Posts: 951
Joined: 4/8/2003 From: tomball,
TX, USA Status: offline
The Insight (squared) is gaining interest in my local area and abroad. Now that I am framing up a third one for someone here in TX, I thought I might share some of the highlights of the build process.
The plane is mainly built using foam cores that are all sheeted with 1/16" contest grade balsa. The only wood frame building is the main fuse box section...kinda like building a Kaos and attaching foam cores to create the top and bttm. shape of the fuse. Of course, the stab, v. fin, and wings are foam cores as well...heck, even the cheeks are sheeted foam. Simple, strong, and light.
I started as usual by cutting out parts for the fuse. The firewall and main formers (to t.e. of wing) are made of 1/8" lite ply. The fuse doublers are made from 1/16" ply and the fuse sides are med. density 1/8" balsa. The formers from the t.e. of the wing back to the tailpost are made from 1/8" balsa. I trued the the 1/8" fuse sides and 1/16" ply fuse doublers. I then used polyurethane glue to attach the fuse doublers to the fuse sides.....so now I have to wait a while for that to dry.......
Here is a pic of the concept, the fuse side plan (top view cut off), the setup prior to gluing the fuse sides, and some of the parts that I was able get cut today.
Posts: 951
Joined: 4/8/2003 From: tomball,
TX, USA Status: offline
Today I cut the landing gear plate (1/4" ply) and attachted the gear legs (Icepoint gear cut in half). I used four 4-40 screws and blind nuts for each gear leg. The plate will be glued in between F3 and F4 (half former), so now was the best time to setup the landing gear assembly. I also cut lightening holes in the plate to reduce the mass of the plate slightly. I took this opportunity to true up the width of the gear plate to the width of the main fuse formers (1/8" lite ply).
< Message edited by flyintexan -- 3/26/2005 9:04:51 PM >
Posts: 951
Joined: 4/8/2003 From: tomball,
TX, USA Status: offline
Erik,
Actually, YES. Here is a pic of my Insight with a 17x8 apc. The second pic shows a measured distance from ground to prop shaft of approx. 12-1/4" with the tailwheel on the ground. The third pic shows a measured distance of approx. 11" with the stab level (note the mini soccer ball holding the rear of the fuse up). This should allow for a 19" to 20" prop with ease.
-Mark
p.s. I need to get dimensions for the new Plettenburg and I will gladly do a layout in 3D if it will help in your planning and building.
Posts: 951
Joined: 4/8/2003 From: tomball,
TX, USA Status: offline
Went by tonight to see the #2 Insight that is nearing the finishing stage (fiberglassing, etc.).....the owner sanded all the sharp corners off@! I have to admit though, the small radii now sanded into the fuse corners look quite nice. Hopefully, he will post some pics as he progresses on his model. It was nice to see someone with all their hardware ready to go into the new airframe....digital futaba servos all around, YS140sport with a CF pipe, CF landing gear and pants....this thing will put mine to shame when it's done.
Here is a pic of what it looked like next to mine about a week ago when I delivered it to him.
< Message edited by flyintexan -- 3/27/2005 2:48:15 AM >
The Insight looks fantastic. It's really cool to see the amount of work that you have put into this design to get it where it is today. Do you think a ST-2300 would be enough to haul this thing around nicely? I'd kinda like to build one to practice with. It's a simple design, it looks easily accessible, is cheap (and easy) to build, and it looks cool. Thanks alot!
Posts: 951
Joined: 4/8/2003 From: tomball,
TX, USA Status: offline
Ryan,
Thanks, I'm glad you like it. I think the 2300 would have no problem if the finish weight is like mine (9lbs12oz). The framed up #2 in the above post was at 5.5lbs with a YS140 in it (no header, no pipe, just airframe,motor, and mount), so at that point #2 was right on target for 9-1/2 to 9-3/4. However, he does plan to glass and paint the wings...so we'll see.
It's a simple build, just remember these three important words...."sand to fit".
-mark
< Message edited by flyintexan -- 3/27/2005 5:14:11 AM >
Posts: 951
Joined: 4/8/2003 From: tomball,
TX, USA Status: offline
I got a chance to work on the fuse some more tonight: I added the 1/16" vertical grain balsa doubler to the inside of the fuse sides in the stab area. I then made the cutout for the stab using the plans. The stab will be glued in place later at -.5° incidence. Many prefer an adjustable stab, so I included a fore and aft reference hole position on the fuse side view for a stab tube and forward adjuster.
Before moving on, I needed to make a cutout in the fuse sides for the landing gear legs. The approximate cutout position is on the plans. I then carefully squared up and located the fuse sides over the plans and tack glued the main fuse formers in place. I then verified (double, triple, etc. checked) that the fuse sides are parallel and straight and that the front edge of the 1//16" ply fuse doublers begin over the plan as shown. The front edge of the fuse doublers must be even and square to serve as a good reference for setting the firewall and keeping the front end of the fusebox even. I glued the gear plate and support former in place with 1/16" spacers underneath to allow a slight gap between the bottom of the blind nuts and the pipe tunnel floor. The landing gear legs will slide through the fuseside cutouts and be bolted to the top of the gearplate from inside the fuse.
The top view of the fuse shows the firewall at 2.5° of right thrust. The side view shows 1° of downthrust. The downthrust equals about 1/16" of offset toward the back of the fuse when measured at the bottom of the firewall. The right thrust is shown in the top view, so I"ll just glue it over the top view of the plans...tomorrow.
Posts: 951
Joined: 4/8/2003 From: tomball,
TX, USA Status: offline
I use -.25° to -.50° by way of building experience. In the end, the elevators are so big these days (35-45% of the chord) that slight elevator trim adjustments are changing the effective AOA (or incidence) of the stab with very little added drag. I have had experience using a stab tube and adjuster and I prefer the rigidity and very light weight of the glued in stab. I know that many plug in stab setups are very solid, but my experience was otherwise. In flight tests on the first Insight , I ended up adjusting my wing to +1° for straight K.E. flight. Downlines are very straight as well.
I hope this answers your question to some degree (pun intended). I know that there are different, and perhaps more accurate ways to do this setup, but this is simply the method I currently use (I am open enough that I may change my method in the future, if warranted).
Posts: 951
Joined: 4/8/2003 From: tomball,
TX, USA Status: offline
This morning, I predrilled the firewall for the engine mounting bolts and then glued it in place as per the offsets on the plans. After the epoxy was cured, I test fit the gear legs and took a picture (this thing is tall). Next will be to get the fuse set back over the plans, nice and sqaure, and add the rear balsa formers.
< Message edited by flyintexan -- 3/27/2005 6:54:00 PM >
Printable Version
All Forums >> RC Airplanes >> Pattern Flying >> Insight build...another wood roach. 
Insight build...another wood roach. - 
