Scale Build-Off – Fred Reese 40" span RV-3

[Joker 53150]

For what it's worth, Hobby King sells a finishing epoxy HERE currently in their US Eastern warehouse. It's about half the price of Z-Poxy although who knows what the quality really is. For the price it's worth a test to compare. They do have a lot of detail on use, such as temperature recommendations and how to get as much excess off as possible - good tips for any version of finishing epoxy.

 

[jhitesma]

I'll probably stick with the zpoxy since I can get it locally for the same price as online (but without having to pay shipping) and I've heard so much good stuff about it.

That epoxy from HK looks like the standard BSI/Bob Smith that I fully expected to find at my LHS (every LHS I went to in Ohio always had it with their own name sticker on it just like HK does) and I've had very good experiences with their epoxies and CA's when I was building high power rockets. In fact the description is word for word from BSI's website: http://www.bsi-inc.com/Pages/hobby/epoxies.html

But while I had overall good experiences with the BSI epoxies...I also had a few bad experiences where it would occasionally never cure for me even though I measured VERY carefully by volume as indicated. And after all the effort I'm putting into this build I can't see going cheap on a finishing product

Walmart is a loss for me. Neither of our local walmarts have anything but Devcon 5 minute which I'm not a fan of at all. Stinky, sets up WAY too fast, and not very strong for an epoxy. We have a new C-A-L Ranch store that just opened last month and is kind of like a TSC only bigger and better...they had Devcon 30 minute which I picked up for doing the tail gear tonight (I ran out of the last of the 5 minute I used for the firewall and the two other packages of 5 minute I had were too old for me to trust.) They even had the individual tubes instead of the syringe which is nice because you get a little more epoxy for a buck less

I recently heard good things about the Devcon plastic cement which works a lot like epoxy but is apparently stronger and easier to work with...but didn't want to risk it on this. The 30 minute should be good enough for this and I'll splurge on the Z-poxy for the fiberglass.


Just cutting out my elevator so I can epoxy in the reinforcing dowel while I have some mixed up for the tail gear. Looking at my wood pile it made me realize why this hobby is so addictive. I'm going to have more wood on hand when I'm done than I did when I started Sure, I'll have less 1/16" and 3/16" balsa...but I'll have a lot more ply and other sizes of balsa than I did before I started (like the sheet of 3/32" ply I had to buy a 6"x 12" piece of even though all I needed was a bit about 1" by 1/4" to go next to the 3/32" wire for the tailgear


Thanks again for all the tips and suggestions guys. I really appreciate the feedback and input which is giving me a lot of confidence going forward on this build!

 

[jhitesma]

Going to be hard to put this aside for a day or two and get that hex built...but the hex has been waiting since before I started this build and I'm really dying to see it go together. But now this is starting to really shape up and I can't wait to see the fuselage come together

The tail gear was a bit of a pain and took a lot of careful sanding and cutting and carving and bending...so for the final glue-up I took my time and took lots of photos. It's just a piece of 3/32" piano wire with a couple of bends sandwiched between two pieces of 1/16" ply with a 3/32" piece of ply as a spacer...but getting it to fit just right was every bit as tricky as it looked like it was going to be. Once everything dry fit correctly I used titebond to attach the spacer to the inner piece of 1/16" ply to keep it in alignment. This is all going to get fairly soaked in epoxy so the titebond was mostly just to hold things in place while I did the real gluing:


I had to carve out a bit of wood from the sides to let the tail wire clear as it exited:


With that done I test fit everything one last time starting with the spacer/inner ply sandwich - you can start to see the channel for the gear wire now:


And with the wire in place. Yeah, I know those 1/4" square strips that the bottom skin is going to glue to could have been done better at the end...I had a heck of a time trying to get things to meet just right back here though and decided to just chop them enough I didn't have to worry about them. Would have been nice to have them meet cleanly - but it would never be visible and wouldn't really add much extra strength so I didn't bother:


Finally the outer piece of 1/16" ply with a little notch to clear the wire. I cut this piece a bit bigger than the plans called for just because it seemed like it would make the gluing a bit easier that way:


Since it all looked good I went ahead and epoxied it. I didn't get any photos but under the brick in this photo is the elevator which got a piece of 3/16" dowel epoxied in to join the two halves. Tomorrow once the epoxy is fully cured I'll cut out the rest of the material in the middle currently holding the two halves together and it will just be the dowel holding it.


Once the 30 minute epoxy had cured for about 2 hours I took the saran wrap off. From the inside it looks pretty good...not a lot of excess glue but plenty to hold that all in there well!


