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Old 07-21-2011 | 06:04 AM
  #309  
dumorian
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From: Goshen, VA
Default RE: THE BIG WING BUILD ALONG

Swish!!! Fit like a glove! I was worried about needing to do some shimming, but so far it seems that will not be needed. I'm thrilled! The big worry is over.

You can see it is really tight in the photos. I wanted this motor/weight as close to the nose as possible. More ballast up front will be in very limited space. I have good down thrust, but almost no right thrust. I'll just have to deal with that. Maybe I'll mix some rudder or aileron or both into the throttle? While I was laying it out, the motor would have needed to go way back to get much right thrust. As it is now, I have a couple of 3700 mah 25C lipos that should do a good job just behind the firewall. I'm hoping those and the few bits more... ESC (which I will for sure set up with soft start), a couple or few more servos, receiver... and I hope my balance is really close. I'm hoping for no more needed weight up front. And I surely hope for no needed weight on the tail!

So, the photos. I have the full length of the shaft in the photos. This is because I need the prop adapter before cutting it to length. It will be cut so that the shaft collar can be installed behind the motor which should leave it close to flush with the back of the firewall. The front... I'll work out so that the spinner is close to the nose of the model. I'll grind in some flat spots where set screws go for the prop adapter and the two areas that are flat on the existing shaft.

Removal/installation of this unit is 6 screws. The spinner screw, the two prop adapter screws and the three screws that hold in the firewall. In one photo, you and see the seven screws through the firewall. The one center bottom and the two outermost screws hold the firewall to the block supports. I used 8-32 screws for these. A triangle is the key. Three screws give you a triangle. Four screws give you two triangles. Two triangles really aren't much stronger than one. All the force should be forward (unless I nose in [X(] ), so I should only be dealing with shear force on these screws. I gave the firewall a 'really' good tug and it didn't budge or flew. I think I have 'enough'.

Dave! I keep forgetting you are just up the road from here. Were you at the Harrisonburg IMAA flyin a few weeks ago? Anyway, yes, I'll let you know when it is ready and maybe we can work out your being here. We have a most wonderful runway here. It is 450' x 80' with excellent approaches. Other than Joe Nall, it's the best field I've flown from. Our grass is still a bit rough, but getting better every year. It runs parallel with Little North Mountain, just before it drops off into Goshen Pass. Most days the wind is right and we have an updraft on that mountainside, so reverse slope soaring is easy and one can always get back down to the runway, instead of needing to get back up to the mountaintop. I've also been thinking about a XC with this thing. It might be a pipe dream, but if I go about 10 miles up the road to the top of Greater North Mountain, we could glide back down the valley to our runway. If it is to be done, that would be a good first time at doing this. But, I'm jumping way ahead... first things first... get her finished and in the air.

Maybe being 'short-sheeted' by Towers is a good thing? It moved me onto the motor install. And I've been contemplating a belly wheel. Since it will likely be Monday before my new roll shows up, I suppose now is a good time to go ahead and do that. Now to decide on building a retract or doing a fixed wheel. I don't want to do a retract with 'doors'. I think this would limit the use to only those perfectly manicured airstrips or the grass would snag and damage those doors. It wouldn't hurt to have a bit of an exit air hole for heat and I can't imagine that a quarter of a wheel hanging down would have much drag effect, so I'm leaning towards a fixed wheel, but a retract would be cool. So, now off to the next bit of thinking and deciding.
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