Author Topic: building with foam cores (Read 4211 times)

Steve Schoenecker · « **on:** February 02, 2017, 03:46:39 PM »

Ok...

I have bought some foam cores for my stunt trainer. Got gotcha streak cores with tip extensions. I am building stout profile airplane around them. It will be a little heavy .. don't know how heavy yet... but heavy. I think that I am going to use my FP .40. If too much power, I can switch to one of the .35s I have.

My question: How do I join the cores and what covering? I used titebond to glue the tip extensions on.. seems to be fine. I bought balsa and basswood strips for spars. I don't know if the basswood would be better? I thought I would cut out and use about 6 or 8" doubler under the spars at the center.

Do I just lay the cores in the cradles and glue together? Then what? Fiberglass a couple of layers on the center section? I have read that maybe a couple of layers with bottom layer wider than top layer. What about covering? use SLC? or monokote? Balsa sheeting?

Years ago... I watched some RC guys covering foam wings with something called (I think) Tag Board??? looked like poster board.. they used contact cement to glue to the wing. looked like it worked well... gave a nice hard smooth finish.

I bought 4 sets of cores... I will build a couple of these trainers... I am getting ready to learn stunt again. I want to set one up for my grandson too...

thanks!! Steve

Howard Rush · « **Reply #1 on:** February 02, 2017, 05:11:44 PM »

I covered bare-foam planes with Solarfilm. It was sold in the US under several aliases: Flite Kote, I think, was one of them. It is low-temperature stuff. Mono Kote works at too high a temperature. You'll melt the foam before it will shrink. Some Solarfilm colors were way heavier than others. As I recall, the fluorescent colors were heaviest, then white, then dark solid colors. The lightest were the transparent colors.

Glass in the center may not be necessary, but use epoxy, rather than polyester, resin if you use glass.

Tim Wescott · « **Reply #2 on:** February 02, 2017, 05:53:16 PM »

You do NOT need to build it heavy. Phil's cores are great if you just glue them together and use hard balsa spars the size of the spar notches. I use a center joiner for the spars, as you're planning to do. Cover with Phil's SLC, or with Howard's Solarfilm. You do NOT need to use some heavy paper or cardboard covering on the wings -- you want an airplane, not something to send a baseball out of the park. You do NOT need to slab on the weight of any fiberglass on the center section -- either you're going to land normally and not break anything, or you're going to post-hole and break everything. The less stuff you have glommed onto the thing, the less will break and the easier it'll be to repair.

Gorilla Glue (the real foaming stuff) works great. Original green (which isn't that bad once it foams up) or the white stuff both work great. Just spritz some water on the foam as a catalyst, put on the glue, tape it all together, and wait for a bit. If you didn't pick up all the bits of foam from your latest crash, you can mix the glue directly with water just like epoxy (except use a bunch of glue and a teeny spritz of water). Then you can dribble the catalyzed glue into your hole, let it foam up, and trim the result.

Read this thread. This has been a fantastic plane for teaching someone to fly, and it is by no means heavy. It's been crashed and repaired about a half a dozen times, and it still flies great. Aside from the fact that it's light and straight, there are two features that I think make this plane a really good trainer. First, the control system is entirely hanging out in the breeze, meaning it's easy to install, repair, see, and understand. Second, because the wing needed to be low anyway (due to the control system hanging above it), the fuselage is only attached to the top surface of the wing. This means that when the plane does get post-holed (and it has), the wing breaks into a few great big chunks that can be easily repaired with Gorilla Glue.

Steven Kientz · « **Reply #3 on:** February 02, 2017, 05:56:38 PM »

If you can find plans for the Yankee Nipper combat plane, it has some ideas using drywall mesh and wood glue. Very durable albeit heavy. I also dowel the joint between halves. Check in the combat section someone might have plans or construction article.
Steve

Steve Schoenecker · « **Reply #4 on:** February 04, 2017, 08:13:32 AM »

Thanks for the info...

I have learned a lot already. I have read your thread a couple of times, Tim... exactly what I needed!! Good looking airplane. I had been thinking about making engine bearers to allow changing motors... I was excited to see yours.. I have already started making a set.

Because it seemed like a good idea at the time... I used a piece of 1/4 x 3" poplar for the main fuselage member and added 1/8" balsa to the sides... it is kind of heavy... was 8 oz after gluing up fuse... now with pretty much completed fuselage, tail and glued up wing 19.6... no engine, tank, LG or controls... we will see. did you say yours was 43.2? Hopefully I can be less than that??

