F-5A Twin EDF40 Nano Parkjet -- Alpha Build Thread

[Lieutenant Loughead]

Hey guys! I was lucky enough to have a conversation with PMPJOHN a few months ago. He told me he was investing in a cool new laser cutter, and was going to begin designing, cutting, and selling "nano parkjets".

I mentioned how I liked the F-5 airframe, and how I would be his first customer if he ever made one... A few short weeks later, he had an Alpha kit ready for Alpha testing! (I would like to make it
clear that this is a Alpha build and any problems encountered will be fixed before production release.)

So, to return the favor, I am going to start a build thread. I've done several build threads on RCG, and I tend to take LOTS of pictures -- so be ready for a lot of downloading! :)

Okay! Here we go! :)

________________________
Want to order one? Here is PMPJOHN's contact information:

John Starks
pmp@strato.net
Office 863-699-5390
Cell 863-633-9736
Website is pending.

Short kits, foam, wood and carbon fiber should end up in the $35-40 range.

[Lieutenant Loughead]

First of all -- PMPJOHN -- please correct me if I misspeak on any subject! :o

It is my understanding that all of PMPJOHN's aircraft will be centered around TWIN GWS EDF-40 power plants. Most of his aircraft are quite small, and do not require brushless motors -- so they are affordable to get into the air.

However, at my insistance, he designed this F-5A for me... It turned out to be a bit larger than the others, and we both wanted to try this one with brushless motors in the GWS EDF-40's...

I will be going with the Feigao 1208428L 12x30mm Brushless Motor. This motor, on a 3s LiPo, should draw around 5.3 amps and provide about 5.9 ounces of thrust with the GWS EDF-40. I'm not sure about the top speed, but it should be pretty darned good. :)

[Lieutenant Loughead]

Okay -- first things first. Open the box, and let's see what we're dealing with.

The first thing I noticed was how CLEAN the laser cut the Depron! I had no idea a laser could cut Depron so nicely, without melting the plastic!

I used an Xacto knife to cut out the parts, and just for fun, I placed the parts together as a sort of "dry fit" exercise.

I've taken some pictures of my progress -- it looks like it's going to be a really fun airplane! (A little history, which may explain my obsession with the F-5 airframe: My uncle was an air crash investigator in the US Air Force, and was shipped all over the world to F-5 crashes. His job was to determine if the engine was running when the F-5 hit the ground. Therefore, I have a "family history" with the F-5 airframe... :D )

Unfortunately, I am still waiting on the brushless motors and EDF units. I don't want to start glueing anything until I know how it will all fit together. Consider this a tease, of sorts, until I can get the project rolling in a few days. :cool:

I will tell you I am going to use a "cold melt hot glue gun" to build this model. I have had excellent results with "cold melt hot glue" on other Depron projects -- just make sure you don't use "hot melt", or you will melt the foam! :eek:

[pmpjohn]

Hey Lieutenant,

A word of caution. Check the amp draw on the fans on three cells. I spooled up a pair of 25 turn Feigao's in the EDF 40's on 3s and found that they were pulling 24 amps:< That is 12 amps per on motors rated for 5.5 amps. I now have 28 turn motors installed and am waiting for 2s 850mah 25c VampowerPro packs to arrive for further testing in the Nano F-15 twin.

John

[Lieutenant Loughead]

Hmmmm -- I've never bought a Fiegao before, so I don't know anything about their number designations. However, the motor I plan to use is a Feigao 1208428L -- I see the number "28" at the end, so I ASSUME it is the 28 turn you are talking about...

Also, I chose the motor based on bench testing at BPHobbies. Their web site says 5.3 amps. (http://www.bphobbies.com/view.asp?id=A0320082) Of course, their web site COULD be incorrect (like, maybe they used a 2s, but listed a 3s)...

Time will tell!

[pmpjohn]

As far as I can tell the last two numbers do = number of turns. Not sure about the "L" long? The motors I have are 12 x 30 mm. I burned a phase out of one of the 25 turn motors. Not real sure if it was the 12 amps or the fact that the one motor failed to start a few times while trying to run them both from one CC P25 ESC. I now have two CC P10's installed along with the 28 turn motors but plan to wait for the 2s packs before doing any further testing. If they are whimpy on 2s I can always go to 3s but once you let the smoke out all testing stops.

John

[Lieutenant Loughead]

Yeah -- "L" must equal "Long". Take a look at this web page (http://www.bphobbies.com/view.asp?id=V219349), and notice the difference between the motors with a "L", and the motors with a "S". :)

[pmpjohn]

Good News

I plugged a 3s pack into the F-15 just to sync the start points of both ESC's and make sure the fans were blowing and not sucking. With my trusty Astro Whatt meter in the circuit I slowly advanced the throttle until it was full on and was pulling 10 amps, 5 per motor. Sooo it looks like the 28 turn motors will take 3s voltage and stay within the rated current draw.

My problem now is the smallest 3s pack I have at the moment is a 1000mah and the F-15 comes out a bit nose heavy. If I am going to maiden the brushless version this weekend I will have to add some dead weight to the tail end.

The F5A is enough longer that the F-15 you should not have any problem with getting her to balance.

John

[Lieutenant Loughead]

That IS good news! Thank you for sharing!

Hmmmm -- I was planning to use a 3s 2220 mAh LiPo... Do you think that will be too much for the F-5A?

[MikeMc]

I can't give you exact detail of the model number but I've been running a 5300 kv Feigao motor in a GWS EDF40 on a 3-cell on the back of a SuperFly delta for a long time with no trouble. However the impeller is not the stock black one that normally comes with the EDF40. It's an orange one that has a couple fewer blades.

