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The ZEPHYR

fliteadmin

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#1


The Durafly Zephyr V-70… yep, we got it! From the super compressed EPO foam body construction, carbon and fiberglass reinforcement to the bi-lateral EDF intakes and V-tail design, the Zephyr is a very unique foamy!

The Zephyr calls for a 3300mAh~4000mAh 3s Lipoly Battery but the fuselage makes it very difficult for that size battery to fit. So we used a TURNIGY nano-tech 2250mAh 3S for our review and for the smaller sized battery we balanced the plane by adding some washer weights that we pulled out of the Bixler. When you purchase your plane be sure to also check your aileron servos and stream-line covers to make sure they are glued down before flying and you're good to go!

Here's some links to the stuff mentioned in this episode:

The Durafly Zephyr V-70

TURNIGY nano-tech 2250mAh 3S


TURNIGY nano-tech 2200mAh 4S


The Bixler


Flite Test Bixler Review

The Fiberglass Fox

How To Balance Your Plane
 
#3
I liked the episode and I could tell you guys felt free to point out the negatives without being overly diplomatic. I do wish you had spent some time going over the setup of the V-Tail and how that impacts flight performance.
 

AvaAdore

Junior Member
#5
4s Maiden Report


I'm going to start this by saying, do NOT fly this on 4s.
Started out with perfect CG with a 3300 4s, everything looked solid. I had a friend hand launch for me, used about 3/4 throttle and it got up fine.
After all was trimmed out I tried a couple of high speed passes @ WOT. I have never seen wing flutter like this in my life, violent and I was expecting the plane to snap a wing or take a dirt nap. Down wind or up wind it would flutter aggressively. The wing itself shows strength with the resin/foam construction and the CF rod plus the glass strip but where the evident weakness is the cavity where the aileron servo is mounted. I don't think trying to strengthen the cavity with resin will fix the problem, the flex in the wing is not the issue, it's the lateral twist.

Another problem I encountered was the ailerons at high speeds were showing huge amounts of blow-back, almost no response at all until the plane slowed. The servos seems to be of good quality and I don't think the problem lays with them, its the length/size of the aileron plus it is still foam with flex. Also the tail surfaces were evidently twitchy and unstable at WOT, from either too much air speed or thrust from the fan? Hard to say.

All in all, it was a successful maiden, it is a nice flying plane. The stock electrics/setup seemed to handle 4s quite well, speedy and motor were only just warm after a few WOT passes.

So my recommendations:

~360g 3s 35c+ Lipo
High rates, this is a warm-liner at best, it's clear it is a aerobatic sport flyer. Chasing speed with this will encounter a sad panda face.

It's not a plane for beginners, not that it is hard to fly it's just that it's fairly quick, hard to slow down and not self leveling. Fly it within it's envelope and it's a fantastic plane, I am now going to try turn this in to a aerobatic MACHINE. The tail has so much throw to play with

Pros:
Cheep plane with great gear in it.
Fun to fly.
The noise.
Not many models like it.
Awesome aerobatics and decent gliding capability.

Cons:
4s/highspeed instability within the wings.
Fairly specific Lipos needed.
Needing to re-glue most things that were done from the factory.


I'm not going to lie, I was disappointed that it did not fly well with 4s and I don't think the issue could be rectified but now aiming to go for a more aerobatic path with it. Fly's well, holds great lines and glides fairly well for a overweight glider. It looks sexy as heck and sounds insane. I'd buy another, "plane of the year" I'm still yet to feel that but it is a good plane overall.


A follow up with running 3s!

In my opinion, it fly's better on 3s then on 4. The overall weight is only slightly less but for what ever reason the glide and the aerobatic capability is largely better on 3s.
Firstly, the glide. I'm running 4000mah 3s, I had a flight that lasted well over 20 minuets this morning. Blast it up then back right off to a fairly fast gliding circuit, there was almost zero wind and no thermals, just had to use the speed that plane encourages in a glide to keep altitude and not fight it too much with heavy elevator. When flying with power on, 6.5 mins is fairly safe.
The aerobatics are a bunch of fun, most basic IMAC maneuvers it can complete easily, inverted it's great, the only slight improvement I'd like but I already have is a slight increase to roll rate but I already have the servos at max throw. Something to work on
CoG, I found 80mm to work the best for me, the stall was subtle and the plane seemed to fly better, also no trim needed on the elevator.
Thrust tube! Tried a DIY tube, 58mm exhaust, it did quieten it down but I did gain a 15% increase in thrust. The extra thrust is very evident with back to back tests, with and without the thrust tube.

With about 10 flights on 4s with this plane I was not super excited about the plane, with only a handful of flights on 3s I can't wait to get back out there! It flys like a different plane, super fun! The overall speed between 3s and 4s is not huge, mainly 3s I have not encountered any signs of wing flutter like I do with 4s.
For all the people still humping the dream that this plane will do amazing speeds I still highly recommend to buy another plane to do that with. This plane on 3s is plenty quick enough(with a thrust tube it is more so), I think the denial on terminal velocity on a large wing span of foam is the limiting factor.

