SMALL - Telemetry SMALL - Radio
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Old Jun 11, 2015, 10:12 PM
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TT

Thanks for the comments.

The first powered flight you saw was powered by a 6s 1350 watt changesun fan. It was a test fight to see if it was going to be worth the work. The wing is pretty scale in size, plus not having the wing tank/ fins to help the model fly must have played into the flat spin. The wing airfoil is basically (close) off the original BVM F-16. The 3rd model is sitting on my work bench till I get off my a$$ and finish it. The 3rd model is around 90% done. I'm fabricating the canopy and the forward intakes.

It's do close, but I have to get back into the groove to do it right and not just do it.

Steve
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Old Jun 12, 2015, 01:41 PM
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OK, we can perhaps compare notes later: I've gone ahead and ordered the CJM kit based on seeing it fly so well. I'll post a pic of the airfoil it has when I get it. The idea is that it will ultimately be K60G powered.

I will also do a 64-70mm scratch with as close to scale proportions as possible, and as light as possible, so I can get a sense of how this thing flies, before I commit to the bigger plane. It will have slotted flaps, so I can see how these behave.

Right now, I have an RG14 selected, but I think I will take my own advice and go to a 9% symmetrical... I tried a stubby-winged L39 in the sim with RG14 - it flew fine until I tired flaps - did not like that at all - the symmetrical airfoil developed less lift, but behaved better overall. These were all thicker sections of at least 8%.

I think excessive downward-pitching, especially under flaps, may be a real issue here on a cambered airfoil. Even more so perhaps if one sticks to the scale flap panel. At 60% span and 25% chord, that is a lot of down-moment, and there may be some flapperon-like roll instability as well. Would not be surprised if one has to run some aileron reflex (crow) with scale flap dimensions in addition to wing washout.

Agree 100% with the tip tank observation too. On this model, the tanks and ventral strakes / fins seem to be necessary for acceptable directional stability (yaw), given the polars. I won't be flying without those.

Shoot me a PM when you are ready to go back up - I'd love to join you and Scott. I'm in Claremont, so nearby. I saw the test was at Archibald -Marc
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Old Jun 12, 2015, 03:27 PM
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Hi Mark,
Steve plans to add LE flaps on his also..we did not have any flaps on the test plane..biggest problem that one had is the fan was too low in the fuse giving up thrust...If you put any power in at low airspeed it just pitched nose up and locked in the stall..
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Old Jun 12, 2015, 04:07 PM
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OK good to know Scott, thanks. I'll be putting my motors in the tail, so need to remember the thrust line thru the CG! These 104s are tricky, no doubt about it. That's what makes them fun...

I fly out of Hemet Mod masters field these days - let me know if you guys want to come down there for some testing - fewer crowds than Prado and nice paved runway.
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Old Jun 12, 2015, 04:24 PM
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My friend Doug flys there(was the club pres for a bit)...I just had my Micro 104 out last weekend...fun...We will have to plan a trip
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Old Jun 12, 2015, 06:33 PM
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As in Doug Medore?
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Old Jun 12, 2015, 08:08 PM
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Yep!
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Old Jun 12, 2015, 08:11 PM
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great guy, incredible pilot
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Old Jun 12, 2015, 08:44 PM
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Yep! was my best man at wedding
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Old Jun 12, 2015, 09:06 PM
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Hi Scott!

Scott and I are working ( define working as looking at them a lot lately) on a bunch of composite models.

Since we like the 104, in storage. I have a JD Models F-104. The wing construction of foam/ glass sheeting is the best part of that version. The fuse is a bit off in it's shape.

Still cool enough to own.

Steve
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Old Jun 12, 2015, 09:12 PM
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Get to work Steve! maybe sunday test flight
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Old Jul 15, 2015, 06:43 PM
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The CJM kit arrived. Nice piece overall, but definitely a builder's kit. The tail fin is already molded. Building and setting up the elevator stab will be a real challenge. I already dislike the mounting system (similar to Avonds).

The wings are sheeted foam-core. I will redo as built-up. The wing profile is a 9% symmetrical airfoil, pretty much a NACA 0009 Smoothed.
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