Ranger_107
Elite member
hehehe. My dad ordered an esc for a 70mm edf 2 months ago and we are still waitingme too!"!!The ESC is here at monday latest, and then ill try do last checkups, even if not got all retracts till then.
Piper Jet (PA47)
- Thread starter leaded50
- Start date
leaded50
Legendary member
Ive ordered a few last 6 mnthsfrom Asia.. and must say, they are shipped (the ones who have come) by bicycle or somehing
leaded50
Legendary member
Your in Norway too? and what size ESC do you need?
Earthchill
Member
I'm in Sweden. I was looking at building a FT Viggen. With a FMS 70 mm EDF I would need a 70 A ESC. The price difference between HobbyKing and rcflight.se was 48€ (19€ vs 699 SEK). The shipping time also differs a lot. I suspect the quality differs as well. The question is if I need the quality of the HobbyWing ESC (and if the quality difference warrant the price)?
I then saw Tom Stanton's video with a 70% FT Viggen. That can use a 50 mm EDF and then the prices gets to a more manageable level. After all I really want the "local" stores (i.e. next day delivery and Swedish consumer laws) to survive and I'm happy to pay a premium for that.
jfaleo1
Junior Member
I really like where this is going, So I am going to give you some info I have on this aircraft I go from a Mechanic who was working for the company during the development of this aircraft. Take it for what i is worth.
This airplane has a very pronounced pitch change with the throttle, high power noses down, which required pitch coupling to the throttle. This should not be a surprise considering engine location, but this may be some needed info for you, be ready, i really want to see this succeed! Not a Piper fan (J-3 is the exception) but I LOVE weird and rare airplanes, this is both.
Luck,
leaded50
Legendary member
699 SEK was high.... i byed mine 80A for approx 380 SEK. (but thats not normal pricetag) mainly i like the Red Bricks buyed eg from Ebay. Just rememeber some (opto??) is some version without BEC, some with.
In my opninon, a 50mm EDF is not perfect for even a 70% Viggen, they mostly have a thrust of 650 - 750g max. theoretically, and also thrust on a EDF isnt as on a propeller at the startmoment. When plane got up in speed yes, ok. Started by a "slingshot" is nice! At a prop plane they say it can be approx 30-40% less thrust in g than the plane is weighting... at EDF it need easy be 30-40% lighter than the thrust of the EDF, if not a wide wingspan glider.
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leaded50
Legendary member
I read about it @jfaleo1 Also that later model (Altaire ) they did made automatic adjustment system to counteract it. Im not sure, but tryed to think about it, when i setup the wing incident, and edf thrust angle. Motor is placed higher than the fuselage, so such motion is "normal" Thats also reason thrustangle isnt always 90 degree on with a prop plane with high mount either, special if pusher or on front of tailfin.
I did make a EDF test today, with connect it to another plane just to see how function, and its rare see a minor "twist-reaction" on the tailfin on a plane by full speed up. Its buildt sturdy enough, so not afraid it breaks eg... just a rare minor motion
Also that later model (Altaire ) they did made automatic adjustment system to counteract it. Im not sure, but tryed to think about it, when i setup the wing incident, and edf thrust angle. Motor is placed higher than the fuselage, so such motion is "normal" Thats also reason thrustangle isnt always 90 degree on with a prop plane with high mount either, special if pusher or on front of tailfin. I did make a EDF test today, with connect it to another plane just to see how function, and its rare see a minor "twist-reaction" on the tailfin on a plane
by full speed up. Its buildt sturdy enough, so not afraid it breaks eg... just a rare minor motion
jfaleo1
Junior Member
I read about it @jfaleo1
I did make a EDF test today, with connect it to another plane just to see how function, and its rare see a minor "twist-reaction" on the tailfin on a plane
I am very glad you saw all of this already since I came to this so late. Just for fun.....You are very right about incidence on propeller aircraft but, jets do it too. On the airplane I teach maintenance on one of the changes that was done between the Citation X and the X+ was the angle of the engines relative to centerline in both the vertical and horizontal planes. This was due to changes in the amount of thrust and the length of the airplane. Done with fun and useless knowledge transfer now.
leaded50
Legendary member
I am very glad you saw all of this already since I came to this so late. Just for fun.....You are very right about incidence on propeller aircraft but, jets do it too. On the airplane I teach maintenance on one of the changes that was done between the Citation X and the X+ was the angle of the engines relative to centerline in both the vertical and horizontal planes. This was due to changes in the amount of thrust and the length of the airplane. Done with fun and useless knowledge transfer now.
Nice to hear from someone knowing the build of the plane anyway
I hope i got it right n angles, if not, at least i will find out
When scratchbuilding without any "controlled" plan, but bad drawed 3D drawings or/ an papermodel plan... all you can do is try after what you believe is right, after what you learned by experience and found by info. I liked the idea of the plane design, and it did fit my wishes
leaded50
Legendary member
on of reasons for its rare with just a single jetmotor on such planes are FAA rules, and of course as earlier noted, the pitch reaction.
On many of the "tri - jetmotor" planes the middle motor have a S duct to set the exhale of powerthrust more to the centerline of a plane, even if centermotor relatively is as high as on the PiperJet..
But i had one EDF to use, not two ha,ha, and no gain, no pain? Most of a "scalestyled" RC is an experimental aircraft anyway.
On many of the "tri - jetmotor" planes the middle motor have a S duct to set the exhale of powerthrust more to the centerline of a plane, even if centermotor relatively is as high as on the PiperJet..
But i had one EDF to use, not two
ha,ha, and no gain, no pain? Most of a "scalestyled" RC is an experimental aircraft anyway.
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Earthchill
Member
I wouldn't have thought about it if it wasn't for this video. I can't find the test video on RCGroups but it seems like the 4S 50 mm FMS produces the 850 g of thrust that the manufacturer promises (a bit less in an airplane though of course). Assuming that the foam board scales with 0.7 squared (since the thickness and paper doesn't change) the total weight should be between 450 and 500 g for the 70 % Viggen including a 4S 1.8 Ah battery.
I won't derail this thread more
. Will create my own build thread once I start building.
leaded50
Legendary member
@Earthchill , FMS KV4500 11bladeds on 4S is said to be 850g thrust yes .That plane weighted 255g without only battery , edf approx 75 .. 180 grams plane weight, minus servos/esc/reciver.. You need build light, very light. He also mentioned ist discussable that 50mm fits the model..but it did fly though
My Ikarus weights 410g without battery, and with a EDF 4600kv 12 blade, with given thrust of 780g, 403W, and i got problem get it launching, sometimes get , sometimes not.
My Ikarus weights 410g without battery, and with a EDF 4600kv 12 blade, with given thrust of 780g, 403W, and i got problem get it launching, sometimes get , sometimes not.
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Ranger_107
Elite member
Is there a maiden video?
leaded50
Legendary member
should have been. Still awaiting for a few cables in mail, so can complete its functions.
Ranger_107
Elite member
leaded50
Legendary member
Quite normal you need solder on batteryplug and female bullet plugs.
Be sure your EDF dont max out over 55-60A.
Ranger_107
Elite member
huh? max out? the motor needs at least a 45 amp but 60 is all we could get.
will the edf break if we have too big of an esc?
leaded50
Legendary member
if the EDF draw more than 60A max, yes, you will get a "smoke-out" esc get to hot, and destroy it self. To big ESC dont matter.
Specs on tjhe specific EDF says what max Amp is.
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whackflyer
Master member
60a will be fine if your EDF only pulls 45a max. It's good to have some extra head room. You probably could even run a motor on it that pulled 55 or 60 and you'd be fine.
