I have been flying a Multiplex microJET lately. It is fast, a very smooth flyer and gets really small in an eyeblink. It has a long nose, big leading edge extension (LEX) and a almost a zero sweep (mac) outer panel. I noticed an interesting thing yesterday. During the later stages of the battery condition I fed in back stick until I had full aft stick. The airplane was flying level and completely steerable with the "ailevators".

However there was a small but noticeable (if you looked close enough) oscillation in the pitch attitude of the airplane that also showed up as an oscillation of the sound of the motor (very noticeable and same frequency as pitch bobble). It would appear to be the inner section of the wing going through an airflow separation and reattachment and which showed up as a flow difference at the pusher prop. If the inner section were staying attached and the outer panel separating then the airplane would bobble without the sound variation.

As soon as the new wears off I am thinking of trying some strakes, vortex generators, small fixed inner LE slat perhaps, and see if this characteristics can be modified.

Unlike a lot of things we do to models where we have no way of measuring if the mods were successful, at least the sound gives an indication of whether or not the mods would be workable.

I do recommend the microJET as a really fun airplane. I have a mechanical heart valve that you can hear as a click when there is no other sound around. I noticed a very rapid increase in click rate while flying the airplane, it is a real adrenalin maker.

Neat plane:

http://multiplexusa.com/models/ParkFliers/Microjet.htm

I'm getting to where I enjoy flying small, easy-to-transport planes instead of my big, "serious" aircraft. My Lazy Bee and Zagi wing sloper are fun!

--Bill

I've been experimenting on a similar little e-foamie myself. It's the firebat from Tower. Mine also makes prop noise when stalled. Since I'm working on post-stall flying with it, the conversion of thrust into noise is annoying



I've made all sorts of little mods from making gap seals with scotch tape to adding balsa yaw vanes to the nose. My next addidtion will be leading edge droop/notches to try to remove wing-rock.

It's a neat little flyer. Funny, Tower sells them overweight and under-powered. If they'd just used a different (not more $$, just different) selection of parts, it wouldn't have the horrible reputation that it does.

I have a thread that's served as sort of a log of my development with this little plane. You might check it out for some inspiration:

http://www.rcuniverse.com/showthread...hreadid=920674]

John, a very interesting thread. It is a fun to tinker with the airplanes but it is nicer when they work right the first time. That is a cute airplane but it has a problem with weight I guess. I have a couple of F-4 foamies that turned out too heavy for the geared speed 400 I had in them. No amount of coaxing would make them fly well. The weight just needs to be 16-18 ounces or less for that power to perform well. Luckily I have a big stack of pink fan fold foam!

Ben