AA5BY

I just experienced an interesting series of events with my Ultrastick Lite. Two weeks ago, I experienced some throttle surging at full throttle and figured maybe dirty carb. Cleaned it before flying last week end with it happened again on the first flight. Then, I noted some control glitches with the antenna collapsed... so I packed it up and went home concluding that the throttle surges were servo glitches.

A ppm receiver was being used but I'd never had an issue with it during flight or the occasional powered up range test. I decided to trade it for a pcm receiver from another plane and while pulling the receiver, it hit me that I'd changed the antenna configuration up just before the problem started.

When building, I'd noted the solid wire pushrods for tail surfaces on the USL and ran the antenna wire to the end of the horizontal stab and had it like that for many months. The wire however was occasionally getting caught on the bench restrainer so was movedt under the fuselage.

When reinstalling the pcm receiver I went back to the original location and had no issues. Some caution might be needed on the USL regarding the antenna and those wire control linkages when using a gas engine.

3DDino

i wonder what you guys think if i put brillelli26ssr in USL
and still get unlimited vertical
thx

AA5BY

I'd think it would be a great engine choice for the USL. The G-20 provides unlimited vertical at 9,000 with a 16-6 APC @ 42 oz engine and ignition weight whereas the Brillelli is only 3 oz heavier but produces 9,600 with a 16-8 so it seems to me that it would be a great performer.

The USL has a lot of drag and a little more power isn't going to make it much faster and I'd not argue for more power at the cost of significant more weight considering the report that a G26 wouldn't yield unlimited vertical until weight was reduced by modifying to electronic ignition. The brilelli however fits the weight envelope well I would think.

And... I doubt you would have to add any tail weight. With a G-20 on very short standoffs, just long enough to extract the wires and fuel lines from the fire wall hole, my flight battery is just ahead of the servo tray and the fuel tank is 90 percent in the wing bay whereas you might find that a position just aft of the servo tray for the flight battery would compensate for the slightly greater engine weight and longer standoffs or one or both tail control servos might be installed aft.

If you go that direction... give us a report... I'm betting it would be good.

3DDino

roger that

pecapen

For seccure intall of a 26cc gas engine, should be necessari any modifications on fire wall?
Regards.

AA5BY

The USL has angle stock on the two sides to reinforce the fire wall... I've had no problems with the G-20 but it is a very smooth running gas engine. If concerned, it would not take much effort to add angle stock to the top and bottom and beef the fire wall a bit more.

Al Lewis

I believe if you jump over to the BCMA thread there may be a guy in there flying one on the BCMA 26cc. I bought a couple of these engines and they have great power. They're also light and have great after-market service.

Tweet

My Feedback: (1)

The BCMA only weights 36 ounces with the ignition and muffler. Given that light weight could you leave the servos for rudder and elevator in the stock location?

mmiller1

My Feedback: (75)

I have installed a SPE 26 on my UltraStikLite. The problem I encountered was how to get a fairly direct shot at the throttle arm on the engine. It is located on the underside of the Walbro Carb. I tried using goldenrod but the geometry did not work. So, I mounted the servo under the fuse with the majority of the servo just behind the firewall. That way I get a direct shot from servo arm to throttle arm. Someone said just turn the carb over. I does not appear as if that would work. This configuration seems to be working except for the fact that I can not seem to get the low and high ends tuned correctly. This is my first attempt with gas, so needless to say there is a learning curve taking place. I have read many additions to the gas forum but have not come across this topic. My idle was too high with the stick all the way back (even tried end point adj). The trottle arm was as far back as it could go. So, I next turned the low end adj. screw until the idle dropped down to a nice purr. However, when I advance the throttle I could not get the high end to open up. So I tried to adj. the high end screw and got the rpms up, but when I trottled back, the low end idle was way too high. So, if any of this sounds familiar and can offer some advise, that would be appreciated.
Tim in Tacoma

crazyjoseph

My Feedback: (3)

I have one with a ROTO 35 Its 4 years old now and is used for training . Great engine no deadsticks