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Jun 09, 2009, 09:56 AM
Gravity is just a theory.
Capt Crash's Avatar
Thanks for the info. I'll look into it after I take the machine up. I had a friend of mine who has a lot of experience help me get it set up. With a GMS .76 up front, it balanced easily by moving the battery around. The GMS is turning a 13 x 6 MA prop and hooked up to a Bisson Pitts muffler. The motor dialed in rather easily; we focused on the idle needle to get the transition smooth and reliable. At WOT it was turning 11,400 on Omega 5%. So with much fear and trepidation we plan on taking it out on Wednesday for the first flight. The GMS/Pitts combination is surprisingly quiet and sounds good.
Last edited by Capt Crash; Jun 09, 2009 at 01:05 PM.
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Jun 13, 2009, 12:17 AM
Gravity is just a theory.
Capt Crash's Avatar

Successful maiden...

After a few days of rotten, atypically wet weather in Utah, we finally caught a break today. Area 51.5 was out of the question, soaked and sticky as it was. So it was off to the Jordan River State Park modelport.

The clouds were starting to gather when we put the plane together and fueled it up. With the balance point set at the factory specified 120 mm from the root rib leading edge, we went through the runup and got the plane out onto the runway. I rolled onto the throttle and she floated away gentle and easy, with the GMS .76 pulling nicely.

Under midrange power, the plane tracked well and handled predictably, but when I rolled off the power to get a descent, I got an increasing nose-up pitch. It was tail heavy, and I had a devil of a time getting a controllable descent out of it. I shot a couple of approaches, and finally, on my third approach, I got it to come down, but belly flopped (very gently) into the tall grass right next to the runway. No damage but to my ego, so we did the walk of shame, brought it back, and moved the battery to the spar tube.

The next flight was dramatically better. Nice smooth takeoff, nice turns, and backing off the throttle delivered a rock steady, predictable descent. I went around a few more times, then turned base to final, backed off the power, and she settled right down and came on in. A bit of back pressure and the plane eased onto the mains for a smooth rollout and taxi back.

The weather continued to deteriorate, so we packed it up. With the plane properly balanced, it's ready for more. The .76 seems more than adequate; takeoff was easily accomplished as I passed through the 50% throttle point, and at this power level, the plane climbs easily. Hope to get more serious about pushing the envelope once I check it over thoroughly and when the weather cooperates, but initial impressions are good.
Jun 14, 2009, 10:15 PM
Boring holes in sky & runway
Waterbug's Avatar

Suh-weet, Cap'n Crunch- another Phoenix airborne!

Glad you got a hole in the weather. Glad you got 'er in tail heavy.
Sounds fun. I'm surprised she gave you trouble at 120mm CG. I've been creeping back from there toward 125mm lately. Did you measure from the wing root- i.e. near the fuselage? If you measured near the tips it would be very tail heavy. Many have complained about the nose up attitude as you slow it down, but it could also be that you have downthrust that makes it pitch up when you back off the power.

Anyway, I'm sure we'll hear more. When it trimmed out on the second flight, did you end up with a bit of up or a bit of down elevator? That can be a clue.
Another is whether or not you have to push the elevator much inverted. I'm currently flying with no downthrust at 120mm CG and it just flies great inverted with the sliiiightest push. Nice aerobat, though it seems to have limited Knife Edge climbing ability.
Jun 16, 2009, 03:07 PM
Gravity is just a theory.
Capt Crash's Avatar
I did the CG measurement from the wing root per the Phoenix specs; we marked them and put it on a Great Planes CG stand. A better pilot than I would have probably had no trouble with the plane as originally balanced; I just don't have that much experience flying 3D. Under 50% throttle, it flew very well, but rolling off the power brought out the tail drop.

I do have 1 degree of downthrust in the motor mount, but it doesn't seem to produce much of a change. Under power, the plane flew predictably in either configuration. The reduced power setting demonstrated the difference: with the batt moved forward 4 inches, it dropped the nose rather than the tail.

I'm looking forward to getting more time in with this airplane...
Jul 16, 2009, 09:20 PM
Gravity is just a theory.
Capt Crash's Avatar

Building time with the Phx Extra...

I've managed to get more flights in with the big Extra, and I'm shaking a lot less now. The GMS .76 is swiss watch reliable. Running it with the cowl is a cinch: after fueling, I prime the engine by opening the throttle a quarter, plugging the carb intake with a vinyl cap, and spinning the motor for a second or two with the starter. When I remove the cap, I check for fuel in the throat (if it's wet, it's ready). Throttle to idle, hook on the glow stick, and bump it with the starter, and it rumbles to life every time.

