critterhunter

Nice plane!

critterhunter

A friend came over a few nights ago and we did some more foam cutting in the garage. He also showed me how to re-wind a BP21, which I'm still in the process of winding for lower k/v, higher torque to go on my Cessna build.

I finally got around to testing the wing fix for the huge dual boomer to see if the flex is gone...And it works! Originaly I had two aluminum arrow shafts glued into the two wing sections that would sleeve over the fiberglass rods I also have glued (full length into the wings). The two wing halfs would come together and the fiberglass rods would slide into the aluminum tubes. The wing sections would then be bolted to the fuse via four nylon bolts, plywood on top of the wing, and basswood glued to the top of the fuse tapped for the bolts to thread into. The booms also bolt to the wing via plywood/basswood and two nylon bolts per boom. There was too much forward/backward flex of the wing with this setup.

So, I removed the aluminum shafts and cut new ones that were long enough to reach just past the booms. That way they'd we sandwhiched between the bass/ply on them just like they are on the fuse. I then added to more aluminum tubes further back on the wing to also do the same thing, though they don't have anything sleeved into them (yet). Bolted the bird back together and the wing and booms are rock solid! They'll get even stiffer once I put some Extreme strapping tape over the tube channels and such. Very happy this bird is going to be possible, 6 foot wingspan and all. Will throw some pictures up this week of the wing strength mods.

Since this is going to be my AP plane and I've had three camera setups collecting dust for a couple of years now, I'm very anxious to get it into the sky.

critterhunter

A friend motivated me to fix the Mustang (brought it in still non-working order) and got that into the air for a minute or two. The wing had no "traction" and I think it was due to COG or the motor thrust angle. Killed the throttle and tried to land but it stalled. Broke clean up front and should be easy to fix. This time I'm putting a carbon tube nose to tail in it. The front end is just too weak due to the battery compartment and it will snap on any nose in. Luckily the prop saver he threw on there saved the shaft and prop.

critterhunter

Here's a few pictures of the big dual boomer with the 6 foot span along with the wing mod. It's a little hard to see it but there are four aluminum tubes glued into each wing half (2 per half), two of which have a fiberglass rod that slides into them as the wing slides together. The fiberglas rods are glued the full length of each wing section and stick out a good 7 or 8 inches to slide into the aluminum arrow shafts. The back two arrow shafts may also get fiberglass rods to slide into them that will be full wing length, though at this time it's plenty stiff enough...even without the Extreme strapping tape I plan to cover the channels with, not to mention the Extreme tape I'll use to hold the tempered dihedral I'll be putting in the wing for stability.

The basswood glued to the top of the fuse/booms along with the plywood on top of the wings that the nylon bolts go through really helps to sandwhich and hold the tubes/wing as "one". The one piece plywood section that goes on top to join the two wing halves will remain unglued (of course), but the two pieces of ply for the booms are going to get glued to the top of the wings for even more strength. Took a lot of head scratching but I am real happy with figuring out this simple mod to join this wing. The booms don't currently have any carbon or tubes in them yet they are very strong with not much flex if you push down near the tail. I was worried this would still tork the wing. I'll either add carbon or glass tubes inside the booms or just rely on Extreme strapping tape to make sure they stay stiff. Might have to order my Hextronicks 35/36 1100 k/v motor pretty soon for this bird. Anybody have an opinion on the two servos (one for the two rudders, one for the elevator)? I was thinking HS81 non-MG versions but perhaps I should go bigger?

