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Old Nov 13, 2010, 10:24 AM
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Originally Posted by Ispintechno View Post
So, I've put some thought into my first EDF, the nitroplanes 70mm F4 Phantom. I picked 70mm over 64mm because they seem floatier and less twitchy. Bigger is better, easier to see, better wing loading. Earlier in the thread it was said by our panel of experts that the F4 is a bad choice, and I disagree. Although I have seen videos of the smaller exceed version and yes, that one looks very hard to fly. Actually terrible on all fronts. So maybe that was it?
The F4 has large delta style wings, I hear the 70mm is very light and big. Sounds floaty to me. I thought I was being clever with this one, the fans blow under the elevator, maybe making stall recovery a little easier, at least with pitch.
So it's an airframe only, I'll be putting in quality servos and RX. A cheap yet powerful hobbyking motor and turnigy plush 60amp ESC. I'm fairly confident I'll bring it back in one piece if the power system quits so long as my RX and servos are functioning correctly.

So currently I fly foamy warbirds. I fly the parkzone corsair very well fast or slow (plus a couple other foamy 4-channels). I can do inverted, hammerhead stalls, all the usual immelmans, cubans, short distance knife edges (I think its the gull wings making them short) etc.
Before the corsair I actually was flying a parkzone Slo-V and transferred just fine to the corsair right away (thanks to my sim I'm sure) so I don't really think taking the plunge to an EDF is quite as big a deal as it's made out to be... yes I agree it will be different.
I guess we'll have to see if I walk the walk, but I'm optimistic about the upcoming adventure. Guess I'll report back later once it happens! (the F4 is a Xmas present, have to wait)
Very bad choice in my opinion. My first EDF was an F-4, no power, and having the thrust "under" the elevator doesn't help at all. It's an unstable, fast airplane for starters, no matter how you look at it, it's just not designed to be easy to fly. The full scale was supper twitchy at speeds, as was mine i found, and had not enough twitchyness when landing. It doesn't have delta style wings, they are trianglular but still has a horizontal stab so slow speed is not a good flight regime like a standard delta. The bigger is better thing is a matter of opinion, they are easier to see, though hurt more when something bad happens, as for being floatier, that depends, i usually just figure the weight and wing area grow linearly so it doesn't make any difference. Your power to weight with a 70 over 64 is probably better, but it depends on your fan. I would go with something like an F4D-1 Skyray, jet, but has a LOT better tendencies, great slow flight, and get zoom pretty well.
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Old Nov 13, 2010, 10:47 AM
Defender of the park sky
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London, ON Canada
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Thanks snivilous for the reply. Man, everyone made this F4 look pretty easy to fly... lol Almost Habu easy. (to be honest, I'm not looking for the easiest airframe to fly, I like my favourite scale planes. I'll do easy patterns up high to get used to it)
Tony from NP described it as a relaxed flyer in comparison to the Airfield F-16.
Well I'll make sure I give it enough power, a little extra on tap is good to get out of a sticky situation. I've been reading threads here with interest in the power systems people are using on similar sized airframes.
Also, I really like the new NP MiG-15 70mm, maybe I'll build the F-4 with a pretty hot set-up, and try flying a RTF MiG-15 70mm first? Even thinking about holding off on the new P-47 just to get this right.
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Old Nov 13, 2010, 01:42 PM
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Quote:
Originally Posted by Ispintechno View Post
Thanks snivilous for the reply. Man, everyone made this F4 look pretty easy to fly... lol Almost Habu easy. (to be honest, I'm not looking for the easiest airframe to fly, I like my favourite scale planes. I'll do easy patterns up high to get used to it)
Tony from NP described it as a relaxed flyer in comparison to the Airfield F-16.
Well I'll make sure I give it enough power, a little extra on tap is good to get out of a sticky situation. I've been reading threads here with interest in the power systems people are using on similar sized airframes.
Also, I really like the new NP MiG-15 70mm, maybe I'll build the F-4 with a pretty hot set-up, and try flying a RTF MiG-15 70mm first? Even thinking about holding off on the new P-47 just to get this right.
I agree, easy flying airframes can get boring My F-4 was from a couple years back, so recent brushless systems are a lot better than that one had. It may fly fine, it's just my 64mm F-4 was horrible, but that may have been just me or a poorly designed airframe. Good luck with it though!
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Old Nov 13, 2010, 01:55 PM
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Quote:
Originally Posted by snivilous View Post
I agree, easy flying airframes can get boring My F-4 was from a couple years back, so recent brushless systems are a lot better than that one had. It may fly fine, it's just my 64mm F-4 was horrible, but that may have been just me or a poorly designed airframe. Good luck with it though!
I think this is a very different animal than 64mm, which if it is the one I've seen video and comments on, yes very hard to fly. But I think you could very well be right on the money with inherent stability problems of the F-4 phantom. The real plane had issues, hence why the wingtips curve up and the elevators go down. All corrective for flight characteristics.
We'll have to see if the "fly-by-inspintechno" flight system is up to the task!
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Old Nov 13, 2010, 02:15 PM
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Quote:
Originally Posted by Ispintechno View Post
I think this is a very different animal than 64mm, which if it is the one I've seen video and comments on, yes very hard to fly. But I think you could very well be right on the money with inherent stability problems of the F-4 phantom. The real plane had issues, hence why the wingtips curve up and the elevators go down. All corrective for flight characteristics.
We'll have to see if the "fly-by-inspintechno" flight system is up to the task!
lol, you need to tell me about it when it gets in the air. since the first F-4 was such a failure, i stay away from them, even though it's probably the 2nd or 3rd most modeled edf after the F-16. If yours goes well I might try again
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Old Nov 13, 2010, 03:13 PM
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@Ispintechno; EDF is easier if you've flown something. It directed more to some who try these as their first models with little experience.