[pmpjohn]

The 28 turn motors are rated at 5300kv. I am using the stock 6 bladed impellors for the 5 amp draw.

If the F5A will carry the load of 2200mah she should fly all day and half the night. She only has about 100 sq in of wing area.

John

[MikeMc]

John, make sure you let us know when your website is up with a list of all your kits. This one looks good and I'm interested in seeing what else you have. I don't know about the other people but I like to be different. i.e. No F-16s please. hehe.

[Lieutenant Loughead]

If the F5A will carry the load of 2200mah she should fly all day and half the night.Actually, it would only be 13.32 minutes of WOT flight. You could probably double that time, with really good throttle management...

I have four of these batteries, and only two of the 3s 800 mAh (which would not supply the amps I would need).

She only has about 100 sq in of wing area.Maybe so, however, I like to think that these flat foamy aircraft have much more "wing" area, due to their flat nature... For example, this F-5A has two "decks" just aft of the cockpit -- that makes it a sort of biplane, doesn't it? :D

[pmpjohn]

Lieutenant

If your 800mah packs are at least 15c rated they will do the 10 amps required for WOT operation. Yes the effective wing area should be more than 100 sq in, that is for the wing panels only.

Mike

Here is a picture of the F-15 I have been talking about. Other stuff in the works include a Mig-29 Nano twin, Yak 54 3D ( obligatory ) and two different size LongEZ's. I am open to sugjestions.

John

[MikeMc]

Oh snap!!! F-15 is nice. :<

Here's my short list off the top of my head in order of priority.

A-5B/RA-5C Vigilante (not A-5A)
F-8 Crusader
F-105 Thunderchief
F-100 Super Sabre
Mig-21

[Lieutenant Loughead]

If your 800mah packs are at least 15c rated they will do the 10 amps required for WOT operation.LOL -- I never buy anything more than 10C. In my experience, anything over 10C is just a vendor's con game... :rolleyes:

[pmpjohn]

LOL -- I never buy anything more than 10C. In my experience, anything over 10C is just a vendor's con game... :rolleyes:

Maybe you are using he wrong vendors. I regularly pull 28 amps in my FSK F-16 from 1300mah 3s 25c VampowerPro Platinum packs. That is over a 20c discharge with no problems yet after a couple dozen flights. I like them so much that I stock them. 115gr with Deans mini connectors and velcro. You to can own one for $40.00.:)

John

[Lieutenant Loughead]

Maybe so... However, at 28 amps, you're only going to get a 2.79 minute flight out of a 1300 mAh battery... :o

Hey -- my GWS-40 ducted fans came in today! I must say, I was very surprised to see how SMALL they are! :eek:

Now, I'm waiting on the motors... :rolleyes:

[pmpjohn]

Lieutenant

Actually I get about 5 minutes with throttle managment:cool: That thing is fast enough that more than 10 seconds of WOT even rolling straight up and it is out out my sight:eek:

Where did you order motors from? Aeromicro had mine from CA to FL in four days:) They also have fans and impellors. If you reinstall the original impellors use a drop of thin CA down the hole in the front to keep them on. If you install new replacment impellors they will stay on without glueing.

John

[Bill G]

I've been working on GWS EDF 40 and 50 rotor mods forever. Even the heli tail adapter with grub screws (popular mod) can fail, since the grub screws are so tiny that they don't tighten well.
The best mod I've found yet is to attach servo arm E-Z link metal tang locks to the rotor hub. These are the spring steel locks with tangs in the center, that grip the motor shaft. The idea is to CA glue them to the bottom of the rotor, after drilling a small chamfer to allow the tang locks to recess into. Don't flood the tangs with CA, or they won't lock. They've been working well for me.

Edit: I'm now putting a thin coat of epoxy over the top edge of the e-z clip and down onto the rotor hub to ensure they stay on, as CA tends to be brittle. These have been working great for me.


Bill

[pmpjohn]

That is a great idea Bill, Thanks

[Lieutenant Loughead]

Things are moving along...

Last night, I traced out a copy of the F-5A onto a sheet of Elmer's Foam Board. This is the stuff similar to Depron, with paper on the outside. Let me discourage you from doing this -- the laser cut parts fit together precisely, and my hand-cut parts do not. :o

Anyway, the idea here is to determine the proper CG, without damaging the actual airplane. I will test glide without any electronics. I will post my CG findings soon -- and then my oldest boy will get the airplane as a home-made glider-toy. :)

I discovered I needed to sand the GWS EDF-40 outer case to fit the F-5A airframe. I apologize -- I don't have a picture of how I did this, because I did it at the office, and I didn't want the guys in the shop to realize I was working on a personal project... :rolleyes:

Anyway, I took a block of wood, and used a c-clamp to secure it to the belt sander table. I sanded one side of the outer case, and then placed that side against the block of wood -- this allowed me to sand the four sides exactly square. I took a picture of the final result (see below), but it's difficult to see -- I will try to get a better picture later...

Also, since I will be using brushless motors on this build, I will need two speed controls. I think I am going to try to use a SmartBEC with a Y-cable so that both motors will turn off at Low Voltage Cutoff (instead of just one motor stopping, and the other running). I took a picture of the SmartBEC, and how I set it up to be easily removable. (Before you say anything, the "open air" between the connectors was filled with hot glue, so shorts are not possible.)

