Skyray questions

[James D. Hayes]

I usually come on here and read but I don't post very often. I've been building and flying control line around 3 years mostly flying Ringmaster's and the like. I have just started a Skyray .35 and I'm using Brett's suggestion's and write up's on the build, engine setup (.25 FP) and so on. I have a question. I ordered a 3oz. Hayes fuel tank that will be setup for uniflow. How does it sit on the airplane. These tanks have that funny side that is longer. If anyone has a picture of the correct way to set one up I would appreciate seeing it. Do I want a adjustable leadout or fixed. Lastly, I'm curious why there is no engine or rudder offset.

Thanks,
Jim Hayes
AMA 988835

[Gerald Arana]

Jim,

Funny side goes down.

On mine I added a tapered fixed flap and about 2-1/2" tips. I also enlarged the stab/elev. 1-1/2" (3" total) and it flew great. That was before the up line caught on the down line handle connector-pilot error- and it ended up vertical on the unintended landing!

The flap was 1-1/2" root and 1/2" at the tip.

Good luck, Jerry

[Tim Wescott]

I usually come on here and read but I don't post very often. I've been building and flying control line around 3 years mostly flying Ringmaster's and the like. I have just started a Skyray .35 and I'm using Brett's suggestion's and write up's on the build, engine setup (.25 FP) and so on. I have a question. I ordered a 3oz. Hayes fuel tank that will be setup for uniflow. How does it sit on the airplane. These tanks have that funny side that is longer. If anyone has a picture of the correct way to set one up I would appreciate seeing it.

I don't know how you're going to get a Hayes tank set up for uniflow, because of the way the spigots are arranged.  You don't need it for an FP 20, but I dunno about an FP 25.

I lay my Hayes tanks flat, with the long thingie (the sump?) down.

Do I want a adjustable leadout or fixed.

with edits

Brett will tell you to just put the leadouts on the plan location locate the leadouts per Line III (I think -- see his response below).  Leadout position is much less critical when you don't have flaps, and figuring out the best leadout position can get confusing.  I think that you may as well make them adjustable while you're in the bare wood stage, but start with them in the plans location.

Lastly, I'm curious why there is no engine or rudder offset.

Because you don't need it!!!

Rudder offset just isn't used any more, except for some really expert folks who use Rabe rudder.  You may benefit from a very slight engine offset (like, 2 degrees out), but beyond that -- you don't need it.

[wwwarbird]

 If it's a properly set up clunk tank it shouldn't matter which way the funny side faces. In flight the fuel is going to end up at the outside rear of any tank you use. In this case I'd set the funny side against the fuse, simply for cosmetic reasons.

[Brett Buck]

I usually come on here and read but I don't post very often. I've been building and flying control line around 3 years mostly flying Ringmaster's and the like. I have just started a Skyray .35 and I'm using Brett's suggestion's and write up's on the build, engine setup (.25 FP) and so on. I have a question. I ordered a 3oz. Hayes fuel tank that will be setup for uniflow. How does it sit on the airplane. These tanks have that funny side that is longer. If anyone has a picture of the correct way to set one up I would appreciate seeing it. Do I want a adjustable leadout or fixed. Lastly, I'm curious why there is no engine or rudder offset.

Thanks,
Jim Hayes
AMA 988835

   Here is my Skyray trim setup. The leadouts are well ahead of where the plans show, but my CG is far ahead of the plans location, too.

http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=198043&mesg_id=198043


  This is one of many on the topic of rudder effects:

http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=2609&mesg_id=2609&listing_type=search#2612
   Brett

[Tim Wescott]

   Here is my Skyray trim setup. The leadouts are well ahead of where the plans show, but my CG is far ahead of the plans location, too.

Whoops.  I misquoted Brett.  Sorry.

[Jerry Olson]

This is a photo of my Tomahawk but since the question was about the set up for a Hayes clunk tank it may help.  The engine is an OS 25LAS.  It is not set up as  uniflow, just a regular clunk tank with muffler pressure.  This set up works well for me.

[Perry Rose]

If you really want to make the Hayse tank uni flow you need to poke an 1/8" tube through the front wall in the center of the vertical face. I use an 1/8" awl to make the hole and quickly remove the awl and insert the tube. A bit of a bend in the tube will give you adjustability. I have trouble posting pictures but I'll get one on someplace.