Excuse the dirty look of the foam along with a few odd chunks taken out of it. Dirt is from the floor, dings are from a curious nephew. Nothing the paint and tape isn't going to hide. The clear tape on the wing was just to keep the gorilla glue from escaping foam and will be taken off later.

critterhunter

As promised, here's the new motor mounting method I'm using with some thin (but strong) aluminum. Notice the melted foam on the front of the Cessna's left/right and front side to allow the aluminum to sit flush with the foam for better looks. Also notice the holes drilled into the aluminum. This will allow you to use a nylon bolt/nut to adjust the motor thrust angle if need be. I, however, just have a carbon tube glued through the fuse that is just long enough to stick through the drilled holds, insuring that the aluminum won't pull free from the fuse. The carbon and aluminum will get a healthy dose of gorilla glue to make them "one" with the body. I had to remove this mount once already and that is why the foam looks a little rough where the mount goes. The motor's mounting plate is just screwed to the aluminum. This can be done with sheet metal screws (drill out the motor's plate holes so you can use a bit larger screws), and this provides for easy plate removal without the need to access the back of the mount. However, if you do use nuts and bolts there is enough room to put some needle nose plyers between the foam/aluminum and hold the nuts while you unscrew the bolts. With either method, make sure you dab some locktite, nail polish, or some other glue on the screws or bolts and nuts to prevent them from vibraiting loose. Really, the gorilla glue you should have behind the aluminum in the front as well to glue it to the foam should foam out and cover the nuts or screws. The picture looks funny because I have the plane sitting sideways somewhat, but the mount slides over the left/right sides of the fuse. A nose cone will hide the motor/mount.

vtrc

Sorry -- been away for awhile doing chores and jobs now that there's warm weather.

Nice plane Saucerguy! Really glad to see another new SO style plane flies.

Since the full ailerons seem to cross the booms inb the picture, there must be some vertical space between the boom and the aileron -- as a guess?

Just read an article about wing tiplets -- how do you feel they affect the plane, in your experience, compared with your old SO?


I hope the SO style planes keep coming in this thread, even though it's open to other types.

I'm sure I'll build another SO some time -- my current one is getting too easy and predictable to fly -- I get a little bored now! Probably time to take on the challenge of an aileron and straight wing. Get back on that horse, after Popeye bit the dust.

Did spin in my J3 -- though a tree saved it from damage. Needed tons of right trim -- the engine thrust needed more right.

It is much more control sensitive and "flitty" in any wind at all. Kinda like it, but don't trust it -- kinda unpredictable except in an absolutely flat calm. The SO on the other hand can handle a bit of wind. The J3 folded its wings early on in one gust that flipped it vertical, then sent it into a dive. Have strengthened it since with no further problems.

My SO slowly loops after a dive -- and tries to roll out. It just wants to fly itself in a normal posture if given half a chance -- which is fine for a primary trainer. On the other hand The J3 will loop pretty fast. But you also have to do a fair amount of work recovering from it. I think the big difference is the single sheet undercambered wing vs the solid foam Clark Y of the SO. It's like difference between a yippie little pedigree dog vs. a solid calm working dog.

I have a feeling the J3 might need a little more tail surface -- keeping the maneuverability, but easing the recovery.

I think at this point I like a solid foam wing better than a undercambered sheet wing -- I like the stiffness and toughness, and predictability.

critterhunter

Did you email me this yet?

critterhunter

Just a quick thought on building these foam planes, which I know has been covered before but is worth mentioning...Whenever you are building a plane, more importantly a new design that you don't have experience with, it's always a good idea to leave way too much nose length on until you've got the entire plane built with electronics installed and are ready to place the battery on top of the fuse to determine where it needs to go inside the foam. After that's been figured out simply cut and sand the nose down to the desired length. As you can tell by my Cessna screwup a page or two back, I should have followed this rule myself. The big dual boomer might also bite me for not doing this. Then again, on that plane the fuse is removable so I'll just hot wire out a new one should I need a longer nose for proper center of gravity with the battery.

critterhunter

Got the file in Email and already printed the tiles out. Thanks once more! Nice job...

vtrc

And, if worst came to worst and the fuselage was both shaped and glued to the wing, yet the CG needed to be moved forward, you can just chop off the nose square and hotglue on a longer blank of foam, and re-shape. Probably all of 15 minutes work.

