karolh

That's a very nice looking model squadron you have there. Thanks for sharing.

Mark 5

Thank you for the compliment Karol, I just need some time to fly them.

Gryphus31

Hello world!

Just to keep this wonderful topic alive. Let me present you my CG extra still under construction. I had to stop all hobbies for 7 years due to my job but now I'm starting again. And daaamn... Feels like real construction is dead man what happened in the last few years?

Anyways, to the matter at hand. I tried to stick as much as I could to the original. All I did was reinforce the firewall and the head of the frame. I used the two servos system for the wings. The pull pull frame for the rudder. And I am putting a DLE 30 on it with a canister. I plan on changing the landing gear to a carbon or aluminum one though. As it is the plane weight 3,4kg engine included (sorry I'm from Europe, that would be... Around 7,5lb or something?).

Any advice or comment is of course welcome.

I'll try to upload some pics by the end of the weekend.

Cheers!

Waco

My Feedback: (265)

I think the DLE 20 would be better engine for it, the DLE 30 would make too heavy to fly good and really put a lot of stress on the air-frame, remember this is a 68 in. wing.

Mark 5

I agree with Waco, the DLE 30 will be too much weight and flight performance will suffer. I have a DLE 20ra in mine at 11lbs and I think it is a great combo. Remember, more is not always better.

Gray Beard

My Feedback: (-1)

It was designed for a .60 two stroke glow engine. Back in the day that quickly changed to bigger engines, mine has the YS 1.20 four stroke, that is 20cc. When the Zinoah 20cc came out it was tried but then the DLE came along and it's about a perfect match. Go back on the thread and ask Karol from Jamaica about it. The 30 is just added weight and over kill.
it was also designed for the standard 48 in Oz servos, they work fine but today's digital servos are better but dont waste your money on the high power servos. It's an IMAC design and is crap as a 3D plane. It is however the best Extra of any size I have flown.

OldScaleGuy

My Feedback: (2)

Welcome back to the best hobby there is. ARF's have pretty much taken over but there are still a few builders out there, i am glad to hear you are one of them. Enjoy your CG Extra, i flew mine a few days ago and still love it. Right now it is hanging up in a building at our local county fair. Hopefully a few will see it and enjoy it.

Gryphus31

Wow! Nice to see that this thread is still so much alive!
Thanks everyone for your comments!
To be honest I am now inclined to think that the Dle 30 was indeed a bit overkill. Unfortunately I bought it on the indications of my local supplier... Well.. What's done is done right? Furthermore I plan on putting a smoking system on it later on. Perhaps the extra weight will then justify the extra power.
Also I do believe it will end up weighting almost 11lb, as there is still quite some work to do. Mainly adding the canopy, the entire landing gear, the two lipos, the fuel tank (I put a bigger one btw, 450cc no idea how much that is in Oz) and most of all all the oracover on the wings.

I really need to take those pictures!

Gryphus31

Aaaand there you go guys

https://image.noelshack.com/fichiers/2017/29/6/1500757732-img-20170707-223510.jpg

https://image.noelshack.com/fichiers/2017/29/6/1500757759-img-20170707-223527.jpg

https://image.noelshack.com/fichiers/2017/29/6/1500757773-img-20170707-223458.jpg

Gray Beard

My Feedback: (-1)

If you read the thread you will see some of the average finished weights, you will be about average for weight.
Beware of recommendationsome from people that sell or supply items.chances at this point in time very few salesmen know anything about kit built planes but will sell you items they stock.
Example, a friend bought an ARF the same size as the CG extra but the manufacture called it a 120 size. It was a much lighter plane too. They were also a DLE AND HiTech dealer. They sold him on the DLE then tried to sell him 7 servos at almost 200.00 dollars a piece. For a light weight 60 size plane.
That company is no longer in operation.
Buyer Beware!
you said you beefed up the plane, hope you used some 1/8 aircraft ply for the fuse doubler, the weak spot I'd the fuse right in front of the wings LE.

Gryphus31

Indeed I have to agree with you. My saler also tried to sell me heavy duty servos which I refused in order to use standard metal bearings servos around 20 euros each. Problem was... I know my turf around servos. But gas engines are completely new to me. 10 years ago when I last build a kit (a cap 232 of around 1.5m wingspan BTW) gas engine where so uncommon I only dealt with nitro.

Guess I was a bit dumb on this call. I do hope it will fly as good as with a Dle 20. Even if, well... I paid a little too much and I'll have to do some modification to the frame to take on the vibrations and torque.

