Estes 747 Air Force One Upgrade and Flight Report

I finally got around to finishing the upgrade on the Air Force. I'll jump right to the end and say it was worth it! I took it out for the maiden flight this morning and had a blast flying it। Even better, it came home in one piece.



The Modifications:

To anyone who has tried to fly the Estes 747 in its stock configuration, god help you. It is basically uncontrollable and I would not recommend it. For the upgrad, I used a Hitec 3 channel receiver, Great Planes 35 amp brushed ESC, and a Thunder Power 3S 2100 Lipo battery.

I started by finding the CG of the plane with the battery and electronics installed. You'll find the CG is roughly on the two large circles under the wing.

Next I disassembled the plane and removed the stock receiver and ESC. All that is required is to clip a few wires and the stock electronics are out. I did not bother removing the power switch.

With the electronics out, I cut the ailerons and elevator. Based of other postings on the internet, I decided not to add a rudder and have been happy with that decision so far. For the ailerons, I initially cut them 1.25 inches deep, 9 inches long, starting 3 inches in from the wingtips. After the first flight, I decided they did not have enough authority. I ended up cutting them an additional 3 inches towards the center making the total dimensions 12in X 1.25in. If I had it to do over again, I would probably cut them deeper, possibly 1.5 or 2 inches. Once the ailerons are cut out, cut approximately a 45 degree angle on the downward side to allow the ailerons to travel in both directions. I cut this angle free hand and would probably have done better to use a guide to make the cut cleaner. With the angle cut, I attached the ailerons to the wing with hinge tape available from your local hobby shop or Tower Hobbies.






For the elevator, I made two cuts straight across at 1.5 inches deep. I gave some thought to making the cut parallel to the trailing edge, but decided not to complicate things so I cut straight across. Repeat the procedure from the ailerons to cut the 45 degree angle and reattach them to the plane with hinge tape. In order to make both sides of the elevator move in unison, you need to join the two sides. I cut a short piece of servo wire and bent it 90 degrees on both ends. I pushed the servo wire thought the end of the tail and glued it in place on both sides of the elevator. So far this worked out well, though I am keeping a close eye on it before and after each fight.







The next task was to install the servos for the ailerons and elevator. The aileron servo installation was straight forward, just cut out about half the depth of the servo and glue in place. I used Dubro servo hardware and ez connectors to rig up the ailerons. I made a small slit in the wing with an exacto knife to hide the servo wire.
For the elevator servo I decided to put in on the top aft of the fuselage and rig the control wire to the top of one side of the elevator. I routed the servo wire through the inside of the fuselage. If you take cut out the rear hatch on the fuselage, you will find it is easy to route the servo wire up to the center wing area.

With three servo leads now terminated at the center wing area, it is time to rig up a wiring harness for the 4 electric ducted fans. I essentially made a pig tail connection, that is soldering all the positive wires together, then soldering them to a short wire with a standard bullet connector at the end. I did the same for the negative wires. Its not the prettiest, but it does the job. For my electronics placement, I put the receiver in the small electronics bay sandwiched in between the two wing halves. I had to enlarge it a bit to accommodate all the servo and motor wires. I put the ESC down below in the old batter slot, and covered it with packing tape for protection. I routed the battery connector side of the ESC through the top of the electronics bay which required cutting a small whole.





The last step was to find a suitable location for the battery. I can't remember the website, but I ended up using someone's idea which was to carve out a cavity in the top of the fuselage, essentially in the top bulge on the 747 (you know, where the 1st class lounge is!). I am using a 2100 lipo which meant I needed to take out quite a bit of foam to accommodate the batteries size. This step is critical as you need to place the battery in the correct location in order to get the CG balance right. I taped the battery to top of the plane, moving it forward or backward until I got the correct location. Once the CG was set, I traced around the battery and commenced melting out foam with my soldering iron. I did this is small stages, frequently checking to see if the whole was deep enough. Once the battery compartment was created, there was still one problem to solve. The forward post used to join the two wing halves is directly under the battery. In order to provide enough clearance, I again used my soldering iron to melt about half of the thumbscrew down. This seemed to work well, and everything fit together nicely. If you look in the picture above you can see where I melted down the thumb screw.



