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Nov 08, 2005, 09:16 PM
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Excellent!


Nice job on the plane. I've been trying to decide what to build outta bluefoam to do some more AP, I think you've given me an answer.

I've been building mostly 'shocked' types of bluefoam 'champs'...and having a good time with em, but they're not really built for AP. This just may be an answer.

Any info/plans/hints for those of us with foam, time on our hands, and some exacto knives?

Steve
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Nov 08, 2005, 11:58 PM
Pull out early!
DiveBombDave's Avatar
Thread OP
Alright, that's two votes and that's enough for me. I find whatever build pics and take good clear pics of the sections, and discuss the build in a post for each major item (wing, tail, fuse, power). Keep your eye on this thread and I'll have them up asap.

I realized this whole design idea started around one thought, "I hate a prop saver." I had two planes nose in on take off from spitting the prop. So I vowed not to use them and went with collets.

On pullers, the hard-affixed prop would sheer motor and/or gearbox shafts at a scary rate. Testing new builds you always get a nose in or two until she's balanced. Pushers scared me at the time because of hand launching with power on and the 6000rpm 13" prop vs. finger challenge. So I went with High mounted pullers. Discovered the high mount tractor was too challenging to build a reliable mount where it wouldn't twist with power and be easy to ajust (AND they will break a shaft on a complete nose over, same prob again).

SO - Pusher with a fuse and tailstrut deep enough to offer plenty of peace of mind to handlaunch. This tailstrut is about 3" longer than the axle point against the fuse, and is rubber banded and skewered to allow some rearward flex (Yes, into the prop). It is very stiff and will only flex on botched landings, and I land deadstick anyway and rarely if ever ROG, though when it did I was listening for Brrrrrap when I pulled the stick back. The forward LG is conventional duralum and 3" dubros, bolt and nut axles. I've found that this extra weight is really nice to brace the fuse and campack in a crash landing, even if it rips clear it offers a ton of front end protection. The forward LG alone are maybe 60-75g, and provide a significant amount of forward balance considering how far forward they are. This is why I went this way instead of tricycle gear that you see on tons of pushers - I wanted all the forward CG I could get.

I haven't nicked a prop yet except one ludacris taxi on gravel broke a gb shaft. My only complaint is it's so overpowered sometimes my 70deg climb turns into a vertical climb and it's so high I don't notice, and then it either stalls or otherwise hammerhead turns to the ground at full tilt. By the time I noticed she was humming, and a sloppy elevator linkage almost made it go straight in. Since fixing the slop, she has done the hammerhead thing again but I was easily able to leave the power on and nose her right back up on low rates.

One more rule I have now is these wings must have a good spar. You never know when you will have a situation nose down and fast and you yank back and .... I'm getting a little shook up here.... you watch that 3lb load fold the wings up like a bad taco under the G's.... - I sawed a 10" tree down to get that one back. Had skewers as sparring. Ick. All birds since get full CF arrows, mated in the middle with the alum thread inserts epoxied in, and then a thick steel music wire hammered to about 12deg for dihedral. Only needs to be 3" long, and as thick as will fit all the way through the alum inserts. Epoxy 30min as much as you can get behind, around, etc the joint. Then a 6-7" CF arrow section is dremel drum sanded to mate to these inside the angle as well as possible. Draw the shallow triangle you've made on paper and reproduce in balsa sheet, 3 copies, one this size and two 1mm bigger all around. This 3 sheet triangle (oppose grains if possible) will have the smaller piece in the middle of the stack and created a nice channel to accept the rounded CF rod profile. Used epoxy to stick the short arrow ends down with triangle inserted, which by itself is silly and not strong but just locks it until you can - wrap the whole reinforced triangle with (I use) 50lb pure spectra fiber braided fishing line. I go heavy, since this is the real reinforcing strength, and then brush epoxy into the windings to keep anything from settling/slipping.

