Thanks Kevin, actually I was giving consideration to Spring Air retracts.They are air up, spring down which offers a certain amount of security in the event of air failure. However, I personally favor the manuel retracts but never thought about it on a trike gear and I don't want to build this one tail dragger. I have no experience on electricts. Really my understanding of electricity is simular to my understanding of Greek. However, how much do they draw from a standard 7.2 v/110 amp nicad? Any chance of loosing radio power operating retracts? Just asking. Right now I am concerned about Spring Air. Ordered a set to replace Rhoms in my Chaos two weeks age and they haven't arrived yet. Surly the pony express can ford the Mississippi in two weeks. Any way thinks for input. Will advise of my decissions.

The Kraft retracts (and I think that there are modern equivalents) just use Servo motors inside (1 in each retract) so they draw similar power. They plug in just like a servo too (an amplifier about the size of a micro servo plugs into your retract channel and 3 wires from it pluig into the retracts. I have never had one hang up in all the years (too many!) that I have used them.

I hear good things about the Spring Airs. ONly thing is I constantly hear "I cant use retracts I fly off grass" which leaves me to believe that some retracts are not that strong. I have always flown off grass with the Krafts and never had any issues.

My Curare is coming along. I was delighted to find that the 6S 500 battery from my Trex 600 fits in just fine under the canopy. I just have to make the decision - to glass or to monokote. I am leaning towards the latter for weight - but still have a hankering after that gleaming epoxy finish! Silly really - once they are 5 feet away you cant tell!

I am quite tempted by the Atlas that DOn mentions - it would be an ideal home for one of my Webra 61 Rear exhaust motors. Cant have too many pattern planes!

I would like to enter a BPA contest - but to do so it either means an long trip (I live in Maryland) or tryng to get a group together and create an event up here. Anyone reading this interested?

Anyway ... let us know how your build goes!

I'm still waiting on Spring Airs for my Chaos. Had some old Rhoms but they leak and I have no idea how to repair so ordered two weeks ago new Spring Airs. Got an email they were retooling but would finally ship this week so should get installed and test the Utter Chaos. Where can I find about electric (Kraft) retracts. Sounds like I may consider them in the Curare instead of pneumatic. Really like mechanicals better, but not sure I want to go into the two servos deal. Still thinking about an engine for Curare. I have a 61 OS in another bird I'm not flying so make take it out for Curare. Save a couple hundred. Got to get another receiver. Have an extra 72 meg but probably go with 2.4 gig. Just a lot of stuff to buy for the Curare or take it out of other birds, which I don't like to do. May want to fly one of them and then go through to R&R. Give us pictures of how things are coming.

I have been flying two servo mechanicals (Hobbico's) off grass in my Curare for about 5 years now, other than a drop of oil on the pivots and sliding bits there has been no other issues. I use two 1/8" (3mm) nylon bolts on each leg, and never had a dingle to prove whether the bolts would actually break as intended... With modern batteries (1100mAh) there has never been any power/capacity issues either, even up to 10 flights per day. KISS works every time with retracts, just look at the thing every now and then and make sure the legs haven't bent and sticking in the wells and there really isn't much to go wrong with them.
Evan, WB #12.

I don't know about not flying off grass fields with retracts. I have three birds with retraccts, two mechanical and one with pneumatic Robarts. No problems but then again maybe our grass field is in pretty good condition. We have over 100 members in our club and several have retracts all on all sizes of birds with no problem. But then again maybe we keep the field in good condition by mowing weekly and occasionally, depending on rain, more often.

Kevin, where would I look for electric retracts? Can't google Kraft other then Phil who is now by by.

Yeah - everything Kraft is now bye-bye. I found mine by watching ebay etc. Although old they really work well and are great value when you can pick them up. All you have to do is change the Kraft plug for Futaba or JR. Years ago (late 70's) I flew pattern competitively (in England) and used the then state of the art Kraft Signature series radio (still have it - and still prefer its control sticks even to my 12X!!) - so I had some stuff left over from then (including the Curare I flew in the British Nationals!) - and some I got via ebay - brand new amazingly enough. If you are the patient type and can watch ebay (or other for sale lists like this site) - they are great retracts and SO easy to install.

