Oriental Rebirth Troubles

[Chris Fretz]

Well I got a chance to try this repaired Oriental over the weekend. First day the engine run was all over the place. I took the engine out an tried sealant on the backplate in hopes of the problem being that. On the second day it needled a little better but still not a very good run. I wonder if something happened to the tank when I crashed it.  I pressure checked it during the rebuild an it checked out ok. I'm not sure what to try now.

[Dan Berry]

Put a new glow plug into it.

[kenneth cook]

           Also check fuel lines, in the event of a crash, it's not uncommon for the tubing to be cut. You might not even immediately notice the cut in the tubing until you bend it. Carefully inspect or just replace all tubing. Make certain the needle valve itself didn't get bent.

[Motorman]

Could be dirt in the tank. Sometimes a blob of solder will break loose and work it's way to the pick up tube after launch. Flush the tank with alky or some solvent to get the castor out then shake it to hear for a rattle inside.

MM

[Chris Fretz]

Put a new glow plug into it.

Already had 2 different ones in it.

           Also check fuel lines, in the event of a crash, it's not uncommon for the tubing to be cut. You might not even immediately notice the cut in the tubing until you bend it. Carefully inspect or just replace all tubing. Make certain the needle valve itself didn't get bent.

I did pressure check it with the original tubing on it.

Could be dirt in the tank. Sometimes a blob of solder will break loose and work it's way to the pick up tube after launch. Flush the tank with alky or some solvent to get the castor out then shake it to hear for a rattle inside.

MM

Nothing was rattling when I had the tank out, I did flush it with alcohol.

[Bill Johnson]

What kind of tank? If it's metal, you could have an internal problem and it will still pass a leak check.

[Chris Fretz]

What kind of tank? If it's metal, you could have an internal problem and it will still pass a leak check.

The fellas say it was a standard Brodak uniflow tank.

Sounds like the fuel is foaming about half way through the flight. What engine are running? It's doing a good 4-2-4 run.  Do you have a filter in the line between the tank and engine? That usually breaks up bubbles and keeps the run steady.  Also how much oil and what type(s).

I started a new thread from this one http://stunthanger.com/smf/open-forum/good-times-bad-times/

LA 46, has a filter, Omega 10% with a cup of castor added to a gallon.  It probably is foaming the way it's running erratic on the ground. I just left it mounted the way it was, just wedged in with blocks. How do you guys mount them inside the body?

[Perry Rose]

There is vibration in the nose. You need to add another layer of balsa to the tank floor and glue it well. I've had this problem many times. Put some thin strips of foam rubber around the tank.

[Dennis Moritz]

Check the engine mounts for rigidity. The front end might have loosened up. It's possible to make a plywood or aluminum reinforcement bolted to the top side of engine above engine mounts. Use ply spacers to raise plate so it clears bottom of engine. Use longer engine bolts if needed. Bolt reinforcement to these bolts. Cinch bolts hard. I cured a bad engine run using a plywood plate like this on an Oriental. On profiles I use aluminum plates similarly. They are bolted opposite to engine using engine mounting bolts.

[Chris Fretz]

There is vibration in the nose. You need to add another layer of balsa to the tank floor and glue it well. I've had this problem many times. Put some thin strips of foam rubber around the tank.

There is vibration in the nose. You need to add another layer of balsa to the tank floor and glue it well. I've had this problem many times. Put some thin strips of foam rubber around the tank.

Do you suppose when I cut out the softer engine mounts with the hot glue an put in maple mounts with epoxy is causing it to have more vibration?

[Dennis Moritz]

Yes. That is possible. Harmonics that exaggerate engine vibration are difficult and hard to anticipate. Many of us have had model with rigid mounts that picked up a bad vibe.


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[Chris Fretz]

Yes. That is possible. Harmonics that exaggerate engine vibration are difficult and hard to anticipate. Many of us have had model with rigid mounts that picked up a bad vibe.


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Do you think trying to make it more rigid like you mentioned would help if what I did may have caused more vibration?

[Dennis Moritz]

It has helped models I've made.