The wire isn't 100% straight...but I can give it a final tweak once this is totally cured. It actually came out better than I expected. The outside bit of 1/16" ply didn't come out quite as nice as I had hoped - I tried to cut it slightly oversized but still wound up slightly undersized somehow. A bit of filler and/or sanding though and under the fiberglass it will never be noticeable:


Deciding that the epoxy was cured enough I could keep working on things I decided to go ahead and start adding the top of the fusealage which is made up out of 3/16" thick 1/2" strips:


The back end finally started to make sense to me...This first set of pieces goes the full length, but the next one ends just past the last bulkhead and the one after that ends just after the next bulkhead - then it all gets a piece of 1/4" balsa across the top.


A lot of this is going to be removed with sanding since these are 1/16" thicker than the rest of the sides so when I sand the final shape I expect to loose quite a bit of this. I'm starting to think the guy on RCGroups really had the right idea building the turtle deck out of pink foam instead, sanding all this down is going to be a big mess and a big block of foam would have been easier to deal with than trying to figure out how these strips are going to terminate. But this will give me some satisfaction when it's done. And even though it's probably horribly overbuilt for electric I'm not too worried about shaving weight on this build (though the back is where I would like to shave some) as one of the reasons I wanted to go balsa was for a bigger heavier model to help deal with the wind I often have to fly in. And I can always go with a bigger motor to shift some weight forward and help make up for the extra weight

Can't wait to get the next 5 strips on here and then sand this thing down!

 

[willsonman]

Excellent work my friend.

 

[jhitesma]

Excellent work my friend.

Thanks! I'm really loving this build. After so many quick one or two day foam builds it's nice to be working on something more involved again. And this is by far the most involved build I've ever attempted. Never build from plans before, never done a 4 channel balsa before, never done a sheeted fuselage before....yet I'm not really feeling like I've bit off more than I can chew even though I am a little intimidated by some of it still

The second layer of the turtledeck was a bit harder than the first as it required more sanding to get it to lay flat. It also makes a pretty intense twist between F7 and F8 which took a bit of work to pull off:


I was't able to use clamps because of the angles. I probably could have made some wedges to enable the use of clamps...but trying to hold everything together while shaping them was a pain. So...pins.


The third and final layer of this will be a bit easier than this second layer. It still has some fitting to do but doesn't have as much of a twist. Once the 3rd layer is in (I didn't get it shaped or glued tonight) this all gets topped off with a piece of 1/4" balsa. Then about 50% or more of all of this gets sanded off to achieve the final shape. Debating whether to do that by hand or break out the palm sander....my right wrist and arm have been acting up lately so while I can't wait to see it all sanded I'm not in a huge hurry to tackle that job right now.


In real life this view really showed off the twist between F7 and F8...but the photo doesn't really show it as well. At F7 these pieces have about 10-12 degree tilt to them but at F8 they're almost vertical. To get them to make the twist I used my alcohol/water mix and spritzed that section down. Then held them in place for about 5 minutes...then sprayed them again and pinned them in place for about 30 minutes. After that they were mostly dry and I was able to glue and pin them without them fighting the pins.


I also got the rest of the tailfeathers cut out. They still need to be sanded down and I still have to decide what kind of hinges I'm going to use. The plans seem to indicate CA hinges which are what I used on my 60" glider and they still seem fine on there, plus I have the slotting tool for them...but I'm really not a huge fan of them. So debating my options.


This is the one part of this design I'm not huge on. The 3/16" dowel is pretty much the only thing joining the two halves of the elevator. I've broken elevators with more substantial connections before so I'll have to be kind of careful I guess


I also realized I didn't leave a gap for the horizontal stab when I added the 1st layer of the turtledeck. So I'll have to go back in and cut that open once everything is sanded down.

Going to be hard not to rush this hex build because I want to get back to this ASAP

 

[Joker 53150]

For the elevator, you could do a dual pushrod setup so each side is controlled which would avoid concern about the dowel.

 

[jhitesma]

Thought about it...but I think I'll stick with the way it's designed unless I run into any issues. I just need to learn to be gentler with some things

 

[jhitesma]

Had a bit of time over lunch...didn't want to deal with the mess of sanding CF for my hex so made a little more progress on this guy even though I "put it away" last night

"last" strip on the left side glued down. But it's a tiny bit short so I'm going to have to add one more little piece to fill the gap at the front top.


Really happy with the fit I got on these, better than I expected and wasn't as hard as I thought it would be. That other top strip still needs to be fine tuned and then glued down.