I typed "electric retracts" into Google and found a couple of current vendors. You might want to check them out.

I'll post some photos of mine so you can see.

Kevin

I think the idea that retracts can’t be used on grass is a myth sort of like the myth about nose gears being difficult to use. Have no clue how this stuff gets started.

What, you mean people fly of stuff that ISN'T grass? What sort of stuff is it, and where do you get it from?
Evan, WB #12.

I am about ready to start building this Curare BUT, I can't read the plans to determine what additional wood and its size I will need. What do I do? I am measuring the triangle top and bottom side and then the thickness of the top and bottom fuse planks. Is that right and if not what is right. I can't find any numbers other then 25 X 18 triangler stock. It measures out on the plans 1/2 inch triangle but to lighten up I could use smaller say 3/8 in triangle. Same with the top planking measures 1/4 in. thick but how about 1/8 in. thick? This will be the first bird I have built from plans only and then not have them in English, which is the only language I understand.

You can measure the plan sizes in mm and convert to inch stock quite easily, it won't make any difference to the build. Use only the lightest stuff you can find for the fuselage, and it you decide to use thinner wood than specified, remember that you might not be able to achieve the same cross sectional shape, you might run out of wood to sand. There is a lot of wood in the Curare fuselage, and most of it ends up in the scrap bin.
Evan, WB #12.

Matadco,

I used 1 inch triangle for the top of the fuse and 3/8 triangle for the bottom. I used 1/2 inch for the top and 3/8 for the bottom. DO NOT go any smaller - or your fuse will look like a box instead of the beautiful rounded shape that you end up with after carving most of the above away! Also your ply fuselage members will be cut for this size of triangle and wont fit right if you skimp on the wood. Even with the size I used I was worried about shaving it too thin to achieve the nice rounded section needed.

Also... these things move pretty fast and are subject to quite a load as you do aerobatics - I dont think too light is the way to build. Also if you use soft balsa it really does not add much (or save much by skimping). I think you save more by careful use of epoxy (not too much) and using cyano when possible.

I ordered 2 sheets of 1/2 inch * 3, two of 3/8 * 3, 2 of 1/8 * 3, aileron stock, strip balsa for the trailing edges (remember I had foam wings), a couple of blocks (3 * 1 inches) for the nose etc., 2 sizes of dowel (for the wings and the removeable canpy, nose block etc. - [you may not want a removable nose block - but it is great for getting at an electric motor). I also ordered some 1/16 and 1/32 ply for re-inforcing the removable parts etc. , a little 1/8 ply for servo trays etc.and finally some hardwood "engine bearer" wood for mounting the retracts in the wings. That was about it I think. (I did not mention the wood for skinning my wings and tail as you dont have foam - but if it is not in your kit add that - I think 3/32 is normal for skinning built up wings and 1/16 over foam).

After that it was just hinges, servo extensions, the wire for the pull-pull ridder link, control surface horns, fiber glass for joining the wings and glassing the fuselage (have not decided about the wings yet - might use monokote).

Its hard to think of everything - and having just lost my local hobby store I am now reduced to ordering on line. I hope I am not violating any rules here by saying that I am delighted with the quality of both wood and service from Balsa USA.

Let us know how your build is progressing. I hope to post some photos of mine soon.

