hrrcflyer

YEAH!!! It's great to see this thread open again. I was starting to go through withdrawls....

8178

My Feedback: (17)

After giving the engine choice more thought I decided to tear down the engine that I tested for the Blue Angel and install one of my Nelson liners and pistons. The aluminum chrome Nelson liner is almost two ounces lighter than the stock ABC OS liner and has improved porting. That may result in an ounce or so less tail ballast too! While I had it apart I decided to replace the bearings because even though they felt and sounded good they didn’t look very good on the outside.

I expect most of you following this thread are very experienced at doing engine rebuilds but I thought I’d share my approach to the process.

My usual process is to remove the head (need to use an Allen wrench that is in like new condition to fit the bolts), remove the pump and drive washer. If the sleeve is stuck tight leave the drive washer on and install the prop. Insert a small piece of plywood between the top of the piston and the exhaust port. Turn the prop with a light force so the piston contacts the plywood and gently push the sleeve up.

After the sleeve is out turn the crank to top dead center and pull back on the rod with your finger. The piston should move to the back of the case, the rod should slide back on the connecting rod and the rod should almost fall off the crank shaft crank pin. Sometimes gunk can build up on the connecting rod preventing the rod from sliding all the way to the inside of the piston. Believe it or not, the professional engine rebuilders that I have talked to use a little heat from a propane torch on the bottom side of the piston through the back of the engine to free the rod. It sounds brutal but it has worked for me many times without any negative results. Just be careful with the heat.

Next I put the engine in an oven set to 350 degrees and let it heat for ten minutes or less. I remove the engine and hold it in a small towel and slap the back of the engine down on a block of would that is covered with a towel. Be careful. 350 degrees is darn hot!! With a good hard rap the crank should move back taking the back bearing along with it. Once the crank gets to the back of the case it should easily slide out with the bearing and you should be able to slide the back bearing off the crank shaft with a little force. I accomplish this by tapping the nose of the crank shaft on a piece of wood.

While the case is still hot I use a ½ inch dowel to push the front bearing out by tapping the case down with the dowel held against a hard surface.

After I get everything apart I clean up the case and head with Dawn Power Dissolver. Be careful that you do not leave the Dawn on the parts very long or it may tarnish the aluminum. At any rate, if it does get tarnished you can use Twinkle brand copper cream and a tooth brush to gently scrub the case and it will look like new. It takes a good bit of scrubbing and washing with hot water but the results are pretty impressive.

I do not mess with the pump other than clean it with fuel.

See images below to view the process and the images of the Nelson piston and liner kit. Unlike the OS piston the Nelson piston does not have an arrow on top pointing to the exhaust port and can be installed on the rod either way.

My new bearings are on their way from Boca Bearing and I will cover the assembly shortly.

To be continued…

8178

My Feedback: (17)

The weight is as follows with everything installed and if it turns out I do not need to add tail ballast:

7.5 pounds complete without pipe and header.
7.9 pounds with header and pipe

It should come out almost 2 ounces lighter when I install the engine with the Nelson liner set.

dhal22

sometimes used is better than new. [sm=what_smile.gif]

david

rainedave

My Feedback: (1)

I love restoring used engines and I've done a dozen or so over the last several months that I've picked up cheap at auction. I will vouch for the copper cream; it works like magic!

8178, one thing I do different - and this is just my preference - is to remove the crank before heating the case and bearings in the oven. I find it a lot easier to get rear bearings out of a case than trying to get them off of a crankshaft. The crank and the bearing's inner race are both steel and expand around the same amount, but the aluminum case will expand more than the bearing's outer race. So, they usually fall out after heating in the oven. This is more of an issue with older engines with lots of castor varnish inside.

Just to show you how well the copper cream and Dawn Power Dissolver work, I bought this engine for $23 off *bay. It was covered with black carbon and castor varnish. New ring, conrod, bearings, gaskets and O-ring and it's like a new engine (I did buy the muffler from Ken Enya new).

David

alcarafa

It's good to see this thread open again, over 65,000 views was worth it and see 8178 outstanding job going on !!!!

8178

My Feedback: (17)

The Boca bearings arrived today so I reassembled the engine. The engine with the Nelson liner/piston installed is a little over 1.5 ounces lighter than the stock ABC liner/piston configuration. Pretty decent for a used engine.

To be continued…

8178

My Feedback: (17)

OK, aircraft weight and balance exercise. My pipe is 27.5” long from the header to the tip of the pipe and weighs 7 ounces. The pipe spans the desired CG point on the aircraft. I installed the header and pipe and marked the aircraft CG point on the pipe and then removed the pipe from the aircraft. I then found the balance point on the pipe and header and discovered that it is 2” forward of the desired aircraft CG I marked on the pipe. So the pipe is exerting two inches more of its weight ahead of the aircraft CG. 7 ounces divided by 27.5” = .2545 ounces per inch. The pipe has 2” of its weight ahead of the desired aircraft GC resulting in .5090 ounces of weight ahead of the aircraft CG. Does that sound correct?

To be continued…

rainedave

My Feedback: (1)

How much does the pipe clamp hardware weigh and will it be behind the CG mark on the pipe? That could cancel it out.