Alright, I'm getting into too much detail for this post, but I wanted to share the trails and pains I've gone through to get this design that I'll never ask any money for from anyone, which is the real beauty behind what we do - is WHY we do. Go ahead with any spec. questions so I'll make sure I cover them while getting something comprehensive together with the pics.

Oh, yeah, and rock on.

Dave
Last edited by DiveBombDave; Nov 10, 2005 at 03:39 PM. Reason: added spar pic
Nov 09, 2005, 12:02 AM
Flying on Flux Capacitors
Flipper_118's Avatar
Wow, this one has bit me good. Thinking I need to make this plane for my new AP platform. Love the pusher idea, and with the camera in the nose, makes it look like some sort of "spy plane". When my SS had a forward mounted camera it just didn't look right, and with a much smaller wing area, it came down like a rock without power. May build the nose much the same as yours with a little hole for the camera lens. Trying to cut down on the wind resistance. Thinking about ditchin the wheels, and just belly landing it, maybe a slider of sorts..........hmmm....................

Great idea with the rubber band hinges on the tail, make those 1 point landings a little easier on the frame. Going to be a sleepless night tonight.............

Love the plane, keep us updated on her.

Curt
Nov 09, 2005, 12:22 AM
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DiveBombDave's Avatar
Thread OP
Love the responses....!

Yeah, on the 'hole out the front' thing, there's a "Cover" or nosecone made out of FFF to slip over what you see in the above pic, and that's where the real strength is (I wouldn't fly without it), as the single FFF tongues that extend on the nose are very weak alone. The nosecover has a slot to afford the up/down tilt angles, and mine has a bunch more removed because of poor planning (shutter servo was restricting it with cover on). And she's a touch twisted, the epoxy on the the balsa tabs for the altoid's axle slipped on one side and I noticed 6 minutes later with 5 min epoxy.

Wait until you see it with the cover on... being 1/4" thicker, and rounded on the front, it looks like, well, you know. Phallic sp? "Penetrates the air well."

Had to say it.

Dave.

Hit a thermal a while ago from 200' went to this alt in under 60 secs. Any guesses on alt?
Nov 09, 2005, 01:29 AM
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DiveBombDave's Avatar
Thread OP
Here's the fuse template. It's 4" panels across the 23" FFF width. Tape outside of seams before folding, and it'll yield a 3.75" Inner diameter box. Cut some squares as bulkheads/formers, I only used one ply at the 45deg slope mid wing, two at the front of the wing with maybe a chopstick to chock the wing, and one in front and back of forward LG, and one just before the tongues (overkill maybe). I tried to crush this fuse design once for the trash can and it supported all my weight being compressed lengthwise. The top and bottom tongues can be removed (I did), but otherwise make a nice round blunted front end, not friendly to the rotation in my mind.

I'll post more pics later but this was the only one I have now.
Flipper - if you really are working on it tonight, congrats! I used the servos as 1/2" standoffs for the arrows, and across the 11" chord that made my 3degrees of wing incidence to the tail. I epoxied alum pop can tops broke in half to create forks, right to the servos. This locks the arrow and keeps it from wandering, then it's taped and banded. If I did it again, I would internalize these to the wing, somehow preserving that 3deg incidence. My wing is based on the selig 3021/Gentle Lady airfoil, maybe 1.5" thick. Just remember the whole idea is to keep everything but the batt on the wing, so fuses can be interchanged easily (grass pod, LG pod, "batt on a stick", etc).

The lines from left to right are CG, Wing front, and max forward LG (nose). All cuts are beveled 45deg with razor. Chopsticks for rubber band attachments. You will have to add a small strip to finish the sloped part.

