Titan X50B new build w/ factory FBL conversion and MICROBEAST

[Bob O]

Maiden is planned for Wednesday.......low 60's and 10 to 15 mph wind. Should be a great day. That will give me tomorrow to give the heli a once over, balance the main blades, etc. I might be able to get some pics tomorrow depending upon how busy things get for me. Either way, Wednesday will be the day.

[Bob O]

Redid the throttle linkage (moved the ball out one hole) to get 100% travel adjust on each end.
Recalibrated the RevLimiter. Fired the engine up to make sure it would work before the maiden tomorrow. She's ready!!

[johnbs8]

GL Tomorrows weather looks awsome in the forecast.

[Bob O]

Flew three tanks yesterday. The weather was good, temp about 57*F and wind about 15 mph.

The first tank was used with approximate needle settings (7 gallons since new ring from last year) just to do basic tuning with the MICROBEAST. Started with the following:

B - Control behavior: Extreme
C - Swashplate - pitching up behavior: medium*
D - Tail - HeadingLock gain: very low
E - Stick deadband: 2*
F - Tail - torque precompensation (RevoMIX): off*
G - Cyclic response: normal*
H - Pitch boost: off*

All three Dials at default, tail gain at letter G, head speed around 2100 RPM. Setup menu point "J" was 6* and red LED (blue didn't come until 6.9*), collective pitch range set at 13*.

Having had the 600LE and Velocity 50 on the MB (both had the blue LED precisely at 6*), I had a good idea of what to expect for this first flight. I was pleasantly surprised when the heli responded fairly locked in for it's first flight with the basic settings.

Piro rate was quicker than with the other two helis, but faster with right rudder. Piro stops were fairly firm and reversals were very precise. Tail hold in fast backwards circles was a little soft. Tail hold in pitch pumps and climb outs was pretty good. Tail hold in 45 degree angle forward and backward flight was pretty good. There was very slight whipping while pirouetting in moderate to fast forward flight.

In fast forward flight, porpoising was very faint under collective pumps. Cyclic stops were failry firm in tic-tocs, although the flip and roll rates seemed slightly slower compared to the other two helis. Collective felt great compared to the other two helis, which were hyper-sensitive around center stick. The collective with this heli felt near perfect. Overall I felt reasonably connected to the heli. So I made a few adjustments after this flight.

B - Control behavior: left it the same
C - Swashplate - pitching up behavior: increased to high
D - Tail - HeadingLock gain: increased to low
E - Stick deadband: left it the same
F - Tail - torque precompensation (RevoMIX): left it the same
G - Cyclic response: left it the same
H - Pitch boost: left it the same

I raised the tail gain to letter "I", and turned down the endpoint for right rudder by 2 points. I also turned all three dials up one notch. I richened the mixture two clicks on the high needle due to a significant leaning out toward the end of the main tank.

The tail held very well in all aspects for the second flight. Piro rates for right and left rudder were equaled out, and stops were slightly more firm. The slight whipping in pirouettes during fast forward flight was gone. There was no kicking out of the tail at all during pitch pumps or climb-outs. Although I didn't do any big and fast tail down inverted funnels (my favorite maneuver), the tail on this heli felt better than both my previous nitro birds.

The slight porpoising in fast forward flight was gone as well. Cyclic stops felt the same as the first flight. There was no coasting, bouncing, or wobbling. More adjustments will be made on a different day. Being that I only had time for one more flight, I decided to leave the settings as they were so I could just fly and enjoy the heli on the third flight.

Now comes the weird part. The third flight started with a blown glow plug. The plug (OS-8) was new this season and only had today's two flights on it. No gasket sealer of any kind was used on the exhaust, and there was a perfect seal at the manifold. I ran it this way most of last year. So I put a new plug in and fired it up. The fuel filter was also new with this build.

Took off and proceeded to do some big air maneuvers, some fast passes, rainbows and lots of tic-tocs. I had the timer set for 6min 30sec. During the tic-tocs, which were about 20 feet high and some 40 feet out, my friend asked me if my motor was leaning out. I told him that it didn't feel like it was, but a few seconds later came the dry sound followed by a sharp increase in RPM. I immediately hit TH and auto'ed back in. Only 6 minutes had passed since I took off.

