B.J. Cicada build

[werowance]

keep the flux just to the local area as the solder will run where the flux is

,

Thanks Paul, yeah I know it was thick and spread out, I normally use a q-tip to apply it but as it was just a test piece I didn't bother running back in the house to get some, I just used the large brush that came in the can of flux. started to wipe some off with a paper towel, but again, just to lazy for a test piece. I will also probably use a small diameter piece of solder on the next one to.I will though be careful on the real piece when I get it ready. had heard that white out correction fluid was handy in that you could paint a ring around the part to keep the solder from flowing so far, have you ever heard of this or tried it?

 

[Swifty]

,
had heard that white out correction fluid was handy in that you could paint a ring around the part to keep the solder from flowing so far, have you ever heard of this or tried it?

I haven't tried the White out, but I know that Brian Rupnow is a great fan of using it, so it must work well.

Paul.

 

[werowance]

maybe that's where I saw or heard about it in one of his posts. will have to go back and see if I can find it.

 

[Brian Rupnow]

It shows it in my very recent carburetor build thread.

 

[werowance]

finally got some 12L14 large enough to cut the cylinder from. I love working with this stuff. while making the new one I found I had made a mistake on the old one and had the fins to close to the intake and exhaust holes:hDe:. I had forgot to subtract the diameter of the base flange from my measurements. this should make soldering the bung even easier on the new one. you can see in my picture of the old melted one compared to the new one the difference.
I also used a larger radius tip carbide insert and that gave a nice radius to the larger section between the base fin and the first cooling fin. I found those tips on ebay and they do seem to leave a much nicer finish than the sharper tipped ones.
didn't have time to put the cylinder in the rotary table to do the flats and drill the holes but did have time for a quick part, so I decided to make the jam nut for the carburetor. ended up taking longer on that because I ruined the threads on the first one. I used tap fluid on the first one and galled the threads up:wall:. the second one I remembered that brass should be cut dry so I tried tapping it dry and it turned out just fine. lesson learned I guess I should tap brass dry all the time?

pic 1:cylinder all blued up and on its arbor for the rotary table
pic 2: same just different angle
pic 3: old and new cylinder side by side to show my measurement mistake on the first one
pic 4: brass jam nut
pic 5 brass jam nut other side
pic 6 the new large nose radius carbide inserts
pic 7 large radius carbide next to normal sharp tip carbide. the black one is the new one

 

[werowance]

not able to be in the shop right now so I thought I'd do a little shopping for a prop. what size would you all recommend for it? is there a rule of thumb for the prop size? would you measure from center of crank to top of head or longer? when ordering, are props listed for example a 6 inch prop, would that be 3 inches from center of prop which makes a 6 inch over all length prop?

would you go for plastic or wood or does it matter?

would like to make my own but I think Ill start with a store bought one at first.

Bryan

 

[goldstar31]

I haven't tried the White out, but I know that Brian Rupnow is a great fan of using it, so it must work well.

Paul.

An HB or a B Pencil works well. All that happens is that it makes the part that doesn't want solder to be 'dirty' . Also works on soft solder but oddly, if you are gas welding with oxy/acetylene the carbon in the acetylene acts as a flux. If you are Mig/Mag weldingie Metal Inert Gas using Metal Active Gas system, carbon as CO2 becomes a shielding gas.:hDe:

 

[Swifty]

As far as I understand, props are always sized by their overall length and the pitch, ie, a 6 x 1 prop is 6 inches overall length with a 1" pitch per revolution of the prop. I have used plastic props as well as wooden props, but for display purposes only. I prefer the wooden props for display as they look a lot better.

Paul.

 

[goldstar31]

Paul is right about diameter and pitch and from what I recall, the jury is still out on which to make or buy.
Really, it depends on how capable your engine is and the task for which it is intended.

If my ancient memory is holding out for a while longer, you actually need a set of props and a home made rig as a dynanometer. If you are merely wanting to see the 'wheels go around' or to 'run in' your engine from new, I'd choose a large prop to get more leverage for flicking it over.

Others WILL be just as right-- and wrong.

Norman

 

[werowance]

If you are merely wanting to see the 'wheels go around' or to 'run in' your engine from new, I'd choose a large prop to get more leverage for flicking it over.

Yeah, that's pretty much it, just something to make the engine run and look good. ill not be putting it in anything other than a display case if it will run for me.

considering the engine from center line of crank shaft to top of cylinder is right at 2.1 inches high, would you go for about a 6 inch prop? or longer / shorter?

 

[werowance]

made some headway this weekend. almost finished the cylinder. made the head. started on compression screw and tommy bar. all I lack on the cylinder and head is to drill and tap the two 4-40 head screws.

On sheet 4 of these drawings :http://modelenginenews.org/plans/BJ_Cicada.pdf
i believe there is a mistake. the head shows to drill and tap for 10-24 compression screw. but when you look at the compression screw it shows 10-32. i went with 10-32 for both. this is a mistake in the drawings right?

the silver solder was almost a disaster again however I think I figured out my problem. in my test piece I did not use the arbor that I have been holding my real cylinders in. this arbor is a good slide fit to the bore of the cylinder. I believe this arbor has been leaching heat or taking much longer to heat up and thus the carb bung is over heating. i did manage to get it soldered and sort of made a mess of it but after some cleanup with file and sand paper it looks fine. may do a little more filing later.

i did not have any piano wire for the tommy bar on the compression screw so i chucked up my pencil grinder (diy tool post grinder) which fits my 3/4 boring bar holder perfectly. i ground down some drill rod i had to make the 3/32 tommy bar out of

here are some pics

1 - 3 are of the cylinder and head. just different angles
4 - 5 are the tommy bar being ground.

