A. J. Clark

Now that's cool.

Pond Skipper

Well done, lovely bird and made good power even on one engine.
Did you test fly the other project?

H5606

Thanks; not yet -

This is the odd thing I've never seen before - fluid-like blister that leads to the hub.




Tornado prop with fluid-filled blister emanating from hub -

Pond Skipper

Unheard of until your photo.
I have seen and used plenty over the years, since the 80's no issues.

H5606

Squeezing the fluid in the blister from the tip toward the hub traces back to a point close to the hub that lines up with the pushrod connecting with the power switch. Even though its only on one blade, I suspect this was the reason for the blister as I had some concern over the vibration of this unsupported length of wire past the front of the firewall and perhaps switch failure.

Pulled out that whole pushrod system and went with a more conventional switch activation by tapping the switch hole for a 2-56 screw and slotting the side of the fuselage. A remove-before-flight clothespin is supposed to keep me from forgetting to switch on -


Switch extension rod contact point -

New means to operate switch -

Remove before flight safety pin -

H5606

Thoughts are that the needle on front engine is probably set too rich resulting in depletion of forward tank first so that airplane is flying solely on rear engine near the end of this video -


Edit: Unknown failure - link doesn't display as a picture or work for me...

Try again - suspect self-induced publishing infraction; disregard edit - link is working now.

combatpigg

My Feedback: (3)

Great looking plane.and what a great looking field...!

H5606

Thanks - great club - what appears to be an asphalt runway is actually "Geomat" woven textile cover.

Field situation and drainage creates a problem over time that erodes channels in the ground beneath the material; perhaps crowning the substrate would help but costly and invasive.

H5606

Finally swapped the Tornado 6x3's with a Cox 5x3 Nylon up front and competition 5x3 re-pitched from 18° to 20° on the rear per reply #133; hard to believe posting nearly 7 years ago -

Counterintuitive as the props now turn same direction but the engines actually turn opposite directions since both props are tractors.

Video of third flight with these props - think I'm a little over-optimistic in vid - seems it performed better with a good setting on rear engine in previous runs so disregard these comments in video.

The idea of increased pitch on rear prop is to get a better bite on the already accelerated air from the front prop with the higher pitch prop at the rear engine...

Sorry, no tach numbers yet but two different Cox Tee Dees check run recently are taching 17K rpm with 25% nitro in recent checks with Cox nylon 5x3; Airrow Two is using reedies.

Note: some observations... airplane now equipped with a lighter LiFe 300 MAh pack + lead and the CG has moved aft slightly - previously a 900 MAh LiFe and formerly with a NiCad. The elevator joiner is now "potted" with Hysol because of some concern that vibration proximity to rear engine was causing some issues with elevator hinge degradation; slave elevator authority has diminished with the tight fit, so may move out one hole on elevator servo arm to increase throw. Concern can be seen/heard in flare at end of flight in the video, transmitter stick was maxed out. Still learning setup hints - allowing rear engine to fire up in reverse so airflow blows over cylinder for needle adjustment, then shutdown and start in normal direction for flight.

Pond Skipper

Great run time and execution of the engine stop landing phase of the flight.
The plane design responded well with the new prop choice, good to see it grooving along.
Cox 5x3 given the engine load in RC application has allowed the engines to run steady.