Mods-R-Me

My Feedback: (1)

Thanks. Glad to know I have inspired others to delve into the unknown. Making my kits unique and doing something that hasn't been done before is the best part about modeling. I graduated college with a B.S. in Mechanical Engineering, but once I became an engineer I did very little engineering . My wife makes fun of me all the time by saying that I went to college so I can build better R/C planes [sm=lol.gif].

If you want an idea for you next kit...I plan on building a DC-3 in full WWII paint scheme that can air drop 5-10 paratroopers (GI Joes with parachutes) through the side doors. I hope to have it completed for D-Day. Maybe you could get it going and give me some pointers later.

Mods

parrthd

i dunno......my skybolt probably won't be done by then.....LOL i have been thinking of a drop mechanism for the paratroopers....still have to work out a few kinks.....i'll email you a pic once i draw it off...

Mods-R-Me

My Feedback: (1)

Me too. I was thinking of using a micro processor, servos, and a few motors to shoot them out and away from the aircraft. The microprocessor will automate all the electronics so I can activate the system by flipping one TX switch. The paratroopers will be stored in a "hopper" like device. We can exchange ideas through PMs once the drawings are complete.

Mods-R-Me

My Feedback: (1)

Fuse Sheeting

Got the top of the fuse sheeted and started installing the wing retainer (figures 1 & 2) when I decided it would be better to complete the wing first. I'm modding the wing retainers by having the screw installed from the bottom of the aircraft rather than the top. The instructions want you to drill a hole through the assembly, tap it for the screw, then build the wing and hope it aligns with the hole drilled earlier. Didn't feel good about that until the wing is completed, so I set aside the fuse and began constructing the wing.


Figures 1 & 2


Wing Construction & L.E. Flap Mod 1


Constructed the wing according to the plans up until this point (figure 3).


Figure 3


I added web sheeting around the wing tube (figures 4 & 5) and plan to epoxy the end between the sheeting. Gives me a little more confidence that it will hold .


Figures 4 & 5

Mods-R-Me

My Feedback: (1)

Wing Construction & L.E. Flap Mod Cont. 2


There were no set dimensions for the L.E. Flaps so I had to scale down the actual SU-27 schematics (figure 1). They looked dead on so I transferred them onto the plans.


Figure 1


First, I cut and attached two sub spars, 6A & 6B (figure 2), on the tip end of the L.E. Flap (LEF). I used a straight edge to match them up with the cord line. These will serve as end caps for the LEF and wing leading edge. Next, I used a longer straight edge to mark cut points were the LEF will separate from the wing (figure 3).


Figures 2 & 3


Then, I used a razor saw and straight edge and cut along the lines drawn in the above step (figures 4 & 5).


Figures 4 & 5

Mods-R-Me

My Feedback: (1)

Wing Construction & L.E. Flap Mod Cont. 3


This is where it got tricky. The LEFs run right through the wing retainer. Reducing the glue-able area by 60%. Imagining how it would look if the wings came off during flight [X(] prompted me to find an alternative way to secure them. I figured the best way was to embed the retainers into the wing leading edge and secure it with 30min epoxy mixed with milled fiberglass (figure 1).


Figure 1


I did it by cutting a notch in the leading edge spar and cutting off the excess in front (figures 2 & 3). Worked pretty well.

Anyone recommend further strengthening? If so, how? I'm open to suggestions.


Figures 2 (notch) & 3 (leading edge front view)


Next

Should be able to finish the LEF mod this weekend and maybe even test it out once my high torque servos come in.

More to come,

Mods

propjets4me

Hi , I've just joined up to RCU but have been following this, amoungst other threads for a while... not only is the modification spectacular, but the photos are fantastic... This has all attributes of a professional build.. I'm amazed...

I am desperately waiting for AKM to release the F16 which as you know is in the kits forum

again ..amazing quality of explanation and photographics

with information like this I dont need any building skills...lol

crasharama

Welcome aboard,

Nice to have another Aussie on here amongst the crazies [sm=spinnyeyes.gif]

propjets4me

Hi crasharama, didnt know there even was a forum till a couple of months ago, been in here as a guest for a while, and figured it was time to join in... with threads like this , I might learn something along the way

Steelie

My Feedback: (18)

Mods- If you don't already have one, go pick up an inexpensive laser-line-level and use for laying out, marking, measuring from-to for all things model building. I use mine for this very application. Just set the laser up on a shoe box or whatever to elevate just above what you are working on and cast a straight line accross your work. Works perfectly, especially for irregular surfaces. Last time I used it to determine wing incidence by laying a fuselage on its side (didn't need to lay on side ...lasers work in all positions!) and cast a line on the thrust line from nose to tail. I then measured from-to the line at the leading and trailing edges, wing and stab, for an accurate determination. Easy stuff. Get one that casts a broad line that is used for hanging drop ceilings and such. Cost is around $25.00 or so. You will love it.

propjets4me

Hi Mods-R-Me.. when you built the stab,what type of fiberglass weave is that and weight.. I have only seen the traditional white fiberous material or the cheese cloth type..mind you it's been a very long time since I have needed fiberglass supplies.

