Space Bug Jr. - Trying to determine just how stupid I want to get

Bob, I’ve made the heads of screws smaller for PeeWee’s …. I drilled a hole in a block of wood about the diameter of the screw but only deep enough so about a 1/4” of the screw and head is out…. Then used the screwdriver to hold it down and turn it while filing the head diameter down…You could probably also chuck them in a Dremel and turn them down…. I see a few parts show up on the bay from time to time… I bet a crankshaft will eventually….Nice to see these old beaters come back

Ken, Mudhen pm'd me reminding me that the case is from a Space Bug, not the Jr. I noticed it and thought it odd but I didn't follow-up. Thanks Mud for keeping me honest.

Robert, I just chuck them up tightly in a drill press and hold a fine file against the spinning head until it's the diameter that I need, then polish with some fine steel wool.

But, you have jogged me back about 70 years to my Space Bug Jr. days and gotten me interested in them all over again. I loved seeing you run that engine!!!!

While looking for crankshafts and flywheels this popped up. Should be here next week.



Also this, helps with the flywheel question.

Glad you are enjoying the rekindled interests on SBJ’s Bob… Me too!!…I just enjoy running the thing…You’re boat will be pretty cool with one growling inside!!….Some more fuel for the fire  

Wow - Two minutes + with side mount needle. I'm dizzy seeing my Scientific Walt Musciano "Little Bipe" being hauled around the circle back in 1953 by it. Still have the plans but the plane is long gone. I believe it and the engine is laying in a tree in Raymond NH after on a whim I just let it go one day. 13/14 year olds have no sense.



BTW, Your Surf Skimmer is going to have company.

BTW, Your Surf Skimmer is going to have company.

That’s great Bob…. A pair of them will be good together… Any plans to make it different?… Paint job?… I’m liking your boat(s) project    

Jacob, If you do pull the trigger on making reeds here’s what I found on mine that may or may not be helpful… Just information…. The reed closest to the tank is .001” thick…. The forward reed is .002”…. I’ve read somewhere that they will run OK on one reed but don’t remember which one… Probably the thin one….Others with more SBJ experience  may know ….

rdw777 wrote:BTW, Your Surf Skimmer is going to have company.

That’s great Bob…. A pair of them will be good together… Any plans to make it different?… Paint job?… I’m liking your boat(s) project    

….

Label it "Experimental" because I have no idea what's going to become of it. It will feature a SB Jr. though.

I'm not entirely new to boats. I had given this one to my son, then I wanted it back. He shipped it to "professionally packed" by a UPS store and it got smashed. I rebuilt it. Really neat, someone other than me built it. R/C with a fishing pole that really worked. Servo controlled motor that would dole out line then pull it back in. I sold the darned thing when we moved up here from Florida. One of my BIG regrets.

That was a really pretty boat Bob…. Would be perfect to cruise around in that pond you have….  I’ve never seen one with a fishing rig before, Very innovative!!…. I’ve had a few boats too, Raced them in early 80’s…. A Prather 31” deep vee with K&B 3.5 with tuned pipe for A mono class and a 36” shovel nose hydro with K&B marine.40 for Sport.40 class…. Was fun for a few years but expensive to stay competitive…

I may have come up with a U-joint for Surf Skimmer so I made one up in Wood Bee machine shop for test…...Best I remember the drive shaft is piece of rod with 2-56 threaded end for the prop…I have some Du-Bro 2-56 control rods that are about the same thing …. I took a couple of pieces of telescoping brass tubing and reamed the smaller one to fit the Du-Bro rod…. Then cross drilled both to accept a piece of .045 music wire to engage the Cox prop nut intended for a soft spinner….Would need to be soldered up to hold it together…. Then a piece of fuel tube in the front to help keep it centered in the nut…

The only soldering you would need to do is the last joint from the U-Joint to the boat’s drive shaft…. A tight fitting piece of fuel tube and a washer could be installed on the drive shat next to the boat’s shaft tube to keep the U-Joint engaged with the drive nut….

If you think this could work I’ll make up a couple and send them…. Also need to confirm the boat’s drive shat is the same as my Du-Bro rod…(.070”)… or whatever size it is…

Thanks Robert I think it would work and I would like to give it a try. The SB JR.s drive shaft takes a 5/40 nut.

I did try that fishing line in the pond behind our Florida home. It was a big boat and could probably handle any fish in that pond, but there were also alligators in there too.

You bet, Will make a couple up   …. The photo shows the front end of SBJ with the 5-40 nut on… I happen to have one …. I tried to scheme out a flywheel but no bueno…. Maybe a local machine shop could make them…

I’ve heard of guys hauling out their bait and dropping it with a rc boat… Might be a fun project….When I was a kid there were a couple of guys would take their bait out in a row boat and monitor several rigs all night at that little lake that I fly nearby…. They pulled out some really big Yellow Cats….

From the Nautical division of Wood Bee machine…. I put them together with 95/5 solder….
I’ll send some 60/40 which has a lower melting point to lessen the chance to disturb the main joints…

Thanks Robert,  but I can no longer solder.  To see me try is comical, a length of solder in one hand a soldering iron in the other both vibrating to the tune of the Flight of the Bumble Bee...........thankfully my son is skilled.  Six years in the Navy as an Aviation Electronics Technician maintaining some of the Navy's most advanced electronics gear made him that way.  

