Fly RC

April 15, 2016

P-51 Redtail… Wing repair.

The last big repair task before the P-51 is ready to soar again is to get the starboard side landing gear mounting area rebuilt and get the fixed gear back in place. The downside of course is “no retracts” but on the upside no “heavy” retracts and no need to spend another 100+ on a replacement/repair! Pulling these is going to drop a full half pound and since I’m giving up the pretty gear, I’m going to replace the Robart spoked aluminum wheels with the Dubro light treaded wheels. This will save another 6 ounces or so. Those Robarts are 8 spoke anyway and everyone knows a Mustang has 10 spoke rims… so these weren’t really correct anyway… right?

Anyway to give you an idea what had to be done… check out these photos

Here, I’m fitting some new wood at the top of the inboard rib to give it some meat to mount the gear into! What was there previously is a shredded mess.

You can see that not only is the rail gone on the outboard side but the underlying wood was split and pulled away as well.

After fitting that, I had to do some similar work on the outboard side. This time just scabbing in some additional wood to provide a good base for the rails there. Needed to use some temporary braces to hold it in place while the glue dries.

A bit later with all the rails in place and with careful alignment and drilling… the gear is in place.

2016-03-20 18.00.59-opt

Next I had to piece in the sheeting around those wheel wells. I actually made markings to cut the curved sections by pressing the balsa sheeting down over the edges and letting the fiberglass cut/mark the wood enough to then use my Xacto to finish cutting the outline.

Then just drop it in place and wick in a little CA and we are back in business… well close anyway!

Here you can see some of the railing that needed to be replaced as well as the scabbing for some of the ribs that were a bit… crushed…

Here’s another piece fitting into place…

Here it is with all the parts in place…

Next, had to re-cover and drill new holes to mount the landing gear cover.

After a little covering, the wing looks… well, good enough! I could have spent more time and made this look better but this part of the airplane is only seen as it is flying by at 50′ and 50 miles per hour.

I am just not willing to invest the time at this point in an airplane that is unlikely to see much flight time. I’m more interested in fun, and this bird looks cool but just isn’t my cup of tea.

I’m looking now at putting some new batteries in (and losing a bit more weight in the process). The present pair of 2300mah A123s are 6 years old I believe and really larger than they need to be. If I get some good high quality A123 1100s I would have plenty of capacity to get in half a dozen flights between charges, and still save another 4-6 ounces. With that I should be getting closer to 1-1.5 lbs lighter. I have great hopes this will positively affect the overall flight characteristics.

I’ll try to post an update or two later in the summer when I get a few flights in.

March 29, 2016

BD-5B first flight… and almost last!

Let me just start out stating… when you get to the part of the manual where Aeroworks tells you to balance the BD-5B… and even tells you definitively “Do not skip this step! ” I highly recommend you just move on and leave that ’till after the first flight. This way you will have a much more exciting first flight and it certainly is more likely that you will be able to more easily transport the aircraft back home… I doubt you’ll need a very big garbage bag to carry what’s left. Unless you really want to fly it twice without repairs? I guess that’s one way to go, but if you are a thrill seeker not-balancing is a great way to go! Ask me how I know.

Ok, so maybe you should balance the plane… I opted out of that part so let me tell you a bit about my maiden flight.

It was a nice Sunday morning with the temperature approaching 60 degrees at noon. The wind was a bit brisk for an airplane this small and light (8-12mph) but it was pretty close to being down the runway so not terrible. After loading up and securing a 3S 2200, I dutifully checked all control surfaces which responded appropriately. Thinking back I recalled that I had checked the throws against the recommended and dialing in my usual (fairly aggressive) exponential settings. I even made sure I was in low rates as I expected that at speed this little ship would probably be a bit more sensitive that most that I fly. All looked good so after a quick taxi out on our Geo-textile runway I lined up into the wind and started rolling.

