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Old Jun 16, 2012, 07:39 AM
pavcon is offline
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Originally Posted by Banjofrog View Post
Hey Pav welcome aboard, how is your Vampire going? great I hope like mine

Shaun.
Sold it.
The vampire rocks. I only sold it because the guy who wanted it suffered an eye injury and he only flies small planes.
I also wanted the extra cash to build my latest buy. The hK l-59.
I will buy it again. I've got everything I need to build another kit. But Danny. That thing with the Schulman fury fan sounded great.
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Old Jun 16, 2012, 08:20 AM
ozzi supercub is offline
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Originally Posted by phoenix racing View Post
Very simple, as I said in the video.....I didn't like 4s....it upset the balance of the airframe. The Zephyr responds well to small changes in C of G, it's all about flying styles, if you are simply looking for speed......maybe 4s, however, the airframe is very slippery compared to the usual EDF jet...hence it requires relatively little power to achive good speed, but the larger 4s pack counters that speed by reducing the vertical performance and certainly hurting the aerobatic performance (look at pack weights, a 3300mAh 4s is very heavy compared to the only 4000mAh pack we reccomended for it, which is the Zippy Compact).......put simply, 3s gave the best overall balance as I said in the video, of speed/aerobatics/flight time, this is a model that will be flown in many different ways, which is exactly what we wanted to achieve, owners will need to fly it most likely before they really understand what I am talking about, it is very responsive to changes, allowing the pilot to get exactly what they want from it...if we went 4s....all that would be gone....the flight envelope would be reduced and so would the V70's appeal.
I guess seeing as your the only one who's flown it you would definitely be on the money.
It will be interesting to see which direction new owners go with this model. I'm guessing there will be quite a few who just want a crazy fast V70 for low passes. Maybe a good candidate for a speed comp Scott
Old Jun 16, 2012, 08:30 AM
karoliinasalmin is offline
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Originally Posted by ozzi supercub View Post
My personal opinion is that all things being equal, by that I mean battery, fan, motor etc etc the Zephyr will be faster.
If wing area is equal and wetted area is equal and weight is equal, then:
Sailplane shape is better at low reynolds number than a delta/jet shape what it comes to drag because this (jet) shape is designed to minimize supersonic drag. At slow speeds supersonic jet shape scaled down to RC has nothing to do with the speed, it is for looks and images to people that think it must be fast because it looks like that. Low aspect ratio can be a design parameter in rc planes for resistance to wind and turbulence.

Rule of thumb for low drag is that it is better to increase velocity of large air mass a little than increasing the velocity of a small air mass a lot. The velocity increase is needed to produce lift and a long slender wing does that with less drag. Pod shaped fuselage with fineness ratio 3.33-4 is optimal and that is why all sailplanes have pod+boom. The boom makes it worse than the pod would be alone, but the tail must be moved aft enough to have enough elevator authority without overly large tail which would also increase drag. To go fast there are two options, use a lots of more power or have less drag. Reducing drag is easier and better as lots of power in a very small plane can be very difficult to obtain except with a real jet engine.

The sailplane shape is good all the way to the edge of transsonic region and nobody's rc jet is even near that.
Old Jun 16, 2012, 08:53 AM
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Picked example video from Youtube that shows how fast a "glider" goes:
http://youtu.be/LE3gYPPL8kc?hd=1
The flight is on the second half of the video.
Old Jun 16, 2012, 09:46 AM
Banjofrog is offline
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Geez That's A Big Fly
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did you see that, see what I only heard it, oh I saw the hand launch and landing geez that is quick

Shaun.
Old Jun 16, 2012, 10:45 AM
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Hey, the Vampire and X8 people are migrating over here.