Make sure you cut the wing saddle area down 1/2" in the rear at the points, so that the fuse points straight. If you don't the whole fuse bottom becomes wing pointed 3 deg up and needs more forward CG and pitches up with speed. BIG NOTE: I removed the portion that would contact the wing underside - a rectangle on the actual top panel, in the picture it's at the bottom panel from left side to the middle line. This flat panel would create probs with the wing dihedral, having to be lowered 1/2" in the back AND chocked along the lengths... just remove it, cut the wing saddle sides, and if you use a bulkhead underwing then cut a shallow V in the top of it. Whew.

Alright... I shoot pics and have them up in a couple of days at the latest.

Dave
Last edited by DiveBombDave; Nov 09, 2005 at 04:10 AM.
Nov 09, 2005, 03:55 AM
Ozzie Express wiggy pilot
SON OF PALEFACE's Avatar
Dave , exuse an ozzy , but wots, a ball and chain ???
also, how thick is fanfold ????
Nov 09, 2005, 04:22 AM
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DiveBombDave's Avatar
Thread OP
Flipper - see above BIG NOTE on fuse top.

Ozzy- Watch crocodile hunter all the time. Crickey.

"Ball and Chain" would be a standard reference to one's wife/girlfriend, obviously poking fun at the restrictions that relationships impose. Also, here in the states we like to refer to our partners derogatorily in the presence of our same sex peers.

I don't know why, but it's fun.

Fanfold I'm using is Dow BlueCor and is in the ballpark of 1/4"... it's a little off and I can't remember which way. I think I use .15g/sqinch for weight calcs. I multiply this by the bottom panel area, then by 2.1 for top panel being bigger and minimal internal ribbing. Adding CF arrow spars at 23g per pop, and I can get really close estimates before I build wings. This math is usually on the fat side for safety, too.

Over hear we have a cartoon called Southpark (for adults).... Cartman did a Crocodile Hunter ripoff where he would wrestle a croc and say in Aussie-speak, "and now I'm gonna put muh thumb in it's buh-ho.... crickey, he's angry now!" And this is all I can think when I see your Aussie speak posts.

Laugh.

Dave
Nov 09, 2005, 05:21 AM
Ozzie Express wiggy pilot
SON OF PALEFACE's Avatar
Yeah , unfortunatly , most non ozzies seem only to remember the "over the top" characters we produce from time to time , Paul Hogan in Crocadile Dundee and now STUPID Steve Irwin with his extremley exagerated ozzie accent and exclemations
We have South park here too and u either like it or HATE it
Because its sooo different to your way of life , it is attractive to most septic tanks (no offence intended) , oh well , its hard to please all the people all the time.
The reallity is we are very much alike , U just speak funny and drive on the wrong side of the road
Nov 09, 2005, 09:16 AM
Flying on Flux Capacitors
Flipper_118's Avatar
Well I won't be workin on the plane untill I pick up some FFF, but I ment that the plane would be playing around in my mind for the night.... which it was. I'm thinking I may have to increase the cord of the wing to get more lift since I want to have a wing that is bigger then my SS. Figure maybe 15" by 60 odd inches long. Still in the design stages. I only have my Nippy 1812 for a power plant so I need to try and keep the weight under 40oz. Should still fly well at that weight. Current SS weighs 32 oz and I have an 75 degree climbout.

Lookin to build more of a glider style plane for AP, instead of my Speedy slowstick. Need somthing that can actually glide.

Curt
Nov 09, 2005, 02:14 PM
Pull out early!
DiveBombDave's Avatar
Thread OP
Ozzy- Yeah, sorry about that comment, it was late and prolly wasn't well thought out. I agree paul hogan and steve irwin being what we see over here would be like you comparing us to Don Johnson of Maimi Vice or something. No offense intended Love to visit your country one day.

Flipper - Gotcha. Are you limited to 60"? I saw a SS with a 2m glider wing on it (too heavy for your power tho). I try to turn wing area into as much span as possible for roll stability - I think a 60x12 is as small an aspect I've flown on these, but with the dihedral it was absolutely fine. Turn on a dime too. I've flown several slightly different foils around this design, and no matter the wing shape as long as it's loaded at under 9oz/sqft it'll glide/thermal great. At 40oz that's 4.44sqft or 640 sqin, or 60x11 (Eleven inch foil is largest cut from single sheet of FFF, nice to conserve).