It took a bit longer to rotate and a bit more elevator too (note to self… maybe check to make sure the nose isn’t pointed down slightly??) but then it jumped into the sky and with a little down elevator it… dove for the ground!! Yikes, pull back up and it’s climbing like crazy again… After letting it gain some altitude it became a constant battle to maintain altitude and herd the plane around while constantly trying to find a mix of throttle, elevator and attitude that would smooth out the roller coaster ride. After trying several combinations, and barely recovering from several stalls and one trip to the far reaches of my visual range, I realized it was time to admit that there was nothing that was going to keep this plane flying level and try to figure out a way to get it back down in one piece… or at least a minimum number! Having used every trick that 20 years of RC flying experience has taught me to get to this point… it was time to just line it up, react and hope for the best.

On approach now and trying to outguess the roller coaster ride. Keep in some throttle to avoid any stalls until about 3 feet off the ground and here comes the seemingly inevitable plunge… A last second drop of throttle and simultaneous full up elevator just as it hits the grass with only a little bit of nose first down angle. Holding my breath but it looks like nothing too serious. The structure is apparently intact with only the nose gear pointing back a bit more than when it left the ground. All in all, I wasn’t unhappy with the end result. Just with the mistake that made this such a fight!

Here, you can tell where the wheel contacted the bottom of the body!

And this is back of the nose gear mount… You can see the wood split and allowed the landing gear “bearing” to rotate back

You may also be able to see that there is a groove that looks like there may have been a retainer of some sort but if it was ever there… it’s long gone now. So I created one using a washer and after re-gluing and clamping the wood to restore it to perhaps stronger than original, here is the result.

When I reinstalled it, it seemed as good as new.

Finally, I put the airplane with battery installed up on the stand and not at all surprisingly it took 3 ounces of extra weight were the battery sits… which is far forward… to get it to balance as recommended. No wonder it was such a handful! That equates to about an inch behind the recommended balance point. So the lesson, in case I had any remaining doubts, is “Always double check the balance!“.

To correct this, I can either throw some lead in there or drop in some extra milliamps… Normally, I would go for more battery capacity but I have no use for 2500-3000 3S batteries so I will likely just secure some lead and give it another try. At this point I am lucky to have a plane to fly a second time so I don’t have much to lose. I used all the skill I had and then got just plain lucky to get it down in one piece. Looking forward to a much less frantic flight!

March 23, 2016March 25, 2016

P-51 Redtail… Patching the fuselage… getting closer!

I’ve been rolling right along working on the restoration of the P-51 Redtail to flight status. Today I worked on some minor dings and one big hole that was inflicted during the “off-airport landing” that occurred last year. Yep, I landed a bit short, not crashed!! Never that…

So this method of covering up the boo-boos originated with another war bird that belongs to my flying buddy Kelly. During the construction of his P-40, as I was finishing up one night in the shop, I picked up the wing I had just finished some work on. I believe it was the final item on that wing… probably some servo linkage… that I had just finished and I just needed to sit the perfect wing in the corner so I could clear the bench for another part of the project.

As I swung the wing around the very sharp corner of the bench jumped up in front of the top wingtip surface on one end… maybe 2 or 3 inches in from the tip. It made a really nice divot in the wing and I began to… recite the rosary… that seems right… I know there were some words directed at a deity. That I’m sure of! Anyway, as I unsuccessfully tried to smooth out the damage I thought of the hours of filling/sanding/recovering I’d have to do in order to even come close to restoring this area to it’s original state, I realized that war birds are never this perfect…. Why should this one be? I looked at a few pictures of patched up old birds in real military service and thought I could approximate that look (riveted on bare metal patch). I found a role of aluminum foil/metal duct tape, cut out a square and carefully applied over the ding. Not bad but then I snuck over to my wife’s craft table and found a tool that looked like someone stabbed a BB with an ice pic! Eureka!! A little application of that tool around the edges and my patch job had rivets… or at least close enough for me. After a year or two of flying, that original application is still in place.

So for the Mustang and a few assorted dents and dings…. Here are a couple examples.

This is one to cover the crack that continued from the bottom of the elevator surface back almost to the trailing edge of the fixed portion of the tail. A little glue in the crack and add the “riveted patch”!

This one is right out in the open on the side of the body below the cockpit… Any patch I put here is going to be visible so why not make it look “natural”?

Then comes this monster!

