OS 4A carb
04-14-2008, 01:19 PM
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OS 4A carb
Hi folks,
I have an OS 4A carb in my collection that came from a box of goodies given to me - is this a heli or aircraft carb? I have a suspicion it came from a worn out .40 heli engine but not sure.
Thanks!
MJD
I have an OS 4A carb in my collection that came from a box of goodies given to me - is this a heli or aircraft carb? I have a suspicion it came from a worn out .40 heli engine but not sure.
Thanks!
MJD
04-14-2008, 06:53 PM
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RE: OS 4A carb
ORIGINAL: rainedave
I know that it did come on the old Max-H .40 airplane engine.
David
I know that it did come on the old Max-H .40 airplane engine.
David
So.. is a "Max-H" engine a heli engine? Or is it old enough that there were no dedicated heli engines? I'm not a heli guy but understand that heli carbs are designed with a richer midrange than for aircraft use. AANd I would expect that they would have an "H" on them instead of an "A" but what do I know..
The engine won't turn by hand, but it hasn't been touched in a donkey's age, so I''ll tear it down and find out what shape it's in. If it's a runner, back goes the carb and it will be fitted to an old but unflown Falcon 56 (in photo model colors to boot). Should be a fine combo.
MJD
p.s. John - so you like the H series engines? Never had one - do tell, please!
04-14-2008, 07:53 PM
#6
RE: OS 4A carb
ORIGINAL: MJD
That''s it - that''s where it came from then. Part of this collection included a Max-H .40, but no carb on it, and various other engine bit and pieces, like 3 OS .40 size mufflers, an OS Max .35, and whatever else. So I was not 100% sure that engine was the source but it seemed like it should be.
So.. is a "Max-H" engine a heli engine? Or is it old enough that there were no dedicated heli engines? I''m not a heli guy but understand that heli carbs are designed with a richer midrange than for aircraft use. AANd I would expect that they would have an "H" on them instead of an "A" but what do I know..
The engine won''t turn by hand, but it hasn''t been touched in a donkey''s age, so I''''ll tear it down and find out what shape it''s in. If it''s a runner, back goes the carb and it will be fitted to an old but unflown Falcon 56 (in photo model colors to boot). Should be a fine combo.
MJD
p.s. John - so you like the H series engines? Never had one - do tell, please!
ORIGINAL: rainedave
I know that it did come on the old Max-H .40 airplane engine.
David
I know that it did come on the old Max-H .40 airplane engine.
David
So.. is a "Max-H" engine a heli engine? Or is it old enough that there were no dedicated heli engines? I''m not a heli guy but understand that heli carbs are designed with a richer midrange than for aircraft use. AANd I would expect that they would have an "H" on them instead of an "A" but what do I know..
The engine won''t turn by hand, but it hasn''t been touched in a donkey''s age, so I''''ll tear it down and find out what shape it''s in. If it''s a runner, back goes the carb and it will be fitted to an old but unflown Falcon 56 (in photo model colors to boot). Should be a fine combo.
MJD
p.s. John - so you like the H series engines? Never had one - do tell, please!
If it loosens up and you can run it you will better be able to feel if the bearings are bad and need replacing, (available at any bearing house.) If you use good fuel it will last another donkey''s age. They don''t make "stupid" power but they normaly start up and run fine allowing you to fly your model. It should do very well on the Falcon.
04-14-2008, 09:05 PM
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RE: OS 4A carb
ORIGINAL: Broken Wings
No the H in this case isn''''t Heli it''''s just regular Aero engine. It''''s an older engine. If it''''s stuck it''''s probably castor oil which is a good sign that it was run using the proper fuel. They need a fuel with castor oil and at least 18% oil by voulume. Sig makes a good all castor fuel. Try a heat gun to loosen it up or try soaking it in solvent before removing the backplate as gaskets are hard to find. It might loosen up.
If it loosens up and you can run it you will better be able to feel if the bearings are bad and need replacing, (available at any bearing house.) If you use good fuel it will last another donkey''''s age. They don''''t make "stupid" power but they normaly start up and run fine allowing you to fly your model. It should do very well on the Falcon.
No the H in this case isn''''t Heli it''''s just regular Aero engine. It''''s an older engine. If it''''s stuck it''''s probably castor oil which is a good sign that it was run using the proper fuel. They need a fuel with castor oil and at least 18% oil by voulume. Sig makes a good all castor fuel. Try a heat gun to loosen it up or try soaking it in solvent before removing the backplate as gaskets are hard to find. It might loosen up.
If it loosens up and you can run it you will better be able to feel if the bearings are bad and need replacing, (available at any bearing house.) If you use good fuel it will last another donkey''''s age. They don''''t make "stupid" power but they normaly start up and run fine allowing you to fly your model. It should do very well on the Falcon.
It''s an appropriate engine for the Falcon I think, and will provide plenty of power for what it meant for. I note on the recent ARF review that the modern .46 used was - reading between the lines - way too much power. No surprise!
Thanks again,
MJD
04-14-2008, 09:23 PM
#8
RE: OS 4A carb
MJD, there were a few different H .40's made. Look at the circle with the 40 in it on the side of the case. Is there a letter P (for Pylon)? Also, look at the ring. Is it conventional or Dykes? I have one of each. There was also an "RR" model made for Rat racing. Also some have a front bearing, like mine, and earlier ones have a rear bearing but a front bushing.
David
David
04-15-2008, 03:42 PM
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RE: OS 4A carb
ORIGINAL: rainedave
MJD, there were a few different H .40''s made. Look at the circle with the 40 in it on the side of the case. Is there a letter P (for Pylon)? Also, look at the ring. Is it conventional or Dykes? I have one of each. There was also an "RR" model made for Rat racing. Also some have a front bearing, like mine, and earlier ones have a rear bearing but a front bushing.
David
MJD, there were a few different H .40''s made. Look at the circle with the 40 in it on the side of the case. Is there a letter P (for Pylon)? Also, look at the ring. Is it conventional or Dykes? I have one of each. There was also an "RR" model made for Rat racing. Also some have a front bearing, like mine, and earlier ones have a rear bearing but a front bushing.
David
A shot of carb cleaner down the throat and into the cylinder and it freed up nicely with a few flips. No problem, and there seems to be all kinds of compression and bounce. So I expect it''s a runner. Don''t have a test stand set up at the moment so no data.
Thanks for the info!
MJD
04-15-2008, 07:07 PM
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RE: OS 4A carb
ORIGINAL: Broken Wings
Hmmm, "standard ring" ,"CP" wonder if that means Chrome Plated......smiles
Hmmm, "standard ring" ,"CP" wonder if that means Chrome Plated......smiles
04-16-2008, 06:06 PM
#12
RE: OS 4A carb
That would be good,....Smiles. It would last two donkey's ages....
I have no idea what the CP means but I have a HB Blitz that uses a standard ring and the cylinder is hard chromed, the regular HB dykes ringed engines are not chrome.
I checked a couple of mine and I have one that is stamped CK so it may just be a quality stamp or some kind of lot code stamp.
http://en.wikipedia.org/wiki/Chrome_plating
I have no idea what the CP means but I have a HB Blitz that uses a standard ring and the cylinder is hard chromed, the regular HB dykes ringed engines are not chrome.
I checked a couple of mine and I have one that is stamped CK so it may just be a quality stamp or some kind of lot code stamp.
http://en.wikipedia.org/wiki/Chrome_plating
