EDF Help

[TomcatFLYER]

Hi, I'm building an F-14 tomcat model from EPF.

I need some help and advice on the chioce of electric powerplants to use.

Should i use what they recommend on the site?

Or

The typhoon and wemotec 480 combination?

I'm kinda new to edf systems... so i need some advice

i'm looking for speed and power for my model.

thankz

[TomcatFLYER]

their site is www.rc-epf.com

[Ryan]

looks good. hows the model quality and are you using retracts?

pics please

[flying bear]

hi tom,

u may want to PM freeman, he is building everything as per what was recommended.

bear

[Warbird]

Hi TomcatFLYER,

As the EPF Tomcat uses a 70mm fan you should have no trouble using either a WeMoTec Mini Fan 480 or a HET-6904 Fan.
Combined with a Typhoon 2W at 3S or a Typhoon 3W at 4S this will give you close to 1000 Watt combined power. Unlimited verticals shouldn't be a problem as the planes fuselage should be very light.

Only a few concerns:

1. The Motors together with the fan will create a much higher airflow then stock fan so you have to make sure that your intake ducting will not collapse due to the low pressure area created by the airflow (I have not yet had a look at the F-14 construction). As example the early Composite F-16s from HET had problems with a collapsing intake duct when used with a 2W-20 motor (and in some cases even with the 2W and 3W).

2. Batteries required (and ESC). The Motors will draw the following currents at full throttle. As you need 2 of them you need to double the required current draw . You see you need big packs in order to support the 2W and 2W-20 motors. A good option would be a 3W on 4S or even a 4W on 5S. Measure the plane first to see if you have enough space in the fuselage (also considering the CG) before you decide to upgrade.

Typhoon 2W with 3S Lipo: 60A each
Typhoon 3W with 4S Lipo: 36A each
Typhoon 4W with 5S LiPo: 26A each
Typhoon 2W-20 with 4S LiPo: 50A each

cheers,
Eric

[Ryan]

since the airframe is so light. i'd go for the 2w setup with flightpower 3700 3s batts.

2w-20 for something made of foam may be overkill and will kill the wallet too.
trust me. i know this from experience! haha.

get the motors escs fans and batts locally. should be cheaper. and you don't really need to get jeti spin escs IMO. way overkill.

[TomcatFLYER]

i see, thanks.

I haven;t started building the model. Doing my pre-construction plannings now.

I'm aiming for speeds and verticals without compremising the air-frame of my jet.

As i'm kinda new to edf flying, hence i will appear extremely noobish, hope you guys don;t mind.hahahah

I tried emailing the company, as the specs quoted for their set up and Ducted fan only produces a minimal of 480g of thrust per engine. The airframe has a dry weight of 650g and a fully loaded weight og 1.3kg as quoted from the site.

This means i need to achieve a total effective thrust of 1.3kg and above. I'm aiming for 1.6kg thrust. Which i doubt is reachable using the parts manufactured by that company. Any recommened set ups?

So if i were to use the typhoon and wemotec 480's it may cause my intake ducts to collapse? OMG...

i'm so gonna need help

[TomcatFLYER]

sorry for double posting,

Yeha i'm slapping on the new servo-less retracts that the company is releasing soon. IF i can get my hands on it.

[ammo]

Eric(Warbird) will be the guy to talk to for edf planes.

[freeman]

Hi Tomcat flyer,

Regarding the setup of the F-14 which you can get in the LHS, I am using 2 EPF 3900KV motor (Performance equivalent to Mega motor) with stock Ducted Fan. I did not encounter any of the problems mentioned. My setup is a twin 70mm ducted fan, powered by 3S 2200mAH EMAX batt each. Max amp draw is about 33Amp per batt at full throttle.

Having more cells of course will give you more power, but do remember you have to carry more weight too, so you have to strike a balance between power and cell. Tthat is why I opted a 3 cell configuration.

e.g. 1 3200mAH cell weighs about 200g. If the thrust difference generated by 3 Cell and 4 Cell is less than or euqal to 200g, then there is no real advantage of a 4 cell.


You can see the video in a website in one of the LHS. It flown very well in windy condition. For more info, feel free to PM me.

The F-14 will be flown in Singapore in about a few weeks time. The one in the video is build in Taiwan when I was there.

Cheers.

Happy Flying.

[freeman]

sorry for double posting,

Yeha i'm slapping on the new servo-less retracts that the company is releasing soon. IF i can get my hands on it.

Hi Tomcatflyer,

Good news..It will be in soon, maybe you are looking at mid april. How much do you think the system will cost or how much do you think a flyer will be willing to pay? It includes 2 main gear, one nose steering gear and a controller unit that will plug directly into your receiver.
Just doing some study on it...