David

8178

My Feedback: (17)

The mounting hardware stayed on the airframe.

vasek

My Feedback: (4)

I get PMs regarding the Blue Angel kit from Germany so here's the link:

http://shop.wega-sunshine.com/index....d83ad9ea7e7325

V.

8178

My Feedback: (17)

Got the gear strut flats ground for the axel and strut bolts. For some reason I just hate doing it but it is a must do to keep the strut parts locked together in the correct position.

I’m just a tad nose heavy on the recommended CG point and I’m not going to change it with tail ballast. From my calculations on the swept wing the recommended CG point is at 33% of the Mean Aerodynamic Cord (MAC). My CG will be at about 30% of the MAC and I’m OK with that rather than adding ballast. I may change my mind after I fly it for awile.

To be continued…

WEDJ

A 3% difference is hardly worth mentioning.

As you fly it, like all trimming procedures, you will look at the up/down lines, ability to snap, and many other factors to determine where you are comfortable with the CG.

Flying is the ultimate test. Post video, please!!!

8178

My Feedback: (17)

I test ran the rebuilt engine today and after about 16 oz of fuel it was turning 10.4 K RPM a couple of times when I leaned it out a little. Didn’t want to peek it up too much but also not run it rich with a new AAC liner and piston. My pipe length is 18” from the center of the glow plug to widest spot in the pipe which I believe is a good starting point for the pipe length when running an APC 12 -10W. Looks like I picked up 300 RPMs with the new bearings and Nelson sleeve/piston set. The pump and carb are working great with a good idle and smooth transition to full RPM. I expect with some more running the RPMs will pick up some as the engine still has a pretty good squeak as the piston moves through the upper part of the cylinder. The only significant event during the test was when a curious wasp got a little too close to the front of the prop and I got a face full of wasp parts! Ugh!!

Next step was setting up the fuel lines. I like to put a piece of fuel tubing over the end of the lines to keep them in place. I open the loop with a hemostat and slip the line trough the loop. It’s kind of tricky process but not bad after you figure out how to do it. It is pretty tight behind the engine for the lines but I think I got everything in without any line kinks. We will know soon! The brass U is a part I made for the Tiporare so I borrowed it for the Blue Angel. The top line is removed for fueling along with the vent check valve on the vent line. The black thing on the engine fuel supply line is a fuel filter with a piece of heat shrink on it to prevent it from making metal to metal contact on the engine. The check valve keeps the vent line from dribbling fuel and loss of fuel at various flight attitudes and keeps the airframe a little cleaner.

Not much left to do now. It is a little heavy on the right side even though I used my heaviest balsa on the left wing to offset the weight of the side mounted engine and pipe. I’m going to add a smidge of lead in the left wing to fix that. Got to glue the rudder hinges and check and adjust the control throws for final trim.

To be continued…

rainedave

My Feedback: (1)

Very nice! How are you routing your rx antenna? (I ask because I flew a new plane a few weeks ago with it neatly tucked beside the rx with the twist tie still on it).[X(][X(][X(]

David

8178

My Feedback: (17)

Yikes! Early in the build I installed an outer Nyrod along the top of the fuse that goes all the way back to the tail above the stab. The antenna is in the tube with a piece of masking tape across it at the front of the tube to keep it in place.

dhal22

a couple of the older flyers at my club have mightily denounced antennae wires inside the fuse. i am glad to see others using this method even if some leave the wire still folded with a twist tie.[sm=what_smile.gif]

david

rainedave

My Feedback: (1)

Well, it wasn't on purpose.

Atlanta 60

My Feedback: (18)

Prior to switching over to 2.4 my Helicopter guru buddies use to fly with the antenna wrapped and tied off around one skid...Now they got those new receivers with little whisker antennas...

8178

My Feedback: (17)

I’ve been putting my antennas inside my fuselages for decades and haven’t had any problems yet. I expect certain types of metallic coverings and paint could be a problem but that would be expected. One thing that people may not think about is that the antenna is pretty well protected when it is inside the fuselage compared to when it is flopping around on the outside.

8178

My Feedback: (17)

Making good progress. Glued the rudder hinges and added a little over ½ ounce of lead to the left wing tip to offset the weight of the pipe and side mounted engine.

To be continued…

ChrisMH

Gorgeous! I hope you are able to take video of the maiden.

I feel like I have been following this thread for years now...

8178

My Feedback: (17)

The Blue Angel is ready to fly! Just need some good weather and it will fly soon.

dhal22

it was so windy today at GMA after 1 flight with an extra hard landing i called it quits. it has been a rough spring flying wise in the Atlanta area with the cold, rain and wind.

david

alcarafa

MAYBE YOU SHOULD UPLOAD A VIDEO OF THE FINISHED BLUE ANGEL BEFORE THE MAIDEN FLIGHT, WHAT ABOUT VIDEO SHOWING ALL THE SETUP'S AND GORGEOUS PAINT FINISH YOU DID?

ABSOLUTELY A FANTASTIC JOB YOU ' VE DONE , CONGRATULATIONS WITH THE END OF YOUR BUILDING PROJECT.

REGARDS.
RAFA