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phoenix decathlon

Old 04-22-2007, 07:52 AM
  #176  
IronCross
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Default RE: phoenix decathlon

What John said...
I am using Futaba servoes and added 6 inch extensions to mine..
Ad for the gyro, I have a couple of Extra's, 3 Mustangs etc .. They are all tail draggers and no problems getting them to track straight on take off.. I had a Global Decathlon that tracked straight down the runway... The Seagull especially and the Pheonix to a lessor degree seem to be a whole different story.. .. On John's advice I put a gryo in my second one and it made it a much more enjoyable experiance for me..
If I remember correctly the engine measurment on mine is 4 1/2 inches... .. My battery ended up 3 or 4 inches back behind the wing...
John..
Have you flown yours yet ?...
Don't know about Az but the weather here has been terriable for the last couple weeks.. Up to 40 mph winds and raining today... Not Dec weather
Old 04-22-2007, 09:37 AM
  #177  
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Default RE: phoenix decathlon

IC...no maiden yet but close. Been working on J3 and other issues. Sorry you missed the 1/8th AF meet. Good turnout and beat the weather on Sat. Been poor here in the valley, unpredictable, not what we are used to with winds etc. I forget where you are other than Nearby, AZ. Soon we will be fighting the heat!

John
Old 04-24-2007, 03:07 PM
  #178  
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Default RE: phoenix decathlon

Well here are some pictures I took two weekends ago. Next time I will more detailed pictures. The screws that hold the wing strut came off from vibrations and I just replaced them with cable ties. I will change this back to screws but will put a nylon nut or loctite them. How do i upload pictures? could not find any buttom for it.
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Old 04-25-2007, 08:06 PM
  #179  
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Default RE: phoenix decathlon

Sorry to keep asking questions but.... How did most of you guys run the exhaust with a four stroke on the factory mount? I was thinking about putting it in the cutout section behind the cowl and using a diverter to get the exhaust to go straight out the bottom of the fuse. Trying not to cut the cowl up anymore than I have to.
Old 04-25-2007, 09:06 PM
  #180  
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Default RE: phoenix decathlon

Jason,

I'm using an extension out under the fuse. It is from Hobbico. Gray silicone and comes with two plastic ties. Works good but they have a tendency to fall off. Perhaps a wire wrap might be better but I haven't tried it yet...$3.00 ! You might want to consider painting that area for a little better fuel proofing.

John
Old 04-25-2007, 09:08 PM
  #181  
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Default RE: phoenix decathlon

I ran the exhaust on both the .56 and .72 right into the cutout... No deflectors or anything used... The clearance on mine is more the adequate .... No problems at all... I did also however cut a hole in the bottom om my cowling for cooling and to allow me access to the LS needle on the carb... Whole thing works great....
Sargento
Great looking SDC there... Your in for a lot of fun flying
Old 04-25-2007, 10:39 PM
  #182  
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Default RE: phoenix decathlon


ORIGINAL: ponyracin

Sorry to keep asking questions but.... How did most of you guys run the exhaust with a four stroke on the factory mount? I was thinking about putting it in the cutout section behind the cowl and using a diverter to get the exhaust to go straight out the bottom of the fuse. Trying not to cut the cowl up anymore than I have to.
Here's how I did mine.
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Old 04-26-2007, 06:52 PM
  #183  
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Default RE: phoenix decathlon

Here are some pictures of mine. Still have a few things to do.




Old 04-26-2007, 06:55 PM
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Old 04-26-2007, 06:57 PM
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Old 04-26-2007, 07:32 PM
  #186  
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Default RE: phoenix decathlon

Jason,

Looking good, did you add a screen to the air intake? Hope that will not make her run hot!.

After posting about the exhaust ext. I checked mine and just touching it, it fell off!! The tip of the muffler on the OS is very short and not enought grip with the plastic ties so I've modified it. I used wire/plastic ties like cords are wrapped with. Threaded two thru the tie downs and then added a screw on each side of the inner firewall, wrapped around and secured so you have a pulling effect on the ext to the front. I'm sure this will solve it and not loose it in flight.

JOHN
Old 04-26-2007, 08:29 PM
  #187  
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Default RE: phoenix decathlon

No I didn't put a screen anywhere. Must be the picture.

I'm going to use one of those grey deflectors as well. I have one on my 61 2 stroke that's on my telemaster and it's been on there for a long time and never had it come off yet. Just need to find a smaller one to fit this 4 stroke.
Old 06-22-2007, 02:34 PM
  #188  
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Well it’s been a while, the weather have been really unfavorable. I took my decathlon for some air time a few weeks back and kept having bubbles in the engine lines. This caused it to keep leaning and shutting off. I took the engine off the plane and put it on a stand, it ran great, no bubbles at all. This past weekend I put everything back and guess what?... yep.. Bubbles again. I have an OS 50SX.