Gray Beard

My Feedback: (-1)

Nope, you weren't dumb at all, just didn't read all two hundred and fifty thousand posts on this old thread.
Hobby shops today tend to hire off the street, I learned that one day while trying to buy a Tower adjustable motor mount from Hobby Town in Los Vegas! Long Story!
Gas is so much easier then glow to operate. Way Better! Way Cheaper! Once you learn what your doing gas is idiot Proof!
if I was just starting out in the hobby all I would use is gas and/or electric! In my case I'm completely electric ignorant!

karolh

You are going to be pleasantly surprised with the excellent flying habits of your CG Extra. As most everyone has already suggested the DLE 30 is going to be too strong and maybe to heavy an engine for this rather light aifframe. Any of the current 20 cc gas engines will be an ideal power partner for your model while fitting a CF or alum. landing gear is an excellent idea and if installed with a slight forward rake will help lots in avoiding nose overs during takeoff runs especially if flown from a grass strip. I am aware that this thread is a very long one but it is certainly worth reading as it is filled with very good tips on making an already well designed model even better.

Gryphus31

Indeed. This thread is a wealth of information about this plane. Unfortunately I just discovered it yesterday. And I bought my engine 4 months ago already, when I came back to construction.
Gray Beard, you were talking about reinforcing the front of the airframe. Could you be more specific?
What I already did is put triangular balsa rods on all joints, as well as add an extra layer of wood to the firewall. I also covered the whole firewall and surrounding areas with epoxy.
What are your extra suggestions?

smkrcflyer

Will a DLE20 side exhaust fit in the cowl without sticking out the side or is the RA needed to keep the cowl intact? Anyone have pictures of the DLE20 on the plane?

karolh

The DLE 20 and stock muffler will fit inside the Extra's cowl without anything sticking out.

karolh

I feel so strongly that a 30cc engine will be the demise of this particular model one way or the other that although you have already purchased a DLE 30 it might be a good idea to keep it for another model or sell it and purchase a 20cc engine for the Extra.
The area for strengthing that my friend Gray Beard was referring to is the sides of the fuse directly in front of the landing gear area. The cutouts in the fuse doubler for this area if still in hand should be glued in or a new additional doubler made for this area of the fuse to forward to the bulkhead for the fuel tank compartment.

Cyberwolf

My Feedback: (4)

I have had the pleasure of owning and flying the goldberg extra, all i can say is its a fantanstic aircraft if built correctly.
But i have to agree with the others the DLE30 is just to much engine for that airframe.
The 20 is a much better match, power and weight wise.
like has already been said glue the knock outs in place that run from the gear to the firewall,and i even made a doubler for mine that glued into the inside then added the tri stock.
I think i used 1/16 or 3/32 aircraft ply for the doublers, to help keep the weight down.
Smart move replaceing the stock gear thats a must, the wire is not any good.
I like many others are useing a 120 YS SC 4 stroke.
needless to say it makes more than enough power to fly the plane.
Good luck with your build ill be watching for updates as you continue making progress.

Gryphus31

Hello everyone !

As promised, I quick update on the beast :
DSC6148Copie - HostingPics.net - Hébergement d'images gratuit

DSC6149Copie - HostingPics.net - Hébergement d'images gratuit

Just recieved my canister and the 19x8 prop.

I'll keep you posted

Gray Beard

My Feedback: (-1)

the weak spot on this plane is the fuse just in front of the wings leading edge. They used very thin ply for the doubler. The design was fine when used with a nice .60 or .90 glow engine but if you notice, most people started using the heavy 1.20 four strokes or the 20cc gas engines. The downward force of landings can snap the nose right off at this point. That's the voice of experience talking. Of course mine is very old and I'm sure there was some oil soaking into the Wood? Just look at it and give it some thought. After building a number of this kit I simply started cutting new doublers from 1/8 aircraft ply. Just an easy fix.

Gryphus31

Thanks for the tip.

Indeed I've been reading this info here and there. And I got it covered. As you can see I am leaving the front uncovered for now because I plan on doubling it with some hard wood. Two full panels of around 2mm thick (that would be... Around 0,5 inch I guess).
​​​​​Though I'm not yet sure about this thickness. Is it enough strong? Or too heavy? What's your opinion on this?

Gray Beard

My Feedback: (-1)

Made me Think! In the early 60s the US was teaching the metric system in school thinking we should go along with the rest of the world, I loved It! The adult population couldn't shift over so it's not used much, a little but not much. Ok, 3mm is about 1/8, I think.Our wood is milled to ASE, not sure how it's done in the rest of the World? You want to come close to doubling the thickness of the stock doublers is all. Our ply also has several different grades. What we call aircraft is a top grade with 5 or 6 layers. Someone else can tell you what type of wood is used, I can't remember. We also have light ply, three layers of softer wood. Use the really good ply, Aircraft!
Karol once sent me a conversion chart, it's in my saved files, well worth Downloading! It converts almost everything.
it's in my old lap top though, it completely crashed.

rmoss94

My Feedback: (3)

To convert millimeters to the decimal equivalent just multiply it by .03937 or divide it by 25.4.

OldScaleGuy

My Feedback: (2)

Just ran across this if anyone is looking for a kit.
https://www.rcgroups.com/forums/show...berg-Extra-300

karolh

Hey Gryphus31, what's the latest on your build. Is the Extra finished or maidened ? How about another update