Flight Report:

For the maiden flight I chose not to use the included bungee launch system. Instead, another flier was kind enough to give it a hand launch while I worked the controls. The takeoff went well, only dipping a bit before pulling nicely in a scale like fashion into the sky. The 11.1 lipo obviously helps out, though it is certainly putting more voltage to the motors than in intended 8.4V. This can be mitigated by minimizing use of full throttle while cruising. I found 1/3 to 1/2 throttle allow you to cruise at a nice level altitude. Turns were good, though on the initial flight I found the ailerons lacked much authority, requiring a lot of deflection to bank the plane. I extended them for subsequent flights to a length of 12in which helped quite a bit. For turns all that is required is to bank the plane and use a little elevator to push the tail around. Landings are easy, I found the plane glides well and had a tendency to overshoot my landing area. Flight times with the 2100 lipo where about 10 minutes. I found on subsequent days the plane was difficult to fly in windy conditions and noticed quite a bit if horizontal wobble. All in all, this is a fun plane to fly once the proper modifications are made. The looks are great as is the sound from all 4 engines. Happy Flying!

Easy Star Brushless Upgrade

Its been almost a month now since I upgraded my Easy Star to a brushless motor. It was an excellent decision and I have been flying it almost exclusively since the upgrade. My main reason for upgrading was a desire to turn it into an aerial video/photo platform. At the moment the only camera I have (for plane use that is) is the Oregon Scientific ATC 2000 camera. This is the same one I tried with before with the stock configuration that resulted in a crash. After doing a lot of online research, here is what I ended up with.

Motor: E-flite Six Series 2000Kv Brushless Inrunner
ESC: Great Planes C-35
Prop: APC 6X4
Battery: Lipo 3S 11.1 2100mAh
Futaba 72Mhz TX/RX

I went back and forth on the motor and if I had it to do all over again I might have gone with the 2700Kv version of the motor, but the 2000 works just fine. The full up weight is 27oz. The motor is a drop in replacement as the dimensions are almost the same. The trickiest part of the upgrade was to cut out the old motor and cut the top seam to allow the motor wires to be put back in the original channel. Once that was done, it was just a matter of installing the rest of the electronics and checking the CG.

Maiden Flight: Well lets just say it is well worth checking the rudder servo to be sure things are moving in the right direction. After a few false starts I learned this lesson! With everything hooked up right I found it flew very nice. Take offs were easy and the plane quickly climbed high enough to be a speck in the sky. Through several flights I found the flight time to be 15mins plus with good throttle management. 25-50% power is sufficient to hold level altitude. The motor will not allow for unlimited vertical but according to some of the calculator software it can theoretically do about 40mph on level flight. One of the biggest advantages is the ability to fly in higher wind (10-15mph). The extra power really helps penetrate the wind and keeps you flying.

After a few flights unloaded, I decided to strap on the video camera. I made a quick mount by gluing the helmet mount to a piece of 1/8th inch plywood cut to fit in the cargo bay with the canopy off. I ended up cutting a foam wedge to elevate the camera and point it down the nose of the plane. I secured the camera by putting three rubber bands around the camera and fuselage. The total weight with the camera is 33oz. In order to balance the plane I ended up putting the battery on top of the center of the fuselage (where the wings meet). I secured it with a rubber band and velcro. This setup seemed to work well. I have flow about half a dozen times so far and am very pleased with the performance. With a good hand toss the plane dips a bit but easily gains speed for a good take off. Once at the desired altitude 50% power or so will hold level flight. Landings dead stick are a snap even with the extra weight. If anything it actually makes it easier to land as the plane comes down quicker shortening the area needed for a landing. The trickiest part is learning to fly smooth and level to make good videos. I feel like this has greatly improved my flying ability and been fun as well. When funds allow I plan to by a small digital camera and install an extra servo to start doing aerial photography.

