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.


-Mark

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).

Great thread Mark!

One thing though. What´s the ground clearance like with the Icepoint gear? Enough to swing a 19" prop?

Keep up the good work with the documentation.

/Erik

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.

Hi Mark,

I have not yet decided what motor I will use. It will probably come down to either the Plettenberg Xtra 25-13 or the Actro 40-5 (much cheaper).

/Erik

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.

Mark,

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!

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

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.

Good night and happy Easter.

-Mark

May I ask what´s the reasoning behind the negative stab incidence? It´s interesting to hear your thoughts on things like this I think.

/Erik

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).


-Mark

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.

I received a question about the spacing beneath the landing gear plate. Here is a pic of the space created below the gear plate by placing some scrap 1/16" below the plate during the gluing process. This is necessary because the bottom of the fusebox will be fully sheeted with 1/16" balsa (cross-grain) and serve as the pipe tunnel floor.....we don't want those ugly blind nuts or screw ends to poke through into the pipe tunnel.

Weather is horrible today, so why not keep building. I cut out the rear formers from 1/8" balsa and then glued them in place with the fusebox fixed over the top view plan. I did some light sanding on the top and bttm to make sure there were no unexpected high spots among the formers. I then sheeted the top rear section of the fuse with 1/16" balsa cross-grain. This will add some strength while handling the fusebox.

I added a small piece of 1/8" sq. balsa on the backside of F-6 to support the 1/16" sheeting at the rear face of F-6. This will allow me to leave a gluing surface for the 1/16" ply that is used on the top from the firewall back to F-6.

Next, will be to setup the elev. pushrods (DEPS) while the bottom rear of the fusebox is still open. I modified my elev. servo position from the plan such that the servo will be on it's side on the fuse floor. This allows for a nice straight (level) shot from the servo arm to the elev. horn location.

Here is a better shot of the shelf left at F-6 for gluing the 1/16" ply on top of the fusebox later (see previous post for text).

Tonight I got the elevator pushrods in place and seemingly friction free. The bottom of the fusebox (full length) can now be sheeted with 1/16" cross grain balsa....maybe tomorrow...after work.

Those deps rods don't flex with the unsupported runs between formers?

At the distances I have between these supports ( <6" ), I have tried and cannot generate enough force with my hands at each end of the rod (putting the rod in compression) to create any flexure between supports. In fact, I was worried that with the amount of force I was applying, that one of the cross member supports would certainly break lose. I think that with the directional strength of the cf, it takes very little support along its strong axis to support it in column bending.

O.K....it's not much but I did get the bottom of the fusebox sheeted tonight.

Looking good!...thanks for sharing the build with us! The lines (and even the build for that matter) remind me of the Boxer series.

FLYINTEXAN, i have to say im impressed with this design. is it a 2 meter design? do you sell plans of the design. also i have a cnc foam cutter we could use to cut wing/stab/fuse if you would like. toby.... www.silhavyaerosports.com

Sean,

Thanks for the kind comments.


Toby,

Yes, it is a 2meter plane and yes, I sell CAD drawn plans that include all foam templates. I posted some details after the test fligths some time ago...see:

http://www.rcuniverse.com/forum/Insi...2540852/tm.htm

I do need to talk with you about foam cores, please send me an email at: [email protected]


Regards,
Mark

p.s. didn't get anything done tonight on the current Insight project, everyday life intervened with a dead car battery after work today.

Nice work flyintexan! It’s great to see that there are a few pattern ship builders among all the 2M pilots on this forum. I bet you are an awesome flyer too!

8178,

You don't know how much wrath you just brought onto me from my flying buddies for that comment. Anyway, thankyou for the kind comments. On that note, I want you to know that I have built two of these planes for not much money. Here is a rough estimate for what I have spent on each plane to get it ready to paint and/or cover:

Wood and CF (lone star balsa) - approx. $85
Landing gear & wheel pants - $50
Wheels - ???LHS
MK tailwheel - $20
DEPS - $20
Wing adjusters - $15
BVM hatch latch - $6
Carbon Wing Tube - $50
Engine Mount (homemade hyde-type)....$100
Plans....(these are mine, but I'm afraid they'll cost you something....) $40

Styrofoam (virgin, 1lb. density) - $25

I used 1/8" dia. CF rod for control horns...cheap
...spend as much as you want to finish with fiberglass and paint and/or monokote...

gotta get to work on the plane now..

-Mark

It was time to cut and fit the top, forward fusebox sheet which is made from a single piece of 1/16" ply. This top piece will tie in all the forward fuse formers and the back of the firewall. As you can see, it starts as a 6" wide x 30" long sheet. I start by fitting the sheet to the back of the firewall which has the right thrust built in. Once I get a good fit there, I cut the other end to length so that it ends where the rear top fusebox sheeting starts. As you can see (barely) in the second pic, all the lightening holes are laid out in pencil. Then I proceed to waste approx. 90% with the scroll saw. I glue on what's left with minimal amounts of epoxy. I also add a 1/8"lite ply firewall brace midway between the top and bottom of the fusebox (glued in with epoxy). With this in place, the 1/8" lite ply firewall is now plenty rigid....in my opinion.