WacoNut

Hi Guys,
I started the build of my Jack Stafford Chipmunk. The first thing on the list is to sheet the foam cores. This is my 1st build with foam wings so it will be a learning experience. I am glueing the 1/16" balsa wing skins together with Elmer's wood glue. I have 1 wing skin glued and drying. I will attach the wing skins to the core with Gorilla Glue and sandwich them back in the foam husk and add weight and let then dry overnight.
Jack Stafford Kits are builders kits so Iam sure this thread will take a while to complete. If it looks and fly's anything like my JSM Aircoupe I will be very happy. I will be powering the plane with an OS .52 4-stroke and the finish will be Sig Koverall and paint. You cannot get a better covering job out of Iron on coverings IMHO.
I will start posting pics of the build as soon as I start sheeting the wing cores.
Anthony

WacoNut

Wing skins for the right wing panel are glued and sanded with 400 grit paper to a smooth finish. You have to be careful not to put any dips in the wing skins, you just want to make sure all the glue joints are smooth. I sprayed both skins with hairspray on the side that will glue to the cores to keep them from absorbing too much glue. The core has been lightly sanded with 600 grit paper to remove any melted foam and smooth out the surface to accept the skins, you have to be very careful not to change the shape of the core. I will now apply a very thin coat of Gorilla Glue with a 4" faom paint roller to the inside of the skins. Once this is done I will spray a fine mist of water on both sides of the core to help activate the gorilla glue then apply the skins to the core and return them to the shucks and add approx 150lbs of weight on top of the shucks to assure a good bond of the skins to the core. You need to assure that you have a sturdy flat surface for this to maintain a straight wing panel.
Pics to come!!
Anthony

WacoNut

I have skinned the right wing panel and returned it to the shucks to dry. This is my 1st attempt at skinning a foam wing, hope it works.
Anthony

ekir

My Feedback: (1)

Good luck Anthony. You know I will watching your building progress

Ed

WacoNut

Thanks Ed,
Send me some pics of your Aircoupe, I am insterested in seeing how it is looking.
Anthony

WacoNut

I let the wing panel sit in the shucks for 5 hours to let the glue set and I couldn't resist pulling it out to see what I had. The wing panel turned out great. The skin does not appear to have any air bubbles under it and is adhered good and solid to the core. The panel also came out perfectly straight. I do not see much advantage to a foam wing, I can build a built up wood wing in less time and get it just as straight. I guess I will have to wait and see how I like the final wing.
Anthony

All Day Dan

My Feedback: (5)

It looks like you did the top and bottom panels at the same time. The gorilla glue starts foaming in a few minutes. You had to work fast. Did you spead the glue on the sheet first and then use the roller or did you apply the glue to the roller first and then rolled it on to the sheet?

WacoNut

I put the glue down on the skin in a squiggly pattern then rolled it out. I put very little glue on the sheeting, you could hardly tell the glue was there. Once I had the glue rolled out on both skins I used a spray bottle to mist both sides of the core. I applied the skin to the bottom of the panel starting at the L/E then rolled to the T/E then flipped the panel over and did the same to the top skin. As soon as I had both skins on I moved it straight to the shucks and put the weight on top to hold everything tight until it dried.
Next is to add the balsa T/E and L/E and wing tip. I will add these to the panel tomorrow.
Anthony

All Day Dan

My Feedback: (5)

Thanks for the details. I used to use contact cement and then I switched to epoxies both with good results. I'll give the gorilla glue a try next time.

WacoNut

I just glued the L/E and T/E on with the gorilla glue. I got a little too much glue on the T/E and some foamed out. I hope that it isn't a big deal when it comes time to sand everything. I like the foam wing so far.
Anthony

WacoNut

I almost went too far,
The 2nd wing panel needs to be sheeted while the other panel is still in a state that it will fit into the shucks, both panels are cut from the same foam board and they both have to be in the shucks in order to stack weight on them for sheeting.
I have the 2nd panel sheeted and it is drying in the shucks. I will add the L/E and T/E pieces when I remove the panel from the shucks this evening. I will then carve the tip blocks close to shape then glue them to the panels before cutting the aileron's out. I am still undecided whether or not to cut out a slot and add the T/E reinforcement and the Aileron L/E before cutting the aileron's out or add them after. I do not have a hot wire foam cutter so cutting the slot out may be very tough to do and get it right. Does anyone have any opinions here??
Anthony

All Day Dan

My Feedback: (5)

You are always better off if each wing panel is cut from seperate pieces of foam. It makes the entire process much easier. The aileron hinge support should be imbedded in the foam prior to the sheeting being applied. A 1/4 inch sheet of balsa about two inches wide and a little longer than the aileron will do it. If it's too late for that use a dremel tool in their router support to remove the foam and sheeting. Their 1/2 inch drum sander adjusted to the correct depth works great for this but it does make a mess. Glue on the wing tip, except where the aileron is, and sand it to its final shape. Cut out the aileron after the wing tip is on. The portion of the wing tip that is removed is glued back into place. Remove enough of the aileron to have the sheeting cover the exposed foam and leave a 1/16 inch gap all around.

ELTIGRE

guess its too late but I have used double sided tape -availible from WING MFG for wing skins with terrific results. clean, quick AND light.

WacoNut

I removed the 2nd panel from the shucks and everything looks good. I am finished working on the Chipmunk for the day, the wife and I are going to spend the eveing in the Home Theatre watching movies. Tomorrow after work I will shape the tips and figure out exactly how I will handle the aileron's. Looking at the plans it looks like I will have to move the firewall back a little to accept the 52 4-stroke. I have a friend getting me a measurement since I do not have my engine yet.
Later!!
Anthony
ps. Thanks for the tips!!!