I figure, you only live once, so I just kept clicking till the thing was ordered. Everything about the V70 just "felt" right. I was going to order the Me-163 as well, but after looking at the Komet thread and looking at the vids, it didn't "feel" right - just a bit too goofy and under-designed.
I think I'll go by what Scot (? Phoenix) has found and just fly it stock. I was just trying to economize on batteries. I'm not after speed but more for the look and sound of a sleek, EDF sailplane. Oh, and I love V-tails.
I have the Scimitar and it's just a bit on the "too fast" side for me right now. I rarely fly that thing at full zoot - too scary. As for speed, my Funjet Ultra with the regular Funjet powertrain is just about right.
Although the V70 will be my fastest sailplane, I don't necessarily need it to be my fastest plane.
Old Jun 16, 2012, 05:26 PM
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The Earth got in the way!
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First let me say I like the Zephyr a LOT but, I'm still on the fence until we see so real video. I've owned a LOT of EDFs and honestly none on 3s would hit these speeds....only on 4s. 3s 70mm with a 3400kv motor I just don't see it. I have to assume that some of if not most of the speed has come from putting it into some sort of a dive then going level then since its so slippery carrying the speed through vertical. Just my personal experience flying a lot of EDFs.
I even modded a 64mm Maxjet F-18 to run a 70mm 3000kv on 4s 2650 40c's and it had no where near the performance that this video shows. My last Habu on 5s didn't either. The only thing close was my Evader on 4s with a Wicked 4000+.
I know it's slippery but, 70mm on 3s with that performance.........I hope so but, I just have to "really" see it to believe it.
Last edited by kuczy; Jun 16, 2012 at 05:31 PM.
Old Jun 16, 2012, 05:29 PM
Snoggle is offline
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same here... waiting for reviews from you guys who actually bought the plane and videos of course... but its always hard to guess/feel the actual speed of a plane just from videos, no matter if they are edited or not. better see or even better fly it yourself in reality...
Old Jun 16, 2012, 05:57 PM
ozzi supercub is offline
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Your dead on there kuczy. Im guessing this thing will have plenty of static thrust but the efflux will be quite low. To get high performance from an EDF you need to spin them smoothly at insane RPM. Time will tell.
Old Jun 16, 2012, 09:06 PM
Scott Cuppello is offline
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lol....the video is real.....speed is lack of drag....but it seems there is not much point explaining it again! You will understand this when you shut the throttle and the V-70 hardly slows on a pass...speed is from the airframe, not the fan..... take the fan out of the equation and substitute for prop drive and you probably wouldn't question it........but by all means, wait for the reviews.
Old Jun 16, 2012, 09:31 PM
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WAA-08 THANK FRANK!
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It is human nature to reinvent the wheel (wing?)
Old Jun 16, 2012, 09:48 PM
kuczy is offline
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My Evader had little drag and would carry speed well...on 4s with a 4000kv motor. Lack of drag isn't going to over come a lack of thrust. Well see when a real video comes out. As I said I really hope it does preform like the video because I'll order one.
Old Jun 16, 2012, 10:06 PM
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Scott you have to understand that because this model is so different to anything available currently, questions will be raised. I'm guessing most guys here when they see a new model start thinking about how to mod it to try and improve it. Sometimes it works and sometimes it doesnt. EDF guys are the worst of the lot Its always 4S, 5S, bigger lipos, more speed lol
It only seems fair that if your prepared to accept people singing its praises before they've even flown one or even seen one fly then you should also be prepared to accept people asking legitimate questions.
We were discussing the Zephyr at my field this morning and I was wondering how the V-tail and the servos would handle being blasted by a 200+ kmh wind blast from a hot EDF system. I guess we'll find out when the the next batch arrives
Old Jun 16, 2012, 10:12 PM
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The battery/ESC/receiver compartment looks like its going to be a tight fit with big 3300-4000 packs. I noticed two cooling intakes on the nose, but I did not see any cooling exhaust. Maybe there is an exhaust hole just in front of the fan, but again, did not see one because there was no picture at that angle. A 4S pack may produce too much heat. Does anyone know if this plane has cooling exhaust?
Old Jun 16, 2012, 10:22 PM
Scott Cuppello is offline
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There is an exhaust hole at the rear of the battery compartment.


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