I would love to use another Brillelli engine but it would probably be a G62 with EI if I go with the CMP Zero.

Hi Joe, Nice work on the retracts - I was wondering what foam glue are you using or is it just the expanding insulation type stuff. I like your idea of filling the retract mount cavities and wing tubes - makes a lot of sense about the additional strength gained.
Thanks
Butch

Butch, this is the stuff I use. once openned one of the parts cristalize in the bottle but i've found that stored upside down it stays liquid.


http://www2.towerhobbies.com/cgi-bin...&I=LXBH62&P=SM

Joe

Just out of curiousity, what is your opinion if you were still to have a mishap with the gear and/or gear mounts...how difficult is this stuff to remove if additional work in the area needed to be done? Being polyurethane, I'm thinking it might stick pretty damn well to balsa and ply. I might have to just play with some to check it out. Thanks for the link!

I usually buy ARF's for practice and fly-ins. that means I want to do the least to them to get them in the air. most come with some form of ply (usually Lt ply) for LG mounts. Marine ply is even a poor material here because a chain is only as strong as its weakest link, in the case of marine ply that is the glue between the ply layers. So on the typical ARF LG mounts I put a peace of .375x.375, or .25 x .5 maple under the ply. I want it to fit snugly between the ribs and use ample epoxy to hold it under where the retract mechanism ears will be. Left alone it wont take long for the movement in the ply to brake the ply bond. I mount the retract and get it all set up threading the sheet metal screws into the maple sandwiching the ply between the maple and retract mounting ears. The problem at this point is that the majority of stress still has to go through the ply which still gives the ply glue/lt ply as the weak point. To move the majority of the stress out of the ply I remove the retract mechanism and foam the entire area, so the foam is filling every nook and cranny in that wing bay. The next day when the foam is hardened up I cut out just what I need to fit the retract back in and a layer of fiberglass. Then I lay in 3ox of glass starting from the front LG mount, down the side of the foam, across the wing top sheeting, up the foam on the other side foam, and across the aft LG mount. Screw the LG back in and go fly. I’ve found this method to be as strong as if I did the install my self.

Joe

P.S. any Ideas for foam wings in my CMP fw190. I know what I would like to do but that would require a wing recover.

Joe - did you mount your retract air valve on the wing or did you just have it placed there for the pictures? I would like to eliminate as many of the air line quick disconnects as possible since I think they are the most problem prone for air leaks - I have the UP1 air valve and it would require 4 disconnects.
Butch

Butchn, I glued the valve and servo box on to the wing, and plan to put the reservoir in the fuse.. That leaves only one connection between the wing and fuse, the fill valve can be placed anywhere on the tank side of the valve. So if you want to put it in the wing put a tee in the supply line between the quick disconnect and the valve. If you want the fill valve in the fuse. Put a tee between the quick disconnect and the reservoir.

I had a plane I inherited that had four air lines between the fuse and wing. What a bear to assemble! I teed the two similar lines on each side of the quick disconnects to reduce from 4 to 2 and that helped a lot.

As for the UP# I have one for a set of spring airs not yet installed. They say it will give me a ability to slow down the gear on the way up. For everything else I use wheel collars over the line just after it comes off the barb on the cylinder (that allows me to adjust the rate at the field with the wing on). If a leak develops there I cut that ½ in.. peace off push the wheel collar on to the tubing and the tubing back on the barb again without removing the wing at the field.

Joe

I have the UP#5 on a set of Spring Airs and it works great - allows setting both up and down speed.

What style of Spring Airs will work best on the CMP 50cc Zero ?

I used 403's because I had them and am using Robart #662 struts - they are 7/16" diameter. If I were buying a set I would go with Spring Air 700's they are bored for 7/16" struts I believe. The 403's are larger than needed and require the use of the 1/2" adapter that comes with the Robart's. OOPS - I didn't see you were referring to the 50 size - then I would go with the 100 series retracts and struts that adapt to 5/32 or 3/16" wire gear - you can get the 100's in either size.

FYI - Tried the foam stuff from Tower for strengthening the retract area... me thinks that using a polyurethane glue like gorilla, or ultimate might be a better way to go. It won't give you as much foam per unit of mixture but I think it is stronger overall. I have not really done any shear test, but when using the dremel to shape the stuff it just feels like the glue (I used gorilla) was harder. Next time I will need to allow more room for the foam and fiberglass - things got kinda tight on my first shot at this but I think it is a great idea! Retracts mounts are now very solid and strong!

Butchn, remember the foams job is to give shape to the structural members. keep the LG rail in the same relationship to the D-section. and to give the fiberglass shape. if the foam breaks free of the stress bearing members they will begin to move in relationship to each other causing foam dust which I've gotten real good at finding. once found I Ca all jionts to close up any cracks in the epoxy in the joints. dig out all the foam I can reach and re refoam. as you no dought have found one needs to gain experience with this stuff. I tell everyone make two hole one to pour in ans one for pressure relief.