WacoNut

Back to work on the Chipmunk,
My boy came home from Iraq wed. on a 2 week leave. he is gone for the day partying with some of his friends. I have the house to myself so back to work on the Chipmunk. I have the leading and traileing edges drying on the 2nd wing panel and I am sanding the 1st wing panel. Since this will not be a scale bird I have decided to deviate from the plans and increase the aileron area by 50%. Per plans the aileron's are 1.5" from leading to trailing edge. I will build them 2.25", the overall length of the aileron's will remain stock.
I am going to increase the ammount of counter balance on the elevator's and rudder by 50% also. This should make this plane rock in the air.
After this building experience I will no longer shy away from a foam wing plane. I think I still prefer a built up wing but working with foam is not bad.
Later!
Anthony

WacoNut

Both wing panels now have the leading and trailing edges installed and sanded. I tranfered the shape of the end of the wing onto the tip blocks and cut ehm 1/8" oversized and glued them to the wings. I have one tip sanded dow to final shape. It turned out good. I will finish up the other wing tip then both panels will be redy to cut out the servo pockets, landing gear block pochets and aileron's.
Anthony

WacoNut

I have both aileron's cut out and the T/E filler pieces glued into both wings as well as the aileron leading edges.
I have one aileron and wing capped off and sanded to shape. The wing turned out very well. I will finish the other wing up this evening and start cutting out the servo pockets. I need to get the servo pockets cut out and the holes bored thru the wings for the aileron servo's before joining the wing halves and cutting the landing gear block which spans the wing center joint. Here are a couple pics of the wing panel with the aileron finished.
Anthony

WacoNut

Servo pockets are cut out, I put the wing panels back in the shucks(bottom half) and cut a 4 deg. angle on the root end on my table saw to set the proper dihedral for the wing. My butt was really puckering pushing the panels thru the table saw but it worked great. I have the wing panels joined and drying. I will take some pics later. I am going to work on shaping the tail surfaces before starting construction on the fuselage.
Later!!!
Anthony

WacoNut

The wing is now complete other than servo pocket covers,hingeing aileron's,glassing center joing and final sanding. I am very happy with how the wing came out especially considering this is my 1st foam wing. I used Gorilla Glue for the entire wing build and the stuff works great. The glue foamed up and filled all the little gaps around the landing gear block cutouts and made a very strong bond as well as the wing center joint. I will now set the wing off to the side and finish up the tail feathers and start construction of the fuselage.
I will have to move the firewall back 3/4" to mount the OS .52 4-stroke and maintain the stock cowling location, this shoud be a easy modification to the build. The remainder of the fuselage will be built per plans.
Here are a few pics of the finished wing, the wing is perfectly straight and very light and strong. Foam wing to have their advantages.
Anthony

WacoNut

I have set the wing off to the side and I have the tail feathers sanded to final shape. JSM designs are a stressed skin structure, the skin provides most of the strength of the airframe. The fuse is made up of 2 3/16" sides and 8 formers, the formers have the radius to give the fuselage it's shape. You must wet down the fuse sides to get them to conform to the formers. The #4 and $5 formers are located foreward and aft of the cockpit. The cockpit floor keeps the fuse square while you are bending the fuse sides into position.
I started out by marking all the former locations on the fuse sides and glueing the 3/16" stringer to the top of each side. I also added the fuse doubler at the wing saddle. I then glued former#4 and #5 into position then glued the cockpit floor into position. Once this is dry I can wet the outside of the fuse sides and shape them to the formers then pull the tail togther and glue it in position and add the rest of the formers. This type of construction is a little more time consuming but it gives you a very light and strong fuse that has a nice scale round shape.
Here are a few pics of what I have so far.
Anthony

WacoNut

I have all the fuse formers in place and the fuse top. The stab is epoxied into place, the fuse tail end builds around the stab. I had to cut a new larger firewall due to moving the firewall back 3/4" to accept the OS .52 The new firewall worked out good. The top of the fuse sides and the sides of the fuse top get sanded flush to the angles on the fuse formers then a 3/16" piece gets glued on the corner then that will get sanded to the round shape of the fuselage. I will leave off the bottom fuse sheeting until I have the control rods ran for the tail surfaces and throttle.
Here are a few pics of how the fuse looks now.
Anthony

WacoNut

have the top of the fuse sheeted and ready for sanding to shape(have I mentioned I hate sanding). The fuse is starting to take shape and I can tell already this is going to be a very sharp plane.
For those who may be interested I know JSM still has a couple of these kits on the shelf and that Steve from JSM is watching this thread. IF anyone is thinking about getting one of these kits you better speak up.
Once I get the fuse top sanded to shape(I hate sanding) I will epoxy the fin in place. I need to make a trip to the hobby shop sometime this week to pick up control rods, Robart hinge points and a tail wheel bearing assemble and some wire to bend a new tail wheel wire. The tail wheel hinge point is 1" behind the rudder hinge point requireing 2 control rods if built per the plans. I am modifying this by moveing the rudder hinge point back 1/2" and the tail wheel foreward 1/2" and hooking them up together. This will have minimal impact on the looks of the plane. I am increasing the rudder counter balance so I will maintain the same ammount of rudder surface. With this modification it will save some weight in the tail and easy of connection and maintenance.
Here are a few pics!!
Anthony

mmattockx

Steve, if you are out there, send me a PM.


Mark

WacoNut

I have the fuse top rough sanded to shape,
It is really starting to look like something, I can resist so I am going to trim the canopy to size and trim and assemble the cowling to see how it is going to look.
Anthony

Charlie P.

Treat yourself and get a little $6.50 razor plane. No dust, and it feels like you are making a guitar or cello as you peel off long, smoothe strips of balsa . . . till you hit the dried glue and then it's back to the 80 grit.