Engine for Bi Slob

[Steve Dwyer]

No doubt a very old subject but will a OS FP 25 or OS LA 25 using a tongue muffler provide enough power vs a Fox 35?  There's not much room in there for anything larger with the 15 degree motor off set.

Steve

[Dan Berry]

Probably more power than it needs and probably harder to make work properly

[Dan McEntee]

   I think the traditional engine for the Slob is the Fox .35 Stunt, and some use the OS Max-S .35. They both do the 4-2 break well and that is kind of necessary I think to so the tricks it can do. I don't think I have ever heard of one being powered with a modern .25 but I guess anything is possible. I wouldn't vary too much from what it was originally designed with and for. It's been too successful for too long!
   Type at you later,
  Dan McEntee

[john e. holliday]

Might find some one who can make a head and shims to make the LA 25 do a 4-2 break.   Or set it just laean enough to get air borne and play with low pitch props.  I have a Bi-Slob that needs to fly.   

[Reptoid]

  The Bi-slob will surprise you. It is VERY draggy.600+ sq" and a very draggy box fuselage. The Fox 35 is borderline on power for it and to pull through overheads it needs diameter in the prop. We have flown them a lot and a modern 32-36 makes them fly very well. That way you can use a low pitch larger diameter propeller and smallish venturi making for excellent fuel draw and the reliability needed to avoid a flame out, which with a bi-slob is disaster.

[Dave Hull]

A Fox .35 or a Mickey .35 make it a Bi Slob. A little OS....makes it...something else?

Both the Fox and the Mickey fit in front with the engine offset specified. Just put a notch in the cowl for the needle and the tongue muffler.

If you have seen one set up for Slobbin' there is good amount of care to match the thrust (engine power for this discussion) to the draggy characteristics and the weight of the specific plane. That's what lets you hover and hang. I suppose any engine that allows you to get that match would work.

And get to flippin' and floppin'....

[john e. holliday]

I have a witness to the fact that my Bi-Slob does reverse wingovers into a light breeze very slowly.  In fact I kept waiting for it to come in at me.

[John Rist]

Go electric with an RC throttle.         

[kevin king]

I'd like to have a Bi Slob with a tuned pipe on it.

[gene poremba]

 About a year ago, i was asked by a local R/C club if i would be interested in introducing some new people to control line flying. Long story short, i took my Bi Slob to meet the challenge. I removed the Mc Coy 35 and put in an OS40fp with an R/C throttle that could be adjusted on the ground before each flight. We spent a full day flying with roughly 12 pilots getting their hands at flying controline. Some complete newbies, and some retreads. I short tanked it for the new people and adjusted the throttle accordingly to the pilots skill or lack of. I went thru about 2/3 of a gallon of fuel and ended up only breaking one prop all day. The plane took alot of rough tumbles, but held together. I have since flown it myself with the OS40LA and with the right throttle and prop combo its a blast to fly. Out of the 12 or so people that flew that day we only got a handfull of new controline flyers, but the club has since sponsored a controline event that drew 40 controline pilots from the surrounding area and has promised to do it again. We'll see....Gene

[Dennis Toth]

Steve,
All you need to do is install an adjustable leadout guide to allow you to add more yaw with the more powerful engine and it will do everything that it does on the FOX 35. If you look at the Carrier ships with the big sliders you can see that for very slow flight hanging on the prop you need yaw. Dan Banjoko (sp?) had a Ringmaster that he attached a third line to the tail and would pull that in and be able to do the fan dance just like the Bi Slob just by yawing the ship.

Best,  DennisT

[peabody]

Dennis and I sat through annual dissertations from Tom Neibuhr about the Bi Slob. Tom knew the designer and, I believe, inked the plans.
Tom swore that an unmuffled Fox 35 was the ONLY power to use.
And a "standard vent" tank
And a 10 X 6 EW Rev Up...

His was the first I saw and it did all the tricks.

[Steve Dwyer]

A Fox 35 it is then, what is the recommended size prop?  Another question, what have builders used for the outer wing struts 1/8" plywood or balsa, it's not defined on the plans.

Thanks,

Steve

[Steve Dwyer]

Also, I forgot, is weight necessary in the outer wing, if so how much?  It is also not specified in the Brodak plans.

Steve

[Joe Gilbert]

10x6 top flight plastic , boil the Heck out of then.  I liked the 10x6 topflight wood but you better buy by dozen if you fly a bi slob like they are meant to be flown. When you are tail dragging it now and again will you will end up on your top wing  and breaking a wood prop.  Great fun airplane made just for showing off.

[Dave Hull]

On my pre-Brodak BiSlob, built from the plans by designer Ron Pavloer, it has 1/8" balsa wingtip struts. Firm wood, with eyelets inserted for the leadout guide. I think the plans listed balsa, or to use liteply as an alternative. The plans are stashed away somewhere, so I can't immediately confirm this.

You're gonna need some tip weight! Again, without the plans handy, I'm not positive how much I added but I think it was something like 1/2 oz. in both outboard wingtips. FIRMLY glued in place.

Dave