Don't mix up an unstable airframe with a limited control envelope. Very few models are designed as unstable airframes. The CG is way forward of the Scale CoL. The wing foils are seldom to scale.
On the F-4 model the flaps are being used as the ailerons since I've never seen a version with the wing tip surfaces active. Most us a Stab/Elevator instead of stabilator. And the rudder is still small and the wing load is higher than on most models; very different than a park flier. This all means you are closer to departure than with other models. If you are new a stall can creep up on you fairly quickly.

Comparing the F-4 to say an F35 or F22 with greater wing area and largers flight surfaces, your learning curve is easier while you maneuverability is much better.

It just means you have to fly a tighter limited pattern, maintaining speed, with the F-4 and if you do something outside of that limit its harder to recover. It doesn't mean its unflyable. If you're set on the F-4 have fun.
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Old Nov 15, 2010, 09:57 PM
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United States, TX, Burkburnett
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my first edf was the f4 64mm flies nice . try flying on aday with 5 to 10 mph makes landing easier . my first time i tried gliding it in . i bounced down the runway . 2nd try pitched the nose up just a little and alittle throtle to controle sink rate .
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Old Nov 15, 2010, 10:34 PM
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United States, TX, Burkburnett
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just saw anew edf might be a good 1rst one . nitroplanes under ready to fly planes . its not under edf jets. twin corperate jet like a citation looks nice
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Old Nov 16, 2010, 12:46 PM
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dubai
Joined Oct 2010
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hay
if u remember me i'm the new guy for the f-14 i decide to buy another plane as trainer plane and i went to the shop and i asked for a trainer plane and he gives me the extra 300 so i went to friend and i told him i got a trainer plane and when he saw it he laugh a lot an he said that not atrainer at all so i got upset and i told him noway . i will fly it so he helped me in the first 2 flight and i toke the radio from him and now i did 12 flight with out any crach so now i intend to fly my f-14 next week so i can fly it ??!!!!
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Old Nov 16, 2010, 01:35 PM
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Why not! If you can handle the Extra 300 I think you have a chance to fly the Tomcat!
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Old Nov 16, 2010, 02:05 PM
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Good for you. I don't know which 300 you have but now add dead weight to make it harder to fly and dead stick it in for comparison. For the F14 Just remember, there is now no prop wash, keep your speed up, the landing gear is much more sensitive to hard landings.

Congrats and have fun!
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Old Nov 22, 2010, 03:23 AM
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dubai
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guys i hope u can help me on that .
i flew the f14 finally but i feel its under power so i intend in the future if its still alive i want to upgrade it so can i use higher kv engine or bigger battery ?? and what is the relation between the kv and the power ?
i got this equations form one threat here so i did simple calculations and i found that :-
RPM = Kv * voltage
torque = Kt * current
Kt * Kv = 1 (IN THE MKS SYSTEM) or some crazy constant in other systems.
power = torque * RPM = volts * current (with some constants to fix units of measure)
so i found the engine which have 2315 kv with 1 amp current and 11.1v gives u .000043 of torque and 11.1 of power
and the engine which have 5000kv with 2.2 amp current and 11.1 v gives u almost the same torque (.000044) but gives 24.4 power
so thats right or wrong? and any new idea???
thanks
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Old Nov 22, 2010, 10:12 AM
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I can only help so much because I've yet to build my first edf. But that Art-tech Tomcat looks severly underpowered. You're going to have to go with new twin 55mm edf set-up unless you hog out the foam (it there is enough) to up size it. Also I would look at 4S set-up and abandon the 3S set-up it comes with. Typically from what I'm looking at, the smaller the edf the higher the KV. I imagine 55mm edfs would run at over 4000kv.
Maybe new motors and speed controller would be the place to start if the stock fan is up to the task.
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Old Nov 22, 2010, 04:45 PM
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Weight is your biggest concern. If the wing load is high, steep glide ratio, you have limits.
Batteries with higher C count can help.
Performance look to increasing the volts first if you can find a motor that can handle the extra 3.7V. The increased voltage can mean you can decrease the size of your ESC decreasing the weight. The increase in volts also means you can get smaller mAh batteries.
The flip to this is higher KV motors get hot, draw more amps and battery wire length becomes more critical.
Do a general search in RCG for 55mm motors. See what configs work for people.
The smallest I have is 64mm so can't point you to anything from personal experience.
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Old Nov 22, 2010, 06:58 PM
James L
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Beck Row Mildenhall
Joined Mar 2009
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Maxthrottle if the kV of the moter stays the same and you add 3.7 volts the fan will spin faster and the amperage will go up, not down. You will need a bigger ESC if you are marginal at the moment.

If you reduce the motor kV, to get to the same rpm as the original set up achieved, but with the additional voltage then the amperage will go down but then the performance will not alter very much. Although there maybe a slight reduction in wing loading but I think that would be marginal as a bit of extra endurance is alluring so most of us do not reduce the battery capacity any more than is required to get back to the original pack's weight.

Could be of course that I have missed your point?
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