Flyboy Dave

My Feedback: (21)

....Hi rickpaw, welcome to R/C Universe.

I have a 60 size Cermark F-20....I would recomend air retracts. The mechanicals
are a constant battle.

Flyboy Dave.

rickpaw

Thanks Flyboy Dave,
I have both air and mechanical retracts, and I agree that mechanicals are a pain. Will Robart 510 fit the Juno F-20? I have a AK SU-27 as well, and I'm debating which one should I build first this winter.

toro_0397

hi i am new with speed planes, and i want a phoenix or a juno(dc) f 20. i dont care to build the juno kit, what i really care is whichone is a faster plane using an o.s 55 ax and juno f20 with installide retracts. about what speed can both models reach.

thanks

toro_0397

hi i am new with speed planes, and i want a phoenix or a juno(dc) f 20. i dont care to build the juno kit, what i really care is whichone is a faster plane using an o.s 55 ax and juno f20 with installide retracts. about what speed can both models reach.

thanks

vicman

My Feedback: (10)

How much diffrence are you looking for? There won't be much.
The Juno will be a much better plane over the long haul but may be a little heavier depending on how you build it.

Flyboy Dave

My Feedback: (21)

Like Vic says....there isn't much difference between all 4 or 5 of the 40 size F-20's.
If you are building one from a kit, you should minimize the size of the air intakes
on the sides of the fuse, and use retracts for all out speed.

The real key to the speed of the plane is the engine and prop. I use skinny wheels
instead of retracts, and the plane is plenty fast....in fact, too fast....because it has
flutter issues. The planes were design to go 100 mph top speed. Once you get above
110-115 problems arise. []

FBD.

toro_0397

do you think that the juno would be a better plane? what do you recomend to avoid flutter? and what kind of servos shuold i use?

thanks

bob27s

My Feedback: (19)

The Juno F-20 is a great kit, and results in a VERY good flying airplane....

Flutter is not prevented by the servos. Too many folks look for servos that can survive flutter. Best to address the source of flutter.

Seal the control surfaces gaps. That is the best way to prevent flutter. And be sure your torque rod linkages are properly installed.

Either aircraft does not need anything special servo wise. Anything you would trust in any decent aircraft is good. The F-20 I had a few years back had basic JR 517 ball bearing sport servos in it. Any decent BB modern BB sport servo would be good.

Although from a weight/size standpoint, you may want to consider some mid-size digital servos. Save an ounce or three in weight, and easier to fit into the plane.

As for engine choice..... the OS55AX will be ok. Keep in mind, the engine prefers lower rpm, but it can do ok for itself in a speed application. With either the stock muffler or at tuned muffler such as the Jett-Stream, select a prop that allows the engine to turn between 14,500 and 15,500 rpm peak rpm. With the stock muffler, a 9x8, 9x9 or 10x6, 10x7. With the tuned muffler, 10x7, 10x8, maybe the 9x9.

vicman

My Feedback: (10)

I have read other places here in RCU that several PHX models have suffered from poor hardware. (especially control horns) If you don't mind building get the Juno, they look great when done and will allow retacts, something the other .40 size F-20s don't. FBD's is a .60 size.
Bob said it right about flutter. I have never had a problem with flutter on any of mine. Usually it's poor piloting skills

toro_0397

thanks for all the help.
the only concern i have is that i have only built two kits, both of them profile 3d's, is the juno difficult to build what tips can you give me?

thanks

bob27s

My Feedback: (19)

It is a fairly straight-forward kit.

Just spend a night or two looking over the plans and reading the instructions before building. You can usually identify a few things you will want to plan-ahead for.

toro_0397

do you think that a 61 can be fitted on the f 20

burgh_guy61

My Feedback: (11)

Here is a pic of the nose of my DC (Juno) F-20. There is not a whole lot of nose room. This is a OS 46sf ABC in mine just to give you an idea of space. By the way, it has no retracts and has been on the radar gun at 105 straight and level.

vicman

My Feedback: (10)

Nice install.

My Kangke was radar'd at 106-110 consistantly over 8 or 9 passes. I have a stock clapped out .46 FX, no fancy pipe like yours

burgh_guy61

My Feedback: (11)

Laughing at the fancy pipe, actually that is one of the Tower cheapie pipes for a 46. I have yet to really lean on that 46 so far as it is still new with only about a gallon thru it and didnt try a 9x8 yet either, but never the less no complaints....except i didnt build it with retracts.

toro_0397

what spinner is that, it fit perfectly the plane. is the one of dc.
did the towers muffler show a notisable difference in comparisson to stock muffler.

burgh_guy61

My Feedback: (11)

The spinner is from Juno (dot) com. It is a 2 1/4" jet style that like you said looks and fits the kit perfect. As for the Tower muffler it did add a few rpm..about 600, but looks better than a stock muffler too

vicman

My Feedback: (10)

That pipe looks like a pspec copy.

BG61, I was just up in your hood last week. I had to go to Chesswick for a meeting.

airbusmech

My Feedback: (1)

NEED HELP!!

I just finished my Juno rc F20. Trying to get the radio,battery and switch in. What size of battery is everyone using and where did you mount your switch? I am using mechanical retracts.Pics would be great!

Thanks in advance!

pritz

hi Airbusmech I am also finishing an F-20-mine is a Cermark.Both GARY ARTHUR and I fly our F-20's at the BURLINGTON field. Come join us this Sping. What make of mech. retracts are you using?

airbusmech

My Feedback: (1)

I am using good old hobbico retracts! Can't wait to get this in the air! The spring invite sounds good!

burgh_guy61

My Feedback: (11)

From this pic you can see where I put the switch on my Juno F-20. It was one spot where I do not hold the plane. I honestly dont remember where the battery pack ended up to balance the plane. I will check over the weekend.

toro_0397

last night i ordered my f 20.
i am missing accesories, can someone tell me what accesories i need.
thanks
i hope i can build it!

airbusmech

My Feedback: (1)

Very nice thanks. Ya trying to figure out where to put the battery also.Did you run your anttena outside?

airbusmech

My Feedback: (1)

The instructions call for 5 3/4 from the leading edge..My f20 balances at around 4 1/2 with the spinner. Not many places to move the battery. Where did everyones end up?