[Lieutenant Loughead]

I've been working on GWS EDF 40 and 50 rotor mods forever. Even the heli tail adapter with grub screws (popular mod) can fail, since the grub screws are so tiny that they don't tighten well.
The best mod I've found yet is to attach servo arm E-Z link metal tang locks to the rotor hub. These are the spring steel locks with tangs in the center, that grip the motor shaft. The idea is to CA glue them to the bottom of the rotor, after drilling a small chamfer to allow the tang locks to recess into. Don't flood the tangs with CA, or they won't lock. They've been working well for me.Bill -- how difficult is it to remove the rotor hub after installation, for motor maintenance?

[Geoffrito]

nice F-15, pmpjohn. I've always thought the Su-27 flanker was rather striking...

[Lieutenant Loughead]

Through some trial and error, I believe I've found the proper CG for this aircraft.

11.8 cm from the TRAILING EDGE of the wing, at the wing root.

I base this number on several successful test glides, one of which was approximately 17.5 yards, and ended when the aircraft hit my fence (so it would have gone farther, if it wasn't stopped by the fence)!!!

It is interesting to note -- I had to launch this aircraft VERY hard; otherwise, it just nosed into the dirt. When hand launching this RC airplane, we're all going to have to remember to really chunk it! :)

[Lieutenant Loughead]

Today, I received the motors, speed controls, and heat sinks. Let the build begin. :)

[Lieutenant Loughead]

If you reinstall the original impellors use a drop of thin CA down the hole in the front to keep them on. If you install new replacment impellors they will stay on without glueing.John -- I'm not sure what you mean here.

What's the difference between "original impellors" and "new replacement impellors"? ??

I ordered the fan housing and fan blades from Aircraft World. How can I tell if I need CA on my impellors?

I was going to install the fans and run them up for a peak amp test -- but I will wait until hearing from you first. :o

I am including a better picture of the modification I did to the GWS EDF-40 fan housing. You can see the round intake is now square... :D

[pmpjohn]

Info has changed that would make this original post confusing.


John

[Lieutenant Loughead]

If she wants to balance that far back you will probably need to move the fans back from where they are shown on the drawings. Move the rear edge of the cheater hole back as well. May even need to move the elevator servo Back and mount it in the underside of the rudder piece.JohnWell, looking at it, it does not SEEM like that is very far back... You can look at the picture, and see the location of the clay I added to the nose... It's just about where the battery tray will go, right?

[pmpjohn]

When I bought my fans they came assembled with motors and impellors pressed on. If you bought fans without motors then the hole in the impellor has not been streched out by being pushed on and pulled off and pushed back on again so you should be OK.

When you said 11.8mm from the trailing edge, did you maybe mean 11.8cm? That looks a lot closer to where I would expect the CG to be.

John

[Bill G]

Bill -- how difficult is it to remove the rotor hub after installation, for motor maintenance?Its really not too bad. The problem with the rotors, is that the high power brushless motors get too hot, and the shaft causes the rotor plastic to get soft, which is why they pop off. The small metal-to-metal contact area of the tang locks solves the problem, since the metal locking tang dosen't melt.:D These rotors really don't need much help to stay on. They stay on fine with the brushed motors, but with the brushless, they just don't quite have enough grip, after they get hot. A little extra retention gripping does the job.

Bill

[Lieutenant Loughead]

When I bought my fans they came assembled with motors and impellors pressed on. If you bought fans without motors then the hole in the impellor has not been streched out by being pushed on and pulled off and pushed back on again so you should be OK.Yes, my fans were without motors -- just fan housings and impellors, loose in a box... I will use a drop of CA, after pressing the impellor onto the motor shaft.

When you said 11.8mm from the trailing edge, did you maybe mean 11.8cm? That looks a lot closer to where I would expect the CG to be.Oops! Yes, I intended to say 11.8 cm from the trailing edge... Sorry about that! I will edit my previous post so I don't confuse anyone! :o

Its really not too bad. The problem with the rotors, is that the high power brushless motors get too hot, and the shaft causes the rotor plastic to get soft, which is why they pop off.Hmmm -- well, I'm installing heat sinks on the motors... With the airflow over the heatsinks, I would hope the motor shafts don't get too hot! :eek:

[Lieutenant Loughead]

I've been working on GWS EDF 40 and 50 rotor mods forever. Even the heli tail adapter with grub screws (popular mod) can fail, since the grub screws are so tiny that they don't tighten well.
The best mod I've found yet is to attach servo arm E-Z link metal tang locks to the rotor hub. These are the spring steel locks with tangs in the center, that grip the motor shaft. The idea is to CA glue them to the bottom of the rotor, after drilling a small chamfer to allow the tang locks to recess into. Don't flood the tangs with CA, or they won't lock. They've been working well for me.

BillBill -- I just returned from my local hobby shop. I could not find the EZ Link part you described (and showed in your pictures). Can you please provide me with a part number?

Thank you!

[MikeMc]

I've been flying mine brushless for a couple years now and the rotor has never come off. I have a heatsink on it.

[pmpjohn]

Oops! Yes, I intended to say 11.8 cm from the trailing edge... Sorry about that! I will edit my previous post so I don't confuse anyone! :o


Glad to hear that. Four & 5/8" will confuse fewer Americans:) We are converting to the metric system, one inch at a time::o

John

[Lieutenant Loughead]

I like the metric system, simply because it's base-ten, and has a much finer resolution. :cool:

Hey John -- I did a test fit of the modified EDF units in the COPIED F-5... I was surprised to find the modified EDF units are smaller than the opening. Do I need to fill the gaps, or does it really matter?

[pmpjohn]

As an old Cad & CNC guy I also use a base ten system. Tenths, hundredths and thousandths of an inch.

