Funtana 90

Funtana 90
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Funtana 90 - 3/18/2005 1:30:24 AM

JNorton

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Well you might say what does a 3D plane like a Funtana 90 have to do with sport flying? It's like this. The local hobby shop had it on sale for $199.00. It's a 69.5" W.S. so it's a nice size, and has a 2 piece wing for easy transport in my 4 door Ford Concour. That darn car has less room in it because nothing folds down than did my much smaller Ford Aspire. So in essence the Funtana is cheap, good looking and should be a whole lot of fun. I'm not interest in heavy 3D, just sport flying.

To power it I've purchased a Magnum 90XL 4 stroke for $150.00 on sale now at Hobby People. I like Hitec products so I've purchased 4 Hitec HS-5625 MG digital servos. I'll run a 425 on the throttle. I've read here on RCU that most of these planes come out tail heavy. So I'm going to use 2 Sullivan #584 Carbon Fiber reinforced precision control rods running to each side of the elevators. I'll join these with a flat plate of aluminum having 3 closely spaced tapped 4-40 holes. The center of which I'll use another small section of carbon reinforced control rod going to a wheel on the elevator servo mounted under the wing.

I fly with a Futaba 6XAS which does not have the capability for separate elevator halves and I couldn't justify the expense of two servos mounted in the tail, especially since no one in my club has the Hitec Servo Programmer. If it balances @ 6-1/4" I'll leave well enough alone if not I'll put the rudder servo under the wing also and use a pull - pull on the rudder.

What do you guys think? As far as control throws I was thinking I'd intially use the recommended low throws as my high and use 50% of that for my low.

I'd welcome any comments.

John

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RE: Funtana 90 - 3/18/2005 1:39:16 AM

jrf

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You may have gone a little overboard on the servos, but it should be a really nice sport plane. Be careful of speed though. 3D airplanes are made to fly sloooow. If you go too fast the control surfaces will flutter and you may lose the airplane.

Jim

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RE: Funtana 90 - 3/18/2005 1:55:30 AM

JNorton

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jrf,
Concern about flutter is why I went overboard on the servos. I wanted quick and rigid so I spent money on digitals. I plan on sealing all the gaps and using Robart heavy duty horns making everything as slop free as possible. If I limit the throws do you think I'll still have a problem with flutter?

John

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RE: Funtana 90 - 3/18/2005 2:20:17 AM

jrf

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John:

Flutter is caused by speed. Every airplane will flutter if you go fast enough. 3D airplanes have a low flutter speed because of the large unbalanced control surfaces. Rigid controls and strong servos just transfer the flutter forces to the servo mounts. The faster you go, the stronger the forces will be. The early Funtana 90's had weak aileron servo mounts and many of them self destructed in flight because the servo mounts pulled out of the wing. (If your Funtana has sheeting around the aileron servos, you have the later "improved" version.)

Having said that, you should be OK with that 91 using an 6 pitch prop if you throttle back on the downlines. I wouldn't use an 8 pitch. Be sure and connect all pushrods to the control horn hole farthest from the control surface. That gives the best mechanical leverage and minimizes slop in the control surface at neutral.

Jim

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RE: Funtana 90 - 3/18/2005 10:48:16 AM

JNorton

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Jim,

Ok, I'll watch the speed on the downlines.

I'm thinking of using a 14 X 6 prop so that should fit in well with your recommendation.

I've read everything I could on the cause of flutter and am still confused, except to keep everything tight - free of slop. Your explanation of the stress transferring makes sense.

I'll take the wings out and look at them to see what version they are. The plane should be pretty new as my hobby shop has sold 4 of these this past year.

It was really a spur of the moment purchase. I probably should have bought a stick - but it sure looks pretty. I still have to finish my Hog Bipe, put together another Venus 40 and then I'll get to the Funtana.

John

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RE: Funtana 90 - 3/18/2005 2:33:16 PM

Steve Campbell

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You won't be sorry, John; this is a great model, and flies better than ANY stick ever made.

There are five of these at my field now. IMO, it is one of the best values to be had in an ARF. My buddy has an OS 1.08 in his, and its a great combo. But heed jrf's warning. This plane definitely flies on the wing, and high speeds should be avoided.

You will be amazed at just how slow it will fly, especially with a rearward CG. But be careful there; you can get it too far back before you know it...

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RE: Funtana 90 - 3/18/2005 3:28:50 PM

MinnFlyer

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I would strongly recommend that you set the CG about an inch forward of the recommended 7 1/8". That setting is for extreme 3-D and you will find it difficult to fly if you plan on Sport Flying with it.

Since you don't want to go with two Elev servos, I would suggest putting both rudder and Elev servos in the radio compartment with a forked pushrod for the Elev and either a push rod or pull-pull for the rudder (whichever you prefer). This will take a lot of weight out of the tail to help you get that CG forward.

And again, flying these things fast is a no-no! - But it is one SWEET airplane!

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RE: Funtana 90 - 3/18/2005 5:24:57 PM

JNorton

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Sounds great Steve, I hope I like it as well as my Stick, cause I really like that Stick a bunch. I'll keep an eye on the speed.

Minn - I'd planned on having the CG at 6 1/4". I was going to use two separate control pushrods joined in the front to a tapped aluminum plate and then to the servo. Do you have a source for the forked pushrod, or were you thinking of making one up from something like an arrowshaft with (2) 4-40 wires wyed off the end?