Mods-R-Me

My Feedback: (1)

That is a great idea [sm=thumbup.gif]! I'm off to Wal-Mart.


Hi Propjet. Thanks for the kind words. I used Hobbico heavy (5oz) weight fiberglass cloth. Probably could of got away with using medium weight (2oz) but I wanted some extra assurance . With the heavy just be sure to squeegee as much of the epoxy out as possible to reduce unwanted weight.

Here's the link: [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXL493&P=0]CLICK HERE[/link]

Mods-R-Me

My Feedback: (1)

L.E. Flap Mod Cont. 4

Separated the LEF from the main wing. Followed by gluing a 1" x 0.25" hard balsa stick to the rear of the LEF and the wings' leading edge. The clamps are there to make sure the LEF and wing remain flush (figure 1) while the glue cures. I then ran masking tape across the top of the wing ribs as a guide and contoured the 1" x 0.25" hard balsa (in line with ribs) using a Dremel tool (figure 2).


Figures 1 & 2



Next, glued scrap 1 x 0.25 blocks in the four hinge point locations along the wing (figure 3). I plan to use medium sized Great Planes hinge points for the LEF. They can be easily hidden with the wing sheeting by hinging the control surface through the top (figure 4). Also I suck at CA hinging .


Figures 3 & 4


Drilling the holes took some planning because the wing is both tapered and swept. For the hinge points to be effective, they must all be installed at the same angle, so I built a quick drill jig (figures 5 & 6). I will use this jig on the other wing as well. This way, both LEFs will have the same amount of travel.


Figures 5 & 6


Semi finished product (figure 7).


Figure 7

Mods-R-Me

My Feedback: (1)

L.E. Flap Mod Cont. 5

Sanded a 15 degree angle into the LEF by hand using a razor planer. This was not easy and had a lot of imperfections so I filled the voids with 30 min epoxy & micro-balloon filler (30E+MB). Then, I pinned the LEF onto a building board and allowed the glue to cure (figure 1). Now, I have a perfect 15 degree angle on the LEF (figure 2).


Figures 1 & 2



I did some digging and found a thread (Link to thread: [link=http://www.rcuniverse.com/forum/m_3017326/anchors_3017326/mpage_1/key_/anchor/tm.htm#3017326]CLICK HERE[/link]) that described LEF and flaperon positions during certain aircraft maneuvers. I will use these figures as a benchmark and adjust when necessary (figure 3). Once I have the top sheeting in place, I'll sand a 10 degree angle into the wing leading edge to achieve a full 25 degrees of throw. Before it was too late I drew a reference line across the wing and LEF so I can accurately measure the control surface throw (figure 4).


Figures 3 (LEF benchmark) & 4 (reference line)



Hinge points fully installed (figure 5)


Figure 5

Mods-R-Me

My Feedback: (1)

L.E. Flap Mod Cont. 6

I could not get a standard sized servo and control linkage around the wing joiner tube so I ordered two very strong micro servos. Hopefully, they will be here by Friday . These servos have dual ball bearings, metal gears, and 75 oz or torque (link to servo: [link=http://www.rcworldofplanes.net/prodView.asp?idProduct=71]CLICK HERE[/link]). I have another servo about the same size as the GWS so I'm using that one as a place holder. It fits almost perfectly between W2 & W3 (figure 1).


Figure 1



I've been devising ways to balance the CG without adding lead and I figured the best way is to build weight into the aircraft; translation: More Mods! This mod is pretty simple. All I did was fully sheet the wings to give a smoother appearance when the monokote is applied (figure 2). I follow one simple rule when applying sheeting to r/c planes: DO NOT GLUE THE SHEETING ON THE WING BY SECTIONS! You will have bumps and ridges that will never come out, no matter how much you sand. Instead, build the entire sheeting on the building board first then apply it. There is a great article on how to do it on [link=http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/construction/edge_join_balsa_sheet_skins/index.htm]www.airfieldmodels.com[/link]. I've used this technique several times and it always works.