I've fit the G-62 engine to the box provided with the kit with blind nuts, then glassed it. pic's to follow.

Joe

Joe ,when will you have pics of the G62 mounted?

I’ve been concentrating my time on a P-51D with a os 1.2 4c. I had to put bearings in it then it would run for 4 minutes and quit. I tried everything I could think of and finally gave up and put it out of the way for the summer when I thought of a bad glow plug. Turns out the plug needed 1.25 turns to tighten it back up. I finally got a good flight on it Sunday. Hopefully tomorrow there will be someone at the field so I can test fly it to verify all the trim is correct then I will mark the trims and install a spectrum DX7 which I want to ring out real well this summer.

Next I have a IMP Macchi ready for maiden. Again hopefully tomorrow. With all the problems this summer I’m due for some luck. But this is the second plane out of the 120 models I’ve built that I’m not sure will fly so I plan to hope it. If at that moment it leaves the ground I’m able to keep the wings level we’ll climb out if not I’ll cut the engine and take what I get.

Then its back to the zero!

I’ve been thinking about cutting the cowl, it is pretty thin and I have to cut allot of it away and I’m worried about the cowl curling.

Dick, if your still tuned in I will have to cut it all the way to the back, do you think it will curl? Would a couple of layers of 2oz glass be a good idea?

Joe

Hi Guys,
Just finishing up CMP ZERO, moved all servos from rear to over wing area. Put rudder and tail wheel on pull-pull and each elevator on separate servo. Used a set of H-9 retracts from Giant P-47 with a sleeve over struts and 3/16 wire down the middle for extra strength. ( Total cost with servos $200.00 ) Took out the standard rails and made new ones out of maple and used Gorrilla glue as recommended. Have a US-41 for power. It looks like all up weight is 17lbs. with no additional weight necessary in nose. I hope power is enough. Engine swings a 18-10 prop at 6800 RPM. Didn't use the box up front, made some stand offs. Made wing a one piece, I don't mind transporting and like the extra strength. I should be done in about 2 weeks, any additional help would be appreciated. Really like the finish on this bird. They should fire the guy that wrote the manual.
many thanks,
Geo.

Geo sounds like a great build , how about posting some pics

Geo what size of Zero 80" 50cc?

Hi Geo

I just received my Zero yesterday (see http://www.wegier.ch/Modellbau/Baube...9/Default.aspx, unfortunately only in German). As I also plan to place the servos for the rudder and the elevator in the fuselage close to the wing I wanted to ask you if you could post some pictures of your linkage (especially from the elevator)?

Best wishes,

Richie

Hi again guys,
My ZERO is the 42-50CC size. I used the US-41 because I didn't want to buy another engine. I have four of these engines and one is in a bipe that weighs 22 lbs. and flies it satisfactory. I am hoping for scale speeds not a hot rod. Sorry at this time I can't post pictures. I don't have the savvy. I used the ply board in the fuse and just doubled where the servo screws are put in. The rudder servo is in the center with a giant double arm that has the rudder on the outside and the tail wheel on the inside. I crossed both wires coming from the tail. The cut outs for the evevator rods are on the bottom of the fuse and can't be seen. The rudder wires come in the same spot as on the original hook up. The two elevator servos are mounted on the outside of the fuse board nest to the fiberglass with the long arms facing to center. I used carbon fiber rods with 4-40 ends and is seems to be OK. I mounted the engine servo (mini) on the firewall. Hope this helps a little bit.
Geo.

Hi guys,

Just got my new RC Report today and Pettit has a article on this big bird. Good reading.

Geo.

Hi Geo.

I had a choice between a magnum 41(us-41 before tower took them over) and g-62 and I'm going with the g-62.

Joe

Paladin,I bought the Zero airframe from Dick after his review. I then bought G-62. I've never had gas or plane this big before so I'll be watching your build. Any details and pics greatly appreciated. Biggest problem is landing gear bent duing review flights. Dick gave me 1/4 inch wire for new ones. Also considering "inexpensive" retracts. One post says H9 P47 ones work.How much mods for this??? THANKS,Ressie

Ressie, Mine has been on hold for most of the summer, but I look forward to getting back to it. Anyway about retracts the install in the wing looks good and the mounting rails are close to maple stregth although the adheisive used is very brittle. I realy can not speak to what set works best as mine were CJ that I modified to fit. I would calll Spring-Air ten robart and see if they have a dropin set but that is some serious $$$.

Bending 1/4 cold rolled is a real treat.

Joe

Yep,trying to bend 1/4 inch stuff was when retracts started lokking real good With all this good flying weather mines probably on hold untill winter too.THANKS,Ressie

Ressie.
You can use a torch heat it up to orange then bend it then let the bend cool, brush the scale off it. heat it back up till it turns blue, then put it in a waiting oven turned up to as high as it can go and preheated to that. then turn to oven off and let it cool in there to room temp.

lots of work this way also

Joe