themadmax

My Feedback: (70)

Hey,
Thought you'd enjoy the extent of MADness I'm capable of in 1/2A. I'm just finishing a scale P-51A with a 36" span, .049 Cox engine. She's completely aluminum covered, full cockpit, complete articulated pilot, (Stick moves with control inputs) and scale static landing gear...from my plans which I'll try to post along with pictures.

Comments, snide remarks accepted.

combatpigg

My Feedback: (3)

I read about an aluminum covering system that goes on like aluminum duct tape that the large scale builders use. Panel by panel. Is this how you did yours'?

When you get yours' done we'll tie some streamers on and go at it, I'll supply the beer.

I can't wait to see it, it sounds like a masterpiece!

themadmax

My Feedback: (70)

This is my third attempt to upload pics...rrrrrr! I wrote an article for MAN that ended up being a 2-part online article "Covering RC Aircraft With Aluminum". In it I outlined the process for using aluminum duct tape as well as other aluminum covering techniques. You can cover a whole wing sheeting (Balsa or my preference, Mylar) on the board, at one time with strips and then scribe your panel lines and roll on your rivets. Wherever you don't want the joint to show fill with a small brush and some filler like balsa filler. Once dry sand with 400. DO NOT PRIME! I made that mistake and had to rescribe all the panel lines and redo the rivets which is nearly impossible as these are micro indentations with precise spacing so a lick off's a lot! I did the whole side of the P-51A to the firewall with one piece. The 2" limitation is only a bugger with wing panels as they're usually wider at the root end than 2". Most wings are skinned with a joint at the main spar so put a line there and go from there towards the LE and TE. Individual panels are only necessary at compound curves like the radiator and bottom cowl of the P-51. Then, make sure you tape off the adjoining panels before putting a piece on otherwise you'll find the cutoff bonds to the underlying aluminum and makes a helluva mess. A very sharp Xacto is required. I use clay modeling tools to stretch and shape the aluminum which is very malleable until stuck down. Then...forget it. If you've got too much material you can't shrink the material so overlap/wrinkles occur. Always look at the complex curve as where does material have to grow...at the edges or the center. Stretch it and work it where it has to grow. Another main trick is how you handle the aluminum tape because it's not user friendly, at all! Have a smooth (Glass is good) area that's dust free to lay the required piece of tape on, shiney side down. Then, without bending it at all, get a corner of the backing separated and lay the piece down. With tweezers peel back enough to put the blunt end of an xacto on the sticky tape and carefully peel the backing directly away and level from your corner. The piece of aluminum tape will lay flat without any wrinkles or dents which is very important because any wrinkles or dents are going to have to be worked out of the material. Tear off two fingerhold sizes of the backing you just removed and carefully attach, glossy side to sticky, some pieces to allow you to position the piece where you're putting it. Once it touches, that's where it's going so it's a real steady-hand kinda deal. If you touch it in the wrong place, pull it off and start with a new piece. (You'll never get the wrinkles out.) Let me know if you're interested and I'll send you a copy of the article.

I'm going to try the upload thing again.

Well...it ain't working, again@#$$!@ my email address is: [email protected]. Send me your email address and I'll send you pics, directly, since this site's not functioning correctly.

buzzard bait

Some web browsers will not upload pictures--Safari absolutely will not work, maybe others too.

Fascinating stuff--I'll send a PM.

Jim

themadmax

My Feedback: (70)

The bugger is that I've uploaded pictures before with no problem...maybe it's a stars alignment thing

old git

I have a MAC Power Book with both Safari and Firefox and both refuse to allow me to upload pictures.

My wife's computer, a Dell is running Explorer and she has tried Firefox. She lost her access to the favourite addresses using Firefox so is back on Explorer.

If I need to send a picture I have to wait for a timeslot on her machine. To do this I have to make a CD and take it to her machine and send pic's via Explorer.

I think I have seen mention of a metal covering called metalskin?

Lots of luck to ALL.

old git - - - - aka John L.

themadmax

My Feedback: (70)

try it again...YEAHHHH! IT WORKED!

old git

Oh Yes indeed it really did work. There's more detail than I would have expected of a 1/2A model.

It looks superb, how much of a penalty is the weight of this covering?


old git - - - - aka John L.

themadmax

My Feedback: (70)

John,
Funny you should ask. I was very concerned about that as this is an airplane and I'm known for airplanes that fly well. My wing weight, with Mylar on the bottom, servo, mechanicals installed was 3 oz. I just weighed the stbd. top skin (Mylar/alum.) and it's 3/4oz. I'm still in the process of sanding off unwanted Mylar/alum. I'd rather used .002" Mylar on this size craft but .005" was what I had on hand. I'm going to speculate that with the .002" Mylar I could knock a little over 1/3 off the "skin" weight. I was shooting for 16 oz. so it's going to be close. At that weight my wing-loading still a respectable 10.66 oz./sq. ft.

