cobratraxxas69

My Feedback: (31)

What do you guys think of this bad boy?


http://www.hobbypeople.net/gallery/116520.asp


Looks pretty fast to me!!!

How fast do you think it will be on the 6S pack and 6S motor it recommends at the bottom of the web page????

opjose

I picked one of these up a few months back when they were selling for about $80.00/ea.

I noticed that on one of the forums someone suggested getting an HET FAN and matching motor for the 6S setup.

Since I have a bunch of 4S packs I went with the HET 2W20 motor instead, which has higher RPM's.

Last Sunday I flew this plane for the first time.

I built a bungee launcher for it. Unfortunately the tubing I used was too thin, and did not provide enough power to pull the plane enough ( I'll fix this later ).

One guy offered to throw it for me on it's maiden flight. I had quite a number of spectators around for this....

I told him to throw it just slightly above level and forward as fast as he could.

Unfortunately he threw it almost straight up instead. I thought, there goes my Spear, nose first into the ground into little pieces.

Well since I had the throttle on full, the plane, started to lower it's nose, and as it did so it picked up speed. Within half a second it was flying.

Another half second after that I had to bring the throttle down, because I could barely see it!

It took off like a rocket!

I brought it around to trim it out, and after two passes I had it flying pretty level. I had the throttle at almost idle for these passes.

Then I brought it around for a full speed pass.

I kept hearing "Amazing", "WOW!", "It is like trying to control a BULLET!".

I had a grin from ear to ear at this point.

Everyone at our field stopped what they were doing to watch. Even a number of Turbine Jet owners came to comment that my little plane was probably faster than theirs. They were quite impressed.

This plane gets WAAY out of sight within an eyeblink. Fortunately I was able to track it, but most observers lost it in the sky just after a pass.


After about 4 minutes I noticed a sag in the power output, so I decided to land it ASAP.

I did not know how much power was left given it's first flight so I decided to only make one attempt to land with no practice passes.

The plane came in VERY hot and flipped all over the place.

Fortunately the damage was minimal as I had planned for this ( see below ).

I was quite impressed with the plane though.


Suggestions:

If you do buy one I highly suggest the following.

- The Ultrafly suggested combo is fine, but the HET stuff is SOOO much better and the plane flies far faster.
- You need adecuate packs, I landed after 4 minutes on a 3750mAh 14.8v 20C pack!
- Do NOT install the ailerons as the manual says! See below.
- Apply tape ( I used aluminum duct tape ) to the middle bottom of the fuse to protect it.
- Install wing tip guards.
- Make your own EDF mount, the one provided is WAAY too thin. I used 1/2" thick Basswood for mine!
- I also used Dap "Tak Foam" which does not expand as much as standard building foam, to seal the area around the EDF. This worked GREAT.
- Use THICK wires for the ESC extensions you'll need.
- Make sure the C.G. is no more than 100mm. I needed 1oz of lead in the nose in addition to my battery pack.
- A bungee launcher is a good thing!
- I used the recommended throws for the elevons measuring "up" elevator input. Mistake see below!

Aileron/Elevons:

I positioned the servos within the wing temporarily, and cut out an ovoid shape on the TOP of the wing for the servo horn.

I basically installed the servos horns to protrude from the top of the wing, and I did not cut out the material for the bottom hole.
This prevents damage to the horns at landing. Mine were just fine after my rought landing.

Wings:

I installed the wings in place after wiring and setting up the servos. Because I knew the first landing may be bad, I did NOT epoxy the wing in place.
Instead I drilled through the fuse into the wing pegs at the marks already in place.

When my plane landed the pegs broke where the screws went into them, but it protected the plane from extensive damage.

Now that I have it trimmed out, I am going to epoxy the wing in place.

Throws:

I would recommend setting your radio up to use the max recommended throws as your low rates.

Then reserve the high rates for LANDINGS and increase the throws ( particularly stick back, up elevator to at least twice this! ).

I basically did not have enough up elevator authority to keep the nose up and slow the plane for a landing.

While the plane uses Elevons, when my JR radio is set up for an Elevon plane, I can adjust the "elevator" control separately.

This permits me to dial in more control movement when I pull the stick back ( as for a landing not a loop ), than when I roll the plane.
On my next flights I'll use twice the recommended movement JUST for "stick back" ( up elevator ) for my high rates, when I attempt to land.

cobratraxxas69

My Feedback: (31)

Nice report opjose!

opjose

Additional notes in case anyone is interested.

After recharging my 3750mAh pack, I discovered that the plane had only used about 2100mAh after my maiden flight.

That means I can add about 2 minutes to my timer.

Also the International Sport Flyer magazine review suggested 3-4 mm of reflex instead of the 1mm suggested by the manual.

I set mine to 5mm thinking that this would be safer for a bungee launch.

My plane climbed WAAY too much until I trimmed the nose down, so 2-3mm was just about right for me.

While I should have used 12G or so servos, I noticed that the manual showed 9G servos. I used some inexpensive 9g Tower Pro servos and these worked just fine with the recommended linkage holes... ( though I have mine on the top of the wing ).

Quite an impressive little plane. I wish Ultrafly would re-issue it with all of the minor problems fixed.

At some of the prices it is going for WITHOUT the FAN and motor, I find it overpriced, given the construction.

However at discount it is not too bad. At the 80.00+ it was selling for a while back I considered it a "must have".

Hobby-People has it now for $129.00 which I still find high.

If they drop the price again, I'm going to pick up another one. ( Yeah it's THAT much fun! ).

cobratraxxas69

My Feedback: (31)

How fast would you say your plane is in straight and level flight?

opjose

Remember that we tend to overestimate the speed of our planes.

That said with prior EDF's I flown, they never have seemed that fast to me, yet onlookers have come up to me and said, "that flies pretty fast".

The Spear felt REALLY fast to me.

And the guys that were out with their Turbine jets estimated that I was easily in the 150-180mph range or more. Another thought that it might be faster as it left our field area more quickly than their planes at full power. They were quite impressed.

One guy also estimated a 1.5-1.8 to 1 thrust ratio.

All of this is in line with the original post I saw that recommended the HET setup for extra speed.

I saw this at RCG and the poster said he was getting 180 mph.

I know the HET setup is at least 20-30% faster than the Ultrafly setup, and the Ultrafly setup is supposed to hit 130-150mph.