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[Dennis Moritz]

Vibration issues are tricky, often difficult to cure. Incremental improvements are frequently the case. True to my experience, in any case. I've an Oriental ARF that has been handed back and forth between myself and a friend. It had aerodynamic issues and engine run issues. My friend wound up taking it apart, removing the wing, peeling the covering. He discovered a weekend center section, probably complements of some mod I made that didn't work. He fixed that. A very nice looking bird was the result. The plane then had engine runaway issue that he couldn't solve. In frustration, he gave the plane back. After a plywood plate was installed as described above, engine runs settled down. These plates have helped various profiles. Seems to make the mounting system more rigid. This year's comp plane was a very nice RD-1 built by someone else. Vibration issues were helped in a similar way. Helped but not solved. After trying many different ideas, a friend said wrap the tank in bubble wrap and rubber band the tank on. Wrap it just tight enough to keep it in place. Not over tight. It's a profile. There's room to do that. That did it. Engine runs are much more predictable.

[Mike Haverly]

All of the replies seem OK except, the engine sounds like it's way too rich on the ground.  After it gets into the air and unloads it is trying to run at its happy speed.  LA's don't like to be loaded and like a constant four-stroke even less, forget a break.  I would try a prop with less pitch and more RPM. 

I notice in your other thread you were using a 12x4 Zinger.  Those props work real well for stirring pain and that's about it.  An 11 1/4 x 4  or 12 1/4 x 3 3/4 APC would make the engine much happier.

Zinger props need a lot of rework to make them work better.  Just not worth it when there is off-the-shelf stuff that works better.

There is a large thread in the engine set up section of this forum that will back up what I just stated.

[Chris Fretz]

Vibration issues are tricky, often difficult to cure. Incremental improvements are frequently the case. True to my experience, in any case. I've an Oriental ARF that has been handed back and forth between myself and a friend. It had aerodynamic issues and engine run issues. My friend wound up taking it apart, removing the wing, peeling the covering. He discovered a weekend center section, probably complements of some mod I made that didn't work. He fixed that. A very nice looking bird was the result. The plane then had engine runaway issue that he couldn't solve. In frustration, he gave the plane back. After a plywood plate was installed as described above, engine runs settled down. These plates have helped various profiles. Seems to make the mounting system more rigid. This year's comp plane was a very nice RD-1 built by someone else. Vibration issues were helped in a similar way. Helped but not solved. After trying many different ideas, a friend said wrap the tank in bubble wrap and rubber band the tank on. Wrap it just tight enough to keep it in place. Not over tight. It's a profile. There's room to do that. That did it. Engine runs are much more predictable.

Sounds like I shouldn't of wrecked it thanks for the ideas,  I'll see what I can do.

All of the replies seem OK except, the engine sounds like it's way too rich on the ground.  After it gets into the air and unloads it is trying to run at its happy speed.  LA's don't like to be loaded and like a constant four-stroke even less, forget a break.  I would try a prop with less pitch and more RPM. 

I notice in your other thread you were using a 12x4 Zinger.  Those props work real well for stirring pain and that's about it.  An 11 1/4 x 4  or 12 1/4 x 3 3/4 APC would make the engine much happier.

Zinger props need a lot of rework to make them work better.  Just not worth it when there is off-the-shelf stuff that works better.

There is a large thread in the engine set up section of this forum that will back up what I just stated.

That zinger prop looks like a bunch of toothpicks now. I had a APC 12x4 on there. I've used that 12 1/4 x3.75 but it seems like the airplanes pull like crazy and do about 3 sec lap times for me.

[Steve Helmick]

It sounds like the tank is loose in the nose. Wedges of soft balsa, layers of balsa, maybe a shim of 1/32" or 1/64" plywood, could make a lot of difference. Foam might work for awhile.

When you change the prop size/brand, it often takes several flights to get the correct launch rpm, so don't hesitate to try the 12.25 x 3.75 again, just launch richer. One of the beauties of the APC props is that they are very consistently good stuff. Zingers are also very consistent, but not in a good way. Zinger = Prop Kit.    Steve 

[Chris Fretz]

It sounds like the tank is loose in the nose. Wedges of soft balsa, layers of balsa, maybe a shim of 1/32" or 1/64" plywood, could make a lot of difference. Foam might work for awhile.

