Some advice on flying an EDF with some quirky flight characteristics.

flying saucer · August 21, 2012, 01:04:27 PM

Agree with Pat/Michael

Start the loop in a dive to build up speed.

thehaze · August 21, 2012, 03:54:47 PM

Quote from: flying saucer on August 21, 2012, 01:04:27 PM
Agree with Pat/Michael

Start the loop in a dive to build up speed.

That's not what they are saying at all.

But yes, if speed was an issue, diving before the loop, or half loop, would increase the speed of the aircraft.

Michael · August 21, 2012, 05:55:29 PM

Whether speed is the issue or angle of attack is the issue, the point is, the model is stalling at the top of the loop because of improper airflow over the wings (I think).

The idea, is to prevent the stall.

A larger diameter loop implies less elevator input, and you may need more speed to complete a bigger loop.

thehaze · August 21, 2012, 11:44:12 PM

Well, I took the F20 to TEMAC tonight to work out some of the bugs and well let's just say that I won't need to worry about this issue any more with this plane.

Got the plane up on step and flew it in the pattern for a bit. Switched to low rates on the elevator and managed to pull up and into a nice round half loop. So far so good. I'd estimate that the plane gained about 150 ft of altitude, no sign of a stall or snap. Rolled to right side up and headed parallel to the field. Reversed direction and climbed into a half reverse cuban 8. 45 deg climb, roll to inverted at 300+ft, reduce throttle and pull up elevator to begin a descending half loop. As the plane began to descend I knew something was wrong. The plane seemed to skid (not sure how else to describe it, and I lost all control authority on the elevator. Reduced throttle to zero and flipped to hi rates and still could not exit the dive. The plane impacted the beans and was ripped to shreds. Interesting though was that when I found the fuselage it was evident that the plane never impacted the ground as the beans were stuffed in the ducts and they stopped the plane dead in it's tracks, suspended a couple feet above the ground. The deceleration was so sudden that the battery actually ripped through the nose and traveled about 20 more paces before coming to a rest on the ground. The plane is as Ronnie would say "a write off" although all the electronics (save one servo, who's lead got sliced in half) are still viable.

As I sit here I'm trying to sort out my thoughts on this crash.. And here's what I've come up with.

1. Some planes just don't fly well. This one, as much as I liked how it looked, was not a very competent airplane. I could have just flown it in the pattern and enjoyed the speed but the way I figure it, if a jet can't execute those basic moves, then I don't want it. I'm not sure if there was anything else I could have done to save the plane after I executed the descending half loop. I suppose if was higher up I could have but honestly, I started the move at 300ft which in my estimation is sufficiently high enough to pull this off.

2. Well... this plane just sucked.

The good news is that I have all I need to put together a nice 54mm edf. Any suggestions?

flying saucer · August 21, 2012, 11:45:18 PM

Quote from: thehaze on August 21, 2012, 03:54:47 PM
Quote from: flying saucer on August 21, 2012, 01:04:27 PM
Agree with Pat/Michael

Start the loop in a dive to build up speed.

That's not what they are saying at all.

But yes, if speed was an issue, diving before the loop, or half loop, would increase the speed of the aircraft.

Actually Mike if you look on the first page, Michael R. says exactly this.

Anyway it's now a moot point. Although I didn't see the crash, if it's any consolation, I don't think it was a speed issue either, I'am leaning more toward the model itself is simply not capable of tight aerobatic manoeuvres.

thehaze · August 22, 2012, 08:01:45 AM

Yeah, i found some posts on rc groups where guys reported losing their planes in the same way. The consensus its that there's most likely a design issue with the plane. I've been less than impressed with the manufacturer of this model lately, so I think I'm going to avoid them for a little bit.

I hear that the phase 3 F16 will easily accept the gear from the tiger shark. The airframe is well proven app i might give that one a try. Anyone know of a local shop that Carries this line?

Ededge2002 · August 22, 2012, 09:05:50 AM

Sorry fir the loss. It did always look great in the air.
I do like the caption at the bottom of the photo that reads "frightening scenes".

piker · August 22, 2012, 09:53:33 AM

Oh, now I see the problem! It's made of styro-foam!

Robert

thehaze · August 22, 2012, 11:05:16 AM

Quote from: Ededge2002 on August 22, 2012, 09:05:50 AM
Sorry fir the loss. It did always look great in the air.
I do like the caption at the bottom of the photo that reads "frightening scenes".

Thanks

I thought that it was fitting. Made a nice photo.

Yeah, it was a nice looking plane. I guess when a model comes with a display stand in the kit, you should consider the designer had something other than flight characteristics in mind when he drew it up.

flying saucer · August 22, 2012, 02:42:51 PM

Ive heard good things about the phase 3 F16, but i don't think it has rudder control so you may be more limited with aerobatics, also check on the EDF size it takes.

If you want to move up from Foam, look into the HET F16, its about the same size but a lot more performance.