Author Topic: Great Planes Extra 300s C/L ??? (Read 3004 times)

Bryan Higgins · « **on:** March 12, 2008, 05:54:44 PM »

Hello Modelers

I have new in the box a GP Extra 300s RC kit. After seeing a topic about kit bashing a Vector 40 to look
like a Extra 300 , It just crossed my mind why not change a real GP Extra 300s RC to a Control Line
Version.

I Know that the airfoil is not thick enough but what other problems would i run into ?

After seeing control line today and where i think it might be headed, It does not seem changing this
great model over to control line would be impossible. The fuselage shape could be a new turn in the
way control line models are headed and built. Certainly with todays new engine sizes and the new
C/L Saito four stroke models there should be enough power to help lift this type fuselage with a better
wing design.?

What do you think? Should i even attempt such a crazy idea? Bryan

Jim Oliver · « **Reply #1 on:** March 12, 2008, 06:08:09 PM »

I have a Goldberg Extra 300 RC kit I have been having the same thoughts about.

However, the kit wing is usless (too thin) and the fuse structure is too heavy for CLPA use. I have several kits of models designed especially for CLPA so I decided to sell the Extra and spend my time on something that I know will work.

My 2 pesos worth......

Cheers,
Jim

Leester · « **Reply #2 on:** March 12, 2008, 06:16:32 PM »

I'd say go for it, if it doesn't work well you'll have a nice model to look at.

.

Bottom line is it's your kit do what you want.

Wynn Robins · « **Reply #3 on:** March 12, 2008, 07:50:58 PM »

do it but make mods to the structure - the fuse will be WAY to heavy if you build it as is. - it would be very easy to chop an change the formers and supporting structures to make it lighter.

get a laser cut rib set form a good flying design of the same size, or a foam core -

change the numbers to suit a C/L model - again use a proven C/L model for the dimensions - the ratios on RC ships a quite different to what works for us

after all that - it should be real easy to get it sorted.....

Bryan Higgins · « **Reply #4 on:** March 13, 2008, 02:50:31 AM »

Thanks Wynn

I was thinking that it could work. Lighten the fuselage and build a proven wing design
for a 58" wingspan and about 4 pounds of total weight for the aircraft.

One things for sure it's different. And it would definitely turn heads at the field.

Thanks for the input , i may try it after my vector 40 build.

phil c · « **Reply #5 on:** March 13, 2008, 09:23:10 AM »

Bryan, what does the kit as it sits weigh? Do the numbers and see if you can come out with a reasonable weight and wing loading.
The original wing may be OK to use. I know Richard Oliver converted something similar with good success using the original wing. Great Planes seems to do a good job designing wings. If the original wing does turn out to be too thin you can substitute panels pretty easily.

If it is like most of the ARF's they used light plywood for most of the structure. The only good way to remove weight would be to cut the parts out of balsa ply and start over.

Bob Reeves · « **Reply #6 on:** March 13, 2008, 10:57:10 AM »

Quote from: Wynn Robins on March 12, 2008, 07:50:58 PM

do it but make mods to the structure - the fuse will be WAY to heavy if you build it as is. - it would be very easy to chop an change the formers and supporting structures to make it lighter.

get a laser cut rib set form a good flying design of the same size, or a foam core -

change the numbers to suit a C/L model - again use a proven C/L model for the dimensions - the ratios on RC ships a quite different to what works for us

after all that - it should be real easy to get it sorted.....

In the finishing stages of a SIG Somethin'Extra that I did exactly the above to... Never again.. Too much rework, might just as well build it from scratch or buy a good stunt kit and make the fuselage look like the Extra.

Bryan Higgins · « **Reply #7 on:** March 14, 2008, 10:38:27 AM »

Thanks Phil and Bob

I like SIG Somthin Extra's myself there a nice looking plane. So by the time you where finished
you could have built one from scratch or another C/L kit just as quickly.
I belive you, It would be easyer to just take a great C/L kit and change it a bit. And probably
much cheaper.
I will just shelve it for R/C use down the road. Right now im injoying Control line so much i
doubt i'll go back to flying remote control for a while. I really got tired of seeing ARF's in all my
RC magazines and at the store. So my Dad mentioned C/L which was somthing he taught me
long ago. And i really love building kit's. I should try building scratch, have'nt tryed it yet.

Thanks for the information. I appreciate it all. Bryan

Wynn Robins · « **Reply #8 on:** March 16, 2008, 04:09:07 PM »

send it to me - I will build it...

Rudy Taube · « **Reply #9 on:** March 17, 2008, 10:34:12 PM »

Hi Bryan,

I agree with those who said it may be more trouble than it is worth to make the conversion. Every time I look at one of my nice ARF RC scale planes I think of what it would take to make it fly CLPA, and each time the list is longer than I want to attempt!