I bought some 1/2 balsa, and some 1/4 basswood... so I can probably make a lighter fuse for next one.

I started a thread a while back to learn about brodak's ares... the consensus was... build a foam wing trainer first... That is where I am now.

I ordered some SLC to do the wings. I will post some pics when I get farther along...

again... thanks for the help!!

steve

Fredvon4 · « **Reply #5 on:** February 04, 2017, 09:37:23 AM »

Steve

I have built 3 of Core House RST
2 as the full kit from Phil and one a copy using spare set of wing cores

The RST kit fuselage is 1/4" bass wood with maple engine mounts that I add aluminum to for the engine. The doubblers and Canopy/rudder are lite ply sections, and the wing saddle is wide strip of 1/32 ply. Glue, and 3 coats of Rustoleum rattle can paint they weigh in at 7.1 oz

MY copy of the fuselage was same profile using 3/8th Balsa skinned with carbon fiber veil and 1/64s ply sides and top/bottom. and generally built up same as kit version... it came out at 6.8oz and is about same stiffness

Both of these were weighed with the stab/elevator + canopy/rudder installed

For training I suggest not wasting weight and time on making the wing cores look real pretty or the grand effort to hide the popcorn foam look...with lite weight spackle, just adds weight with zero strength gain

If white foam annoys you too much, watered down craft store acrylic paint will tint the foam for very little weight gain

First time I used SLC on full foam wing using tradition perimeter sealing I trapped too much air requiring pin holes through the covering to seal it all down
I changed to an unconventional method of laying the covering in place and starting in the middle ironed out toward all the edges not caring about eventual over lap or trim lines... The SlC is so thin than once down and overlapped you can hardly find the edge lines

Steve Schoenecker · « **Reply #6 on:** February 19, 2017, 07:33:21 AM »

starting to make progress.... I glued the wing together and it is fine.... I saw that I should glue a wing saddle to the center section... I used 1/32 ply a little over 1" wide. I wondered if I should cover first or glue the wing saddle strip on first??? I glued the saddle strip. I covered the wing with SLC yesterday... I did find the directions that said to put a strip on the trailing edge and leading edge and a couple of layers on center section. I'm not impressed with my covering job. having the wing saddle in place make it very difficult to do a good job around the center section. also kind of funny looking around the areas with multiple layers. However... it is tight and seems firmly adhered everywhere except where the wing saddle strip is. I tried turning the iron over to stick it to the side of the 1/32 ply... not enough to stick to, I guess. it is raised up a little in places... It is what it is... I know I will crash etc...

I think next time.. I will cover first so it will lay flat.. then I can poke some holes to let glue penetrate the covering to hold the wing saddle strips on... This was my first experience with SLC... It seems to really stiffen the wing... I am getting excited.

I made an aluminum landing gear. Wish I had a brake... I have been watching "build your brake videos"... I may try to build one. I took some popsicle sticks and mounted in vise and hammered to shape with a block of wood. When I build the Fuse... I extended the motor mounts way back toward the wing so I could mount the LG to the hardwood. This should be good. I made a couple of Alu brackets that will mount on the landing gear bolts to hold the clunk tank.

BTW I am using 4 oz Sullivan straight front clunk tank I plumbed it as uniflo as in Sparky's video. Don't have muffler at this point.. so will use suction.. Might add tongue muffler later and try pressure. I have never used muffler pressure... I have used crankcase pressure in combat planes years ago... and pacifiers & bladders...

Put first coats of paint on fuselage yesterday. I did not use any sanding sealer... just DC540 primer... there is some wood grain showing.. but not worrying about that this time... I don't think I will paint the wing either. Maybe a couple of red strips on the tips or something...

I will be using the FP .40... I decided that this will be the motor... so I am not using the engine mounting blocks... I can add this later if I need to. Also... when I cut the doublers.. I cut out both sides for the motor... OOPS... I thought about adding another piece on inboard side.. but decided against it... That made me wonder about cutting out the doubler over the motor mount to use the engine mounting block... I didn't want to weaken it??? I didn't think I wanted to just put engine mount block on top of the doubler... it may raise the engine too much??? Anyway.. I am going to mount the engine normally

Question: What size venturi should I use? also what prop... I have some 10-5 and 10-6... Should I get some 11-4 or something? The FP is an RC version, so I will need venturi and NVA. Don't really know what to expect. I guess it depends on the final weight?

I weighed the wing complete with 1 1/4oz wing tip weight and the adjustable leadout guide, bellcrank and leadouts (no pushrod)... 11.3 oz last time I weighed the Fuse... 8.4 getting close to 20 oz without paint or engine etc... I saw in Tim's thread that his weighed 42 oz I think... Engine is a little over 8 oz this one may approach that...

