big mig .25 for flite streak?
 

Just wondering if this might be a tad too much engine for this plane. (All the other Norvels I have are absolutely dynamite engines, putting out power equivalent to way larger engines).

I know: I'm s'posed to put an O.S. .20--but they ain't that EZ to find anymore.

How 'bout an O.S. .25 Max for this ship?

Thanx, y'all,
M

RE: big mig .25 for flite streak?
 

Should be fun plane with the .25. There are a couple running with them here. They are a little fast, but nothing wrong with that at all.
Lee TGD

RE: big mig .25 for flite streak?
 

Thanx, Lee, for the assurance.

Wondering, too, if I should shoot for a strictly CL engine, or can I get away with trying a throttled RC engine. cobbled wide-open?

(Much prefer the simplicity of a venturi/needle-valve setup--but there are WAY more RC engines out there for sale).

Anybody had any luck with a throttled/carb RC engine on a CL plane?

Thanx,
M

RE: big mig .25 for flite streak?
 

I'm using an r/c P.A.W. 09 diesel in my Marquis. I just wired the throttle wide open. Seems to do the job O.K.

RE: big mig .25 for flite streak?
 

Secureing the throttle open will work ok. I think I would purchase or make a c/l venturi and get a needle valve assy if I liked the way the plane flew and handled. It may make it a little more consistant. Either way should be fun flyer.
Lee TGD

RE: big mig .25 for flite streak?
 

The FS ought to be a hoot with the BigMig. Wire the carb open and go for it. The FS likes to fly a little faster than modern "stunt" planes. It was meant for combat wayy back when, anyway. I haven't seen one of the 25s-keep us posted on how it goes.

RE: big mig .25 for flite streak?
 

As previously stated the original Flite Streak was designed for combat/stunt. Mostly used for combat in our club. Johnson, K&B and Fox 35 combat engines. Best was around 80+ on .018 cable lines. Don't know your experience so I would say wire the throttle open and go for it. Also get out and fly. DOC Holliday

RE: big mig .25 for flite streak?
 

Actually, if it's too much power you can throttle it down a bit and still run near peak setting if you leave the RC carb on. Or, you can just richen the needle a bit.

George

RE: big mig .25 for flite streak?
 

Kool! I'm so anti-RC, never realized a throttle/carb setup might be JUST the ticket, if the engine's too strong for the plane/pilot.

Scored two engines last nite; a K&B .20 Sportster, and a Norvel .25. Ain't sure if the latter's a big mig or not. Just has NV .25 embossed on the cylinder wall.

Figured I'd start out ez, with the .20, then graduate to the .25 as skill and confidence develop--that's assuming skill and confidence DO develop. Lotta feedback on searches for "K&B Sportster," but it's all been RC. Any of you CL flyers had any experience with this K&B model?

Thanx, gcb, for the common sense response.

RE: big mig .25 for flite streak?
 

It might be worth asking over at SSW about the K&B Sportsters. I think some one out West has been running either the 20 or 28. A Ro-Jett it ain't, but given plenty of castor oil and a low pitch prop like a 9-4 or so, it might make a pretty decent sport motor.

You're right, the 25 is not called a BigMig.

RE: big mig .25 for flite streak?
 

My Big Mig .25 has "BIG MIG" on the engine mounting lug below the .25.

The K&B Sportster .20 was replaced by the .28. I have two of the .20's. Note that the cylinder is AAC and does not have a liner. When the cylinder is worn out you would have to get it re-chromed or chuck it, so use an adequate amount of lube. If you got the whole package, it came with a muffler and a radial mount backplate.

Edit2: This is no longer true. Apparently the engine is being made again by K&B/MECOA and the cylinders (jugs?) should be available. Also, the new version has a remote needle valve assembly.

Good luck with both of them.

George

Edit: Forgot to mention, the NV .25 should have included a spanner wrench for the head.

RE: big mig .25 for flite streak?
 

