rainedave

My Feedback: (1)

Hi all. I just snagged this OS Max 50 for $11. It was covered with forty years of grime on the outside, but when I disassembled it I found that it had hardly been run, if at all. There was lots of orange congealed castor inside, but no carbon at all on the head or piston. The ring looks absolutely brand new. The bearings are great, no rust anywhere and very smooth. I made new gaskets for the cylinder and backplate and now this thing has amazing compression. The carb is a 5A airbleed type. I don't know if it's original or not, but it's in excellent condition.

It's one of those engines where three bolts extend down and hold on the cylinder and the other three hold on the head. It takes a little planning to re-assemble. I found it easiest to get the piston and ring into the sleeve first and then install the wrist pin through the rod.

I can't wait to run it. I just need to rig up a muffler. I have a strap-on Enya that should fit fine.

Right now my plan is to take the SF .40 out of my Senior Falcon and put this .50 in its place. It's just a little bit bigger and probably lighter. I'm also thinking that it's a great match for something like a Taurus or a Kwik Fli. I have the Beach Comber plans, too. It would look great in that one.

Anyway, I just wanted to share this silk purse with y'all. It's fun to find an old, neglected engine and give it new life.

BTW, if anyone has an old OS strap-on muffler that will fit I might be interested in buying it.

David

jetranger-RCU

My Feedback: (1)

Nice find, the 50 will be perfect for the Falcon with a 11-6 prop. I had a Veco 50 in my Falcon way back when and it was great. Still have the Veco 50 may be a new Falcon should be ordered.

Bass1

My first rc trainer had an OS 50 in it and it was awesome. Today I was doing some work at a nice old residence and happened to notice an old beat up rc plane in the garage with huge vintage Kraft servos and it had a Veco 50 in the nose!

cloudancer03

My Feedback: (22)

hi raindave...I can beat you lol.I just inherited an os 50 but while it is very clean I cant get the engine to budge so I am going to take it apart .but while I got it free I sort of need a carb lol yeah theres nothing there.where can you get a carb for an os 50? is there a current engine that the carb iis compatible with the os 50..

Bass1

Seems I remember Perry used to carry carbs for OS engines, Not sure if they're still in business. Connely(sp?), the company that makes the pumps might be able to help.[:-]

rainedave

My Feedback: (1)

cloudancer03, it's a bit of an oddball size. The neck is 12mm or .472" in diameter. If you can find an OS #5A carb it will fit.

Perry makes a few carbs with a .470" that should fit if you use a good, new O-ring to seal it:

http://www.perrypumps.com/prod01.htm

I have flown mine several times on my Sr. Falcon now. With a Zinger Pro 11x6 it really hauls it around. When I back off the throttle it goes Bap-bap-bap-bap-bap like a truck. It sounds really cool!

The prop shaft is a bit short for a spinner backplate, so I'm using a Goldberg Spinner nut. Also, notice the aluminum Tatone mount.

David

NM2K

My Feedback: (14)

I learned how to fly "multi" using a Senior Falcon powered by the .58 rendition of your engine. Nice combination. That was in 1969. I had flown single channel, pulse proportional before that, with a little stick time on Ed Thompson's, McCoy .35 powered Ugly Stik in 1966. The Testor's Skyhawk RTF actually performed very, very well. Wish I still had one today. You had to be careful about getting too far away, though, because it would fly out of range.

Recently, I have acquired several of the old OS Max .58 R/C engines. It has been said that they only made the .58 in 1965. My three will be antifreezed and then pooled to make the best .58 I can get out of those parts. I used a Tatone Peace Pipe on my original .58, but I'm having trouble finding one of the larger versions on the auction sites. The smaller .19 to .40 size are plentiful, but not the larger ones. I hollowed out my original Peace Pipe with a Moto Tool and ball mill. It may have been the .40 size too.

Do you have a number for that strap-on muffler that is on your .50, Dave? I'll look around for one of those too.

Now to find a Senior Falcon kit. I had the ARF, but to make it into a replica of my original Senior Falcon would have been as much, or more, work than building a kit or building from scratch via plans.


Ed Cregger

cloudancer03

My Feedback: (22)

well the engine was cleaned up and a carb found and it runs like a charm.over the winter I will set it up in either a something extra or a H9 pulseXT40. Not what kind of strap on muffler is needed but I have a slimline strp onmuffler I used for enya's back a zillion years ago and its just getting moved around my workshop if it helps you let me know.

dennis

My Feedback: (90)

[quote]ORIGINAL: cloudancer03

well the engine was cleaned up and a carb found and it runs like a charm.over the winter I will set it up in either a something extra or a H9 pulseXT40. Not what kind of strap on muffler is needed but I have a slimline strp onmuffler I used for enya's back a zillion years ago and its just getting moved around my workshop if it helps you let me know.
[/quote


I know that it's been said before but it's an old iron and steel srt up and cnannot survive on todays fuel. It needs castor oil based fuel at about 25% total oil.
I witnessed a person totally destroy an old greenhead K&B 45 by using one of todays leading fuels. It was toast in 6 runs.
Dennis

cloudancer03

My Feedback: (22)

hi dennis I am likely confused what kind of fuel are you using on something like an older os 50I dont think the motor is is all that old although it is discontinued.are you recommending adding castor oil lubricant on top of the 18 percent?? the muffler is not for me someone here was mentioing a muffler I use a stock OS that comes with the engine.. Dennis