I may go ahead and sand the tops of this all level and glue down the 1/4" top piece before digging in on the hex tonight...just so close to having this done

Also - the article that came with the plans actually called for sheeting the bottom before even doing this part - but I'm going to hold off on that until right near the end as I'd like the access inside for when I run my control rods so I can add some sleeves for them if necessary. Haven't decided just what I'm going to use yet. The plans call for fairly thin short music wire pieces with longer 1/4" wood pieces in the middle. But I'm leaning more towards using music wire with some sleeves to prevent flex. Once I get the tail feathers mounted and the front finished and everything sanded down I'll figure out where/how I want to mount my servos.

Speaking of which I still need to decide what size servos I want to run. The plane was designed with old school full size servos in mind but that just seems like crazy overkill to me. But I've only used micro servos for my glider, mini servos for my foamies....and full size servos in cars/trucks. Still not sure what size is really appropriate for this...and still haven't decided if I want to use a single aileron servo or two out in the wings (though I'm leaning heavily towards two out in the wings.)

 

[Joker 53150]

Dang it, I may need to get the plans for this plane printed so it can be added to my "to build" list.

 

[jhitesma]

Dang it, I may need to get the plans for this plane printed so it can be added to my "to build" list.

I'd love to see your take on it...if you don't mind them being folded I'd be glad to print out a set on my large format plotter and send them to you. I could look into a mailing tube but I suspect it would cost more than it's worth to send them that way.

 

[Joker 53150]

Oh. Hell. Yes! I'll take you up on that offer in a heartbeat! If it were being built right now the design is clear in my mind, something completely different for this bird.

No rush on the plans, there are already a couple irons in the fire that need to be taken care of. I'll message you my details, and THANKS!

 

[jhitesma]

Well my main focus tonight was on getting this guy ready:



Went smoother/quicker than I expected and was able to do a short test hover in the backyard. Still have a lot of tuning to do and this isn't the controller I'll be running on it for very long, plus it's got another level and some FPV gear to go....but I got it in the air and since it's been waiting since December it felt good to get it flying!


But I did make a bit more progress on the RV:

I went ahead and glued on the top 1/4" layer this morning before work.


I didn't get a shot of it before I dug in on carving it down. I just did some work with my knife removing the large bits that definitely had to come off:


And I sketched in some rough guides for where I want to take it down to. I'd say about 50% or more of the 1/4" and 3/16" pieces are going to be removed before this is done. Hard to believe it's going to be actually round looking at it right now...but there should be enough material to pull it off.


Still debating if I want to do that job with my hand block or if I can get away with using the random orbit for the initial bulk removal. Little worried the RO could remove too much too fast...but there is a lot to take off and my right wrist is really bothering me (I'm a little worried I may have dislocated or broken something in there the way it's been hurting the last week.) I'll probably try the RO with some finer grit paper to keep from removing too much too fast.

But I'll probably also glue up the front before I do that so I can final sand the front and rear to shape at the same time. This kind of sanding always makes me nervous but then almost always goes easier than I anticipated!

 

[Joker 53150]

Depending on how much wood needs to be removed I really like using the Master Airscrew Balsa Planer.



It's fast, accurate, you can adjust the cut/plane depth, and the blade is replaceable. Hobby King and many other sites sell it and the replacement blades.

With that said, you've got a lot of material to remove so the RO wouldn't be a bad idea, just be careful to avoid waves in the wood from sanding too much in some areas, especially between bulkheads where there isn't any support for the wood as it might bow in slightly from the pressure. A longer block sander could help avoid this by spreading the contact area out over a couple formers.

Either way, don't over-think it too much. Take your time and take a little off at a time and you'll get a good result. You can always use balsa filler to fill in any low spots that may happen.

Along with the Master Airscrew Razer Plane, they also make a balsa stripper which is a simple device that holds a #11 blade. You can adjust the width as needed to cut planks from sheet stock. This is normally MUCH cheaper than buying pre-cut planks, and you can also cut them to any width you need. If you don't have one I strongly suggest adding it to your wish-list along with the plane. Both come in very handy for balsa building.

 

[jhitesma]

I do have a nice little Stanley mini plane about the same size...just a little bigger. I was thinking about it as an option...but I'm notoriously bad with planes so I think the sander will be a safer bet. But gotta glue up the front before I decide anyway so I'm not in a huge hurry

 

[jhitesma]

So no progress since last Saturday and the bad news is there won't be any progress for a little bit.