What is the thickness of the poster board you used for the mockup and how accurate was your knife work? I wouldn't be to worried about the fit until you are installing them in the real deal.

John

[Lieutenant Loughead]

What is the thickness of the poster board you used for the mockup and how accurate was your knife work? I wouldn't be to worried about the fit until you are installing them in the real deal.Agreed -- that's why I made sure to point out that it was my hyper-accurate copy. :D

[Lieutenant Loughead]

Whoops -- I made a mistake... :o

I pushed the rotor onto the motor shaft too far, and it was binding. When I tried to take it apart, it was MUCH more difficult than I imagined!

Eventually, I pulled the EDF unit apart -- one of my two EDF-40's is now destroyed... :o I have ordered two more (one extra, just in case I need it), and it should be here next week.

In the meantime, I ran my usual power test on the one good motor. I used a Tanic 3s 2220 mAh LiPo, and got the following results:

6.07 amps, peak
11.23 volts, minimum
69.5 watts, peak
44600 RPM (this may not be a good reading -- the numbers were jumping all over the place!)
87 grams (3.07 ounces) of static thrust.

[Bill G]

Bill -- I just returned from my local hobby shop. I could not find the EZ Link part you described (and showed in your pictures). Can you please provide me with a part number?

Thank you!
Actually these are just the metal retainers that come with a number of different Dubro, Sullivan, and other standard EZ links. They all seem to be a standard pin size, which just happens to work well for locking on IPS motor shafts. Mine have come from a bunch of different EZ links, since I usually use the plastic press on retainers, thus I have a bag of the metal ones stashed. I'll send you a few if you don't have any and really want to try this out.

I've busted a bunch of those little fan housings, and repaired all of them. The trick is to scuff the plastic with a knife/sandaper, before CA gluing. Without that, the smooth, oily plastic won't glue worth crap. I've also added little pieces of fiberglass with CA into the corners of the vane joints, for reinforcement. I think some of mine are actually stronger than new now.

With the lightweight sheet Depron designs you guys are doing, I would think you could have good success with the 12V low cost GWS brushed setups. I built a very light foam airliner with those motors, and it actually flew well on a small 3s. Definitely have to build to spec though. I designed and built to a wing loading of 8.6oz/sq-ft, which I got from a brushed EDF50 pioneer, Dave Ramsey. Built light, which is tough for me to do since I like tough CF reinforced planes, it worked well. I build to fly and crash.:D Yes, you actually can combine the two qualities well, contrary to some popular opinion.

Bill

[Bill G]

Just to show how well these clips hold on the EDF 40/50 rotors, I had to pull off a rotor today. The rotor really had to be yanked off, and was on there quite well. After removing it, I noticed that the retainer clip was still on the motor shaft (see pic). The CA bond broke from the hard yanking, but this would not happen in flight, where the thrust force is much less than the force of me yanking hard on a rotor, to pull it off.:D

These clips work well. I'm through using the GWS heli tail adapter mod. I had one of those come off. They're a good idea in principle, but they're much more timetaking to install, and the teeny-weeny:Q Allen grub screws will stip out at the Allen wrench, before you can get them tight enough to really lock on the shaft. If they would install the same size (larger) Allen head grub screws that the larger fan rotors use, then you actually could lock them down sufficiently.

[pmpjohn]

Bill

I suspected that You would not get the pushnuts off without cutting them. I have found that turning a small machine screw into the hole in the front of the impellor will act as a gear puller once it contacts the end of the motor shaft and push the impellor straight off the shaft.

A bit off topic, but here are a couple of pics of the Mig-29 prototype. This one will take either EDF40's or 50's. I am waiting on the arrival of a pair of 50's and Medusa 5300kv Afterburners to begin flight testing.

John

[Lieutenant Loughead]

Wow! You are really cranking out the awesome airplanes! :eek:

My EDF-40 are STILL not here... I thought they would be here (for sure) earlier in the week... :(

[MikeMc]

Wow! Looks great. In a production version of your kits is the foam printed & cut, or just cut.

[Bill G]

Bill

I suspected that You would not get the pushnuts off without cutting them. I have found that turning a small machine screw into the hole in the front of the impellor will act as a gear puller once it contacts the end of the motor shaft and push the impellor straight off the shaft.

A bit off topic, but here are a couple of pics of the Mig-29 prototype. This one will take either EDF40's or 50's. I am waiting on the arrival of a pair of 50's and Medusa 5300kv Afterburners to begin flight testing.

John
Usually the pushnuts come right off with the rotors. They really don't need to grip that tight, since the problem is not really grip, but that the plastic rotor hub melts. Those Feigao shafts get hot!
The pushnut came off easily, with tweezers. Actually I did use a screw to remove that rotor, but you could tell that the screw was being worked. The plastic rotors are really on there well, when they're not hot. The problem is the motor heat during operation. The pushnut works, since spring steel doesn't get soft and melt, at a few hundred degrees.:eek:

You'll probably like the Medusa's. I don't have any, but hear they are higher quality. I just changed a motor in my Arado 234 EDF50, since it had a serious turn problem in flight, with a weak motor. The Feigaos are a neat little novelty at a reasonable price, but this type of small device really needs to be high quality and precision manufactured. I've lost some interest in the little EDF jobs, due to reliability issues with the Feigaos. I think I may go to Medusas if they're better. Its cheaper in the long run, and more fun too, when they hold up. I also hear they don't run a glowing temps, like the Feigaos.:eek: If that's true, then the rotors should stay on just fine, without needing mods. If you think about it, the EDF50 with a Feigao is really just at the point where the rotors start to come off. If they would run just a bit cooler, I would bet the rotors would not melt, and would stay on just fine.

