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-   -   First EDF - any tips (http://www.Wattflyer.com/forums/showthread.php?t=73546)

Zacs 04-11-2014 01:19 PM

First EDF - any tips
 
My son has just bought a Hobby King Jet Tiger (tiger jet?)

This will be his first EDF. He has a couple of flying wings and varous electtric planes which he flies well (he's 18)

Any advice on what not to do with the edf (apart from the obvious!)

dahawk 04-11-2014 03:22 PM

Hi Zacs,

Welcome to WF. can you tell us a little more about this model? Fan size? Wing span? Does it have a rudder? Hand launched or rog ? 3S, 4S, more?

This one? http://www.hobbyking.com/hobbyking/s...arehouse_.html

18? Video gamer ? This will be a cake walk for him.

I have a squadron of edf's ranging from the small 50mm's to 64mm's to 70mm's . All have their unique character in terms of flyability.

As this is the first go in the category and he's already experienced with flying wings, etc. there should be nothing to fear.

A couple of things to check: 1). CG- very important that these planes are balanced properly. Find a thread somewhere on the particular model. Check RCG. Often times the mfg.'s recommended cg is off ( by a lot). 2). fan balancing- Many come with poorly balanced fans. Not good. If you know someone who has a dynamic balancer, great. If not, there are several you tubes to show you how to balance edf fans. A well balanced fan makes a world of difference 3). Make sure the blades are not rubbing against the shroud. Not good. Sometimes it take a little light sanding to gain the blade clearance.

On average, expect about 4 minutes of flight time. Most edf pilots fly them wide open. After all, that's why we buy them right? Most will stall rather easily, especially when not enough power is applied through the turns.

Main thing? Have fun !

-Hawk

Zacs 04-11-2014 03:39 PM

Hey Hawk,
Thanks for the encouragement :)

I think we're going flying this weekend so I could post an update on Monday.

The best bit about RC planes htat I have found is the folks who fly them!

Zacs

dahawk 04-11-2014 04:11 PM

Zacs,


More than welcome. Glad to help.


One other thing I failed to mention. If you have a computer radio and I assume you do, you're gonna want to setup dual rates. Hi and low. I take off on high , switch to low and land on high. But that's just me. Check the throws for each rate.

You're also gonna want to include plenty of expo. on edf's I use about 50% for aileron and elevator. I assume this plane is using an elevon mix ?

Lower rates and more expo will help with the twitchiness these bird can display. At least as you're getting used to it.

Good luck on the maiden. Get some vid !

-Hawk

xmech2k 04-11-2014 04:14 PM

Don't crash! :D I think if he's doing flying wings he'll be fine. But good tips, Hawk.

fhhuber 04-11-2014 04:15 PM

Keep the airspeed up.

Keep the turns wide. A tight turn will bleed off speed and the EDF will not hold your airspeed like a prop driven airplane.

EDFs are not good at producing static thrust. They are OK for pushing an airplane at speed.

In some cases you have to chop throttle to recover from a stall.

Zacs 04-11-2014 04:21 PM

Hawk,

I will let you know how we get on maybe even some vids :-)

He's just trying to work out what he can safely get into a suitcase when we go to FlightFest in Ohio in July. Probably just a wing :-(

Take care

Zacs

dahawk 04-11-2014 06:55 PM

Cool ! Going to meet Josh and Josh? I built the FT 70mm Saab Viggen kit. Easy build, flies nice but not a speed demon. Hey, for $39.00 ?

Fishbonez 04-12-2014 01:27 AM

Great advice. Hawk. The only advice I have and it already has been given keep your speed up and have a blast. Oh also I would add this. I have a tradition on every maiden flight. Prior to taking off I always take a picture. I always say that it may never look this good again I state my pucker factor based on 1-10 one being the least puckered. I am usually at a 12 on a maiden. Then I go for it. Since I have done that in that order I have always had a successful maiden. Just my .02 worth

thepiper92 04-12-2014 01:32 AM

Lol, you just know something is gonna go wrong don't you? I try to be optimistic: "I ain't taking no pics, it's always gonna look this good!" Plus my iPod isn't great for pictures.

Fishbonez 04-12-2014 05:01 AM

Quote:

Originally Posted by thepiper92 (Post 945219)
Lol, you just know something is gonna go wrong don't you? I try to be optimistic: "I ain't taking no pics, it's always gonna look this good!" Plus my iPod isn't great for pictures.

