Ultrafly Hawk EDF Conversion

[Ed Waldrep]

Well I got the Hawk yesterday locally and my internal instinct to put a fan unit in it got the best of me and I started cutting on it after staring at it all day. There's not enough thickness for a Wattage fan so a wemotec Microfan will be used. I'll still have to remove about 3/16" of foam on the inside where the fan will mount (right behind the wing trailing edge). I've been hogging out the foam with a sanding wheel and dremel, but I've also been contemplating cutting the fuse into sections and so I can attach foam cutting templated to remove the required foam. I plan to use photo paper inlet ducting with the inside wall made of 1/16 balsa. I'll add a balsa bulkhead in front of the fan to attach the ducting to. I'll have to modify the aileron servo location, either by laying it on it's side or running a cable to the ailerons, or use two aileron servos. Having room for the torque rods sticking up is the problem, I want to keep the fan low in the fuselage to make the exhaust duct easier.

Yeah I know I should just fly it with a pusher prop but what can I say I'm and EDF fan, and wont have to worry about getting my fingers chewed up either!

I'm looking at the Himaxx 2025 4200 or 5300 on 3S lipo, but I'm not sure what the 4200 pulls in the microfan. I want to get as much power as possible without melting the motor. I know what the 4200 pulls in the Wattage fan but the microfan I have no data before. I'm using the search but there's a lot of info there to sort through. I'd like to be pulling about 175 watts or so, maybe more if the motor can handle it. The reason for the 2025 instead of the 2015 is the greater heat absorbing ability (more mass) of the 2025 vs the smaller 2015. I'm guessing the 2025 4200 would pull about 12 amps or so on 3S lipo but not sure. Jones boy reported on12 cells the 2025/microfan pulled 15 amps. The 5300 might pull over 20, maybe to much for the motor. Also I'm wondering about a heat sink, what did you microfan flyers finally find for that?

[Wof]

Any pictures Ed?

[Ed Waldrep]

No pics yet, not much to show anyway.

Found some data on 2025-5200 and 3S generation 1 TP lipo 2100, Jer Jer posted a 17 amp draw in the microfan.

I bet Dave Morris has data, he said in an earlier thread he had the motor and was going to test it, but the results must be in a different thread. More searching....

[AirX]

Hi Ed,

I am using a clone of the 2015 in the microfan and it works well, can't give you any details yet, the Astro Wattmeter I ordered is not here yet. It is the 5300kv version.
I guess I should get a heatsink for it since you think it might be too much load on it.
I am using the Kokam 1500hd 8c pack with it. Dave and Joe(Wireit) have given it a run in thier testing but I did not save the figures.

This plane does look good doesn't it... :)

Eric B.

[U812]

Go Ed go.

Or is that? Go! Go! Go! :D

Steve

[Gordito Volador]

Two thumbs up for Ed! I'm following this one closely. Can't wait for pictures, I have a few micro fans sitting around looking for work. :cool:

Regards, Bill

[U812]

Ya Ed, start with the pictures would ya?

Steve

[Ed Waldrep]

Can't take pics at work!

Gee Steve, you are jumping with enthusiasm, time for some DC for you! I might play some tonight, but gotta get home at 9 and go ride my bike, maybe play at 10 pm on the gamespy basrah server. Probably be to tired though from the bike.

Well with the data I got on the 5300 from that one post I went ahead and ordered the 2025 5300, hopefully I'll get it this week, want to fly the jet this weekend.

[U812]

Ed,

Put me on your Buddy list so you can find me if I get to it tonight. Promised the wife I'd watch a movie with her though so it would be around 11 pm.

Ah i just like that plane it looks nice for a foamie. Was thinking about getting one to and doing the same thing. I'm all eyes watching you.

Hey you got the F-22 working good. this should be a lot better and it also looks like the plane unlike the F-22. Funny thing is that Wattage F-22 did have washout! LOL



Steve

[Ed Waldrep]

Yeah, I'm a bit worried about this Hawk wing, no washout. I can add drooped leading edges after the initial flight as I explore the flight envelope.