I increased the foam padding but this did not seem to have much effect, it helped some but did not solve the problem. So far I have changed the fuel tank, fuel lines, padding, propeller, spinner and installed rubber disks between the mount and the firewall. The engine is now running more reliable but at mid throttle I still get some annoying bubbles.

I do not know where to go from here. I know this bubbles are been caused by vibration as it runs all day on the stand, and no bubbles are been formed. I do not have a cowling on the plane. Another thing I changed was the fuel, I went from 15% to 10% this seem to have helped me some.

I have a feeling that the problem is with the fuel tank padding, maybe I have too much now. How do you guys have the fuel tank installed? Do you guys use foam padding until it is secure in there (that's how I have it) or you hold it with plastic ties, Velcro or some other way? If anyone can shine in some light I will appreciate it.
Old 07-02-2007, 11:20 PM
  #189  
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It seems that I am the only one checking this thread. What happened did you all crash the decathlon?

Well after much tweaking I found that the problem seems to be with pressure. I found that the remote needle had a fracture at the back plate where the needle holder comes out and this was causing some problems. I accidentally broke the remote needle holder arm as I was trying to figure out what was happening.

I decided to tighten up the back plate screws, drill two holes in the remaining piece of the needle holder and screwed it to the fire wall. I tested the engine and all problems are now going away.

I still get some bubbles but as soon as I accelerate they immediately disappear. The other change that I did is that I am now running about 500 rpm lower by richening the mixture. And last I changed to 10% nitro with castor oil. This combination seems to work best. I am turning a 12x6 at 11200 (+-150). So far I have 3 flights and no dead sticks.
Old 07-02-2007, 11:31 PM
  #190  
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I have also tested the use of a gyro, and I am very pleased with the results. I am using the Futaba 401 on the ruder. I connected the gain to channel 5, lower the ATV to zero for the AVCS and up to 90 for the standard. I now get almost perfect take offs. I can switch the gyro off and have normal gyro free flight. I still need to tweak it some I may up the ATV to 110 or even 125 to see what happens.

I am also going to program some differentials as IronCross suggested. I think it could help in low speed stalls which I have some problems recovering from.
Old 07-02-2007, 11:49 PM
  #191  
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Default RE: phoenix decathlon

Sargento,

I have not flown mine yet...too hot here in Arizona. I will post some pictures soon.

You can keep up with all the posts as they come in by SuBSCRIBING to this thread. Near the top of page, right side under FAQ, ...,.... Just click !

JOHN
Old 09-28-2007, 04:19 PM
  #192  
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Default RE: phoenix decathlon

Has anyone flown this plane with success in a two piece wing configuration? I just purchased this ARF and am in the process of assembling it. I drive A Mustang and there not very much room for cargo of this size. If the wing could be left in two pieces, transportation should not be a big problem. Any ideas or advice would be much appreciated. Thanks!
Old 09-30-2007, 08:19 PM
  #193  
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Default RE: phoenix decathlon

John,
My wing is already together in one piece but I also have a Mustang.Can you let down the rear seat backs and make it fit?
Old 09-30-2007, 09:38 PM
  #194  
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Yes my backs fold down, but .....I usually carry more than 1 Plane when I fly. I can lighten the load a little,but two piece wings would be sweet!
Old 09-30-2007, 09:38 PM
  #195  
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Default RE: phoenix decathlon


ORIGINAL: 3010charles

Has anyone flown this plane with success in a two piece wing configuration? I just purchased this ARF and am in the process of assembling it. I drive A Mustang and there not very much room for cargo of this size. If the wing could be left in two pieces, transportation should not be a big problem. Any ideas or advice would be much appreciated. Thanks!

Do you have a plan for linking the wing halves securely?

It looks like nobody has tried what you're interested in.

Gliders have been flown for years and years with rubber banded on wings that're held together on piano wire joiners. The bands actually keep the halves from separating. But they also provide support against the wings folding.

If you were to rely on the locating pins and hold-down bolts for keeping the halves together, they should be enough. But there would be very little to resist folding. The struts are cosmetic. Their structure wouldn't do much and would require quite a bit of change to actually provide effective anti-folding help.

You might actually be able to get enough by creating a cradle across the cabin top opening. The wing could then gain support from the cradle right at the center. That'd work for inside loops. Outsides? You'd need a method that securely locked the two halves together to get anti-fold that worked both ways.

The wing joiner is a tube and that's positive. I just don't remember if it was robust enough to rely on with the added strength the system gets from being epoxied together. It fit quite well. But no telling what the wing tubes are.

Old 10-01-2007, 06:59 PM
  #196  
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Default RE: phoenix decathlon

I have not tried this but I don’t see why it wouldn’t work.