Upon landing, the engine was idling nicely. The header tank was full and there was about 1/2 inch of fuel in the main tank. I shut the engine down and checked out the fuel system and engine. Both main and header tank clunks were still attached, all lines attached with no leaks. The carb was still seated and snug, and the exhaust was still tight and without any signs of leaking.

The only things I didn't get to check were the glow plug to see if it had loosened (I doubt it), and the head bolts to see if they had loosened. There was no leakage or spray of fuel on the engine or head. Upon checking the back plate sensor, it appeared to be in the proper position. However, I didn't get to check that either to see if it was still sensing properly.

My initial thought was that the engine had leaned out badly, was sucking air, or something like that. After finding no problems with the fuel tank or lines, and no problems with the exhaust, I'm going to focus my attention on the back plate sensor. It just doesn't make sense that the engine leaned out after having richened it prior to this flight, and still having plenty of fuel left in the tank.

I won't be able to fly again until Friday or Saturday, so I'll have a look at things between now and then before I take her out for some more testing. I'll report back afterwards.

One last thing. There was about 1mm vertical play in the main shaft that I noticed when picking the heli up after the third flight. I'll be sure to adjust the main shaft locking collar before next time out.

Overall, I am very impressed with this heli. In the air it felt extremely light compared to my previous two. Further tweaking of the MB can only make it better! I plan on increasing the Cyclic response parameter next time out. I'm also going to increase endpoints for aileron an elevator by a couple of points to speed up the roll and flip rates a bit. If I can't get them to my liking, I'll switch to transmitter mode after that. Both previous birds were flown in the Extreme preset, which I liked a lot. We'll see what happens.

[DethWshBkr]

That play in the main shaft - I have the same thing, and I'm not flying her hard at all! I'm still breaking in the motor a little and nervous about flying it.

I did do a bunch of near full collective punch-outs, at about 65% throttle, and I definitely have some vertical play in the main shaft now. I read somewhere about a lower or upper bearing black failure somewhere, and I wonder if this slop is why that happened. Seems the upper bearing block is what takes the load.
I will try to remove my shaft completely, perhaps drill in two tiny "locating holes" in the main shaft for the set screws to go into, and put it all back together, because apparently the two set screws in there are slipping a little.

[Bob O]

Well, neither the 600N nor the Velocity 50 had dimples in the main shaft for the grub screws, and I never had an issue with them slipping that I recall. I used a Logo collar on the Velocity though, and the best that I can remember it had three grub screws. On the 600N I just used the stock collar.

I'll just loosen the screws and reposition the collar for no play. If that doesn't do it, I'll try a different locking collar (different design). Also, the lower bearing block can be subjected to as much stress as the upper depending upon how much inverted flying you do.

The one bearing block failure I saw a few weeks back was a plastic one, and I'm pretty sure it was the lower block that failed. I have the metal ones installed.

I was going over my heli today and most things checked out. The crank pin sensor was still sensing properly. Looking through the exhaust manifold, the piston, sleeve, and ring all looked normal. However, upon shining a flashlight into the fuel tank to examine the clunk, I saw that one of the little "bands" to secure the line to the nipples was off. Not knowing which one, I pulled the lines and found it was the one for the bung. The line was still attached though, and I inspected it very carefully for tear or cracks and it was in perfect shape. Note that this was new line used for this build.

Anyway, I took a pic to show the piece of tubing in the tank. The band on the clunk end of the line was intact, but I replaced them both anyway. I used regular silicone tubing for the bands this time. I also took the header tank off and will try a couple of flights with just the main tank and Fuel Magnet. I didn't use a header tank with either of my other nitro birds. BTW, when I had the fuel magnet out, I found out just how much fuel that thing can soak into it! It was just like a soaked kitchen sponge.........it was literally saturated with fuel.

There's no doubt that this "magnet" will soak up fuel being splashed around in the tank. I'll report back later this evening.

[Bob O]

Good news and bad.

The good news is that there were no fuel tank issues with just the main tank and Fuel Magnet. I actually like the cleaner look of not having a header tank so I'll likely leave it this way. Also the engine ran great.

Bad news is that when I hit stunt mode (100% flat throttle curve on the Limiter) on the first flight, the RPM went right through the roof. So I set up some basic throttle curves and Cyclic>Throttle mixes, and the engine ran fine. So basically the back plate sensor is bad.