Are you using U812[EDF]?

[U812]

Yep...I am and yours again so I can add it?

Hey, it's a foam wing. Can't you twist it a bit?

Steve

P.S. Actually I believe on game spy it's U812EDF.

[Ed Waldrep]

The ingame name is all that maters...I use All Seeing Eye and it has a search function
Mine should be Crazyy Ed [EDF]. I'm not sure about the spaces though, I'll have to check.

[U812]

Thanks Ed, when I find you I'll add you to the Buddy list so I can find you through Gamespy.

Steve

[the Swamp Fox]

Cool,

Hope ya done mind if I lurk about here and try to learn something..

Hehe, funny y'all play DC..I got BF42 upon release and played ALOT
including the mods...DC is cool...don't play much anymore..

One of the best all time moments in gaming I had was in the "eve of destruction" 'nam Mod...

We were in a fully loaded huey coming in ..I was second inline to jump out.
1st guy jumped..we were too high! Splat.. then as we lowered into the LZ a VC with a RPG popped up from behind a bush and put a round right in the door :WHOOSH!!

Got all of us...

next round I played VC and emulated that tactic with great success..took down a fully loaded huey myself :)
too much fun...time to make some room on the HD !

Can't wait fer some pics on this conversion.

[Ed Waldrep]

Well I ordered the Himaxx 2025-5300. I was having second thoughts and wanted to change it for a 2025 4200 for my K&A Parkie F-86, and bought a EFLight 370-5400 on the way to work, but saw after reading the instructions that it was limited to 8 amps max. I don't think it would last long at my hoped for 175 watts, so I think I'll take that one back and just wait for the himaxx, should be here Thursday.

The conversion is going to be a pain in a way, sanding out foam is kinda tedious. Hotwiring would be easier, but would require cutting up the fuselage. I need to remove enough so I can fit in the photo paper inlet ducting.

[Synwpn]

Ed, you had the right idea to stick with the Himaxx 2025-5300. i was putting 264 watts through it on my Mig15.

[U812]

Well I'm putting 400 watts through a Hacker B20-12L. Yikes!:eek:

It's still alive with a little throttle management. And that's with a micro fan. It's amazing the blades are still on. In the F-104 that's about 300 watts per pound!

Steve

[Ed Waldrep]

Well I haven't flown it yet, still some work to do but I should be able to finish it today. I really need to get back on my midi T-33 project, lots of work yet to do there to get ready for Arizona Jet Rally in November.

The first shot shows the left side inlet ducting (the balsa sheet is the inlet liner wall) and the main inlet ducting. The front of the fuse is to the left and the right is the rear.

The second shot shows the fuselage joined and the front inlet ducting installed, as well as the left inlet foam piece installed. In the foreground is the blue foam block with templates attached that I will use to cut the right side inlet piece. The stock inlets were very close to scale in size but that doesn't work well for EDF so I cut off the stock inlets even with the leading edge of the wing and added these foam inlets to replace then.

The third shot shows the microfan installed in the fuse at the trailing edge of the wing. I had to cut an access hatch to install it. Fitting the exhaust ducting was a pain, I made it a bit too small in diameter. I glued two ply rails on the microfan to help mount it, and ground off the ring around the microfan. I probably should have made troughs in the foam for the ring, it would fit, and grinding it off made the fan housing a bit too flexible for my liking. I guess I'll find out if it rubs on the rotor. I like having the mounting rails. I've seen others use two bulkheads to hold microfans in place, but then how do you secure it? Plus you'd have to slide it back to remove it, meaning a bigger hatch is required. More than one way to skin a cat I guess.

The fourth shot shows the stock inlet cut off and some foam has been removed to form the inlet...the hole on the inside wall was covered later with a piece of cardstock attached with 3M 77 (old formula). All the inlet ducting was made of cardstock/photo paper.

