n00bs Gonna Build a Carden

[gareth.ky]

Now that the fuse sides are on I'm looking at the small space there is to get to the forward wing anti rotation pin. I have big hands, its gonna be annoying to get them down in there. Any tips for what hardware to use or how to set this up?

[gareth.ky]

Humpty BUMP, see above. I always seem to update this threat a 1am when no one is looking.

[mark786]

Gareth,
I usually leave the bolt in the hole during transport so I only have to slip a allen driver in thought the hole. This may be one of those items that you retain in memory for your next Carden build. I have a lot of those things to remember for my next one.
If you had cut your lightning holes different it would have been easier. However if I remember correctly, the stock plywood side only has a large enough hole for the driver.
Attach is a picture of Walt's lightning hole on a 40%. Lots of room.
Mark

[gareth.ky]

There might be enough room in my lighting holes, I'll have to check tonight.

I went by Ace hardware and had a long look around. They had some plastic caps for socket head cap screws so you don't need tools to screw them in:



They didn't have the size I would need so I did some digging. Seems that they are made by Shear-Loc. The site has the Knurled style knobs in M4 Metric and #8. The knobs are not very big, only 1.3cm (1/2"). Good news is these could easily be retrofit onto a lot of peoples airplanes.

[gareth.ky]

I was hoping that I would get the incidences set on the wings but I'm not quite there yet. The wings and stabs should be set this week. I'll hold off on the pics till the incidences are done. I see a lot of questions on how best to do it in other build threads. The Carden directions are pretty terse and don't really tell you everything you need to know. My method is mostly taken from the Carden directions + bits I picked up from Walt and others. Its pretty straight forward and easy to do.

List 'o stuff I 'discovered' this weekend:

• Don't let the razor plane hit the sheeting.
• Hobbylite filler works great. (ask me how I know)
• The best tool for spreading Hobbylite is your finger.
• It's best to mix it up before you use it and maybe add a little water.
• The Master Airscrew razorplane works better than the Dremel plane (IMHO). Its cheaper too.
• Stick construction always takes longer than you think it will.
• The ghetto Boxfan+AC filter is the bomb. Get one.
• In fact, get anyhting that makes sanding easier, faster or safer.
• A propane heater is a much better investment than a Kerosene heater.
• Mr. Heater here can raise the temp in my uninsulated 2 car garage by 20 degrees, on low, in an hour.
• Burning propane creates water vapor which makes poly glue react faster. (Can you tell I like the propane heater?)
• My Jerk Chicken is way hotter than your "Japalenyos" or whatever it is.

Questions:

• How should I shape the leading edge of the wings, how blunt or pointy should it be?
• Is there anything I can do to toughen up the balsa on the LE & TE?

[dmichael]

Hey Gareth- looks good. I wanted to mention that, unless I'm wrong, Dennis designed the gear mounts to work without blind nuts so that, if the gear were to come under unusual stress, the threads would strip out of the hardwood and not pull the bottom of the plane out.

I have no blind nuts in mine with many flights and no problems.

Dave

[gareth.ky]

Thanks dmichael

The instructions do indeed tell you to drill and tap the hard wood and not use blind nuts. I didn't think I was going to find a metric tap and I had the blind nuts on hand and the Dremel was close by so...

The manual says "Tap for 8-32 x 1 1/2" Socket Head Cap Screws. Nuts are not required.". I read that to mean not necessary but it wouldn't hurt either. I figured with the tight clearance it was just easier not to bother with nuts.

The manual in general is very prescriptive. It tells you what to do, not how to do it or why your doing it. This is sort of a low point of the kit for a new builder. You don't get all the how and why parts until after the build is done. I hope that this thread is adding some of the how and why for newbies.

Next time I'll try it Dennis's way. Ace has metric taps that I could have used. All the motor parts are metric and I want to just take one set of tools to the field.

Stop by any time, feedback and advice is always welcome!

[gareth.ky]

Here are some pics of the fuse sticks going in.

I also finished up setting the wing incidences and installing the mounts. The pics and writeup are on my blog. Its just too late to try and convert it to FG code tonight.

[buttface]

Have a beer bro...

[gareth.ky]

Here is the Gieco Caveman style How-To on setting wing incidences. This is step #22 in the Carden manual for the 35% 260. This step gets about 1/4 of a page. Its not complicated or hard but it is something you have to plan out.

I'm going to assume that were starting with the wing tube socket installed (step #21) and the wings are done with the leading and trailing edge stock installed and sanded to shape.