I like to push a bamboo skewer right through the fuselage lengthwise as reinforcement. Acvtually a couple of them, one from the top and one from the bottom of the fuselage, starting a little ahead of the wing and angling up or down slightly, so they form an X inside the fuselage. They are easy to push in, being pointed at one end. They are invisible, since they go all the way in.

These prevent the usual fuselage nose breakoff if you hit it hard.

The same thing can be done with the booms starting somewhat ahead of the trailing edge on the wing, and inserting on a shallow diagonal into the boom --lengthwise.

The two main places I have had breaks in the past are reinforced this way -- fuselage at the wing, and boom at the wing.

saucerguy

Thanks for the compliments on the plane, yeah, there is a gap for the ailerons, I used a piece from the original scrap on the wing for a perfect fit in that area. I'm actually only using strapping tape on the fuse and covered it over with the Zagi tape, it's surprizingly durable. The wingtips which were designed for it in flying wing style have shown merit, it doesn't lose altitude in tight turns because of them being there so might be something you want to try out.

Looking good on the progress with your's critter, I can't wait to see it complete, this is becoming a much more sophisticated of a plane with all of the differences and revisions we all have done to it, it shows it's versatility, ie. you can do it quick and dirty per the original plans, or you can do alot more with it and it's still proving to accept the revisions.

Vt, sounds like it's time for you to make some larger ailerons, this will make it much more of a handfull and will push your skills forward. After retiring the beast, I am a better pilot for it since I went overkill with those and the power system. Luckily the only thing I retired with it permenantly is the fuse, I rebuilt it 3 times, the wing is slated for a future build, or I may retrofit it onto another fuse I have laying around. I retired it to put the power system into the latest saucer, which maidened and is getting some beefing up in the nose section for added weight and strength since no amount of trim was allowing me to compensate; Saucers in general require a little more in that area then regular planes.

Along the fuse pre-configuration with new so designs, Critter, you are right, I didn't follow that rule with the latest one so the battery pack is as far forward as possible and I still have to dial in a decent amount of down trim. After adding the nose cone and canopy, I'm digging the jet looking appearance it has, I may even mount a camera onto it since the added weight there will not be a factor.

VT, I actually had a chance to give fiberglassing advice to a guy that's fixing his ultralight. It was funny since he posted a thread asking for advice on fixing carbon fiber, and it wasn't until later at the watt flyer live chat, where he admitted it was for a full size plane, I had to give a whole new set of procedures in that case since fiberglassing these little RC planes, you follow different techniques compared to something to scale. I forgot to mention that he should talk to you as well, he was actually concerned that he'd get in trouble for not being an RC-er, which we know, would never happen, just make sure there is clarification about questions like that or you are not going to get the proper advice, ie. rc style verses full scale are two different animals.

Also, when everything is said and done, with the number of planes I have, all of varying styles and quality, my favorites remain the ones based upon the So. platform and I always bring at least one out to the field knowing old reliable will never let me down.

vtrc

Actually Saucerguy, I haven't had ailerons at all, since Popeye, just the single rudder on my trainer version SO -- and the J3 is 3 channel as well.

So I think it's probably time to get a fourth servo and build a new SO. I do want to keep the rudder, to ease on into the transition.

I had a chance to demonstrate flying RC to friends with a little boy over the weekend. Chose the SO over the J3 because of the predictability and the fact that it was hot and windy that day. Waited until near dusk, but still some wind. The plane would make a little headway for awhile under full throttle, then I'd turn it and dart back in the downwind circle and start all over again. Never got enough altitude to try a loop before using up the battery. Brought it in with a final into the wind and it did land well.

But they were all thrilled especially the son -- even though my performance was not exactly awe inspiring to me.

Anyway, the SO and variations is a kind of known quantity that you can depend on, even if conditions aren't perfect -- definitely a plane of choice.

Good reinforcement if you crash another plane, I found, too, when the J3 wing broke. Switching back to the the old faithful SO after losing the the J3, things were put in back in perspective.

vtrc

I'm afraid I couldn't help there -- I've never used CF, though owned a reel of CF unidirectional tow for boat use in the late 70's. Just never used it -- sat on the shelf for years while I was buiulding boats.