The fifth pic (sorry these are kinda out of order as far as construction goes) shows the forward inlet ducting cardstock installed, without the balsa inlet liner wall. This ducting method was inspired by Kevin Cox's F-18 design. I've done paper inlets for my Wattage F-22 conversion a couple of years ago after a rebuild and they works great. It can be challenge fitting the pieces in place though, especially on this project, after the fuse was joined, getting the other side front ducting and the liner in was challenging.

This isn't a project for the faint of heart. I should have built it stock but hey I like EDFs, what can I say. Removing the foam on the inside of the airplane was a pain, a dremel works but controlling the cutting depth is tough. I wrapped sandpaper around a 2 inch diameter accelerator bottle and that made sanding the inside of th fuselage easier (80 grit paper). I had to remove about 1/4" of foam from either side of the fuse on the inside, leaving a wall thickness of still about 1/4" or so.

Another way to convert this would be to fill the fuselage with expanding foam to fill up the voids, then cut the fuselage into setcions and hot wire out the ducting. That'd probably be easier in the end, but of course you'd have to fill in the cut lines on the outside. A glassing job would help cover that and give a nice durable finish, but I'm not sure on the final weight. The addition of the ductwork has probably added less than an ounce, and with the light brushless motor and lipos I'll probably be no heavier than stock weight.

If I wanted another Hawk I'd probably scratchbuild one from wire cut foam, it'd be easier in the end! Me and my conversions, I'm hardheaded!

[Ed Waldrep]

Here's a shot of the inlet ducting liner extending through the inlet. I had to trim it even with the front of the foam inlet (where the cut line is) because the angle changes there. I didn't apply any liner to the inside of the blue foam new inlets but may later to smooth it out.

Next is a shot looking down into the inlet with ducting and fan installed. Kinda fuzzy but I think it's clear enough.

The third shot shows where foam was removed (sorry didn't take a before and after shot). The black marker lines show the trough that has been sanding into the foam to make way for the inlet liners.

I though of just using the foam itself for the inlet, that would be lighter, but there were areas on top and bottom that would have needed to be filled in so I just went with the paper. The paper though required me to have balsa bulkheads to form the paper into place. That's the fourth shot.

The last shot shows the main inlet tube installed between the two balsa bulkheads. It was formed by wrapping the cardstock around the 2" diameter accellerator/kicker refill bottle (I think it's Bob Smith industries brand but I'm not sure, tore the label off of it)?

[Tram]

Looks good!

[JetMang]

Cool conversion Ed. I'm curious to see how it goes in the air.

Chris

[Synwpn]

nice! what do you project your auw to be around?

[AirX]

Very nice work Ed, you da man... :)

Eric B.

[dave morris]

wow Ed that looks like a lot of work. I pretty much have settled on only razors or hackers in fans, I like the razor 2500 5s micro fan and the hacker 2026L for the VASA55. I did not have much luck with himax motors, seem to draw a lot of power for the amount of work they did, but they are inexpensive! The razor has the main advantage of light weight, even with the required heat sink.

I agree with the comment about being able to build one from scratch easier. Your not limited by an existing design.

Keep at it looks like your getting close.

[Kevin Cox]

Nice Ed,
I missed this one.

[U812]

Ed,

Make one for me would ya.:D

Great job man,

Steve

[jet_jer]

Ed - You will like that motor fan combo - I am still flying that setup around my park in my micro L-39. If you need any help or more data just let me know.

Good luck with this.