Apparently 25+ years of keyboards and mice have taken their tole on my wrists. I've been exclusively using ergonomic keyboards and mice for almost 20 years after first starting to see signs of the effects on my hands/wrists while in college. But the past few weeks things reached a head. The past month or so I've had horrible pain in my right wrist and have been having a harder and harder time doing my day job. I think using an xacto and razor blades to cut out the ply for the landing gear was the straw the broke the proverbial camels back as that was about when things really got bad for me. I've been wearing a wrist brace since last Sunday to help but I can barely type with it on and it's annoying me more than the pain it's been helping with.

I'm in the middle of the biggest project we've ever tackled at work and while I desperately need to take some time off to rest my hands - it's just not possible as there's no one at work who can do what I do for us. I've got the next 5 days or so off and that's only because I scheduled it before we got the job we're currently wrestling with (and even so despite having my parents in from Ohio I'm having to shave some days off the start and end of my vacation.)

It even reached the point that today I gave in and tried something new. I called our friend the acupuncturist. She's a good friend and I've enjoyed hanging out with her since we met (even found out she was the person evicted from our house before we bought it when her then landlord decided to put it on the market!) But I've always avoided talking "work" with her because I've been a skeptic about acupuncture. But she also has medically a medically trained masseuse who works in her office and I was thinking some deep tissue work may help with the pain I've been experiencing. (My doctor would gladly write me for some pain pills...but even when I broke my leg and had a steel bar installed I quit taking my pills after just a few days because I preferred the pain over what the narcotics did to my head.) Well, she talked me into trying the needles today. And I have to say, even going in as a skeptic and having a history of passing out when things were stuck into me...it worked wonders! She put one pin into my left ankle and like a switch the pain in my wrist went from about an 8 to what I'd call a 3. One more pin and I had to actually move my wrist around to try and find the sore spot. Two more in my wrist and half an hour or so of listing to bird noises and flute music and my wrist was feeling better than it has in months.

So I'm going back again tomorrow and twice next week to try and get on top of this pain. It felt great when I left her office but has now crept back up - and I'm sure typing this isn't helping. But point is I'm taking a week or two off from as much as I can to give my wrist some time to heal. And sanding and knife work are things I can live without so this project has to get set aside until I'm physically ready to return to it.

I'm hoping that will be before the end of the month. If my next three appointments and the 5 days off work do as much good as todays did then I should be able to return to this by the end of the month. If not...it may be a bit longer but at some point I will get this done.

In the meantime since it was my birthday today and my parents are in town my wallet seems to be a bit thicker than normal so I'll be getting the last bits of wood and metal I need ordered along with some finishing epoxy and fiberglass while taking this break so I'm ready to really dive in on the home stretch when I'm ready again!

 

[Joker 53150]

First, happy birthday!

Sorry to hear about the pain, and am surprised to hear about the acupuncture. Having no experience with it it's easy to discount as nonsense. I may need to look at that as an option that would allow me to avoid the knife for my shoulders which are a bit messed up from rock climbing.

Building a plane is fun, until it causes pain. Take the time you can and get better so you can fully enjoy the hobby!

 

[Tench745]

Hey, Happy birthday! Looks like we share that as well an an affinity for planes and balsa. Hope you feel better.

 

[Joker 53150]

Food for thought regarding your eventual fiber-glassing of the fuselage... I was reading about finishing epoxy vs WBPU, and one guy's comment about WBPU is good advice:

"If you go this route I know that some have used water based varnishes. But if you go with a water based finish be sure you seal the wood with a solvent based sealer first. Otherwise the water in the finish can cause the wood to swell and alter the surface of the model. Then the finish dries and locks it in shape. So go with some sort of moisture barrier sealer first or avoid the issue by using finishing resins of some form."

I think you were looking at the epoxy for finishing, and if that's the case, disregard the info above. I didn't feel like scrolling through the last few pages to know which method you're considering.

 

[jhitesma]

Thanks for the birthday wishes guys! Round two of needles in me helped a lot today and I'm hoping a few days away from the keyboard the next few days will help even more.

I am planning on epoxy at this point for the FG. WBPU is tempting...but with the warping issues I've had already I think sticking with epoxy will be safer

 

[jhitesma]

No updates yet...but while I was out of town after my birthday I hit up a great hobby shop in San Diego and got some more bits I needed to keep pushing forward with this - including the correct size aileron material.

Just been giving my wrist a bit more rest. It's been feeling a lot better...but is still sore so I've been hesitant to get back to this project until it's feeling normal again.