There are lots of books on aircraft composite construction so maybe he should look at those. Repair is a lot trickier than original composite construction, especially with a real plane at stake -- all kinds of considerations like stress risers, and thickness changes, stiffness transitions. Maybe consult his local EAA chapter people for help on composite construction.

My Heath Parasol replica is traditional construction -- fabric over wood. And my old Wizard was aluminum tube and dacron sailcloth type. No CF needed for either. When a tube broke or bent, you just replaced it. Didn't try to patch it.

So, wish I could help, but not qualified.

saucerguy

Luckily I've used fiberglass extensively, not on RC, but on Yachts, so even if he brought it into a shop, he'd know exactly what to look for in their technique. The repair was not for a structural element, I did tell him to replace the carbon stock in the first place, but he didn't want to, so opted to go with the fiberglass repair meathod. Luckily I was able to give him advice on it from my own background, RC fiberglass repair would have made it too weak.

When you go to ailerons, it's going to be an all new plane for you, it will be much more of a handful and should challenge you for a while. Before I moved up to those, I was doing things on the 3 channel bird I'm not supposed to, this helped with the transition since the response time will be necessary to increase due to the new control.

I know what you mean along spectators, especially kids, they just love seeing the plane fly. Sometimes I get people that want me to do crazy stuff with mine, I typically don't per request and not having rudder control in most of my planes does limit what can be done manuever wise, so don't sweat the showing off factor, it's not their expensive gear flying around the air.

critterhunter

More progress and pictures on the "BIG'N" dual boomer...

I was so happy with the wing strength mod, even though the tail seemed plenty stiff enough, that I decided to go all out on them too with carbon. I figure, why not build a tank like a tank? There shouldn't be anymore worries of body/boom/wing flex now...

In a few of these pictures, you can get a better idea of the wing strength mod. I also have the ply glued on top of the wing now. The middle square of ply that joins the two wings is glued to one of them for an added touch of strength.

I did have a flat piece of carbon on the horizontal stab but wasn't happy with that, so I took that off and inserted two carbon tubes through the coruplast near the leading and trailing edges with some gorilla glue. I had a great idea for these. I was going to heat the coruplast with a heat gun to allow me to push the tubes through the channels without having to slit it. It was working but I quickly realized I'd need an extra set of hands, so I just slit a channel.

The carbon tubes in the booms are being inserted under the basswood a good few inches, so they will be "one" with it once the gorilla glue is used. The two tubes in the h-stab cross over the tail boom tubes and will be glued as well to form a kind of skeleton.

She should hold up to some pretty rough landings, which I never have of course...

critterhunter

The last three photos...

critterhunter

You guys are right about the "So" making a great platform to build in just about any way, shape, or configuration you can think of. It's a very good plane to learn on, build with more advanced flight abilities, and not to mention it's such an easy design to build. Who knows where this platform will take us in the future as ideas evolve. I still haven't glued up my tiny version with Aero Ace guts in it to test fly. Should do that soon since it will take all of about an hour to complete. As said before, a friend is building a version of this plane with the body reversed. The horizontal stab will be in the front and the wing in the back. When he finishes it I'll post some photos.

Sooner or later I'm going to build a version of FoamFlyers "Skitzoprania", which I think looks really nice. Reminds me of a Warthog somewhat.

vtrc

Yeah and I'm probably never going to be happy until I can build and fly a Gee Bee Z replica.

Actually I'm sure I can build one. . . .

It's probably good that I can't fly one, because I'd probably then have reached my goal -- and then what do you do?

critterhunter

You guys have got to check out this thread on hotwiring out scratchbuilt foam planes. This guy makes me feel like I've been working with sticks and stones. Printed it out so I can read and learn.

http://www.rcgroups.com/forums/showthread.php?t=93759

vtrc

Great link, Critterhunter!