What's the loading on your SS?


Windy today..... very sad.

Dave
Nov 09, 2005, 02:41 PM
Ozzie Express wiggy pilot
SON OF PALEFACE's Avatar
Hey man no need to worry , I wasnt being critical of u at all , just explaining how it is
I might B touring your wonderfull country next spring
Nov 09, 2005, 03:57 PM
Flying on Flux Capacitors
Flipper_118's Avatar
My stick with stock wing has about 505square inches of wing and I'm hauling around 32 oz. Going to re-paint my stock wing tonight and replace the fuse with harwood, and bla bl bla. I have about a million different mods to do to it. I figure that if I want to increase my wing area enough to make a difference from the SS I will need so much wing, that I'll come in heavy, somewhere in the mid 40-50 range. That means I need a new motor, which also means I'm going to buy more then the motor if I venture into my hobby shop.

Curt
Nov 09, 2005, 06:46 PM
Pull out early!
DiveBombDave's Avatar
Thread OP
Paleface - Ah, "no worries, mate." Love to have you over here in the spring... chicks really dig the accent. We could go to the bars and put you on point, seek and destroy.

Flipper - You're loaded at about 9.14oz/ft2, so it seems it should glide OK, but you SS guys know the way that wing flies. I have motocalc if you have your motor specs - do you know the static thrust you're getting? I had an axi with 900g thrust that hauled up a 48oz beast for 100's of hours. Climb was respectable at 30deg and maybe 400-500fpm. This same plane I could "stall it down" with a little up elevator, it would come down like a real elevator. Maybe if you're trimmed for powered flight, when you cut the throttle try a few clicks of down trim and see if the speed up will help your glide angle/ratio. In other words, experiment with different elevator trims when gliding and see if you can get a little more outta your SS.

My wing is 70x11 and AUW is in the 45oz range with 8.2oz cam bundle and maybe 3 oz in forward LG alone. And the metal planetary I have runs my motor, prop, and ESC weight up to 230g, or about 8 oz, where your nippy is lighter. Just in motor system and LG this design seems like it could be done the same size at 40oz auw.

Of course not telling you what to do, just very passionate about my build and trying to help you with the stuff I've been through. Lemme know what you decide!

Dave
Nov 09, 2005, 07:49 PM
Flying on Flux Capacitors
Flipper_118's Avatar
DiveBombDave,
Don't worry, I don't feel as though your telling me what to do, I need all the info I can draw out of you. I getting the FFF in about a week (ordered, not at my HomeDepot) so I will start building then. I think I will crunch some numbers as to the amount of foam I will need, the weight and then see how it compares to the SS airframe.

I read under the heaviest SS thread that DepDog was flying the stick at 40oz! I figure if I sacrifice a little climb, I can fly a 40-maybe 50 oz model. Lets see 11 volts with 18 amps WOT, that gives about 200watts, lets take about 50watts per 16oz, that equates to a rough absolute AUW of about 64oz! But thats only theoretical not actual. Supper time so I'll measure the thrust I get out of my Nippy after feeding.

Curt
Last edited by Flipper_118; Nov 09, 2005 at 08:08 PM.
Nov 09, 2005, 08:07 PM
Flying on Flux Capacitors
Flipper_118's Avatar
Alright slammed down the grub and got back to important things. I put my SS on the floor and held the digital scale against the horizontal stab. At WOT it was buzzing and the scale read 29.8 to 30.0 oz of wind! Would have filmed the test, but is scary enough running my Nippy fully ramped up with only a small horizontal stab to hold it back! So may have enough power if I keep the weight low. Going to have to go raid Wall-Mart for some carbon arrows......

Curt


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