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Archive for May, 2015
Posted by dmrcflyr2 | May 30, 2015 @ 02:04 PM | 4,478 Views
I was out last evening running about the 8th break-in tank through this engine when a scary thing happened. The engine just stopped while running at about 6000 RPM. Died, stopped. I had been monitoring the head temps and they were fine at around 175 each.

After it stopped it felt very tight when I turned the prop. Oh crap, what have I done? Well I immediately took it off the stand and brought it inside to cool down. After it cooled it still did not turn over freely. I did not feel or hear any grinding noises. I injected some Marvel Mystery oil into the port at the bottom of the crankcase to see if that helped things at all; it did not. I don't know if the front bearing let go or what, but there was one thing for sure, I wouldn't know until I took her apart.

So the disassembly begins. I took it apart with the back of the engine facing me and I kept all left and right side parts separate. I pulled the heads off and the pistons look just like new still. The valves look great. I had to pull the piston wrist pins and the piston heads off to get the connecting rods out. After each part removal I tried to turn the engine over to see exactly which part is causing the drag.

I found it. The right timing gear and cover came off and the engine freed up. Wow this is odd. The timing gear seemed to be somewhat seized on the shaft. It was quite hard to turn the gear but as soon as I loosened the set screw holding the shaft in place the timing gear began to turn...Continue Reading
Posted by dmrcflyr2 | May 23, 2015 @ 12:19 PM | 4,460 Views
After almost 27 years of patiently waiting to be run, this engine waits no more. I secured it to the stand and took it out for its first runs. The first run/tank went very fast due to the extremely rich setting. Heck I almost think more fuel was spraying out of it than was burning. I started with both needles at 3 full turns open, but almost immediately had to begin to close them up so it would run.

It was so rich most of the tank had to be run with the ignitors on. In fact as soon as I removed the one from the right cylinder it died and would not re-fire even when I put it back on. There are a few seconds of it just pumping fuel out before I killed the engine.

The restart I leaned a bit more so it would finish up without the ignitors on. I let it cool for about 15 -20 minutes while I topped off my ignitors again.

The second tank it started on the first flip already. I have run 3 tanks through it now but only shot videos of the first two tanks. It is well on its way to break-in.

FA-90T 1st run EVER. (1 min 27 sec)

FA 90T End of 1st run tank (0 min 45 sec)
...Continue Reading
Posted by dmrcflyr2 | May 21, 2015 @ 05:57 PM | 5,006 Views
This is the first ARF I have purchased from Value Hobby; I have bought servos from them but that is it. The price of their ARF's are very attractive and just beg you to take a chance on them. I have been eyeing several of thier airplanes for years but never pulled the trigger on one until now. I had been searching and thinking of the type of airplane to test fly my new twin cylinder engines on. The size, nose profile, and overall flight charateristics of the 'Stik' type airplanes were the deciding features for me. I have never owned or flown a 'Stik' before so this should be very fun.

The box arrived undamaged and the opening begins. I immediately found ONE of the reasons these ARF's are so inexpensive. They are not packaged in full color boxes as most kits/ARF's are. In fact I thought it was triple boxed, but in fact it was only double boxed. The inner box was just as plain as the outer; and as in good of condition too. ABout the only lettering on the boxes are the words "Made in China". What? I thought for sure these were out of Vietnam, but I guess not.

Once the box was opened I was pleased to see all subassemblies were individually bagged and nicely taped in place to keep them from shifting during transport. I removed each item and gave it a brief inspection. It was not my intention to begin building this tonight so further unwrapping was somewhat unnecessary. I did unbag the main section of the 2 piece fuselage. I wanted to set my Saito FA-...Continue Reading
Posted by dmrcflyr2 | May 20, 2015 @ 08:15 PM | 4,522 Views
It cost me several other engines but I think it was worth it now that she is here. I have scored the second Saito twin in a month. The FA-90T arrived at the front door today and man is she beautiful! This engine is the perfect compliment to the 80T. Granted it is not much of an increase in displacement but they have over 25 common parts. They also share the exact same mount/mounting dimensions meaning they will be an easy swap out of the same airplane.

At a few feet they look nearly identical but there is one major difference, the heads. The 80T has a two piece head while the 90T has the modern and currrent integrated cylinder head. I really doubt there is any difference in the carbs bodies. I am unsure how long the production run for the 90T was but the 80T was a very short 2 years. I think this is one reason you never see it mentioned in any manuals or the alpha engine codes guide.

So the first thing I did after opening the box was to remove the valve covers and check the valve lash. Two were out of spec and they were quickly reset. A few drops of oil on the rocker arm pivots and cover screw holes and back together it went. This 90T is NIB; it has never seen a drop of fuel. That is going to change this weekend though. I plan to begin the break-in process ASAP. No, no, no, I'm not keeping this a museum piece. It will be in the air very soon. In fact my test bed for these engines is due to arrive tomorrow as well, a Value Hobby Easy Stik 60.
Posted by dmrcflyr2 | May 08, 2015 @ 07:08 PM | 4,192 Views
So I started out with a Master Airscrew 14x6, the glow plugs that came in the engine, 10% Omega fuel. After prime the engine fired on the very first flip!! Being my first twin I was learning on the fly what it should sound like, what happens when a cylinder drops out, etc. It seems the engine likes the pressure tap on the left cylinder. ( I am referencing left/right from behind the engine) Anyway with setup as above I was able to tune it to nearly 8000RPM WOT. I could not get any more than that out of it for fear of leaning it too much. I did shut down the left cylinder once by leaning too much.

After the first two runs I changed 3 things.
1. Propeller from MA 14x6 to TF 13x6
2. Plugs: unknown plugs that came in the engine to Hangar 9 Super Plug
3. Installed a header from another Saito on the right hand cylinder for pressure tap. The original runs the pressure fitting was on the left cylinder.

I had a heck of a time getting it to start and run after these changes. WTH??? So I moved the pressure tap header back to the left side and I was finally able to get it started and running again. This really does not make any sense to me. But in the first video above, I did remove the pressure line once and it immediately dropped the left cyclinder.

Seeing as I am still very green to running twins, I am unsure what to make of this. it is also a bit difficult for me to know how to tune each carb. You can see in the videos I was using an IR temp sensor to read the head...Continue Reading
Posted by dmrcflyr2 | May 05, 2015 @ 06:20 PM | 5,026 Views
I realized one of my RC dreams! I have acquired a Saito twin, more specifically the FA-80T MKII. The FA-80T was the first twin cylinder engine that Saito mass produced. The MKI was introduced in 1981 and featured a singe carb. It was soon determined that the single carb was in adequate and the MKII with dual carbs was released. Basically they added the dual carb and designated it the MKII in 1982. This engine was only produced until 1983 when it was replaced with the FA-90T.

The 80T also has a two piece head assembly as opposed to the most common feature of Saito engines, the single integrated cylinder head. The 2 piece head has an advantage for me, which is the ability to remove and inspect the valves without completely tearing down the engine. A task I did last night when trying to determine approximately how much run time this engine has. My best guess is 1 gallon or less, but it is used.

This is not going to be a display only engine. It will be powering an airplane possibly this year and running even sooner. However, I am making the preparations to get it running this weekend if not sooner. I have a PSP Mfg. test stand with the back mount adapter. Tonight I drilled holes for the engine and throttle arm....Continue Reading