|May 26, 2007, 06:51 PM|
E-Flite P-38 Build Thread
Hi all! Yesterday my LHS got a part I'd special ordered in so I stopped in. I was surprised to find that they had 3 E-Flite P-38's on the shelf! As I had one on backorder from Horizon Hobby and had just called them earlier that day I was under the impression that no one had them yet.
I couldn't resist - the price was the same as Horizon's ($129.99) and I like to patronize my LHS (Mark Twain Hobbies in St. Charles) so I picked up the plane and all the stuff I needed to finish the build.
I decided to go with the E-Flite S-75's as they're what's spec'ed for the plane. I usually use Hitec HS-55's for something like this but there was no way to tell whether they'd fit (see the photos of the packing job that E-Flite did) so better safe than sorry...
A few hundred bills later I was on my way home with a trunk load of stuff.
I started the build at about 11:00 PM and quit for the night at about 4:00 AM. There were a few items left to take care of this morning so I began again at around 11:00 AM and finished up at about 5:00 PM. All total about 11 hours of building time though I'm sure many here will finish it in half that. I made a few mistakes along the way which contributed to the time the build took.
Anyway, on to the highlights of the build and a few photos.
|May 26, 2007, 07:09 PM|
Part one: packaging and unboxing
Here's a photo of the box that the P-38 comes in. It's VERY big.
Next photo is everything it takes to put the plane together, minus battery pack and esc's (they were camera shy).
Next photo shows the excellent packing job that E-Flite did on the P-38. One area that they might want to consider improving would be to add some padding under the tails. the bottom of one of my rudders shows signs of being a little compressed in shipping. Some bubblewrap taped to the bottom of the box or a styrofoam tray would better support the booms/rudders.
|May 26, 2007, 07:23 PM|
Part two: Parts inspection and assembly
I laid all of the parts out on the table and took a look at them. Everything appeared to be in good shape except for that little hint of compressed foam on the bottom of one of the rudders. The workmanship is good, the detailing is wonderful and the foam seems to me to be of good quality.
The first few steps in the assembly manual instruct the assembler to remove the cockpit and servo covers. Removing the cockpit reveals a very spacious area to install the receiver, battery and wiring. As you'll see later this space gets used up pretty quickly if your going to build it full house (rudder and steerable nose gear). I test fitted a Hextronix 3S1P 2200mAH Lipo and found it to be a tight fit.
The next step is to install the elevator push rod. The manual shows it being inserted through the servo opening but I found it easier to insert the push rod through the boom intake opening as it's more of a direct path. I then placed the E-Flite S-75 servo into the servo bay and drilled a couple of holes to run the mounting screws through. Getting the screw into the front hole is a chore as it's underneath the edge of the servo opening. I didn't have a tiny magnetic screw driver handy so I ended up using a pea sized blob of the clay E-Flite ships the plane with to hold the screw on the screwdriver long enough to get it threading into the hole. I used the same technique in a couple of other steps during assembly.
Also I should mention the servo extensions. You'll need a 12" extension for each servo you put into the booms. If you're going to do the rudders don't do what I did and run the elevator extension and mount the servo then try to do the same for the rudder - you'll be just as frustrated as I was trying to get the extension through the tiny little hole into the boom... Run both at the same time
|May 26, 2007, 07:43 PM|
Part 3: More assembly - Rudder
As I mentioned I wanted to build a full house plane so as I was working on the elevators I thought it's be prudent to take care of the rudders as well. I carefully sliced away at the hinge line and separated both rudders. This foam ate three new blades during this process.
I mounted the supplied two piece control horns onto the rudders with the supplied screws. The manual shows the head of the screw on the control horn side but this is incorrect. A quick tug test resulted in the control horn coming apart. I realized that the control horn backplate is not threaded but that the control horn side is. Took a few minutes to reverse the screws before gluing both rudders in place with CA.
After mounting the rudders I installed the rudder pushrods and the rudder servos into the servo bays. I wished that I'd run the servo extensions and mounted both the elevator and rudder servos at the same time as it was a royal pain to thread through the VERY tiny opening in the boom with an extension already there. I came very close to deciding to remove the elevator servo but fought with getting the extension in the right spot and finally managed this. Perhaps following E-Flite's suggestion to use string would have worked better but as there was none on hand this was not an option.
I grabbed one of the two brushless ESC's and powered up the servos to center them and adjust the control linkage. The pushrods use threaded clevis for easy adjustment. If you're using E-Flite servos you will need to widen the servo control horn hole to fit the pushrod. Also the rudder pushrods looked to me to be short but once the clevis's were installed I realized that they'd work fine.
|May 26, 2007, 08:01 PM|
Part 4: Stupid E-Flite paint! Oh well, on to Ailerons!
With the elevators and rudders completed the manual says to mount the engines next. I spent about half an hour trying everything I could think of to get the cowls off the front of the engine mounting area... I tried gently prying, gently twisting, gently and not so gently pulling and could not get them to budge.