This is just behind the cowl and right where my hand and/or any cradle I might put the plane on tends to rest… plus it is hard to get to the back of this without pulling the fuel tank, which involves pulling the receiver, etc.. I’d normally add at least some sheeting from behind but with that being such a pain… I decided to try a bit of reinforcing before I used the “metallic duct tape” trick. Looking around for some reinforcing I came across some small plastic drinking cups and went to work. The first task was cutting out an appropriate size and shape to cover the damage. The curvature of the cup worked to my advantage on this curved section.

With some more Gorilla glue and a little masking tape, I attached the plastic reinforcement and left it to dry for a few hours. Just in case you don’t find this easily in your local store… here is a link to it on Amazon. Gorilla Glue

Then finally I carefully peeled the masking tape and applied the metal tape.

The tape seems to be the ideal thickness and seems to be quite permanent so I’ll post a link to it here. I’m sure there must be other equivalents out there but this is what I use.

So that’s about it for now. I need to get back to doing a little covering work on the wing and I’ll be getting very close to another “maiden” flight.

March 21, 2016

P-51 Redtail… More progress. Wing repairs progress.

Further work is occurring on my quest to reassemble the Redtail without spending significant dollars and simultaneously lightening it up a bit in the hopes of improved flying traits.

The latest is around the port side (that’s left if you were to sit in the cockpit of the P-51 facing forward) main landing gear mounting area and wheel well. That area took significant damage during the abrupt meeting between the retracts and beans at about 35mph! Yep, that is about stall speed… or at least is was that day.

Here is a sequence of pictures showing the progress. Most of this was simply measuring, cutting, fitting and a fair injection of TLAR engineering methods to try to get something put back together that will stand the strain. TLAR… you know… “That Looks About Right”!

After cutting out the sheeting and getting rid of the various splinters and unidentifiable fragments here is what I was left with.

I cut away even a bit more before adding back a bit of structure… Rebuilding the rails so that the screws have something solid to bite into required some temporary bracing…

Then I started building the actual rail structure and piecing them together with an eye toward making sure there was some interlock to help add some strength. This rail notches into the rib and creates a lip for the rear rail to rest on.

Here, all the rails are in place and all of the mounting screws have been drilled and put in place… lots of advanced TLAR to get the placement right (I hope).

Then came the puzzle of re-sheeting around the fiberglass wheel wells. I cut the existing sheeting back to expose a bit of the top of the spar and then pressed the sheeting down over the fiberglass to give me a cut line. This created shapes like this ones.

Then I added some small “railing” to catch the sheeting and give me some glue surface for the larger span of this piece of sheeting. There was also some reinforcing and rebuilding of the ribs that contact the wheel well that had to be done.

Here are the pieces going into place.

And the final bits of woodwork are glued in.

From here is will just be some recovering work, though I have considered adding a bit of light fiberglass reinforcing underneath the landing gear mount area… We’ll see.

Next up is finishing up the covering and the last of the repair work on the fuselage.

March 21, 2016March 21, 2016

P-51 Redtail… Broken but progress is underway

I’ve been the owner of a 1/5th Scale Top Flite P-51 made up in “Redtail” colors for several years now. If you want to see more on it there are several posts on it, just do a search for redtail or p-51 and you’ll find pictures and information on it.

Last year during a club outing I took her out for a flight or two and managed to stall it just feet from the runway. The straight ahead stall from 4 feet or so caused the landing gear to catch the beans at the approach end of the runway and a fairly violent tail over nose tumble resulted. Another main retract bending extraction from the wing, a punch in the bottom of the body just behind the cowl, along with the horizontal stab breaking loose on one side and cracking across the top of the tail was the result. It was not pretty and it was just a case of not enough airspeed on approach… which I should know well but is easy to forget when you fly so many lighter, easier landing aircraft!

I was truly disgusted and tired of pouring money into this airplane. It has not been a particularly fun or inexpensive airplane to fly and I began to wonder why I continued with it. I can’t say I’ve ever gotten a great amount of enjoyment in flying it… It has pretty much zero of my top 3 most enjoyable attributes when it comes to RC aircraft. It isn’t by any means an impressive flyer as far as it’s aerobatic capabilities, it isn’t easy to get flying or haul around, and it certainly isn’t low cost to fly either. In fairness, I never expected it to be much more than what it is… A complex, heavy, fast, expensive, nice looking and perhaps even impressive war bird!