First we are going to do all of the drilling that we can on a drill press. Drill 4 of the square mount pads and all 4 of the rectangular mounting brackets dead center with a hole sized to the diameter of the bolt your going to use. Carden suggests using 8-32, I'm using 4mm. With the remaining 4 square pads drill a hole for the blind nut, again dead center.


On two of those pads add an additional hole clear of the blind nut. This is the setup pin hole. The setup pin will keep the wings level when the anti-rotation bolts are removed. This is handy while you look around for your socket driver at the field. Its just an affordance for setup & tear-down and not a load bearing part.


Next find the root cap stock with the pre-drilled socket tube holes in it. Mark the center line of the plank and then transfer the locations of the mounting pads to the center line. Use one of the pads and a square to mark the locations of the pads. Cut these out inside the lines. Sand until the pads are a snug fit.


Install the blind nuts in the wing pads. Place the pads into the root cap holes you just cut. The setup pin hole should be pointing towards the tail. Tack glue the pads with some CA. I just did the 4 corners. I'm using polyurethane glue to install the root cap so it will make a good bond later on. Cut the root cap stock in half to make two root caps.


For each wing we need to glue in the wing root cap. To do you have to cut away some of the foam so that the pads are recessed into the wing root. To do this I just fit the root cap over the socket tube and lined it up with the center of the airfoil using the center line I drew earlier. Once its aligned I press the pads into the foam so it leaves a mark. Using a Dremel router I cut a deep pocket behind the blind nut so that no glue could enter the back of the nut. Then I set the router to cut the depth of recess needed for the pad and cut out the shape of the square mount pads. Test fit again and it should be good to go. Sand down the tube socket so that its flush with the root cap or even slightly inset.


Now to get a good fit between the wing root and the fuse sides. I think I saw this on FG somewhere else and it didn't look like it could hurt. Flip the fuse on its side, put the wing tube through the fuse and mount one of the wings on top. I use polyurethane glue to attach the root cap. Make sure to get adequate glue around the ply mounting pads. Glue is going to come through the seams where the mounting pads are so put some parchment paper between the fuse and the wing to keep it from sticking. The glue takes 2 hours to set up so this step takes a while. You may want to label the wings left & right at this time because its hard to tell which is which after the root cap is on.


Resist the urge to trim the root caps, all that extra material is going to come in handy. So now its time to set the incidences. Use a good digital level and an incidence tool. Make sure your table is flat and level and clean. Mount both wings on the fuse with the fuse flat on the table and upside down. Make sure that you got the right wing on the right side of the aircraft and that its underside is facing up. Use the incidence tool to find 0.0 incidence. Use a block of scrap balsa and some push pins to secure the wing in this position. Make sure at least one of the pins goes through the 3/8 square stock in the fuse sides. The soft balsa on the fuse sides is too flimsy to hold the wing and keep it from slipping. Take you hands off everything and verify the level still reads 0. Set both wings this way. The blocks will allow you to move the wing and find 0 incidence again consistently.


Now we have to find the locations of those blind nuts so we can bore a hole in the fuse side to match up with it. I have seen various methods suggested using tape or sharpened screws. This way is easier and, IMHO, more accurate. Use a pin to probe for the hole from inside the fuse. Don't worry, the pin cant go through the ply block in the wing root so it can't make big holes in the exterior of the fuse sides. Just the tip goes through the balsa, not the whole thing. The holes on the inside get covered up later. Once you strike pay dirt poke more holes all around to find the extent of the blind nut hole. This will help you see the center when you pull the wings off.


Pull the wings off and you should see spots on the fuse sides peppered with holes. Open up the center of each area with a pin or small drill bit. Make a sand paper drill from 220 grit paper and drill the holes but twirling it. Open up the hole until its the size of the perforated area. Slide the wings back on and check that all the blind nuts are accessible. You should also make holes for the setup pins at this time.


Now we glue the 4 remaining mounting pads to the inside of the fuse. The is the *critical* step. Once they are glued in the incidence of the wing is set and you cant change it. I do one wing at a time so I can have the incidence meter to make sure the wing is at 0. Use 30 minute epoxy, not poly glue, for this step. The poly glue could expand and seize the bolt. Put the epoxy on the back of the pads and screw them in place. Do not tighten the bolts down, just snug them. Check once again that the wing reads 0, it might shift when the bolts go in but I didn't have this problem. Then just walk away. Wait till the epoxy has cured before moving anything.


