1/6 SE5a: Building scale with DTFB

[Foam Addict]

The covering is spot on!

I like doculam, I just need to find a local source.

Great job, it looks excellent.

 

[willsonman]

You can have it ordered from staples I think but I've never tried. These guys are a local place and I always try to give local guy business where I can. I too think the covering looks great. I really look forward to this all coming together.

 

[earthsciteach]

Can you shrink it to tighten it up?

 

[willsonman]

You can to a certain degree but its one of the down falls of it. It does not shrink nearly as much as other coverings. My disadvantage is that I'm not that good with iron-on coverings, unless its solartex. That stuff is the best but its also the heaviest iron-on covering out there.

 

[willsonman]

I finished up another aileron last night. Painted the bottom of the two and will move on to the top later. I also worked on the magnets for the hatch.

So my initial idea for the cowl was to make a single flat piece of foam and hold it on with magnets and locator rods. I will still use this but am modifying the design. I started the assembly by cutting a 1cm wide strip of 1/64 plywood. This is basically the thickness of card stock. I realized the bend would be sufficient to maintain shape better than using cardstock since it is more rigid. This will also provide a lip for the hatch to tuck under. With the thickness of the foam at about 1/8 inch it was very flimsy even with the wood glue in the center. So, once I have the placement done I will then cut out the rectangles for the radiator vanes and do that construction with styrene or ply. Styrene cuts better but ply holds paint better. I'll use some metal mesh behind the radiator vanes to simulate the radiator. Its thin stuff so minimal weight and will not interfere with the motor. I'll also add the top bump of the radiator with a small piece of thin balsa. This all has to be done carefully do that the prop does not strike the details. Its all within a mm or so.

Wing planning is also underway. Before I can cover the bottom wing I have to plan how the bottom of the IP strut mounts will be attached. Also, I need to plan for guy wire attachment points. I also need to do the cap strips for the remaining ribs that need them. Lots of work left on the bottom wing before I can cover.

 

[willsonman]

Ok, I've made great headway on the front end. The battery hatch is secure. the front cowl is coming along and it is working well. I have roughly 2mm clearance between the back edge of the prop and the foremost protruding point of the cowl. Keep in mind that this is all held together by magnets.

Lesson #1: NEVER throw away a dead motor. The magnets can be extracted for use. The bearings can be used as back-ups as well as the shaft. I burned up an ExceedRC motor a while back and it has made this process super easy.

I put the bottom wing on to see how she is looking. Everything looks true and square. I think that the rigging will be required as it will had more rigidity to the wings and actually be functional. Unfortunately this means that the separation of the wings for transport will not really be an option. Oh well. I also want to do a show-and-tell of sorts at my club meeting tonight. I plugged in a battery and revved up the prop a bit. It pulls well and I am sure it will be more than sufficient. Two coats of paint on the ailerons too. Needs more unfortunately. Time to move more to the bottom wing.

 

[Blackbeltrrf]

Your build is quite great! I attached a few Pics of my Parkzone in case you just wanted to see anything it has you might want to duplicate but it seems you have it down pat. I can't wait to see your bird fly. If it is like mine whatever you do do not try to glide it in for landing because it will fall out of the sky like a rock Ask me how I know. Power it down all the way to the ground.

 

[willsonman]

Thanks! I really am not anticipating a rock simulation with this bird. With how light it is and the wing area I suspect I will have a hard time getting her down. My last one, which was basically the same, had ZERO bad tendencies. I think PZ did a fair job with their SE5a but there are MANY scale details that they did not carefully consider. I'm referencing photos of an actual airplane. The differences are subtle but if you are going for scale, do it or don't. Examples based on your photos alone:
Taper on wing tips is too square
tail rigging is incorrect
Wheels too small and gear is too wide of a stance
Foster mount comes all the way down to the scope mount... not free floating
the H-stab was not airfoiled with ribs and sub ribs. It was tubular frame construction with a flat plate airfoil
and the tail wheel

Not bashing your plane at all. I've read nothing but good things about it and I'm sure its a blast to fly. I'm more of a purist when it comes to scale features. In fact after I crashed my first build I contemplated the PZ version because I really wanted another. I decided not to because it would take a lot of time to modify it how I wanted it. Thank you for the pictures!

 

[Blackbeltrrf]

No offense taken. After all I didn't build it I bought it. Yours is great and I am just waiting to see if it flies and want to build one like it.

 

[earthsciteach]

She is looking beautiful! I hope you bring her to FTFF!

 

[willsonman]

Thats the goal teach. I have a fly-in to attend here in MD on the 21st and I hope to have her flight worthy and a maiden by then.

