Official Freewing F/A-18C Hornet 90mm EDF Thread

[Aros]

Hmmm, I've never messed with throttle expo curves before...Is there a tutorial, aka "Throttle Curves For Dummies"? I have a DX18...I would like to try this out myself. Thanks for the info!

[Airguardian]

I think I've actually got to the issues, I downed tools yesterday afternoon and went to the field. Got 3-flights in on the F-18 (5 on the L-39)

I put a 50 % exponential curve on the throttle (see photo below):

So, my conclusion is that given the power those motors are putting out, I must have inadvertantly been using much more throttle than I actually needed most of the time.

That's more like it!
Glad you sorted it out!

The expo curve idea is interesting although I'm more or less happy with mine being linear but may try it some day, FWIW. :)

[DCORSAIR]

Yeah me too, interested in the expo throttle curve, something for sure I have never tried before, very interesting and I see your using Futaba like me so your info would be easy setting that part up.

[Hugh Wiedman]

Thanks Jandro 👍

I think I've actually got to the issues, I downed tools yesterday afternoon and went to the field. Got 3-flights in on the F-18 (5 on the L-39)

I put a 50 % exponential curve on the throttle

After around 3-minutes 30 seconds I landed with 60% left in the battery (I really didn't expect this). So with some mixed flying I reckon I can get over 5-minutes out of her

So, my conclusion is that given the power those motors are putting out, I must have inadvertantly been using much more throttle than I actually needed most of the time.

I suspect it's something to do with the power / rpm band for that motor/fan setup, a little like a the sweet spot on 2-stroke sports bike if I might use that analogy.

I'm going to use the same 50% throttle expo on the A-10 and am hoping it will significantly prolongate my flight times on that, in fact, I'm more optimistic that I will see a more dramatic change with the A-10.

Based on limited testing I would recommend people experiment with this, you can't really do any harm and with an exponential curve you've always got full power at the top of the sticks.

It's not been something I've done before on EDFs (I have done it on certain turbines that have had very distinct power band traits or spool-up characteristics but that is irrelevant here).

Famous last words I know, but I was really surprised by how she handles, in a good way, I really pushed my luck a couple of times (deliberately) flying close to the stall and she so far hasn't taken the bait. Not sure I'm going to move the CG back any further for now, for me she seems to sit on her tail nice enough in-flight (it's currently at 101mm).

Anyway... problem busted 👍

Andy

Veeery Interesting! Great that you got it worked out, knew that something was amiss on the short flight times, but I never even knew you could put expo in on the throttle. I'm using a Spektrum TX and never saw anywhere that I could dial in expo there, but then there's a lot of things on the TX that I have never fiddled with, so it could be there.

[Aros]

My buddy Perry showed me throttle curves today...It's stupid easy to set up but I still need to see it in action so I will try it out on a model I don't worry about if something happens to it just to see the effect in action. I love the idea of it and I can totally see how it can help manage battery life.

[DCORSAIR]

My buddy Perry showed me throttle curves today...It's stupid easy to set up but I still need to see it in action so I will try it out on a model I don't worry about if something happens to it just to see the effect in action. I love the idea of it and I can totally see how it can help manage battery life.

Yeah, I might try it also, I have a 3 yr old 80mm F-86 beater jet I might just try it on...

[Aros]

Perfect!

Nice sorties today...

[Hawk4me]

Anyone able to tell me if the carbon fiber rails in the battery bay will affect RX/TX signal at all? I relocated my receiver to the front just above the gear and I can't seem to get a good spot to put the antenna of my receiver without getting it close to that rail in the fuse. Got a satellite for it that will go up in the nose section and face the same problem up there.

[Elbee]

Anyone able to tell me if the carbon fiber rails in the battery bay will affect RX/TX signal at all? I relocated my receiver to the front just above the gear and I can't seem to get a good spot to put the antenna of my receiver without getting it close to that rail in the fuse. Got a satellite for it that will go up in the nose section and face the same problem up there.

You won't have any issues with the CF rods the way you described your install. Do remember, though, CF will conduct electrons. So be aware of wire abrasion or open connectors. Best, LB

[The43rdHammer]

Perfect!

Nice sorties today...

I loved this.... all you needed was some white smoke 👍

Cameo performance from the pesky wheel stuck down, I think it wanted to be the star of the video. Never work with children, animals or retracts!

Andy

[The43rdHammer]

Hi all, so I was messing around with my (old) DX6 and came up with this curve, which I think is similar to the one I have on my Futaba, for Futaba users an EXP2 curve of 50% worked best for me, lower curves reduced the benefit exponentially (pun intended):











I think I'd maybe try something around 30% throttle @ 50% stick to begin with:



Andy

[Hugh Wiedman]

The43rdHammer Andy, you hit the nail on the head, just checked my DX9, same thing, looks pretty simple to set up. Thanks for your investigations, Mr. Holmes!

Just not sure if I'm ready to give it a try and maybe Aros has an idea of trying it out on a "disposable" aircraft (hmmm, now which one is going to be the guinea pig?) Only concerned that I'm so used to throttle placement with my fingers (my visual judgement of actual airspeed kinda sucks in windy conditions), especially on landing approach and landing that I'll be too slow at the lower end of the throttle curve that I'll end up with a wing stall, and the F-18 is not a fun airframe to wing stall at low altitudes. Obviously it worked great for you on battery management but doubt I have the same skills. Interested to hear how it works on your A-10, but since I'm already getting 5 minutes on that and 4 minutes on the F-18, will probably just leave those as is. I used to be able to get an additional indication of EDF "speed" with the older fans from their whining noise, but since I've converted all my 90 mm to the 12 blade inrunner, it's not quite as noticeable.