Jer

[Ed Waldrep]

Well it flew! Just before dark (it was really to dark to fly a white airplane with no dark colors on it) if chucked it off the side of this gravel pit to give myself some reaction time. It was nose heavy, had full up trim eventually and still dropping. It's loud, that microfan is screaming. I'm pulling 230 watts at 22 amps on 3s lipo. It feels like it wants to fly out of my hand, hand launching shouldn't be much of a challenge when I get the tail weight in or move the battery back. It's fairly fast and has decent vertical but I didn't have a lot of time to fly it, it was so hard to see I was worried about getting it back. I launched off a lower level and had to climb back up a few feet to land on the road...and of course I slipped and fell on my side as I was going back up the hill, but I kept my eyes on the airplane and saved it. Finally got to the top and landed on the street, scuffed elbow and all. I got a chance to stall it, didn't seem to drop a wing. I added NASA drooped leading edges to about the last 4 inches of the wing, they seem to work. I may pull them off later, may not need them, but I didn't want to risk a first flight possible bad hand launch and tip stall without them. I've read the wing has washout so maybe I don't need them, just extra insurance.

I should have put some dark tape on the bottom of it, boy it was hard to see, had to keep it in the western sky in the fading light but still hard to see! I did let a few woo hoos out when I got down though, so I must have had some fun.

[U812]

Cool Ed. It's all that DC. Really sharpens the old reaction time. Lets see some video next time.

And they don't call you crazyEd fro nothing!!!LOL

Steve

[Synwpn]

cool! congrats Ed! going to paint paint her up now?

[U812]

Hey!!!!!!!!!!!!!!Where were yout tonight? You missed all the killing!

Steve

[Synwpn]

hahah, got home late from work. had to fight traffic since the Wahine's volleyball game at the university (up the road) causes ugly traffic around here.

but i'm looking to go play now. :D

[AirX]

Congrats Ed,

Post some pictures of it after you have it presentable, the basic shape of the orriginal kit looked great so if you were able to keep it looking as good then it was a success in every way.

Cheers,

Eric B.

[the Swamp Fox]

Cool ED,

I've fallen once or twice while flying myself..hehe,glad I'm not the only one.

So cool you pulled it off,but not suprising.

I built and flew mine as a pusher ..

has loads of wing flex with AXI / 3s power

I kept propping up and eventually got bit...

talk about a bad handlaunch...
I flew it until the radio was too slippery with blood..
that's the shirt I was wearin' and that aint paint :(

[Steve C]

Wow, sorry to see you got bit...but I still have to laugh. Who else but an R/C modeler would think to grab his camera and take a picture of his ruined shirt before the blood dried! :)

Ed, I also bought one of these for the purpose of converting it. I didn't realize how narrow it was until I got it home. Great job :D

Steve C

[Ed Waldrep]

Thanks Steve C. Hope my pics help. Filling it with expanding foam and cutting up the fuse and using templates to cut the ducting might be easier but then you have to fill the cut lines...pros and cons to both ways of doing it.

I flew it twice again today, and it was very windy, 25 to 35 mph. My landing was near VTOL! It got bumped around pretty good but handled it ok. IT'S LOUD, with that microfan screaming it's sounds like a mosquito on crack! I probably should have balanced the fan but I don't think I could do much to quiet it.

[jet_jer]

Congrats Ed - I had no doubts!

Jer

[roccobro]

Whats the AUW at? Is the Himax getting hot at all?

Good job Ed!

Justin

[Ed Waldrep]

I guess I never posted pics of the finished airplane so here ya go. It flies ok, loops from level flight are no problem, but it's far from unlimited in the vertical performance. At 230 watts I'd expect more performane but it is a tiny little fan and I don't have huge intakes. There are some sharp curves in the ducting due to them being made of cardstock but oh well.

The stall is very benign and gentle, it doesn't tip stall at all. If I put it into a steep bank and pull full elevator, it will roll level and oscillate as the wing stalls and unstalls. That's really nice, some planes will roll over in a death spiral. I added drooped leading edges with some fan fold foam, but they aren't very big and the sawtooth they create in the wing is a bit dented and not sharply defined. I may take them off and see if the stall is the same, if so then it's a great wing design.