When you change the prop size/brand, it often takes several flights to get the correct launch rpm, so don't hesitate to try the 12.25 x 3.75 again, just launch richer. One of the beauties of the APC props is that they are very consistently good stuff. Zingers are also very consistent, but not in a good way. Zinger = Prop Kit.    Steve 

What is a Prop Kit?

[Mark Scarborough]

What is a Prop Kit?

a Prop Kit is a chunk of wood that resembles a prop,, but generally requires a lot of work to make it actually function reliably as a prop,, the Zinger and top flight Pro are perfect examples, some of the props are actually made out of a reasonable chunk of wood but the blades are very thick, the airfoil is clunky and poor, and they require a few hours of work, and a pitch gauge to make anything meaningfull happen when you bolt them on an airplane,,
they are a lot like the black Master Airscrew props,, horribly inefficient and not very accurate pitch wise,,

[Chris Fretz]

a Prop Kit is a chunk of wood that resembles a prop,, but generally requires a lot of work to make it actually function reliably as a prop,, the Zinger and top flight Pro are perfect examples, some of the props are actually made out of a reasonable chunk of wood but the blades are very thick, the airfoil is clunky and poor, and they require a few hours of work, and a pitch gauge to make anything meaningfull happen when you bolt them on an airplane,,
they are a lot like the black Master Airscrew props,, horribly inefficient and not very accurate pitch wise,,

Lol you guys an your airplane lingo!

[Mike Haverly]

Here are a few Zingers that I reworked about 10 years ago when I thought it might be important.  I soon found out it was better (for me) to use props that were readily available and repeatable.  APC's are pretty reliable, as are many others.

That .46 you are using is a good power plant but maybe too much for an Oriental.  I have one in my Freedom 45 which is a classic model with a 60" wing span and 660 sq. in. and weighs in at nearly 60 oz.   It pulls it easily with a 11 1/2 x 4 APC.

Foaming for one reason or another may well giving you fits but trying to tame the power could be causing problems as well.  Using a prop too large for the airframe will make it hard to fly and trying to slow it down by making the engine do something it doesn't like may be the wrong approach.

 

[Jim Svitko]

a Prop Kit is a chunk of wood that resembles a prop,, but generally requires a lot of work to make it actually function reliably as a prop,, the Zinger and top flight Pro are perfect examples, some of the props are actually made out of a reasonable chunk of wood but the blades are very thick, the airfoil is clunky and poor, and they require a few hours of work, and a pitch gauge to make anything meaningfull happen when you bolt them on an airplane,,
they are a lot like the black Master Airscrew props,, horribly inefficient and not very accurate pitch wise,,

I agree.  I re-worked some Zingers and was able to make them perform reasonably well.  I suppose I wanted to see if I could do it.  But, what is someone's time worth?  I would rather put my time into something else and just get a prop that works off the shelf, or with very little modification.

If you must have a wood prop the BY & O from Brodak are very good.  Too bad that the sizes I use the most are out of stock at times and it takes a while to get the inventory resupplied.

[Chris Fretz]

Do you guys take a APC off the shelf and bolt it on or do you guys at least balance them first?

[Mike Haverly]

Yes Jim, I came to the same conclusion.

APC props, like any other, need to be balanced.

[john e. holliday]

Yes, check balance as you knock the razor sharp edges off them.  So far I haven't found a wood prop with edges sharp enough to cut while flipping the prop as my son found out with an APC.

[Chris Fretz]

I figured you guys balanced them. I've talked to a few guys that told me they don't.  I don't know how they do it.

[Steve Helmick]

I'd like to know more about the current Brodak Y&O props, because when they first came out, they were not much to brag about. I tried some genuine Bull Y&O props and didn't find any magic with them, either. Those were hand worked to some degree at the "factory" (I seem to recall that Clarence Bull had his shop setup in an old gas station), and therefore inconsistent.

Are "B&Y&O" props now made in China on a CNC Router by Xoar? If they ARE, I'd be interested in trying them. Otherwise, I might be interested in trying them, or maybe not.  Steve

[Brett Buck]

Yes, check balance as you knock the razor sharp edges off them.  So far I haven't found a wood prop with edges sharp enough to cut while flipping the prop as my son found out with an APC.