The most amazing thing about this airplane is the very gentle landing. I can't believe how this big airplane will SLOW to just a crawl, seemingly hanging in the sky. I'm just not used to seeing something this big going so slow. I keep carrying too much power and speed into the base-to-final turn. Still, landings are a joy because it will settle down and float on in, with sweet three pointers and straight, easy rollouts. Just amazing for such a competent airplane.

I've got a lot to learn with this big sled as far as pushing it aerobatically. I replaced the factory pilot because my buddy's girlfriend said he looked scared. I could understand his fear. Still working out the kinks in the machinery - the factory gas tank is a bummer because the rubber plug developed a leak around the plastic fuel lines. Also have had some screws loosen up on flights, so still trying to get everything secure and solid. Still, I'm really enjoying this airplane.
Jul 17, 2009, 02:57 PM
over user
Stevo Revo's Avatar
Thread OP
I finally decided to give my plane some real nuts.........I pulled the .90 and installed a 1.20 ax. I have a Seagull edge 540 that is very similar to this model and has a 1.20 in the cowl. It is a total blast to fly. I thought I'd try the same with the Phoenix extra.

I took a few shots for comparison's sake between the .90 and 1.20. As you can see it needed a bit of firewall modification to fit the ax muffler. I have had good luck on my edge with the muffler so I didnt wanna throw down another $60-$70 on a pitts muffler that I didnt feel was needed.

Balancing this monster was a bit of an issue, I ended up with the 5 cell AA rx pack in the tail.... I mean..... if it was any farther back it would be in the rudder. I actually installed it with a bit of surgery. I opened up the bottom of the fuse between the tailwheel block and the elevator servos, and pushed in some foam and stuck her in. I capped it off by ca'ing the original piece back in and then covered it up with a scrap of blue I cut out from behind the canopy.

I ran a break in tank thru her in the yard the other evening. The next chance I will be able to get to the field to try her out will be tuesday. So no maiden report till then!

Im just glad I got it in finally!!!

Glad to see that everyone is enjoying their extra's..... I anticipate it will be more fun to fly now than my edge....... we will see!!

Oh and as far as the tail drop when off power..... that has alot to do with this model's wing incidence. It is rumored that if you raise the trailing edge of the wing by 3/32 to 1/8 inch, it will drastically improve that tendancy..... I plan on making the mod.... after I get the 1.20 dialed in.
Jul 17, 2009, 03:02 PM
Registered User
RMS's Avatar

So you decided the DA100 was too much for it?

Aug 04, 2009, 08:33 AM

Some doubts on this extra

Good morning ...

In previous days I buy the extra Phönix models 330, and I have some doubts that I would like to settle here ...

- How does this aircraft with the GMS .76 engine with BISON mufler ?... or this brand of engines is not recommended ....
- Be that with this engine can make the 76 GMS 3D?
- I have seen some photos of this forum, and I noticed that one of them have adapted a smaller tank on the wall of fire ... I could show it to this tank ..
- You can install or standard servos will require high torque servos ..

Thanks ....
Aug 05, 2009, 06:38 PM
Gravity is just a theory.
Capt Crash's Avatar

I'm flying my Phoenix Extra on the GMS .76 with the Bisson Pitts muffler. This setup is fine for "classic" aerobatic flying, but not adequate for full-on 3D flying. You'll need at least a .90 for that; check out Stevo Revo's retrofit with the 1.20 for some serious power. I'm just using standard servos in my plane, but they seem fine. For a bigger engine, maybe high torque servos would be the right choice.
Oct 12, 2009, 07:19 PM
Boring holes in sky & runway
Waterbug's Avatar

Spoilerons help to speed up the landings

Glad to hear its going well, Capn. I agree that this plane built light lands at a painfully slow speed! For those windy days when a slow landing is on the edge of a crash: I have had very good luck speeding up the landings with spoilerons, a.k.a. both ailerons up from neutral using the flap switch.
Normal flaps are never useful with my <7 lb build-it just hops off the groud in 20 feet or so. I put the ailerons up 15mm and then 20mm with the 3 position switch. At 20mm I find 1.5 mm of down elevator with the same switch is about good. So normal flying in position 0 and both ailerons at neutral, light cross winds I go to position 1 for 15mm spoilerons with 1mm down elevator, heavy or puffy winds I go to position 2 on the same switch for 20mm spoilerons with 1.5mm of down elevator. Works like a charm. At full spoilerons, it needs a click or two of throttle to keep flying but rejects the puffy wind because it is now landing at more like typical trainer speeds.
Oct 29, 2009, 08:29 PM
Boring holes in sky & runway
Waterbug's Avatar

Prop speed helps knife edge!