I talked myself into putting it together and flying it partly just for the varied experience of doing so (check), as a nod to my flying buddy Tim (check), and just to have something that would be both impressive and welcome at war bird and giant scale meets (check). The problem is that I just never really enjoy the way it flies… heavy and fast just aren’t my thing. When I do fly it, I get simultaneously bored with the way it flies and apprehensive since it never flies for long without something needing fixing, adjusted, etc… and often the cost of those repairs just isn’t top of my list so flights are to far apart to ever get totally comfortable with it.

So after the last crash I wasn’t sure I was ever going to get it flying again. It sat over on the side bench for months without my giving it more than a glance and a frown. Several times I had decided to just part it out and or maybe just clean out the expensive bits and do some work to make into a display only airplane with a dummy engine, etc… Finally, I started thinking (maybe it’s just loss of memory and old age) that maybe I could make it fly a bit better and take some of the complexity out of it to make it a bit more reliable?? There are still occasional events I’d like to take it to. Of course that means making it flyable again… without breaking the bank either!

So here is the plan. First, I’ve started working on repairing the damage to the tail and done at least a little cleanup and analysis of the landing gear mounting area. I expect to be able to patch it up with a moderate effort and very little expense. Here are some shots of the repairs in process. Gorilla glue is wonderful thing.

This is the bottom of the horizontal which had separated from the body along the glue line.

This is the point where the wood cracked and broke across the top of the tail… It was one continuous crack/break from that bottom area above all the way across. This allowed the horizontal to “flex” approximately 2″ up at the tip of the horizontal/elevator!!

In addition, one of the main landing gears is toast… Apparently ripping the retract assembly out of the wing, tearing out chunks of wood, shearing the self tapping screws and bending the assembly followed by attempting to pull the retract controller (which is roughly the size of deck of cards) by the wires out of the wing via a quarter size hole… is a bit hard on the electric motor in the retract!! For some reason it doesn’t work anymore!! I guess Robart just doesn’t expect that sort of thing when they build these… go figure. So there will be no more retracts!

So if I get out of the retract business and patch together the wing damage, I can avoid spending about $300 and shave off some ounces. Leaving the controller and both the main retracts behind looks like it will save me about half a pound. While I’m at it, I’m going to pull all of the telemetry. I have enough info from the flights I’ve made that I know pretty much everything I wanted to about how it flies. I may even spend a few dollars to go to two smaller main flight packs (I can reuse the larger packs that are in this airplane elsewhere). If I can manage to trim a full pound out of this bird I wonder just how much better it might fly!?

Here are the completed repairs at the tail with it all buttoned back up.

It seems strong enough. More to come as this is getting done a bit faster than I first supposed.

February 11, 2016

Aeroworks BD-5B – final touches and photos

Did some final work on the BD-5B this evening. Here are a couple photos… still pre-flight.

You can see the Pitot tube (which I love on this plane) along with some of the decals in this shot.

The rear end of this plane has some bite! That spinner (stock) is nice looking and the APC 7x6E looks great and certainly seems to produce some push… at least sitting on the bench.

This view shows the interior which is admittedly cramped and messy with all the goodies stuffed in the right places to make the balance come out as specified. You can see the 2200mah 3S LiPo on the right (tucked into the nose). The tubes coming out from underneath it are going to the pitot which feeds pressure to the airspeed sensor which is tucked in the back (left/upper in the picture) part of the area under the canopy. Hidden under the wires in that same area is the Variometer as well. The Castle speed controller is velcro’d on to the sidewall at the bottom center. At the bottom left of the photo just behind and below the speed controller is the telemetry receiver with the g force sensor attached to it. Just in front of the servos, just peaking out from under the servo tray is the Spektrum receiver.

