Skyray Winter Project

[Mark Mc]

Well, for winter I’ve decided to follow the Brett Buck model and build three identical Skyrays to get through the learning curve.  I’m flying a Flite Streak Arf with a .25 FP , but I’m still leery of breaking the plane, so I don’t push it.  The Three-in-a-Box idea should hopefully break that fear.  I have the plans and enough materials to build three planes, but just the one .25 FP.  I could swap the engine between planes, but that doesn’t appeal to me. But, I do have three Fox .35s in the drawer, so I guess I’ll build three Fox powered planes.

I’ll build with full balsa ribs on a 2 ½” center.  2 ½” because it’s a convenient measure.  But I have two questions.  Brett recommends 3/32” ribs, but I’ve read somewhere that someone used 1/16” ribs.  With all full ribs instead of using false ribs, which would be better, 1/16” or 3/32”?  I have enough wood to do it either way.  Also, would there be any advantage/disadvantage to using a ½” center rib?  

I am also still debating the movable leadout guides.  I know Brett will say not necessary, and Tim will say do it anyway since I’m scratch building.  I guess I’ll figure it out when I get there.

Mark

[Air Ministry .]

2 mm !  ( Thats 5/64 th    )

1/16th would be a bit light , unless it FIRM wood .

YOU NEED THE ' NOSE RIBS ' Particularly at 2 1/2 spacing , unless your sheeting the leading edge .
And thatd sag , unless you formed it over a pvc drain pipe , before fitting . Pre Sanded'n all .

The Nose Ribs keep the AIRFOIL , in a Important part as regards producing LIFT , if your flying at Stunt Speeds . 4.5 - 5.5 Sec Lap .

The Ole Foxees , securely glue from spar fwd . A nose Doubler wouldnt hurt . 1/2 or 3/8 Sht. From Spar Fwd . Due to v v v vibra tion .

Drilling the Mounting  Holes 5/32 ( 4 mm ) if using 1/8 NF Bolts , should see ALL the Engines Fitting . FP 25 is within 1/2 Bolt of the Fox Dimns . If Im Not Mistaken .

In Centuries Past , building a wing ' by eye ' , in the hands ! a good twist @ the Tips , Ea Way the same amount - about ten degrees , before the glue kicked off
would have it set straight . IF you eyeballed down along it . You Twist to see it Sits Straight , so no stress is built in . Tho id take it youd build it on a flat bench with equal packers
under the spar or trailing edge . If not both  .

A trap for wary players , A Double sheet Trailing Edge , If you sit the top in the sun on the window sill or mantle piece over the fire , will shrink it .
So When its Glued On , as its humidity re equalises , youve got a Crescent Trailing Edge . Which is careless naughty & unacceptable .
So lay it somewhere adjacent to the THING where you ( and your wing ) are . NOT in ' another climate ' .

While were whingeing , Pre Block Sand flat things , Even Pre Dope a few cotes of lite coat pre fitting , standing em on edge to dry , unhuriedly .

Good Luck with the project . Economising by doing three simultaeneously makes sense . You Could try a few variations in tips & rudders , or trim . Or go for the Clone set up .As you please .

p s , you can even use TWO riblets between Ea Rib , fwd of the spar . They only need to be 3/16 or so deep . Top & Bottom . So Thats Four Between Ea . We trust youve cut a Rib Template ,
and tested it for symetry . 

[Mark Mc]

Also, another question.  What's the best way to make the bellcrank easily accessible after the wing is covered?  It seems like a good idea to me to be able to easily access the bellcrank for pushrod installation/adjustment and maintenance (if it survives that long).  I'd assume a hatch of some kind like on the Flite Streak ARF.  Just cut out a small square above the bellcrank pivot bolt and then make a lip around the hole beneath the wing sheeting for the hatch to screw down to?  Any thoughts?

Matt, with all the ribs being full ribs instead of half full ribs and half nose ribs, the nose thing should be well covered.  Measuring the plans as drawn, the full ribs are 4 5/8" apart, with 2 5/16" spacing between the false ribs and the full ribs.  At 2 1/2" spacing for full ribs, that's only 3/16" more space between nose ribs and 2 1/8" less space between the full ribs than per plans.  I'm satisfied.  But, if I get enough responses to do so, I guess I can put false ribs between the full ribs.  That'd put the nose rib spacing at 1 1/4".  I've just never been partial to the look of a bunch of false ribs on a wing.