Cheers.

Happy Flying

[Warbird]

Hi Tomcat,

I had a look at the webpage again. from the pictures it looks like the intake duct is rather solid so you should have no issues when using a WeMoTec or HET6904 Fan.

I would recommend the following setup:

2x HET-6904 Fan (lower priced then the WeMoTec at similar performance)
2x Typhoon 3W or Mega 3 turn motors
2x 40 - 60A ESC
1x UBEC (so you don't need to invest into higher priced ESC's with 4s capable BEC on board)
1x 3000 or better 4S pack (20 or 25C) - will improve the life time of the pack

The 4S pack is recommended in order to give you the best performance out of the 3W motor. Test examples (all in a mini fan 480):

3W @3S: average +/- 200Watt (max 232Watt at the beginning) - 20A max
3W @4S: average + 400Watt (max 471Watt at the beginning) - 31A max

As you can see the output power was doubled by adding 1 additional cell.
4S would be the recommended LiPo configuration for the 3W or Mega 3 Turn.

NOT recommended (the motor is not designed for this much current)
Just another example:
3W @5S: average + 650Watt (max 740Watt at the beginning) - 40A max

Setup summary (based on 3W and 4S setup):

- Combined max Amp draw: 62A
- Combined max Power: 900 Watt
- Thrust (also depending on duct) estimated at ~1.8-2 kg

cheers,
Eric

[TomcatFLYER]

Hi Tomcat flyer,

Regarding the setup of the F-14 which you can get in the LHS, I am using 2 EPF 3900KV motor (Performance equivalent to Mega motor) with stock Ducted Fan. I did not encounter any of the problems mentioned. My setup is a twin 70mm ducted fan, powered by 3S 2200mAH EMAX batt each. Max amp draw is about 33Amp per batt at full throttle.

Having more cells of course will give you more power, but do remember you have to carry more weight too, so you have to strike a balance between power and cell. Tthat is why I opted a 3 cell configuration.

e.g. 1 3200mAH cell weighs about 200g. If the thrust difference generated by 3 Cell and 4 Cell is less than or euqal to 200g, then there is no real advantage of a 4 cell.


You can see the video in a website in one of the LHS. It flown very well in windy condition. For more info, feel free to PM me.

The F-14 will be flown in Singapore in about a few weeks time. The one in the video is build in Taiwan when I was there.

Cheers.

Happy Flying.

Hahaha, actually, thanks to a very observant friend, i manage to obtain the 1st release unpainted series at 99 bucks a piece from aero-smith.

I'll put some pics up later, haven;t started building, cause f-14 tomcats are like my dream planes, wanna make it a perfect jet. Hence alot of palnning now... hahaha, i;m a super noob at e-flying

It has 3 servo wells for retracts

Unlike the real F-14, it uses wing ailerons for rolling. it runs on a servo per side of aileron. I'm kinda confused how to wire it up.

For the stabilators too, it uses 1 servo per side.

No rudders

[TomcatFLYER]

Hi Tomcat,

I had a look at the webpage again. from the pictures it looks like the intake duct is rather solid so you should have no issues when using a WeMoTec or HET6904 Fan.

I would recommend the following setup:

2x HET-6904 Fan (lower priced then the WeMoTec at similar performance)
2x Typhoon 3W or Mega 3 turn motors
2x 40 - 60A ESC
1x UBEC (so you don't need to invest into higher priced ESC's with 4s capable BEC on board)
1x 3000 or better 4S pack (20 or 25C) - will improve the life time of the pack

The 4S pack is recommended in order to give you the best performance out of the 3W motor. Test examples (all in a mini fan 480):

3W @3S: average +/- 200Watt (max 232Watt at the beginning) - 20A max
3W @4S: average + 400Watt (max 471Watt at the beginning) - 31A max

As you can see the output power was doubled by adding 1 additional cell.
4S would be the recommended LiPo configuration for the 3W or Mega 3 Turn.

NOT recommended (the motor is not designed for this much current)
Just another example:
3W @5S: average + 650Watt (max 740Watt at the beginning) - 40A max

Setup summary (based on 3W and 4S setup):

- Combined max Amp draw: 62A
- Combined max Power: 900 Watt
- Thrust (also depending on duct) estimated at ~1.8-2 kg

cheers,
Eric

Whoa, cool... 1.8kg to 2.2kg just what i need, so it should be okay if i run it on your calcualtions above?

I will produce an image of the ducts later for ur closer examination. will reinforcing it with aluminum rings help? Only one battery will do?
hahaha... if possible, can teach me how to calculate all this set up specs?

Thankz

[Warbird]

No problem.
Yes, please post some pictures and I will have a look.

Let's see if the duct can be used as it is. We should avoid adding more weight.