I gotta finish the stuff on my bench. I definitely want to fly the Funtana this spring! You guys are making me think I made a good choice.

John

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RE: Funtana 90 - 3/18/2005 7:03:16 PM

MinnFlyer

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Yes, I was thinking of arrow shaft with a forked end - easy enough to make

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RE: Funtana 90 - 3/18/2005 7:59:26 PM

TManiaci

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JNorton,

Glad to see another F90 lover. You will rock with the servo selections, just keep those linkages TIGHT and with maximum mechanical advantage your control horns will allow. Echoing everyone else... SLOW is this birds world.

Your engine selection is pretty weak, no offense. If you really don't want 3D, you'll be fine. But, this is one canary that loves to 3D. I'm a pattern guy too, novice learning 3D. The thing is, when you have a bird that can go berserk, you will want to go berserk too. The recommended Saito 100 is marginal for agressive 3D, so your Magnum selection will leave you way short. Just a suggestion... think about growth and your ever improving skills.

The CG you are targeting is not happening. 6-1/4 with a light motor like this will require many oz's in the nose to get there. You will find a VERY docile flying creature with CG at 6-3/4"... greasy landings and no funky tail-heavy tendencies in the air. Even with pull-pull on the Rudder, and Y-link on the elevator in the fuse, you are still well behind the 7-1/4" factory CG, which is recommended for strong 3D performance. My "guess" is, you will CG at 7-1/2 or more with your setup plan. A heavier motor (with more power) can fix this better than adding lead. I hope I'm wrong... but don't be suprised. Adding balancing lead to an underpowered plane is not happiness.

Control Throws: I am really happy with low rates at 1" on both Aileron and Elevator, 2" on Rudder. This is actually a little touchy, and I used 40% expo to soften it up a bit. High rates are whatever you can get with good mechanical advantage, but these low-rate settings allow some pretty radical stuff! This thing has WAY more control than you need for good pattern flying.

It is a beauty... and a MAJOR BLAST to fly. I'm new to this too, and totally addicted now. You will not be dissappointed.

< Message edited by TManiaci -- 3/18/2005 8:07:19 PM >

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RE: Funtana 90 - 3/18/2005 9:14:50 PM

joeb102072

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Wow probably the best thread I have read in here with advise to a new F 90 customer. All of the people in here that gave advise I have read their posts in other threads reguarding different subjects on the same plane. All I can say is its all excellent advise. I too have a F 90 but there is no more to say about it except HAVE FUN!!

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RE: Funtana 90 - 3/18/2005 9:15:53 PM

JNorton

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TMan,

quote:

Your engine selection is pretty weak, no offense. If you really don't want 3D, you'll be fine.

Yup, no offense taken. How do I put this. I'm just not that interested in 3D. It doesn't make my blood boil. Now give me two wheels and 140 HP and I'll get a great big grin - bikes do it but cars have always left me flat. I've got decent hand to eye coordination but my reflexes suck. As Clint Eastwood said - we all have to know our own limitations. Or sumthin like that!

Thank you for your control recomendations I'll be using them as my high rates. If the balance is indeed that far back with no servos in the tail I'll be surprised. I can always take the 120 Enya off my Stick if worse comes to worse. This years budget for planes is pretty well blown, got hit with some unexpected expenses.

I'm happy you are having so much fun with your plane flying it your way. I'll expect to be having just as much fun flying it my way. Different strokes.

John

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RE: Funtana 90 - 3/18/2005 10:29:13 PM

TManiaci

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Yea, there is just a sense of pleasure to fly around, with an occasional roll or hammerhead. I am not "jazzed" about 3D either, but I am learning anyway. My son is the 3D maniac, amd we share the planes we fly. I like the challenge, but I really want to become "proficient" with IMAC pattern flight more than 3D.

The throws I use on low rates: this thing flies like a trainer the way I set it up. It is too easy, but I enjoy it like this. Just a note though, don't cut your low rates down too far from there... I would hate to see you get in trouble and come up short on control. I wouldn't set low rates any less that 70% of the low rates I use. Lots of expo really makes it nice feeling though, so you might compensate there.

This bird is REAL pitch sensitive, so just watch for that on your first takeoff. I was rolling in throttle real slow on my first takeoff, expecting it to lift off early and kept pulling back more and more waiting, then whammo... she jumped up and went nearly verticle. Scared the crap out of me. Lucky I have tons of power to pull out (Saito 150). It surely would have stalled and rolled over without it. Now, I roll in power and pull back just a touch and wait... it picks up so nice and easy. Just took a little getting used to.

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RE: Funtana 90 - 3/19/2005 12:26:46 AM

JNorton

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TMan,

quote:

Yea, there is just a sense of pleasure to fly around, with an occasional roll or hammerhead.

That's my definition of sport flying! Although I do more than the occasional roll.

It's fun.

quote:

My son is the 3D maniac, and we share the planes we fly.

I've been teaching my son to fly. We were out at the field 3 times last year. On the final outing he had three sucessful take offs and landings. I was still on the box but never took control. Boy were we jazzed. I'd love to fly regularly with him but he lives about 40 miles SE from me. The field is another another 40 miles North from my house. So he spends 160 miles driving to go flying with me. We are looking to see if we can find a field a little more centrally located.

I'll take your advice and watch for the plane being pitch sensitive. I wonder how much of that is caused by the CG being set back for 3D flying?

John

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RE: Funtana 90 - 3/20/2005 6:12:27 PM

TManiaci

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