I did get some CF pushrods and ends... I asked about pushrod ends etc in http://stunthanger.com/smf/building-techniques/pushrod-parts/

I'll post some pics when I get farther along...

Fredvon4 · « **Reply #7 on:** February 19, 2017, 11:29:31 AM »

Couple of random thoughts:

RSM sells Duralum Landing get that fits quite well and not very expensive

http://www.rsmdistribution.com/index-2.htm

SigMfg also has a set that works well for a LOT of our different profile designs...they are sold as the replacement set for an Ultra Biplane that is no longer offered

My Rugged Stunt trainers (3) came out 37Oz to 42Oz and each has smaller OS power...one a LA 25 and two using OS 25 FPs- one iron lung, and one ABN version, all turning APC 9x4 props

Plenty of power for my "fly only calm to 10Mph" windy days

I am sure the OS 40FP will work, but IMO, a lot more power than needed...

A lot of folks think the Thunder Tiger Cyclone 11 x 4.5 Prop is a great prop for that FP 40 engine on a typical Nobler wing and weight stunt plane

I am sure there are plenty of APC or other brand prop equivalents--- someone will recommend

Member Rick Bollinger bought a significant qty of the TT Cyclon 11x 4.5s and offered them for sale here ON SH

If this is a desired prop, I would drop him a PM and see if there are any more to be had

I only glued the fully covered first foam wing into one of my RSTs...Yes I poked a bazillion holes for glue to grab. The other two have a fully covered wing held in place with ONE 24"x 1" strip of Gorilla tape outboard of Fuselage...you could also use reinforced strapping tape.... All my Fuselages have the BC under wing attached to the Fuselage

In all cases I set CG to be just a tad (1/16Th) in front of the spars (slightly nose heavy) and first flights were very mild and controllable... Only one of the three had a wing high issue trimmed with a Tab vs extra tip weight

I am a sport flier but a stunt buddy flew and trimmed my first one... some minor issues off the board... but he did fly the maiden with almost all the CPLA patterns ..not the full pattern... as we had no real idea on run time....insides and outsides were NOT same but close, inverted flight was very close lap time, just a tad of getting loose for overhead stuff .....

3rd flight after trim tab fiddling....he flew the full pattern with 2.5 Oz fuel and sent me home to build the other two...he has moved away but left me able to take three Beaters to the field and have fun for half a day---- with the only damage from my relearning stuff and nose planting occasionally... the original RST now has 2 oz more weight from Epoxy...Grin

BTW...followed Phil's wing prep For first wing set*... I have never broken the wing... always engine crutch nose area damage

* other two wings are actually tougher cuz I added Combat wing TE Kevlar cord and used strategically placed strapping tape ----instead of the multiple SLC strips as per the original RST instructions

BTW #2... I have nose planted, at full speed, both the built up Balsa fuselage copies and NOT broken the front like with the KIT Bass Wood Fuselage....... That said, I tend to think this may just be lucky from a angle of attack impact...Both were vertical 90 degree impacts and the nose break of the Kit fuselage was a 45~60 degree nose in

Anyway--- do NOT fret the small stuff..!!!

Get several more wing sets, if you do not have them, and each build will get faster and better...trust me

Phil sent me Nemesis and Ring Master Foam cores as well as several sets of the RST (Gottcha) cores... Profile fuselages and tail feathers are very easy to bash, copy, and have fun with

I am even contemplating bashing a (swap meet) damaged wing Giles 202 RC full fuse ARF into CL plane with a core set from Phil

Yes a solid foam core is heavier than the equivalent balsa built wing--- BUT so much faster to go play or experiment with with

Steve Schoenecker · « **Reply #8 on:** February 20, 2017, 08:38:17 AM »

Thanks for the info, Fred

I would love to see pictures of the gorilla tape wing mounting. I assume that allows it to separate cleanly without a lot of damage in a crash?

My bellcrank is on the top of the wing between 2 round plywood disks on top and bottom with a 1/2" dowel between them. Seems really strong. I attached an adjustable tip guide that allows up and down as well as fore and aft adjustment. Once I get it sorted out, I can make a simple tip guide to replace it and use the adjustable one on next airplane.

I do have 3 more sets of cores. I am waiting to see how this one works and balances etc.. whether I need to shorten the nose, tail etc for balance.. then we will build some more. I have a couple of fox .36x, a .35 combat special, another stunt fox .35... a Veco .45... some other .35s etc... Might try some of these on the next ones.. I am anxious to see how the clunk tank works. I've never used one on a CL airplane.

