam and tape. It's available at most hobby shops in the U.S., and is imported from Germany by Carl Goldberg Models. There's a pretty good color selection which now includes Olive Green.. YES!!!
This stuff is made at the same factory as Ultracote, somewhere deep in Deutscheland. I know that for you Europeans, this is the stuff to use! In Europe, it's available in most hobby shops or it can be ordered from Hobby Lobby. I've never been able to determine yet if they can get it in the coveted Olive Green.
I have never had personal experience with 21st Century Film on EPP foam, but several of our customers have called or written saying it works great. As with the others, apply it just as it says on the instructions that come with it. There's a little better range of colors available than with Ultracote or Oracover, and it can be found in most hobby shops.
Again, no personal experience, but several of our customers have called or written saying it works great. Doesn't require pre-spraying with contact cement. Little bit heavy, but it's paintable and very wrinkle / sag resistant.
These self-adhesive films are excellent for covering the Coroplast tail parts on EPP foam planes. Both come in colors to match the iron-on films. Just stick it on and trim the edges! I highly recommend using these for the tail parts to achieve the best looking and longest lasting results. Ultracote Plus can be used over the foam, too, but I still find that the original style Ultracote is better in that application.
I've got a sort of procedure for shaping EPP fuselages:
Practice your shaping on the scrap chunk before you commit to the fuselage itself. You'll get the hang of it real quick. Always have SHARP blades for your knife on-hand. I use up about three or four blades shaping one fuselage. I can shape out a fuselage in about fifteen minutes, and it looks great. Remember - it's not brain surgery; just a toy airplane! Keep messing with it until you're satisfied. I've seen everything from completely 'un-shaped' to 'very streamlined' on these planes and they all flew fine, but the carefully shaped and streamlined ones are always a little lighter, faster and prettier. Two tools I've also found very handy are a stainless steel utility knife with a blade about 4 inches long and a block of wood with a belt sander belt glued to one side (40 to 60 grit). These two tools in conjuction can also make quick work of shaping a fuselage.
After shaping with the knife and/or gritty sanding block, you can also go over the whole thing with a sanding block and a little finer sandpaper (80 to 120 grit) to get everything fine tuned and looking slick. The secret to successful sanding is to use light pressure and sand in one direction - hard 'back and forth' sanding will nearly always result in the foam chunking out (that goes for all grits).