  There doesn't seem to be any harm in just taking 240 grit sandpaper to the trailing edge until they don't cut your finger any more.

     Brett

[Steve Helmick]

I figured you guys balanced them. I've talked to a few guys that told me they don't.  I don't know how they do it.

Either they're blowing smoke, or they aren't very experienced, old or young. A good balancer will cure a lot of ills, but not all.  Steve

[Tim Wescott]

Do you guys take a APC off the shelf and bolt it on or do you guys at least balance them first?

Mostly I put them on the balancer and find out that they're close enough as they are.  But sometimes I need to spiff one up.  You should always check (after taking of the price tag  )

[Mark Mc]

Mostly I put them on the balancer and find out that they're close enough as they are.  But sometimes I need to spiff one up.  You should always check (after taking of the price tag  )

My findings exactly.  I balanced two new APC 10x4 props last week, and one was actually spot on, one needed the most minor of shaving.  I'm liking the APC's more and more.

Mark

[Chris Fretz]

Some of the APC balance fast for me an others I have to hog a lot off the hub. All the while wondering if I'm doing it right sometimes. I despise balancing wood props. I just did 2 Zoar 12x4s an the one didn't have a untouched spot on it. I've been using the Du-bro tru-spin with the flat side of the cone on the back side of the prop with the cone shape on the front side of the prop. Sometimes I swear it messes with me (maybe the wheels get dirty I don't know)  I wish there was a reasonably priced automatic balancer 

[Bill Johnson]

Some of the APC balance fast for me an others I have to hog a lot off the hub. All the while wondering if I'm doing it right sometimes. I despise balancing wood props. I just did 2 Zoar 12x4s an the one didn't have a untouched spot on it. I've been using the Du-bro tru-spin with the flat side of the cone on the back side of the prop with the cone shape on the front side of the prop. Sometimes I swear it messes with me (maybe the wheels get dirty I don't know)  I wish there was a reasonably priced automatic balancer 

I do them pretty fast using thick CA and accelerator on the hub. The APCs seem to have more hub issues while the typical wood props seem to have more blade issues. I like me True Flight balancer that uses a magnetic field instead of the wheels. It's about as close to zero friction as you can get. They even tell you how to use it as a wind speed indicator.

[Mark Scarborough]

APC props I have had, many many,many of them ( hey I used to break a LOT of props)
they al lbalanced out of the package,, the secret is that you have to look at the hole in the hub.
there is that stepped portion, ( wheere the little rings fit into the prop on the backside.) That part of the hole is the centered portion, the actual through hole is not always centered. I dont know why but it isnt, so to balance the prop, or when you bolt it on the motor, the stepped portion of the hole is what is the balance/center, not the smaller through hole, so in My experience, I ream the center hole so it does not locate the prop and use the rings to locate the prop on the shaft.. or balancer,, its pretty hard to balance a prop that isnt centered,, 
APC directions for balancing
https://www.apcprop.com/Articles.asp?ID=259#balance

and here is a comment on their page about the holes
Engine Shaft Hole Alignment

The propeller hub aft surface and aft hole are precisely defined during molding. However, post-molding shaft hole drilling may induce minor angular miss-alignment of the propeller with the engine shaft. This hole miss-alignment is avoided by use of a tapered reamer to slightly enlarge the propeller hole forward of the aft surface. This causes the propeller to precisely register with the engine shaft at the aft surface and hole.

( from this page,,,,  https://www.apcprop.com/Articles.asp?ID=259#holealign)

Likewise, every single Xoar prop I have taken out of the package has been perfectly balanced,

[Tim Wescott]

I'm worse than Mark with APC props -- I just test the balance of the prop with the balancer set up to center on the smaller of the two holes (I use the whothehellmakesit dual-magnet balancer that has the tapered prop holders -- I run the taper of one holder into the small hole, and the butt end of the other holder into the back of the prop).  Things almost always balance plenty good enough for me.