I would think kits like yours would sell well, if the sheet foam came with the panel lines and color scheme printed on the foam. For one, the picture is worth a thousand words in selling stuff, and when folks know they would have a good looking plane out of the box, it add interest. The 29 looks really good, and the panel detail really sets it apart from other plain looking models.

[pmpjohn]

The production kits are cut but not printed. The CD that comes with the kits contains the graphics files for the panel lines and some details. If the builder chooses to use the graphics they need to be printed on clear Avery labels #8665 and applied during the build.

Here is a link to a detailed build thread for the Mig.

http://www.rcgroups.com/forums/show...210#post8108997 (http://www.rcgroups.com/forums/showthread.php?t=737210#post8108997)

Bill

I have not run the Medusa's yet but have disccused them with knowledgable people who have told me that performance is very similar to the Feigao's at a much reduced operating temp. I have also been told by the vendor I bought the Medusa's from that the 5300kv on 3s in an EDF50 will still need a bit of assistance keeping the rotors on.

John

[Lieutenant Loughead]

Great news! I received the replacement GWS EDF-40's on Saturday. I will take them to the office machine shop, and sand down the round edges tomorrow (Monday). :)

[Lieutenant Loughead]

Here's what I somehow managed to do to the last GWS EDF-40 unit... :rolleyes:

[Lieutenant Loughead]

Well, I've sanded down one of the two NEW EDF units, and installed the motor... Somehow the fan is rubbing against the shroud, but I can't figure out how or where -- I can't see it when it's stopped, but I can HEAR it when it's running (and see where it's rubbing when I shut the motor down).

Anyway, I must apologize for my tardiness in beginning this project. I have lots of excuses, but I won't bore you with them. :o

I will start the build this weekend. :)

[Lieutenant Loughead]

Okay -- I've officially started the build. Since I don't have any instructions, I really have to put some thought into the ORDER of the build -- I don't want to paint myself into a corner (so to speak)...

Very early on, I need to set up the control surfaces and hinges. Now, John has come up with a unique method of hinging the control surfaces -- he is using a carbon fiber tube, with another (smaller) carbon fiber rod INSIDE that tube. I'm amazed how easily the two pieces of carbon fiber turn!

Well, maybe this hinge method not new to everyone out there, but it's the first time I've seen it; and I think it's pretty cool. :)

Anyway, I cut the carbon fiber tubes to length with my trusty Dremmel tool, and test fit the carbon fiber rod inside that tube. I was amazed to see it would not fit! I think the Dremmel tool cut sort of "closed off" the ends of the tube...

So, I pulled out some 220 grit sand paper, and sanded it down. Now it's an absolutely PERFECT fit.

Next, I will install control horns, bevel the control surfaces, and glue everything in place. (While I am using hot glue for this build, I think I will use Gorilla Glue for the control surfaces -- just to make sure nothing critical "lets go".)

Also, I've had great luck with using MicroLite covering as a hinge material in my previous Depron builds. Since I plan to go with a "Top Gun Agressor Squadron" paint scheme, I can go with black MicroLite (for the black airplane), or tan MicroLite (for the desert camo airplane)... I have yet to decide which paint scheme I like best... :o

[pmpjohn]

Lieutenant

Glad to see you have everything together to give this a go. The carbon torque rod in the carbon bushing is working well in both the F-15 and the Mig-29. The Mig was maidened yesterday and is just as sweet as the F-15 but with more punch as she is using EDF50's with Medusa 5300kv Afterburners.

John

[Lieutenant Loughead]

I sure hope I can do you proud! Lately, I've been building a lot, but have not been a very successful pilot! :o

[Lieutenant Loughead]

The build continues... As I said before, I wanted to use Gorilla Glue to attach the torque rod arms to the torque rod. Gorilla Glue takes about 24 hours to dry...

I used some spare servo arms I had laying around, and cut the extra arms off. Then, I drilled out the center of the servo arm so that it would fit on the torque rod.

[pmpjohn]

Note: When and if this plane makes it into production, the kit will include laser cut plywood control horns.

John

[Lieutenant Loughead]

Well, I have the hinges done. However, since I'm new to the idea of using CF tubes and CF rods as hinges, I did not do the best job I should have...

I masked off the wing and tail, to make sure the glue did not attach to it -- all is good there.

However, I messed up and the Gorilla Glue foamed up and is now hindering the hinge from closing properly. Now, I will need to sand the Gorilla Glue from the assembly... I may end up using my Dremmel tool to grind that tough Gorilla Glue away... :o

[Lieutenant Loughead]

I (finally) found the time to use the Dremmel tool to remove the excess Gorilla Glue from the torque rod assembly. Now I'm ready to glue the CF tubes to the wing and tail. :)

[Lieutenant Loughead]

Well, I glued the torque rod TUBES to the wing/tail last weekend. This morning, I took the masking tape off, and was very disturbed by what I saw...

The glue somehow "wicked" out to the ends of the tubes, and the whole torque rod/tube/wing assembly is a single piece at this point.

The port aileron is absolutely SOLID.
The starboard aileron will move, but it's very stiff (probably too stiff for a servo).
The elevator somehow came out absolutely PERFECT. :cool:I'm going to take my Dremmel tool to this, and see if I can knock off any of the glue to free it up a little... :o

[pmpjohn]

Lieutenant

This is why I use Gorilla Glue for very few applications. It is just to hard to control. I know I did not send you any build guide but personally I use white glue to attach the torque tubes to the foam and med CA to attach the control surfaces and horns to the torque rods. I am sure you will get it all worked out.

