Replies to This Discussion

Permalink Reply by Dan S on September 7, 2011 at 10:53pm

OK, so I might have answered one of my questions already.  Cruise speed on the Skywalker seems to be around 70km/h?  Is that a good long-range cruise speed estimate?

 

 --Dan

• ▶ Reply

Permalink Reply by Toby Mills on September 8, 2011 at 12:00am

I as in a very similar situation to you about 4 months ago.
I started with a skyfun. I bought two airframes thinking I would probably trash one (I was right).
I more recently added a 3300mah battery to give a max endurance of 38 minutes at 45kph and a max round trip range of 20km.

I am now building a ritewing zeph after having such great success with the skyfun and looking for a 50min to 1 hour duration at 80kph.

If you go much slower it will Kay much longer.
Also think massive prop with low rpm motor for max endurance with a lower top speed.

• ▶ Reply

Permalink Reply by Dan S on September 8, 2011 at 4:30pm

Is the skyfun an efficient airframe for long-range?  It seems like it is more suited for speed than range/endurance.

 

Do you think it could hold 2 3300mah batteries?

 

 --Dan

 

• ▶ Reply

DeveloperPermalink Reply by Doug Weibel on September 8, 2011 at 7:18pm

The Skyfun is tough for long range.  It will be difficult to get the CG right with a large battery.  You could fit two 3300's, but there is no way you would get the CG right with them, at least under the stock canopy.  It would be much better with a custom canopy giving more room towards the rear...  

The FPV guys who have worked at it report 40+ minutes for a Skywalker.  I get 25+ on mine, but haven't really worked at it.  

• ▶ Reply

Permalink Reply by Toby Mills on September 8, 2011 at 7:51pm

You can mount a single 3300 to the bottom of the skyfun fuse (externally) which gives you a lot of CG options but 2 x 3300 would be too much for the wing. The extra endurance would be lost by the extra power you would need to maintain enough speed to stay aloft. Landings would be more like high speed crashes as well.

3300 is up near the maximum for this airframe, maybe 4000 tops but landings will be hard. My skyfun with a 3300 is a handful to land safely but in the air is fine.

 

The skyfun is a flying wing and is capable of very slow speed flight for endurance, but it cannot lift a large amount of weight.

 

80kph for 1 hour will require an airframe signifiantly bigger than a skyfun, probably closer to 2m wingspan with a total weight between 1.5kg and 2kg (possibly more). Think BIG. 80kph requires a lot of energy to maintain that speed, especially if you want to do it efficiently (ie with endurance). You will need a big prop turning at a medium speed (not a high rpm screemer).

If you are new to RC then don't go for something this big straight away, do it in two stages. Buy a cheap small airframe to get to grips with, then once you are ready, upgrade to a bigger airframe.

Trust me, you are going to crash a LOT, you might destroy two airframes before you are comfortable enough with all the different aspects to invest in the kind of airframe that is capable of 80kph for over an hour. There would be very few people here who's first ever airframe is still in flyable condition.

• ▶ Reply

Permalink Reply by Dan S on September 8, 2011 at 9:06pm

Toby,

 

I totally agree.  I am going to start with something simple, probably either the Bixler or the SkyWalker.  It looks like the skyfun might be a bit much for the first build, plus I am looking for something with plenty of interior space and as much range as possible (in a beginner aircraft).

 

Do you think a Bixler or Skywalker would be a good place to start?

 

 Thanks,

 Dan

 

• ▶ Reply

Permalink Reply by Dan S on September 8, 2011 at 11:22pm

Does anyone know what the glide ratio for the Bixler or Skyfun is?

• ▶ Reply

Permalink Reply by Dan S on September 11, 2011 at 9:25am

So it appears that the Bixler and the skywalker are significantly different aircraft (I thought they were similar).

 

While being close to the same size (the Skywalker wingspan is a bit larger), the Bixler flying weight is quoted at 650g, and the skywalker flying weight is quoted at 1.8kg!

 

Skywalker:

http://webcache.googleusercontent.com/search?q=cache:sydQajcJWrUJ:w...

 

Bixler:

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=...

 

If I don't have a lot of (or any) FPV gear in the skywalker, I was thinking I could load it up with huge batteries for more range.  Although, maybe since that requires more power, it would not be much better than the Bixer.  Does anyone with more experience have any knowledge on this?

 

Thanks,

 --Dan

 

• ▶ Reply

Permalink Reply by Stephen Wuest on October 2, 2011 at 10:55am

A comment on wing mounted motors --

 

I tried the nitroplanes UAV (55") and a slightly beefed up 3xx42mm motor. The thrust line was too strongly down, and the plane wanted to fly outside loops.  

 

So even if the pod is big enough to fit more batteries, be careful of increasing the watts of the motor to gain more speed for more lift to carry the batteries, in a wing mounted motor design.

 

I would like to see a tail pusher design with a drive shaft, so the motor and the batteries can be positioned wherever it's handy, and the thrust line is completely down the center of the body.

 

Stephen

• ▶ Reply

Permalink Reply by Brad Smith on February 7, 2012 at 10:32am

i read somewhere where they shimmed the the bottom of the motor mount to correct the thrust line problem might be worth a try

• ▶ Reply

Permalink Reply by Bradley Muller on February 7, 2012 at 7:41am

Hi Dan,

I am also just starting out with an FPV plane. Which plane did you end up buying?

• ▶ Reply