If they're drilling the props fast and inexpensively then I could see how they'd introduce some uncertainty.  But given my luck so far, I think they're people who believe in promising a little and delivering a lot -- which is my kind of craftsman.

Mark -- where do you get balance rings?

[RknRusty]

I just deleted my post I was writing when Mark got in ahead of me. I was suggesting you place the balancer cone in the hole that grips the crankshaft and adding/removing hub weight. But my APC prop blades are always balanced out of the package too, and apparently I've been compensating for the front hole mis-alignment. So I'm ordering a reamer and switching methods today. Even though I've read this, my hard head resisted and I've wasted a hell of a lot of time grinding flat spots on the hubs.
Thanks Mark.
Rusty


And now Tim jumps in as I'm revising. I stack tubing to make the holes snug on the crankshaft.

[Chris Fretz]

APC props I have had, many many,many of them ( hey I used to break a LOT of props)
they al lbalanced out of the package,, the secret is that you have to look at the hole in the hub.
there is that stepped portion, ( wheere the little rings fit into the prop on the backside.) That part of the hole is the centered portion, the actual through hole is not always centered. I dont know why but it isnt, so to balance the prop, or when you bolt it on the motor, the stepped portion of the hole is what is the balance/center, not the smaller through hole, so in My experience, I ream the center hole so it does not locate the prop and use the rings to locate the prop on the shaft.. or balancer,, its pretty hard to balance a prop that isnt centered,, 


Likewise, every single Xoar prop I have taken out of the package has been perfectly balanced,

Do you have a picture of what you are taking about with these rings?

What did I do wrong with the Zoar cause both were not balanced out of the package according my balancer.

Ha better yet make us a video Mark

[RknRusty]

As far as I know, those rings only come with the e props. They also come with spinners like Dubro, Great Planes and Dave Brown in my experience, but they are for locating the spinner backplate, not the prop.

But what they are talking about is that when you take an APC out of the package, the front hole usually fits, sometimes very tightly, onto the crankshaft. But it is not the centered hole, and should be drilled or reamed out so that the rear hole actually locates the prop on the shaft. The rings adapt the size of the hole to the shaft so it's truly centered.

What we hacks have been doing is using the wrong hole from balancer to plane and compensating for the non-precision location of that front hole. You can use short pieces of K&S tubing to stack outward to adapt the shaft to the truly centered rear hole in the APC prop. And put the pointy end of the balancing cone into only the truly centered rear hole when balancing. I'd say bore the front hole first so as not to interfere with the balancer cone.

I think our old Hack way is okay, but a lot of unnecessary trouble, and never as perfect as the right way.

If I was not sure that was right, I would not have posted it.
Rusty

[Mark Scarborough]

Do you have a picture of what you are taking about with these rings?

What did I do wrong with the Zoar cause both were not balanced out of the package according my balancer.

Ha better yet make us a video Mark

the links I posted show what I am talking about with the APC props,, look and see,,
the rings only come with electric props, my bad, but the links describe how to treat the glow props,, basically  the small hole is drilled after the fact and should never be the centering point if at all posibble, go read the links I had in my email

as to Xoar,, I can only surmise your balancing method may be flawed, its very easy to bend the shaft on a balancer,, what are you using to balance, how long have you had it, and have you triple checked to insure its accuracy?

I have friends who fly the big Gas powered RC models, swinging a 18 or 20 XOAR prop, he does the same as he does with apc props, takes them out of the package and bolts them on,, ( no I do not agree with this method) and has never had a problem,, ok well there was one time it was way off balance, but that was after he smacked the ground taking off and lost a blade LOL

[RknRusty]

Mark, do you see anything wrong with about what I posted above your last post?
Rusty

[Mark Scarborough]

not off the cuff,
The web site recomends a piece of fuel tubing to center the prop,, I have had probably 80% success with the drilled hole being centered, so its an option, if it balances using the center hole then its probably ok to use the center hole,, if it doesnt balance then the center hole is in the wrong place, I find it pretty unlikely that the plastic injection could vary density enough to be out of balance IF THE HOLE IS centered

[RknRusty]

not off the cuff,
The web site recomends a piece of fuel tubing to center the prop,, I have had probably 80% success with the drilled hole being centered, so its an option, if it balances using the center hole then its probably ok to use the center hole,, if it doesnt balance then the center hole is in the wrong place, I find it pretty unlikely that the plastic injection could vary density enough to be out of balance IF THE HOLE IS centered

Okay, good. My new ones almost always hang horizontaly on the balancer with the cone in the small front hole, and prefer one side facing down. That's what I usually remove hub material to fix, but it's tedious to get perfect. I'd forgotten, I do use fuel tube on some 1/2A engines.

