freakingfast

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I have a new K&B 100 DF engine, tuned pipe and remote mixture needle on hand that I'm thinking of putting into a speed plane. It will be turning a prop and yes the prop I will use is capable and safe.
My question is, if there are any guys out there that had ran both the K&B and the OS 91VR-DF in a ducted jet and how did they compare in power and behavior?
The specs listed are virtually identical except displacement.
Thanks.

earlwb

The K&B engine is not a high speed high RPM engine. The OS engine is a ducted fan engine though. The two engines are worlds apart from each other in that respect. While the K&B engine is a good engine, nothing wrong with it, it is intended for scale plane applications or sport planes. The K&B is intended to turn larger props for this purpose. It does not rev up all that high.  It is why the rear motor firewall mount also serves as a muffler for the engine. They wanted a scale plane engine with a little more oomph to it than a .75 or maybe a .91size engine would have. The K&B 100 is more in line with the OS 1.08 engine and how they use it.

The OS engine was intended for ducted fan applications and is designed to rev up high for that purpose. So since it revs up high it is better suited for speed applications then. I only knew guys who used them in ducted fan jet planes. I don't know of anyone actually using it as a prop engine in a plane. But I have read of a number of people wanting to do just that though.

freakingfast

My Feedback: (3)

earlwb, I'm afraid you're confusing K&B's DF engine with their R/C Aero engine. Both are 1.00" placement other than that night & day. No common major parts.

coriolan

The K&B aero and D/F 1.00 engines are very different beast!
http://www.mecoa.com/kb/67/9550.htm
http://www.mecoa.com/kb/67/9500.htm

AmishWarlord

My Feedback: (5)

freakingfast

My Feedback: (3)

The K&B Aero is rated at 2.3HP @ 9800 and the DF is rated at 4.8 Hp @ 22000 Here's a picture of the DF engine. Oops, two of you beat me to it.

coriolan

To go back to the OP, its not certain which engine (K&B or OS)would be best for a speed plane but since freakingfast
already has a complete K&B 100 with pipe why not just use it? At the time there was many options for DF (Rossi,Picco,OS and others)and they all worked well as DF power. When turbines came on the scene it pretty well killed that source of jet power so there is many large DF engines floatting around. IC ducted fan had the same requirements as glow IC for boats racing and often had version of each from the same engine base, they do well in speed planes with a proper prop choice to let them run at optimum rpm:
http://www.rcuniverse.com/forum/forumid_104/tt.htm

freakingfast

My Feedback: (3)

Good question. The K&B is somewhat rare and I don't know it's potential. The OS DF engines are so abundant and reasonably priced that if the K&B is an inferior engine, I wont wast time with it and unload it as a more valuable unused.
If for instance, the K&B makes near the same power, but at a bit lower rpm, this would be even better for my needs.
This is not exactly what I'm up to, but it shows the potential.
http://www.rcuniverse.com/forum/fb.asp?m=8008169

coriolan

If you can get a good price for that K&B 1.00 NIB it would make sense. Otherwise you might as well use it rather than have it rot on some collector display[:-]

AmishWarlord

My Feedback: (5)

Display?

I thought they and thier collector buddies just run the prices up $100 more than anyone who wants to actuly run the motor is willing to pay, then pack it away never to be seen again until their family puts up on of those "This is a RC plane motor, I don't know much about it" auctions.

piper_chuck

My Feedback: (12)

I don't have experience with either of these engines, but I did race a boat with an OS .81 VR-M. It was a great engine. In the boating circles, many feel that K&B stands for KABOOM, a commentary on their life expectancy.

freakingfast

My Feedback: (3)

That's a good one.

earlwb

Darn it My mistake, I totally missed that one. Thanks for pointing out my error.

Airplanes400

My Feedback: (349)

What do you think the K&B 1.00 DF (9550) engine is worth?
I happen to have one. I also have an extra Titanium connecting rod. Both new, never used. Have been holding onto them for years.

About the only difference I know of between the OS .91 and the K&B 1.00 is the weight. The K&B is a little heavier.

freakingfast

My Feedback: (3)

Used maybe 150, new w/box 250 but I'm just guessing. From what I've gathered researching, the rod is the engine's Achilles’ heel. It seems that a new engine has a real tight pinch and if ran rich & cold the rod goes away early, hence the market flared up for titanium rods. Now that rod is unobtainium.

The instructions didn't help matters much: "As soon as the engine fires, remove the starter and allow the engine to warm up at half throttle before removing the battery power from the glow plug.
For the first run “DO NOT� run at full throttle for more than a few seconds. Use this run to adjust the low and mid-range setting on the carburetor."

Not exactly how I'd break-in a tight, high performance ABC engine.
The instructions also don't mention it would be a good idea to have 23% oil in the fuel.

As for weight the K&B is a fraction of an oz. more when comparing head type to head type.

Thanks guy's for the help, it all adds up to build a picture, not pretty so far.

Sport_Pilot

I understand that it lasts fine if you don't run it up to high RPM.  Not sure if the rod failures had anything to do with break in.  I think they mostly broke at very high RPM as used with ducted fans.  Both K&B and OS had problems at one point or another.  I think the later versions had corrected the rod issues without titanium.

TFF

I think the K&B was developed for Bob Violett and then had a version made with his name on it.

JeffH

My Feedback: (43)

The K&B 1.00 came out after the collapse of the BVM deal. The KBV .72 and .82 were K&B engines made for BVM. From what I have read, BVM got tired of the sloppy tolerances on the K&B machining.
As far as the 1.00 goes, I know it took a special extra large pipe for it to run sucessfully in the ducted fans. I think that Century Jet Models used to sell these pipes back in the day.

Airplanes400

My Feedback: (349)

Thanks for the info. I just listed my K&B 1.00 engine here on RCU for $200
Hopefully, that price will sell it fast.

airraptor

My Feedback: (66)

I am interested in the engine just have one question. Is that rod a real titanium rod ? I see it says titan on the rod.

jessiej

Yeah. I Just read where an old, obsolete Colt revolver sold for $977,500.00. I'll bet the guy who bought it never even shoots the thing.

jess

freakingfast

My Feedback: (3)

Yup, that's what I saw years ago for the smaller engines, and yes it's hot forged titanium.

Loose the factory standard needle valve and get an "IN-FLIGHT MIXTURE CONTROL VALVE" The least expensive is the K&B, but it's likely to stay out of stock.

Scroll to the bottom of Jet Model page: http://www.jetmodelproducts.com/dynamax.htm

The most pricy but very good: http://shopbvmjets.com/zencart/index...roducts_id=105

Sport_Pilot

Hmm. Still available from MECOA. Did they run it up above the retail price?

rcdude7

My Feedback: (264)

All colt revolvers sell for premium prices because they just don't make em' like that anymore.

Sport_Pilot

They still make the SAA and they still make them that way.

http://www.coltsmfg.com/Catalog/Colt...ctionArmy.aspx