The manual also says to mount the Receiver pretty early in the assembly process. I skipped that as well as I prefer to mount the receiver after I'm sure all the servos work and that I have enough length in the servo cables to reach where the RX is mounted.
So, the wings came next. I should stop right now and mention a bit about the detailing on this model. This plane is simply stunning. The paint work is very good, there are all sorts of little scale details on this plane that will make people take notice and ALL of the decals are applied. I'm very impressed with this aspect of E-Flite's design.
Anyway, wings... To access the servo mounts you remove a couple of plastic covers which are velcro'ed to the wing and have very thin sticky tape pre-applied to them. You remove the backing from the sticky tape once the servo is in place to keep the plastic part from departing the wing in flight.
Also, you'll need two more 12" servo extension cables. I will mention that the servo extension cables my LHS sold me connected VERY loosely to the S-75's. So loosely that I was concerned about them separating in flight. So, because it well after midnight I decided to try reversing the servo connector in the extension connector... And found the connection to be good an solid. I did this for all of the servos connected to extensions so if you notice down the road in the photos that i have the connectors reversed at the RX, that's why.
E-Flite also suggests using a Y cable for the ailerons. My radio will run two aileron servos (and let me use flaps) so I omitted this Y cable.
The S-75's fit perfectly into the servo wells on the wing. I installed and adjusted the clevis on the short aileron pushrods and tested each servo. As I was preparing to install the servo covers I realized that one of mine didn't have any sticky tape on it. Fortunately I have some carpet tape which is about the same thickness and just as sticky... I removed the sticky tape backing and installed the covers without issue.
|May 26, 2007, 08:11 PM|
Part 4: Trial fitting Wings
I thought it would be a good time to trial fit the wings. They have a carbon fiber tube installed in the wing which slides into a larger diameter carbon fiber rod in the center section. Once in place there are two screws per wing which go down through each boom on the center section and screw into a plastic nut on the bottom of each wing.
I struggled with this for about 45 minutes. The wings do not slide easily into the center section and did not want to align. I finally managed to get the screws into the nuts but am not terribly pleased with how E-Flite designed this. It's far too easy to insert the wing, think you have everything aligned, start the screw only to realize that you're not in the hole. As far as I can tell the hole is foam all the way down to where the plastic nut is at the bottom of the wing. Also it's very hard to see this hole through the top of the boom. If E-Flite had run a bit of plastic tubing that is larger in diameter than the screw through the wing down to the nut and made it a visible color (like red) I think it'd be easier to get the screw into the nut.
The manual states that the wing may need to be inserted and removed several times to aid in the seating process but I have found that it is just as difficult to get the hole lined up now as it was the first time I tried. During assembly I had the wings off and on for various reasons 4-5 times...
The clock read 04:00 and I was well past the point of collapse.
|May 26, 2007, 08:29 PM|
Part 5: Breakfast, a trip to the LHS and engine mounting
Morning came way too soon on little screaming 5 yr old feet... That dang kid...
After a hearty girlfriend cooked breakfast and some scolding for working on the P38 until the sun was up I made the appropriate excuses and high tailed it to the LHS for some advice on getting the cowls off the front of the P-38 booms and a few parts... Honestly I was at the point where I was pretty sure that they'd glued them on and I was going to have to cut them off and request replacements from Horizon...
Several of the employees at my LHS are pretty knowledgeable and fly electrics so I found one of them and mentioned that I thought E-Flite had glued the cowls onto the booms through some sort of manufacturing mistake... He replied that they were probably stuck to the paint and that I should use a playing card under the edges to free them from the paint.
Last night I'd tried just about everything but that. My mind was telling me that I needed something thin and flexible but it was way to exhausted to realizes that thin + flexible = a deck of Bicycle playing cards.
Sure enough, one mangled Joker later I had the cowls off the plane. Yippie! Now I can finish this!
The manual says to use a razor saw to cut the mounting sticks to 1 1/4" in length. I couldn't find the thin blade for my razor saw so used a dremel tool with a cut off wheel instead. The mounting sticks are fairly soft so this was quickly accomplished.
E-Flite Q/C should have looked this plane over a bit more. The mounting stick in the right boom of my plane was pretty badly twisted. I gave it a few good tugs and wiggles to see if I could get it out and reseat it but it was solidly in the boom. Test fitting the motor and cowl revealed that the motor in the right boom lined up with the center of the hole in the cowl so I decided not to worry about it further.
The E-Flite manual suggests CA'ing the motors to the stick. I decided to use a screw to mount them as I like to be able to get things apart as necessary.
I wired up the ESC's, making sure to connect two of the wires on the right ESC so it would spin the opposite way and tested to make sure the motors rotated correctly.
This is another step where you'll need 12" servo extensions. You'll also need wire to extend the battery connector from both ESC's to the center fuselage. The hole they give you to do this with is decently sized. Make sure you tuck everything towards the back as you don't want the motor chewing on wire (lesson learned hard way). I then servo taped both of the Phoenix 25's to the bottom front of each boom, removed the preinstalled sticky tape on both sides of the boom and mounted the cowls.
|May 26, 2007, 08:31 PM|
USA, IL, Chicago
Joined Aug 2006
Motor cowl problem
Did you already mount the motors?