George comes up with some pretty sound advice --

If the NORVEL .25 is a Big Mig, it will be bushed and have a single needle carb. The AME is a twin bearing engine with a dual needle carb. You can slip the thrust washer off the prop shaft and easily see if it is bushing or bearing.

RE: big mig .25 for flite streak?
 

Yeah, turns out is is a big mig.

Got this guy as-is, and I'm wondering if this is a serious or minor prob. You can see, from the attached snap, that there's something broken off, where the prop attaches.

What I'm hoping is that this is only the retainer nut that's severed, and not the crankshaft itself that's broken.[img][/img]

Engine still turns over and has good compression, so I'm thinking it's maybe just a job for an "easy-out."

Can y'all tell?

Thanx,
M

RE: big mig .25 for flite streak?
 

The .25 uses a replaceable prop shaft that is reversable -- you can screw either end into the crankshaft, depending on the thickness of the prop hub. The shaft is a standard M6x1.0 so you can simply replace it with a stainless or alloy socket head bolt or find a piece of M6 allthread if you want to use the original propnut (locate a M6x1.0 fully threaded bolt and cut off the length you need). The engine probably has taken a pretty good whack to break the shaft, so you might want to check runout.

If you want to stay original, get a propshaft from [link=http://www.norvel.com]NORVEL[/link] or [link=http://www.sigmfg.com]SIG[/link]

RE: big mig .25 for flite streak?
 

Thanx, Andrew, for the tip--and for the actual pic. Did find this article at SIG--though it didn't come with your handy pic, so I wouldn't have known it included the the nut--or maybe it doesn't?

Also looks as if the rear hub is missing.

And yes, I was trying to imagine what kind of impact it would take to break the shaft like that. I've crashed a LOT of planes, bent cooling fins and needle valves and such--but I've NEVER broken a prop shaft.

First thing I did was pull the plug and slither a little Marvel Mystery oil down into the head, then carefully turned the crank. No binding, and with the plug back in, compression feels good, so I'm hopeful the crank's not warped.

RE: big mig .25 for flite streak?
 

The shaft and nut are sold as a set, part # NVL401211 for your Big Mig. The rear prop hub for the Big Mig is NVL400322.

RE: big mig .25 for flite streak?
 

Kool. Thanx, for those part #'s, Andrew. And buying both at once will kinda take the sting out of SIG's 7-buck S%H fees.

RE: big mig .25 for flite streak?
 

The K&B Sportster can be modified to a venturi and NVA by buying the venturi and nva for the Fox 25BB. It drops right in. To slow it down if you want to a piece of 1/4 inch tubing lightly flared and secured by the nva will work extremely well. Do not try for a 4/2/4 run as it wont do it. Use fuel similar to a Fox 35 i.e. 25/29% oil and 10% nitro.
For the Norvel 25 the Norvel 15 nva fits and makes this a good runner. Not a stunt run but fast and consistant..
Hope that this info is useful.
Dennis

RE: big mig .25 for flite streak?
 

Super helpful response, Dennis. Thanx a gallon,
M

RE: big mig .25 for flite streak?
 

I don't know if they changed it, but the original prop stud was kinda brittle. Broke a bunch of them just by overtightening. Didn't help the ones I didn't snap then by running them into other peoples airplanes. The Stainless bolt won't snap so quick. Used a BigMig in SLC for a while last year, did have the carb idle screw all the way in, but that wasn't keeping it all the way open, so I pushed the throttle open and bent the metal arm over so it don't close no more.

Lotsa power in that little engine, should be fun.

RE: big mig .25 for flite streak?
 

Yep, you can see from the attached pix with the original note, that bolt's snapped off in there. I'll bet the original owner over-tightened it, piled it into something, and it broke. And it musta struck dead head-on to the prop shaft, 'cause, otherwise, the motor looks brand new. Not a scratch.

And I do like your tip, about opening that throttle arm and then bending it over. Got it wired open now, but I surely hate to have bits of wire strung up on an engine, no matter how tight they look.

Thanx, Clean, for the hit,
M