 

[werowance]

well, I have finished the contra piston and almost the piston, waiting on a reamer for the cross drill wrist pin.

been working on the carburetor parts and man, some of those drills are tiny. bought a set of pin chucks and they are not at all accurate, what do you guys hold those little tiny drills in?

here are some pics I have of what I have assembled so far.

 

[werowance]

my reamer arrived this weekend so I finished up the piston, this completes the main portion of the engine - I do still lack trimming the crank case on the sides for the mounting flanges however that can be done after I get a chance to see if it even runs which will be after I get the carb finished.

I also got a small Shars brand chuck last night and its wonderful for those little tiny drill bits.

I also learned a new trick (new to me) for center drilling brass. for some reason brass always wants to make even center drill bits walk off center a little whereas steel or aluminum doesn't seem to do that to me. but the trick I learned was to take my sharpest dead center and put it in the tail stock and push it in the end of the brass just to make a small center punch mark, then the center drill doesn't walk any more and where my dead centers are centered just as the drill would be it makes a perfectly centered dimple in the brass

so that trick combined with the new chuck has really helped me with the little itty bitty carb parts and drilling those little holes with pin drills

only picture I have today is of the completed piston.

 

[werowance]

3. You need a mix of Kerosene, Oil (usually castor), ether and possibly an ignition improver but not really needed for a display engine. Some suggested mixed diesel part way down this page. Glow fuel won't do.

http://colinusher.info/Model Aircraft/fuel.html

Jason, getting close enough to where I need to start ordering fuel mixing supplies, Kerosiene is no problem to source, but what about castor oil and ether? on ether can I just buy a can of starting fluid and spray it into a container and then put a lid on it so it doesn't evaporate? castor oil- you mean the stuff that they used to show on old television shows where the kid who was acting up would get a spoon full of castor oil as punishment? would I find that at a drug store?

Thanks
bryan

 

[goldstar31]

Castor oil? Medicinal stuff is too dear. I always used 'cow castor oil' which farmers used on beast as it was cheap(er) However, the paints and plastics industry used literally tons of it.


A little bit more is Castrol R oil which was the unmistakeable smell of old motor bikes and this was the Wakefield's trade name.

Norman

As this is a total loss oil, why not use sunflower oil?

 

[werowance]

Castrol r - like 2 stroke oil for dirt bikes and chain saws? if so then I can source that at the auto parts store no problem. sun flower oil? if that will work then I should be able to find that at the grocery store.

I don't plan on running this engine much. just to prove it works and then every now and then to show off (assuming it works) it will spend the rest of its life on the shelf as my first engine. (also assuming it runs).

now for the ether part. man I wish I still had access to the lab at school. they had quart bottles of the stuff. but cant seem to source a small amount anywhere on the internet. at least not without buying in quantities that a large business would use.

Bryan

 

[Jasonb]

Yes Castrol R as in performance 2-stroke oil which should be available from Bike, snowmobile, etc stores.

Ether is the hard one to get here now and sound like it is where you are too, its used in the manufacture of illigal drugs so they make it hard to get.

May be worth checking some of the RC aircraft stores to see if they can supply ready mixed for the small amount of running you will be doing.

 

[werowance]

Jason, I checked around on line and seems the way to get it now days and was actually suggested by fhs hobby fuels for ether was to buy John Deer starting fluid and get it out of the can that way. reading on other forums about it they are saying pretty much the same thing, John Deer or a quality starting fluid as it contains more ether and less aditives. take a mason jar, poke a hole in the lid, use a wd-40 straw in the aresol spray tip. spray the whole can out in the mason jar. replace lid with one that doesn't have a hole.

so I think ill do this formula - what do you all think

kerosein - about 40%
ether from john deer cans - about 35 % - read anything over 30 percent is a waste but considering john deer ether wont be pure I was going to up it to 35%
Castrol r - about 25 %

but if I keep messing up on cutting the venturi nipple ill never get this carb built to even need fuel.
tonight ill start the third attempt at the nipple. each one looks better than the first, almost had it last night and on the last drill I went to deep and ruined it. - again:wall: oh well 1/4 inch bras hex isn't terribly expensive and its itty bitty size so I guess I can afford to mess up a few more if I have to.

on the plus side, the needle valve, jam nut and gland nut all went very well. so only 4 more parts to make or re-make before I can test it. we get a long weekend this week from work so hopefully ill have lots of garage time this weekend.

 

[werowance]

Well only lack the main carb body. Wanted a change of pace something more fun without major attention to tolerance so I decided to make a fuel tank. Mostly scrap, the main body is from a scrap oxygen concentrator for people with breathing problems a friend brought me, the fuel nipple is from a piano that I'm not sure went through a flood or fire or both but a friend who did the cleanup brought me the wire and brass and scrapped the rest, the fuel filler was a very short piece of scrap 360 brass I had saved that was very hard to chuck up and last the end caps are from a scrap door kick plate that goes at the bottom of a fancy door that I cut out to fit. Then soldered it all together and lightly polishedView attachment ImageUploadedByModel Engines1421706630.450256.jpgView attachment ImageUploadedByModel Engines1421706642.648585.jpgView attachment ImageUploadedByModel Engines1421706734.382016.jpgView attachment ImageUploadedByModel Engines1421706743.944513.jpg

 

[Brian Rupnow]

Super nice work on the gas tank. Be proud!!!