[Ed Waldrep]

Whats the AUW at? Is the Himax getting hot at all?
Justin

The all up weight was about 17 oz before the crash, a guy made a bad hand launch and I had too much up trim and it stalled going straight up, coming down on the nose. I repaired it somewhat and added a carbon arrowshaft segment to the bottom, if it happens again the nose wont break, that shaft will spread the load out across the fuselage. I only launch myself now, should have known better. Girly throws not allowed, although I'm told I stop then throw it. People get a big laugh.

If I had to do it over again I probably would just cut a new fuselage out of blue foam and cut the ducting into it. Having to add the paper ducting was a pain. Maybe expanding foam would work, to fill in all of the voids, then hot wire the ducting, but expanding foam is polyurethane, and cutting that with a hot wire produces toxic fumes!

We need more cheap foamie edfs on the market, conversion is a pain. Put ducting in from the beginning, and give the option of edf or pusher.

[JetMang]

Here are some in-flight shots I took of the airplane at the last AZ jet rally. THis airplane is a little screamer. It's quite impressive considering the size of the airplane and fan.


Chris

[Ed Waldrep]

Thanks for the pic Chris, I didn't know there were any. I had fun flying it at AZ, it was a nice backup plane since my others got trashed.

[roccobro]

Sounds great. I figured the conversion was going to be a pain when you experts were running ideas back and forth a while back. Thanks for getting back to this and the pictures with flgith report!

Justin

[Albert_Moto]

nice EDF mod !!

I got a Ultrafly Hawk too . . . which EDF are u using that can support 2025-5200kv BL motor at 3 cells ?

Albert
www.aero-fever.com

[Ed Waldrep]

Albert, it's the Wemotec Microfan (50 mm or 2 inch diameter) using the Himaxx 2025 5300kv motor and a Phoenix 25 controller and 3S 2100 Thunderpower lipos (gen 2 at the time). I had some sort of shutdown several times due to I think high amp draw. Sometimes right off the charger, when I first throttled up, the motor would get to full throttle and then shut off. I think the amp draw must have shot way up on the initial startup. After I brought the throttle back to idle and brought it back up slowly, maybe three or four clicks from full throttle, it would keep running. I did have some thermal shutdowns also, at least I think they were. The controller was running behind the receiver in the turtledeck and didn't get as much air as it wanted, so I had thermal shutdown a few times and landed out in the gravel at different fields. The bottom of the plane has road rash, I added some lightweight spackle but stopped flying the plane after that, needed the components for something else. The shutdowns were strange, sometimes I'd go grab the plane and the motor would come right back on, and sometimes it took a minute or two. One of the motor wires was cut a bit during installation so maybe that caused a problem of some sort. The motor was pulling 23 or more amps if I remember correctly, maybe a 35 amp speed control would have been better, or put the controller behind the motor.

I'll have to put the controller back in and fly the thing some more, if I can ever get my other projects done.

[roccobro]

Others have reported the same thing with their P-25's in the Alfa's. CC says to shut off the current limiting for all EDF applications to eliminate that problem.

Still a nice conversion Ed!

Justin

[Ed Waldrep]

Thank Justin, it is a fun little plane, it needs to fly again. The amazing thing was how it wouldn't tip stall....full up and it just settled to a level attitude and rocked side to side. Not sure why, it's a thin tip airfoil, not sure about washout. Maybe I'll bring it to the Best In The West jet rally in April, are you going? It's in Indio somewhere, not far from you I think, 30 or 40 miles?

[roccobro]

I'll put it on my calendar now. I don't know what my work schedule will be then yet. Sounds like fun!

Justin

[Albert_Moto]

Ed, we really get rid if CC ESC's power-cut problems !! It always happens in my friends' EP Heli too !!

Not only on Phoenix 25, but also happens on Phoenix 10 & 35. Some of us change to use the Align and Otter ESC now.

Albert
www.aero-fever.com

[roccobro]

Just turn off the overcurrent protection and you can still enjoy the best American or other made ESC available.

Justin

[Kevin Cox]

I haven't had any problems with CC25's. 2 in the Banshee and one in F-35.