For anyone looking to do a similar upgrade, feel free to email me with questions.

Super Cub Aileron Upgrade

Now that I feel comfortable flying the Super Cub with 3 Channels I decided to give ailerons a try. I won't go into great detail on the build as I followed Dave Smith's blog . The toughest part for me was getting the angle smooth on the bottom side of the aileron to allow it to travel down. Also, I ended up re-cutting the ailerons from 1" to 1.5" deep. I used an old, slightly damaged wing to provide the larger ailerons. I decided to do this as it was clear after the first flight that 1" provided no authority in the air. Also, I went back and forth on whether to reduce the wing's dihedral. In the end I did try to flatten the wing out by putting on book on it over night.

Flying Impressions:

In all honesty it doesn't fly as well as I hoped. I think my ailerons may still be too small and the dihedral too great. I have run into what I believe is "adverse yaw" which means the plane tends to yaw in the opposite direction of the intended turn. To learn more about this well known effect, read this link. This effect can be countered by coordinated the turn by applying rudder input. I find that I can do decent turns by using both rudder and aileron as well as up elevator. I can't make the plane to aileron rolls, likely due to the aileron's fighting the wing's dihedral which was designed to self right as it is a trainer. All in all it is still fun to play around with and should give me some aileron experience for future planes. I may try messing around with the dihedral more at some point to see if that helps.

Here are some pics with the original 1" ailerons.

Hobbyzone Super Cub with an Oregon Scientific ATC2000 Camera

With the increased power of the Lipo battery (3S 11.1V, 2100mAh) I decided to give Oregon Scientific ATC2000 a second try. I used the rubber band helmet mount and some Velcro to secure it to the battery door. If you bend the landing gear in a bit there is just enough clearance between the camera and the ground. The full up weight with the camera is around 32oz. I of course chose a windy day to try this, but what can you do, its always windy! The take off was a little wild but once I got it under control it flew very nicely. It of course flies much heavier which means you need more throttle to maintain altitude and a longer roll out for take off. Landing wasn't too bad, I kept about 1/4 power almost all the way in and killed it just before landing. This was also in part to the strong wind I was landing in.

Here is the video, the actual quality is better but you tube made it a little choppy:

Upgraded Super Cub on a windy day

Today was the first flight of the Super Cub with all the new parts in place. Even though the clouds were ominius and the wind was blowing 10-15 my co-pilot and I decided to press on. For reference my co-pilot is 1.5yrs old but his little fingers are great on the stick ;)


Plane Details:
Stock Motor and Prop
Futaba Pars2 Receiver
Futaba 4 Channel 72Mhz Transmitter (bought TX/RX off Ebay)
Great Planes Electrifly C35 Brushed ESC
2 SG90 9gram Servos (Bought off Ebay from Hong Kong for dirt cheap, $5 each)
Thunder Power 11.1 3C 2100mah Lipo Battery
Deans Connectors
New paint job using foam safe spray paint from my LHS.

The installation of the new eletronics was straight forward with the most coplicated being learning to soldier the Deans connector onto the battery. As the new LiPo battery is larger I decided to put the reciever in the batter compartment and tape the battery in place inside the fusuleage. I may end up switching this around but it will take some modification of the exisint battery box.

The paint job was frustrating and didn't come out quite like I wanted. Though the paint is foam safe I found that it didn't bond very well. Even the gentlist of scratch will chip the paint off. I used the lowest tack masking tape I could find and still it would lift the paint of. I will have to go back and do touch ups on the areas that didn't survive the tape.

