Author Topic: Bi-Slob assembly (Read 1752 times)

Paul Smith · « **on:** October 29, 2008, 05:22:55 AM »

I won this Bi-Slob at the T&D. A big thank you to The Toronto Balsa Beavers for giving this airplane to me and to Mr. Brodak to donating it to the club.

While I do not not inhale ARF's, I decided to make an exception and puff just this one. I've always wanted to make a Dune ornithoper, so I modified this Slob into one.

The wings will remain pretty much stock. The fuselage and tail feathers were stripped of their low temp covering.

Job ONE was to plug the bolt holes with dowels and downsize the engine mount to take an LA 25. I've done this to so many old Fox 35 planes, I can do without the spice. The gap was narrowed with 1/16" plywood and doublers of the same material were added.

The gapping hole under the engine was planked over with 1/16" Balsa USA. Finally, the entire fuselage was covered with silver-gray silk. This was needed for fuel proofing and fibre strength.

The fin and stab were refinished with genuine Top Flite Super Monokote.

Paul Smith · « **Reply #1 on:** October 29, 2008, 05:44:52 AM »

I didn't fo-grap the fuel tank. It's just an old 3-ounce steel tank from my tank drawer, revented to fit the plane. I set it up with only two vents, feed to engine and muffler pressure. To fill it, I will have to disconnect both the feed and pressure lines, thereby warding off flooding during the refueling operation. The muffler pressure is used solely to prevent loss of fuel in the unusual Slob flight antic.

I built the tank into the plane. A no-no in the stunt world, I know. But due to the low airspeed, I don't expect any trouble. Worst case: I cut the silk and fix it.

The plane comes with pre-bent flap and flipper pushrods with no means of adjustment. I dealt with this by gluing in temporary blocks to hold the bellcrank level. Then the flap was centreed by jiggering the horn position. The elevator was blocked level with popsickle sticks. It was then positioned true by sliding it fore-and-aft a little.

Notes: a hardwood block was added make the bellcrank mount double-shear. Also, some triangle stock was added to align the tail fin. After installation of the top wing, the bellcrank blocks were pulled out.

don Burke · « **Reply #2 on:** October 29, 2008, 10:17:46 AM »

My Bi-Slob, built from a kit, had some reinforcement of the bellcrank platform, but it met it's demise after a WHATZIT manuever when the lines went slack. When it hit the ends of the lines again the entire bellcrank assembly pulled out through the side of the fuselage! Quite a mess, even destroyed the engine crankcase (LA25) on impact. The 1/16 fuselage sides were just not enough to take the load. If I build another I will add a plywood doubler to the inboard fuselage side top to bottom, and bulkheads above and below the bellcrank to spread the load to both sides, and I'll try to not do any more WHATZITs. Sure was fun to fly until the WHATZIT!

Paul Smith · « **Reply #3 on:** October 29, 2008, 02:06:17 PM »

Thank's the input. As far as the bellcrank mount goes, I've already crossed the Rubicon. I hope the extra piece I added transfers enough load to the upper wing saddle to get it done. Also, the silk on the fuselage is another step in the right direction.

Did you get in enough flights to pass judgment on the LA 25 as a prime mover?

Jim Kraft · « **Reply #4 on:** October 30, 2008, 10:00:13 AM »

Paul; I built a couple of Slobs a few years ago from Flying Models plans. Both of mine have Fox 35's and are a hoot to fly. I was out the other day with my oldest Fox installed, and the plug went south in the top of and inside loop. It was very windy, and the silly thing went straight in from about 35'. I went over to pick up the pieces and was amazed to find only a broken prop and the stab knocked loose. No other damage. I did use 1/32" ply doublers in mine.

don Burke · « **Reply #5 on:** October 30, 2008, 11:08:39 AM »

Re: LA25 suitablity

Had no problem whatsoever with the LA25, plenty of power, 9-4 APC, Powermaster 10% fuel. The crash was my fault not the engine's.

Paul Smith · « **Reply #6 on:** October 31, 2008, 02:25:56 PM »

A successful first day. Halloween in Michigan and a high of 72 degrees, sunny, and tolerable breeze.

I put in six fights with my new LA25-powerd BiSlob and it performed as advertized: Dead-stop hover, touch & goes, etc. Did a wingover, but no overhead eights. Upside right and upside down laps, OK. Since I traded the tailwheel for a stooge loop, I was able to "nail" the tail to the ground and do full-stop touch & goes.

Overheads will have to wait for a calmer day.

The propeller is a white Tornado 9/4 skuffed down to about 8-an-a-half.

john e. holliday · « **Reply #7 on:** November 01, 2008, 08:41:09 AM »

Glad to hear your Slob is flying. Per Jim Lee I am flying with 10-4 on a Fox 35 stunt. I have not went to the short lines yet as it flies great for me on 60 X .015. I think Jim says to go to 52 foot lines. Have fun, DOC Holliday

Allan Perret · « **Reply #8 on:** March 09, 2009, 06:18:25 AM »

I use 58 x .012 lines with a FP25 and 10-4 prop. The lighter lines give better feel while hovering when the tension is lower.

Paul Smith · « **Reply #9 on:** March 09, 2009, 08:42:36 AM »

I agree you could legally get by with lighter lines.

But the drag difference between .012 and ,015 isn't much at zero airspeed.

I'll have to check and see if I have scale fine enough to check the difference in mass.

john e. holliday · « **Reply #10 on:** March 13, 2009, 12:23:59 PM »

Stay with .015 lines and shorten them. DOC Holliday

Author Topic: Bi-Slob assembly (Read 1752 times)

Paul Smith

Bi-Slob assembly

Paul Smith

Re: Bi-Slob assembly

don Burke

Re: Bi-Slob assembly

Paul Smith

Re: Bi-Slob assembly

Jim Kraft

Re: Bi-Slob assembly

don Burke

Re: Bi-Slob assembly

Paul Smith

Re: Bi-Slob assembly

john e. holliday

Re: Bi-Slob assembly

Allan Perret

Re: Bi-Slob assembly

Paul Smith

Re: Bi-Slob assembly

john e. holliday

Re: Bi-Slob assembly