But...........I can still swing a chain saw and do some other things.  I chucked the 2/56 Phillips in my drill press and turned it down with a fine toothed file held against it while spinning.  Easy.  Dealing with the nut, not so.  Thought I could get by with filing off just one flat, looks to need two to lay flat.  




The cylinder is going to need some work.  I don't even know if it will hold compression.......no crankshaft to test it with.  But Mudhen.....bless him is sending me one.  Mud has helped me save many of my projects in the past.  And just as an aside, he PM'd me letting me know that the crankcase is actually a Space Bug case, not a Space Bug Jr.  He could have just as well replied on my thread but chose to PM avoiding exposing me as the dummy that I really am about this stuff.  

The dummy and still learning...........Bob aka batjac

Nice going Bob, also didn't realize that the Jr. has a crankcase bronze bushing cast or pressed into it. This is explains how Cox could get away with the thinner nose. I gather that changes in aluminum to grades stronger led Leroy Cox to dispense with the bronze bushing and allow the crankshaft to spin in its native aluminum nose bore when he went to the more modern screw machines.

True ingenious, keep the quality up and reduce costs to put his products in front of the competition.

And, it is fantastic how @mudhen is supporting you in your refurbishment work of an old, classic engine to make it a runner.

I can see with a little further work on the plier damaged cylinder cooling fins, that it will be far less noticeable. However, if it winds up sporting a more modern cylinder that may be a little less than period correct but still a runner, I think you will still have a winner.

It's going to work repairing the hogged out drilled out case threads. (See correction below)

Cleaned out the gasket with a 5/64th so the machine screw wouldn't bind, turned the head down on the long 2/56 Phillips and filed half off the nut to fit flat against the case.




Test fit.







Next clean up and reblue the cylinder then wait for Mud's parts which are already in the mail.  If the stars align I will add a picture of it running in the future.  (I can't do video)

I still need to cut off the bitter ends with a Dremel cut-off disk.  Better left to Marks steady hands.

EDIT - CORRECTON!!!!!

Actually it's the Space Bugs case that is bushed, not the Space Bug Jr.  Never doubt the Mudhen

I took a SB Jr. apart just to check.  



As I have been incorrectly thinking all along that the SB Jr.s threads were hogged out, they are not.  Actually the case screws enter from the front of the case of the Space Bug not the back.

I think it important that I repeat this before I send someone astray......  

EDIT - CORRECTON!!!!!

Actually it's the Space Bugs case that is bushed, not the Space Bug Jr.  Never doubt the Mudhen

I took a SB Jr. apart just to check.  



As I have been incorrectly thinking all along that the SB Jr.s case threads were hogged out, they are not.  Actually the case screws enter from the front of the case of the Space Bug not the back therefor they were never threaded. But my fix works just the same.

Very kind for @mudhen to send the parts you need…. A lot of folks want to see your engine and boat running!! …. Made up a couple partial 2-56 hardware kits … Went into the mail today…I only had one of the Cox 5-40 to prop nut to engage the U-joint  but I bet you may have another…..

Got the second boat today missing the engine. Box keeps saying engine mounted in place, but I'm not seeing that. The mount isn't even punched out.








I'm thinking sand the hull, several coats sanding sealer, gloss white aerosal with one of Levents decals on the nose. Deck, poly and leave as is or paint red. Red tanked Space Bug Jr. power.

I got my courage up this afternoon and using a dremel with a cut-off disk removed those ends from the case bolts.  Only nicked the case three times out of four.  





I got those repro Space Bug/Space Bug Jr. reeds in, good quality nicely cut.  I also chucked up the glow head/cylinder in the drill press and using file/crocus cloth/ fine steel wool got most of the tool marks out.  Then Gun blue/Marvel mystery Oil.  Original SB SB Jr. cylinder and glow head.  
 



After I see if this thing will run, I will just swap the SB cylinder and head over to the SB Jr. case and have one authentic SB Jr. and one hybrid.  

Check out the case, someone filed off the cast in reinforcements.

Edit add.  This is a little crazy but I went back in my ebay history and found those parts.  Paid $18 for them Sept 3 2022.  ebays thrumbnail, rest slipped off the internet.

Looks like it’s coming together Bob, Just need for the crankshaft to come in…..I don’t know if SBJ’s had a venturi O ring gasket like a Bee…. Maybe someone that knows will comment?….. I made one for mine anyway from a thin slice of fuel tubing …. Or maybe a Bee O ring will fit…. That and some tank sealing finally got it running good after a couple of attempts…..I like the idea of an original and a hybrid…. You’ll be more likely just run the hybrid just for fun….Well, maybe both just for fun…

Got it today Robert. Beautiful.



These pages do not show a venturi gasket, but they list the fuel tank as an assembly so who knows. What is interesting to me is that they show both a spinner (MECOA reproduces) and a prop nut/washer. The SB Jr. that I just received has the washer and the nut, but the nut is vintage so I believe they are original to that engine.

Mud says to use a gasket so I stuck one on there. (New to me in the box SB JR.) Will do the same for the made up SB Jr.



But first I gave it an alcohol bath and cleaned up the case screws and needle.