I have printed out the Curare plan and was going to start build it. However looking at the construction it seem very heavy, so there is in my opinion at the moment room for lightening. This doesn't bother me as I am making it more as a sport plane. I just enjoy building more than flying. However looking at previous posts I see these things can get up to 100mph+, so am I better to stick to the plan or can I use things like 1/8 balsa for the side rather 1/4 etc, and using balsa sheeting for the top deck rather than sanding a large block of balsa to the required shape.

I'm interested to hear what other builders have done and their opinions?

If you use 4-6 lbs or even 6-8 lbs 1/4" sides it should be fine. If one looks closely, the cross section of the model isn't really square but the sides are subtlely shaped to curve inward top and bottom to meet the curve of the top and botttom blocks, IIRC. This removes a lot of material.

Blocks as well. It might take a whole lot of time to acquire the lightest stock, but that's part of the fun of building a nice acro ship. When I shape blocks I tack glue them to the structure, finish shape them and then remove them from their position and hollow them out with a Moto-Tool so that I can see light through them. Never much more than 1/16th to 1/8th inch is left.

If you have the ability to form the top and bottom blocks from sheet, that'll be great. Whatever construction technique one chooses, the weight of the selected stock dictates the weight of the model. Every sheet of 1/16th, every block or scrap gussett should be cut from the lightest stock you can find. I wouldn't use anything but 4-6 lbs or 6-8 lbs density wood for your model. Built as per the plan, and with a lightweight finish, it should be a nice weight and fly well.

Chris...

Hi.

Are You building from Model Airplane News (MAN) published Curare plan, MK Curare plan or...?
I have built one from MAN plan and I have a MK Curare 60 kit and plan. If I compare the two plansI think a MAN plan built Curare maybe could be built slightly lighter. It is for sure some extra strength in the construction so here and there I'm sure You can make it lighter. But basic construction is probably wise to follow. These planes really was ballistic things that was fast as lightning with a good .60 - .61 2-stroke with pipe. Select balsa wisely (light, medium, hard) and you can save some weight at least. The Curare I had back in 1970th was rather light,it was covered with Skyloft (available anymore?), clear doped and finally painted with 2 component polyuretanbased paint. Curare was the best plane I used back then. I have a short kit of Curare,based on MAN plan [Edit - MKplan], from Eureka Aircraft now that I will start buildning, over 30 years since last time I built a Curare. http://www.eurekaaircraft.com/plan_kits/curare.htm

/Bo

Its the MK plan.

Bo,

Don's kit from Eureka is based on the MK plan not the MAN plan. Mitch is building one on another active thread at the moment. I think the model could be built to 2 lbs less if going electric. I wouldn't remove too much material on a 100 mph plane with a vibrating piped two stroke.

David.

I have built several of the pattern planes out of this era and have built them all in the manner you spoke of. I used contest grade balsa 1/8 inch sides. I created a full lenth, full profile fuse sides and rounded the top and bottom with 3/4inch tri stk. at the top and 1/2 inch tri stk at the bottom. You do lose the slight rounding of the middle of the sides, but is not noticable. I covered the wings with 1/32 balsa and the finish plane weighed in at a few grams under 6.5 pounds. I flew it with a .61 2stroke. The plane has over three hundred flights on it and it has not fallen apart yet. The thought was in those days that the plane would just disintegrate with such high speeds. That just is not true in this case. Understanding that the original was flown at 8.5 to 9 pounds with all the equipment he carried, the 6.5 plane is amazing to fly. Smooth and fast. My thought, lighten the load and have a ball flying it, besides it is a whole lot easier to build

dlq

David,

You are right, I just mixed the plans - I have the Eureka kit and both MAN and MK plan laying in same pile with wing+ stab+wood for Eureka Curare short kit. I was just to lazy to go to there and check what plan it was that belonged to the short kit. I have edited my previous post.
Thanks for the correction.

/Bo

Which of the good modern two strokes would suit this plane. I was thinking of a 0.S. 61fz with pipe?

The classic choice would be a Webra Speed. Hanno style.

I think that using 1/32" sheeting on cores is a great way to save weight. Fuse sides can also be thinned out. The rest of the concept is easier to follow in order to provide the required shape to the fuse.

In fact, I think I'll switch to 1/32" balsa sheeting on my next 60 size core.

David.

Been flying my all wood RCM&E plan Curare for a few years now, HP.61 Gold Cup with muffler, mech retracts (2 servos) and flaps. 6.75lb all up with standard wood sizes. It isn't the design, but the wood you pick and how much sanding you do that matters.
Evan, WB #12.