[The43rdHammer]

The43rdHammer Andy, you hit the nail on the head, just checked my DX9, same thing, looks pretty simple to set up. Thanks for your investigations, Mr. Holmes!

Just not sure if I'm ready to give it a try and maybe Aros has an idea of trying it out on a "disposable" aircraft (hmmm, now which one is going to be the guinea pig?)

🤣 absolutely, nobody should do anything they feel uncomfortable doing, just following up on my previous email(s).

I suspect this is more relevant for those of us out there with 9-blade inrunner setups (80mm or 90mm).

Things were twitching that shouldn't have twitched when I tried it, but then again I felt like I had nothing to lose at the time and had at least had some experience with it on other fixed wing aircraft.

I did try it on my trusty L-39 beforehand.

Andy

[Aros]

I loved this.... all you needed was some white smoke 👍 Cameo performance from the pesky wheel stuck down, I think it wanted to be the star of the video. Never work with children, animals or retracts!

LOL, right? I just wanted a nice view for folks and as I upload the video I was like, "Ah, come on!!"

[The43rdHammer]

Aros meant to say, great job on the Friday Cameo ... guest starring Todd Breda the Viper Dunkin' Raider... 👍

Andy

[Aros]

LOL!

[Cape Jets]

So after seeing much debate on power for the F-18 ( 9 Blade vs 12 Blade) I have decided to upgrade the Blue to 12 blade. Question is which one. Here are the choices: Freewing 90mm 12 Blade 4068-1835kv @ $158. ( Hugh Wiedman's favorite 90mm) the FMS 90mm 12 Blade 4068-1850kv @ $116. or just for interest the Taft Hobby 11 Blade 3674-1500kv @ $73. The Freewing weighs in @ 530gr and 3900g thrust, the FMS weighs in at 560gr (the heaviest) 4000g thrust and the Taft weighs in at 430gr and 4400g thrust. On paper the Taft is the way to go. Lighter and more thrust and way less expensive.(but only 11 blade vs 12 blade) So please add some confusion to my decision and pipe in on the pro's and cons for each. Thx.....

[Hugh Wiedman]

So after seeing much debate on power for the F-18 ( 9 Blade vs 12 Blade) I have decided to upgrade the Blue to 12 blade. Question is which one. Here are the choices: Freewing 90mm 12 Blade 4068-1835kv @ $158. ( Hugh Wiedman's favorite 90mm) the FMS 90mm 12 Blade 4068-1850kv @ $116. or just for interest the Taft Hobby 11 Blade 3674-1500kv @ $73. The Freewing weighs in @ 530gr and 3900g thrust, the FMS weighs in at 560gr (the heaviest) 4000g thrust and the Taft weighs in at 430gr and 4400g thrust. On paper the Taft is the way to go. Lighter and more thrust and way less expensive.(but only 11 blade vs 12 blade) So please add some confusion to my decision and pipe in on the pro's and cons for each. Thx.....

WOW, interesting choices. The FW is only my favorite because I haven't tried the FMS or Taft Hobby and I replaced much less powerful EDF's with the FW, so the difference was off the charts. But for the price (1/2 FW), the weight (100 g less) and the thrust (10% more), not sure you could do anything but try the Taft Hobby EDF. Interesting that it weighs so much less than the other 2. I kinda stuck with FW because I'm comfortable with their product and know their customer service-sometimes it's tough to teach old dogs new tricks!

[The43rdHammer]

I don't know how it compares, but I had a Taft Hobby 90mm Cobra a few years ago (maybe 2018) .... I wasn't impressed and sold it on . Wouldn't buy another one and the stock power setup was 💩

https://www.rc-castle.com/index.php?route=product/product&product_id=5966

[Mizer67]

So after seeing much debate on power for the F-18 ( 9 Blade vs 12 Blade) I have decided to upgrade the Blue to 12 blade. Question is which one. Here are the choices: Freewing 90mm 12 Blade 4068-1835kv @ $158. ( Hugh Wiedman's favorite 90mm) the FMS 90mm 12 Blade 4068-1850kv @ $116. or just for interest the Taft Hobby 11 Blade 3674-1500kv @ $73. The Freewing weighs in @ 530gr and 3900g thrust, the FMS weighs in at 560gr (the heaviest) 4000g thrust and the Taft weighs in at 430gr and 4400g thrust. On paper the Taft is the way to go. Lighter and more thrust and way less expensive.(but only 11 blade vs 12 blade) So please add some confusion to my decision and pipe in on the pro's and cons for each. Thx.....

The FMS and FW are essentially identical in terms of output in my testing. Within ~3-4%, with the thrust, price, weight, speed and efficiency nod(s) going to FMS. That being said it does take a bit of carving to make the FMS fit, whereas the FW is a drop in replacement.

If you don't mind the extra 30 min. of work the 1850kv 6S FMS unit would be my pick, but at the same price (and they're typically much closer in price between one another if sourced from China direct), it's essentially close enough to be a non-factor and I'd defy anyone to identify the fan that was in the plane by how it flew alone.

As it stands, assuming that is the pricing you have, the less expensive FMS unit seems like a no-brainer to me. I hate carving foam, but the pricing delta is significant enough that I'd take the plunge as $158 stings just that much more to me.

I have no experience with Taft, but good experience with FMS and FW, so I'd pick one of those two.