With that said, I am working on using an RC Extra 300L FG cowl and building a CL fuselage around it. And use an RC canopy for it too. If you want to do the same, look at some of the electric Extras with around 40" WS and just order the canopy and cowl to use. This is what I did on my latest ECL project. Good Luck

Regards,

Bill Little · « **Reply #10 on:** March 18, 2008, 07:03:31 AM »

HI Brian,

As you have probably gathered, it isn't a question as to whether it is *doable*, it is. However, it WILL take some thought and work. Major consideration is which wing to use. There are plenty of wings that would fit the bill. I would say a wing like the Impact, Trivial Pursuit, or even Windy's 92 Cardinal. Those are pretty thick, proven, airfoils. I would use a pretty thick wing with adequate flaps to create the lift necessary for the weight of the plane. And I would power it with a pretty strong .60-.75 size engine!

I haven't seen the kit, but if the formers are lite ply like usual, than take a Dremel to everything you can! If you can get it around 70 oz., it should be great!

Bob Reeves · « **Reply #11 on:** March 19, 2008, 11:24:27 AM »

Stunt ship from hell..

catdaddy · « **Reply #12 on:** March 19, 2008, 03:18:36 PM »

Quote from: Bob Reeves on March 19, 2008, 11:24:27 AM

Stunt ship from hell..

Who's Nobler is that?

Bob Reeves · « **Reply #13 on:** March 19, 2008, 05:47:11 PM »

Bill Butterfields, I'm helping him make sure it gets together straight.

Mario Verol · « **Reply #14 on:** September 10, 2008, 11:46:07 AM »

Very nice topic! I have also in mind to bild a Piper J cub (RC) with almost 2 meter of wing. I beleave I will have no problem with the airfoil, couse the J3 is not disired as a stunt aircraft.
I think to use a third cable to the angine.
But, I have some works before to do it. Who know one day..

Bryan Higgins · « **Reply #15 on:** February 04, 2009, 06:15:28 PM »

Hello Mario
I belive someone in Model Aviation a few years back entered a Piper Cub in Control line Scale.
Can't remember his name offhand but the plane was real nice.

Building a J Cub in C/L would be really cool. Sounds interesting.

Glenn (Gravitywell) Reach · « **Reply #16 on:** February 04, 2009, 07:27:52 PM »

Two things:
1. If you are not interested in competeing at the CLPA level, build the ship, you will be pleasantly surprised. Just do as indicated and relieve it of as much weight as possible. Don't bother changing anything else and you will have a very fun, sport flying plane.
2. There was a young lady that campained a Sig Cub in control line stunt in the intermediate class, many years ago. I believe she took the event at the Nationals one year. So I believe again.....the plane is more than adequate for sport flying. Just build them and have fun....don't think too much. I know I don't and I have a lot of fun....I think!

john e. holliday · « **Reply #17 on:** February 05, 2009, 04:21:52 PM »

I remember the young lady that competed in scale with the SIG Piper Cub. I just can't remember her name. At one time it was her, a brother and dad that competed. Maybe Mike Gretz can come in on this as I think Hazel Sig helped the young lady out. I can't remember for sure but, I think she was on the scale team for the world champs once. The plane was never capable of doing stunts unless you call streamer/banner pick up a stunt. Where's Mike G. DOC Holliday

Bryan Higgins · « **Reply #18 on:** February 10, 2009, 07:42:55 AM »

Ah here it is.

Feb 2008 Model Aviation Scale pilots compete for FAI postions and big $$$

Richard Schnieder competed in F4b with his 56" Piper j-3 Cub C/L Model.
Powered by a Enya 46 Four-Stroke engine. He placed third for a spot on
the USA Team.....

FLOYD CARTER · « **Reply #19 on:** February 10, 2009, 11:01:10 AM »

You must be very careful when converting a R/C model to control line, especially one with a flat-bottom airfoil. R/C models typically set the wing at 2 or 3 deg. positive incidence. This must be taken out and set at 0- incidence.

My converted R/C model flew as C/L, but it immediately headed for the top of the circle, and would only fly level with almost full DOWN elevator!

Floyd in OR

Clint Ormosen · « **Reply #20 on:** February 10, 2009, 05:43:53 PM »

Quote from: john e. holliday on February 05, 2009, 04:21:52 PM

I remember the young lady that competed in scale with the SIG Piper Cub. I just can't remember her name. At one time it was her, a brother and dad that competed. Maybe Mike Gretz can come in on this as I think Hazel Sig helped the young lady out. I can't remember for sure but, I think she was on the scale team for the world champs once. The plane was never capable of doing stunts unless you call streamer/banner pick up a stunt. Where's Mike G. DOC Holliday

I remember that girl, but can't remember her name either. She used the Clipped Wing Cub from Sig. Even used the blue and white sunburst paint scheme.