 

[willsonman]

Nothing done as I had a club meeting last night. Reception was good. Some skeptics too This is expected from old-school guys who have no faith in composites... other than their prius. I also took out the AT-6 for a flight AND remembered the video camera. Had a gear failure on take-off so no flight and no carnage. Took the gear apart at the field and I need to just replace the mechanical gear. $30 is no big deal for a set to replace both. The issue is that the grub screws that are supposed to hold the gear legs in place are not keeping the gear leg from twisting. No biggie. Glad it happened then than at FTFF.

 

[willsonman]

Ok, time to raid the Wife's sewing supplies:

For the guy wire tie downs I used bra loops that the hook would go on to... give it a bit of risque character. This was done on the top of the wing and forward of the wing mount location on the fuselage. I prepped the underside of the wing with a piece of balsa and gorilla glue. Used my dremel to cut a slot and more gorilla to hold in place. The fuselage part was perfect as the popsicle sticks for the landing gear provided the perfect hard point for the loops to go into.

I need to make more cap strips for the bottom wing and as promised earlier I'll go over this in detail. I am using 110# weight cardstock. The wood board is prepped with thumbtacks as a scale interval for spacing of the stitching.
Tape the sheet in place.
Run your thread around the thumb tacks.
Press down the thread ends to the board to make it all nice and flat.
Apply wood glue over the threads.
smear with your finger to spread evenly.
Apply wax paper and squeegee out any air bubbles and excess glue if there is some.
Apply weight to keep it flat. Keep in mind that the glue is water-based and can cause the paper to wrinkle as it dries. Thats why you want weight on it... so it dries flat.

I've let this dry overnight. I also applied some tissue and WBPU to the front cowl. I did more work on the battery hatch to have a more scale "pull up" handle to release it. I'll show that detail once done. I applied FG hinges to the top ailerons and will glue them to the wing later.

Next up is to cut and apply the cap strips and make the control rods for the bottom wing. I'm also considering simplifying the IP strut mounts to the same ones I used for the cabane strut mounts. I'll only have to use screws on the top wing then as those have already been completed. No biggie. The guy wire installation will hold it all in place once done.

 

[Foam Addict]

I've always wondered how to do that!

Thanks for the tutorial.

 

[willsonman]

After a weekend hiatus I got back on this last night. No pictures as the majority of work has already been covered. I finished up the cap strips on the bottom wing. I installed the control rods in the bottom wing that go from the bell cranks to the ailerons. I glued in the ailerons on the top wing. I'll move on to the IP strut mounts tonight. If glue time allows I'll shape the leading edge of the bottom wing as well.

 

[willsonman]

Ok, so, Snapped a few pictures of recent progress. First shows the plate and control rod for one of the ailerons on the bottom wing. Second shows the IP strut mounts on the wings. They look to be floating but I did use triangle stock behind them to give more bite into the foam. Third shows bottom ailerons drying. Last shows leading edge shaped. I also knocked out the 4th IP strut. I had made three but ran out of coat hangars. As a tip... after soldering there is usually a bunch of black gook from the flux. I use an old toothbrush and KETCHUP to clean it off. The Ketchup is slightly acidic and it eats away the nasty stuff. It leaves the solder joint nice and clean. The IP struts are simply wire coat hangars and electrical ring terminals. The coat hangar extends about 0.5cm past the solder joint of the ring terminal and the ring terminal is bent 90 degrees perpendicular to the wire. I'm using screws to fasten them down rather than engineer something else.

Once the wing is covered and painted I'll install the IP struts to the bottom first. I'll bend the wire to shape to get the angles right to match up with the top wing mounting points. I'll move onto the strut fairings after that and then the guy wires. The top and bottom ailerons will connect via another strut that will connect to each with popsicle stick ends. I'll use a z-bend on one end and a clevis connector on the other. This way I can adjust the length more precisely.

Really trying to move if I am going to try a maiden by this weekend.

 

[Nathan_116]

So, how much of this would you actually say is made out of DTF, and how much us made out of wood and other materials. I want to start building scale with DTF, but I'm finding 2 difficulties doing it. 1) I can't reside whether to base my build off of balsa plans or design my own. 2) I don't want to stray too much from DTF but I see builds like this and I feel as though its not really possible.

 

[earthsciteach]

Best thing to do is to explore for yourself, man. DTFB can substitute for balsa in many, many areas.

 

[willsonman]

Wing and aileron covered last night. I checked the fit of the struts only to find that I glued them into the wrong location on the bottom wing. No maiden this weekend. I'll have to fix it.

 

[willsonman]

Ok, so I made my corrections and I may still make a maiden. Tomorrow looks like a bust anyways due to wind but Sunday looks to be perfect. I Have some painting that HAS to be done before I put the wing on. Once the wings are on the IPS struts should not take long. The fairings will only take 45 min to lay up and another hour to cover in tissue. Then onto rigging. Hopefully I can get it all done tomorrow and not have to scramble much on Sunday to get out to the field.