Attachment is the wing skin in progress. It get's purtier the more you sand!

BMatthews

That's looking really nice so far.

Be sure to run the antenna outside of the fuselage by using the scale mast to feed the wire up and out so there's more exposed. The aluminium tape will act like a shield otherwise.

themadmax

My Feedback: (70)

Here's what the wing will look like...not finished but close.
I've also enclosed a pic of the static tailwheel in progress. It's made of for the most part of aluminum, as well

combatpigg

My Feedback: (3)

I like the aileron linkage and of course those rivets! That sure has a real look that iron-on covering can't touch.

old git

I am having a little trouble understanding the sanding process, I think I need to see the result before I can follow your objective.

It certainly has the LOOK of a display model rather than a flier, even if it is light enough. It should make some take notice.

Please keep going, maybe I need to have read your bit on metal covering to understand but I haven't done that yet.



old git - - - - aka John L.

mylamo

My Feedback: (1)

Stunning,to come out at a flyable weight at all
is in a word ,stunning.
Ralph

themadmax

My Feedback: (70)

When you scribe and "rivet" the material you're displacing it to somewhere and, with a hard substrate, it's outward. The result is scribed "joints" look like you plowed a furrow and "rivets" look like little volcanos. You can work it down with a tool but that material's still got to go somewhere. Simply sand it off w/400 grit. You have to put filler where you've run amok with a scribe or rivet as well as the 2" part line when your panel's wider than that. (Use a sanding block, always!) It's a relatively flat surface and most people's fingers aren't flat. Try it and you'll see how much better it looks. You're also making it lighter. Enclosed is a photo with sanding evident.

As to the flyability...the radiator duct goes through the fuse and exits in the scale location so the basic airframe is just as aerodynamically smooth as the real deal. The A and B model P-51's were actually more aerodynamically efficient than the bubble variants. IT WILL FLY! I've never in 30 years of designing and building had one that didn't fly and fly well!

old git

I've read what you had to say about metal covering and it makes a lot of sense now, especially it sounds good for warbirds "in service". Really wonderful for weathered effects.

I've remembered the other material I read about, "FLITE METAL". It goes in a rather different direction but since I have tried neither I cannot say too much. It is enough for me to say I will at some time in the future have a go at some of these techniques.

Flight Metal calls for a hard surface sheet balsa with a glass epoxy finish but again that is not something I have tried. I does appear that glass epoxy can be a lighter finish than I had ever imagined.

Thanks to RCU I am finding many techniques as possible when I had previously ruled them out.



old git - - - - aka John L.

themadmax

My Feedback: (70)

John,
One of the concepts I'm furthering with this build is the paradigm shift away from the balsa/epoxy/glass skinning process. I've got a 1/5th scale Beaver and Birddog I'm in the process of kitting which are covered with .005" Mylar...not balsa, and they'll weigh about 1/2 of what traditionally skinned aircraft weigh. I did an experiment several years ago to determine the most realistic, and lightest, way to cover aircraft which were, in full scale, Alclad covered. I finished a 1" square of 3/32" balsa in the conventional manner of fill, glass, fill, prime and then weighed it. I then took a piece of beer can aluminum (1" square) and weighed it. The aluminum was approx. 1/2 the weight! I've not yet repeated this weight comparison with a piece of Mylar/alum. tape skinning but, with a tensile strength of 32,000 p.s.i., the skinning is extremely strong, bi-directionally, very light, and very scale in appearance. A tremendous benefit is you can put the panel lines/rivets on the skinning prior to attachment to the structure. It's ready to paint upon attachment instead of all the filling, sanding, nasty fumes, etc. of a balsa/epoxy skinning process (Afterwhich, you still have to put the FliteMetal on the structure, scribe panel lines, rivets, etc.). I'd much rather do my skins flat on a board and then put it on the structure as opposed to doing this detailing on the structure.

My intent is to build a whole series of these little "Masterpiece" quality, 1/2A size fighters with the same attention to detail and scale fidelity as this P-51A. Obvious subjects include the F-4U Corsair, F-6F Hellcat, F-4 Wildcat, P-40, P-47, FW-190, ME-109, Spitfire, etc. They're easily transported, the perfect size for hanging at the office and they FLY!

A prerequisite is to draw all my own plans because all the longerons/formers have to be in their scale location in order to panel the aircraft per the full scale aircraft and have it look "right". It's a major paradigm shift in design as well as construction.

old git

Ahhh, now I get it. I was beginning to understand the process but doing it "on the flat" is the real kicker. I was still thinking in terms of panel beating, though we made extensive use of card templates. It becomes a true monocoque - nearly.


I love the idea of a flier that looks good when ceiling hung or on a desktop. I have a tendency to keep a flier and go on to the next but sadly only a tendency, hangar rash takes a huge toll, nearly as much as landing.