I picked up one very interesting bit, besides -- did you notice he recommended 1.5 pound per cubic foot EPS foam over 1 pound stuff?

I suspected, but didn't know for sure, that white beaded EPS foam could vary. This confirms it.

It may explain why I had so much sag in my wings on Popeye -- the foam I used was not the Home Depot stuff, but salvaged foam from a refrigerator truck.

I don't know how many pounds per cubic foot it is -- suppose I could measure it. But it does tell me that not all white EPS beadboard is the same.

I used the same foam on my second SO trainer, but I reinforced it with bamboo skewers, while maintaining a light AUW. If I was working with 1 pound EPS, this would all make sense -- low weight even with required skewers.

It's possible that others have had a stiffer foam, and so didn't need stiffening as much as my plane did.

It didn't make sense really that all white stuff was the same -- different manufacturers, different parts of the country, different insulation requirements, etc.

Now it would be good to understand what's available, and how to use it best.

saucerguy

Good job on showing us how you are doing on the tank critter, she's going to handle some serious abuse. The hotwire can indeed build the entire plane, it's just a matter of breaking it down into smaller pieces as that rcg build shows. I'm going to eventually set up a diy cnc system and will be going that route so there will be no need to manually cut anything.

vt, you are correct, there are a myriad of different types of epp, eps, or any other type of foam, part of it is the chemical composition, part of it is how it's processed and the supplyers typically custom tailor each to the clients particular application. In the future, I'm going to attempt to take the raw epp pellets and process them here into expanded epp in order to get the costs down on that stuff, just got to research more upon exactly how the commercial extruders/expanders are set up in the first place.

critterhunter

Yea, I noticed the weight difference he mentioned.

By the way, how do you guys like my "MASTER OF THE OBVIOUS" avatar? Fits me perfectly...

critterhunter

Here's a thread on testing of the Hextronicks motor I plan on putting on the Big'N. Follow the links there as well as it makes for some interesting reading. Can't beat it for a $25 motor...

http://www.rcgroups.com/forums/showthread.php?t=666418

Anybody heard from Fisher or Ken lately? Hope they are alright...

saucerguy

Nice avatar, I'm thinking about making a new one for myself, sick of the one I use at WF, but they kind of stick with you.

I think they are on vacation for a while, Ken and Fisher, we've had other members stick around long enough to become part of our little gang, vt is the new addition, so far it's a band of 4 brothers here, but all who posted before are perfectly welcome to join in.

I took super so out on it's third outing, burned through 4 packs and everything went flawlessly. I even landed down wind due to the stability, it's nice once the trim is dialed in, you just point it to where you want it to go and let go of the sticks, even in the constant winds I deal with, only minor correction was made and only for a few brief moments. After gliding it around, I'm thinking about using those wingtips to further advantage by using them as a mounting platform for removable wing extensions, this way I can really slope around in the sky with it should I want to go for endurance. It does glide well regardless on it's own, but is one of those mid range types of formats so is not the fastest, nor the slowest. Going the other direction would just mean a lipo upgrade, I'm only using 11.1 1000 mah packs on it and the motor of which could be upgraded can handle more, the current one is just a little warm for me after a run so I'm not going to push it.

critterhunter

Here's the completed fins/rudders for the "Big'N" dual boomer. I went a little carbon crazy but, hey, it's a big plane and it deserves big strength mods. I used flat carbon stock and just grooved the Cell Foam 88 so the material would sit flush with the foam. The widest flat carbon on the rudder is where I plan to mount the control horn for max strength, though it's a bit further away from the leading edge than I wanted. Couldn't get any closer because my heavy duty dubro hinges are already sunk there. I'll probably also still tape over the entire fin/rudder surface areas for added strength and to smooth airflow over the hinge point. Notice I have the carbon sticking down far enough to gorilla glue into the booms, and I also used a few more toothpicks to join the fins to the booms even better. A friend told me to cut the rudders with the up angle to help with turns. Guess the logic is it helps to dip the wing into the turn rather that fish tail it?