Flight Test:

This was the windiest day I have flown to date but let me just say it was fun. The new lipo battery given this plane new life. I don't know how using this battery will effect the motor in the long run as the stock battery is only 8.4V vs. 11.1V. I am trying to mitigate this by not using full throttle very often. I found that 75% throttle was more than enough to rise off ground (ROG) in a short distance. Once airborne into the wind the plane shot straight up and climbed at an incredible (scary) rate. For the first minute or so I though I would completely lose control as the plane gained altitude and bounced around wildly. I looked at my co-pilot sitting comfortably in his stroller and he looked as concerned as I felt. I decided to reduce the power to 50% and I found the plane leveled off and began to stabilize. For the next 15-20 minutes (forgot to record the exact time) I flew a nice pattern slowly on the upwind side and faaassstt on the downwind leg. It was fun playing around with the throttle so the plane basically stood still on the upwind leg. Eventually as with all flights I decided I should stop putting it off and try to land. This was tricky with the wind and I aborted my first attempt. With the old battery I would usually give it full throttle to do a go round, so this time should be no different, right? WRONG! When I applied full throttle into the wind the plane shot up and was almost half way through a loop before I reacted. I figured I had two options, try to complete the loop, or abort....both seemed risk as I was low to the ground and have never done loops at low altitudes. I decided that I would stay with the loop and try to fly out of it. I did this of course knowing that there was a good chance I would hit the ground nose going way too fast. Luckily I made it through and recovered in time to go around and make a reasonably nice landing. I practiced my landings in the wind a few more times and was pleased with the results. A couple of times when I landed harder than I wanted to my co-pilot exclaimed "Uh", leaving out the "O", as he does because he is eccentric (or because he is a toddler). I definitely recommend the LiPo upgrade as it gives the plane much better power and longer flying times. Keep in mind that you have to replace the stock electronics before swiching to a LiPo battery as it is designed for NiMh batteries.

Easy Star with an Oregon Scientific ATC 2000 Camera

I found a deal I couldn't pass up at my local Sharper Image that was closing down. It was an Oregon Scientific (ATC 2000) helmet camera for $60. The normal price is $120 so I was pleased to find a discount. The camera is rugged, waterproof and has an SD card slot. With the included velcro mount the weight of the camera is 6.4 ounces. This is a little heavy for an Easy Star whose weight is 26oz. Never being one to let the pesky laws of physics stop me, I decided to give it try. I decided to mount it in the cockpit sans the cockpit cover. This worked well and kept the CG in place. With nothing left to do but fly I went to the field and gave it a good hand toss. What happened next was quite funny, and unfortunately would have been filmed much better from the ground. The plane climbed about 30 feet or so and almost seemed to stand till, making very little forward progress with the nose pointed up high. The inevitable able happened and the plane stalled, and took a nose dive. In retrospect I should have attempted to land the moment I noticed I wasn't gaining speed. The camera came through unscathed though the nose broke off in the same place as the last crash by my father in law. Luckily it was nothing that a little CA glue couldn't fix. I will have to wait until I upgrade the battery and/or motor before trying this again. Maybe I'll give it a try with the Super Cub? Better buy more glue.....

Hobbyzone Super Cub Lives!

After many months of trial and error, and replacing every part except the motor and gearbox, the Super Cup flies! My lack of experience accounts for the necessity to replace almost every part, but I learned a lot in the process. In the end it turns out the wing was to blame. Though it looked true I now know the dihedral was off (as a result of crashing several times) which cause the plane to pull hard to the right.