Oh I am always optimistic but I am a realist and like any baseball player superstitious maybe...:D

thepiper92 04-12-2014 05:03 AM

Quote:

Originally Posted by Fishbonez (Post 945229)
Oh I am always optimistic but I am a realist and like any baseball player superstitious maybe...:D

Think you gotta spit on the prop before you fly, just like in baseball.

Fishbonez 04-12-2014 05:08 AM

Quote:

Originally Posted by thepiper92 (Post 945230)
Think you gotta spit on the prop before you fly, just like in baseball.

Hmm you might be on to something there a little spit and maybe even a little ceremonial dance to the RC Gawds

thepiper92 04-12-2014 05:10 AM

The RC Games: May the odds forever be in your favour...and the trees not suddenly appear when you are landing, or a huge gust of wind, or the sun blinding you, making you lose sight of the plane...and so on.

solentlife 04-12-2014 06:41 AM

My maidens always have my 3 kisses to the gods with Please Please Please.....

My flying pals all chuckle at it... but Ive always done it since starting out in models over 50yrs ago.

Nigel

dahawk 04-12-2014 03:43 PM

I've managed to piss-off the gods on occasion and paid for it dearly. I think I'll try the 3 kiss approach next time.

thepiper92 04-12-2014 06:44 PM

Think ill have to build a ritual circle and provide an offering before my p47 goes for its maiden. The gods are already angry, it's snowing again here.

satnaam 04-16-2014 02:38 AM

I setup mine with 4S
 
Flys ok, but not fast. Gave it to friend as I did not like it.
satnaam:sad:

fhhuber 04-16-2014 03:09 AM

Now we get into the issues with foam RTF/RX-ready EDF models...

Often its something really simple to improve performance. Most of the time its just inadequate air intake.

xmech2k 04-16-2014 06:49 AM

Quote:

Originally Posted by satnaam (Post 945553)
Flys ok, but not fast. Gave it to friend as I did not like it.
satnaam:sad:

Flew what one time? Are you the son of the OP? Most ARF edf's are snails out of the box. They need some help to fly like a jet!
edit:never mind. I didn't read the beginning of your post in the title. I never read those usually.

satnaam 04-17-2014 02:59 AM

I flew it on 4S
 
With a 2w 20 het motor on a 64mm fan. The airframe was too draggy and no speed. That's what I meant.
Satnaam

solentlife 04-17-2014 07:05 AM

Quote:

Originally Posted by fhhuber (Post 945558)
Now we get into the issues with foam RTF/RX-ready EDF models...

Often its something really simple to improve performance. Most of the time its just inadequate air intake.

mmmm most I see ... inadequate performance is due to the Factory recc'd LiPo being too small and unable to deliver what motor really wants.

50mm Skyangels are good example .. the 800 3S 20C is a joke. Swap to a 1500 3S 25C pack and you get a good jump in performance. ie my T45 went from 280gr thrust on 800 to 340gr on 1300 LiPo ... same intakes, motor, fan and ESC. On 4S 1600 she jumped to over 450gr ...

Nigel

dahawk 04-17-2014 03:10 PM

+1 on both comments. Air intake and lipo power. Also , on air intake, consider turbulent air flow versus laminar flow going in. If you have a bunch of obstructions in front of the fan disrupting intake , you'll lose some efficiency. The air in front of the fan is called the Fan Swept Area (FSA). An inlet lip on the front of the fan also helps with the intake airflow.

And on the exit side, having the proper exhaust tube dia. for optimal efflux speed can make a big improvement. As a rule, you can never fly faster than the efflux velocity.

On most of these foam molded planes, there's not much one can do to enlarge the tube but for the tubes that are too big, it's easy to apply a tube to make it smaller.

waytooslow 04-17-2014 03:33 PM

Here is how I fly mine.

FULL THROTTLE...... if it explodes -- a bonus. but seriously.

Airframe does have a lot of impact on speeds, eventually all the power in the world will not overcome poor aerodynamics.

fhhuber 04-17-2014 05:08 PM

A very good example of inadequate intake is the Art Tech F-18.
Increase the size of the cheater holes double front to rear and TRIPLE wide. cutting the foam at an angle to avoid restricting flow to the fan.
It goes from being a dog that can barely take off and fly level into being easily capable of looping from level flight and able to hold double the speed vs OEM. Then put in a better quality battery...
Earlier version had the battery in front of the nosewheel and half the capacity of current version. I wrote a review explaining putting a double capacity battery behind the nose-wheel and getting a large performance improvement despite the added weight and next thing I see is they made the change standard (but still with a low quality LiPo, labeled 20C but actually performs like a 6C pack) They didn't change the cheater holes as that would mean new molds.


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