Now its time to mount the setup pin. Make the pin about 3 inches long and use poly glue to install it in the wing. You only need it to stick out about 3/8". If you leave it a little bit longer you can sand it down so its flush with the mount pad inside the fuse when the wing is installed. You may want to harden up the balsa around the setup pin opening with some thin CA. You'll have to drill a hole in the mounting pad in the fuse side to match up with the pin. I strongly suggest doing this on a drill press. I tried it with a hand drill but the wood tends to 'climb' up the drill and mess things up. The drill press took more time but the result was much cleaner.


Last step, add the balsa spacer and the retention bands. This is pretty easy, just glue the parts in place. You'll probably have to sand and shape the two forward bands to fit. Again I used 30 min epoxy so it didn't get into the bolts.

This is the after shot, both wings still read 0.0 degrees. There is no slop or wobble at all. The bolts fit but are very snug and its a bit of a challenge to get them engaged properly. I'm going to put a few flight on the airplane and see if things sort of shake/wear into position. I don't want to mess up a good thing with sand paper just yet.

[The Dirt Doctor]

	Quote: Originally Posted by gareth.ky
	Here is the Gieco Caveman style How-To on setting wing incidences. This is step #22 in the Carden manual for the 35% 260. This step gets about 1/4 of a page. Its not complicated or hard but it is something you have to plan out. I'm going to assume that were starting with the wing tube socket installed (step #21) and the wings are done with the leading and trailing edge stock installed and sanded to shape. First we are going to do all of the drilling that we can on a drill press. Drill 4 of the square mount pads and all 4 of the rectangular mounting brackets dead center with a hole sized to the diameter of the bolt your going to use. Carden suggests using 8-32, I'm using 4mm. With the remaining 4 square pads drill a hole for the blind nut, again dead center. On two of those pads add an additional hole clear of the blind nut. This is the setup pin hole. The setup pin will keep the wings level when the anti-rotation bolts are removed. This is handy while you look around for your socket driver at the field. Its just an affordance for setup & tear-down and not a load bearing part. Next find the root cap stock with the pre-drilled socket tube holes in it. Mark the center line of the plank and then transfer the locations of the mounting pads to the center line. Use one of the pads and a square to mark the locations of the pads. Cut these out inside the lines. Sand until the pads are a snug fit. Install the blind nuts in the wing pads. Place the pads into the root cap holes you just cut. The setup pin hole should be pointing towards the tail. Tack glue the pads with some CA. I just did the 4 corners. I'm using polyurethane glue to install the root cap so it will make a good bond later on. Cut the root cap stock in half to make two root caps. For each wing we need to glue in the wing root cap. To do you have to cut away some of the foam so that the pads are recessed into the wing root. To do this I just fit the root cap over the socket tube and lined it up with the center of the airfoil using the center line I drew earlier. Once its aligned I press the pads into the foam so it leaves a mark. Using a Dremel router I cut a deep pocket behind the blind nut so that no glue could enter the back of the nut. Then I set the router to cut the depth of recess needed for the pad and cut out the shape of the square mount pads. Test fit again and it should be good to go. Sand down the tube socket so that its flush with the root cap or even slightly inset. Now to get a good fit between the wing root and the fuse sides. I think I saw this on FG somewhere else and it didn't look like it could hurt. Flip the fuse on its side, put the wing tube through the fuse and mount one of the wings on top. I use polyurethane glue to attach the root cap. Make sure to get adequate glue around the ply mounting pads. Glue is going to come through the seams where the mounting pads are so put some parchment paper between the fuse and the wing to keep it from sticking. The glue takes 2 hours to set up so this step takes a while. You may want to label the wings left & right at this time because its hard to tell which is which after the root cap is on. Resist the urge to trim the root caps, all that extra material is going to come in handy. So now its time to set the incidences. Use a good digital level and an incidence tool. Make sure your table is flat and level and clean. Mount both wings on the fuse with the fuse flat on the table and upside down. Make sure that you got the right wing on the right side of the aircraft and that its underside is facing up. Use the incidence tool to find 0.0 incidence. Use a block of scrap balsa and some push pins to secure the wing in this position. Make sure at least one of the pins goes through the 3/8 square stock in the fuse sides. The soft balsa on the fuse sides is too flimsy to hold the wing and keep it from slipping. Take you hands off everything and verify the level still reads 0. Set both wings this way. The blocks will allow you to move the wing and find 0 incidence again consistently. Now we have to find the locations of those blind nuts so we can bore a hole in the fuse side to match up with it. I have seen various methods suggested using tape or sharpened screws. This way is easier and, IMHO, more accurate. Use a pin to probe for the hole from inside the fuse. Don't worry, the pin cant go through the ply block in the wing root so it can't make big holes in the exterior of the fuse sides. Just the tip goes through the balsa, not the whole thing. The holes on the inside get covered up later. Once you strike pay dirt poke more holes all around to find the extent of the blind nut hole. This will help you see the center when you pull the wings off. Pull the wings off and you should see spots on the fuse sides peppered with holes. Open up the center of each area with a pin or small drill bit. Make a sand paper drill from 220 grit paper and drill the holes but twirling it. Open up the hole until its the size of the perforated area. Slide the wings back on and check that all the blind nuts are accessible. You should also make holes for the setup pins at this time. Now we glue the 4 remaining mounting pads to the inside of the fuse. The is the *critical* step. Once they are glued in the incidence of the wing is set and you cant change it. I do one wing at a time so I can have the incidence meter to make sure the wing is at 0. Use 30 minute epoxy, not poly glue, for this step. The poly glue could expand and seize the bolt. Put the epoxy on the back of the pads and screw them in place. Do not tighten the bolts down, just snug them. Check once again that the wing reads 0, it might shift when the bolts go in but I didn't have this problem. Then just walk away. Wait till the epoxy has cured before moving anything. Now its time to mount the setup pin. Make the pin about 3 inches long and use poly glue to install it in the wing. You only need it to stick out about 3/8". If you leave it a little bit longer you can sand it down so its flush with the mount pad inside the fuse when the wing is installed. You may want to harden up the balsa around the setup pin opening with some thin CA. You'll have to drill a hole in the mounting pad in the fuse side to match up with the pin. I strongly suggest doing this on a drill press. I tried it with a hand drill but the wood tends to 'climb' up the drill and mess things up. The drill press took more time but the result was much cleaner. Last step, add the balsa spacer and the retention bands. This is pretty easy, just glue the parts in place. You'll probably have to sand and shape the two forward bands to fit. Again I used 30 min epoxy so it didn't get into the bolts. This is the after shot, both wings still read 0.0 degrees. There is no slop or wobble at all. The bolts fit but are very snug and its a bit of a challenge to get them engaged properly. I'm going to put a few flight on the airplane and see if things sort of shake/wear into position. I don't want to mess up a good thing with sand paper just yet.