Problem with that is it still senses the crank pin. Upon turning the crank over by hand and watching the sensor light on the receiver, it flashes with every revolution of the engine like it's supposed to. It's just that the receiver is not limiting.

Keep in mind that I had two flights without a problem on maiden day, and the Limiter seemed to fail during the third flight. Not sure what to think of that being that the sensor actually works. Maybe for some reason the failure can't be reproduced on the bench.

Anyway, I'm going to order a new sensor to see if that solves the problem. If it doesn't, it would seem that the Limiter function of the receiver is bad, which I hope isn't the case as I don't want to have to send it in for repair.

So until I get this issue straightened out, I'll be flying on curves again.

[NitroAl]

Have a look down the inlet nipple of the header tank and check for molding flash around the bottom of the nipple inside the tank. This has been known to cause issues in the past!
I doubt the leaning problem is the result of the main tank clunk sucking air if there is no air in the header tank so the most likely causes are a blocked pressure nipple, hole in pressure line or a restriction in one of the fuel lines or fittings!

To solve the end float in the main shaft I used a shim on top of the collar under the top bearing, I think from memory it was a TRex 700 spindle bearing spacer!

[Bob O]

Thanks for the info, Al.

However, I'm sure the problem is the back plate sensor due to today's flights. Using a flat 100% throttle curve and limiter/ Gov menu to control RPM, there was no control of RPM. Dropping the mid point of the throttle curve to 50 gave me a lower RPM. I can't find a new sensor lead anywhere, so I'll have to take a look at the one I have. It's possible that the sensor position just needs to be adjusted in the bracket, that would be great if that solved the problem. If not, I'll inspect the whole wire to see if there are any breaks, cuts. etc.

As far as the revving and leaning out from the other day, I'd have to say that was a combination of the sensor failure AND being lean on the H needle. Today there was gobs of power after setting the needles slightly rich from the previous outing.

[Bob O]

Found the problem. Now to find a replacement. They seem to be out of stock everywhere in the US.

[Bob O]

All I could find anywhere was this: SPMA9569 Aircraft Telemetry RPM Sensor and Bracket. It appears to be the same thing except for the connector, which I can take care of with my connector/crimp kit.

Horizon doesn't show the old style bracket and sensor being available until May or June, so I ordered this telemetry unit. I'll post once I get it and verify if it works or not.

[KouDy]

I am not sure what you are looking for but i can check around here if it's available and ship it to you if you want

[Bob O]

Thanks Kou, but I already have a part ordered. I also dug up my old/original sensor and will attempt to fix that. If the new one ends up working, and I can fix the original one, then I'll have a new one and a spare!

Thanks again!

[Bob O]

The replacement Spektrum "telemetry" sensor came today. Upon initial inspection it appears to be identical to the original backplate sensor, just with a different connector. Tonight is the start of four 12-hour midnights in a row.....ugh.

I'll post up some pics and such in a new thread next week.

[Bob O]

Finally got a day off!

I rigged up the Telemetry sensor today. Bench testing went well. I won't get to fly it for a few days due to the weather.

https://www.helifreak.com/showthread.php?t=399418

[Bob O]

Just thought I'd post pics I took of a few different FBL blades I've tried. I've also tried Radix and Align blades, but they were FB versions.

I don't fly Mavrikk anymore. Currently I have the Rail blades on my heli, but I'm going to swap them out for the Edge, which are my preferred brand.

[see_e_oh]

Hey Bob:

What size EDGE FBL blades are you running? 603? 623?

What's the recommended size for 0S55HZ Hyper?

[Bob O]

Originally Posted by see_e_oh

Hey Bob:

What size EDGE FBL blades are you running? 603? 623?

What's the recommended size for 0S55HZ Hyper?

Sorry, those are Edge 603. The Rails are 606 obviously, and the Mavrikk are 600mm.

Depends upon the heli. Guys flying Velocity 50's are using 623mm with the OS-55 and YS-56, but that heli has a longer boom than the X50. Although I didn't measure it, just eye-balling it made me not want to try longer blades with my new bird.

[see_e_oh]

Thanks Bob.

I've got the motor on a Raptor 50 using the EDGE 603's and they fly great.

Can't wait to get this X50 finished up!

[johnbs8]

ive been using 615mm blades and like the action im getting.615 to 620mm blades work fine on x50