Nose doublers will be as per plans, I think.  I thought about a tripler inboard, but I'll just keep it simple.  The name of the game is quick and emotional investment free.

Mark

[Air Ministry .]

the full ribs are 4 5/8" apart, with 2 5/16" spacing between the false ribs and the full ribs.  At 2 1/2" spacing for full ribs, that's only 3/16" more space between nose ribs and 2 1/8" less space between

if you have six apples & you take away four strawberrys , how many potatos do you have .?

Er Up . E=MC 2d etc. Right . A HALFD RIB is not a NOSE RIB , then , 

[Scott Richlen]

Mark:

You are over-thinking this process.  Just build the wing with whatever spacing.  It will fly good enough for climbing the learning curve.

And you shouldn't have to worry about bellcrank access if you install your pushrod correctly.

Just remind yourself that these are cannon-fodder: build, fly, try something new, crash, repair, repeat cycle...

Good Luck!
Scott

[Mike Griffin]

Hi Mark

Follow Brett's guidance.  He knows what he is talking about and has been doing this a long time.

Mike

[dave siegler]

I built 2 from plans out of balsa.  And you are overthinking it.  I didn't even measure, I just went over the plan.

3/32 ribs are a lot easier to build and cover and repair.    I wouldn't use 1/16 ribs unless I was going to sheet and cap strip the thing and don't bother.

I think I made the TE sheeting 1.5 inches, because I cut a 3" in half.

I shortened the nose a little too, just a little bit, it balanced better with the mufflers I had.

On the bell crank.  mount it solidly, attach the push rod and just sheet over it.  You should not need to get in there. 

On the engines, put the os on at least one of them. 

I have never seen 3 identical fox 35's.  They all vary a bit.  I love foxes, but on a profile, they can drive you nuts till you figure them out. 

If you have been successful running a fox on a profile disregard the above and use them.

I used a fox .25 on and an enya .19 on the other.  Both flew real well.  The enya one ran very well but needed a little shorter lines and was not a windy day airplane, but way fun. 

Bertt's advice is spot on, but you can move slightly off it. 

[Dan McEntee]

    On plans built Skyray .35s I used 3/16" balsa for the ribs. They were as light as the light ply ribs that came in the kit, and hold up well in crashes, which is one of your concerns. Just build it per the plans. And stick with your plan of using FP.25, even if you have to swap out the same engine. As much as I like the Fox .35, the nose of the Skyray isn't very stiff or substantial and it will act like a tuning fork with a fox .35 on it. Unless you add a full, 1/2" double to the nose to really help stiffen it up. Keep your eye out for FP-25s, they sold a ton or two of those and they are out there, be patient and look for deals. Check out your local R/C clubs for swap meets and maybe put a want add in their newsletters. I bought two almost brand new FP-.25s at the last swap meet here for 30 bucks for the pair. The guy selling them was clearing out, and the meet was shutting down, and he didn't want to take them home. Fly them with the throttles locked open or get some venturi/needle valve set ups from one of the vendors (I'm partial to Jim lee.) Again, I love the Fox.35 but in this case I think your purpose will be better served if you stick with the FP.25 plan.
  Good luck, have fun and HAPPY HOLIDAYS!!
   Dan McEntee

[john e. holliday]

Do as Dan says and send the Fox's to me.   Really Dan and Brett know what they are talking about.  Right now Fox 35's are getting some good money on the bay, but then I think some guys are helping bring the prices up.  Also Fox Mfg. has no more parts.  By the way post picture of what you are doing.

[Tim Wescott]

• Just use the FP and swap it around (or get more).  It doesn't take much effort, and I think you'll like it much better.  At the very least, make sure that you can swap the FP in after the fact.
• Use 3/32" balsa for the ribs -- 1/16" is too floppy, even if you're using light wood for the bigger ribs and heavier wood for the thinner ones