The hardest part of building a Carden kit is setting the wing and stab incidences. It took me more time to do these steps than any other step (and there were lots of steps)!! But, done correctly, the plane will fly great!

I saw on Carden's website that Mike McConnville's new large plane had to have tail weight added to it even though he used a DA 200. It was probably due to the fact that they used the new "weight saving" cut out motor box parts!

TDD (aka Bobby)

[gareth.ky]

Ye gods Dirt Doctor, this thread has a lot of pics and I don't think its helping to quote a post that long! Can you edit that out of there?

Really for me the sheeting has been the worst part. Specifically sanding the sheeting. Setting incidences is easier and a lot less boring.

I'm on to the stabs now. I had to do some work to get the tube to sit level and square. I did pretty much exactly what Walt shows in his build threads. The glue is setting up now.

I spent two days this weekend hanging out with friends at a wedding in Tulsa so not much got done.

[gareth.ky]

I haven't done much on this project over the last two weekends. One was spent at a wedding and the last was spent coding in C for a new project. Nuts to my distractibility!

I'm currently stuck on cutting out the root plates for the H-Stabs. I made a couple of templates but each one seems to not be quite right. I think I really need to make a photocopy of the plans so I can make the template on paper and then transfer it to the 1/8" aircraft ply.

Carden updated their site yet again with a link to some cool phenolic control horns. I was looking for a set of these and couldn't find any. I even want so far as to get carbide scroll saw blades to cut my own! I got a set of these though. I'm learning that they price may look steep but the time you save is worth every penny.

[why_fly_high]

Get back to work on this beast! The IMAC season is fast approaching! You don't need no stinking code for IMAC.

Dan

[gareth.ky]

I got the root plates for the elevators cut, drilled shaped and fitted. I had tried making them a few times before and its always came out like crap. This time I had a photocopy of the plans to work from and they came out OK. all the holes are in the right places. I'll glue them up tomorrow night.

The G10 control horns are here from Carden and they look great. My new White Rose tail wheel is here too and it looks super sweet.

The next big job is hinging all the surfaces. I'm going to try and knock that out this weekend. I'm scared to cut the rudder in particular. I'm not sure hot to mark it so it matches the plans. Any hints?