Keep us abreast of your kit developments please.



old git - - - - - aka John L.

themadmax

My Feedback: (70)

John,
It IS a true monocoque structure! My 1/5th scale Birddog is totally stressed-skin with very little substructure other than to hold the skin in place. (Hard points are waterjet-cut 6061 T6 aluminum.) The wonderful thing about this concept is that it yields an extremely strong, light structure that's already finished! Add rivets and some odds and ends and she's ready for paint.

Medium grade balsa tensile strength is around 2890 p.s.i. while Alclad tensile strength is 28,000-34,000 p.s.i. At 32,000 p.s.i. Mylar is just Alclad you can glue, easily. It also has a much better memory modulus as well as overall stability.

Hey! A fold and fly RC airplane...hmmmm?

old git

Hi 'Max,

Are you advertising the kits anywhere? I am lazy enough to seek instant gratification while convincing myself I am building.

I have a pretty large stash of boxes awaiting my kind ministrations but what the heck, treat life as if it goes on forever!


As a youngster I made a number of card models, I still have some "Micromodels" postcard size cut & fold kits, very satisfying.

Thinking on the same lines, I had a number of the "Frog" pressed paper and aluminium rubber powered models and still have,
in pride of place an "International Model Aircraft" models Compressed Paper, Rocket powered, Target Drone, about 48" span &
50"+ long. Bright yellow colour and never shot down.



old git - - - - aka John L.

themadmax

My Feedback: (70)

John,
If it were me, and I am I'm not spending another minute filling and sanding balsa, thank you! lol The designers of the A/C we're "duplicating" at a smaller scale already invented the wheel...why are we using, essentially, boat building techniques for airplanes which need be as strong and light as engineering/materials will allow with minimal handiwork. No aircraft designer ever put an extra longeron/former/panel separation where one wasn't absolutely required so why not simply replicate their wheel.

As to kits, I can sell you the plans and a short kit for the 5th scale Birddog as well as required aluminum. The only wood you'd have to supply is the longerons, spars and spar webbing (1/16" & 1/8" sheet). I have a source here in America for the same plastic that DuPont has put the moniker "Mylar" on but it's much less expensive. Once framed up, it would take about 2 evenings to skin and be ready for rivets or primer. Beginning next month I'll be selling the 1/5th scale Birddog as a 6 piece ARP..(All Ready for Paint). I think that's a MADMAX original...It will have a cowl, fuse, 2 wings w/hinged ail/flaps, stab/hinged elev., fin/hinged rudder. Main/tail landing gear/wing struts are built by the "builder/finisher. It's a Scale Master's platform which, with some rivets, panels and interior detail work, capable of competing with the best in static scale judging while having the flight characteristics of a Giant Telelmaster to garner those scale flight points. I'm cutting Mylar templates for the skinning to keep these ARP kits very affordable.

The Fold and Fly planes fascinate me. Obviously, it's not new, just brought around again. I'd like to see pics of the Fold & Fly's as well as the Target Drone.

At 1/2A scale the Fold & Fly concept definitely has merit. Hey, I have a jpg of a Fold & Fly birddog you've got to see.

old git

Hi 'madmax,

Ready for paint? that Bird Dog looks more like READY!

What IS the idea then? flat pack ARTF?

Your madness has been so very interesting, waking up brain cells that have been dormant for some time,
not all, just those around these ideas of yours that I share in a very nebulous fashion.

"She who must be obeyed" is off on Monday to look after grandkids while daughter and spouse kill some more brain cells.
That will give me access to her computer without interruption and I can then send pics of the Target Drone. My MAC simply
refuses to allow me to upload pics.

I may some time later find advertisments for the Frog RTF rubber models.

How much would the Bird Dog kit cost me?



old git - - - - aka John L.

themadmax

My Feedback: (70)

I'll email you directly concerning the Birddog.

"FLATPAK ARFF"...Almost Ready to Fold & Fly...can we trademark it

I'm thinking a Mylar/Aluminum laminate with formers/ribs/skinning die cut, rivet/panel lines laser-etched, color/markings/nomenclature printed...Elmer's glue, some sticks and in a couple of evenings one could have a "Stunning" 1/2A size scale ship! YEOW! That'd ROCK!!!. Once setup costs are covered, the kit cost and shipping would be negligible.

It's getting MAD I tell you, simply MAD!!!

jeffie8696

Max you are a kindered soul. No I did'nt build mine[sm=cry_smile.gif] and it don't fly but it shore is beautiful. I'm not one for the D model like EVERYBODY else. And of course the P-40 is THE most beautiful aircraft ever built. I want to see flight video and everthin. Beauty!!

themadmax

My Feedback: (70)

Latest pics. I'm just finishing up the opening canopy and scale lock mechanism...small boogers they are!