Aerotech 42% - Twin Build

[Fixed Wing]

This will be a thread about building two Aerotech 42% Extra 300’s side-by-side. First, a little back ground. I built one of these kits last year and really liked the way it went together. It flies excellent and in my opinion is only limited by the pilot. On top of that, it’s a good value. As a result, I decided to build an identical plane as a backup. Then I got to thinking that if I’m going to build another plane anyway that it might be just as easy to build two side-by-side. Whether I’m right is still to be determined but so far its proving to be true. Also, I would like to say that John at Aerotech is a super guy to deal with. He does what he says he’ll do, promptly responds, knows what he is talking about and is willing to share his knowledge.

I have watched with keen interest the build threads by Wayne/Walt, Jeremy and others. My hat is off to them for their attention to detail and craftsmanship. I will incorporate some of their methods and lightening techniques into my build, however, certain aspects will be different because of preference. I debated whether to do this thread at all since I probably won’t share any high tech tips or rocket science like Walt & Jeremy do (I say that as a compliment). The only unique thing about this thread is that I’m building two at a time but others have convinced me that there might be some interest in a thread like this. My goal is to build very straight planes to around 38 pounds (all up with cans, etc) while having airframes solid enough to last many seasons. I started these planes last week but just now decided to share their progress. There are many pictures already so I’ll break them up into several posts.

[Fixed Wing]

These pictures are of the boxes the kits came in. All were received in good shape with no damaged parts inside. The pictures show boxes for three kits (2 boxes each), however, one of the kits went to a friend for him to build. The plane on the floor by the boxes is the Aerotech I built last year. The picture of the fuse shows its interior with the canopy and top half of the cowl removed. I’m using it as a reference as I build kits #2 and #3.

[Fixed Wing]

Here are the contents of the two kits. Canopies, wheel pants and some other parts also came in the boxes but aren’t shown in the picture. In case you don’t know, these kits come with things that other competitor kits charge extra for such as two instrument panels, molded fiberglass baffle insert for the cowl, cool looking laser cut turtle deck plate, canister mounting plates, etc.

[Fixed Wing]

These are the motor box sides before and after more lightening holes were cut. 1.9 ounces were saved by these cuts.

[Fixed Wing]

This is a picture of the jig used for building my first Aerotech. I made another set of rails and am using both sets for planes #2 and #3. The rails are 3/4” right angle aluminum purchased at Home depot for about $7 each. They make building a straight fuse almost fool proof.

[Fixed Wing]

These are pictures of the fuselage in the framing process.

[Fixed Wing]

These are the canister mounts. I decided not to use the ones that John provides simply because of preference. These came from Desert Aircraft and will fit either KS or MTW canisters. I use two mounts so the weight of the cans are supported by the mounts without hanging so much on the headers. In the past when I used only one mount the cans got beat up and dented. After switching to two mounts the cans haven’t been abused like before.

[Fixed Wing]

These are pictures of the Gear Plate Doublers before and after some lightening holes were cut. These cuts saved .8 ounces. The Gear Plate Doubler is ¼ inch Ply that is epoxied inside bass rails on all four sides. Not shown in the picture is another 1/4” ply Gear Plate that laminates on top of the Doubler. I replaced this plate with 1/8” ply and saved another 2.9 ounces. This setup could be lightened even more in my opinion but I decided to keep it extra strong since I mostly fly off a grass field with crawdad holes, etc. Screws will be added to the gear plate support rails for extra strength.

[Fixed Wing]

This picture shows the top Gear Plate being laminated over the Gear Plate Doubler. This is 1/8" ply that replaced the original 1/4" ply which saved 2.9 ounces. After looking at it I may lighten it some more? This setup brings the total thickness of the gear mount area to 3/8" with some lightening of the underneath piece. Very strong.

[sweetpea]

I would like to thank you for building me a backup plane!!!

It would go great with my Primary Aerotech

[Redneck Shaun]

Great work. I got an old 40% Aerotech Extra 300 last summer. It's like 7yrs old now. LOL...... These planes last forever!!! It's cool to see what the new 300's look like, as your framing yours up.

[Fixed Wing]

Sam,

These probably won't get the new fancy smancy pilot heads like yours has so you may not want one.