Bass1

We use to use "Red Max" 5% in our OS 50s back in the seventies. Worked great. Not sure what the oil percentage was though.

dennis

My Feedback: (90)

Red max fuel was castor based in the 70's and at that time was over 20% oil as were a lot of the fuels at that time. The OSMax 50 is a late 60's motor and reflects the technology of the time. There were no ABC or similar setups and they didn't appear till Super Tigre made theirs followed by K&B in the early 70's so castor was the oil to use to make sure that your motors survived. the first synthetic that was widely marketed was X2C by K&B it was basically a ucon oil. The really cheap fuels with lower oil contents were introduced about 1980 and were first advertised by a well known hobby outlet on the West coast.
Can't make you use anything but am recommending that you seriously consider a castor based fuel if you want long life from it. The OS50 also won't dazzle anyone as a 3D motor either.
Dennis

cloudancer03

My Feedback: (22)

hi dennis..I have no plan for the os 50 to be a 3D motor but it will fly my sig kougar or sig extra very nice.ok fast lol.I think if I balance out the fuel to insure sufficient castor oil I will be ok..

NM2K

My Feedback: (14)

OS has made several different .50 size engines over the years. The engine that rainedave is talking about was made during the sixties and does need some castor oil in the fuel. Being a ball bearing and ring equipped engine, it doesn't need 25% castor oil as did the contemporary lapped piston OS engines, but it wouldn't hurt a thing.

OS also made a .50 FSR some years later, which is probably the engine that you are relating to.


Ed Cregger

cloudancer03

My Feedback: (22)

I am going to check the model number specifically cause I am certain its the newer OS FSR ringed engine ..It's like brand new and I bench ran it and it runs and idles great.using 2 stroke fuel with at least 18 percent.

OzMo

My Feedback: (3)

Nice old motors guys,
I beleive the OS FSR series was the first Schnurle ported engines from OS. I have my very first RC motor its an OS 40 fsr abc and was suposed to be one of the first 40s to excede 1 HP. I just put new bearings and replaced the front end this winter still has plenty of compresion. It was in a Goldberg Eagle back around the mid 80s.

BartekSz

I am interested in buying an osmax 58. Are those engines realiable ? I know that they have 2 pistons what is little strange
Are their power is the same like in 46Fx or 55AX ? Normally they havent got mufflers ?
Can i use pistons from modern engines? or it is not possible?

NM2K

My Feedback: (14)

Hi, Bartek.

It has been so long since I've owned my OS .58, I forget if it had two piston rings or a single conventional piston ring.

No, the power output was nothing like that produced by today's OS .46AX or .55AX. These engine are schneurle ported. The old OS Max .58 R/C was equipped with a baffled piston. The .58 was originally designed as a .50 and then the displacement was increased. This means that the intake bypass port volume is not as great as it would have been if the engine was designed as a .58 originally.

Still, it powered my Goldberg Senior Falcon very well while spinning an 11x6 or 11x7 prop and burning Sig 5% nitro fuel with all castor oil lubricant. I'm glad to have found several samples in reasonably good condition. I hope to get them into the crockpot soon and get them on their way back to being beautiful.


Ed Cregger

BartekSz

I saw your movie on youtube where you renovate an old osmax 50 My will come to me mayby next week. I know that it will be much weaker than os 46ax. But in your opinion how much 20% ect? I know that this old 58 was design without any muffler so it is wery loud and light.
What means Baffled piston ?
I will propably use 12.25x3.75 APC propeller or 13x4W. This engine will be in slow and light aeroplane hmm mayby Piper or so

Edit I checked i know now how looks baffled piston

big max 1935

My Feedback: (9)

A engine w/a baffle piston is called a cross flow or loop scavanged . The piston has a ramp or a wall made onto the top of the piston on the intake side . It directs the fresh fuel charge to the top of the cylinder & not direct out the exhaust port . I also helps to push out the exhaust gasses out . Most but not all had the cylinder head made with a slot for the baffle to fit into to keep the compression up . Schnurle ported engines don't have a baffle as they have three or more intake passages & they help to push the spent charge out the one exhaust port . Some one may be able to post you a picture or drawing as I am not able to do so . Hope this is clear for you . MAX H.

BartekSz

Ok so i have this engine i get it today. But there is one problem in the head i haven't got i screw. What kind of screw there is used? In Europe we have metric screw not imperial.

big max 1935

My Feedback: (9)

OS are metric . Should be available in your country . MAX H.

big max 1935

My Feedback: (9)

Does your engine say OS MAX on the side ? If so I am junking out a wrecked one & have the screws for one . Do you need them or can you find them in Poland ? MAX H.

BartekSz

big max 1935 :
I am from Poland so it is far away from USA and sending it to my country would be expensive But thanks for help


Sorry so long but i havent got time. So whole engine was cleaned. Compression is verry good. But there is a problec because the exhaust "port" was made for a muffler and there is a place for the screw. In the photographs you can see everything. So this thing under head i only on 2 screws... And now i am a bit afraid to turn on this engine.

big max 1935

My Feedback: (9)

It would probably stay together the way it is . OS made a strap[ on muffler for this engine but they must not have had one . You could remove the two screws on both sides of the ruined area & drill into the lower case & tap it for two longer screws .It does not look like you would hit a thin area . Bolt # 6 could be fixed with either a thin nut or removing part of the fin & using a thicker nut & bolt . You can't hurt it much more . Good luck , MAX H.