[Perry Rose]

And again.
 I did it. Finally. 1000kb total is the trick. The dark spot in the side of the tank is the end of the tube. No sealant is needed as the plastic closes around the tube and seals it tightly. The seal also holds the tube in position. I use this on any plastic tank I want to make uni flow. It works just as good for pressure.

[Gerald Arana]

Pete R.,

Thank you for posting that photo.   I was wondering how I was going to do the same thing..........

Years ago there was a system where you poked a large (3/8" maybe) hole and used a rubber stopper like the supply line and I used to have that system but I think I threw it out years and years ago........Drat! That is why I never (well hardly ever) throw anything out!

Cheers, Jerry

[dirty dan]

If it makes you feel better perform mods to make Hayes 3-ounce tank a uni-flo breather. I've done it (twice) and see no benefit. At least not with a 20FP and BB-TU (read: stock).

Of more use is to kick rear of tank to outside of circle. A mere 1/8" shim is all that is required; some use more.

That odd shape of tank will require mounting it a little higher than centerline of engine. So err on too-high during initial setup.

 Using a stock tank, if you kick rear end out and don't muck up the feed line you're looking for clean and consistent run with an abrupt cut-off. If you want some warning shorten feed line in small increments.

Dan
 

[Steve Helmick]

I seem to recall seeing Dirt using one of these tanks kicked over, with the "top" tube becoming the uniflow and "foot" against the fuselage?  I contemplated doing this when I put a Hayes tank on the blue meanie, but decided it would be a PITB to fill with fuel (hold plane with inboard tip down). It ran well without uniflow, but I never could figure out a cure for the windup in the round outside loops. Everything else was good enuf, ...as long as the tacho was used to set launch rpm...  Steve

[James D. Hayes]

Thanks everyone for your input on the tank. I think I will stick with the normal non uniflow setup with pressure. I will attempt to shim the rear portion of the tank out a bit and mount the tank slightly above centerline with the engine and go from there.

Jim Hayes

[Randy Cuberly]

I seem to recall seeing Dirt using one of these tanks kicked over, with the "top" tube becoming the uniflow and "foot" against the fuselage?  I contemplated doing this when I put a Hayes tank on the blue meanie, but decided it would be a PITB to fill with fuel (hold plane with inboard tip down). It ran well without uniflow, but I never could figure out a cure for the windup in the round outside loops. Everything else was good enuf, ...as long as the tacho was used to set launch rpm...  Steve

The cure is Uniflo!!!

Randy Cuberly

[Steve Helmick]

The cure is Uniflo!!!

Randy Cuberly

My cure was to give it to Tim, complete with lines, handle spacing, launch rpm, and starting procedure. That pretty much took care of the problem, in a terminal sort of way.  Steve

[Tim Wescott]

My cure was to give it to Tim, complete with lines, handle spacing, launch rpm, and starting procedure. That pretty much took care of the problem, in a terminal sort of way.  Steve

OTOH, that was the last time that I've crashed an airplane, or close to it.  Sister Jenny was not expected to last out a year, much less be my ride for two years in a row.

[dirty dan]

I seem to recall seeing Dirt using one of these tanks kicked over, with the "top" tube becoming the uniflow and "foot" against the fuselage?  I contemplated doing this when I put a Hayes tank on the blue meanie, but decided it would be a PITB to fill with fuel (hold plane with inboard tip down). It ran well without uniflow, but I never could figure out a cure for the windup in the round outside loops. Everything else was good enuf, ...as long as the tacho was used to set launch rpm...  Steve

Close, real close. But different models, different tanks. Still (pukey) profiles however.

Models are of  Wimpact series developed by Derek Moran and myself. Tanks used are the Hayes Slimline 4-oz and (sometimes) the 6-oz number. Models are powered by piped O.S. 25FPs. MACS aluminum pipes are preferred. No pipe pressure. APC 10-3 props. Largest of my three models is 450 square inches and they are merely scaled Impacts then converted to profile configuration.

As to the tanks used, Steve is right in that they are laid on their side with vents to right of model. Of course this mildly complicates fueling procedure but raising nose of model takes care of the issue.

As the tanks work superbly this is not anything of consequence. How superbly? Don't believe me. We were flying in Salem, none other than Don McClave was one of the judges. As the model landed Don couldn't wait, actually coming into the circle as we were removing the model. "That thing runs exactly the same for the whole flight! What tank are you using?" While initially he didn't seem to believe it was an RC clunker it wasn't long before he was experimenting with similar setups. (Don had always been a hard-core fan of metal tanks.)

Dan