Thanks Kevin, you have been a world of help in this project. Trying to figure this out is considerable different then kit building. I have a short ruler with one side metric and the other side standard. The fuse top triangle stock calls for a 25 X 18 which according to this ruler is about 1" X 3/4". The bottom triangle is 10 X 10 which equals about a 3/8" X 3/8. I have also ordered another set of plans which I hope will be in English and std. measurements. I ran down some old articles and printed them off. The articles call for spoilers along with flaps and 3 servos in the wing, 1 for retracts, 1for alerons and one for the flaps. That would put 4 more in the fuse, one rudder, elevators one nose retract and engine. Is that what you have? The other side of the coin I could use pneumatic retracts but where do you put the tank and action valve? The Rhoms I had in the Chaos turned out to be ok. The problem was a line popped off at the wing cross over and the end went below the skin. I finally noted an open T but being forgetful, I exchanged it for a coupler and then one side main did not work but the air leak stopped. I finally reconnected all lines and everything works like it is suppose. I now have an extra set of new Spring Airs which I had intended to put in the Curare, but may change my mind and go with manuels and two retract servos. What do you think? About to decide to go with the OS power. That is what my hobby shop owner recommends who is ex competative pattern flyer and sponsored my two kids when they were competative pattern flyers but then again that is what he sells. I'm trying to get the list of woods together. Picked up a couple of pieces yesterday but will order the rest from Balsa USA. Porbably take a week to get here. Will keep you advised on progress. I thought I was a pretty good builder but this project is definately keeping me humble.

Since Servos are so cheap now (relatively!) I plan to put the aileron and flap servos in the wing in line with each control in the modern manner - so 4 (small, digital - Futaba 9650) servos in the wing - but not in the center as they did it in the 80's. I am going with the combined flap and spoiler arrangement like the earliest Curare - rather than the seperate flap and spoiler - really just to save effort and weight.

For the elevators I plan to do the same thing - putting a servo in each tailplane half (futaba 9650 again), mounted on plywood "covers" underneath each half. I use 2.4Ghz radio - so no worries about long servo leads.

So that leaves me with motor and rudder in the fuselage under the wing (remember I use electric retracts - just plugged in like servos). For the rudder I plan to use a "pull-pull" arrangement with fishing line. I am using a Futaba 9252 for that.

I think that there is plenty of room in the fus. in the space over the wing (or if , like me you mount the fuel tank there for balance you could put the tank up front where the fuel tank "should" be) for an air tank for pneumatics. The actuating valve could be mounted on the servo tray next to a retract servo (you would not need a particularly special servio just to actuate the valve). My other Curare (the one with the Webra 61 in it) has the tank mounted over the center of gravity (I used a Perry pump) so that the CG does not change as the tank empties. It works fine - but does consume space over the wing. Not such a problem with the new modern radio as it is much smaller.

I hear good things about OS engines I am sure that you will be happy with it - especially if you dont plan to use a tuned pipe al la SPA.

Kevin: Being unemployeed and unemployable I don't think I will go the digital servos route but rather stick to "el cheepos". However the idea of individual servos in the rear on elevators sounds like a plan. I to think moving the servos out in the wings for alerons is also a plan, which is what I do on all birds now. Fuel tank will be mounted according to planes, in the nose behind the firewall. I too am unsing a 2.4 gig and with that received takes up very little space and very little weight. So the small retract air tank can be mounted in fuse aft of wings.Using Spring Air with a small control valve and one air line would not take up the space the Robarts would. I also use a Hobbico mini servo to operate the control valve the same as I do on Rhoms in Chaos. It only requires a 1/4 travel and little resistance so the mimi servos are great space and weight savers. This leaves the battery pack forward of the wing saddle behind the tank which should off set the weight of the servos in the tail and keep balance. There is plenty of length in fuse but width is only about 2" , just wide enough for side by side cervos for rudder and engine over wings. This sounds like the plan but you know the best laid plans of mice and men are spoiled by things that might have been. I'll let you know. Again thinks for all your help.

Cheap curare canopy!
http://www.rcuniverse.com/forum/fb.asp?m=3445324

Kevin, just wondered if you ever received a canopy, which was the start of this thread. I finally got all stuff together for my Curare and have completed the horizonal fins and elevators. Got the wings framed up and now sheeting. Have only bottom side of one completed. Really havent started on fuse other then to glue the two piece sides together with reinforcement. Going with new OS 61 for power and new Futaba 7C 2.4 gig for guidance. Don missed #13 rib and took another week to receive it for completing framing up wings. I received my canopy, so now all needed is to get it finished. Have you completed yours and given it a fly?