John

[Lieutenant Loughead]

Okay guys, I've got it fixed, and I'm finally moving forward... :)

I apologize for not working on this very much in the last several weeks -- I've been building a GWS P-40 for a customer, and it was consuming the majority of my time. Unfortunately, I had to set some priorities, and the customer came out on top... :o

That build is done, so now I can focus on this one. :)

Since I have no instructions (this is an "Alpha Kit"), I have to put some thought into the order in which I do things... I quickly realized I needed to install the electronics early in the build -- because it will get covered (and inacessable) very soon!

My current delimma is how to route the wires from the motor(s) to the ESC(s), and exactly WHERE to place the ESC(s). :o

FYI -- the dark rectangles on the control surfaces are my "hinges". They are small pieces of OD Green MicroLite covering. :D

[pmpjohn]

Lieutenant

The canopy and turtle deck as far back as the cut pieces go should be a removable part. If you look closely at the drawings you will see a tounge that is glued to the bottom side front of the canopy base and slides under the fuselage top front piece. I would use magnets to hold the rear of the hatch down. This will give you easy access to the servos,rx and battery area. I normally mount the ESC's in the intake duct for good cooling airflow. On this bird I would velcro them to the inside top of the fuselage above the cheater hole for access.

Happy to see this project rolling again.

John

[Lieutenant Loughead]

I made a little progress tonight. I need to do something to extend the power leads from the ESCs to the battery...

[Lieutenant Loughead]

Oh boy, oh boy... The power system is installed, and fired up! :cool:

WOW! It's really loud, has plenty of thrust, and includes some great looking numbers:
10.32 amps, peak
10.37 volts, minimum
107.4 watts, peak
This was tested with a Tanic 3s 2220 mAh LiPo. If the airplane can't handle the weight of this battery, I may go to something smaller... :)

In any event, it looks like I'll have more than 100 watts per pound. :D

[Lieutenant Loughead]

I'm not sure why, but I don't think I've posted this yet... :o

[pmpjohn]

I have been flying the smaller stock motored jets with a 3s 450mah and the brushless with a 3s 850mah. This gives me about 5 min flight time and keeps the weight down.

Earlier someone was asking about my website. It has a long way to go but at least I have a start. Webmaster, one more skill to learn.:blah:

www.drjohnslaser.com (http://www.drjohnslaser.com)

John

[Lieutenant Loughead]

Never quit learning!

A wise man knows he knows nothing. :)

Here are some pics of tonight's work. She goes together pretty quickly, once you actually start working on the project. :o

I messed up on the elevator, and cut off a piece I thought I didn't need -- then realized I shouldn't have cut it off... I guess I shouldn't have tried to modify John's fine work! :o

I'm having some trouble visualizing how the "Fuse Side Front" pieces merge with the "Nacelle Top" -- I'm going to have to think about this one for a while. You see, I made a mistake, and installed the servos before building the fuselage -- now there isn't any room for the "Fuse Side Front" pieces (below the "Nacelle Top")... :o

John -- how critical are the "Fuse Side Front" pieces which are hidden under the "Nacelle Top"?

LOL -- I wanted to show off the EDF noise to the family tonight... Everyone was obviously frightened... Some of the younger ones covered their ears, and the cat ran out of the room as quickly as I've ever seen her run! :D

EDIT --> The last picture included with this post shows how the Depron pieces stack up to form the cockpit, turtle deck, and nose cone. When you first take those pieces out of the box, it seems like there's a LOT to do -- but when you stack them up like this, you realize there really aren't that many pieces to this puzzle. :)

[Lieutenant Loughead]

I have been flying the smaller stock motored jets with a 3s 450mah and the brushless with a 3s 850mah. This gives me about 5 min flight time and keeps the weight down.John -- my plan is to build the model, and figure out how much weight it needs in the battery compartment to balance properly. I will purchase the battery, based on that weight, but I won't purchase anything less than 800 mAh.

[pmpjohn]

Lieutenant

The lower fuselage sides form the inside of the intake ducts. Since this bird has a good size cheater hole they are probably not that critical, but they are also supposed to blend into the center spine. If you come up short you can add a filler piece.

I use the 450mah packs ONLY with the stock motors. 800 - 1000mah should work with the brushless depending on how much weight you need to balance. Might as well carry your ballast in battery.

John

[Lieutenant Loughead]

Getting pretty excited about this now! She's beginning to look like an F-5! :tc:

I'm simply amazed how quickly she goes together, when using hot glue... The next few steps will involve a lot of sanding, and I'll have to figure out exactly how to tackle that...

Once again, the majority of the time spent in this build is thinking how to accomplish a step -- there is very little time involved in actually performing that step! Kudos to John (and his laser cutting machine) for such fine work! :)


Pic #1: Really starting to look like an F-5 now!
Pic #2: Another angle.
Pic #3: This angle shows how much of the duct work I cut away to make room for my poorly placed electronics (sorry John!). Also -- check out the awesome curves on this airplane! :ws:

[Lieutenant Loughead]

Oh -- and can I just say the battery tray is HUGE?!?!?!?! :eek:

[Lieutenant Loughead]

Heroes was on last night, so I didn't get much done... :o
Pic #1: I beveled the inside of the battery hatch, so that it could make the proper curve. I hit it with a little hot glue, and then taped in place while the glue cured. Afterwards, I applied a little more glue, to make sure the bond was good.

Pic #2: I beveled the aft end of the battery hatch, so it would fit the turtle deck properly.