Figures 2 & 3



To glue it, I taped off the new section with masking tape, flipped it over, and used medium CA so it will ooze in around the joint (figure 3). I immediately removed the tape and wiped the joint with de-bonder to remove the run off. Following this, I sanded both sides of the wing sheeting with medium grit sand paper (figure 4). Now, you can see the plank lines but you can't feel them !


Figure 4 (Finished Skin)

Mods-R-Me

My Feedback: (1)

L.E. Flap Mod Cont. 7

I attached the sheeting to the wing using thick CA and held it down using 5 lb weights (figure 1). If you're careful with them you won't ding the sheeting. Next, I cut off the LEF sheeting and installed it using thick CA. The curve was pretty steep so I whetted it down with water to prevent cracking (figure 2).

Figures 1 & 2



The LEF mod is almost complete and I am pleased to find that the hinge installation came out just like I hoped. The "knuckle" of each hinge will be hidden by the sheeting thus preserving the scale appearance [8D] (figure 3).


Figure 3



Figure 4 Semi finished product



Next Time

1. Sheet the other side
2. Bevel the wing leading edge 10 degrees
3. Install servos

More to come,

Mods

bob27s

My Feedback: (19)

Nice work !!

However, I'm not sure I would go beyond what you have now and add those additional 10 deg. 15 deg of LE deflection is pretty beefy.

Probably will not do a whole bunch of good added on considering the airfoil. Its a big camber change on a thick wing as is.

(keep in mind the SU27 and F16 airfoils are optimized for transonic and supersonic regimes - LE devices are required there to help them work and perform at slow speeds - we already fly extremely sub-sonic)

Just my 3.25 cents

Bob

Strykaas

Mods,

Do you think there is a way to turn this kit into a pusher ? That's a shame to waste the nose look of this next masterpiece with the muffler [&o]

Mods-R-Me

My Feedback: (1)

I have been toiling with this idea since I bought the kit. Regrettably, that mod is more work than I'm willing to put in at this point. The tail boom could be converted to an engine mount with a little work. Just to throw some ideas out there....

1. You would have to take all electronics and move them as far forward as possible.
2. Fuel tank would probably go waaaay aft
3. Find some way to open the air inlets and direct air over the engine to cool it ( the plane would look better if you hide the engine). Also, an aluminum spinner would look BAD A@# on the rear!

It can be done. Perhaps someone can take up the challenge and join the thread?

Mods-R-Me

My Feedback: (1)

Thank you sir!

Now that you mention it, I was going to leave it at 15 degrees but I could barely notice the change in the camber. I don't mind the extra work for the additional 10 degrees. I'm trying to get a scale landing config out of all these mods. Do you see any negative effects from adding the 10 degrees of throw on the LEF? Your input is greatly appreciated.

Mods

Troy-RCU

My Feedback: (1)

I concur, the Vector EDF jet uses LE flaps and it appears they use about 15 degrees or so. It's said it helps the plane slow down a bit... more than their first wing design. You can also think of it in terms of wing loading, too. Your plane has a much lower wing loading than a fully loaded F-16. Neat project!

Mods-R-Me

My Feedback: (1)

Oh! that does make sense. Too bad I already sanded the additional 10 degrees in last night [sm=lol.gif]. No foul, I can program the throw with the TX if 25 degrees is too much. From the pics, the throw on my LEFs is about the same. I'll post pics tonight of the finished version.

Thanks for you input.

Razor-RCU

My Feedback: (50)

I am not in any way qualified to comment on any of this only to say "Mods" you are an amazing builder-

Beautiful work.... I take two weeks to build an ARF and it ends up crooked- [X(] I can fly ok I guess though

Keep us posted, this is motivational!

Mods-R-Me

My Feedback: (1)

Thanks. Building is one of the few things I'm proficient in. I'll keep posting plenty of pics...trust me.

Mods-R-Me

My Feedback: (1)

L.E. Flap Mod Cont. 8

Sanded an additional 10 degree bevel in the wing leading edge (LE). I began by drawing a line 3/16" back from the front of the LE (figure 1) and cut/sanded the bevel to that line (figure 2). This was purely a little by little operation but only took an hour or so.


Figures 1 (LE before bevel) & 2 (LE after bevel)



I was surprised to find a slight warp in the wings' trailing edge when I placed it on the jig [X(]. Rather than install the sheeting anyway and hope that it gets the warp out; I pinned the wing to the jig and wet the sheeting, spars, and ribs with water (figure 3). Now, I'll will let the wing sit overnight. Whetting the wing like this should get the warp out. This is probably overkill but I don't like warps on my plane [:@].


Figure 3

More to come,

Mods