I have been flying with a Saito 91 4 stroke and a 16 x 4W APC with great hover/3D punchout. I did not like the knife edge at standard 120-125mm cg per plans because it could barely hold and not climb in KE. Then I tried a 15X6 Zinger and a 14x6 APC, still no joy on KE but hover/3D still OK. Then I tried a 14X7 APC and it fixed the KE performance. Just a little extra prop blast made the difference. Still hovers very well, but with less punchout. But climbing in KE is important for 3D so I like the compromise.

Prop ________RPM ___Pitch Speed (theoretical from feet per rev X rpm X 60 / 5280)
16x4W APC __8800 ___33.3 mph
15X6 Zinger _ 8700 __ 49.4 mph
14X6 APC ___ 9900 __ 56.2 mph
14X7 APC ___ 9100 __ 60.3 mph

I think that it is the pitch speed doing it. The 14X6 didn't load the engine enough so the 14X7 did the trick! I got that hint from an unofficial Saito page ( where the author suggested the hard to find 14X7 as the ultimate prop for a Saito 91. I am in agreement with him! Maybe that page can be useful for one of you guys.
Last edited by Waterbug; Oct 29, 2009 at 08:35 PM.
Apr 24, 2011, 12:51 PM
Registered User

phoenix 330

HEY!! Where did everyone go??? What happened when Steve put the 120 in his plane? Why did you all disappear some of us inquiring minds need to know
I just bought the plane from tower and was going with either a super tigre 90 or a webra 1.20 . I was thrilled that you were going with a 1.20 because I needed to know how it does. It is my first plane that is not a warbird so any help would be appreciated. I would love to go with the 120 but really want to know how steves did.???
Apr 24, 2011, 01:02 PM
Registered User
RMS's Avatar
If you mean Stevo Revo........... As far as I remember from speaking with him. The plane was a blast with the OS 1.20ax on it (hope I don't have it confused with his edge 540). I am pretty sure he could do some 3D stuff with it pretty easily.

He may have retired the plane or sold it. He is into the 50cc stuff now. For the short time he's been flying, he's a heck of a good flyer. There are a bunch of youtube videos with him flying his planes. I think if you search for trollhdtv or something like that, you'll find videos of his club. Cool stuff. But I shouldn't speak for him, I am sure he will reply when he sees your message.
Apr 24, 2011, 09:59 PM
Boring holes in sky & runway
Waterbug's Avatar
Last post by Stevo I see is on 9/26/09 @RCU, not to hyjack or anything.
There the thread is slow but heart still beating, post a day kind of stuff.

If you are used to warbirds, the extra weight of a 120 shouldn't alarm you.
These will rock on a decent 90 2c or 4c engine from what I have experienced (4c) and read (2c). There's a video waay back where a guy is hovering his Phoenix Extra beautifully with the fin at Knees altitude on a 90 2c.
My knees woulda been a-shakin'!

Cheers, wheels down!
Apr 25, 2011, 08:01 PM
RC Addict
rmsingh's Avatar

Phoenix 330s Extra came in last week

I received my SK 90 from china today complete with pitts muffler. I will be using Steve Revo's build from this thread as a guideline.
The Extra's instructions are sparse.
1st gripe > vertical stab did not line up properly. I had to dremel the the block and added wedges to get to fit in the block straight and true. (maybe I should not have glued the block at the same time as the horizontal stab). Looks like someone(me) took a chainsaw to it.
2nd gripe > The rudder has a hinge at the bottom that goes in to a slot in the fuse. When I opened the covering to expose the slot, there did not appear to be any material inside to glue the hinge. I glued it anyways and will secure with a bolt and nut later.
3rd gripe > The linkage hardware requires the carbon fiber pushrods to be CA glued to the brass links. Maybe it's just me but I don't think any pushrods on an aerobatic plane should be CA glued. I will be using 1/8" metal pushrods.

That's all my gripes.

On the up side > The covering quality is very good and the construction appears to be solid.

The SK 90 has no instructions but I was able to download this here
The instructions says to use a medium heat long glow plug, but people seem to have good results with the OS #8, so that's what I'll be using.

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