Sorry to report no on both counts. I only have about 1 day total a week free to work on it - so progressis slow - but steady!

The canopy is nearing availability from the kind emails that I have received - so I have just left that part to complete later. I have completed the wings. I fitted flaps - so 4 servos. I used 2 futaba servos laying on their sides under a hatch cover so that only the arm pokes out and two Hitesc HS81's mounted in the same way for the flaps. Each cover being secured at the corners by a tiny sheet metal screw into hardwood blocks in the "hole" Looks nice and streamlined! I mounted the electric motor, but then spent some time wondering how I would eveer get it out if it failed. I ended up deciding to make the upper nose block removable - it will be help in place by screws. I also spent time wondering how to make the canopy removable (to change the battery) and ended up choosing a simple nylon screw mounted vertically in the fuse just behind the canopy with a plywood tounge that rotates when you turn the screw and locks into a slot in the canopy. I added some 1/32 ply to the canopy ends to beef them up a little.

Basically what is left is the canopy of course - and the upper nose block - which I cant really sand until I have the canopy attached to the frame, some internal work for a battery tray etc. then a big sanding job to get things really smooth before covering with Monokote. So far it is pretty light so I am happy with how it is turning out. I am spending far too much time assembling the pieces on my workshop floor and just sitting and admiring it!

Hey - by the way - when you do your fuse - fit all the parts (rudder sub-strake, fin and rudder etc.) before carving and sanding (dont ask me why I suggest this!!!!) There is a lot of carving and sanding - but I rather enjoy it! Even the wing fillets worked out great and I know a number of people have mentioned this can be a PITA! I did find that getting the nose area round quite hard.

This was the first time that I have built a model using cyano glue. It has pros and cons I think. It IS fast and that is great - but it is SO hard! becoming a real problem to sand soft balsa around. It sticks up and is hard to sand. I am having to use a little filler in those areas.

I'd love to hear more of your build experience - and i'd be happy to take some pix if you are interested in any part.

Kevin

Kevin, Spent the morning sheeting the bottom of other half of the wing. I don't know if I do the correctly but I glew the sheet with thin CA on all ribs, spars and LE & TE. I then have to cut out for aleron servos, which I have mounted on 1/16 ply hatches using 1/2" screws to afix to wing, then sand sheeting to match. I sheeted with 3/32 and then sand it down to about 1/16. I thin cut out for retracts. This all takes me about 3 hours plus per side. I have now epoxied the two half together before sheeting the top. The center ribs of each half are fully epoxied together under pressure. I am questing if I should also fiber glass tape the centers or if they will stay together without a strip of fiber glass. Opinions are welcomed. The plans call for 3/8 dihedral, which is almost straight. I ordered two other sets of plans which have all now arrived. They are in English but do not seem as complete as the origionals from Eureka which were in German. There really isn't a lot of explanation and only the three views, leaving much to imagination. Over the years I have built a lot of kits which have instruction booklets but this is my first build without instructions. As to covering I am giving consideration to fiberglass and paint. It will be heavier then monocoat so may depend on completed weight as to which finaish.

Would like to see pictures of yours and keep posting your progress

HI,

ABSOLUTELY glass the center of the wings. I use 3 oz cloth and epoxy resin.

The dihedral is three (3) inches under ONE tip - not 3/8 inch. I have seen a few Curares built without the dihedral and they dont fly well at all.

I'll take some pix this week.

have fun

Kevin

Ooops: Rechecked and it is 75mm instead of 7.5mm. 75mm is 3 inches where 7.5mm is 3/8. Looks like a cut and reglue. Just a senior moment. The little picture measured the 3/8" but read 75mm and then on my mm to inch ruler the note equaled the 3/8". I usually use 1/2 oz at about 6 inches width with epoxye then repeat at 5", 4" and 3 inches center strip. Little more time consuming but seems to give a smoother smooth finish.

It has now been a month since I started trying to complete this project. After the senior mistake on dihedral I cut the halves and reset the dihedral to the 75mm or 3 inch. I have now completed sheeting the top and am sandidng. I will be doing the center section fiberglassing later today then completely fiberglassing the entire wing.

