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Author Topic: Freewing 80mm fans (My Labor Day fly in)  (Read 276 times)
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Konrad
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« on: September 28, 2017, 11:58:20 AM »

Over the Labor Day weekend I was flying in the Denver area at two of the better flying field in the USA, Chatfield state park and Arvada fields.
These fields are between 5K and 6K feet altitude. This rarified air does tax the power efficiency of the EDF system.

I keep a Freewing F-5 and Mirage at the family homestead for my semiannual visits. Because of the thin air and the poor efficiency of the stock Freewing 80mm fan I’m using Jetfan rotors in my 80mm Freewing jets.
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=22133.0
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=21197.0

Luck would have it that some of the guys had brought out some of the newer Freewing 80mm stuff, an Avanti S and A10. Much to my surprise I was impressed to see that Freewing is trying to improve the efficiency of the 80mm fan they offer in their latest jets.
http://www.rc-castle.com/index.php?route=product/product&product_id=6826
http://www.rc-castle.com/index.php?route=product/product&product_id=6904

I just knew that the A10 was going to be a pig in the thin Denver air on the Freewing 80mm fans, the A10 is designed for 90mm fans. Well, much to my surprise this wasn’t the case. I watched in awe as the A10 made strong vertical up lines and pulled high “G” turns. And what really got my attention was the landing, the A-10 warthog as set up by Freewing is a bear to land. The owner made a good but firm landing and then the A-10 became a bucking bronco bouncing on every end of the plane. The pilot was a bit late on bringing on the power, so late that I thought the A-10 was going to snap on power up. Didn’t happen, the twin 80 fans dug into the thin air and pushed the A-10 back into the air with authority! This was clue that the fans were not the same ones I fond in the F-5 and Mirage!

The landing had broken the landing gear (The Freewing A-10 has poor retracts). As I usually bring all my spare parts to the field I had what this pilot needed to get his hog back into the air. While helping him reassemble his undercarriage I took a quick look at the fans and noticed that Freewing had moved away from that awful 12 bladed rotor I had found in their scale jets and was using a 9 bladed rotor. This explains why the Freewing 80mm fan was performing much like their larger 90mm 12 bladed fan. With the 9 bladed rotor the efficiency is vastly improved with little loss in “sound quality”!

I also saw the smaller FMS 70mm A-10 fly. It has nothing to apologize for. It also looks to be better engineered than the Freewing as it was proving to be much more durable.

I later had the opportunity to fly the new 80mm Freewing Avant Si. Again Freewing has made some noticeable improvements in their product line. With the Avanti S, Freewing has made the set up recommendation in the manual applicable for maiden flight. This is in stark contrast to the normal Freewing practice where the set up details are sure to drive parts sales. The Avanti I flew was still a bit nose heavy at  6mm further aft than what was recommended in the manual. This actually is the proper way for the OEM to set up a model. Give the new owner of a model a chance to fly the ship should he find the controls be too responsive or out of trim. I also noticed that the 80mm fan had more thrust than I recall seeing with the standard 12 bladed 80mm Freewing fan found in most of their scale offerings. Looking at the fan, the blades are reshaped. The fan still has 12 blades but the tip are broader and it looks like the trailing edge of the rotor is placed closer to the housing stators. While the noise is up it is still pleasant (no banshee scream).  I don’t know what the amp draw or thrust numbers look like. But with the new 80mm fans one can actually fly some of Freewing 80mm with the stock fan.

These new rotors are really diving home the deficiency of Freewing’s parts description. Just with the 80 mm rotors I have, the drive pads vary in diameter, number and size of drive flats. Now Freewing has to, or should, identify the blade configuration. The old description of the rotor being for an inrunner or outrunner never was adequate, and now it will be down right frustrating trying to size and replace damaged fan units.

These new Freewing 80mm fans have almost persuaded me to get some of the new freewing jets for myself. This is actually say a lot as in the USA Freewing is in an exclusive distributor agreement with the despicable firm MotionRC. The issue with MotionRC aside the new Freewing jets just mis the mark with me. The 80mm Avanti S is on the small side and the twin 80mm A-10 is a bit on the large side.
https://www.motionrc.com

Then on Monday I was again at Chatfield and I witnessed a real wicked (nice) looking jet. It was the large Taft 90mm Super Scorpion! The size and performance was perfect. Unlike most of Freewings offering the Taft Super Scorpion has been properly spec’d to use 8 cells in a 90mm jet. 6 cell really is too low a voltage even for the 80 mm jet. It is just insane to try to drive the 90 mm fan on 6 cells as the amp draw has to be way too high to get any meaningful performance.  The Taft Super Scorpion while not a speed demon has great vertical (remember this is at close to 6K feet) and lands real nice and slow. Not nice and slow for a jet, but just real nice and slow! I saw that Banana Hobbies had the Super scorpion on a labor day sale for $260. This was cheaper than the much small 6 cell 80mm Freewing Super Scorpion as sold by MotionRC.

Now I need to give Alex at Banana Hobbies a shout out for great customer service. By the time I made it home to San Francisco the Taft Super Scorpion was no longer on the Labor Day sale. Alex honored the Labor Day sale and I had my new Taft Super Scorpion in three days.
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=22457.0
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