TLDR: 3s FTW

 
#9
Nice work guys - as usual the "Hi, I'm Josh and this is Josh" delivered. 7 words that I hang out for every week!

On the plane, sounds a bit 'rumpty' to me like the EDF is not well balanced or something. Also the plane seems to sit in the middle of a sleek racer hotliner and a pretty sloper glider with none of the charm of either. I wouldn't say no to owning one but I also don't think I'll be dishing out for one.

Thanks for all the hard work again chaps - you can see it's a passion and you have fun doing it... almost as much fun as I have watching it!
 

lobstermash

Propaganda machine
Mentor
#12
I loved the concept of this from the first teasers. When they released the product video on HK I was really taken by it, especially with that sound. Seeing it on FT makes me want it even more... But I have too many on the list, too many in the hanger and too little money to spend on another - albeit very cool - sportflier...

Best episode for a while, too! Very entertaining and you guys seemed genuinely excited to be doing it.
 
#15
I've been flying, and repairing, the Zephyr for a couple of weeks. Two main things to look out for : Always have someone launch it for you if possible. The stability of the launches are inconsistent. You will notice in the video how on the second launch it dipped and veered left. This is COMMON ! I don't know the perfect solution, I'm still experimenting with trim. Don't balance further back than 80mm.

Also, be very careful on landing. DO NOT land in tall grass. It will rip the wing off. The short dry grass in the video is about as tall as is safe. Notice how abruptly it stopped. The low wing drags heavily and puts a load on the wing mounts often beyond their strength. I 'solved' the problem by mounting a single 1 1/4th inch wheel on a music wire strut angled back. It holds the front of the fuselage and the leading edge of the wing up high enough to not stress the wing mounts too much. I also land only on a paved surface. The wheel allows it to roll out nicely. No wing abrasion with packing tape placed at the contact points.

It is a fun plane to fly and worth the money, but be aware of the weaknesses.

I also fly a Dynamic S. Much "calmer" and less dramatic on launch and landing. They are quite different models. Criticizing one over the other is pointless.

There are 78 pages, at the moment, on the Zephyr here:

http://www.rcgroups.com/forums/showthread.php?t=1639354
 
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#16
I also fly a Dynamic S. Much "calmer" and less dramatic on launch and landing. They are quite different models. Criticizing one over the other is pointless.
I just mentioned that since they LOOK ALIKE, the prop version (dynamic-s) seems more efficient than the EDF wich flight times are much shorter.

Do you care to compare the flight of both of them ? are they equally fast ? how is the climb rate ? agility ?


welcome to flight test forum !!
 

banjo328

Junior Member
#19
I just mentioned that since they LOOK ALIKE, the prop version (dynamic-s) seems more efficient than the EDF wich flight times are much shorter.

Do you care to compare the flight of both of them ? are they equally fast ? how is the climb rate ? agility ?


welcome to flight test forum !!
Yes, you're certainly right about them looking alike. You are also right about efficiency in terms of power-on duration. When I use my preferred 3S 2200 mill. batts. in both of them, the Zephyr gets about 6-7 minutes before power cutoff while the Dynamic will go over 10 min. but this is dependent on how I use the throttle. I have thermalled the Dynamic, resulting in much longer flight times but have yet to find one strong enough to thermal the Z. This morning I tried a new 2650 mill 3S in the Z and got 8:15 before power cut off. The prop is more efficient than the fan but I would say that the Z glide angle is just as good as the D., it just ignores lift more.

Speed-wise I can only judge by 'eye-ball' but I would say the D is faster in the climb but I'm using a 12 X 6 APC rather than the stock prop and the speed and climb was noticeably improved over stock and is better than the Z.

Agility/roll rate is very similar to my eye. I use reduced throws, no expo, so neither one rolls as rapidly as the videos.

But the one BIG difference in my experience is the predictability on launch. The D. goes up the same way each time, undramatically, while the Z does something different each time. For example; this morning using a helper to launch, on the first launch the Z. dived instantly on release to the ground , 4 - 5 meters out. On the second launch, holding the nose a little higher it did its common wild gyrations, rolling, porposing, etc., but it was just high enough to catch it and it went on to a good flight. Elevator and aileron trim were set to neutral both times. 75mm balance point, 5 mm further forward than when using the 2200 batt. This is the main reason that every Z flight is an unpredictable challenge compared to the D.
 

skyland

Junior Member
#20
Zephyr Puller Mod

I never felt like the Zephyr performed well or lived up to the hype. I crashed it a few times trying to come in slow only to have it tip stall and get banged up on landing. After one particularly bad crash, I found that the EDF wasn't producing enough thrust or something and it REALLY lost it's mojo. Then I crashed it so bad, I snapped the nose off. Feeling frustrated, I almost threw it in the garbage, but decided to revive it instead. I pulled out the EDF, put a new Depron nose on it, and mounted a Hacker brushless outrunner up front and made it a puller. Now it flies better than it ever did as an EDF. More agile, quicker acceleration, and a lot more fun. I think the prop wash over the wings makes it more maneuverable and responsive. Here's some footage of the Hobby King Zephyr Puller. It's just a head cam, so it's not the best camera work.

http://youtu.be/DtnL8zwTBbw

Zephyr Puller.jpg