I am in the process of doing a custom paint job so I'll hold off on any pictures until that happens. As I mentioned all the parts have been replaced with stock parts with the exception of the electronics and wheels. I currently have a HiTec Mini 6S 72Mhz receiver and a Great Planes Electrifly C-35 ESC. I went with a higher amp ESC that I really need but I want to be able to use it in the Estes Air Force One when I finally get around to modifying it. I decided to take a chance and go cheap..real cheap on the servos, I ordered a Hong Kong special from EBAY for around 5 dollars each including shipping. They are called SG90 and are have similar specs to other 9 gram servos on the market. They are a perfect fit, and other than being noisy, they seem to work fine. I realize there is risk of failure, but the fact that this plane is very cheap, and that I fly at a field that isn't heavily used, makes me worry less about safety concerns. In my quest to find cheap parts I also picked up an Esky brushed 40A ESC on EBAY for 14 dollars (including shipping). Though it is supposed to have a low voltage cut-off, in my tests it ran the battery so low that the receiver started to cutout and send intermittent inputs to the servos. This isn't a risk I am willing to take so I wouldn't reccomend going cheap on this part.

Initial Flying Impressions:

After flying only the Multiplex Easystar for so long this is really a change. I think the Super Cub is a good step up as its flight chararcteristscs are less glider like and more in line with a regular plane. Its also nice to have wheels to make landings and take offs more realistic.

More two follow after the paint job...

Estes 747 Air Force One

Among my Christmas gifts this year was a scale Air Force One (foamie) R/C plane by Estes. It is a very nice looking plane and has four brushed Electric Ducted Fan (EDF) engines. The plane is really marketed as more of a "toy" as it comes with a 27mhz controller and no control surfaces. The plane uses thrust vectoring for control, which means the left/right yaw is controlled by powering down the engines on one side or the other. Elevation is controlled by engine speed. Speaking of engine speed, the stock controller only has two speeds, full and 1/2, which is used in turns.

Maiden Flight - Another oddity was the inclusion of an "EZ Launch system", which is a stake and a long bungee to propel the plane forward. For the maiden flight I decided to go by the book and us the bungee. The initial launch went pretty well...at first I thought I would not gain any altitude but it did start to climb. I managed to make a very large turn to the right very low to the ground when I decided to land as I could tell I wasn't going to be able to control it very well. A second flight ended up about the same but I passed way to close to some walkers in the park. I came in for rough landing and popped two of the engines off. Luckily the engines are designed to pop off in a rough landing. The bottom line on this plane in its stock configuration is you need a very large area to fly and no wind. I tried to fly it again a week later with similar results. I have decided to ground this plane pending some upgrades. The plane is to follow in the foot steps of others on the Internet and add ailerons, elevator, new receiver, ESC and a lipo. According to one of the guys at our local field the plane flies nicely with these modifications.

Super Cub Problems Continue....Easy Star Rocks!!

Before I talk about the Super Cub let me say that the Easy Star rocks! I have had half a dozen or more very successful flights with this plane. The handling properties of this plane are superb and it is very forgiving. I have taken it up quite high with the stock motor, though it does get difficult to tell what attitude of the plane is when it is way up there. Right before Christmas I flew with a couple of guys who are learning on the Easy Star as well. We did a little dog fighting up in the air, chasing each others planes in circles and had some very near misses. Luckily I don't think either one of us was quite good enough to hit each other!

On the Super Cub front....I ordered a new tail and fuselage. I transfered over the stock motor, servos, and Hobby Zone radio system. At this point the only thing which isn't stock is the GWS 10X8 propeller and the Dubro 2-3/4 wheels. Before the maiden flight I trimmed it up, all looked good so I attempted a rise off ground (ROG) take off to give myself a chance to see how it would handle vs. committing to a hand launch. Well, almost a carbon copy of last time. Pull hard to the right. What is going on here? I am just not sure. A couple of things I should have checked (and will when I get time) are the center of gravity (CG) both front to back and left to right. I am really hoping there is a CG issue causing the problem. The other thought I have is possibly the propeller is causing a problem? I read posts from someone who did extensive testing and found the GWS 10X8 to be good. I think I'll throw on a stock prop just to rule that out.

New Toys: Santa was good to me and brought me two new toys. A 2.4ghz wireless camera and an Estes Air force One ducted fan jet. I'll get pictures and stories up when I try them out.