hoversmooth999

Hello to all,
I am preparing to maiden my TGA Mig-29, but I still must break in the engine. I'm running an O.S. 91 VR/DF engine on a Byron pusher set-up. My question is... I have heard that I need to mix in some extra oil with the standard 5-10% nitro fuel for my engine to run safe. It was suggested that if I am using a fuel with at least 18-20 percent oil that I must mix in an extra 2-3 ounces of oil for the engine to run safely. Is this correct? Second off, it was suggested to use an oil such as Klautz 2 stroke racing oil. Could this maybe be the same as the Honda HP2 2 stroke racing oil I have already or must I go buy the Klautz formula? Just want to be sure. Thank-you.[8D]

Terry Holston

My Feedback: (1)

Go get yourself some Wildcat Jet-A 5 % nitro fuel. It has 2% oil (Klotz) already in it, and Run your engine. Set the needle slightly rich with a good smoke trail out the exhaust. If it will Idle for 30 seconds and then take full throttle without quiting, 2 or 3 times in a row, fly it. Break it in in the air!!!!

mikuk

Hi,
As Wildcat fuel is no longer available in the UK I have to mix my own, 5% nitro,5%castor,18% Klotz, works for me, but if you can get it use Wildcat its the best for the OS91 I've come across.Mike

JimBrown

My Feedback: (2)

I'll add my .02 cents in favour of Wildcat Jet-A 5% fuel for your OS .91. I've been using it for years and will not use anything else. I've got 16 gallons of it in my basement!

As Terry mentioned, break in can be pretty much done by flying the jet. That being said, I still prefer to run a full tank through the engine at full power on the ground first with a pretty rich setting. Not slobbering rich, just a bit richer than what I'd use in flight. After the first tank, set the needle a little bit leaner and go fly. Also, as Terry mentioned, you should have a pretty good smoke trail out the back at all times.

...jim

Edgar Perez

My Feedback: (13)

1 oz turbine oil per gallon

hoversmooth999

Thanks for the help guys,
Sadly, My side of Texas is scarce of Hobby shops and they do not stock much of anything much less Wildcat. I was able to purchase some the Klotz racing oil today though along with a gallon of PowerMaster 5%nitro by 18%. As suggested my the guy at JD Enterprises, I will add about 2-3 ounces to the gallon. As far as the breaking of this engine in the air.... I am a little weary about it. I hope ya'll are'nt joking, but I'll give it a try. How should I go about flying in the air? Any rules on when to throttle up? Thanks[8D]

kdhpga

My Feedback: (2)

What prop do you use to break-in the OS 91 on a test stand with a large head or is "in the air" o.k.? I assume that it would get too hot running in the TGA F-15 on the ground with a Byron fan behind the engine.
Kirk

donniercjet

My Feedback: (10)

i use byron 5% nitro with 18% or 20% oil content. i have the o.s. 91's and rossi 81's. i agree with jim run a tank or 2 through the motor on the ground. my .02 cents worth

Pizzazz

My Feedback: (22)

I have flown ducted fans for years. We have discovered a great ducted fan fuel. If you have access to Riches Brew 10%, 11-11 (which is produced here in Texas), that is the way to go. This fuel contains 22% oil, mixed 11% synthetic and 11% castor. A gallon runs you about $10 bucks.

We purchase ours thru Mike's Hobby Shop in Carrolton, Texas (suburb of Dallas). This fuel has performed extremely well for us and the extra oil is very friendly to the high turning RPM's of the OS-91. No additional mixing of oils required.

Good luck.

hoversmooth999

Thanks a bunch for the info,
To donniercjet, do you mean by running those tanks on the ground, in the jet, or on a testing stand? Thanks.
Also I'm south of San Antonio. A pretty good distance away from Carrolton, but many thanks and hope to hear any more comments. Maiden is set for a week from now![8D]

Edgar Perez

My Feedback: (13)

I forgot to mention that this ounce is to be added to standard 15% glow fuel. This was recommended by Larry Wolfe from Jet Hangar Hobbies.

JohnnyA

My Feedback: (1)

quote:

ORIGINAL: Edgar Perez

1 oz turbine oil per gallon

I forgot to mention that this ounce is to be added to standard 15% glow fuel. This was recommended by Larry Wolfe from Jet Hangar Hobbies.


NO WAY should you run an OS .91 VRDF on 15% fuel!
Stick with 5% and save yourself all kinds of grief.
JA

Terry Holston

My Feedback: (1)

The reason I stated to break your OS.91 in the air is.............................On the ground it will overheat as it can not get enough air over the head to keep it cool. DO NOT USE A PROP on a byron large head engine to try to break it in.....you will probably just BREAK it. [] Run it long enough to get a reliable idle and FLY IT!

hoversmooth999

Thank-you to all members,
I will go ahead and try the in-air bread-in procedure. And also I do agree not to use anything higher than 5-10%. This engine was designed much differently than others and I also know this from many other accounts of not using a fuel with any higher than 10% nitro. Thanks. I will let ya'll know how it goes as soon as this berzerc Texas weather clears up.[8D]

ianober

My Feedback: (12)

I ran my OS.91 on 15% nitro WIldcat Heli fuel and it ran great. I added 1 oz. of Turbine oil to the fuel and that is the reason why you can run 15%. It ran like a champ and didnt even need an inflight mixture valve.

mafrasca

So far I've run 10% castor, 10% Klotz & 5% nitro. It seems to be OK but I think the synthetic is giving up on me when the mixture gets a little lean, so I'm going to try a larger % of castor and throw in some turbine oil for good luck. At these high temperatures and pressures the engine needs the most protection it can get so I'm hoping the turbine oil will help out. Changing the piston & liner can get expensive after a lean run. By the way does turbine oil mix well with methanol based fuels?