Good to hear it is progressing. This week I finished the tailplane halves and mounted the retracts in the wing and the flap and aileron servos in their little cut outs covered with a ply/balsa sandwich hatch. It takes forever but looks very neat with just the control horn poking through.

Not too much left - join the wings, add the mounting dowel and bolts, finish the canopy (as and when I get one!), fit some ply for the battery holder and the receiver and rudder servo mount (above the wing) - and that will be about it apart from a marathon sanding effort.

It all takes forever and I really only have time for about 8 hours a week on it, but it is looking more like an airplane every day!

BTW: Did you glass the join of the tailplane halves?

Kevin

Kevin: haven't glassed the wing halves yet as I am still sanding. Filling the gaps between the wings with auto bondo then glass the center section. Should make a very strong joint. Spent all last week with contractors repairing the house from the February hail storm we had. Finally got most done except for some painting insurance company paid for and I will do to compensaste for the deductible for the rest of the damage. Actually, I am giving serious consideration to completeely glassing both wing and horizonal stab. I may even glass the fuse. Will wait until I get it done to make dicission. Keep us advised your progress.

Just a little up date on progress.  Got the wings joined and center glassed with 3 strips 1/4oz cloth starting at 6" wide, 4" wide and 2" winde.  Makes a good smoth  joint.  Got horizonal stabs together and center glassed with only one 1/4 oz. X 3" wide  cloth.  Got fuse together with engine installed along with retract servo, control and piping.  Mounting enginel up right rather then angle.  Just barly room enough for 61 OS to fit. Real tight but on center thrust line according to plans. Completing balsa block for nose is a pain and taking up lot of time fitting.  Still mounting elevators servos outside on each side of tail rather then using Y spred.  Rudder and nose steering arm installed to center servo.  Small air tank for spring air retracts mounted juist aft of wing hold downs.  I ordered all three copies of plans I could find.  The ones from Eureka that came with the kit are slightly smaller then the ones from MAN and the other.  Other plans in English and inches rather then German and meters but about 10% larger in measurements which make them rather useless.  Should have all completed in about a week and ready for painting.  Old time patern flyer in our club is going to help with epoxie painting.  His time goes back to 1960 Califirnia working with Phil Kraft and Dick Henson in pattern competing and designing models.</p>

Kevin, keep us posted on how you are progressing.</p>

</p>

Wow! You HAVE been busy!

My own progress has been somewhat slower - although I hope to take a couple of days off around the holiday and move forward.

I found that some things need to wait for each other. For example I wanted to get the maximum length possible for the undercarriage (to clear the bigger electric prop I will need to use - most likely a 13 by 8 or 13 * 10) So I had to mount the nose retract - adjust it to maximum length, mount the wing and adjust the main gear legs so that it sits level - and all this before I could cut out the holes in the wing for the wheels to retract into!!

Also I did not want to fit the tail until I had the wing dowel and rear mounts in place so that I could bolt on the wing and carefully align the tail.

I have also spent some time on air ducting to ensure that the motor and speed controller get air flowing over them. I also spent time hiding away the flap servos (I love the effect of coupled flaps on square turns etc. and they really do cut the landing speed in half) - I mounted them on their sides under hatches just like the ailerons - neat - but it all takes SO long!

Anyway - it is all coming together now, although the poor chap who I promised to buy a canopy from has been having issues with his mold - so I still dont have the top block and canopy in place on the fuselage - and I still have a happy day of finish sanding ahead of me - although you will have that fun too right? I have heard that the Klas Kote (maybe Class Cote) epoxies give an awesome shiny finish.

I have decided to use monokote to keep the weight down, although initial tests indicate that I can pull well over 1500 watts from my motor - which equates to more than 2 BHP - so it should not be lacking in power!

I am going to copy a finish design that I saw on line - I have uploaded a copy of it here - It was a wonderful piece of work that was documented on line - but sadly met an untimely end - but I love the design - tell me what you think!