This may be a bit of over instrumentation for this little bird but once I see the data I can always pull some or all of it out… except the pitot/airspeed as it just looks to good to lose it! Hurry up spring… I need to get a few flights on this bird. 🙂

February 6, 2016February 11, 2016

Aeroworks BD-5B… Assembly

Over the past couple weeks I’ve been working on several projects in the shop as the weather in Indiana has not been especially hospitable for flying. It has been quite a bit warmer than in most years past for the time of year but still not up to my standards for comfortable flying. Sometimes the temperature tempted me but those mild temps usually came with gusty strong winds so no flying lately for me. The good side of that is it gives me some time to work on some projects in the shop!

The latest is the Aeroworks BD-5B I just finished putting together. Mine is pretty close to stock with only a couple small exceptions. On mine there is a pitot tube sticking right out of the front of the nose… which is about the only visible difference. I actually like the look of it on this air frame. Other things that are not exactly per the directions are:

E-Flite DS76 servos instead of the specified Hitec 55s… I like the 55s just fine but as speedy as this thing is likely to be I like having extra precision and torque of a digital.
In addition to the pitot for airspeed, I also have a g force sensor, variometer (altitude and altitude rate of change), temp sensor around the HiMax motor body, and voltage monitor at the pack as well as from the receiver bus.
I chose the Himax 2815-1400 per the written instructions which seems to be rated for quite a bit less power than the E-flite motor now recommended on the Aeroworks web page… I hope it will be sufficient.

I still have to setup the control surface throws and exponential settings but everything else is pretty much buttoned up at this point. Centering and direction of surfaces has been set. I need to apply the decals and any other final cosmetics I want to add and I haven’t picked up the propeller yet, but that is about all that is keeping it from graduating from static model to aircraft at this point.

There were a few minor annoyances when assembling… Belly pan fit could have been better, Canopy could extend down just a bit more or maybe have a structural frame added to help it fit better/keep its shape. Also, I am not a huge fan of the extensive use of the EZ type connectors where only set screws are keeping the control rods from slipping… Much prefer ball joints, standard pin clevises, Z-bends… really most other connection types! I may think about replacing some of those either before the first flight or shortly after if all seems to go well. Just seems a bit “under” designed for a plane that is going to (I presume) move along briskly as I expect this to.

My bird is 29 ounces with a 3 cell 2200mah on board. With the Himax 2815-1400 and an APC 7x5E or similar, I expect about 150 watts which should give me decent performance… 85mph? more? We’ll see soon. I am a little concerned if this will be enough, plus I have never flown a pusher and the lack of airflow over the surfaces at lower speeds (no propwash) has me thinking that landing this might be a bit more interesting. Only one way to know for sure!

I have had this ARF sitting on my shelf for a couple years but until we got a geo-textile runway recently, it just would have been impossible to take off or land without risking damage. Now, with a place to fly, it is finally going to get its chance to soar! Once I dot the last i and cross the last t and get a flight or two I will take some actual pictures and do another post on how it actually flew.. or didn’t!!

January 17, 2016September 7, 2018

Balsa USA 1/4 Scale Cub – Part 4 More Mods – Rudder Shape.

Another modification I recently accomplished on the Cub is to reshape the rudder. Again, I have decided to just look at the general outline of the aircraft. I realize that when covered, some of the “ribs” will not be in the right place and anyone looking closely will be able to tell this but in the air I doubt anyone will be able to tell! They will see the outline, which I hope will at least be suggestive of the real Super Cub!

So here is what I did. After careful comparison of the shape of each I decided that just a bit of a change to the trailing edge of the rudder would take care of the primary difference between the J3 and the Super. Besides… I’m always happy to have a little more control surface! In order to accomplish this I decided I would just laminate a new trailing edge.

Here’s the process. To start I used my balsa stripper to create some strips of the proper width from a sheet of 1/16″ balsa. After a quick sand to make a slight flat spot at my “start” and “stop” areas I pinned down the rudder and used some thin CA to tack down one end of the first strip.

I then bent the stick to shape and tack glued down the other end and then trimmed of the remainder with my Xacto knife.

I then added two more layers of stripping. On each one I used some wood glue between the layers and then tacked it in place with pins and some thin CA to insure it didn’t move before the wood glue set.

Once finished with the third strip, I added some additional support at the point where the existing “ribs” would have contacted the trailing edge. With just a bit of sanding to round things off a bit and to taper the new material at the ends and mate it up with the existing structure, the final shape was complete.

