GREAT PLANES EXTRA 300S, 60 SIZE, ELECTRIC CONVERSION, 2019 BUILD ALONG

[nhk750]

Flipped the fuse over and got the rear bottom stringers glued in to finish the bottom shape of the fuse, just need to do some final sanding on there now. Next up is the motor box and landing gear.

 

[nhk750]

Im getting the motor mount box assy glued together and realized I placed the firewall in upside down! Good thing you dont epoxy in the firewall until last... Anyway I used Titebond II instead of CA to assemble this and will let it stay clamped until morning. I dont like the way they had you hold everything in place and temp glue with thin CA, so I did it my way. Great Planes has some wierd ways of assembly at times as they love to use CA. THE FIREWALL BEING UPSIDE DOWN IS DRIVING ME CRAZY! But I can wait until morning to flip it.

 

[nhk750]

OK, flipped the firewall and test fitted, looks good but, the die cutting of the parts isn't that precise so some final sanding and fitting will take place when I epoxy the firewall in later tonight. This plane is built using the upside down method (my first plane built this way) and It's easy to get confused if your not paying attention...

 

[nhk750]

I decided to glue in some tristock gussets around the motor box as I felt the design was a little weak in that area, plus this wont add any measurable weight for piece of mind. While the glue was drying on that I worked on the firewall as much as I could before it gets epoxied in. I figured out how and where to mount the ESC, drilled some ventilation and motor wire holes in the firewall and preped the ESC mounting plate (the original fuel tank mounting plate) to be mounted. I'm happy with the ESC mounting as it gives me plenty of battery wire and the motor wires are the perfect length.

 

[nhk750]

All right, got the firewall epoxied in tonight and that will be all the progress for a few days as we have a busy weekend. Hopefully get back to in on Monday...FYI, the fuse is upside down...

 

[nhk750]

Back at it last night, got the ESC connectors and XT90 battery connector soldered on and worked on the landing gear mounting area. My soldering iron tip is coming apart and the ESC wires were just a tad to large of diameter to fit easily into the connectors, so I always struggle with this. I end up heating and smashing the ends of the wires a bit then heat everything, push the connector and wire together and feed solder in. There must be an easier way...

Many people have had issues with the landing gear mounting on this model being weak and breaking during hard landings, so I beefed it up a lot. The plans only have two 3/4" wide rails epoxied in, so I added a 1/4" thick ply plate and a third rail, epoxied it all in and will use three 1/4 nylon bolts to fasten the gear on with. I have seen two nylon bolts break on other planes during a less than hard landing and I think 3 would help prevent this. Yes, added some weight, but I did drill some lightening holes and this is much stronger. I just need to add some bracing internally , sand off the ends, drill and fit the gear and tap the holes.

 

[nhk750]

Continuing to grind away at this project, my work bench is a mess as I do three things at once...getting the landing gear bottom fuse area walled in now.

 

[nhk750]

GOT THE ESC mounting sorted out, it takes a bit of fiddling to get it in there, especially once the battery tray is installed, but I'm confident it will be serviceable once the plane is assembled, if needed. Also getting the gear area nearly complete, just some sanding and drill/tapping left to do.

 

[nhk750]

Got the gear all finished up and she stood on her feet for the first time tonight... I used 1/4-20 nylon bolts and for a little extra strength I used 3 of them on the customized gear mounts.

 

[willsonman]

I'm reviewing you LG mounts and like where you went. Having seen many fixed gear break on this style of airplane, I would also suggest using triangle stock below the mount plates. While you have already epoxied the plates in, smothering more epoxy and some wood should be be too much of an issue if you can scuff up the cured epoxy a bit. Te worry is the plates mash into the fuselage on a hard landing and there is not much "grab" force to maintain the plates from crushing in. I've seen other club members go so far as to sandwich an aluminum plate between two thick pieces of ply as their mounting plate. The aluminum would be drilled and tapped to accept up to 6 bolts to securely hold the gear in place. I'm not saying these are the directions you should take, only what I have observed in my other club members' experiences.

 

[Chuppster]

Yeah, I busted the gear off mine on my maiden (engine quit mid-flight) but thanks to the nylon bolts no damage to the LG mounts.

 

[nhk750]

I thought about adding some tri-stock under the plate, but was worried about more weight and overkill on the design. My glue joint is super clean in there however, so it would be easy to add a piece to it. However, the original design just had you use two small wood screws and no reinforcements, so this is much stronger already. See the pics and you wonder how long this would last on a bumpy grass field!

 

[Merv]

However, the original design just had you use two small wood screws and no reinforcements, so this is much stronger already.

Great build.
No matter how strong you make it, something else is going to break. I choose to use 1/4-20 plastic bolts for my LG. I want the bolt to break, it's an easy fix.

 

[nhk750]

Yes, that's why I went with three plastic bolts, a little more holding power, but hopefully they will break before the fuse does.

 

[Bricks]

Great job so far only complaint is wrecking such a nice plane with electric.

 

[nhk750]

Yes, but it will be one smoking hot electric!

 

[nhk750]

Got the Fiberglass Specialties cowl cut and roughed in. I had to fit it first before I get into the battery access cover build. Now the motor, motor mount, spinner, ESC, and cowl part of the conversion are completed.

 

[nhk750]

While the nice big front cowl opening is nice for cooling, I wonder how it will affect high speed flight? This is a big plane and that opening is pretty big too. I think it looks cool though...

 

[nhk750]

Got some practice with the new scroll saw the wife gave me for Christmas. I think I did pretty good for a first timer...the originals are on the bottom and the ones I made are on the top. I'm loving a scroll saw! Making some formers to brainstorm ideas for the battery hatch.

 

[roversgonemad]

Clean work! I use my scroll saw a lot! It’s a handy tool.

This build is looking good. Very tidy work.