I have already learned a lot on this one... expecting to learn a lot more.. having fun anyway...

While waiting for paint to dry etc... I started working on a perky speed... have the wing built... noticed on the plans that there is no mention of where to put bellcrank?

I will figure something out.. the wing is pretty small to build there... I will look at under wing when I build Fuselage...

Pic is progress so far... wing just in fuse for fitting.. not glued in yet

Later

steve

Fredvon4 · « **Reply #9 on:** February 20, 2017, 09:47:34 AM »

Steve the RSTs differ a bit from your plane in that the Bell Crank is hung on a ply piece glassed to the bottom of the Bass wood or Balsa fuselage and the wing is free to be removed if necessary

I truly suck at some maneuvers/tricks as I re-learn how to fly. I crash at least once during every session... so Far, I have only ever broken off the noses and only slight crushing to the LE outer panel tip on one plane that got blown in on me and crashed nose and wing tip...

I am sure at combat speeds these wings may damage more --but for my 5.4 Sec laps on 60' lines and Small OS engines I have not yet managed to stress the wing enough to hurt one

One of the reasons for this is the added combat type construction I learned for foam wings.. Carbon TOE under the spars, Heavy Kevlar cord glued to the TE and around each wing tip to under a front LE spar (if there is one) or slightly recessed into the LE foam for a few inches. And instead of the Phil Cartier wing covering reinforcing using strips of SLC. I set several 18" long 1.5" or 2" wide strips of glass reinforced strapping tape slightly forward of the TE top and bottom.

IN a high speed nose plant, these reinforcements tend to prevent the wing from torquing forward against the narrow fuselage and spiting the wing in the middle

The RST wings I plug in and Tape with 1" wide strip of Gorilla tape -do eventually get messy from exhaust and is some what of a pain to remove the goo when I replace the tape...

None of these three are fancy pretty planes, although I did make one as a Ring Master (tail feathers, canopy) and spent a bit more time coloring the wing, fuselage, and canopy

john e. holliday · « **Reply #10 on:** February 20, 2017, 09:51:51 AM »

Don't know which plans you or if you are a member of the Brotherhood of the Ringmaster control line forum. Larry Marx has a post on there titled 'Perky 2.0 Project'. I have his plans and hope to build another one as the kit I built left a lot to be desired. Also a lot of info about the Perky over there.

Now back on line. Your plane is looking good and should get you ready for the built up kits. I have built several planes using Phil's core and his kit.

Avaiojet · « **Reply #11 on:** February 20, 2017, 12:45:32 PM »

Steve,

Nice looking model.

Charles

Fredvon4 · « **Reply #12 on:** February 20, 2017, 12:58:18 PM »

Charles in first OP post is the mention of Phil Cartier (Core House two piece Gotcha) wing cores

If I remember these are a 12" root x 6" tip, slightly swept back LE each panel 24 inches (for shipping reasons) so without added tips make into a 48 span wing of around 440ish SqIn

Steve Schoenecker · « **Reply #13 on:** February 20, 2017, 09:43:21 PM »

On the perky plans... I ordered the plans from the AMA plan service... I am trying to join the brotherhood of the ring...

On the stunt trainer... I built a few full fuselage airplanes years ago, when I was in High School. Lots of learning on this one, though... Surfed the "nose and tail moments" threads... Measured several sets of plans I have... Downloaded several more plans.... Picked a set of numbers,,,, copied some shapes... Started building.... I am anxious to see how the balance works out

Steve Schoenecker · « **Reply #14 on:** February 20, 2017, 09:46:48 PM »

The wingspan is just under 54 inches. ... I calculated the area to be somewhere around 530 sq. In.

Steve Schoenecker · « **Reply #15 on:** March 09, 2017, 09:33:19 PM »

Starting to come together. ... have to get pushrod set up & finish gluing the wing .... Oops... Tried to load a picture. ... Too big will have to do it later from computer

Author Topic: building with foam cores (Read 4211 times)

Steve Schoenecker

building with foam cores

Howard Rush

Re: building with foam cores

Tim Wescott

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Steven Kientz

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Steve Schoenecker

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Fredvon4

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Steve Schoenecker

Re: building with foam cores - Update

Fredvon4

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Steve Schoenecker

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Fredvon4

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john e. holliday

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Avaiojet

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Fredvon4

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Steve Schoenecker

Re: building with foam cores

Steve Schoenecker

Re: building with foam cores

Steve Schoenecker

Re: building with foam cores