The structure is quite strong and once covered I think most folks will find it to be a fair match to the outline of the real Super Cub.

There is plenty more to do in order to get this bird finished so… more to come!

January 2, 2016January 2, 2016

Freeze Fly fun with the GoPro Session and the Carbon Z Cub

Ever since I picked up my Carbon Z Cub and read the part in the manual about a GoPro camera mount… well I knew that was going to cost me a bunch of money… and I’m not talking about just the cost of the GoPro mount! When I saw that the GoPro Session had dropped to under $200… well there goes my RC budget!!

You can see the mount and camera at the following links if you now suddenly “need” one like I did!
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So over the holidays, with the help of some gift money I got all the goodies and by the time our annual freeze fly came around I was ready. Here is a compilation of my first two flights of 2016. One with the camera perched on the top mount and one with it hanging from the bottom.

By the time I got a chance to go up again the wind was a bit higher and I was less worried about the camera falling off… which it showed no signs of doing in spite of the 25 degree weather and the several loops, rolls, etc…

I used a peel and stick type of mount on the bottom of the airplane (on the plastic belly pan area) and the aforementioned mount from E-Flite for the top mount. I don’t think a tape on type would adhere to this foam well enough and it would certainly come lose if applied to a painted area as the paint on this airplane just isn’t that securely adhered! One of it’s few faults.

Here are a couple pics showing the mounting process for the top mount. in case you are interested in how that was done… First I sliced the foam so that the “fin” on the bottom of the mount could easily insert into the foam at the desired mount location. Placing the mount in place I outlined the area for it with red dry erase marker so that I could easily wipe it away later.

I then used tape to peel some paint off the selected area.

Once finished I wiped away the marker with the aid of some alcohol. Then I mixed up some epoxy and slathered it on the fin and the bottom of the mount generally. I then placed the mount on the prepared area, insuring the fin had glue applied and went snugly into the sliced open slot. Be sure the glue doesn’t get in the slot areas where the camera mount snaps in or this will all be for naught! Wait 30 minutes for the epoxy to dry (actually I wouldn’t trust it until it dried overnight) and there you have it.

I have noticed that the mount is tighter/works better if you insert the GoPro latch assembly from the back. The other direction works but it is looser and I’d be concerned the camera bouncing around and wiggling a bit would affect video quality. The true GoPro stick on mounts don’t seem to have this issue so just be aware.

Hope you enjoy the videos. I’m just getting used to video editing so am hoping to get even better stuff in the future!

December 26, 2015September 7, 2018

Balsa USA 1/4 Scale Cub – Part 3 More Mods – Flaps!!

Another modification I have decided to make on my Cub is to create functional flaps. Below you can see the inboard section of the port side wing.

After extending lines from the trailing edge of the outboard section and then accounting for the thickness of the trailing edge I made some cuts. Here is the result.

I then created a gauge from plywood with the proper angle to match the ailerons and marked and cut the flaps to match. Here you can see it in use.

Once all the ribs were cut to match this angle and length I attached a plate to the back edge in order to finish out the flap structure and allow for hinge attachment.

I then used a plane to match the size and angle I needed on the top and bottom edge of the flap surface.

I will probably need to add some blocks at the hinge attachments point inside the flaps before they are covered in order to insure a strong attachment point. When finished, the flaps look very similar to the ailerons. here you can see the leading edge of the flap (left) and aileron (right)

Aside from the hinge blocks, I will need to work out servo placement in the wing to actuate the flaps before I can call these finished but the major work is done now and overall I am pleased. The only drawback I see is that the angle of the leading edge of the flap surfaces (and the ailerons) are going to limit the throw to approximately 30 degrees of down travel. I feel like that is likely to be enough for my purposes but I’ll do a little research to see what I can determine.

One thought that occurred to me after finishing these up is that I may just plane the corner off of the bottom edge where it contacts the wing surface. I calculated that I could possibly gain another 10 degrees or so of travel this way. I’d be happy with that since the real aircraft maxes out at about 50 degrees… I’ll call that close enough.

While I’m thinking that over, I may finish up reshaping the tail feathers…