Pic #3: The entire battery hatch (inverted).

Pic #4: Battery hatch, taped in place, with glue curing.

Pic #5: An idea of the size of this model.

[Lieutenant Loughead]

I apologize for this project's slow progress... I went on vacation last week, and life has been hectic in general...

However, I was able to spend some time sanding the cockpit, while at my son's soccer practice last night... Several people came up to me and asked what I was doing. :cool:

I am including some pictures of the current status of the project.

I still need to sand the nose cone, and then sand all the edges of the fuselage down... Then, I need to add decals, paint, and find a way to secure the battery hatch (I'm thinking of using a rubber band instead of rare earth magnets this time).

Somewhere in all of this (probably just after sanding the nose cone, and glueing it to the fuselage), I need to figure out how much weight needs to be in the nose to achieve the proper CG. With that information, I will know what battery to purchase.

It's getting cold here... We're expecting our first freeze of the season sometime next week. By the time I finish this build, and receive the battery (mail order from China), I'm afraid it may be too cold to maiden! :eek:

[Lieutenant Loughead]

A little more sanding, and the nose cone is complete. Wow... I must admit, I'm very happy with how the nose cone looks! :eek:

I'm going to need to add a little foam to the inside corners of the fuselage -- when I sand the edges, I don't want to sand all the way through the fuselage!

Also, I think I might try to remove a little weight from the nose by using a Dremmel tool to remove some foam (to hollow out the nose cone)...

I ordered the Loong Max 3s 1000 mAh LiPo batteries this morning. :D

[Lieutenant Loughead]

Sanding and spackling is done. Now, I just need to:

Find a way to secure the canopy (maybe rare earth magnets after all).
Paint or cover (I haven't decided just yet).
Final photo shoot.
Maiden!My son and I played with the black glider in the front yard this afternoon... The airframe glides really well -- if the maiden goes bad, it will be solely on my shoulders... :o

[pmpjohn]

Looking good Lieutenant

John

[Lieutenant Loughead]

The canopy is secure -- the rare earth magnets are installed.

I used four "D21" magnets from www.kjmagnetics.com (http://www.kjmagnetics.com)

[Lieutenant Loughead]

The covering is applied... Now I need to start painting the rest of the airplane black... ...then again, maybe black covering would be easier... :confused:

One picture I failed to take is of the bottom of the aircraft -- there is a big red star on the bottom of the wing -- to aid with orientation. :)

I discovered that a normal, everyday paper towel tube (or toilet paper tube) is a snug fit on these little 40mm ducted fans. See the pictures below. :cool:

[Lieutenant Loughead]

I discovered that a normal, everyday paper towel tube (or toilet paper tube) is a snug fit on these little 40mm ducted fans. See the pictures below. :cool:I found an alternative to the paper tube ducting... "Round Thin Wall Tubing (http://www.visipak.com/tube_packaging.shtml)" from Visipack:Nominal size: 1.5"
Inside Dimension: 1.656"
Outside Dimension: 1.680"
Wall Thickness: .012"

This is really good stuff; however, I think I'm going to stick with the paper tube for this build -- mainly because I already have it painted, and I need a little more weight at the tail. :) (I bought a slightly heavier battery than I wanted to, and the paper at the tail should help balance it out.)

I don't want to post a picture just yet, but I've started painting... The top of the airplane has the first coat of paint. I will be applying the second coat of paint (to the top) today, during lunch...

Then, I will paint the bottom, and we'll maiden this beauty! (Though I'm still waiting on my battery!)

[pmpjohn]

If you find that you want a bit more zip than the straight pipes give you, the template I sent with the kit will give you a 90% FSA exhaust. This is normaly a good compromise between maximum static thrust and maximum eflux velocity.

John

[Lieutenant Loughead]

The final coat of paint is drying now.

...now, if I could only get that BATTERY order... :rolleyes:

EDIT --> It looks like they mailed it today (one full week after placing my order)!

[Lieutenant Loughead]

Just waiting on the battery now... :)

Actually -- I noticed the hinges are a little "sticky" after painting... I'm going to use this "down time" (waiting for the battery) to correct this. :o

[pmpjohn]

She looks pretty menacing in the black aggressor scheme. I hope you can see the big star at a distance. Not sure I could. Anyone interested in swapping a pair of young eyes for a pair of bifocals? I can't wait to hear the maiden report.

John

[Lieutenant Loughead]

Luckily, I've had 20/10 vision most of my life... :cool:

I was recently tested, and my vision had declined to 20/15 vision in my left eye... :(

[Lieutenant Loughead]

Ugh -- I'm still waiting on the battery... Tomorrow looks good for flying, so if the battery gets here today, I'll try the maiden tomorrow. :)

While I've been waiting on that battery, I swapped out the Hitec Electron 6 receiver for a Spektrum AR6100 receiver. This allowed me to use my computer radio to set my endpoints -- I was getting some "3-D" type throws, and wanted to bring them back to something more realistic. :)

[Lieutenant Loughead]

WOOHOO! The battery is here!

I'm including a few pictures of the battery in the F-5, exactly where it needs to be for the CG to be right.

The good news is that I probably could have chosen a slightly heavier (larger mAh or higher C rating) battery -- there's room to grow! :)

So, the wind is supposed to be strong for the next few days -- but she's ready to maiden when we have a nice, calm day. :D

[pmpjohn]

I'll keep my fingers crossed for calm air. What did the AUW come out at?

John

[Lieutenant Loughead]

Just put it on the scale for you. AUW is 15.15 ounces.