In the manual they show that the plastic cowl can be removed. Well, not in my plane, that i just picked up. I tried, but it looks like they are glued right on. How about yours?
I tried to remove one, but there is no way... looks like I will have to cut the front part of it off. There is a line around it, so I guess along the line. But wanted to ask before doing this....
How did you manage it?-thanks!
Just saw your pictures.... and your description right on the money... let see...
|May 26, 2007, 08:59 PM|
Part 6: Center channel and center fuse wiring.
By now there's quite a bit of wiring in the center channel. So much so that the plastic covers E-flite provides are hard pressed to stay stuck down. There's a set of battery leads and 4 servo extensions going through one and a set of batt leads and three servo extensions through the other. I may be out in the grass looking for them at some point
Also the hole that allows the wiring to come into the center channel is pretty small. It takes a bit of work to get all of the wiring through them.
The missing paint is due to one of the mistakes I made during assembly. I'd sticky taped the covers on last night before going to bed and realized this was a silly thing to do this morning. I used a bit of carpet tape to give the covers some new sticky
The manual says to use 14GA wiring to extend the battery connection from the ESC's. The LHS had Deans wiring so that's what's in my center channels. Soldering all of this together at the other end is a bit of a chore... I ended up sizing the wire in the center fuse and soldering both blacks to a single black and then to a the negative connection on a Deans rather than trying to solder to leads to a connector. The Deans wire is just too thick to do that.
I connected all of the servos to the receiver and checked all of the control surface functions. Everything appeared to be working properly though getting the ailerons and flaps functioning right required swapping channels at the RX. The Berg7 receiver I'm using fits perfectly down in a little recess at the bottom of the front pod. It's almost like E-Flite made this recess for a vertical pin Berg. A Hitec RX would probably fit there as well.
You’ll notice that the props are on. They spin inwards towards the center fuse. The props and spinners have to be drilled out for the E-Flite 450 prop mounts as they're both sized for a geared brushed shaft. Get the prop adapters down tightly to avoid spinning them off - I thought I had but still ended up chasing one across the kitchen. Also, if you want to do throttle testing, don't hold the plane behind the nose... I did and managed to smack myself pretty good
The gear was easy to install. Slide the nose gear through the two pre-installed bearing, attach the steering horn with an allen wrench, mount a servo and the nose gear push rod and your done. I've mixed mine in with rudder control and it works well.
Antenna wiring came next and I found it difficult to route the antenna in such a way where it was not going to pass by the battery. In the end I ran it out one of the three holes in the back of the fuselage, taped it to the underside of the fuse and to the top of the right rudder. Hopefully I won't pick up too many power related glitches.
I decided to mount the drop tanks as I think they look pretty cool and, with 2 x 450 outrunners I should have enough power even with their additional weight. I drizzled a little CA into the hole in the wing and slid them home.
E-Flite included some clay to use as balance. I tested the balancing point using my fingers at the approximate location that the manual shows (3/16th" in front of the panel line) and found the P-38 to nose down just a little bit. I'm happy with being nose heavy at maiden and did not add any clay for ballast.
With all the trouble I've had with the detachable wings I thought I'd see if the P-38 fits in my car... Sure enough, fully assembled, the P-38 will fit into a Volkswagen New Beetle
That pretty much sums up the build. Someone in the other E-Flite P-38 thread asked for a close up of the foam so I'm including that as well. I'm too tired to remember how to use the macro mode of my camera so I hope the foam photos will work...
I don't have AUW or wattmeter numbers at the moment. I will prolly skip wattmeter numbers unless someone really wants them as I'm pretty sure that I'm not going to be pulling +25A through both ESC's in this configuration. I don't have a postage scale here (and weighing this thing isn't going to be easy) but, assuming it survives maiden, I can get the AUW on Tuesday.
Now, turning the floor over to you guys. Lemme know what you think, what questions you have or just your general ramblings. As for me? Sleep sounds good right now. I'll reply tomorrow!
|May 26, 2007, 09:09 PM|
Ooops! See what lack of sleep does? I took a quick crappy digital camera video of the P-38 doing a Taxi Test in my driveway.
Prior to filming a guy walking a couple of dogs watched me run her around for a bit then asked, "Are you going to take off???"
Hmmm... A line of houses 8' to the left... a tree strewn hill 15' to my right and about a 40' corridor at 100' high...
P-38 Taxi Test
|May 26, 2007, 09:28 PM|
Best of luck on the maiden.
|May 26, 2007, 09:40 PM|
No... the Inboard blade runs down. If I'm looking at the nose of the plane the prop on my right runs counter clockwise, the prop on my left runs clockwise.
This is how the diagram in the E-Flite manual shows this working and I do have thrust in the appropriate direction
Checked weather report for the rest of the weekend. Looks like tomorrow is my best bet from a wind stand point if there's a break in the rain.
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