Next time I use a new prop, I'm going to bore out the front hole and see if it balances on the first try with the cone in the rear. I say bore first, because the cone won't seat all the way in the rear hole if I don't. At least not with anything 12" or under.
Rusty

[Bill Johnson]

I've been pretty careful about balancing props because I know what kind of problems they cause on full size aircraft. The first thing I check when the prop goes on the balancer is the blade track. Both tips have to fall in the same plane of rotation. Full size props are only allowed something like 1/8" so I don't allow any out-of-track model props. I would think the track would immediately show the blades out of track if the center hole was off. If I recall correctly, I use the cone on the back side (the side closest to the engine) and the flat cone on the front.

P.S. I just reviewed their website and do it just as they recommend. I also watched a video I believe they put out about prop balancing which was where I learned about using the thick CA glue to balance the hub. They clearly show balancing using the aft hole to center on the balancer then boring the front hole and using the tubing for install on the engine.

[Chris Fretz]

APC props I have had, many many,many of them ( hey I used to break a LOT of props)
they al lbalanced out of the package,, the secret is that you have to look at the hole in the hub.
there is that stepped portion, ( wheere the little rings fit into the prop on the backside.) That part of the hole is the centered portion, the actual through hole is not always centered. I dont know why but it isnt, so to balance the prop, or when you bolt it on the motor, the stepped portion of the hole is what is the balance/center, not the smaller through hole, so in My experience, I ream the center hole so it does not locate the prop and use the rings to locate the prop on the shaft.. or balancer,, its pretty hard to balance a prop that isnt centered,, 
APC directions for balancing
https://www.apcprop.com/Articles.asp?ID=259#balance

and here is a comment on their page about the holes
Engine Shaft Hole Alignment

The propeller hub aft surface and aft hole are precisely defined during molding. However, post-molding shaft hole drilling may induce minor angular miss-alignment of the propeller with the engine shaft. This hole miss-alignment is avoided by use of a tapered reamer to slightly enlarge the propeller hole forward of the aft surface. This causes the propeller to precisely register with the engine shaft at the aft surface and hole.

( from this page,,,,  https://www.apcprop.com/Articles.asp?ID=259#holealign)

Likewise, every single Xoar prop I have taken out of the package has been perfectly balanced,

Ok so I looked at Brodaks hobby shop on Saturday. The back of the props are .315, so the very best ring that would even fit was a ring that came with a 6x4 prop. The bag of rings you could buy won't fit in the back of the prop as the OD of the ring is .375 for electric props. Plus the only ring i found to fit still had the the hub of the prop pulling on the balancer.

I must be missing something something here?!?!

[Chris Fretz]

More pictures

[Chris Fretz]

Some more...

[Chris Fretz]

Electric rings with no hope of fitting.

[RknRusty]

...I must be missing something something here?!?!

Yeah, you're mising a box of K&S assorted tubing bits and pieces
http://www.ebay.com/itm/NEW-K-S-Tube-Assortment-320-/291268619718?hash=item43d0f66dc6

[Chris Fretz]

Yeah, you're mising a box of K&S assorted tubing bits and pieces
http://www.ebay.com/itm/NEW-K-S-Tube-Assortment-320-/291268619718?hash=item43d0f66dc6

Didn't Mark say he uses electric rings?

[Chris Fretz]

Yeah, you're mising a box of K&S assorted tubing bits and pieces
http://www.ebay.com/itm/NEW-K-S-Tube-Assortment-320-/291268619718?hash=item43d0f66dc6

Plus how in the world do you use a piece of fuel line to center a prop? I see the pictures on APC web site but I totally don't get it.