If the center ribs don’t have enough to put a screw through them, just make two extra ribs of light plywood or basswood about 3/16 thick and glue then to each wing half.
Then just use this nylon straps http://www2.towerhobbies.com/cgi-bin...?&I=LXDMG5&P=7 something or similar and secure both half’s with them.

I get this idea from the Hangar 9 P51 PTS Mustang, look at the manual (page 7) it will provide sufficient info on how to do it correctly. (They only use one, I would use two or three)
http://www.hangar-9.com/Products/Sup...ProdID=HAN2825

My buddy has flown his P51 like this for over 50 flights with no signs of wear. Just make sure you use a few drops of thin CA on the holes where the screws go in to harden the wood.

Let us know how it all works out
Old 10-01-2007, 09:11 PM
  #197  
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Default RE: phoenix decathlon

The wing joiner tube is aluminum in the Phoenix model. I believe it even has two in there, the big one spanning half of each wing so I think it would take the stress. Could you make a hatch in one wing on the under side and use blind nuts and nylon bolts to hold it together ? Ben has semi retired his Decathlon. He enjoyed flying it for alomst a year without any mishaps at all, but says that is the only plane that made him sweat every take off and landing. He robbed the radio gear out of it to put in an Edge 540, so the Decathlon is just "hanging" out at the shop these days[&o]
Old 10-02-2007, 06:25 AM
  #198  
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Default RE: phoenix decathlon

If you're starting from scratch (to modify that ARF) there is something that would work great to hold the wings together.

Glue strong root rib doublers to each wing half. Have tabs stick down beneath. Bolt the two together to hold them together in flight. There won't be very much force trying to separate them anyway. And the wing hold down bolts are going to do that anyway AND the two hold-down stubs in the wing LE do that also. So why do it?

If you glue in a cross piece in the cabin opening that had a slot for the two new wing tabs, the slot would provide just a bit extra insurance for holding the two halves tightly together AND the cross piece would provide bracing for the wing on inside loops. Wings that are glued together gain measurable spanwise stiffness from being one piece through the center of the span.

But truth is, that wing joiner aluminum tube is quite robust and fits snugly. My ARF had only that one tube, btw.
Old 10-02-2007, 06:42 AM
  #199  
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Default RE: phoenix decathlon

Just been looking at my Phoenix Decathlon and a couple of things come to mind.

Look at yours where the two wing bolts go through the wing halves. The factory workers countersink those two holes. I guess the idea is to get the bolt heads down out of the wing. Drag you know..... Well, on mine, they "countersunk" over halfway through the wing. Not a good idea. Those bolts go through a relatively thin area of the wing, and the wing needs as much strength back there as it can get. You may have noticed that lots of wings have a plywood doubler glued back there after the wing halves are glued together. It is there to give the bolts something hard to tighten down on and to reinforce a relatively weak part of the wing and to reinforce the wing joint. On the P.Decathlon, they have inserted "hardwood" dowels back there to get the area strengthening. (and then bored out over half that strength.... amazing) anyway............

Thinking about your two piece mod, the only thing that actually bothered me about the whole deal was how the rear of the wing would stand up. There isn't anything much back there to hold the wing halves in relationship to each other. No 2nd wing pin or spar for example. And where the bolts come through, there is freespace under the wing itself. You might consider gluing in filler blocks. Then the bolts wouldn't be breaking the wing down into the cabin opening when tightened. Or........

What I think I'd do is something like the reinforcing plate bridging the two holes as mentioned above. Only with a twist.

Make a plywood plate that bridges the bottom of the wing where the two hold down bolts go through. Glue it to one wing half. It'll stick across under the other half. Both hold down bolts will go through it. And it will serve two purposes. It should definitely hold the wing halves together. And if you filler block under it, it will strengthen the wing in both inside loops and outside loops, and help keep the wing bolts tight. They'll no longer be bridging a gap. (matter of fact, I think I'm going to fillerblock mine after breakfast. Ought not to take but a couple of minutes.)

Hey, you got a good idea. Would really like to hear how it works for you. I'm betting it works great.
Old 10-02-2007, 06:51 AM
  #200  
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Default RE: phoenix decathlon

Oh yeah, I wasn't kidding about those plugs being almost drilled out to worthlessness. Check the depth of the countersinking.

I found a hardwood dowel that fit exactly. Cut some slices off to fill the missing wood.

Then, since I have Forstner bits, and am always figuring ways to do things better, pulled out a larger dowel. Countersunk a larger diameter hole down to the remaining support dowels. The hole was to fit my larger dowel. Cut slices of the larger dowel to fill the new wider hole and epoxied them in. Turned the wing over and used the old holes to go through the new plugs and it was good to go. It wasn't good to go from the mfg.

We always need to study ARFs. Their design often is excellent. But their workmanship very often needs some fixing.

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