[Lieutenant Loughead]

I tried to maiden the F-5 on Saturday morning -- the weather was perfect for it. However, I had to scrub the maiden becuase that starboard aileron is still not working properly. I thought I had it fixed, but it flared up again during preflight... I didn't want to risk the airplane...

I went home and discovered the pushrod was slipping in the E/Z connector at the servo arm. I went back out to the field, and performed the maiden Saturday afternoon.

I threw the airplane roughly six times, with the same result every time -- there is not enough power to climb. I can maintain level flight as long as I want to, until I decide to turn -- in which case she descends. I did try moving the CG back, to see if that would help -- no dice.

The airplane has no damage.

Unfortunately, this F-5 was expirimental and the expiriment didn't work. :o

I will be happy to entertain any ideas on how to get this airplane to climb! :o

[pmpjohn]

You could remove all the paint and hot glue and put her back together with CA. That would save some weight. I don't care for props on the back of jets but that may be the only way to get this one to fly right.

Or if you want something that we know will fly with your fans try my F-15 or Mig-29. They come out at around 8oz and are good for about 50mph with the 5800kv motors on 3s.

John

[Lieutenant Loughead]

I don't care for props on the back of jets but that may be the only way to get this one to fly right. Now, THAT's an idea... I just happen to have a motor laying around that may be a good fit for "pusher prop" use... :)

[Lieutenant Loughead]

Hey guys -- I didn't realize I haven't posted here since 11-22-2007...

I've put three different motors on the back of the F-5A. I know Dr. John won't be happy with a pusher jet, but I've been enjoying the heck out of it.

With the short, stubby wings of the F-5A, I figured this airplane would be very difficult to fly -- very fast, with a very high stall speed... However, the opposite is true -- this airplane flys just as good fast as it does slow!

Landings are amazingly easy, and launches are just about as stable as any other airplane I've ever tossed into the wind.

The airframe design is a winner -- we just need to work on the power system. :)

[pmpjohn]

Lieutenant,

I am working on the power system problem. I am happy to hear that the basic airframe flies well with enough thrust. As I stated from the begining I was a bit skeptical that two 40mm GWS fans would have the punch to fly this large an airframe.

I am about halfway through a beta build of the same design scaled up to fit a pair of WeMo 50mm Microfans. The microfans will take a 24mm motor where the GWS 50mm fans are still limited to 12mm motors. The 12mm motors are good for about 80 watts. An HET 240/15-6000 in a micro fan is good for 300 watts x2 = 600 watts.

The airframe now has a 30" WS and a length of 50". All the foam parts with some sanding left to do weigh 272gr. I am shooting for a power loading of 250+ watts per lb.

John
www.drjohnslaser.com (http://www.drjohnslaser.com)

[Lieutenant Loughead]

Sweet. :D

[pmpjohn]

Here are a couple of pics of the 50mm fan version of the F5A. Fans and thrust tubes are ready for installation. Servos, linkage and ESCs are already in. I am hopeing for a maiden this weekend if the weather will co-operate.

John
www.drjohnslaser.com (http://www.drjohnslaser.com)

[Lieutenant Loughead]

Hey! That looks just like mine! (only bigger!) :D

Best of luck -- I think you'll be surprised how slow it will fly! :cool:

[pmpjohn]

Lt.

I will not have any problem if she flies slow as long as that is not the only way she flies.

John

[pmpjohn]

The build is finished. With two WeMo Micro fans, two HET 240/15-6000 motors, two Dualsky 40 amp ESCs, three HS55 servos, an AR6100 rx and a 3s 3700 mah Vampower Platinum 25c lipo the AUW came out to 854 gr or 1.9 lbs. With 300 watts per fan that gives me a power loading of 315 watts/lb. I think she will fly. The wind is predicted to lay down this weekend so we should find out.

John

[Lieutenant Loughead]

The build is finished. With two WeMo Micro fans, two HET 240/15-6000 motors, two Dualsky 40 amp ESCs, three HS55 servos, an AR6100 rx and a 3s 3700 mah Vampower Platinum 25c lipo the AUW came out to 854 gr or 1.9 lbs. With 300 watts per fan that gives me a power loading of 315 watts/lb. I think she will fly. The wind is predicted to lay down this weekend so we should find out.Wow -- 1.9 pounds! When I first read that, my jaw dropped. Then I realized I've been flying 40-ounce GWS P-38's... (40 ounces = 2.5 pounds) See my avitar for a picture of the maiden lauch of my first 40-ounce P-38...

I'm very excited about this -- please keep us posted! :D

[idealhobbies]

/ very interested.... keep it coming.

[Lieutenant Loughead]

The wind is predicted to lay down this weekend so we should find out....and the verdict is?

[Lieutenant Loughead]

Hello? What happened with this F-5?

[pmpjohn]

Sorry about the delay in further reports. The numbers looked good so I was pretty disappointed in the actual performance. It took full throttle to climb at all and the power systems will not live long at WOT. Thinking she was loosing it in the long intake ducts I cut cheater holes in the bottom but saw very little improvement. She has now been gutted and the gear moving on to other projects.

John

[Alpea42]

I know this is O T but you did say you flew it as a pusher.I am building S. Shumates T-38 Talon as a 120% sized pusher and it is also like the F-5 a cool jet. S Shumate says at 26 oz. AUW I am at the upper end for wieght limit and I might should try it with coupled flaps to elevator.It has a Turnigy C3530-1700Kv motor ,APC 8x6 prop, 45A esc and a 2250 m.a. 3s 25c Lipo bat.My w.s. is 34" and lenght is 53"